Mold Toxins like Ochratoxins Harm Humans and Mammals
James Schaller Appeals for Physicians to Read About Water Intrusion Illnesses
A "Best Doctor," "Peoples Choice Award MD," and "Top Doctor" according to physicians and patients, appeals for more mold and bacteria attention in sick patients working or living in sick buildings.
1. Chin J Physiol. 2010 Oct 31;53(5):310-7.
Antioxidant effects of melatonin and coenzyme Q10 on oxidative damage caused by single-dose ochratoxin A in rat kidney.
Yenilmez A, Isikli B, Aral E, Degirmenci I, Sutken E, Baycu C.
Department of Urology, Eskisehir Osmangazi University Medical Faculty, Eskisehir, Turkey. firstname.lastname@example.org
In the study, the effects of relatively high single-dose of Ochratoxin A (OTA) and the antioxidant effects of Melatonin (Mel) and Coenzyme Q10 (CoQ10) on OTA-induced oxidative damages in rats were investigated. A total of 28 male Sprague-Dawley rats were divided into four groups of 7 rats each: Control, OTA, Mel+OTA and CoQ10+OTA groups. Malondialdehyde (MDA) levels in the plasma and glutathione (GSH) levels in whole blood were measured; kidneys (for histological inspection and for apoptosis detection by TUNEL method) and bone marrow samples (for chromosome aberration and mitotic index) were taken. The rats in the OTA group showed limited degeneration of tubular cells. In some tubules karyomegaly, desquamated cells and vacuolization were observed by light microscopy. Mel and CoQ10 treatment significantly reduced the severity of the lesions. MDA levels of the OTA group were significantly higher than the control, OTA+Mel and OTA+CoQ10 groups, while GSH levels were significantly lower than the control, OTA+Mel and OTA+CoQ10 groups. Higher incidences of apoptotic bodies were observed in the kidneys of the OTA group although OTA administration did not significantly change the incidence of apoptotic bodies when compared to the control and antioxidant administrated groups. Although the percentage of the mitotic index was lowest in the OTA group, no statistical difference was found among the groups. Additionally, OTA had no numerical and structural significant effects on chromosomes. It was observed that single-dose OTA administration caused oxidative damages in rat kidney and Mel or CoQ10 treatment appeared to ameliorate the OTA-induced tissue injuries.
PMID: 21793342 [PubMed - indexed for MEDLINE]
2. Toxicol Sci. 2011 Aug;122(2):406-14. Epub 2011 May 27.
Site-specific in vivo mutagenicity in the kidney of gpt delta rats given a carcinogenic dose of ochratoxin A.
Hibi D, Suzuki Y, Ishii Y, Jin M, Watanabe M, Sugita-Konishi Y, Yanai T, Nohmi T, Nishikawa A, Umemura T.
Division of Pathology, National Institute of Health Sciences, Tokyo 158-8501, Japan.
Ochratoxin A (OTA) can induce renal tumors that originate from the S3 segment of the proximal tubules in rodents, but the results of conventional mutagenicity tests have caused controversy regarding the role of genotoxic mechanisms in the carcinogenesis. Human exposure to OTA from various foods is unavoidable. Therefore, an understanding of OTA-induced renal carcinogenesis is necessary for accurate estimates of the human risk hazard. In the present study, a 13-week exposure of gpt delta rats to OTA at a carcinogenic dose induced karyomegaly and apoptosis at the outer stripe of the outer medulla (OM) of the kidney but failed to affect the reporter gene mutations in DNA extracted from whole kidneys. This site specificity resulting from the kinetics of specific transporters might be responsible for the negative outcome of in vivo mutagenicity. The kidney was then macroscopically divided, based on anatomical characteristics, into the cortex, the OM, and the inner medulla, each of which was histopathologically confirmed. Spi⁻ mutant frequencies (MFs) but not gpt MFs in the OM after a 4-week exposure to OTA were significantly higher than in controls despite the absence of cortical changes. There were also no changes in 8-hydroxydeoxyguanosine levels in kidney DNA. These results strongly suggest the involvement of a genotoxic mechanism, with the exception of oxidative DNA damage in OTA-induced renal carcinogenesis. In addition, the reporter gene mutation assay using DNA from target sites could be a more powerful tool to investigate in vivo genotoxicities.
PMID: 21622941 [PubMed - indexed for MEDLINE]
3. Toxicol Lett. 2011 Jul 28;204(2-3):118-26. Epub 2011 Apr 29.
Aristolochic acid I and ochratoxin A differentially regulate VEGF expression in porcine kidney epithelial cells--the involvement of SP-1 and HIFs transcription factors.
Stachurska A, Kozakowska M, Jozkowicz A, Dulak J, Loboda A.
Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Aristolochic acid I (AAI) and ochratoxin A (OTA) cause chronic kidney diseases. Recently, the contribution of hypoxic injuries and angiogenic disturbances to nephropathies has been suggested, but underlying mechanisms have not been fully clarified yet. In porcine kidney epithelial cell line, LLC-PK1 cells, treatment with non-toxic doses of AAI increased whereas with OTA decreased production of vascular endothelial growth factor (VEGF), the angiogenic factor with well-defined functions in kidney. Moreover, the activity of transcription factors regulating VEGF expression was differentially affected by examined compounds. Activity of hypoxia inducible factors (HIFs) and SP-1 was increased by AAI but diminished by OTA. Interestingly, AP-1 activity was inhibited while NFκB was not influenced by both toxins. Mithramycin A, a SP-1 inhibitor, as well as chetomin, an inhibitor of HIFs, reversed AAI-induced up-regulation of VEGF synthesis, indicating the importance of SP-1 and HIFs in this effect. Additionally, adenoviral overexpression of HIF-2α but not HIF-1α prevented OTA-diminished VEGF production suggesting the protective effect of this isoform towards the consequences exerted by OTA. These observations provide new insight into complex impact of AAI and OTA on angiogenic gene regulation. Additionally, it adds to our understanding of hypoxia influence on nephropathies pathology.
Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
PMCID: PMC3154282 PMID: 21554934 [PubMed - indexed for MEDLINE]
4. Histol Histopathol. 2011 May;26(5):543-9.
Cytotoxic effect of ochratoxin A on the renal corpuscles of rat kidney: could ochratoxin A cause kidney failure?
Abdu S, Ali A, Ansari S.
Cell Biology and Histology, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia. email@example.com
To demonstrate that Ochratoxin A can cause kidney failure as the kidney is the primary target for OTA cytotoxicity. Ochratoxin A (OTA) is a mycotoxin found in our food. The cytotoxic effect of a low cumulative dose of OTA on the renal corpuscles of the kidney tissue has been investigated in this report. This study was based on two groups in which weaning albino rats were used: (1) control; (2) OTA-treated rats (289 µg/kg/day). After 28 days of treatment, a significant decrease in body weight, kidney weight and relative weight were detected in OTA treated rats. Serum creatinine and urea level were slightly elevated. These results revealed significant histological as well as ultrastructral lesions in the OTA treated group. The lesions included global congestion in the renal tissue and loss of demarcation between the cortex and medulla. The normal architecture of the renal corpuscles was destroyed and most of the corpuscles lost their ordinary look. The most apparent histopathological changes were urinary space disappearance and hypercellularity. In addition, congested, undifferentiated, atrophied, hypertrophied, fragmented, sclerotic, degenerated, and obliterated renal corpuscles were distinct. The ultrastructural lesions observed in the renal corpuscles in OTA on treated rats included; proliferation and swelling of the endothelial cells with occasional loss of fenestrae; narrowing of the capillary lumen; damaged podocytes with deteriorated secondary foot processes, hypertrophied and proliferated mesangial cells with expanded mesangial matrix. The endothelium was clearly defected and vacuolated, and lost its fenestrations in many glomerular capillaries. In addition, the glomerular basement membrane (GBM) became visibly thickened and tortuous. Necrotic glomerular cells were frequently observed. Pre-apoptotic cells were also seen. It was concluded that the exposure to relatively low OTA concentrations induced significant lesions to the renal corpuscles. Moreover, it activated oxidative damage and necrosis which can cause extensive damage to the kidney and ultimately kidney failure.
PMID: 21432769 [PubMed - indexed for MEDLINE]
5. Toxicology. 2010 Nov 9;277(1-3):49-58. Epub 2010 Sep 9.
Evaluation of a urinary kidney biomarker panel in rat models of acute and subchronic nephrotoxicity.
Hoffmann D, Fuchs TC, Henzler T, Matheis KA, Herget T, Dekant W, Hewitt P, Mally A.
Department of Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany.
Several novel urinary kidney biomarkers were recently approved by the US-FDA and EMA for improved detection of nephrotoxicity, but few data regarding their performance are publicly available so far. In this study, we investigated the potential of some of the newly accepted makers (Kim-1, β-2-microglobulin, cystatin C, clusterin) along with six additional urinary key proteins of kidney injury (GST-α, Timp-1, VEGF, calbindin, NGAL/lipocalin-2, osteopontin) to detect proximal tubule damage in the rat model studying either acute drug-induced kidney injury or subchronic nephrotoxicity. Candidate proteins were measured in urine samples obtained from rats treated with gentamicin (0, 60 and 120 mg/kg bw for 7 days), BI-3 [3-pyrrolidineacetic acid, 5-[[[4'-[imino[(methoxycarbonyl) amino]methyl] [1,1'-biphenyl]-4-yl]oxy]methyl]-2-oxo-, methyl ester,(3S-trans)] (0, 100, and 1000 mg/kg bw for up to 14 days) or with the mycotoxin ochratoxin A (OTA) (0, 21, 70 and 210 μg/kg bw for up to 90 days) using a Luminex(®) xMAP(®) platform. Cystatin C and NGAL appeared to be the most sensitive indicators of gentamicin nephrotoxicity, with significant changes occurring as early as day 1, and importantly before alterations in serum creatinine or blood urea nitrogen (BUN). Altered urinary excretion of KIM-1, clusterin, calbindin and Timp-1 accompanied by a rise in BUN was observed in rats with BI-3 at 1000 mg/kg bw for 14 days. In contrast, histopathological alterations induced by OTA, which preceded effects on traditional clinical parameters, were best reflected by changes in urinary Kim-1. Overall, our data confirm increased sensitivity of new markers as compared to traditional clinical chemistry parameters.
Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.
PMID: 20816719 [PubMed - indexed for MEDLINE]
6. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2010 Nov;27(11):1566-73.
Lifetime, low-dose ochratoxin A dietary study on renal carcinogenesis in male Fischer rats.
Mantle P, Kulinskaya E.
Centre for Environmental Policy, Imperial College London, London SW7 2AZ, UK. firstname.lastname@example.org
Carcinoma arising from male rat renal parenchyma is an aspect of the nephrotoxicity of ochratoxin A (OTA) and is a factor in considering application of animal data to human health risk assessment. We present experimental data to complement already published and to complete dose-response findings for dietary OTA. From 34 rats, only four unilateral renal carcinomas (12%) developed during a 2-year exposure to dietary OTA, contaminated to give the same weekly overall dosage as in the 50 µg kg(-1) gavage-dosing regimen of an NTP study (30%). Statistical analysis included adjustment for premature leukaemia deaths, resulting in the carcinoma incidence of 35% (10-81%), and showed no significant difference from NTP (incidence of 43% (23-49%)) due to the smaller number of animals. However, absence of microscopic neoplastic renal lesions in premature decedents argues for minimal effect of the 47% leukaemia on carcinoma expression in the present experiment. This would fit with previously published findings showing significantly less carcinoma expression from a regimen administering an OTA dose in feed than was achieved by a lower dose by gavage as in the NTP study. It is concluded that chronic gavage administration of OTA to male rats may optimise carcinoma incidence for toxicological purposes, but that the dietary mode gives data more applicable to assessing putative health risk for humans.
PMID: 20694869 [PubMed - indexed for MEDLINE]
7. Ann Pathol. 2010 Jun;30(3):240-2. Epub 2010 Apr 14.
[Karyomegalic interstitial nephritis: A new French case].
[Article in French]
Verine J, Reade R, Janin A, Droz D.
hôpital Saint-Louis, AP-HP, Paris, France. email@example.com
Karyomegalic interstitial nephritis (KIN) is a rare and slowly progressive chronic interstitial nephritis (CIN) (28 cases reported), described for the first time by Mihatsch et al. in 1979. Here, we report on a 50-year-old woman who presented with asymptomatic renal failure and mild proteinuria without hematuria. Renal biopsy showed large tubulo-interstitial fibrosis and massively enlarged tubular epithelial cell nuclei, without viral inclusion. KIN is a rare CIN defined by a karyomegaly of tubular epithelial cell nuclei. Its pathogenesis remains obscure. Nevertheless, an exogenous factor is suspected, ochratoxin A particularly. The familial clustering of patients and the frequency of HLA-A9 and HLA-B35 haplotypes suggest the presence of a possible genetic susceptibility to this disorder.
2010 Elsevier Masson SAS. All rights reserved.
PMID: 20621605 [PubMed - indexed for MEDLINE]
8. Hum Exp Toxicol. 2011 Feb;30(2):110-23. Epub 2010 Apr 22.
Protective effects of melatonin and Glycyrrhiza glabra extract on ochratoxin A--induced damages on testes in mature rats.
Malekinejad H, Mirzakhani N, Razi M, Cheraghi H, Alizadeh A, Dardmeh F.
Department of Pharmacology and Toxicology, Faculty of veterinary Medicine, Urmia University, Urmia, Iran. firstname.lastname@example.org
The effect of Glycyrrhiza glabra extract (GgE) as a natural antioxidant and melatonin (MEL) on ochratoxin A (OTA)-induced histopathological damages on the testes and oxidative stress was evaluated in male rats. The animals were assigned into four groups (n = 8) including control and test groups. The rats in control group received saline and the animals in the test groups received (200 µg/kg) of OTA, (15 mg/kg) of MEL + (200 µg/kg) OTA and (100 mg/kg) of GgE + (200 µg/kg) OTA, respectively, during 28 consecutive days. The serum total antioxidant power (TAOP) and total thiol molecules (TTM) production were assessed. Moreover, histopathological and histochemical studies were also performed. The results showed that the TAOP and TTM were decreased in OTA-exposed rats, while the animals that received MEL + OTA or GgE + OTA showed an enhancement in the serum TAOP and TTM levels. Histopathological analyses demonstrated that in OTA-exposed rats, the testicular degeneration, seminiferous tubule atrophy, dissociation of germinative epithelium, vasodilatation with vascular thrombosis, perivascular immune cell infiltration, hypertrophied leydic cells, giant cell formation, and negative tubular differentiation index (TDI) were observed. Surprisingly, both the biochemical and histopathological examinations showed that MEL and GgE, albeit with some differences, exerted a protective effect on OTA-induced damages. In conclusion, this data suggest that OTA contamination in animal feeds and human foods could cause reproductive abnormalities. Our data also indicate that OTA, at least partly by interfering in oxidative stress system, exerts its toxic effects on testes whereas MEL and GgE with antioxidant properties could fairly protect rats against OTA toxic effects.
PMID: 20413560 [PubMed - indexed for MEDLINE]
9. Toxicol Lett. 2010 Mar 15;193(2):152-8. Epub 2010 Jan 7.
Ochratoxin A induces G(2) phase arrest in human gastric epithelium GES-1 cells in vitro.
Cui J, Xing L, Li Z, Wu S, Wang J, Liu J, Wang J, Yan X, Zhang X.
Department of Pathology, The Second Hospital, Hebei Medical University, Shijiazhuang, China.
Ochratoxin A (OTA) is a mycotoxin commonly found in several food commodities worldwide. OTA exposure was involved in the nephrotoxicity, hepatotoxicity as well as immunotoxicity in experimental model. Our previous study showed that the high level of OTA contamination in wheat might be related to the high incidence of gastric carcinoma in rural area of China. However, there were no available data regarding the gastric toxicity of OTA up to now. In the present study, we explored the toxicity of OTA in human gastric epithelium immortalized cells (GES-1) by analyzing the regulation of the cell cycle, apoptosis and its molecular mechanism. We found that OTA could induce GES-1 cells arrested in G(2)/M phase. Among these cycle-arrested cells, the proportion of cells in M phase was down-regulated after OTA treatment by the mitotic index and the level of phospho-histone H3. Thus, it was clear that OTA exerted a major influence on G(2) phase arrest instead of M phase. We further detected the expression of the key factors which are critical to the G(2)/M phase transmission such as Cdc25C, Cdc2 and cyclinB1. The cyclinB1-Cdc2 complex was reduced and the expression of Cdc25C, Cdc2 and cyclinB1 were significantly decreased by OTA treatment both at protein and mRNA level, respectively. Considering that the cells may undergo apoptosis or death due to the cell cycle arrest, so we next detected the apoptosis of cells by OTA treatment. The results confirmed that OTA did induce apoptosis of GES-1 cells and activate the cleavage of capase-3. In conclusion, cell apoptosis and G(2) phase arrest mediated by Cdc25C, Cdc2 and cyclinB1 may be the initiating event in the gastric toxicity of OTA.
Copyright 2010 Elsevier Ireland Ltd. All rights reserved.
PMID: 20060447 [PubMed - indexed for MEDLINE]
10. Acta Pol Pharm. 2009 Nov-Dec;66(6):689-95.
Spermatotoxic effect of ochratoxin and its amelioration by Emblica officinalis aqueous extract.
Chakraborty D, Verma R.
Toxicology Division, Department of Zoology, University School of Sciences, Gujarat University, Ahmedabad 380 009, India. email@example.com
The present study was carried out to evaluate the spermatotoxic effect of ochratoxin and it's amelioration by Emblica officinalis aqueous extract. When male albino mice were treated with ochratoxin (50 and 100 microg/0.2 mL of olive oil/animal/day for 45 days, orally) alterations in various reproductive parameters were observed (sperm count, sperm motility, sperm viability and fertility rate), when further treated with the aqueous extract of Emblica officinalis (2 mg/animal/day for 45 days) amelioration was noted in ochratoxin-induced spermatotoxic effect. Oral administration of ochratoxin for 45 days caused, as compared to vehicle control (Group 2), dose-dependent significant (p < 0.05) reduction in cauda epididymal sperm count, sperm motility, sperm viability and fertility rate (Groups 4, 5). Oral administration of aqueous extract of Emblica officinalis alone did not cause any significant changes in above mentioned parameters (Group 3). However, Emblica officinalis aqueous extract along with ochratoxin treatment caused significant recovery in all the sperm parameters as well as in fertility rate (Groups 6, 7) in comparison with ochratoxin alone treated animals (Groups 4, 5). Amelioration was higher in high dose ochratoxin plus extract treated animals than that of respective low dose. When normal human sperm cell suspension was treated with ochratoxin (in vitro), various morphological alterations were observed. These were mitigated further, when treated with aqueous extract of Emblica officinalis.
PMID: 20050533 [PubMed - indexed for MEDLINE]
11. Front Biosci (Elite Ed). 2010 Jan 1;2:133-42.
Ochratoxin A induces craniofacial malformation in mice acting on Dlx5 gene expression.
Napoletano M, Pennino D, Izzo G, de Maria S, Ottaviano R, Ricciardi M, Mancini R, Schiattarella A, Farina E, Metafora S, Cartenì M, Ritieni A, Minucci S, Morelli F.
Institute of Genetics and Biophysics A Buzzati Traverso CNR, Naples, Italy.
Ochratoxin A (OTA) is a mycotoxin produced by fungal of Aspergillus species absorbed in human through contaminate food in gastrointestinal tract. OTA has been demonstrated to be teratogenic in a number of species including mice and potentially human. Mice exposed in uterus to OTA develop craniofacial abnormalities such as exencephaly, microencephaly, microphthalmia and facial clefts. An important role in differentiation of maxillofacial are exerted by the Hox related genes Dlx and Msx. In the present investigation we have confirmed that 2.75 mg/kg body weight OTA, given at gestational day 7.5, induces significant developmental craniofacial anomalies in mice and we have demonstrated the down expression of Dlx5, a member of Dlx gene family, that seems to be responsible of the observed deformities. These results support the hypothesis that Dlx5 is a target for ochratoxin and the inhibition of its function, directly or indirectly, could be at origin of the observed differentiation defects.
PMID: 20036863 [PubMed - indexed for MEDLINE]
12. Exp Toxicol Pathol. 2011 Jan;63(1-2):125-30. Epub 2009 Nov 22.
Liquorice plant extract reduces ochratoxin A-induced nephrotoxicity in rats.
Malekinejad H, Farshid AA, Mirzakhani N.
Division of Pharmacology and Toxicology, Department of Basic Sciences, Urmia University, PO Box 1177, Urmia, Iran. firstname.lastname@example.org
To evaluate the protective effect of liquorice plant extract (LPE) on ochratoxin A-induced nephrotoxicity, rats were exposed to ochratoxin A for 28 consecutive days. Biochemical analyses showed that ochratoxin A elevated the serum level of creatinine, blood urea nitrogen (BUN), alkaline phosphatase (ALP), alanine aminotransaminase (ALT), and malondialdehyde (MDA) while antioxidant power of the serum was diminished significantly (P<0.05). Histopathological examinations revealed degenerative symptoms in proximal tubules, congestions in renal tissue, and a remarkable infiltration of the inflammatory cells as signs of ochratoxin A nephrotoxicity. Moreover, total antioxidant power of the serum and MDA generation was increased. The test compounds melatonin (MLT) and LPE alleviated most of the biochemical alterations. The results of the histopathological investigations of the kidneys supported these findings confirming the protective effects of the test compounds albeit with some differences in antioxidant potency. Taken together, our data may suggest that LPE like MLT could alleviate an ochratoxin A-reduced antioxidant power of serum and lower the toxin-induced MDA generation. Hence LPE might be considered as a practically antioxidant compound that may be beneficial in the prevention and treatment of ochratoxicosis.
Copyright © 2009 Elsevier GmbH. All rights reserved.
PMID: 19932604 [PubMed - indexed for MEDLINE]
13. Chem Res Toxicol. 2010 Jan;23(1):89-98.
Structures of covalent adducts between DNA and ochratoxin a: a new factor in debate about genotoxicity and human risk assessment.
Mantle PG, Faucet-Marquis V, Manderville RA, Squillaci B, Pfohl-Leszkowicz A.
Centre for Environmental Policy, Imperial College London, London SW7 2AZ, U.K. email@example.com
The potent renal carcinogenicity of ochratoxin A (OTA) in rats, principally in the male, raises questions about mechanism. Chromatographic evidence of DNA adducts after (32)P-postlabeling analysis contrasts with experimental attempts to demonstrate the absence of OTA in such adducts. Proffered schemes for alternative epigenetic mechanisms in OTA carcinogenicity remain unsatisfying, while structural data substantiating DNA-OTA adducts has also been lacking. We report refined (32)P-postlabeling methodology revealing one principal adduct isolated in small amounts from the kidneys of all five Fischer and five Dark Agouti rats to which OTA had been given on four consecutive days. We also describe structural data for the principal adduct from OTA/DNA interaction in vitro and its subsequent preparative isolation by the postlabeling methodology (as C-C8 OTA 3'dGMP), essentially creating an ochratoxin B-guanine adduct. Reasoning for the unsuitability of experimental protocols in published evidence claiming nongenotoxicity of OTA is given. In vivo exposure of renal DNA to cycles of adduction with OTA, necessarily protracted for carcinogenesis to occur, can reasonably explain an occasional focal neoplasm from which metastasizing carcinoma could develop.
PMID: 19928877 [PubMed - indexed for MEDLINE]
14. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2010 Jan;27(1):72-88.
Mycotoxic nephropathy in Bulgarian pigs and chickens: complex aetiology and similarity to Balkan endemic nephropathy.
Stoev SD, Dutton MF, Njobeh PB, Mosonik JS, Steenkamp PA.
Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, Students Campus, 6000 Stara Zagora, Bulgaria. firstname.lastname@example.org
Spontaneous nephropathy in Bulgaria, which is observed frequently during meat inspection and which differs morphologically from the classical description of mycotoxic porcine/chicken nephropathy as made in Denmark, was found to have a multi-mycotoxic aetiology being mainly provoked by a combined effect of ochratoxin A, penicillic acid and fumonisin B1 in addition to a not-yet-known metabolite. Mean contamination levels of ochratoxin A were consecutively low (188.8 and 376.4 microg kg(-1)) in contrast to high contamination levels of fumonisin B1 (5564.1 and 3254.5 microg kg(-1)) and penicillic acid (838.6 and 904.9 microg kg(-1)) for 2006 and 2007, respectively. Some other mycotoxins with lower importance such as citrinin, penitrem A, etc., may also influence clinicopathological picture of this nephropathy. A heavy contamination with Gibberella fujikuroi var. moniliformis (Fusarium verticillioides) and Penicillium aurantiogriseum complex (mainly Penicillium polonicum) was observed in almost all examined feed samples coming from pig and chick farms with nephropathy problems from Bulgaria. In contrast, low contamination with Aspergillus ochraceus, Penicillium verrucosum and Penicillium citrinum was observed in the same feed samples and these species were isolated as very rare components of the mycobiota.
PMID: 19753495 [PubMed - indexed for MEDLINE]
15. Am J Pathol. 2009 Oct;175(4):1686-98. Epub 2009 Aug 28.
Molecular characterization of preneoplastic lesions provides insight on the development of renal tumors.
Stemmer K, Ellinger-Ziegelbauer H, Ahr HJ, Dietrich DR.
Department of Human and Environmental Toxicology, University of Konstanz, Konstanz 78457, Germany.
Kidneys are the second most frequent site for chemically induced cancers in rats. However, there is still limited information on direct effects of carcinogens on pathways involved in the development of kidney tumors. Since transformed tumor cells have different characteristics than their cell of origin, it was hypothesized that healthy tissue and progressing stages of preneoplastic lesions are differentially influenced by chemical carcinogens. To elucidate this question, TSC2(-/-) Eker rats were gavaged with genotoxic aristolochic acid or nongenotoxic ochratoxin A for 3 and 6 months, respectively. Histopathology and cell proliferation analysis demonstrated a compound- and sex-specific onset of preneoplastic lesions. In contrast, comparable gene expression profiles of laser-microdissected preneoplastic lesions from carcinogen-treated and control rats, including reduced expression of genes involved in carcinogen uptake and metabolism, point to a compound-independent lesion progression. Gene expression profiles and additional immunostaining suggested that clonal expansion of renal lesions appears primarily driven by disturbed mammalian target of rapamycin complex 1 and mammalian target of rapamycin complex 2 pathway regulation. Finally, prolonged carcinogen exposure resulted in only marginal gene expression changes in tubules with normal morphology, indicating that some tubules may have adapted to the treatment. Taken together, these findings indicate that the final outcome of in vivo carcinogenicity studies is primarily determined by time-restricted initial events, while lesion progression may be a compound-independent process, involving deregulated mTOR signaling in the Eker rat model.
PMCID: PMC2751564 PMID: 19717638 [PubMed - indexed for MEDLINE]
16. Chem Res Toxicol. 2009 Jul;22(7):1221-31.
Metabonomic study of ochratoxin a toxicity in rats after repeated administration: phenotypic anchoring enhances the ability for biomarker discovery.
Sieber M, Wagner S, Rached E, Amberg A, Mally A, Dekant W.
Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany.
For early detection of toxicity and improved mechanistic understanding, GC/MS-, 1H NMR-, and LC/MS-based metabonomics were applied to urine samples from a rodent toxicity study on the mycotoxin and renal carcinogen ochratoxin A (OTA). OTA was administered at doses of 0, 21, 70, and 210 microg/kg body wt for up to 90 days. Urine samples were collected at 24 h intervals 14, 28, and 90 days after the start of treatment and analyzed with GC/MS, 1H NMR, and LC/MS. Principal component analysis and orthogonal projection to latent structures discriminate analysis (OPLS-DA) based on GC/MS and 1H NMR data discriminated controls from animals dosed with 210 microg/kg body wt OTA as early as 14 days and animals dosed with 70 microg/kg body wt 28 days after the start of treatment, correlating with mild histopathological changes in the kidney. Integration of histopathology scores as discriminators in OPLS-DA models resulted in better multivariate model predictivity and facilitated marker identification. Decreased 2-oxoglutarate and citrate excretion and increased glucose, creatinine, pseudouridine, 5-oxoproline, and myo-inositol excretion were detected with GC/MS. Decreased 2-oxoglutarate and citrate excretion and increased amino acid excretion were found with 1H NMR. Increased urinary glucose is a well-established indicator of kidney damage, and altered excretion of TCA cycle intermediates (citrate and 2-oxoglutarate) is found as a general response to toxic insult in many metabonomics studies. Other markers are associated with cell proliferation (pseudouridine), changes in renal osmolyte handling (myo-inositol), and oxidative stress (5-oxoproline), established mechanisms of OTA toxicity. LC/MS was also able to discriminate controls and treated animals but contained more noise, and marker annotation was only speculative due to lack of reference databases. Use of multiple analytical platforms for metabonomics analysis may result in a more comprehensive metabolite coverage and may be applied to obtain mechanistic information from conventional rodent toxicity studies.
PMID: 19610676 [PubMed - indexed for MEDLINE]
17. Food Chem Toxicol. 2009 Oct;47(10):2419-24. Epub 2009 Jul 3.
Minimum tolerable exposure period and maximum threshold dietary intake of ochratoxin A for causing renal cancer in male Dark Agouti rats.
Centre for Environmental Policy, Imperial College London, South Kensington, London SW7 2AZ, UK. email@example.com
In rats fed dietary ochratoxin A (5 ppm for 3, 6 or 9 months) no renal tumours occurred throughout natural life of the group treated for 3 months, during which the ochratoxin dose was 3 times that in the high dose group of the NTP study. Bilateral renal carcinoma occurred in one rat in the 6 month group. Four rats treated for 9 months developed unilateral renal carcinoma. Overall latency between ceasing toxin exposure and discovering tumours was 35-97 weeks. Experimental verification of a 'no observable effect level' was made for feed containing 400 ppb, equivalent to approximately 7 microg ochratoxin A/day for Dark Agouti rats for up to 2 years, during which mean daily dose commenced at approximately 50 microg/kg, but later for adults was in the range 30-20 microg/kg. This data doubles the daily in vivo threshold dose from the NTP study ( approximately 15 microg/kg), and could influence human risk assessment. An at least 3 month threshold period for exposure to exceptionally high daily OTA intake (90 microg; 640-450 microg/kg) raises doubts over interpretation of experimental molecular data for OTA exposure at lower dose for up to 3 months in studies aimed at understanding carcinogenic mechanism.
PMID: 19577606 [PubMed - indexed for MEDLINE]
18. Toxicol Appl Pharmacol. 2009 Sep 15;239(3):284-96. Epub 2009 Jun 16.
Low doses of ochratoxin A upregulate the protein expression of organic anion transporters Oat1, Oat2, Oat3 and Oat5 in rat kidney cortex.
Zlender V, Breljak D, Ljubojević M, Flajs D, Balen D, Brzica H, Domijan AM, Peraica M, Fuchs R, Anzai N, Sabolić I.
Unit of Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia.
Mycotoxin ochratoxin A (OTA) is nephrotoxic in various animal species. In rodents, OTA intoxication impairs various proximal tubule (PT) functions, including secretion of p-aminohippurate (PAH), possibly via affecting the renal organic anion (OA) transporters (Oat). However, an effect of OTA on the activity/expression of specific Oats in the mammalian kidney has not been reported. In this work, male rats were gavaged various doses of OTA every 2nd day for 10 days, and in their kidneys we studied: tubule integrity by microscopy, abundance of basolateral (rOat1, rOat3) and brush-border (rOat2, rOat5) rOat proteins by immunochemical methods, and expression of rOats mRNA by RT-PCR. The OTA treatment caused: a) dose-dependent damage of the cells in S3 segments of medullary rays, b) dual effect upon rOats in PT: low doses (50-250 microg OTA/kg b.m.) upregulated the abundance of all rOats, while a high dose (500 microg OTA/kg b.m.) downregulated the abundance of rOat1, and c) unchanged mRNA expression for all rOats at low OTA doses, and its downregulation at high OTA dose. Changes in the expression of renal Oats were associated with enhanced OTA accumulation in tissue and excretion in urine, whereas the indicators of oxidative stress either remained unchanged (malondialdehyde, glutathione, 8-hydroxydeoxyguanosine) or became deranged (microtubules). While OTA accumulation and downregulation of rOats in the kidney are consistent with the previously reported impaired renal PAH secretion in rodents intoxicated with high OTA doses, the post-transcriptional upregulation of Oats at low OTA doses may contribute to OTA accumulation and development of nephrotoxicity.
PMID: 19538982 [PubMed - indexed for MEDLINE]
19. Pol J Vet Sci. 2009;12(1):89-95.
Influence of low doses of deoxynivalenol on histopathology of selected organs of pigs.
Zielonka Ł, Wiśniewska M, Gajecka M, Obremski K, Gajecki M.
Division of Veterinary Prevention and Feed Hygiene, Department of Veterinary Public Health Protection, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, 10-718 Olsztyn, Poland. firstname.lastname@example.org
Deoxynivalenol is one of mycotoxins that are most frequently determined in animal feed manufactured in Poland. The examination of histopathological lesions concomitant with deoxynivalenol intoxication is difficult because of the common, often synergistic, reaction of this mycotoxin with other toxins, such as zearalenone or ochratoxin A, which has a strong nephrotoxic activity. The possibility of estimating histopathological lesions in the course of intoxication with pure toxin at various doses is therefore of interest. Dosages used in this experiment relate to clinical cases observed in feeding the animals with whole ration feed obtained by processing feedingstuffs contaminated with Fusarium moulds. However, concerning the fact of one-shot administration of clinically pure toxin, the main question was if it was a sufficient dose to cause changes in the histopathological picture of gastrointestinal tract organs. The experiment was carried out on 12 nursery pigs of mixed breed (Polish White Large x Polish White Ear-pendent) with an average body weigh of 35 kg. The experimental nursery pigs were divided into 3 groups: group I (n=4)--control; group II (n=4)--DON administered at a dose of 0.2 mg/kg b.w.; group III (n=4)--DON administered at a dose of 0.4 mg/kg b.w. After slaughter of the animals, macroscopic examination was performed and segments of duodenum, jejunum, ileum, liver and mesenteric lymph nodes were sampled and assigned for histopathological examination. The results obtained equate to the clinically observed signs in swine production involving some nutrient metabolism disturbances in the gastrointestinal tract in the course of deoxynivalenol mycotoxicosis. Histopathological examination of segments of the duodenum, the jejunum, the ileum, the liver and the lymph nodes indicate that the regressive lesions are more expressed in the experimental group treated with the highest concentration of deoxynivalenol.
PMID: 19459445 [PubMed - indexed for MEDLINE]
20. J Biochem Mol Toxicol. 2009 Mar-Apr;23(2):87-96.
Toxicities induced in cultured human hepatocarcinoma cells exposed to ochratoxin A: oxidative stress and apoptosis status.
El Golli Bennour E, Rodriguez-Enfedaque A, Bouaziz C, Ladjimi M, Renaud F, Bacha H.
Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Rue Avicenne, Monastir, 5000, Tunisia.
Ochratoxin A (OTA) is a mycotoxin currently detected in stored animal and human food supplies as well as in human sera worldwide. OTA has diverse toxicological effects; however, the most prominent one is the nephrotoxicity. The present investigation was conducted to determine the molecular aspects of OTA toxicity in cultured human hepatocellular carcinoma cells. With this aim, we have monitored the effects of OTA on (i) cell viability, (ii) heat shock protein expressions as a parameter of protective and adaptive response, (iii) oxidative damage, and (iv) cell death signaling pathway. Our results clearly showed that OTA treatment inhibits cell proliferation, downregulates Hsp 70 and Hsp 27 protein and mRNA levels, and did not induce a significant reactive oxygen species generation. We have also demonstrated a decrease in mitochondrial membrane potential, a cytochrome c release, and an activation of caspase 9 and caspase 3 in response to OTA exposure. Moreover, OTA activates p53 expression, while some of its transcriptional target genes (Bax, Bak, PUMA, and p21) were found to downregulate. According to these data, we concluded that OTA may exert an inhibitory action on the transcriptional process. Besides, oxidative damage is not a major contributor to OTA toxicity. This mycotoxin induces a mitochondrial and caspase-dependent apoptotic cell death, which seems to be mediated by p53 transcriptional independent activities.
(c) 2009 Wiley Periodicals, Inc.
PMID: 19367635 [PubMed - indexed for MEDLINE]
21. Parasitology. 2009 Mar;136(3):273-81. Epub 2009 Jan 21.
Aggravation of pathogenesis mediated by ochratoxin A in mice infected with Trypanosoma brucei rhodesiense.
Kibugu JK, Ngeranwa JJ, Makumi JN, Gathumbi JK, Kagira JM, Mwangi JN, Muchiri MW, Mdachi RE.
Kenya Agricultural Research Institute, Trypanosomiasis Research Centre, P. O. Box 362, Kikuyu, Kenya. email@example.com
Mice fed 1.5 mg ochratoxin A (OTA) per kg body weight and infected with Trypanosoma brucei rhodesiense were compared with trypanosome-infected placebo-fed and uninfected OTA-fed controls. Uninfected OTA-fed mice showed fever, lethargy, facial and eyelid oedemas, mild hepatitis and nephritis, and high survival. Infected placebo-fed controls had mean pre-patent period (PPP) of 3.26 days, lethargy, dyspnoea, fever, facial and scrotal oedema, survival of 33-65 days, reduced red cell counts (RCC: 10.96-6.87x106 cells/microl of blood), packed cell volume (PCV: 43.19-26.36%), haemoglobin levels (Hb: 13.37-7.92 g/dL) and mean corpuscular volume (MCV) of 37.96-41.31 fL, hepatosplenomegaly, generalized oedemas, heart congestion, hepatitis and nephritis. Compared to infected placebo-fed controls, infected OTA-fed mice had significantly (P<0.05) shorter mean PPP (2.58 days), reduced survival (6-47 days), more pronounced fever and dyspnoea. The latter had significantly (P<0.05) reduced RCC (10.74-4.56x106 cells/microl of blood), PCV (43.90-20.78%), Hb (13.06-5.74 g/dL), increased MCV (39.10-43.97 fL), severe generalized oedemas, haemorrhages, congestion, hepatic haemosiderosis, hepatitis, nephritis, endocarditis, pericarditis and exclusively, splenic macrophage and giant cell hyperplasia, expanded red pulp and splenic erythrophagocytosis. It was concluded that OTA aggravated the pathogenesis of T. b. rhodesiense infection in mice, and should therefore be taken into consideration during trypanosomosis control programmes.
PMID: 19154650 [PubMed - indexed for MEDLINE]
22. Mol Nutr Food Res. 2009 Jan;53(1):154-5; author reply 156-7.
Formation of 2'-deoxyguanosine-carbon 8-bound ochratoxin A adduct in rat kidney DNA.
Pfohl-Leszkowicz A, Gabryelski W, Manderville RA.
Comment on Mol Nutr Food Res. 2008 Apr;52(4):472-82.
PMID: 19123177 [PubMed - indexed for MEDLINE]
23. J Nephrol. 2008 Sep-Oct;21(5):673-80.
Balkan endemic nephropathy: a still unsolved puzzle.
Schiller A, Gusbeth-Tatomir P, Pavlovic N, Ferluga D, Spasovski G, Covic A.
Nephrology Clinic, County Hospital and "Victor Babes" University of Medicine and Pharmacy, Timisoara - Romania.
Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial renal disease, occurring in certain regions in 5 countries of the Balkan peninsula. Its etiology is largely unknown, though several hypotheses have been formulated and are discussed in this review. In several cases, etiological hypotheses (e.g., viral, ochratoxin or trace element involvement) are verified only in local endemic areas and can not be confirmed when tested elsewhere. Only certain families in the endemic areas are affected. An exposure of at least 20 years to the unknown factors in the endemic areas seems to be mandatory for the development of the disease, but a genetic predisposition to this disease also seems to be mandatory. Prominent clinical features are severely shrunken kidneys, a more severe anemia relative to the level of renal function, and a slow progression to end-stage renal failure. An international approach to solving the etiological and pathogenetic enigma of BEN is needed in the coming years. It is also time to reevaluate other chronic, slowly progressive tubulointerstitial nephropathies diagnosed elsewhere in the world and to search for possible etiological similarities with BEN.
PMID: 18949721 [PubMed - indexed for MEDLINE]
24. Toxicology. 2008 Dec 5;254(1-2):19-28. Epub 2008 Sep 10.
Different apoptotic pathways induced by zearalenone, T-2 toxin and ochratoxin A in human hepatoma cells.
Bouaziz C, Sharaf El Dein O, El Golli E, Abid-Essefi S, Brenner C, Lemaire C, Bacha H.
Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Rue Avicenne, Monastir 5000, Tunisia.
Mycotoxins, secondary metabolites produced by moulds, have been shown to cause diverse toxic effects in animals and are also suspected of disease causation in humans. The present study compares the molecular mechanisms of the toxicity of zearalenone (ZEN), T-2 toxin and ochratoxin A (OTA) in human hepatoma cells HepG2. The three mycotoxins-induced a caspase-dependent mitochondrial apoptotic pathway. The mitochondrial alterations include: bax relocalisation into the mitochondrial outer membrane, loss of the mitochondrial transmembrane potential, PTPC opening, and cytochrome c (but not AIF) release. In the presence of ZEN and T-2 toxin, reactive oxygen species (ROS) level was highly increased at an early stage even before mitochondrial alterations were observed, whereas OTA-induced only O(2)(-) generation among total ROS. This ROS production appears as a consequence of mitochondrial alterations. HepG2 cell treatment with the p53 inhibitor pifithrin-alpha (PFT) and western blot analysis suggested that both ZEN and OTA, but not T-2 toxin, trigger a p53-dependent apoptotic pathway. These results clearly point to a central role of mitochondria in the apoptotic process induced by ZEN, T-2 toxin and OTA and provide new insights into the molecular mechanisms by which these mycotoxins might promote hepatotoxicty.
PMID: 18834919 [PubMed - indexed for MEDLINE]
25. Toxicol Lett. 2008 Sep;181(1):40-6. Epub 2008 Jul 5.
Differential modification of inflammatory enzymes in J774A.1 macrophages by ochratoxin A alone or in combination with lipopolysaccharide.
Ferrante MC, Raso GM, Bilancione M, Esposito E, Iacono A, Meli R.
Department of Pathology and Animal Health, University of Naples Federico II, Via Delpino 1, 80137 Naples, Italy.
Ochratoxin A (OTA) is a fungal metabolite with controversial immunomodulatory effects. A prolonged in vivo exposure to the mycotoxin may result in impaired immunity and decreased resistance to infections. In the present study, OTA modulation of lipopolysaccharide (LPS)-induced inflammatory process is described in the macrophagic cell line, J774A.1 in order to better understand the mechanisms underlying OTA immunotoxicity. OTA (30 nM-100 microM) induces a time and concentration dependent cytotoxic effect, increased when cells were co-stimulated with LPS (100 ng/ml), a concentration that alone did not modify the cellular viability. Moreover, OTA (3 microM) alone induces a significant increase in cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, while at the highest concentration (10 microM) a reduced expression of both enzymes was shown, consistently with the mycotoxin cytotoxic profile. The role of nuclear factor-kB (NF-kB) in the mycotoxin effect was also demonstrated. Conversely, when cells were co-stimulated with LPS, OTA showed a concentration-dependent reduction of COX-2 and iNOS expression and their respective metabolites (PGE(2) and NO). These results confirm the pro-inflammatory role of OTA by itself, and demonstrate the impaired capability of OTA-treated macrophages to respond properly to noxious stimuli, such as LPS, mimicking the environmental co-exposure to both compounds.
PMID: 18647641 [PubMed - indexed for MEDLINE]
26. World Health Organ Tech Rep Ser. 2007;(947):1-225, back cover.
Evaluation of certain food additives and contaminants.
Joint FAO/WHO Expert Committee on Food Additives, Bend J, Bolger M, Knaap AG, Kuznesof PM, Larsen JC, Mattia A, Meylan I, Pitt JI, Resnik S, Schlatter J, Vavasour E, Rao MV, Verger P, Walker R, Wallin H, Whitehouse B, Abbott PJ, Adegoke G, Baan R, Baines J, Barlow S, Benford D, Bruno A, Charrondiere R, Chen J, Choi M, DiNovi M, Fisher CE, Iseki N, Kawamura Y, Konishi Y, Lawrie S, Leblanc JC, Leclercq C, Lee HM, Moy G, Munro IC, Nishikawa A, Olempska-Beer Z, de Peuter G, Pronk ME, Renwick AG, Sheffer M, Sipes IG, Tritscher A, Soares LV, Wennberg A, Williams GM.
Department of Pathology, Siebens-Drake Medical Research Institute, Schulich of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The Committee also evaluated the risk posed by two food contaminants, with the aim of advising on risk management options for the purpose of public health protection. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular flavouring agents) and contaminants. A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (acidified sodium chlorite, asparaginase from Aspergillus oryzae expressed in Aspergillus oryzae, carrageenan and processed Eucheuma seaweed, cyclotetraglucose and cyclotetraglucose syrup, isoamylase from Pseudomonas amyloderamosa, magnesium sulfate, phospholipase A1 from Fusarium venenatum expressed in Aspergillus oryzae, sodium iron(III) ethylenediaminetetraacetic acid (EDTA) and steviol glycosides); eight groups of related flavouring agents (linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; aliphatic acyclic and alicyclic terpenoid tertiary alcohols and structurally related substances; simple aliphatic and aromatic sulfides and thiols; aliphatic acyclic dials, trials and related substances; aliphatic acetals; sulfur-containing heterocyclic compounds; aliphatic and aromatic amines and amides; and aliphatic alicyclic linear alpha, beta -unsaturated di- and trienals and related alcohols, acids and esters); and two food contaminants (aflatoxin and ochratoxin A). Specifications for the following food additives were revised: maltol and ethyl maltol, nisin preparation, pectins, polyvinyl alcohol, and sucrose esters of fatty acids. Specifications for the following flavouring agents were revised: maltol and ethyl maltol, maltyl isobutyrate, 3-acetyl-2,5-dimethylfuran and 2,4,5-trimethyl-delta-oxazoline (Nos 1482, 1506 and 1559), and monomenthyl glutarate (No. 1414), as well as the method of assay for the sodium salts of certain flavouring agents. Annexed to the report are tables summarizing the Committee's recommendations for intakes and toxicological evaluations of the food additives and contaminants considered.
PMID: 18551832 [PubMed - indexed for MEDLINE]
27. Commun Agric Appl Biol Sci. 2007;72(2):327-32.
Low levels of ochratocin A in wines from Piedmont.
Spadaro D, Ciavorella A, Lore A, Garibaldi A, Gullino ML.
DiVaPRA-Plant Pathology, University of Torino Via L. Da Vinci 44, IT-10095 Grugliasco, Italy.
Ochratoxin A (OTA) is a mycotoxin mainly produced by a number of species of Aspergillus, commonly found in warm and tropical climates. OTA poses risks for the human health because of its nephrotoxic, teratogenic, immunotoxic and neurotoxic activity. The mycotoxin, classified as possible human carcinogen (Group 2B) by the IARC, naturally occurs in a wide range of foods, including wine, where the main producer is A. carbonarius. The aim of this work was the validation of a procedure for the analysis of OTA in Piedmontese red and white wines produced after vintage 2003 and 2004, in relationship with the limit of 2.0 microg l(-1) introduced by European Union for wine, must or grape juice (Regulation CE N. 123/2005). An analytical method based on immunoaffinity column (IAC) for clean-up and liquid chromatography with fluorescence detection (LC-FLD) was used to determine the occurrence of OTA in wines. Detection limit (LOD) and quantification Limit (LOQ) were 7.18 pg/ml and 9.31 pg/ml based on statistical method (IUPAC). Average recoveries of OTA from wine samples spiked at levels from 0.1 to 10 ng/ml ranged from 90.8% to 92.4%, with relative standard deviations (RSDs) between 2.64 and 2.71%. Repeatability limit was 8.73 pg/ml for samples spiked with 0.1 ng/ml of OTA. Ninety-one Denomination of Controlled Origin (DOC) wines were analysed, including 41 Barbera (red), 38 Dolcetto (red), and 16 white wines, such as Erbaluce, Cortese and Roero Arneis. The study focused on wines commercialized in Italian supermarkets and wine shops. The white wines resulted, as expected, less contaminated than the red ones. Wines produced after vintage 2003, a season particularly conducive to the growth of A. carbonorius, contained higher levels of OTA than the wines produced in 2004. The samples, resulting positive, contained a concentration of OTA highly inferior to the threshold limits introduced by the European Union. The sample of the highest level of OTA was a Dolcetto produced in 2004, with 1.10 ng/ml of mycotoxin.
PMID: 18399460 [PubMed - indexed for MEDLINE]
28. Toxicol Sci. 2008 Jun;103(2):371-81. Epub 2008 Feb 27.
Evaluation of putative biomarkers of nephrotoxicity after exposure to ochratoxin a in vivo and in vitro.
Rached E, Hoffmann D, Blumbach K, Weber K, Dekant W, Mally A.
Department of Toxicology, University of Würzburg, Würzburg D-97078, Germany.
The kidney is one of the main targets of xenobiotic-induced toxicity, but early detection of renal damage is difficult. Recently, several novel biomarkers of nephrotoxicity have been identified by transcription profiling, including kidney injury molecule-1 (Kim-1), lipocalin-2, tissue inhibitor of metalloproteinases-1 (Timp-1), clusterin, osteopontin (OPN), and vimentin, and suggested as sensitive endpoints for acute kidney injury in vivo. However, it is not known if these cellular marker molecules may also be useful to predict chronic nephrotoxicity or to detect nephrotoxic effects in vitro. In this study, a panel of new biomarkers of renal toxicity was assessed via quantitative real-time PCR, immunohistochemistry, and immunoblotting in rats treated with the nephrotoxin ochratoxin A (OTA) for up to 90 days and in rat proximal tubule cells (NRK-52E) treated with OTA in vitro. Repeated administration of OTA to male F344/N rats for 14, 28, or 90 days resulted in a dose- and time-dependent increase in the expression of Kim-1, Timp-1, lipocalin-2, OPN, clusterin, and vimentin. Changes in gene expression were found to correlate with the progressive histopathological alterations and preceded effects on traditional clinical parameters indicative of impaired kidney function. Induction of Kim-1 messenger RNA expression was the earliest and most prominent response observed, supporting the use of this marker as sensitive indicator of chronic kidney injury. In contrast, no significant increase in the expression of putative marker genes and proteins were evident in NRK-52E cells after exposure to OTA for up to 48 h, suggesting that they may not be suitable endpoints for sensitive detection of nephrotoxic effects in vitro.
PMID: 18308701 [PubMed - indexed for MEDLINE]
29. Toxicol Appl Pharmacol. 2008 Apr 1;228(1):84-92. Epub 2007 Nov 22.
Both direct and indirect effects account for the pro-inflammatory activity of enteropathogenic mycotoxins on the human intestinal epithelium: stimulation of interleukin-8 secretion, potentiation of interleukin-1beta effect and increase in the transepithelial passage of commensal bacteria.
Maresca M, Yahi N, Younès-Sakr L, Boyron M, Caporiccio B, Fantini J.
Laboratoire des Interactions Moléculaires et Systèmes Membranaires (IMSM), Université Paul Cézanne, Faculté des Sciences et Techniques de Saint-Jérôme, Avenue Escadrille Normandie-Niemen, 13397, Marseille Cedex 20, France.
Mycotoxins are fungal secondary metabolites responsible of food-mediated intoxication in animals and humans. Deoxynivalenol, ochratoxin A and patulin are the best known enteropathogenic mycotoxins able to alter intestinal functions resulting in malnutrition, diarrhea, vomiting and intestinal inflammation in vivo. Although their effects on intestinal barrier and transport activities have been extensively characterized, the mechanisms responsible for their pro-inflammatory effect are still poorly understood. Here we investigated if mycotoxin-induced intestinal inflammation results from a direct and/or indirect pro-inflammatory activity of these mycotoxins on human intestinal epithelial cells, using differentiated Caco-2 cells as model and interleukin 8 (IL-8) as an indicator of intestinal inflammation. Deoxynivalenol was the only mycotoxin able to directly increase IL-8 secretion (10- to 15-fold increase). We also investigated if these mycotoxins could indirectly stimulate IL-8 secretion through: (i) a modulation of the action of pro-inflammatory molecules such as the interleukin-1beta (IL-1beta), and/or (ii) an increase in the transepithelial passage of non-invasive commensal Escherichia coli. We found that deoxynivalenol, ochratoxin A and patulin all potentiated the effect of IL-1beta on IL-8 secretion (ranging from 35% to 138% increase) and increased the transepithelial passage of commensal bacteria (ranging from 12- to 1544-fold increase). In addition to potentially exacerbate established intestinal inflammation, these mycotoxins may thus participate in the induction of sepsis and intestinal inflammation in vivo. Taken together, our results suggest that the pro-inflammatory activity of enteropathogenic mycotoxins is mediated by both direct and indirect effects.
PMID: 18308354 [PubMed - indexed for MEDLINE]
30. Toxicol Appl Pharmacol. 2008 Jun 1;229(2):227-31. Epub 2008 Jan 26.
Ochratoxin A inhibits the production of tissue factor and plasminogen activator inhibitor-2 by human blood mononuclear cells: another potential mechanism of immune-suppression.
Rossiello MR, Rotunno C, Coluccia A, Carratù MR, Di Santo A, Evangelista V, Semeraro N, Colucci M.
Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari, Policlinico, Piazza G. Cesare 11, 70124 Bari, Italy.
The mycotoxin ochratoxin A (OTA), an ubiquitous contaminant of food products endowed with a wide spectrum of toxicity, affects several functions of mononuclear leukocytes. Monocytes/macrophages play a major role in fibrin accumulation associated with immune-inflammatory processes through the production of tissue factor (TF) and plasminogen activator inhibitor 2 (PAI-2). We studied the effect of OTA on TF and PAI-2 production by human blood mononuclear cells (MNC). The cells were incubated for 3 or 18 h at 37 degrees C with non toxic OTA concentrations in the absence and in the presence of lipopolysaccharide (LPS) or other inflammatory agents. TF activity was measured by a one-stage clotting test. Antigen assays were performed by specific ELISAs in cell extracts or conditioned media and specific mRNAs were assessed by RT-PCR. OTA had no direct effect on TF and PAI-2 production by MNC. However, OTA caused a dose-dependent reduction in LPS-induced TF (activity, antigen and mRNA) and PAI-2 (antigen and mRNA) production with >85% inhibition at 1 mug/ml. Similar results were obtained when monocyte-enriched preparations were used instead of MNC. TF production was also impaired by OTA (1 mug/ml) when MNC were stimulated with phorbol myristate acetate (98% inhibition), IL-1beta (83%) or TNF-alpha (62%). The inhibition of TF and PAI-2 induction might represent a hitherto unrecognized mechanism whereby OTA exerts immunosuppressant activity.
PMID: 18289624 [PubMed - indexed for MEDLINE]
31. Arch Toxicol. 2008 Apr;82(4):247-55. Epub 2007 Sep 19.
Cytotoxicity and apoptosis induced by fumonisin B(1), beauvericin and ochratoxin A in porcine kidney PK15 cells: effects of individual and combined treatment.
Klarić MS, Rumora L, Ljubanović D, Pepeljnjak S.
Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia. firstname.lastname@example.org
The objective of this study was to determine individual and combined effects of fumonisin B(1) (FB(1)), beauvericin (BEA) and ochratoxin A (OTA) on porcine kidney epithelial PK15 cell survival by measuring lactate dehydrogenase (LDH) activity, apoptotic index and caspase-3 activity. Cells were treated with 0.05, 0.5 and 5 microg/ml of each mycotoxin or with the combinations of two or all three mycotoxins for 24 and 48 h. Changes in LDH and caspase-3 activity, and in apoptotic index showed that the cytotoxic and apoptotic effects of these mycotoxins were concentration- and time- dependent. Significant increase of LDH activity was observed after 48 h of exposure to the highest concentration of FB(1) (45%), BEA (84%) and OTA (77%), as compared to control. OTA increased caspase-3 activity after 24 h of treatment with 0.5 mug/mL (84%), while BEA (319%) and FB(1) (419%) significantly affected this enzyme activity after 48 h (P < 0.05). Increase of caspase-3 activity preceded significant morphological apoptotic changes, which were detected after 48 h of exposure to a single toxin. Combined treatment with FB(1), BEA and OTA resulted mostly in additive effects on LDH activity, and additive and synergistic effects on caspase-3 activity and apoptotic index.
PMID: 17879085 [PubMed - indexed for MEDLINE]
32. Exp Toxicol Pathol. 2007 Oct;59(2):85-95. Epub 2007 Jul 16.
DNA ploidy distribution in renal tumours induced in male rats by dietary ochratoxin A.
Brown AL, Odell EW, Mantle PG.
Department of Oral Pathology, Guy's Hospital, London, UK.
DNA ploidy distribution, measured in experimental renal tumours that occurred in twelve ageing male Fischer rats derived from carcinogenicity experiments on ochratoxin A (OTA) in response to chronic dietary exposure, was diploid in all renal adenomas and aneuploid in all carcinomas, correlating with their typical organised and disorganised histopathology, respectively. Aneuploidy was also detected in renal tissue in which karyomegaly, induced by OTA, was analogous to that caused by the fungus Penicillium polonicum. Thus, the experimental rat renal carcinoma could arise within an adenoma directly from certain persistent karyomegalic tubular epithelial cells long after their particular genetic damage has been caused during a protracted period of OTA insult.
PMID: 17629687 [PubMed - indexed for MEDLINE]
33. Chem Res Toxicol. 2007 Jul;20(7):1031-7. Epub 2007 Jun 14.
Ochratoxin A-induced mutagenesis in mammalian cells is consistent with the production of oxidative stress.
Palma N, Cinelli S, Sapora O, Wilson SH, Dogliotti E.
Department of Environment and Primary Prevention, Istituto Superiore di Sanita', Viale Regina Elena 299, 00161 Rome, Italy.
Ochratoxin A (OTA) is a widespread mycotoxin in food and a powerful nephrocarcinogen in rats. The mutagenicity of OTA has been extensively investigated but with conflicting results, thus leaving open the mechanistic question for OTA carcinogenicity. Here, we examined the mutagenicity of OTA by using well-standardized mutation assays such as the hypoxanthine-guanine phosphoribosyltransferase (HPRT) assay in Chinese hamster V79 cells and the thymidine kinase assay in mouse lymphoma LY5178 cells. OTA-induced HPRT mutations were characterized at the molecular level. In V79 cells, OTA produced a dose- and time-related decrease in cell number as a consequence of the transitory cytostatic effect mediated by G2/M cell cycle arrest. In both mutation assays, OTA was weakly mutagenic and this effect was independent of biotransformation. OTA-induced mutations were characterized by point mutations (48%) and a lack of a detectable reverse-transcription polymerase chain reaction product (52%). The pattern of OTA-induced point mutations was similar to that of spontaneous mutants, suggesting that OTA induced an increase of the endogenous oxidative metabolism but not covalent DNA adducts. Our data support a model where OTA is mutagenic via oxidative DNA damage induction.
PMCID: PMC2367102 PMID: 17567156 [PubMed - indexed for MEDLINE]
34. Cancer Res. 2007 May 1;67(9):4052-68.
Carcinogen-specific gene expression profiles in short-term treated Eker and wild-type rats indicative of pathways involved in renal tumorigenesis.
Stemmer K, Ellinger-Ziegelbauer H, Ahr HJ, Dietrich DR.
Human and Environmental Toxicology, University of Konstanz, Konstanz, Germany.
Eker rats heterozygous for a dominant germline mutation in the tuberous sclerosis 2 (Tsc2) tumor suppressor gene were used as a model to study renal carcinogenesis. Eker and corresponding wild-type rats were exposed to genotoxic aristolochic acid (AA) or non-genotoxic ochratoxin A (OTA) to elucidate early carcinogen-specific gene expression changes and to test whether Eker rats are more sensitive to carcinogen-induced changes in gene expression. Male Eker and wild-type rats were gavaged daily with AA (10 mg/kg body weight) or OTA (210 microg/kg body weight). After 1, 3, 7, and 14 days of exposure, renal histopathology, tubular cell proliferation, and Affymetrix gene expression profiles from renal cortex/outer medulla were analyzed. AA-treated Eker and wild-type rats were qualitatively comparable in all variables assessed, suggesting a Tsc2-independent mechanism of action. OTA treatment resulted in slightly increased cortical pathology and significantly elevated cell proliferation in both strains, although Eker rats were more sensitive. Deregulated genes involved in the phosphatidylinositol 3-kinase-AKT-Tsc2-mammalian target of rapamycin signaling, among other important genes prominent in tumorigenesis, in conjunction with the enhanced cell proliferation and presence of preneoplastic lesions suggested involvement of Tsc2 in OTA-mediated toxicity and carcinogenicity, especially as deregulation of genes involved in this pathway was more prominent in the Tsc2 mutant Eker rat.
PMID: 17483316 [PubMed - indexed for MEDLINE]
35. J Food Prot. 2007 Apr;70(4):975-80.
Penicillium populations in dry-cured ham manufacturing plants.
Battilani P, Pietri VA, Giorni P, Formenti S, Bertuzzi T, Toscani T, Virgili R, Kozakiewicz Z.
Institute of Entomology and Plant Pathology, Università Cattolica del Sacro Cuore, Via Emilia Parmense, 84, 29100 Piacenza, Italy. email@example.com
Seven ham manufacturing plants were sampled for 1 year to assess the mycoflora present in the air and on hams, with special attention given to potential mycotoxin producers. Temperature and relative humidity were recorded in the ripening rooms. Maturing rooms held hams from 2 to 3 through 6 to 7 ripening months, and aging rooms held hams for the following 6 to 7 months, until the 14-month ripening point, when they were ready for the market. Mean temperatures and relative humidities registered during the study were 14.9 degrees C and 62.4%, respectively, in maturing rooms and 16.3 degrees C and 57.6% in aging rooms. Aspergilli and penicillia, potential mycotoxin producers, were isolated in all the plants from the air and the ham. Aspergilli represented 5% of the isolates, while penicillia were largely dominant, with Penicillium nalgiovense being the most represented species (around 60% of the penicillia), followed by Penicillium nordicum, with 10 and 26% of the penicillia isolated, respectively, from the air or the ham. Ochratoxin A production ability, checked in vitro at 250C, was observed in 50% of the P. nordicum isolates obtained both from the air and the ham. Air and ham surface contamination by penicillia was greater in the ripening rooms, where higher temperatures were registered. A certain correlation was also observed between air and ham surface contamination. On the basis of this study, P. nordicum, the ochratoxin A producer that is notable on proteinaceous substrates, is normally present in ham manufacturing plants in Italy, even though not a dominant species. Further studies are necessary to clarify and ensure if dry-curing conditions minimize the potential risk of ochratoxin A formation in the product.
PMID: 17477269 [PubMed - indexed for MEDLINE]
36. Int J Toxicol. 2007 Jan-Feb;26(1):81-7.
Protective role of melatonin and coenzyme Q10 in ochratoxin A toxicity in rat liver and kidney.
Sutken E, Aral E, Ozdemir F, Uslu S, Alatas O, Colak O.
Department of Biochemistry, Medical School, Osmangazi University, Eskisehir, Turkey.
Melatonin (MEL) and coenzyme Q10 (CoQ10) both display antioxidant and free radical scavenger properties. In the present study, the effect of MEL and CoQ10 on the oxidative stress and fibrosis induced by ochratoxin A (OTA) administration in rats was investigated. Rats were divided into five equal groups, each consisting of seven rats: (1) controls; (2) OTA-treated rats (289 microg/kg/day); (3) OTA+MEL-treated rats (289 microg/kg/day OTA + 10 mg/kg/day MEL); and (4) OTA+CoQ10-treated rats (289 microg/kg/day OTA + 1 mg/100 g/day body weight (bw) CoQ10). After 4 weeks of treatment, the level of malondialdehyde (MDA), glutathione peroxidase (GPx), and hydroxyproline (Hyp) were measured in the homogenates of liver and kidney. In the OTA-treated group, the levels of MDA and Hyp in both liver and kidney were significantly increased when compared with the levels of control, whereas GPx activities decreased. In OTA+MEL-treated rats, the levels of MDA and Hyp in both liver and kidney were significantly decreased when compared with the levels of OTA-treated rats; however; GPX activities increased. In the OTA+CoQ10-treated group, the levels of MDA and Hyp were decreased when compared with the levels of OTA-treated rats, whereas GPx activities increased. In the OTA+CoQ10-treated group, the levels of MDA, Hyp, and GPx were not significantly changed in kidney when compared with OTA-treated group. MEL has a protective effect against OTA toxicity through an inhibition of the oxidative damage and fibrosis both liver and kidney. Although CoQ10 has protective effect against OTA toxicity in liver tissue, it has no effect in kidney tissue.
PMID: 17365150 [PubMed - indexed for MEDLINE]
37. Toxicol Sci. 2007 Jun;97(2):288-98. Epub 2007 Mar 6.
Ochratoxin A: 13-week oral toxicity and cell proliferation in male F344/n rats.
Rached E, Hard GC, Blumbach K, Weber K, Draheim R, Lutz WK, Ozden S, Steger U, Dekant W, Mally A.
Department of Toxicology, University of Würzburg, Würzburg, Germany.
Ochratoxin A (OTA) is nephrotoxic and a potent renal carcinogen. Male rats are most susceptible to OTA toxicity, and chronic administration of OTA (70 and 210 microg/kg bw) for 2 years has been shown to induce high incidences of adenomas and carcinomas arising from the straight segment of the proximal tubule epithelium. In contrast, treatment with a lower dose of 21 microg/kg bw did not result in increased tumor rates, suggesting a nonlinear dose response for renal tumor formation by OTA. Since the mechanism of OTA carcinogenicity is still largely unknown, this study was conducted to investigate early functional and pathological effects of OTA and to determine if sustained stimulation of renal cell proliferation plays a role. Male F344/N rats were treated with OTA for up to 13 weeks under conditions of the National Toxicology Program (NTP) bioassay. Cell proliferation in the renal cortex and outer stripe of the outer medulla (OSOM) was determined using bromodeoxyuridine incorporation and immunohistochemistry. Histopathological examination showed renal alterations in mid- and high-dose-treated animals involving single-cell death and prominent nuclear enlargement within the straight proximal tubules. Treatment with OTA at doses of 70 and 210 microg/kg bw led to a marked dose- and time-dependent increase in renal cell proliferation, extending from the medullary rays into the OSOM. No effects were evident in kidneys of low-dose-treated animals or in the liver, which is not a target for OTA carcinogenicity. A no observed effect level in this study was established at 21 microg/kg bw, correlating with the dose in the NTP 2-year bioassay that did not produce renal tumors. The apparent correlation between enhanced cell turnover and tumor formation induced by OTA indicates that stimulation of cell proliferation may play an important role in OTA carcinogenicity and provides further evidence for an epigenetic, thresholded mechanism.
PMID: 17344223 [PubMed - indexed for MEDLINE]
38. Toxicology. 2007 Mar 22;232(1-2):57-67. Epub 2006 Dec 15.
Long-term effects of ochratoxin A on fibrosis and cell death in human proximal tubule or fibroblast cells in primary culture.
Schwerdt G, Holzinger H, Sauvant C, Königs M, Humpf HU, Gekle M.
Physiologisches Institut, Universität Würzburg, Röntgenring 9, D-97070 Würzburg, Germany. firstname.lastname@example.org
Ochratoxin A (OTA) is a mycotoxin produced by several fungi which grow on human food source material. Consumption of OTA is almost unavoidable. The consumption leads to low but detectable amounts of OTA in human blood. Risk assessment of OTA is based on studies performed either in animals or cultured cells. So far, mainly cell lines of different origin were used. To be as close as possible to the situation in humans with respect to the experimental setup, we studied the effect of OTA in human proximal tubule cells (RPTEC) and human fibroblasts in primary culture. OTA was administered at concentrations ranging from 0.3 nmol/l up to 10 micromol/l for time periods up to 14 days. Apoptotic and necrotic cell death, collagen I, III, IV and fibronectin secretion as well as NF-kappaB activation were studied. Under our experimental conditions OTA exerted comparable effects on caspase-3 activity and necrosis in both cell types, however RPTEC were more sensitive (order of 10). Surprisingly, very low concentrations of OTA (0.3-10nM) led to cell hypertrophy during prolonged exposure (14 days). RPTEC but not fibroblasts responded with an increase of NF-kappaB activity and collagen III as well as fibronectin secretion underlining the profibrotic action of OTA in the kidney. Collagen I and IV secretion was only slightly changed. The results presented here give good reasons to re-asses the risk of OTA consumption leading to low blood concentrations which have so far been considered harmless.
PMID: 17218050 [PubMed - indexed for MEDLINE]
39. Mycopathologia. 2007 Jan;163(1):21-30.
Ochratoxin A and citrinin nephrotoxicity in New Zealand White rabbits: an ultrastructural assessment.
Kumar M, Dwivedi P, Sharma AK, Singh ND, Patil RD.
Mycotic and Mycotoxic Disease Laboratory, Division of Pathology, Indian Veterinary Research Institute, IVRI Road, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India.
In the present investigation, ochratoxin A (OTA) (0.75 mg/kg feed) and citrinin (CIT) (15 mg/kg feed) were fed alone and in combination to young growing New Zealand White rabbits for 60 days to evaluate renal ultrastructural alterations. The severity and intensity of renal ultrastructural changes varied with the type of the treatment, and predominant and consistent lesions were recorded in the proximal convoluted tubule (PCT) lining cells. The significant changes in mitochondria, the most affected cell organelle in all the treatment groups, included mitochondrial disintegration and distortion, pleomorphism, cluster formation and misshapen appearance such as signet ring, dumbbell, cup and U shapes. Intra-cisternal sequestrations of involuting mitochondria, and thickening of basal layer of PCT epithelial cells with partial detachment, were the characteristic features observed in OTA and combination treatments. CIT treatment revealed crenated nucleus, loss of nucleolus, depletion of cytoplasmic organelles, mitochondrial pleomorphism, nuclear fragmentation, uniform folding of cell membrane and cytoplasmic vacuolations in the PCTs. Focal thickening of the glomerular basement membrane and degeneration of endothelial cells were the prominent alterations in the glomeruli in OTA and combination treatments. Distal convoluted tubules were unaffected in CIT treatment, however, mild to moderate lesions were observed in OTA and combination treated rabbits. It may be concluded that on simultaneous exposure, CIT potentiated the toxic effects of OTA on renal ultrastructure.
PMID: 17216328 [PubMed - indexed for MEDLINE]
40. Vet Rec. 2006 Dec 2;159(23):761-8.
Survey of pigs' kidneys with lesions consistent with PMWS and PDNS and ochratoxicosis. Part 2: pathological and histological findings.
Gresham A, Done S, Livesey C, MacDonald S, Chan D, Sayers R, Clark C, Kemp P.
Veterinary Laboratories Agency - Bury St Edmunds, Rougham Hill, Bury St Edmunds, Suffolk.
One thousand condemned pigs' kidneys were collected in February 2002 from two pig abattoirs in England to assess the lesions due to postweaning multisystemic wasting syndrome (pmws) and porcine dermatitis and nephropathy syndrome (pdns) and the possible contribution of ochratoxicosis; 174 of the kidneys were pale, 295 were swollen and 81 were abnormally firm with the gross appearance of fibrosis. The main macroscopic finding was the presence of multifocal pale cortical lesions, observed in 446 of the kidneys, and there were large cysts in 266 of them. Histopathological lesions of non-suppurative tubulointerstitial nephritis, with degeneration and fibrosis of renal tubules, were identified in 213 of 250 (85.2 per cent) of the kidneys examined. These lesions were consistent with those reported in cases of pmws and pdns. The tubular degeneration and fibrosis were also consistent with ochratoxicosis. A higher mean concentration of ochratoxin A was significantly (P=0.020) associated with the presence of multifocal pale cortical lesions consistent with ochratoxicosis, but a causal relationship was not confirmed because histochemistry was not used to detect ochratoxin in the lesions directly. There was no significant correlation between the microscopic lesions and the concentration of ochratoxin. The degenerative lesions may have been caused by previous exposure to ochratoxin that had subsequently been excreted, but the microscopic lesions also included non-suppurative interstitial nephritis, which was unlikely to have been caused by ochratoxicosis.
PMID: 17142623 [PubMed - indexed for MEDLINE]
41. Vet Rec. 2006 Nov 25;159(22):737-42.
Survey of pigs' kidneys with lesions consistent with PMWS and PDNS and ochratoxicosis. Part 1: concentrations and prevalence of ochratoxin A.
Gresham A, Done S, Livesey C, Macdonald S, Chan D, Sayers R, Clark C, Kemp P.
Veterinary Laboratories Agency, Bury St Edmunds, Rougham Hill, Bury St Edmunds, Suffolk.
One thousand condemned pigs' kidneys were collected in February 2002 from two pig abattoirs in England to assess the possible contribution of ochratoxicosis to postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS); 250 of the kidneys with macroscopic lesions consistent with nephrosis/nephritis (pale or white cortical lesions) were selected, and the concentration of ochratoxin A was measured in samples of renal cortex by high-performance liquid chromatography (HPLC). Low concentrations were detected in 230 (92 per cent) of the kidneys tested, and in 41 (16.4 per cent) of them the concentration was below the limit of quantification of 0.2 microg/kg. In 187 (74.8 per cent) of the kidneys, the concentration was more than 0.2 microg/kg, and the highest concentration detected was 2.3 microg/kg. The mean (sd) concentration was 0.31 (0.33) microg/kg. The identification of ochratoxin A was confirmed by mass spectrometry. The concentrations of ochratoxin A did not exceed the threshold assessed by the Food Standards Agency to be safe for human food.
PMID: 17127757 [PubMed - indexed for MEDLINE]
42. Toxicol In Vitro. 2007 Feb;21(1):72-80. Epub 2006 Sep 6.
Effects of repeated ochratoxin exposure on renal cells in vitro.
Heussner AH, O'Brien E, Dietrich DR.
Environmental Toxicology, University of Konstanz, P.O. Box X-918, 78457 Konstanz, Germany.
In the present study an in vitro model of subchronic repeated exposure to OTA and OTB was employed to generate ochratoxin-derived subpopulations of human and porcine proximal tubular cells (HKC, IHKE, PKC, LLC-PK1). These cell subpopulations were subsequently used to investigate effects on cell proliferation rates, expression of marker proteins (cytokeratins, vimentin) and the acute cytotoxicity of OTA and OTB (MTT reduction, neutral red uptake, cell number). The hypothesis was tested whether repeated exposure at moderate concentrations of these toxins could provide for a reduced sensitivity of selected cell subpopulations to subsequent toxin exposure. Despite the observed increased cell population doubling times and the reduced sensitivity toward OTA and OTB exposure of some cell types, with the exception of the primary human epithelial cells, no overt changes in the expression of cytokeratin and vimentin could be determined. The presented data, however suggest that repeated exposure of renal epithelial cells to ochratoxins A or B will provide for a subpopulation of cells with reduced ochratoxin-sensitivity and alterations in growth characteristics.
PMID: 17045452 [PubMed - indexed for MEDLINE]
43. Toxicology. 2006 Aug 15;225(2-3):214-24. Epub 2006 Jun 10.
Early cytotoxic effects of ochratoxin A in rat liver: a morphological, biochemical and molecular study.
Gagliano N, Donne ID, Torri C, Migliori M, Grizzi F, Milzani A, Filippi C, Annoni G, Colombo P, Costa F, Ceva-Grimaldi G, Bertelli AA, Giovannini L, Gioia M.
Department of Human Morphology-LITA Segrate, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy. email@example.com
We characterized the overall early effect of chronic ochratoxin A (OTA) treatment on rat liver, analyzing different aspects related to: (i) fibrosis, by measuring collagen content and turnover, and alpha-smooth muscle actin (alphaSMA); (ii) oxidative stress and stress response, by analyzing protein carbonylation, superoxide dismutase (SOD) and heat shock protein (HSP70) gene expression; (iii) the possible tumor promoter effect, evaluating cadherin and connexin (CX) mRNA levels. Light microscopy analysis showed no histological differences in OTA-treated and control (CT) rats. Collagen content, determined by computer analysis of Sirius red-stained liver sections, was similar in both groups. In liver homogenates COL-I, COL-III, TIMP-1 and TGF-beta1 mRNA levels and alphaSMA were unaffected by OTA. Matrix metalloproteinase (MMP)-1, MMP-2 and MMP-9 protein levels were also similar in the two groups. Protein carbonylation, a marker of severe oxidative stress, was not evident in the homogenates of OTA-treated livers; superoxide dismutase (SOD) mRNA tended to be lower and HSP70 was strongly down-regulated. OTA reduced E-cadherin and DSC-2 transcription, and down-regulated liver CX26, CX32 and CX43. In conclusion, these in vivo results show that OTA-induced liver injury involves a reduction in the ability to counterbalance oxidative stress, maybe leading to altered gap junction intercellular communication and loss of cell adhesion and polarity. This suggests that mild oxidative damage might be a key factor, in combination with other cytotoxic effects, in triggering the promotion of liver tumors after exposure to OTA.
PMID: 16857307 [PubMed - indexed for MEDLINE]
44. Reprod Toxicol. 2006 Nov;22(4):679-87. Epub 2006 Jun 14.
Critical period and minimum single oral dose of ochratoxin A for inducing developmental toxicity in pregnant Wistar rats.
Patil RD, Dwivedi P, Sharma AK.
Division of Pathology, Indian Veterinary Research Institute, Izatnagar 243 122, Uttar Pradesh, India. firstname.lastname@example.org
Ochratoxin A (OTA), a potent in vivo teratogen, has been tested in various laboratory animal species. Present investigation was conducted to determine critical dose and critical time for the developmental toxicity of OTA in pregnant Wistar rats after single oral dose administration. OTA at different graded dose levels (2-4 mg/kg body weight) and at different gestation days (6-15), caused variable developmental defects in developing fetuses. OTA at 2.75 mg/kg body weight, dissolved in 0.1 M sodium bicarbonate (vehicle) and administered by oral intubation as a single dose on one of the gestational days 6-15, caused significant maternal toxicity in the dams and various gross, visceral and skeletal anomalies in the fetuses. The major gross malformations were external hydrocephaly, incomplete closure of skull and omphalocele. Internal hydrocephaly, microphthalmia, enlarged renal pelvis and renal hypoplasia were the main internal soft tissue anomalies. Major skeletal defects were developmental defects in skull bones, sternebrae, vertebrae and ribs. The gestational days 6 and 7 were found to be the most critical for the induction of teratogenicity in rats. Single oral dose of 2.75 mg/kg body weight OTA was found to be the minimum effective teratogenic dose in pregnant Wistar rats.
PMID: 16781114 [PubMed - indexed for MEDLINE]
45. Int J Food Microbiol. 2006 Sep 1;111 Suppl 1:S2-4. Epub 2006 May 19.
European research on ochratoxin A in grapes and wine.
Battilani P, Magan N, Logrieco A.
Institute of Enthomology and Plant Pathology, Università Cattolica del Sacro Cuore, Via E. Parmense 84, 29100 Piacenza, Italy. email@example.com
European wine production represents about 70% of world production and thus is an important export commodity. Ochratoxin A (OTA) was first detected as a wine contaminant in 1996 and the role of Aspergillus section Nigri and A. carbonarius in OTA production discovered in Europe in 1999. Subsequently Europe-wide surveys have shown that A. carbonarius is predominantly responsible for OTA contamination of grapes, wine and vine fruits. Analyses of wine samples throughout Europe have shown that there is a gradient in OTA concentration with a decrease from red, to rose and to white wines. The latitude of production is an important factor in determining risk from OTA contamination. Some geographic regions in Southern Europe are more prone to contamination with the toxigenic species and OTA. Ochratoxin A has also been found in much higher concentrations (max. 53 mug/kg) in dried vine fruit than in wine suggesting that A. carbonarius can dominate the drying vine fruit ecosystem. There is a significant lack of knowledge in Europe on conducive climatic conditions preharvest and their relationship with levels of risk from OTA contamination in grapes and their fate in wine production. This needs to be integrated with cultivation system to maximise the prevention of OTA entering this food chain.
PMID: 16712998 [PubMed - indexed for MEDLINE]
46. Int J Food Microbiol. 2006 Sep 1;111 Suppl 1:S1. Epub 2006 May 19.
Black aspergilli and ochratoxin A in grapes and wine. Introductory note.
Battilani P, Logrieco A, Magan N.
Universita Cattolica del Sacro Cuore, Institute of Enthomology and Plant Pathology, Via E. Parmense 84, 29100, Piacenza, Italy. firstname.lastname@example.org
PMID: 16712996 [PubMed - indexed for MEDLINE]
47. Int J Environ Res Public Health. 2005 Apr;2(1):186-93.
How much should we involve genetic and environmental factors in the risk assessment of mycotoxins in humans?
Creppy EE, Moukha S, Bacha H, Carratu MR.
Dept of Toxicology, University of Bordeaux 2, 146, rue Lóo-Saignat, 33076 Bordeaux, France. email@example.com
Despite consented efforts in prevention, mycotoxins remain a problem of human health concern in several parts of the world including developed countries. Within the same range of toxins concentrations in the blood some people develop a disease while others do not. Could this inequality in front of mycotoxins effects be explained by environment factors and/or genetic predisposition? Among recent advances in environmental health research Correlation between chronic diseases and mycotoxins in humans deserves attention through several questions: Are genetic factors involved in disease causation of mycotoxins? How much are these factors currently taken into account for mycotoxins risk assessment and how much should we involve them? Answers are still to come. Genetic and environment factors deserve therefore more attention when dealing with regulatory limits, since among the general population, those who are at risk and will develop specific diseases are likely those bearing genetic predispositions. We have addressed these questions for the specific case of ochratoxin A in humans by investigating in Tunisia, county of Jelma, in four rural families forming a household of 21 persons all exposed to ochratoxin A in diet. Our results confirm that ochratoxin A induces chronic tubular nephropathy in humans and mainly point at those having the HLA haplotype A3, B27/35, DR7 to be more sensitive to the disease for quantitatively similar or lower exposure. Persons with such haplotype were found to bear chronic interstitial nephropathy with tubular karyomegalic cells while others were apparently healthy. Godin et al. (1996) in France have also found in sibling (a sister and her brother from urban area) that have similar HLA haplotype B35-patern, OTA-related renal tubulopathy with mild proteinuria including beta2-microglobulinuria. Several mechanisms are discussed that could be put ahead to explain how the HLA haplotype could lead to tubular cells lyses and renal failure. In the mean time it is urgent to search for mass screening biomarkers for mycotoxins in humans and related genetic factors to set-up more appropriate regulation.
PMID: 16705817 [PubMed - indexed for MEDLINE]
48. Int J Food Microbiol. 2006 Sep 1;111 Suppl 1:S61-6. Epub 2006 May 15.
Aspergillus spp., distribution, population composition and ochratoxin A production in wine producing vineyards in Greece.
Tjamos SE, Antoniou PP, Tjamos EC.
Agricultural University of Athens, Department of Plant Pathology, 75 Iera Odos str, Votanikos 11855, Athens, Greece.
Vineyard surveys of 11 wine producing grape cultivars, were carried out in sixteen vineyards, in five winemaking regions in Greece, during 2002 and 2003. The occurrence of various Aspergillus spp. in bunches of berries at setting, veraison and ripening at harvest time was investigated. Aspergillus niger aggregate and A. carbonarius were predominantly isolated from sampled berries. Although the prevailing Aspergillus spp. isolates belonged to A. niger aggregate, isolates of A. carbonarius were the most efficient ochratoxin A (OTA) producers. Of 50 tested isolates of A. carbonarius 42% produced amounts of OTA, exceeding 25 ppb, while none of the 85 isolates of A. niger aggregate tested produced above 16 ppb.
PMID: 16701912 [PubMed - indexed for MEDLINE]
49. Life Sci. 2006 Aug 22;79(13):1242-7. Epub 2006 Apr 3.
Expression of COX-2 and hsp72 in peritoneal macrophages after an acute ochratoxin A treatment in mice.
Ferrante MC, Bilancione M, Raso GM, Esposito E, Iacono A, Zaccaroni A, Meli R.
Department of Pathology and Animal Health, University of Naples Federico II, Naples, Italy.
Ochratoxin A (OTA) is a secondary fungal metabolite produced by Aspergillus and Penicillium strains that elicits a broad spectrum of toxicological effects in animals and man. A single oral OTA administration (10 mg/kg) in mice induced after 24 h oxidative damage and polymorphonuclear leukocyte (PMN) infiltration in parenchymal organs. In fact, OTA treatment increased lipid peroxidation (via malondialdehyde formation) in kidney and liver and PMN accumulation in duodenum, as shown by myeloperoxidase activity. Following in vivo OTA treatment an increase of cyclooxygenase-2 and of heat shock protein 72 expression was evidenced in peritoneal macrophage lysates by Western blot. That OTA modulates these proteins involved in the inflammatory process indicates that the mycotoxin is able to activate immune cells. This study suggests that the oxidative stress, the neutrophil accumulation in parenchymal tissues and the modulation of inflammatory parameters in peritoneal macrophages induced by OTA are involved in its toxicity, and represent early events related to several aspects of OTA mycotoxicosis.
PMID: 16643956 [PubMed - indexed for MEDLINE]
50. Mol Med. 2005 Jan-Dec;11(1-12):30-8.
Ochratoxin A-induced renal cortex fibrosis and epithelial-to-mesenchymal transition: molecular mechanisms of ochratoxin A-injury and potential effects of red wine.
Gagliano N, Torri C, Donetti E, Grizzi F, Costa F, Bertelli AA, Migliori M, Filippi C, Bedoni M, Panichi V, Giovannini L, Gioia M.
Department of Human Morphology, University of Milan, Italy. firstname.lastname@example.org
We characterized the effect of chronic ochratoxin A (OTA) on rat kidney cortex, analyzing collagen content and collagen turnover and the major markers of epithelial-to-mesenchymal transition (EMT), such as alpha-smooth muscle actin (alphaSMA), cadherins, and MMP-9. Because OTA nephrotoxicity is mediated by free radicals, we also investigated whether antioxidants in red wine provided protection for the kidney and attenuated OTA-induced EMT. Collagen content, determined by computerized analysis of Sirius red-stained kidney sections, increased in OTA, OTA-wine, and OTA-EtOH treated rats. In kidney cortex homogenates, COL-I and COL-III mRNA levels tended to rise in OTA treated rats, but were similar to CT after OTA-wine and OTA-EtOH administration. TIMP-1 gene expression was up-regulated in OTA, OTA-wine, and OTA-EtOH treated rats. LH2b mRNA/COL-I mRNA was significantly up-regulated in OTA-wine and OTA-EtOH treated rats, compared with CT and OTA alone. TGF-beta1 signaling tended to dominate after OTA, OTA-wine, and OTA-EtOH. MMP-1 protein levels were not affected. OTA induced proMMP-9 and alphaSMA overexpression, decreases of E-cadherin and N-cadherin, and DSC-2 up-regulation. OTA-wine caused a further, unexpected decrease of E- and N-cadherins and further up-regulation of OTA-induced DSC-2, while strongly reducing the OTA-induced increases of alphaSMA and proMMP-9. Posttranslational collagen modifications, such as decreased collagen degradation through MMP inhibition and increased collagen cross-links, seem to be key mechanisms leading to OTA-induced kidney cortex fibrosis. This mechanism was not affected by red wine in these conditions. Red wine seems to have some protective role against OTA-induced EMT, although without completely blocking the process and determining a condition in which abundant cells display an intermediate translational phenotype, but there are no alphaSMA or epithelial markers.
PMCID: PMC1449520 PMID: 16622519 [PubMed - indexed for MEDLINE]
51. BMC Complement Altern Med. 2006 Mar 14;6:6.
Effect of dietary honey on intestinal microflora and toxicity of mycotoxins in mice.
Ezz El-Arab AM, Girgis SM, Hegazy EM, Abd El-Khalek AB.
Department of Food Science and Nutrition, National Research Center, 12644 - Dokki, Giza, Egypt. email@example.com
BACKGROUND: Bee honey is a functional food which has a unique composition, antimicrobial properties and bifidogenic effect. In order to assess whether honey can inhibit the toxic effect of mycotoxins, the present study was undertaken. METHODS: Production of biomass and toxins by Aspergillus parasiticus and Aspergillus ochraceus were followed in media without and with honey. Although aflatoxins and ochratoxin A. were administrated to male Swiss albino mice up to 1 mug and 10 ng/kg body weight/day respectively. The experimental animals were fed diets without our with 10% honey for two months. The changes in colonic probiotic bacteria, determintal colon enzyme glucuronidases, and genotoxicity were followed. RESULTS: Addition of 32% in its media increased the biomass of A parasiticus, while the biomass of A. ochraceus decreased and Ochratoxin A. was not produced. When the honey was added at the ratio of 32 and 48% in the medium. No relationship was found between mycelium weight and production of mycotoxins. Oral administration of aflatoxins (mixture of B1, B2, G1 and G2) and Ochratoxin A. induced structural and numerical chromosomal aberrations in bone marrow and germ cells of male mice, whereas, honey treatment reduced the genotoxicity of mycotoxins. Also both toxins induced histopathological changes in liver and kidney. Feeding on diet supplemented with honey improved the histopathological changes in case of aflatoxin group, but not in the case of ochratoxin A. group (except of kidney in two cases). No significant differences were found in the activity of colon beta-glucuronidase between group fed diet with or without honey. On the other hand, the colon bifido bacteria and lactobacilli counts were increased markedly in group receiving diet supplemented with honey. CONCLUSION: Substituting sugars with honey in processed food can inhibit the harmful and genotoxic effects of mycotoxins, and improve the gut microflora.
PMCID: PMC1431562 PMID: 16533410 [PubMed - indexed for MEDLINE]
52. Food Addit Contam. 2005;22 Suppl 1:58-64.
Renal tumourigenesis in male rats in response to chronic dietary ochratoxin A.
Mantle P, Kulinskaya E, Nestler S.
Department of Environmental Science and Technology, Imperial College London, UK. firstname.lastname@example.org
The potency of ochratoxin A (OTA) as a renal carcinogen in the rat in response to lifetime administration by oral gavage is a basis of current concern about possible human risk from dietary exposure to the mycotoxin. In this study, dietary delivery of OTA was chosen as the mode of administration, since this mimics human intake of OTA-contaminated food more accurately than gastric intubation. Young male Fischer rats were given approximately 300 microg OTA/kg body weight (bwt) daily until they reached 333 g; thereafter their daily intake was held at about 100 microg. Renal tumours, mostly unilateral carcinomas, were first discovered at week 75 and total incidence reached 25%. Statistical comparison of total carcinoma incidence (20%) in this study with that of the classic US NTP study suggested that OTA was significantly less carcinogenic when administered in feed than when given by oral gavage. The finding may moderate perceptions of a putative risk of trace amounts of OTA in some foodstuffs to human health.
PMID: 16332623 [PubMed - indexed for MEDLINE]
53. Toxicol Sci. 2006 Jan;89(1):120-34. Epub 2005 Oct 26.
A toxicogenomics approach to identify new plausible epigenetic mechanisms of ochratoxin a carcinogenicity in rat.
Marin-Kuan M, Nestler S, Verguet C, Bezençon C, Piguet D, Mansourian R, Holzwarth J, Grigorov M, Delatour T, Mantle P, Cavin C, Schilter B.
Nestlé Research Center, PO Box 44, Vers-chez-les-Blanc, CH-1000 Lausanne 26, Switzerland. email@example.com
Ochratoxin A (OTA) is a mycotoxin occurring naturally in a wide range of food commodities. In animals, it has been shown to cause a variety of adverse effects, nephrocarcinogenicity being the most prominent. Because of its high toxic potency and the continuous exposure of the human population, OTA has raised public health concerns. There is significant debate on how to use the rat carcinogenicity data to assess the potential risk to humans. In this context, the question of the mechanism of action of OTA appears of key importance and was studied through the application of a toxicogenomics approach. Male Fischer rats were fed OTA for up to 2 years. Renal tumors were discovered during the last 6 months of the study. The total tumor incidence reached 25% at the end of the study. Gene expression profile was analyzed in groups of animals taken in intervals from 7 days to 12 months. Tissue-specific responses were observed in kidney versus liver. For selected genes, microarray data were confirmed at both mRNA and protein levels. In kidney, several genes known as markers of kidney injury and cell regeneration were significantly modulated by OTA. The expression of genes known to be involved in DNA synthesis and repair, or genes induced as a result of DNA damage, was only marginally modulated. Very little or no effect was found amongst genes associated with apoptosis. Alterations of gene expression indicating effects on calcium homeostasis and a disruption of pathways regulated by the transcription factors hepatocyte nuclear factor 4 alpha (HNF4alpha) and nuclear factor-erythroid 2-related factor 2 (Nrf2) were observed in the kidney but not in the liver. Previous data have suggested that a reduction in HNF4alpha may be associated with nephrocarcinogenicity. Many Nrf2-regulated genes are involved in chemical detoxication and antioxidant defense. The depletion of these genes is likely to impair the defense potential of the cells, resulting in chronic elevation of oxidative stress in the kidney. The inhibition of defense mechanism appears as a highly plausible new mechanism, which could contribute to OTA carcinogenicity.
PMID: 16251485 [PubMed - indexed for MEDLINE]
54. J Agric Food Chem. 2005 Aug 24;53(17):6924-9.
Effect of ethanol and red wine on ochratoxin a-induced experimental acute nephrotoxicity.
Bertelli AA, Migliori M, Filippi C, Gagliano N, Donetti E, Panichi V, Scalori V, Colombo R, Mannari C, Tillement JP, Giovannini L.
University of Milan, Milan, Italy.
Ochratoxin A (OTA), is a nephrotoxic mycotoxin present in wine, which is nephrotoxic in humans. Our working hypothesis is that natural substances in wine may counteract OTA toxicity. Thirty-six rats were randomized to OTA dissolved in saline, red wine, or 13.5% ethanol or to OTA-free wine, ethanol, or saline. OTA (289 microg/kg of body weight/48 h) was administered by gastric gavage for 2 weeks. Serum creatinine, tubular enzymuria, renal lipohydroperoxides (LOOH), reduced (GSH) and oxidized (GSSG) glutathione, and renal superoxide dismutase activity (SOD) were determined in renal tissue. OTA alone produced significant increases in renal lipoperoxides and significant decreases in SOD and GSH/GSSG ratio. In red wine or ethanol, OTA was less nephrotoxic, reducing oxidative damage as revealed by LOOH. In OTA-wine and OTA-ethanol groups, SOD activity was higher than in the OTA-treated one, suggesting that both ethanol and nonalcoholic fractions may preserve antioxidant reserve. GSH/GSSG ratio was significantly preserved only in the OTA-wine group and not in OTA-ethanol. Red wine may exert a protective effect against OTA nephrotoxicity by limiting oxidative damage. The ostensible protection afforded by ethanol deserves further investigation.
PMID: 16104822 [PubMed - indexed for MEDLINE]
55. Chem Res Toxicol. 2005 Aug;18(8):1242-52.
Functional, biochemical, and pathological effects of repeated oral administration of ochratoxin A to rats.
Mally A, Völkel W, Amberg A, Kurz M, Wanek P, Eder E, Hard G, Dekant W.
Department of Toxicology, University of Würzburg, Germany.
Ochratoxin A (OTA), a mycotoxin produced by several fungi of Aspergillus and Penicillium species, may contaminate agricultural products, resulting in chronic human exposure. In rats, OTA is a potent nephrotoxin, and repeated administration of OTA for 2 years to rats in doses up to 0.21 mg/kg of body wt resulted in high incidences of renal tumors arising from the proximal tubular epithelial cells. The mechanism of tumor formation by OTA in the kidney is not well-defined, and controversial results regarding mode of action have been published. The aim of this study was to characterize dose-dependent changes induced by OTA by application of clinical chemistry, biochemical markers, and toxicokinetics for a better conclusion on modes of action. Administration of OTA (0, 0.25, 0.5, 1, and 2 mg/kg of body wt) to male F344 rats (n = 3 per group) by oral gavage for 2 weeks resulted in a dose-dependent increase in OTA plasma concentrations and concentrations of OTA in both liver and kidney. Although oxidative stress has been implicated in OTA carcinogenicity, treatment with OTA did not induce overt lipid peroxidation or an increase in 8-oxo-7,8-dihydro-2'deoxyguanosine (8-OH-dG) in kidney. In the kidney, OTA-induced pathology was present at all dose levels administered, with a clear increase in severity related to dose. Pathology was restricted to the outer stripe of the outer medulla and consisted of disorganization of the tubule arrangement, frequent apoptotic cells, and abnormally enlarged nuclei scattered through the S3 tubules. Consistent with the histopathology, a dose-dependent increase in the expression of proliferating cell nuclear antigen (PCNA), indicative of cell proliferation, was observed in kidneys, but not in livers of treated animals. The most prominent change in the composition of urine induced by OTA analyzed by 1H NMR and principal component analysis consisted of a major increase in the excretion of trimethylamine N-oxide. However, typical changes observed with other proximal tubular toxins such as increased excretion of glucose were not observed at any of the doses administered. Similarly, treatment with OTA had no clear effects on clinical chemical parameters indicative of nephrotoxicity, although urinary volume was increased at the higher-dose groups. Taken together, the uncommon changes induced by OTA suggest that a unique mechanism may be involved in OTA nephrotoxicity and carcinogenicity.
PMID: 16097797 [PubMed - indexed for MEDLINE]
56. Toxicology. 2005 Nov 5;215(1-2):37-47. Epub 2005 Jul 28.
Teratogenic effects in rabbits of simultaneous exposure to ochratoxin A and aflatoxin B1 with special reference to microscopic effects.
Wangikar PB, Dwivedi P, Sinha N, Sharma AK, Telang AG.
Division of Pathology, Indian Veterinary Research Institute, Izatnagar 243122, Bareilly, UP, India. firstname.lastname@example.org
To elucidate the teratogenic effects, ochratoxin A (OTA) and aflatoxin B1 (AFB1) were dissolved in corn oil and administered in combination to New Zealand White rabbits during 6-18 days of gestation orally with the dose levels of OTA+AFB1, 0.05+0.05 and 0.1+0.1mg/kg body weight. To assess pathomorphological features of the anomalies, the fetal serial sections were histologically examined. There was no mortality in any of the treated groups. Body weights and body weight gains of dams in the combined treatment groups were comparable with those of controls and individual treatments. The mean crown to rump lengths in both the combination dose groups and mean fetal weights in high dose combination group were significantly decreased. In the high dose combination, there was increase in the percent of implants resorbed and significant increase in the incidence of visceral anomalies. The combination treatment resulted in various gross, skeletal and visceral anomalies such as wrist drop, scoliosis, bent metacarpals, rudimentary ribs, cardiac defects and microphthalmia. There was a dose-related increase in the percent of litters showing the histopathological changes in the fetal tissues. The incidence of histopathological changes in the tissue sections prepared from fetal liver, kidneys, brain, heart and eyes was found increased in the high dose combination group. The comparative evaluation of the results of combination versus individual treatments revealed that certain anomalies observed in the individual treatment of OTA such as knuckling of fetlock, rudimentary tail or agenesis of tail, wavy ribs, hydrocephalus and agenesis of kidney and AFB1 as enlarged eye sockets and enlarged liver were absent in the combination treatment. However, some new manifestations such as cardiac defects and scoliosis were seen. The results of the present study indicated that in combination, OTA and AFB1 have antagonistic interaction. The presence of subtle lesions histologically due to an interference with normal development suggested that microscopic examination of the fetal tissues could provide additional, useful information to a developmental toxicity study.
PMID: 16054743 [PubMed - indexed for MEDLINE]
57. Toxicol Appl Pharmacol. 2005 Aug 1;206(1):43-53. Epub 2005 Jan 7.
Biotransformation and nephrotoxicity of ochratoxin B in rats.
Mally A, Keim-Heusler H, Amberg A, Kurz M, Zepnik H, Mantle P, Völkel W, Hard GC, Dekant W.
Institut für Toxikologie, Universität Würzburg, 97078 Würzburg, Germany.
Ochratoxin B (OTB), a secondary metabolite of Aspergillus ochraceus, is the nonchlorinated analogue of the mycotoxin ochratoxin A (OTA), which is one of the most potent renal carcinogens in rodents. Despite the closely related structure, OTB is considered to be of much lower toxicity. OTA is poorly metabolized and slowly eliminated, and this may play an important role in OTA toxicity, carcinogenicity, and organ specificity. Since little is known regarding biotransformation and renal toxicity of OTB, the aim of this study was to investigate biotransformation of OTB in rats and to characterize the nephrotoxicity and cytotoxicity of OTB. Male F344 rats were administered either a single dose of OTB (10 mg/kg bw) or repeated doses (2 mg/kg bw, 5 days/week for 2 weeks) and euthanized 72 h after the last dosing. In proximal tubule cells of animals treated with a single high dose of OTB, a slight increase in mitotic figures was observed, but no treatment-related changes were evident in clinical chemistry, in renal function, and histopathology after repeated administration. Excretion of OTB and metabolites in urine and feces was analyzed using both HPLC with fluorescence detection and LC-MS/MS. Ochratoxin beta, which results from cleavage of the peptide bond, was the major metabolite excreted in urine in addition to small amounts of 4-hydroxy-OTB. In total, 19% of the administered dose was recovered as OTB and ochratoxin beta in urine and feces within 72 h after a single dose. In contrast to OTA, no tissue-specific retention of OTB was evident after single and repeated administration. In LLC-PK1 cells, a renal cell culture system that retains much of the specific features of the proximal tubule, only minor differences in the extent of cytotoxicity of OTA and OTB were observed. At low concentrations (< 25 microM), treatment with OTA was slightly more toxic, whereas reduction in cell viability was similar at concentrations up to 100 microM. In summary, these data suggest that OTA and OTB have a similar potential to induce cytotoxicity in vitro, but large differences in their potential to induce nephrotoxicity in rodents. OTB is more extensively metabolized and more rapidly eliminated than OTA. The lack of specific retention of OTB in the kidneys and the differences in toxicokinetics may therefore provide an explanation for the lower toxicity of OTB.
PMID: 15963343 [PubMed - indexed for MEDLINE]
58. Toxicol Lett. 2005 Apr 10;156(2):315; author reply 317. Epub 2005 Jan 18.
Re: Comments on paper by Son et al.
Castegnaro M, Pfohl-Leszkowicz A, Bartsch H, Tillmann T, Mohr U.
Comment on Toxicol Lett. 2003 Apr 30;142(1-2):19-27.
PMID: 15737494 [PubMed - indexed for MEDLINE]
59. Mol Nutr Food Res. 2005 Feb;49(2):118-30.
Ochratoxin A at nanomolar concentrations: a signal modulator in renal cells.
Gekle M, Sauvant C, Schwerdt G.
Physiologisches Institut der Universität Würzburg, Würzburg, Germany. email@example.com
Ochratoxin A (OTA) is a ubiquitous fungal metabolite with nephrotoxic, carcinogenic, and apoptotic potential. Toxicokinetics make the kidney the primary target organ for OTA. Due to its widespread occurrence in improperly stored foodstuff the complete and safe avoidance of OTA for humans is impossible. There are several reports showing a significant correlation between OTA exposure and certain forms of nephropathies. At nanomolar concentrations OTA leads to specific changes of function and phenotype in renal cells. The toxin interacts with certain cellular "key-molecules" (e. g., mitogen-activated protein (MAP) kinases, Ca2+), thereby disturbing cellular signalling and regulation events as well as mitochondrial function. Moreover, OTA has the ability to modulate physiological signals (e. g., angiotensin II or TNFalpha) and thereby influences cell function and cell growth and may even stable re-program the cells (e. g., altered distribution of chromosomes). This review concentrates on the effects of OTA in the nanomolar range and its interactions with cellular signalling networks in different renal cells proposing OTA to act as a signal modulator.
PMID: 15635689 [PubMed - indexed for MEDLINE]
60. J Pharmacol Exp Ther. 2005 Apr;313(1):234-41. Epub 2004 Dec 30.
Proximal tubular toxicity of ochratoxin A is amplified by simultaneous inhibition of the extracellular signal-regulated kinases 1/2.
Sauvant C, Holzinger H, Gekle M.
Physiologisches Institut der Universitüt Würzburg, Röntgenring 9, 97070 Würzburg, Germany. firstname.lastname@example.org
Ochratoxin A (OTA) is a mycotoxin involved in the development of chronic nephropathies and a known carcinogen. As we have shown previously, OTA activates mitogen-activated protein kinases [extracellular signal-regulated kinase 1 and 2 (ERK1/2), c-jun amino-terminal kinase (JNK), and extracellular-regulated protein kinase 38 (p38)] in proximal tubular cells (opossum kidney and normal rat kidney epithelial). ERK1/2, JNK, or p38 are thought to mediate opposite action on apoptosis, fibrosis, and inflammation. As we have already shown, OTA activates the latter processes. Here, we investigated the effect of OTA in the absence or presence of the ERK1/2 inhibitor U0126 [1,4-diamino-2,3-dicyano-1,4bis(2-aminophenylthio)-butadiene] to test whether OTA then will exert increased toxicity. In the presence of ERK1/2 inhibition, OTA decreased cell number and protein to a significantly larger extent compared with OTA alone. The same was true for epithelial tightness, apoptosis (caspase-3 activity), and necrosis (lactate dehydrogenase release). Furthermore, simultaneous inhibition of ERK1/2 amplified the effect of OTA on markers of inflammation (nuclear factor of the kappa-enhancer in B cells activity), fibrosis (collagen secretion), and epithelial mesenchymal transition (alpha smooth muscle actin). OTA induces phenomena typical for chronic interstitial nephropathy and activates ERK1/2, JNK, and p38 in proximal tubular cells. Inhibition of ERK1/2 aggravates the effects of OTA or even induces toxicity at normally nontoxic concentrations. This is highly likely due to activation of JNK and p38. Our data indicate a new mechanistic explanation for the toxic actions induced by OTA, and they are notable with respect to a possible coexposition of the kidney to OTA and naturally occurring ERK1/2 inhibitors. Finally, our data give rise to an attractive hypothesis on the coincidence of increased OTA exposition and urinary tract tumors in humans.
PMID: 15626719 [PubMed - indexed for MEDLINE]
61. Birth Defects Res B Dev Reprod Toxicol. 2004 Dec;71(6):352-8.
Effect in rats of simultaneous prenatal exposure to ochratoxin A and aflatoxin B1. II. Histopathological features of teratological anomalies induced in fetuses.
Wangikar PB, Dwivedi P, Sharma AK, Sinha N.
Divison of Pathology, Indian Veterinary Research Institute, Izatnagar, Bareilly, India. email@example.com
The histopathological features of various abnormalities induced by different doses of ochratoxin A (OA), aflatoxin B1 (AFB1), and their combination in rat fetuses were studied. The pregnant Wistar rats were orally treated during 6-15 gestation days with different doses of OA (0.125, 0.25, 0.50, 0.75 mg/kg), AFB1 (0.125, 0.25, 0.50, 1.00 mg/kg), and their combination (0.125+0.125, 0.25+0.50, 0.50+0.25 mg/kg). The fetal sections passing through liver, kidney, brain, heart, and eyes were selected from the fetuses given visceral examination representing each litter. The selected sections were processed for paraffin embedding, stained with H and E, and examined by light microscopy. The histological examination of the fetal organs revealed that OA, AFB1, and their combination treatments caused variable changes in internal organs. In the case of OA, the incidence of pathological lesions liver, kidney, brain, and eye lesions was high, whereas in AFB1 treatment, liver, brain, kidney, and heart were affected. The incidence of heart lesions, especially valvular defects, increased in the combination groups. Bile duct proliferation/new bile duct formation, defective ossification of cranial bones, exposure of the brain to the exterior, hypoplasia of cerebellum, and retinal defects observed in OA treatment and spinal cord defects in addition to liver, kidney, and brain changes observed in AFB1 were less severe in the combination groups. The present study indicates that the occurrence of brain, kidney, and liver lesions in combination treatment was less than in either individual treatment suggesting antagonism of OA-induced teratogenic effects by AFB1. The indication of subtle lesions due to an interference with normal development and arrest of differentiation in various internal organs observed in the present study suggests that microscopic examination of the tissues can provide additional useful information to a developmental toxicity study.
Copyright 2004 Wiley-Liss, Inc.
PMID: 15617025 [PubMed - indexed for MEDLINE]
62. Birth Defects Res B Dev Reprod Toxicol. 2004 Dec;71(6):343-51.
Effect in rats of simultaneous prenatal exposure to ochratoxin A and aflatoxin B1. I. Maternal toxicity and fetal malformations.
Wangikar PB, Dwivedi P, Sinha N.
Division of Pathology, Indian Veterinary Research Institute, Izatnagar, India. firstname.lastname@example.org
Ochratoxin A (OA) and Aflatoxin B1 (AFB1), the food borne mycotoxins are produced by several fungal species of the genera Aspergillus and Penicillium. To determine the teratogenic effects, these mycotoxins were administered orally either individually or in combination to the pregnant Wistar rats on days 6-15 of gestation. OA and AFB1 were dissolved in corn oil and different doses of OA (0.125, 0.25, 0.50, and 0.75 mg/kg), AFB1 (0.125, 0.25, 0.50, and 1.00 mg/kg), and a combination of OA+AFB1 (0.125+0.125; 0.25+0.50; 0.50+0.25 mg/kg) were given by gastric intubation to rats. During dosing period, the body weight and body weight gains significantly decreased at a higher dosage, in both individual and combined treatments. In all the combination treatments, the percent implants resorbed, fetal body weights, and crown-rump lengths were comparable to those of controls and with the individual mycotoxin treatment. The number of dead fetuses was significantly increased in the high OA combination (OA+AFB1 0.50+0.25) group as compared with the other two combinations. OA and AFB1 alone and in combination caused various gross, skeletal, and visceral anomalies. The occurrence was considerably less pronounced in fetuses of AFB1 and combination groups as compared with those of OA group fetuses. The exencephaly, incomplete closure of skull, wavy and fused ribs, agenesis of the ischium bone, and enlarged renal pelvis, recorded in OA treatment and ear abnormality and incomplete ossification of skull bones observed in AFB1 when given individually, were not seen in combination groups. However, new manifestations, such as gastroschisis and syndactyly were observed and the incidence of cardiac defects was increased in fetuses due to the combined treatment. The results of the present study indicated that there is some interaction between these mycotoxins that resulted in reduced teratogenic activity of OA in the presence of AFB1. Apparently, new manifestations observed in combination treatment points to the potential threat of teratogenicity in terms of public health hazards.
Copyright 2004 Wiley-Liss, Inc.
PMID: 15617020 [PubMed - indexed for MEDLINE]
63. Arh Hig Rada Toksikol. 2004 Nov;55(4):243-8.
Ochratoxin A-induced apoptosis in rat kidney tissue.
Domijan AM, Peraica M, Ferencić Z, Cuzić S, Fuchs R, Lucić A, Radić B.
Unit of Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia.
The aim of our study was to find whether ochratoxin A (OTA) induces the apoptosis and/or necrosis of kidney tissue in rats. In the first experiment, the highest number of apoptotic cells was found in rats sacrificed one day after OTA administration (1.00 mg/kg b.w., i.p.). The number of apoptotic cells reduced gradually and they were not seen nine days after OTA administration. A possible dose-dependence of histological changes was checked in kidney tissue of rats given 0.25, 0.50 or 1.00 mg of OTA/kg b.w., i.p. three times a week for four weeks. The number of apoptotic cells showed a clear dose-dependence, but necrosis was absent even at the highest doses. The time-dependent appearance of lesions related to OTA administration was checked by administering 0.50 mg OTA/kg body weight to rats, and sacrificing them one day after 1, 3, 6, and 9 doses/administrations, or 6 and 21 day after 12 doses/administrations. Long-term administration is associated with continued and increased apoptosis without necrosis, suggestive of OTA's role in the pathogenesis of progressive renal atrophy.
PMID: 15584550 [PubMed - indexed for MEDLINE]
64. Toxicol In Vitro. 2005 Feb;19(1):135-43.
A rapid screening method to test apoptotic synergisms of ochratoxin A with other nephrotoxic substances.
Weber F, Freudinger R, Schwerdt G, Gekle M.
Physiologisches Institut, Universität Würzburg, Röntgenring 9, D-97070 Würzburg, Germany.
The body may be exposed simultaneously to more than one nephrotoxic substance and to measure the effects of the great number of possible combinations of nephrotoxins will rapidly become a great challenge when using the traditional methods. Therefore, we developed a rapid and cost-efficient method to screen the apoptotic potential of combinations of known cell- or nephrotoxic substances as ochratoxin A (OTA), cisplatin, cadmium, H(2)O(2), and amphotericin B on renal epithelial cell lines. The cells were seeded in 96-well plates and the apoptotic and necrotic potential of different combinations of nephrotoxins was determined. We found different results for the combinations used: depending on the concentrations of the various substances, antagonistic, additive, or potentiating effects on caspase-3 activity were found after co-exposure to OTA. We conclude that the co-exposure of renal cells to OTA with other substances can enhance or reduce the apoptotic potential of one substance alone depending on the substance, the concentration and on the cell line investigated. A "harmless" substance can thus convert to a potent cell toxic substance when combined with OTA or vice versa. The underlying mechanisms of the synergistic effects remain unknown.
PMID: 15582364 [PubMed - indexed for MEDLINE]
65. J Appl Toxicol. 2004 Nov-Dec;24(6):505-12.
Protective role of melatonin in ochratoxin a toxicity in rat heart and lung.
Okutan H, Aydin G, Ozcelik N.
Süleyman Demirel University, School of Medicine, Department of Cardiovascular Surgery, Isparta, Turkey. email@example.com
Ochratoxin A (OTA) is a mycotoxin produced by different fungi. The most pronounced adverse effect of OTA is hepatonephrotoxicity. Melatonin (MEL) has an antioxidant effect and has free-radical scavenger properties. The effects of OTA on heart and lung tissue and possible ameliorating effects of MEL were investigated in rats. Twenty-four rats were allocated to three groups (each with eight rats): control; OTA-treated group (OTA dose 289 microg kg(-1) per day); and OTA + MEL-treated group (MEL dose 10 mg kg(-1) per day). After 30 days of treatment, the histopathological changes in the heart and lung of all groups were examined. Compared with the control rats, myocardial tissue of rats treated with OTA showed extensive cytoplasmic vacuole formation, necrosis of the myocytes, dissolution of the nucleus, clumped fibres, fibrillolysis, swollen myocardial fibres, small haemorrhagic areas and hyperaemic vessels (P <0.05). In addition, lungs of rats treated with OTA showed alveolar congestion, alveolar cell hyperplasia, prominent alveolar septal vessels, variable intensity loss of alveolar architecture, intraparenchymal inflammatory infiltration, intraparenchymal hyperaemic vessels, respiratory epithelial proliferation, perivascular and peribronchial inflammation, pneumonic infiltration, distorted appearance of lung parenchyma and emphysematous areas (P <0.05). In comparison with the OTA groups, the ameliorating effects of MEL in the lung damage parameters were on alveolar cell hyperplasia, prominent alveolar septal vessels, variable intensity loss of alveolar architecture, intraparenchymal inflammatory infiltration, perivascular inflammatory inflammation, distorted appearance of lung parenchyma and focal emphysematous areas in lung (P <0.05). Melatonin also significantly reduced myocardial damage in most of the parameters: extensive cytoplasmic vacuole formation, necrosis of the myocytes, clumped fibres, fibrillolysis, small haemorrhagic areas and hypaeremic vessels in heart (P <0.05). On the other hand, MEL did not lower the degree of damage in lung and heart to the level of the control rats, except for the parameters of the interstitial oedema and small haemorrhagic areas only in myocardial tissue. Histopathological findings showed that OTA induced damage in heart and lung and MEL treatment significantly reduced the degree of damage.
PMID: 15558833 [PubMed - indexed for MEDLINE]
66. Cell Biol Toxicol. 2004 Jul;20(4):213-9.
The effects of ochratoxin A on lipid peroxidation and antioxidant enzymes: a protective role of melatonin.
Soyöz M, Ozçelik N, Kilinç I, Altuntaş I.
Department of Medical Biology and Genetics, Suleyman Demirel University, Faculty of Medicine, Isparta, Turkey. firstname.lastname@example.org
Various studies indicate that the mycotoxin ochratoxin A (OTA) is a carcinogenic, genotoxic, teratogenic, immunotoxic, and nephrotoxic agent. In the present study, the activities of some enzymes in the serum and liver of rats with ochratoxicosis and the effects of melatonin on these enzymes were investigated. Rats were divided into three equal groups, each consisting of eight rats; control, OTA (289 microg/kg per day) and OTA + melatonin groups for this study. In the OTA treated group, the level of lipid peroxidation (LPO) and the activities of glutathione peroxidase (GSH-Px) were increased in the liver and serum in comparison with the control group. The activities of catalase (CAT) and superoxide dismutase (SOD) were significantly changed in the serum when compared with controls. Our results showed structural tissue damage in the liver in OTA-treated rats. Melatonin decreased the OTA-induced damage to support the antioxidant defense system and/or with free radical scavenger action.
PMID: 15499969 [PubMed - indexed for MEDLINE]
67. Vet Res Commun. 2004 Aug;28 Suppl 1:371-5.
Swine ochratoxicosis: proteomic investigation of epatic bioindicators.
Roncada P, Carta F, Zannotti M, Malagutti L, Sciaraffia F, Greppi GF.
Lab. Epigenomica Applicata ISILS Milano , Italy. email@example.com
PMID: 15373000 [PubMed - indexed for MEDLINE]
68. Hum Exp Toxicol. 2004 Jul;23(7):339-46.
Karyomegaly of tubular kidney cells in human chronic interstitial nephropathy in Tunisia: respective role of Ochratoxin A and possible genetic predisposition.
Hassen W, Abid-Essafi S, Achour A, Guezzah N, Zakhama A, Ellouz F, Creppy EE, Bacha H.
Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Rue Avicenne, Monastir, Tunisia.
Karyomegalic nephropathy associated to bizarre enlargement of nuclei in renal tubular epithelial cells was first described by Mihatch in 1979. We present herein additional cases occurring in three siblings suffering from chronic interstitial nephropathy (CIN) of unknown aetiology where the renal biopsies showed numerous enlarged and hyperchromatic nuclei. CIN of unknown aetiology has been previously characterized and showed striking similarities with Balkan Endemic Nephropathy (BEN). Ochratoxin A (OTA) is a nephrotoxic mycotoxin suspected to be the causal agent of the BEN as well as the Tunisian CIN of unknown aetiology. OTA is incriminated in the onset of these disclosed cases of karyomegalic nephropathy since high OTA concentrations were found in blood (505.83 ng/ml, 102.63 ng/ml and 1023 ng/ml) and in urine (94.40 ng/ml and 10.18 ng/ml) of two of them. Moreover, we have investigated OTA in blood and urine as well as in food samples of the entire household (21 people). Our findings suggest (i) a link between OTA and the outcome of this karyomegalic nephropathy, and (ii) the possible involvement of a genetic factor since the three cases have the same haplotype B27/35.
PMID: 15311851 [PubMed - indexed for MEDLINE]
69. J Appl Toxicol. 2004 Jul-Aug;24(4):289-96.
Effects of rosmarinic acid against aflatoxin B1 and ochratoxin-A-induced cell damage in a human hepatoma cell line (Hep G2).
Renzulli C, Galvano F, Pierdomenico L, Speroni E, Guerra MC.
Department of Pharmacology, University of Bologna, via Irnerio 48, 40126 Bologna, Italy.
Recent findings have suggested that oxidative damage might contribute to the cytotoxicity and carcinogenicity of aflatoxin B(1) (AFB(1)). The induction of oxidative stress also plays an important role in the toxicity of another mycotoxin: ochratoxin A (OTA). In this study, the protective effect of rosmarinic acid (Ros A) against AFB(1) and OTA-induced cytotoxicity was investigated in a human hepatoma-derived cell line (Hep G2). Rosmarinic acid, a natural phenolic compound contained in many Lamiaceae herbs such as Perilla frutescens, sage, basil and mint, inhibits complement-dependent inflammatory processes and may have therapeutic potential. The ability of Ros A to reduce radical oxygen species (ROS) production, protein and DNA synthesis inhibition and apoptosis caused by the two mycotoxins was also investigated. Our experiments proved the significant cytoprotective effect of Ros A in vitro from OTA- and AFB(1)-induced cell damage. In particular, 24-h pretreatment with 50 micro M Ros A inhibited the cytotoxicity of 10 micro M AFB(1) (by 45%) and 10 micro M OTA (by 35%) in Hep G2 cells (P < 0.001). Moreover, Ros A dose dependently attenuated ROS production and DNA and protein synthesis inhibition induced by both of the toxins. Similarly, apoptosis cell death was prevented, as demonstrated by reduction of DNA fragmentation and inhibition of caspase-3 activation (P < 0.001).
Copyright 2004 John Wiley & Sons, Ltd.
PMID: 15300717 [PubMed - indexed for MEDLINE]
70. Crit Rev Toxicol. 2004 May-Jun;34(3):211-99.
Chemically induced renal tubule tumors in the laboratory rat and mouse: review of the NCI/NTP database and categorization of renal carcinogens based on mechanistic information.
Lock EA, Hard GC.
Syngenta Central Toxicology Laboratory, Macclesfield, Cheshire, United Kingdom. firstname.lastname@example.org
The incidence of renal tubule carcinogenesis in male and female rats or mice with 69 chemicals from the 513 bioassays conducted to date by the NCI/NTP has been collated, the chemicals categorized, and the relationship between carcinogenesis and renal tubule hyperplasia and exacerbation of the spontaneous, age-related rodent disease chronic progressive nephropathy (CPN) examined. Where information on mechanism or mode of action exists, the chemicals have been categorized based on their ability to directly or indirectly interact with renal DNA, or on their activity via epigenetic pathways involving either direct or indirect cytotoxicity with regenerative hyperplasia, or exacerbation of CPN. Nine chemicals were identified as directly interacting with DNA, with six of these producing renal tubule tumors at high incidence in rats of both sexes, and in some cases also in mice. Ochratoxin A was the most potent compound in this group, producing a high tumor incidence at very low doses, often with metastasis. Three chemicals were discussed in the context of indirect DNA damage mediated by an oxidative free radical mechanism, one of these being from the NTP database. A third category included four chemicals that had the potential to cause DNA damage following conjugation with glutathione and subsequent enzymatic activation to a reactive species, usually a thiol-containing entity. Two chemicals were allocated into the category involving a direct cytotoxic action on the renal tubule followed by sustained compensatory cell proliferation, while nine were included in a group where the cell loss and sustained increase in renal tubule cell turnover were dependent on lysosomal accumulation of the male rat-specific protein, alpha2mu-globulin. In a sixth category, morphologic evidence on two chemicals indicated that the renal tumors were a consequence of exacerbated CPN. For the remaining chemicals, there were no pertinent data enabling assignment to a mechanistic category. Accordingly, these chemicals, acting through an as yet unknown mechanism, were grouped as either being associated with an enhancement of CPN (category 7, 16 chemicals), or not associated with enhanced CPN (category 8, 4 chemicals). A ninth category dealt with 11 chemicals that were regarded as producing increases in renal tubule tumors that did not reach statistical significance. A 10th category discussed 6 chemicals that induced renal tumors in mice but not in rats, plus 8 chemicals that produced a low incidence of renal tubule tumors in mice that did not reach statistical significance. As more mechanistic data are generated, some chemicals will inevitably be placed in different groups, particularly those from categories 7 and 8. A large number of chemicals in the series exacerbated CPN, but those in category 7 especially may be candidates for inclusion in category 6 when further information is gleaned from the relevant NTP studies. Also, new data on specific chemicals will probably expand category 5 as cytotoxicity and cell regeneration are identified as obligatory steps in renal carcinogenesis in more cases. Additional confirmatory outcomes arising from this review are that metastases from renal tubule tumors, while encountered with chemicals causing DNA damage, are rare with those acting through an epigenetic pathway, with the exception being fumonisin B1; that male rats and mice are generally more susceptible than female rats and mice to chemical induction of renal tubule tumors; and that a background of atypical tubule hyperplasia is a useful indicator reflecting a chemically associated renal tubule tumor response. With respect to renal tubule tumors and human risk assessment, chemicals in categories 1 and 2, and possibly 3, would currently be judged by linear default methods; chemicals in category 4 (and probably some in category 3) as exhibiting a threshold of activity warranting the benchmark approach; and those in categories 5 and 6 as representing mechanisms that have no relevance for extrapolation to humans.
PMID: 15239388 [PubMed - indexed for MEDLINE]
71. Toxicology. 2004 Jul 1;199(2-3):251-9.
Ochratoxin A and some of its derivatives modulate radical formation of porcine blood monocytes and granulocytes.
Müller G, Burkert B, Möller U, Diller R, Rohrmann B, Rosner H, Köhler H.
Federal Research Centre for Virus Diseases of Animals, Naumburger Strasse 96a, D-07743 Jena, Germany.
Modulating effects of ochratoxin A (OTA) and some of its derivatives on viability and oxidative burst activity of porcine monocytes and granulocytes have been studied. The formation of free oxygen radicals by monocytes was suppressed by OTA and ochratoxin C (OTC) at concentrations between 10 and 1000 ng/ml. Intracellular radical formation of granulocytes was in part already significantly reduced at 1 ng/ml of these mycotoxins. Conversely, the intracellular formation of radicals in monocytes of individual pigs was stimulated by the toxins at 1-100 ng/ml. A biologically active fraction of the crude toxin (RE2) which had been identified as OTC had a stronger effect than all other derivatives of ochratoxin A. Whether these modulating effects of OTA and OTC on phagocyte functions are of significance in the pathogenesis of infectious diseases, needs to be studied in more detail. In this context, the occurrence of OTC in food and feeds should be examined more closely.
PMID: 15147798 [PubMed - indexed for MEDLINE]
72. Biochem Pharmacol. 2004 Mar 15;67(6):1195-202.
Mediation of annexin 1 secretion by a probenecid-sensitive ABC-transporter in rat inflamed mucosa.
Wein S, Fauroux M, Laffitte J, de Nadaï P, Guaïni C, Pons F, Coméra C.
Institut National de Recherche Agronomique, UR66, 180 Chemin de Tournefeuille, BP3, 31931 Toulouse Cedex 9, France.
Annexin 1 is secreted by mammalian cells but lacks a leader signal sequence necessary to lead it to the classical secretory pathway via the endoplasmic reticulum. The mechanisms involved in the secretion of leaderless proteins remain uncertain. It has been suggested to involve membrane translocation via an ABC-transporter (ATP binding cassette). Using cultured inflamed mucosa from rectocolitis induced in rats, we studied if annexin 1 secretion followed the two main characteristics of ABC-transporter substrates: dependency on ATP hydrolysis and competitive inhibition by several other ABC-transporter substrates. Annexin 1 secretion is inhibited in a dose-dependent manner by two ATPase inhibitors. The inhibition reached 63.2+/-3.2%, 66.1+/-3.73% and 88.6+/-1.4% in the presence of 2mM vanadate, 0.5 and 1mM pervanadate, respectively. The efflux of calcein, a known ABC-transporter substrate, is similarly inhibited by 69.4+/-2.8% in the presence of 1mM pervanadate. Probenecid, an inhibitor of several ABC-transporters of the subfamilly ABCC or MRP (multidrug resistant associated protein), also inhibited annexin 1 secretion in a dose-dependent manner. As compared to control, 10mM probenecid reduced annexin 1 secretion by 72+/-20% and 20mM by 95.0+/-9%. By contrast, annexin 1 secretion is not blocked by other inhibitors of MRP1 (indomethacin, MK571), MRP2 (ochratoxin A1 or MK571), MRP5 (trequinsin or sulfinpyrazone) or by verapamil, cyclosporin A or glyburide. Taken together, our results show that annexin 1 secretion appears to share the efflux properties of ABC-transporter substrates.
PMID: 15006554 [PubMed - indexed for MEDLINE]
73. J Biochem Mol Toxicol. 2004;18(1):43-9.
New insights into the mechanisms involved in renal proximal tubular damage induced in vitro by ochratoxin A.
Gennari A, Pazos P, Boveri M, Callaghan R, Casado J, Maurici D, Corsini E, Prieto P.
ECVAM, Institute for Health & Consumer Protection, Via Fermi 1, 21020 Ispra (Va), Italy.
The mycotoxin ochratoxin A is a contaminant of human and animal food products. It is a potent nephrotoxin known to damage the proximal tubule. The aim of this work was to investigate the effects of ochratoxin A on a porcine renal proximal tubular epithelial cell line (LLC-PK1), and to identify sensitive endpoints revealing damage at the epithelial barrier level and at the molecular level. Cells exposed for 24 h to 5-10 microM ochratoxin indicated a clear damage to the intactness of the epithelial barrier, as shown by measurements of trans-epithelial resistance and zonula occludens-1 protein expression. At the mitochondrial level we observed alterations of the normal functions, such as an increase of the membrane potential, the formation of straight extensions, and the formation of giant mitochondria. At higher ochratoxin concentrations (50 microM), at which cytotoxicity assays revealed a significant toxicity, alterations of the cytoskeleton organization and induction of apoptosis were evident. In addition, we analyzed the expression of genes by using a cDNA macroarray. Our data indicate that ochratoxin-induced nephrotoxicity can be detected at the barrier and at the mitochondrial level at rather low concentrations, at which conventional cytotoxicity assays are unable to reveal toxic effects.
Copyright 2004 Wiley Periodicals, Inc.
PMID: 14994279 [PubMed - indexed for MEDLINE]
74. Nephron Physiol. 2004;96(1):P19-25.
Increased renal fibrosis and expression of renal phosphatidylinositol 4-kinase-beta and phospholipase C(gamma1) proteins in piglets exposed to ochratoxin-A.
Aukema HM, House JD, Bankovic-Calic N, Ogborn MR.
Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada.
Endemic nephropathy has been linked to exposure of ochratoxin-A (OA) in grains and animal products. The underlying events surrounding this form of renal injury are not well known, partly due to the lack of a suitable animal model of the disease. Therefore, in this study, a pig model of OA-induced renal injury was established and used to examine whether elements of the phosphoinositide signalling pathway are altered in this disease. Weanling piglets were fed diets containing 0, 2, and 4 ppm OA for 6 weeks. Serum creatinine and urea and renal fibrosis were monitored biweekly using serial blood samples and renal biopsies. At termination, the protein levels of renal phosphatidylinositol 4-kinase-beta (PtdIns4Kbeta) and phospholipase C(gamma1) (PLC(gamma1)) were determined using immunoblotting and scanning densitometry. Serum creatinine was elevated by 2 weeks and renal fibrosis was elevated by 4 weeks at both levels of inclusion of OA. At the end of the experimental period, kidney size and water content were elevated, as were the protein levels of renal PtdIns4Kbeta and PLC(gamma1) in OA-exposed animals. Therefore, serial biopsies can be used to track changes in renal pathology in the OA-exposed piglet. We conclude that this is a useful model for OA-induced renal injury in which the underlying molecular events associated with this form of renal injury can be studied.
Copyright 2004 S. Karger AG, Basel
PMID: 14752240 [PubMed - indexed for MEDLINE]
75. Toxicol Appl Pharmacol. 2003 Nov 1;192(3):222-30.
Ochratoxin A affects COS cell adhesion and signaling.
Scibelli A, Tafuri S, Ferrante MC, Alimenti E, Naso B, Lucisano A, Staiano N, Della Morte R.
Dipartimento di Patologia e Sanità Animale, Università di Napoli Federico II, 80137 Napoli, Italy.
Ochratoxin A (OTA), a metabolite produced by strains of Aspergillus and Penicillium, has nephritogenic, carcinogenic, and teratogenic activity in animals and humans. Nanomolar concentrations of OTA promote apoptosis in a cell-type specific fashion. In this study, we have analyzed the molecular mechanism by which OTA affects COS cell adhesion and signaling resulting in an apoptotic response. OTA, at noncytotoxic doses, was able to detach collagen- and fibronectin-adherent cells from immobilized substratum. However, prior to inducing detachment of adherent cells, OTA caused apoptosis as measured by caspase-3 activation. The treatment of adherent cells by OTA caused a reduction of tyrosine phosphorylation levels of FAK and of the adapter protein paxillin. The down-regulation of FAK preceded apoptosis and cell detachment induced by OTA. The mycotoxin was also able to cause a decrease of the phosphorylation levels of the two Shc isoforms, P66 and P52, in adherent cells. Since these Shc isoforms have been implicated in the activation of protein kinase c-Src, which is required for FAK tyrosine phosphorylation, the observed dephosphorylation of FAK and of the FAK substrate paxillin by OTA could be ascribed to the early down-regulation of Shc isoforms. However, whether FAK and Shc phosphorylation contribute both to the same pathway leading to the induction of apoptosis by OTA or are involved in two parallel signaling pathways remains to be investigated.
PMID: 14575639 [PubMed - indexed for MEDLINE]
76. Hum Exp Toxicol. 2003 Jul;22(7):383-91.
Histopathologic changes in liver and renal tissues induced by Ochratoxin A and melatonin in rats.
Aydin G, Ozçelik N, Ciçek E, Soyöz M.
Department of Pathology, Süleyman Demirel University, School of Medicine, Isparta, Turkey. email@example.com
Nephrotoxicity and hepatotoxicity induced by Ochratoxin A (OTA) and ameliorating effects of melatonin were investigated in rats exposed to OTA. Experimental groups were as follows: control; OTA-treated; and OTA plus melatonin (MEL)-treated (OTA+MEL). The rats in the control group were administered with only a daily oral administration of 0.5 M NaHCO3. OTA was administered with a dose of 289 microg/kg in the same way. OTA and MEL were administered orally with OTA (289 microg/kg) and melatonin (10 mg/kg) in two different periods of time during the same day. The histopathologic changes in the liver and kidney tissues of control, OTA and OTA+MEL-treated rats were examined. There were no significant changes in the kidney and liver tissues of the control rats. Significant histopathologic changes were found in the kidney and liver tissue of rats treated with OTA. These were granular or vacuolated degeneration and necrosis of the liver cells, sinusoidal and central vein dilatation, bile duct proliferation, enlargement of periportal areas with mononuclear cell inflammatory infiltration and mild degree fibrous tissue proliferation, tubular epithelial cells degeneration, necrosis, proliferation and karyomegaly in the epithelial cells nuclei and peritubular and periglomerular lymphocyte infiltration, stromal fibrous tissue proliferation, hyperemic vessels. The severity of the lesions was significantly reduced by administration of melatonin. These results revealed that OTA induced significant histopathologic changes in liver and kidney tissue advocating OTA toxicity (P < 0.001), and administration of MEL+OTA significantly reduced the toxic effect of OTA on kidney and liver tissue of rats (P > 0.05).
PMID: 12929728 [PubMed - indexed for MEDLINE]
77. Toxicol Lett. 2003 Apr 30;142(1-2):19-27.
Lack of effects of sodium 2-mercaptoethane sulfonate (mesna) on Ochratoxin A induced renal tumorigenicity following life-time oral administration of Ochratoxin A in DA and Lewis rats.
Son WC, Kamino K, Lee YS, Kang KS.
Huntingdon Life Sciences, Huntingdon, Cambridgeshire, UK.
Comment in Toxicol Lett. 2005 Apr 10;156(2):315; author reply 317.
Sodium 2-mercaptoethane sulfonate (Mesna) reacts with urotoxic metabolites of oxazaphosphorine drugs (e.g. cyclophosphamide or ifosfamide) and has been used clinically to protect against damage induced by these aggressive anti-neoplastic drugs in the kidney and lower urinary and genital tracts. Ochratoxin A (OTA) is a potent nephrotoxin in several species. In order to elucidate whether mesna has curative or preventive effects on OTA-induced renal damage or renal tumor development, we administered OTA and/or mesna to both DA and Lewis rats for their life-time and examined kidney, urethra and urinary bladder histologically. OTA induced sex- and strain-specific renal tumors. However, there was no evidence of any effect of mesna on the incidence and distribution of any type of tumor or non-neoplastic finding in the kidney in either strain or treated group. In this study, we have confirmed that mesna treatment did not show any curative or preventive effects on either OTA-induced kidney damage or renal tumor development in two different strains that have distinct metabolic characteristics.
PMID: 12765235 [PubMed - indexed for MEDLINE]
78. Exp Toxicol Pathol. 2003 Mar;54(4):305-12.
Comparative responses to mode of oral administration and dose of ochratoxin A or nephrotoxic extract of Penicillium polonicum in rats.
Miljkovic A, Pfohl-Leszkowicz A, Dobrota M, Mantle PG.
Biochemistry Department, Imperial College of Science, Technology and Medicine, London, UK.
Administration of Penicillium polonicum extract to male Sprague-Dawley rats (200 g), either mixed in feed or given daily by gavage, for 5 days, had no clinical effects. However, at necropsy on day 6 marked histopathological changes occurred in renal tubule epithelia, including mitotic figures, karyomegalic nuclei, and frequent apoptosis identified specifically by TUNEL methodology and confocal microscopy. Ochratoxin A given similarly to rats (daily, 1 mg or 0.2 mg) was also clinically asymptomatic except for the 1 mg dose given by gavage; rats in this group lost weight. Marked renal tubular necrosis, though even without any significant accompanying apoptosis, was evident only at this higher dose by gavage; it was associated also with the highest incidence of renal DNA adducts and a disproportionately high concentration of ochratoxin A in plasma on day 6. Significantly fewer renal DNA adducts were detected in rats given 1 mg ochratoxin A in feed. The study demonstrates the potential for exaggerated toxicological responses to ochratoxin A administered by gavage through predicted consequential surges in the circulating concentration of the mycotoxin.
PMID: 12710714 [PubMed - indexed for MEDLINE]
79. Int J Cancer. 2003 Jun 20;105(3):305-11.
Strain-specific mammary proliferative lesion development following lifetime oral administration of ochratoxin A in DA and Lewis rats.
Son WC, Kamino K, Lee YS, Kang KS.
College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
Comment in Int J Cancer. 2004 Dec 20;112(6):1083.
OTA, a potent nephrotoxin in several species, is a renal carcinogen in animals and is implicated in the etiology of BEN. The NTP classified OTA as having clear evidence of carcinogenic activity, based on uncommon tubular adenomas and tubular cell carcinomas of the kidney and multiple fibroadenomas of the mammary gland, seen in the rat. As shown previously (Castegnaro et al., Int J Cancer 1998;77:70-5), induction of renal tumors by OTA is sex- and strain-specific in DA and Lewis rats, with DA males being most responsive and DA females being resistant; however, that report was confined to the kidney and urinary tract. To obtain OTA-induced tumorigenic information in rats, we administered OTA (0.4 mg/kg) by oral gavage to both DA and Lewis rats for their lifetimes and extended the investigation to complete histopathology of all tissues and organs. We also observed the characteristic renal tumor that is highly strain- and sex-specific, and there were increased incidences of proliferative mammary lesions in Lewis rats but not in DA rats, indicating that these were also strain-specific. In view of the NTP report of OTA treatment-related mammary fibroadenoma in F344 rats, we observed increased mammary proliferative lesions in Lewis rats but not in DA rats. Our results suggest that OTA may play some role in mammary tumor development in some rat strains.
Copyright 2003 Wiley-Liss, Inc.
PMID: 12704662 [PubMed - indexed for MEDLINE]
80. Toxicol Sci. 2003 Jun;73(2):315-28. Epub 2003 Apr 15.
A new approach to studying ochratoxin A (OTA)-induced nephrotoxicity: expression profiling in vivo and in vitro employing cDNA microarrays.
Luhe A, Hildebrand H, Bach U, Dingermann T, Ahr HJ.
Department of Molecular and Genetic Toxicology, Bayer AG, Aprather Weg 18a, 42096 Wuppertal, Germany. firstname.lastname@example.org
Ochratoxin A (OTA) is a mycotoxin often found in cereals as a contaminant, and it is known to cause severe nephrotoxicity in animals and humans. There have been several investigations studying the mode of action of this toxicant, suggesting inhibition of protein synthesis, formation of DNA adducts, and provocation of DNA single-strand breaks as a result of oxidative stress, but little is known about the transcriptional alterations underlying OTA-derived nephrotoxicity so far. We carried out DNA microarray analyses to assess OTA-specific expression profiles in vivo and in vitro. Cultures of primary rat proximal tubular cells and male Wistar rats were treated with a low dose (5 microM and 1 mg/kg, respectively) or a high dose (12.5 microM and 10 mg/kg, respectively) of OTA for 24 or 72 h. Microarray experiments were carried out after dual fluorescent labeling of sample cDNA, and data analysis was performed utilizing different statistical methods. Validity of selected microarray data was confirmed by quantitative real-time PCR. We were able to demonstrate that microarray data derived from our proximal tubule cell (PTC) culture model were highly comparable to the in vivo situation. Marked treatment-specific transcriptional changes were detected for genes involved in DNA damage response and apoptosis (upregulation of GADD 153, GADD 45, annexin V), response to oxidative stress (differential expression of hypoxia-inducible factor 1 and catalase), and inflammatory reactions (upregulation of alpha 2 macroglobulin, ceruloplasmin, and cathepsin S). We conclude that our results provide a molecular basis for interpretation of OTA-induced nephrotoxicity.
PMID: 12700408 [PubMed - indexed for MEDLINE]
81. Kidney Int. 2003 May;63(5):1725-35.
Inhibition of mitochondria prevents cell death in kidney epithelial cells by intra- and extracellular acidification.
Schwerdt G, Freudinger R, Schuster C, Silbernagl S, Gekle M.
Physiologisches Institut, Universität Würzburg, Würzburg, Germany. gerald email@example.com
BACKGROUND: Nephrotoxic substances like cisplatin or ochratoxin A (OTA) induce cell death in human proximal tubule-derived cells (IHKE cells). Mitochondria play a significant role in apoptosis and loss of their function may influence OTA- or cisplatin-induced apoptosis. Extracellular pH also plays an important role in tumor genesis. Therefore, we investigated the role of mitochondria and intra- and extracellular pH on cell death induction by cisplatin or OTA. METHODS: IHKE cells were incubated in the presence of OTA or cisplatin, together with inhibitors of the mitochondrial metabolism, and the activity of caspase-3 was measured and DNA laddering was monitored. Adenosine triphosphate (ATP) content of the cells, lactate release into the media, and glucose consumption was determined. In addition, media and cells were acidified or alkalized artificially to investigate the effect of intra- and extracellular pH on cell death induction. Cytochrome C was immunodetected in cellular compartments. RESULTS: Inhibition of the mitochondrial function reduced OTA- or cisplatin-induced cell death and led to considerable lactic acid production and extracellular acidification. Intra- and extracellular acidification prevented cells from cell death induced by OTA or cisplatin. No cytochrome C release from mitochondria could be detected during 24 hours of exposure to OTA or cisplatin. CONCLUSION: We conclude that OTA- or cisplatin-induced cell death is dependent on functional and intact, ATP-producing mitochondria and that intra- and extracellular pH is crucial for induction of cell death in IHKE cells.
PMID: 12675848 [PubMed - indexed for MEDLINE]
82. Kidney Blood Press Res. 2002;25(6):341-53.
Multifactorial determination of hypertensive nephroangiosclerosis.
Tylicki L, Rutkowski B, Hörl WH.
Department of Internal Medicine, Nephrology and Transplantology, Medical University, Gdansk, Poland.
Essential hypertension causes renal injury. Hypertensive nephroangiosclerosis (HN) or hypertensive nephropathy are terms most commonly used to describe this renal pathology. Although specific histological lesions occurring in affected kidneys are well known, pathogenesis of hypertension-related renal scarring is not completely understood. Evidence exists to support the theory that other factors such as aging, black race or smoking, beside blood pressure, contribute to the development and progression of HN. Metabolic disturbances, cocaine and nonsteroidal anti-inflammatory drug abuse, ochratoxin A exposure, dietary salt intake, heavy metal toxicity, hantavirus infection and perinatal programming are also considered risk factors. Renal susceptibility genes may determine whether hypertension-induced progressive renal damage occurs and how severe it is. Determination of all risk factors may identify patients at high risk of renal failure and help tailor an appropriate management. In the present paper, the knowledge available on this clinically important objective is discussed.
Copyright 2002 S. Karger AG, Basel
PMID: 12590197 [PubMed - indexed for MEDLINE]
83. Exp Toxicol Pathol. 2002 Aug;54(2):151-9.
Species- and sex-specific variations in binding of ochratoxin A by renal proteins in vitro.
Heussner AH, O'Brien E, Dietrich DR.
Environmental Toxicology, University of Konstanz, Germany.
The mycotoxin ochratoxin A (OTA) is a potent renal carcinogen in rodents and induces renal fibrosis in pigs. Furthermore, OTA has been associated with the development of renal tumors and nephropathies in humans. Large species- and sex-differences are observed in sensitivity toward OTA-mediated toxicity and carcinogenicity, yet neither the mechanism(s) resulting in OTA toxicity nor the reasons for the observed species- and sex-specificities are known. This paper investigated variations in OTA handling viz binding to renal proteins which could possibly explain the observed differences in OTA susceptibility in vivo and in vitro. The results obtained via a modification of a standard receptor-binding assay demonstrated the presence of at least one homogeneous binding component in renal cortical homogenates from pig, mouse, rat and humans. This component was shown to bind OTA in a specific and saturable manner. A range of compounds selected for their affinity for steroid receptors and/or for various known organic anion transporters were employed in a competition assay to answer the question whether this homogenous OTA binding component represents a steroid-like receptor component or one of the known organic anion transporters of the kidney. Although many of the compounds were able to compete with OTA for protein-binding, the competition patterns displayed a distinct species specificity and did not correspond to the competition patterns associated with presently known organic anion transporters of the kidney in the mouse, rat or human. The data thus suggests the presence of a new organic anion transporter or more likely, a cytosolic binding component of unknown function with high affinity and capacity for OTA binding in humans, rats, mice and possibly pigs.
PMID: 12211636 [PubMed - indexed for MEDLINE]
84. Mutagenesis. 2002 Jul;17(4):265-77.
Aristolochic acid as a probable human cancer hazard in herbal remedies: a review.
Arlt VM, Stiborova M, Schmeiser HH.
Section of Molecular Carcinogenesis, Institute of Cancer Research, Cotswold Road, Sutton, Surrey SM2 5NG, UK. firstname.lastname@example.org
The old herbal drug aristolochic acid (AA), derived from Aristolochia spp., has been associated with the development of a novel nephropathy, designated aristolochic acid nephropathy (AAN), and urothelial cancer in AAN patients. There is clear evidence that the major components of the plant extract AA, aristolochic acid I (AAI) and aristolochic acid II (AAII), both nitrophenanthrene carboxylic acids, are genotoxic mutagens forming DNA adducts after metabolic activation through simple reduction of the nitro group. Several mammalian enzymes have been shown to be capable of activating both AAI and AAII in vitro and in cells. The activating metabolism has been elucidated and is consistent with the formation of a cyclic nitrenium ion with delocalized charge leading to the preferential formation of purine adducts bound to the exocyclic amino groups of deoxyadenosine and deoxyguanosine. The predominant DNA adduct in vivo, 7-(deoxyadenosin-N(6)-yl)aristolactam I (dA-AAI), which is the most persistent of the adducts in target tissue, is a mutagenic lesion leading to AT-->TA transversions in vitro. This transversion mutation is found at high frequency in codon 61 of the H-ras oncogene in tumours of rodents induced by AAI, suggesting that dA-AAI might be the critical lesion in the carcinogenic process in rodents. DNA-binding studies confirmed that both AAs bind to the adenines of codon 61 in the H-ras mouse gene and preferentially to purines in the human p53 gene. In contrast, the molecular mechanism of renal interstitial fibrosis in humans after chronic administration of AA remains to be explored. However, preliminary findings suggest that DNA damage by AA is not only responsible for the tumour development but also for the destructive fibrotic process in the kidney. It is concluded that there is significant evidence that AA is a powerful nephrotoxic and carcinogenic substance with an extremely short latency period, not only in animals but also in humans. In particular, the highly similar metabolic pathway of activation and resultant DNA adducts of AA allows the extrapolation of carcinogenesis data from laboratory animals to the human situation. Therefore, all products containing botanicals known to or suspected of containing AA should be banned from the market world wide.
PMID: 12110620 [PubMed - indexed for MEDLINE]
85. Exp Toxicol Pathol. 2002 Feb;53(6):481-7.
Experimental one year ochratoxin A toxicosis in pigs.
Stoev SD, Paskalev M, MacDonald S, Mantle PG.
Department of General and clinical pathology, Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria.
Mild mycotoxic nephropathy was induced in 6 pigs by a diet containing ochratoxin A at 800 ppb, several times higher than that naturally encountered in some feed for pig production in Bulgaria. The nephropathy was expressed only as slightly hypertrophied kidneys with a faintly mottled surface, discernible at the end of the experiment to a skilled observer but probably not recognisable in routine slaughterhouse processing. Histological examination showed two types of changes: degenerative - affecting epithelial cells in some proximal tubules of pigs after 6 months, and proliferative changes in the interstitium which predominated after 1 year of exposure to ochratoxin A. Telangiectasis and lymph stasis were rarely seen. The renal lesions were similar to those described for classical mycotoxic porcine nephropathy formerly encountered in Denmark, but they were rather different from the porcine nephropathy which occurs spontaneously in Bulgaria. Measurement of ochratoxin A in serum provided analytical values complementary to feed intake and with similar concentration values. It also showed both accumulation with time, from 3 months to 6 months (approximately 1 ppm), and a 2-fold range of values within a group eating from a common feed source, as in commercial pig production. Mild symptomatology in this long, single-mycotoxin experiment serves to lessen somewhat the current perception of the direct renal toxicity of ochratoxin A alone, though a role in multi-toxin contexts is unquestioned.
PMID: 11926291 [PubMed - indexed for MEDLINE]
86. Adv Exp Med Biol. 2002;504:3-17.
Biology and ecology of mycotoxigenic Aspergillus species as related to economic and health concerns.
Wilson DM, Mubatanhema W, Jurjevic Z.
Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton 31793, USA.
The fungal genus Aspergillus was established in 1729, and includes species that are adapted to a wide range of environmental conditions. Many aspergilli produce mycotoxins in foods that may be toxic, mutagenic or carcinogenic in animals. Most of the Aspergillus species are soil fungi or saprophytes but some are capable of causing decay in storage, disease in plants or invasive disease in humans and animals. Major agricultural commodities affected before or after harvest by fungal growth and mycotoxins include corn, peanuts, cottonseed, rice, tree nuts, cereal grains, and fruits. Animal products (meat, milk and eggs) can become contaminated because of diet. Aspergillus flavus, A. parasiticus, A. ochraceus, A. niger, A. fumigatus and other aspergilli produce mycotoxins of concern. These include the aflatoxins and ochratoxins, as well as cyclopiazonic acid, patulin, sterigmatocystin, gliotoxin, citrinin and other potentially toxic metabolites.
PMID: 11922097 [PubMed - indexed for MEDLINE]
87. Toxicon. 2002 Mar;40(3):273-82.
Determination of the epigenetic effects of ochratoxin in a human kidney and a rat liver epithelial cell line.
Horvath A, Upham BL, Ganev V, Trosko JE.
Department of Chemistry and Biochemistry, Medical University of Sofia, Sofia, Bulgaria.
Epidemiological studies have implicated ochratoxin A (OTA), a fungal metabolic-contaminant of animal and human food sources, in Balkan Endemic Nephropathy and renal tumors. Many environmental toxicants operate through nongenotoxic mechanisms that epigenetically control gene expression leading to a diseased state. Gap junctional intercellular communication (GJIC) plays a central role in the epigenetic control of genes in which alteration of normal GJIC has been implicated in many human pathologies, including cancer, teratogenesis, reproductive dysfunction and peripheral neuropathies. The cell proliferative stages of human diseases, such as cancer, also involves the induction of signal transduction pathways controlling the mitogenic steps, in which the mitogen activated protein kinases (MAPK), such as extracellular receptor kinase (ERK) and p38, are central to mitogenesis. We therefore determined the effects of OTA on GJIC and MAPK in a human kidney and rat liver epithelial cell line. OTA reversibly inhibited GJIC at noncytotoxic doses in the rat liver but not the human kidney cell line. Similarly, OTA was also a strong activator of MAPK, ERK and p38, in the rat liver cells but only weakly activated ERK and had no affect on p38 in the human kidney cell line. Another hallmark of human diseases is an abnormal alteration of apoptosis, also known as programmed cell death. We used our myc-transfected cell line, which exhibits higher levels of apoptosis, to test the effects of OTA on apoptosis. OTA greatly induced apoptosis in this cell line, which is contrary to the effects of most tumor promoters. In summary, OTA exhibits tumor promoting properties in the liver, but the effects of OTA on the human kidney epithelial cells suggested a lack of tumorigenic activity assuming that these epithelial cells, like the rat liver epithelial cells, are a primary target for carcinogens. These results also indicate that the nephrotoxicity of OTA either does not involve GJIC, assuming these epithelial cells play a vital role in kidney physiology, or that a more differentiated kidney cell type is the target for OTA toxicity, of which the role of GJIC remains unknown.
PMID: 11711124 [PubMed - indexed for MEDLINE]
88. J Anim Physiol Anim Nutr (Berl). 2001 Aug;85(7-8):212-6.
Residues of ochratoxin A in pet foods, canine and feline kidneys.
Razzazi E, Böhm J, Grajewski J, Szczepaniak K, Kübber-Heiss AJ, Iben CH.
Institute of Nutrition, University of Veterinary Medicine, Vienna, Austria.
The occurrence of ochratoxin A (OTA) in canned (26 samples) as well as dry pet foods (17 samples) for cats and dogs was investigated. In addition, 26 feline kidney samples with or without kidney alterations were surveyed for OTA-residues. The separation and detection of OTA was carried out by an isocratic high-performance liquid chromatography system based on reversed phase with fluorescence detection. After homogenization and extraction steps, immuno-affinity columns were applied for sample clean up. OTA could be detected in 47% (n=40) of the pet food samples. Those found positive contained generally low amounts of OTA (0.1-0.8 microg/kg original substance). Higher levels were only detected in two pet food samples (3.2 and 13.1 microg/kg toxin, respectively). Low concentrations of ochratoxin A could also be found iIn tissue of cat kidneys, with 16 of the analysed kidneys (n=26) being positive. The concentration levels were between 0.35 and 1.5 microg/kg OTA in tissue. No relation between pathological findings and ochratoxin levels in feline kidneys could be assessed.
PMID: 11686791 [PubMed - indexed for MEDLINE]
89. Arch Toxicol. 2001 Jul;75(5):262-9.
Toxicokinetics of ochratoxin A in vervet monkeys (Cercopithecus aethiops).
Stander MA, Nieuwoudt TW, Steyn PS, Shephard GS, Creppy EE, Sewram V.
School of Chemistry and Biochemistry, University of Potchefstroom, South Africa.
The toxicokinetics of ochratoxin A were investigated in vervet monkeys (Cercopithecus aethiops). Three female monkeys were treated intravenously with ochratoxin A at doses, respectively, of 0.8, 1.5 and 2 mg/ kg body weight (BW). Blood and urine samples were collected over a period of 21 days. Plasma and urine extracts were analysed by high-performance liquid chromatography (HPLC) with either fluorescence or negative ion electrospray ionization mass spectrometric detection. The clearance of ochratoxin A from plasma followed a two-compartment model. The elimination half-life of ochratoxin A in the monkeys was determined to be 19-21 days and the average total body clearance was 0.22 +/- 0.07 ml/h per kg and the average apparent distribution volume of the central compartment was 59 +/- 9 ml/kg and the peripheral compartment was 59 +/- 20 ml/kg. No evidence was found for any metabolic conversion of ochratoxin A.
PMID: 11548118 [PubMed - indexed for MEDLINE]
90. Exp Toxicol Pathol. 2001 Jun;53(2-3):215-25.
Species- and sex-specific renal cytotoxicity of ochratoxin A and B in vitro.
Dietrich DR, O'Brien E, Stack ME, Heussner AH.
Environmental Toxicology, University of Konstanz, Germany. email@example.com
Four different cell models were chosen for comparison of OTA and OTB toxicity: primary porcine (PKC), rat (RPTC) and human renal proximal epithelial cells (HKC) from both sexes and a porcine renal cell line: LLC-PK1. Culture conditions were tested and optimized for each respective cell type (species/sex and origin). All cell types were characterized for epithelial origin and growth patterns and following optimization of dosing strategies and assay procedures, a strict study design was implemented to avoid systemic variations. Due to possible sensitivity differences, three simple endpoints were chosen to provide basic data for interspecies comparison: neutral red uptake, MTT reduction and cell number. Of the endpoints tested neutral red appeared the most sensitive, although all three parameters yielded comparable EC50's. Sex-differences were observed between male and female HKC cells following 96 h exposure to OTA, with HKC(m) being more sensitive than HKC(f). No sex-difference was observed in PKC cells, however, the PKC were approximately 3 and 10 times more sensitive than HKC(m) and HKC(f), respectively, to OTA and OTB. Interestingly, the CI95 of the EC50 values obtained for OTA (15.5-16.5 microM) and OTB (17.0-2 1.0 microM) were comparable in the PKC cells. In contrast, OTB had lower cytotoxicity than OTA in HKC and LLC-PK1 (approx. 2-fold) and no effects in RPTC. Overall, HKC(m) were nearly as sensitive as PKC towards OTA, followed by RPTC, LLC-PK1 and HKC(f), thus suggesting a sex specific sensitivity in humans towards OTA induced cytotoxicity.
PMID: 11484842 [PubMed - indexed for MEDLINE]
91. Arch Toxicol. 2001 May;75(3):176-83.
Aspartame prevents the karyomegaly induced by ochratoxin A in rat kidney.
Baudrimont I, Sostaric B, Yenot C, Betbeder AM, Dano-Djedje S, Sanni A, Steyn PS, Creppy EE.
UFR des Sciences Pharmaceutiques, Université Victor Segalen, Bordeaux, France. firstname.lastname@example.org
Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus ochraceus as well as other moulds. This mycotoxin contaminates animal feed and food. OTA is immunosuppressive, genotoxic, teratogenic, carcinogenic and is nephrotoxic in all animal species studied so far. OTA inhibits protein synthesis and induces lipid peroxidation. Since it seems impossible to avoid completely contamination of foodstuffs by toxigenic fungi, it is necessary to investigate the possible ways of limiting such toxicity. An attempt to prevent OTA-induced nephrotoxic and genotoxic effects, mainly the karyomegaly, has been made in vivo using aspartame (L-aspartyl-L-phenylalanine methyl ester), a structural analogue of both OTA and phenylalanine. Aspartame (25 mg/kg body weight) prevented most of the nephrotoxic effects induced by OTA (289 microg/kg body weight). It also showed some utility in preventing morphological and histological damage, mainly the karyomegaly. The protective effects of aspartame on OTA-induced nephrotoxicity could be based on several mechanisms related to competitive binding to plasma proteins, to transport or tissue distribution in the kidney or to the elimination of the toxin in the urine.
PMID: 11409539 [PubMed - indexed for MEDLINE]
92. Vet Res Commun. 2001 Apr;25(3):205-23.
Experimental mycotoxic nephropathy in pigs provoked by a diet containing ochratoxin A and penicillic acid.
Stoev SD, Vitanov S, Anguelov G, Petkova-Bocharova T, Creppy EE.
Department of Pathology, Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria.
Mycotoxic nephropathy was induced in 18 young pigs by diets contaminated with strains of Aspergillus ochraceus containing ochratoxin A (OTA) and penicillic acid (PA) at levels corresponding to those naturally encountered in animal feeds in Bulgaria. Haematological and biochemical parameters, as well as the morphological and ultrastructural changes in various internal organs, and especially in the kidneys, were examined at different stages of development of the disease. A mottled surface of the kidneys was only seen in pigs exposed to a mouldy diet containing 180 ppb OTA for 3 months, but microscopic lesions, as well as changes in various haematological and biochemical parameters, were observed in all groups exposed to the same mouldy diet containing only 90 or 180 ppb OTA. Histological examination showed two types of change: degenerative changes affecting the epithelial cells of the proximal tubules, which predominated at the initial stage, and proliferative changes in the interstitium, which predominated at the later stage of the disease. Telangiectasis and lymph stasis were also seen, as well as degenerative changes in the capillary endothelium. The characteristic renal lesions were similar to those observed in spontaneous cases of mycotoxic porcine nephropathy in Bulgaria, but they were a little different from the classic Danish porcine nephropathy. The enhanced toxicity of OTA in our study may be due to a synergistic effect between OTA and PA or to some other unknown metabolites produced by the same ochratoxinogenic strains of A. ochraceus.
PMID: 11334150 [PubMed - indexed for MEDLINE]
93. Toxicol Lett. 2001 Apr 8;121(1):9-13.
Ochratoxin A in human serum samples collected in Isparta-Turkey from healthy individuals and individuals suffering from different urinary disorders.
Ozçelik N, Koşar A, Soysal D.
Department of Medical Biology and Genetic, Süleyman Demirel University, School of Medicine, Eski Sümerbank cad. 31/A, 32040, Isparta, Turkey. email@example.com
Ochratoxin A (OA) is a nephrotoxic fungal metabolite (mycotoxin) occurring in foodstuffs. The compound is causally associated with mycotoxin porcine nephropathy, a disease comparable with a human kidney disease called endemic nephropathy. In this paper OA levels in the human serum samples collected from healthy individuals and individuals suffering from different urinary disorders in Isparta-Turkey are presented. OA was measured in serum samples of 40 healthy people and a total of 93 patients with different kinds of urinary disorders. Four different kinds of urinary disorders were represented: chronic renal failure treated by hemodialysis (35), chronic renal failure treated by peritoneal dialysis (28), patients with bladder cancer (15), patients with renal stones (15). Analysis of OA in human blood samples was performed using an analytical method based on the measurement of fluorescence spectra. The mean concentration of OA in the healthy group was 0.4 +/- 0.28 ng/ml. The highest mean concentration was found in the group of patients treated by hemodialysis, 2.1+/- 1.2 ng/ml. The mean concentrations of the toxin in all patients groups were higher compared to the control group. Also, a significant difference was found between the mean concentrations of the groups of patients treated by dialysis (hemodialysis or peritoneal dialysis) and of the patients with renal stones or bladder cancer, only with the exception of the difference between peritoneal dialysis and renal stones group. No other significant differences were found when comparing the two groups. The findings indicate that OA may have a role in the human urinary pathology considered herein. A higher level of OA in dialysis groups compared to the control, renal stones and bladder cancer groups could probably be explained by the reduced glomerular filtration rate of these patients.
PMID: 11312032 [PubMed - indexed for MEDLINE]
94. Food Chem Toxicol. 2001 Jan;39(1):55-65.
Age-related differences in the toxicity of ochratoxin A in female rats.
Dortant PM, Peters-Volleberg GW, Van Loveren H, Marquardt RR, Speijers GJ.
Laboratory of Pathology and Immunobiology, National Institute of Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, The Netherlands.
Ochratoxin A (OTA) is a mycotoxin found in food and feedstuffs of plant and animal origin. OTA exposure is related to nephropathy in humans. Age-related differences, especially in nephro- and immunotoxicity of OTA, were investigated in young adult (aged 12 weeks) and old (aged 27-30 months) female SPF Wag rats, treated by gavage with 0, 0.07, 0.34 or 1.68 mg OTA/kg body weight for 4 weeks. In both age groups, survival was significantly decreased in the highest dose group. Clinical condition, body weight, clinical chemistry parameters (ALAT, ASAT, creatinin and urea) and target organs (as identified by weight and pathology - kidney, liver, adrenals, forestomach and brain) were affected by age and dose, but often more severely in old than in young rats. OTA induced primarily nephropathy. Old rats were more sensitive to induction of tubular karyomegaly and vacuolation/necrosis. In young rats, OTA induced a dose-related thickening of the basement membrane and reduction in splenic T-cell fraction. Decreased IgG levels were seen at 0.34 mg/kg OTA (young and old rats) and 1.68 mg/kg OTA (young rats). Vacuolation of the white brain matter (cerebellar medulla and ventral parts of the brain stem) was significantly increased in young rats at 0.34 and 1.68 mg/kg OTA and in old rats at 0.07 and 0.34 mg/kg OTA. It was concluded that: (1) the profiles of OTA toxicity for both age groups are similar, with the kidney and possibly the brain being primary target organs; (2) based on clinical and pathological data old rats are more sensitive to OTA than young rats; and (3) the immune system is probably not the primary target of OTA toxicity.
PMID: 11259851 [PubMed - indexed for MEDLINE]
95. Ann Pharm Fr. 2000 Dec;58(6 Suppl):464-9.
[Mycotoxins. Contaminants of animal and human foods].
[Article in French]
U. P. de Pharmacie et Toxicologie, Ecole nationale vétérinaire d'Alfort, 7 Avenue du Général-de-Gaulle, F94704 Maisons-Alfort Cedex. Manuscrit reçu le 6 octobre 1999.
Mycotoxins are toxic products secreted by microscopic fungi. They can contaminate products of vegetal origin consumed by humans and cattle, therefore secondary by humans. The most important mycotoxins are aflatoxins, hepatotoxic and hepatocarcinogenic, and ochratoxins, nephrotoxic and nephrocarcinogenic. The maximal authorized limits of aflatoxin contents in human and animal food-stuffs are very low (few microg/kg or fractions of microg/kg).
PMID: 11148384 [PubMed - indexed for MEDLINE]
96. Exp Toxicol Pathol. 2000 Aug;52(4):287-96.
Susceptibility to secondary bacterial infections in growing pigs as an early response in ochratoxicosis.
Stoev SD, Goundasheva D, Mirtcheva T, Mantle PG.
Dept. of Pathomorphology, Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria. firstname.lastname@example.org
Mycotoxic nephropathy was induced in twelve 14 kg pigs fed a dietary component, moulded by Aspergillus ochraceus and contributing ochratoxin A at 1 or 3 ppm for up to 3 weeks. Concurrently, salmonellosis arose spontaneously in all six animals treated at 3 ppm and all died between days 15 and 17. Two of the six pigs in the 1 ppm group died similarly but the rest, and all of six control animals, were unaffected. Clinical biochemistry and histology revealed changes typical of renal ochratoxicosis in all ochratoxin-treated pigs. Clinical and pathomorphological changes typical of salmonellosis were evident in all those that died and Salmonella choleraesuis was consistently isolated from their faeces and liver. In a further experiment at 1 ppm ochratoxin A in animals immunised against S. choleraesuis haemorrhagic diarrhoea resulted instead, associated with Serpulina hyodysenteriae and Campylobacter coli. There was concomitant evidence of immunosuppression and delayed response to immunization. For the first time, susceptibility to natural infectious disease has been demonstrated in pigs exposed to the immunotoxicity of ochratoxin A. Differentiation of biochemical and histological changes attributable to ochratoxicosis or to secondary disease may require reinterpretation of a classical description of experimental porcine ochratoxicosis.
PMID: 10987179 [PubMed - indexed for MEDLINE]
97. N Engl J Med. 2000 Jun 8;342(23):1686-92.
Urothelial carcinoma associated with the use of a Chinese herb (Aristolochia fangchi)
Nortier JL, Martinez MC, Schmeiser HH, Arlt VM, Bieler CA, Petein M, Depierreux MF, De Pauw L, Abramowicz D, Vereerstraeten P, Vanherweghem JL.
Department of Nephrology, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium. email@example.com
Comment in N Engl J Med. 2000 Oct 26;343(17):1268-9; author reply 1269-70. N Engl J Med. 2000 Jun 8;342(23):1742-3. N Engl J Med. 2000 Oct 26;343(17):1269; author reply 1269-70. N Engl J Med. 2000 Oct 26;343(17):1269; author reply 1269-70.
BACKGROUND: Chinese-herb nephropathy is a progressive form of renal fibrosis that develops in some patients who take weight-reducing pills containing Chinese herbs. Because of a manufacturing error, one of the herbs in these pills (Stephania tetrandra) was inadvertently replaced by Aristolochia fangchi, which is nephrotoxic and carcinogenic. METHODS: The diagnosis of a neoplastic lesion in the native urinary tract of a renal-transplant recipient who had Chinese-herb nephropathy prompted us to propose regular cystoscopic examinations and the prophylactic removal of the native kidneys and ureters in all our patients with end-stage Chinese-herb nephropathy who were being treated with either transplantation or dialysis. Surgical specimens were examined histologically and analyzed for the presence of DNA adducts formed by aristolochic acid. All prescriptions written for Chinese-herb weight-reducing compounds during the period of exposure (1990 to 1992) in these patients were obtained, and the cumulative doses were calculated. RESULTS: Among 39 patients who agreed to undergo prophylactic surgery, there were 18 cases of urothelial carcinoma (prevalence, 46 percent; 95 percent confidence interval, 29 to 62 percent): 17 cases of carcinoma of the ureter, renal pelvis, or both and 1 papillary bladder tumor. Nineteen of the remaining patients had mild-to-moderate urothelial dysplasia, and two had normal urothelium. All tissue samples analyzed contained aristolochic acid-related DNA adducts. The cumulative dose of aristolochia was a significant risk factor for urothelial carcinoma, with total doses of more than 200 g associated with a higher risk of urothelial carcinoma. CONCLUSIONS: The prevalence of urothelial carcinoma among patients with end-stage Chinese-herb nephropathy (caused by aristolochia species) is a high.
PMID: 10841870 [PubMed - indexed for MEDLINE]
98. Nat Toxins. 1999;7(4):167-73.
A French monitoring programme for determining ochratoxin A occurrence in pig kidneys.
Dragacci S, Grosso F, Bire R, Fremy JM, Coulon S.
Microbial Toxins Unit, French Agency for Food Safety (AFSSA) Paris, France. firstname.lastname@example.org
Ochratoxin A is a carcinogen and nephrotoxin which can enter the food chain resulting in human exposure. As pig herds are exposed to ochratoxin A through their feed, their kidneys, livers and pork meat are considered as a possible route of exposure for humans. France, an important producer of pork and pork products, set up a national monitoring programme which included the training of six routine public laboratories in the analysis of ochratoxin A using an immunoaffinity step followed by a HPLC-fluorimetric detection. The programme randomly sampled 300 healthy and 100 nephropathic pig kidneys in 1997 and 710 healthy pig kidneys in 1998. Less than 10% of samples were significantly contaminated by ochratoxin A : in the 1997 survey, 1% of samples contained 0.40-1.40 microg kg(-1) of ochratoxin A and in the 1998 survey 7.6 % exhibited ochratoxin A levels in the range 0.5-5 microg kg(-1). In the case of nephropathic kidneys, only traces of ochratoxin A (0.16 to 0.48 microg kg(-1)) were detected in six samples out of 100. Even if not a major route of exposure for humans, pigs are clearly exposed to this mycotoxin and monitoring of pork products and of feed for swine is necessary.
Copyright 1999 John Wiley & Sons, Ltd.
PMID: 10797645 [PubMed - indexed for MEDLINE]
99. Hum Exp Toxicol. 1999 Jun;18(6):410-5.
Karyomegaly of tubular cells as early stage marker of the nephrotoxicity induced by ochratoxin A in rats.
Maaroufi K, Zakhama A, Baudrimont I, Achour A, Abid S, Ellouz F, Dhouib S, Creppy EE, Bacha H.
Laboratoire de Biochimie et de Toxicologie Moléculaire, Faculté de Médecine Dentaire, Tunisia.
Cases of karyomegaly were described by Sclare and by Mihatch in patients affected with tubular-interstitial nephropathy. The Karyomegalic cells showed enlarged nuclei with accumulation of genetic material. No aetiology was suggested. Our study of rats experimentally intoxicated by ochratoxin A, a well-known nephrotoxic compound, indicates the presence of karyomegaly with alteration of the tubular tissue. In control animals no karyomegalic cells were detected. These observations suggest that karyomegaly with megacytosis may be caused by the nephrotoxic ochratoxin A in the kidney. In addition abnormal mitosis together with karyomegalic cells were observed at an earlier stage of the intoxication (30 days) suggesting possible regeneration if the OTA insults are stopped. After 90 days of treatment, the degeneration increased and only karyomegalic and apoptotic-like cells were observed indicating that the regeneration no longer occurs and that the degeneration becomes irreversible.
PMID: 10413246 [PubMed - indexed for MEDLINE]
100. Toxicol Lett. 1999 Jan 11;104(1-2):83-92.
The role of alpha2u-globulin in ochratoxin A induced renal toxicity and tumors in F344 rats.
Rásonyi T, Schlatter J, Dietrich DR.
Institute of Toxicology, Swiss Federal Institute of Technology (ETH) and University of Zurich, Schwerzenbach.
The mycotoxin ochratoxin A (OTA) was shown to be a potent kidney carcinogen in rats demonstrating a marked sex difference in the response. Compared to female rats, male rats had a 10-fold higher incidence of kidney carcinomas. The objective of this study was to investigate whether this sex difference in tumor response is due to an exacerbation of effect resulting from the interaction of the male rat specific urinary protein alpha2u-globulin (alpha2u) with OTA. Male and female rats were treated by oral gavage with OTA (1 mg/kg per day), D-limonene (dL; 1650 mg/kg per day) as a positive control or corn oil for 7 consecutive days. OTA induced severe renal lesions predominantly in the P3 region of the proximal tubules. The lesions consisted of necrotic cells and cell exfoliations. No hyaline droplets were found in the P2 segment following OTA treatment, whereas dL induced the expected accumulation of droplets. The results suggest that OTA induced kidney lesions are in all characteristic points different from the known alpha2u-nephropathy induced by dL. Based on these experiments the male rat specific protein alpha2u does not seem to be involved in the mechanism(s) leading to the high tumor incidence observed in OTA exposed male rats.
PMID: 10048753 [PubMed - indexed for MEDLINE]
101. Vet Hum Toxicol. 1998 Dec;40(6):352-60.
The role of ochratoxin A as a possible cause of Balkan endemic nephropathy and its risk evaluation.
Department of Pathomorphology, Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria.
This article presents evidences which support the mycotoxic hypothesis of Balkan endemic nephropathy (BEN), examines the significance of human exposure to ochratoxin A (OTA) in BEN-endemic areas, and gives some ideas for future investigations. The morphological and ultrastructural similarity between OTA-induced mycotoxic porcine nephropathy (MPN) and BEN, epidemiological studies, and relationship between the incidence of BEN and the presence of OTA in human blood in contamination levels similar to those in pigs suffering from MPN suggest that OTA could be an etiological factor in BEN.
PMID: 9830698 [PubMed - indexed for MEDLINE]
102. Lancet. 1998 Oct 3;352(9134):1118-9.
Does apoptosis cause renal atrophy in Balkan endemic nephropathy?
Mantle PG, Milijkovic A, Udupa V, Dobrota M.
PMID: 9798592 [PubMed - indexed for MEDLINE]
103. Toxicol Appl Pharmacol. 1998 Sep;152(1):282-91.
Characterization of an ochratoxin-A-dedifferentiated and cloned renal epithelial cell line.
Gekle M, Gassner B, Freudinger R, Mildenberger S, Silbernagl S, Pfaller W, Schramek H.
Department of Physiology, University of Würzburg, Würzburg, D-97070, Germany.
Ochratoxin A (OTA) is a ubiquitous fungal metabolite with predominant nephrotoxic action. OTA impairs postproximal renal electrolyte handling and increases the incidence of renal adenoma and carcinoma. Furthermore, it is supposed to be involved in the pathogenesis of different forms of human renal diseases. Previously we have shown that OTA activates extracellular signal-regulated kinase 1 (ERK1) and ERK2 in the C7 clone but not in the C11 clone of renal epithelial MDCK cells. Here we show that nanomolar concentrations of OTA lead to stable and irreversible phenotypical and genotypical alterations, resulting in sustained dedifferentiation of MDCK-C7 cells but not of MDCK-C11 cells. Dedifferentiated MDCK-C7 cells (OTA-C7 cells) display a distinct morphology from the parent cell line (spindle-shape, pleiomorphic, narrow intercellular spaces, increased cell size) and show a reduced proliferation rate and numerical chromosomal aberrations. Functionally, OTA-C7 cells are characterized by a dramatic reduction of transepithelial electrolyte transport and the complete loss of responsiveness to the mineralocorticoid hormone aldosterone. Our data provide further evidence that OTA can lead to cell dedifferentiation and eventually to transformation of cloned quiescent cells. The changes in phenotype due to this dedifferentiation could explain some of the OTA-induced changes in renal function.
Copyright 1998 Academic Press.
PMID: 9772224 [PubMed - indexed for MEDLINE]
104. Kidney Blood Press Res. 1998;21(2-4):277-9.
Tubulotoxic mechanisms of ochratoxin A.
Gekle M, Sauvant C, Schwerdt G, Silbernagl S.
Physiologisches Institut, Universität Würzburg, Deutschland. email@example.com
PMID: 9762856 [PubMed - indexed for MEDLINE]
105. Hum Exp Toxicol. 1998 Jul;17(7):380-6.
Subchronic effects of ochratoxin A on young adult rat brain and partial prevention by aspartame, a sweetener.
Belmadani A, Tramu G, Betbeder AM, Creppy EE.
Laboratory of Toxicology and Applied Hygiene, Bordeaux, France.
1. Ochratoxin A (OTA) is a mycotoxin produced by several fungi, especially Aspergillus and Penicillium species. Many food and foodstuffs can be contaminated by ochratoxin A, which is consequently found in blood of animals and humans. 2. The distribution into the brain of young adult rats fed OTA for 1 to 6 weeks and some consequences have been investigated in the present study. 3. Our results on rats given OTA (289 microg/kg/48 h) indicated that OTA accumulated in the whole brain as function of time according to a regression curve, Y=-8.723 a+16.72 with a correlation coefficient of r=0.989, where Y-axis is the OTA concentration in ng/g of brain and X-axis is the duration of the treatment in weeks. The brain OTA contents was 11.95 +/- 2.2, 23.89 +/- 4.4, 39.9 +/- 4.5, 50.3 +/- 7.3, 78.8 +/- 6.3, 94 +/- 16 ng/g of brain in the mycotoxin-treated animals for respectively 1, 2, 3, 4, 5 and 6-weeks treatment. OTA induced modifications of free amino-acid concentrations in the brain, mainly, Tyrosine (Tyr) and phenylalanine (Phe). Tyr decreased significantly as compared to control (p < 0.05). Phe increased significantly as compared to control (p < 0.05). 4. Aspartame, (25 mg/kg/48 h) a structural analogue of OTA largely modified the distribution and prevented the accumulation of OTA in the brain since the respective brain OTA contents decreased respectively to 9.6 +/- 7.9, 19.2 +/- 3.0, 26.8 +/- 4.2, 19.7 +/- 1.9, 13.7 /- 5.6 and 11.0 +/- 6.0 ng/g of tissue, for the same duration of treatment. It also prevented the modifications of Tyr and Phe levels. 5. The histological investigations showed several necrotic cells with pyknotic nucleus, detected in OTA treated animals with higher frequency as compared to the controls and Aspartame treated ones. Aspartame appeared to significantly prevent this nuclear effect as well, the meaning of which is discussed.
PMID: 9726534 [PubMed - indexed for MEDLINE]
106. Zentralbl Veterinarmed A. 1998 May;45(4):229-36.
Haematological, biochemical and toxicological investigations in spontaneous cases with different frequency of porcine nephropathy in Bulgaria.
Stoev SD, Stoeva JK, Anguelov G, Hald B, Creppy EE, Radic B.
Department of Pathomorphology, Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria.
Haematological, biochemical and toxicological investigations of blood and urine of normally slaughtered pigs exhibiting different frequency (1-2%, 10-20% and 50-60%) of changes characterized as "enlarged mottled kidneys", at the slaughtering meat inspection were carried out to elucidate the nature of nephropathies encountered in Bulgaria. A content of ochratoxin A, higher in the spring than the autumn, was found in the serum and urine samples. The mean contamination levels of ochratoxin A in consumed feeds ranged from 114 +/- 36 ppb for 1994 to 207 +/- 65 ppb for 1993. The renal changes were characterized by impairment of proximal tubular function (indicated by an increased urinary excretion of glucose and protein) as well as by decreased specific gravity and increased pH in the urine mainly in pigs with 50-60% frequency of nephropathy. The concentration of urea, creatinine and glucose in the blood was increased, whereas the serum protein and cholesterol were decreased in pigs with 10-20% and 50-60% frequency of nephropathy. The mean enzyme levels of gamma-glutamyl transpeptidase and leucine aminopeptidase were significantly increased in the urine. The presence of granular casts and necrotic renal tubular cells were established in the sediment.
PMID: 9697424 [PubMed - indexed for MEDLINE]
107. Vet Rec. 1998 Feb 21;142(8):190-4.
Porcine nephropathy in Bulgaria: a progressive syndrome of complex or uncertain (mycotoxin) aetiology.
Stoev SD, Hald B, Mantle PG.
Faculty of Veterinary Medicine, Thracian University, Stara Zagora, Bulgaria.
Macroscopic nephropathy was observed in 506 pigs at slaughter in Bulgaria in 1993/94. Histopathological changes were mainly degenerative and proliferative, and were linked with kidney hypertrophy similar to that of the classical Danish Syndrome. Retention cysts formed by dilated tubules, activation or proliferation of capillary and vascular endothelium, and the development of neoplastic tissue were also observed. The most advanced pathology took the form of extensive interstitial fibrosis. Traces of ochratoxin A were found in the kidneys of the majority of 96 cases examined, and in some feed samples taken retrospectively from farms or commercial sources. The dietary ochratoxin concentration (100 micrograms/kg), calculated from serum analyses, closely matched the average of individually analysed feeds. In other feeds no ochratoxin A was detected and the cosmopolitan mycobiota isolated did not include the ochratoxinogenic Penicillium verrucosum that caused the Danish syndrome. Aspergillus ochraceus was rare and the isolates did not synthesise ochratoxin in laboratory culture. The unconfirmed diagnosis of ochratoxicosis suggests a complex or multi-toxin aetiology for this rather common chronic disease in Bulgaria.
PMID: 9533281 [PubMed - indexed for MEDLINE]
108. J Toxicol Environ Health A. 1998 Feb 6;53(3):231-50.
Dietary cholestyramine reduces ochratoxin A-induced nephrotoxicity in the rat by decreasing plasma levels and enhancing fecal excretion of the toxin.
Kerkadi A, Barriault C, Tuchweber B, Frohlich AA, Marquardt RR, Bouchard G, Yousef IM.
Département de Nutrition, Université de Montréal, Québec, Canada.
Ochratoxin A (OTA) is a mycotoxin that may contaminate animal feed (oat, barley, and rye) and food (wheat, rice, coffee, beer, pig meat), leading to major health problems (e.g., nephropathy) in several animal species including humans. Several methods have been tested to reduce the toxicity of OTA in animals but with limited success. In rats, the effect of cholestyramine (CHA), a bile acid-binding resin, was investigated on OTA-induced nephrotoxicity and bioavailability. Animals were fed semisynthetic diets containing two levels of OTA: 1 or 3 ppm. At each level of OTA, the diets were enriched with 0.1, 1, and 5% of CHA. The results showed that CHA decreased the concentration of OTA in plasma. At 1 and 3 ppm of OTA in the diet, CHA is effective at a level of 0.1% and 5%, respectively. The excretion of OTA and its metabolites (ochratoxin alpha and hydroxylated ochratoxin A) in bile and urine was also decreased by addition of 5% CHA in the diet. This was associated with an increase of OTA excretion in feces. Enzymuria and renal morphology revealed that dietary CHA can decrease OTA-induced nephrotoxicity, probably by reducing renal exposure to the toxin. In conclusion, CHA can reduce OTA concentrations in plasma as well as reducing nephrotoxicity, which may be attributed to a decrease of bioavailability and/or enterohepatic circulation of the toxin.
PMID: 9482354 [PubMed - indexed for MEDLINE]
109. J Toxicol Environ Health. 1996 Jul;48(4):379-96.
Effects of mycotoxins on cytokine production and proliferation in EL-4 thymoma cells.
Marin ML, Murtha J, Dong W, Pestka JJ.
Department of Food Science and Human Nutrition, Michigan State University, East Lansing 48824-1224, USA.
The thymoma cell line EL4.IL-2 (EL-4) was used as a T-cell model to assess the immunotoxic effects of several mycotoxins produced by the Aspergillus-Penicillium and the Fusarium groups. EL-4 cells were stimulated with phorbol 12-myristate 12-acetate (PMA) in the presence of mycotoxins at various concentrations for 5 d and culture supernatants were analyzed for interleukins (IL) IL-2 and IL-5 by enzyme-linked immunosorbent assay (ELISA). The cytokine effects were further related to proliferation and cell viability using the MTT [3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay with absorbance at 570 nm (A570) as the endpoint indicator. IL-2 and IL-5 levels were dramatically increased by cyclopiazonic acid at 50-1000 ng/ml, whereas IL-2 was significantly decreased at 10 microgram/ml. Proliferation was slightly increased at 100-1000 ng/ml cyclopiazonic acid but markedly depressed at 5 and 10 microgram/ml. When EL-4 cells were exposed to 5 and 10 microgram/ml of ochratoxin A, IL-2 production was markedly increased while IL-5 production was significantly decreased. The A570 was significantly decreased by ochratoxin A at 10 microgram/ml. IL-2 and Il-5 production was almost totally suppressed by patulin at concentrations > or = 500 ng/ml and by T-2 toxin at > or = 5 ng/ml. These effects occurred concurrently with marked depression of A570 in the MTT assay. Although A570 was unaffected by either zearalenone or alpha-zearalenol exposure, both IL-2 and IL-5 levels were significantly elevated by these toxins at 5 or 10 microgram/ml. IL-2 and IL-5 production were not affected in EL-4 cells cultured with either the Aspergillus-Penicillium toxins aflatoxin B1 and secalonic acid or the Fusarium toxins wortmannin, fumonisin B1, or fusaric acid at concentrations up to 10 microgram/ml. In total, the EL-4 culture studies indicated that cyclopiazonic acid, ochratoxin A, zearalenone, and alpha-zearalenol could stimulate cytokine production whereas patulin and T-2 toxin were inhibitory. Cytokine dysregulation was not always related directly to perturbations in proliferation. The results suggest that the EL-4 thymoma cell line could be a simple and effective in vitro model for evaluating immunotoxicity of various classes of environmental chemicals.
PMID: 8691508 [PubMed - indexed for MEDLINE]
110. Kidney Blood Press Res. 1996;19(5):225-35.
Renal toxicodynamics of ochratoxin A: a pathophysiological approach.
Gekle M, Silbernagl S.
Department of Physiology, University of Würzburg, Germany.
Ochratoxin A (OTA) is a secondary fungal metabolite that has been detected in a variety of animal chows, human food and in up to 80% of human blood samples of several Western countries. Its main target is the kidney. OTA is the causing agent of Danish porcine nephropathy and increases the incidence of renal carcinomas and adenomas in rats. Pathophysiological studies revealed that OTA acts on different sites along the nephron. Acute OTA exposure leads to an impairment of postproximal nephron function, predominantly of the collecting duct, resulting in altered electrolyte and titratable acid excretion. The underlying mechanism is most probably a blockade of anion conductance in the plasma membrane at nanomolar concentrations of OTA with subsequent disturbance of cellular acid-base homeostasis as shown in cultured kidney cells. Disturbance of cellular pH homeostasis is probably also involved in OTA-induced transformation of cultured kidney cells. Chronic OTA exposure leads to an additional reduction in the urine concentrating ability. Renal hemodynamics and the secretory function of the proximal tubule are affected by OTA after prolonged but not by acute exposure. OTA increases resistance in the vas efferens with a subsequent decrease in renal blood flow and glomerular filtration rate. Proximal tubular cells respond to OTA with a dramatic reduction in the secretory capacity for organic anions. The resorptive capacity for small molecules like amino acids is affected only to a minor extent, whereas endocytic uptake of albumin is clearly reduced. Furthermore, OTA has a mitogenic potential on rat proximal tubular cells in primary culture if applied in nanomolar concentrations but inhibits cell growth at micromolar concentrations. According to the above-described effects OTA exerts a complex action on renal function depending on the dose and time of exposure. The high incidence of OTA in human food and blood samples taken together with its diverse effects on renal function should attract further attention to this mycotoxin as a possible candidate for renal malfunction of unknown origin in humans.
PMID: 8956233 [PubMed - indexed for MEDLINE]
111. Cell Biol Toxicol. 1995 Dec;11(6):355-66.
Activation markers and cell proliferation as indicators of toxicity: a flow cytometric approach.
Johannisson A, Thuvander A, Gadhasson IL.
Department of Pathology, Swedish University of Agricultural Sciences, Uppsala.
Cell proliferation is an attractive endpoint in in vitro toxicity assays, since nearly any kind of damage in a cell may result in altered cell proliferation. In toxicological applications, liquid scintillation counting, measuring radioactivity from tritiated thymidine, has been the traditional way to estimate cell proliferation. An alternative approach is the measurement of BrdU incorporation by flow cytometry. Before the actual DNA synthesis starts, several proteins are expressed on the cell surface, as well as intracellularly. Among the markers on the cell surface CD69, CD25, and CD71 are sequentially expressed on human lymphocytes after a mitogenic stimulation. The aim of this study was to evaluate information obtained by analysis of expression of activation markers on cell surfaces in lymphocyte subsets and to compare it with data from cell proliferation studies performed by liquid scintillation counting and BrdU flow cytometry. The experiments were performed with phytohemagglutinin-stimulated human lymphocytes exposed to ochratoxin A and cyclosporin A. While ochratoxin A-treated cultures showed a steep inhibition with increasing concentration, the cyclosporin A treatment gave an inhibition curve with a less steep slope. Activation marker studies showed that the effect of treatment with both of the toxins was more pronounced on the late markers CD25 and CD71, while CD69 had the advantage that significant effects could be detected as early as 6 h after ochratoxin A treatment. Cyclosporin A treatment induced only minor alterations in CD69 expression. Certain differences in expression of activation markers between CD4+ and CD8+ subsets were found both in ochratoxin A- and cyclosporin A-treated cultures. A stimulating effect was found in cell cultures exposed to the lowest concentration of ochratoxin A on CD69 and CD25 expression. Signs of an increase in frequencies of proliferating cells measured with the BrdU flow cytometry method were also seen. This increase could not be detected with liquid scintillation counting. No other differences between the liquid scintillation counting and BrdU flow cytometry measurements of proliferation were obtained. We conclude that studies of activation marker expression by the flow cytometric approach used in this report are useful complements to traditional measurements of cell proliferation as they yield subset-specific information about cellular processes which precede proliferation of lymphocytes.
PMID: 8788211 [PubMed - indexed for MEDLINE]
112. J Pharmacol Exp Ther. 1995 Oct;275(1):397-404.
Time- and concentration-dependent biphasic effect of ochratoxin A on growth of proximal tubular cells in primary culture.
Gekle M, Pollock CA, Silbernagl S.
Department of Medicine, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, Australia.
Ochratoxin A (OTA) leads to trophic and functional changes in the proximal tubule of the kidney. We investigated the effects of micromolar and nanomolar concentrations of OTA on cell growth, cell viability and transepithelial transport in rat proximal tubular cells in primary culture. Micromolar concentrations of OTA exerted a hypotrophic and hypoplastic effect after 24 hr, but a hypertrophic and hypoplastic effect after 72 hr. These effects could be abolished in a concentration-dependent manner by the addition of albumin to the medium. In parallel, micromolar concentrations reduced cell viability, monolayer integrity and abolished the formation of transepithelial gradients of Na+ and K+. Nanomolar concentrations of OTA had neither hypotrophic nor hypertrophic effects, but stimulated DNA synthesis and cell division, leading to hyperplasia. At the same time, nanomolar concentrations did not reduce cell viability or the formation of electrolyte gradients. Lowering extracellular pH to 6.8 abolished the effect of nanomolar concentrations of OTA on DNA synthesis and cell number as well as the effect of micromolar concentrations on cellular protein. Cellular alkalinization (pH 7.7) also stimulated proliferation, but did not act additively with nanomolar concentrations of OTA. From these results, we conclude that OTA exerts a time-dependent biphasic effect on cellular protein content and a concentration-dependent biphasic effect on DNA synthesis. The stimulatory effect is independent of its toxic action. Modulation of both effects by extracellular pH suggests that cellular pH-homeostasis may be involved in the action of OTA.
PMID: 7562577 [PubMed - indexed for MEDLINE]
113. Eur J Epidemiol. 1995 Apr;11(2):235-8.
Balkan endemic nephropathy: still a mysterious disease.
Bozić Z, Duancić V, Belicza M, Kraus O, Skljarov I.
Department of Urology, University Hospital of Zagreb, Medical Faculty Sestre milosrdnice, Croatia.
Comment in Eur J Epidemiol. 1996 Jun;12(3):323.
Balkan endemic nephropathy (BEN) is an acquired, environmental, polytopical disease of the entire urinary tract, with long latency. Tubulointerstitial chronic nephritis, urotheliomas of all localities, and renal cell carcinoma occur with a significantly higher frequency in the affected population. These represent only clinical manifestations of one unique nosological entity. BEN occurs in focuses. Within them, it agglomerates in households, without any evidence of hereditary background. Patients with various clinical manifestations of the disease can be simultaneously found within one single household. BEN appears equally among members of different ethnic groups. Its aetiology is not clear enough. There is no evidence of a causal relationship with silicon compounds, heavy metals and viruses. Much attention has been recently focused on research of the aetiological role of mycotoxins, mainly ochratoxin A. Toxic and carcinogenic agents of natural origin are commonly accepted as the major cause of BEN.
PMID: 7672083 [PubMed - indexed for MEDLINE]
114. Nat Toxins. 1995;3(3):129-37.
Induction of apoptosis by T-2 toxin and other natural toxins in HL-60 human promyelotic leukemia cells.
Ueno Y, Umemori K, Niimi E, Tanuma S, Nagata S, Sugamata M, Ihara T, Sekijima M, Kawai K, Ueno I, et al.
Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
Based on the DNA fragmentation profile in gel electrophoresis and the morphological changes in electron microscopy, the induction of apoptotic nuclear changes by mycotoxins and other microbial products, in total 31 chemicals, was investigated in HL-60 human promyelotic leukemia cells, along with the cytotoxicity tests with 3-[4,5-dimethylthiazol-zyl]-2,5-diphenyltetrazolium bromide (MTT) and trypan blue exclusion. Among the chemicals tested, trichothecenes (T-2 toxin, roridin A, nivalenol, deoxynivalenol), certain anthraquinones (luteoskyrin, skyrin, 2-hydroxyemodin), diketopiperazines (emethallicin A, emestrin), isocoumarins (ochratoxin A, citrinin), lactone (penicillic acid), dihydrobisfuran (aflatoxin B1), potassium ionophore (valinomycin), and an inhibitor of interleukin-2 synthesis (cyclosporin A) were positive for the induction of DNA fragmentation. No DNA fragmentation was observed under the present conditions with fumonisin B1, cyclic peptides (cyclochlorotine, phalloidin, microcystin-LR), certain anthraquinones (emodin, chrysophanol, rugulosin), and others (sterigmatocystin, cytochalasin A, griseofulvin, fusaric acid, kojic acid, rubratoxin B, butenolide, wortmannin, FK506, and sphingosine). The apoptotic changes in the cells exposed to T-2 toxin and luteoskyrin were confirmed by electron microscopic observation. Detailed experiments on dose and time dependencies revealed that T-2 toxin induced the apoptosis at 10 ng/ml (= 4 x 10(-8) M) levels within 2-6 hr without significant cytotoxicity evaluated by the dye exclusion and MTT.
PMID: 7648021 [PubMed - indexed for MEDLINE]
115. Jpn J Ophthalmol. 1995;39(1):20-9.
Histological and histochemical studies of the normal and faulty closure of the embryonic fissure in the eye of ICR mouse.
Ikeda K, Shirai S, Majima A, Hirabayashi Y, Yamada K.
Department of Ophthalmology, Nagoya City University Medical School, Japan.
Histological and histochemical studies were carried out in Jcl:ICR mice to determine the changes in microscopic structures and glycosaminoglycan molecular species in the tissues involved in normal or faulty closure of the embryonic fissure. The purpose of this study was to elucidate the mechanism underlying the faulty closure of the embryonic fissure and to identify the key substances involved in normal and faulty closure. To obtain mice with an appropriate faulty closure of the embryonic fissure, ochratoxin A was employed as a teratogenic agent. Serial sections from tissues undergoing normal and faulty closure of the embryonic fissure were cut at a right angle to the fissure. As the staining procedures, a hematoxylin-eosin procedure and a sensitized high iron diamine method were used. A chemical modification (nitrous acid treatment) or an enzyme digestion procedure (chondroitinase ABC digestion procedure) was employed in combination with the sensitized high iron diamine method to identify the glycosaminoglycan molecular species in the tissues. The results obtained in the present study have substantiated the histophysiological importance of glycosaminoglycan molecular species during the course of histogenesis in the normal and the faulty closure of the embryonic fissure of developing murine eyes.
PMID: 7643479 [PubMed - indexed for MEDLINE]
116. Nephrol Dial Transplant. 1994;9 Suppl 4:116-20.
Inhaled mycotoxins lead to acute renal failure.
Di Paolo N, Guarnieri A, Garosi G, Sacchi G, Mangiarotti AM, Di Paolo M.
Nephrology and Dialysis Unit, USL 30, Siena Regional Hospital, Italy.
Mysterious deaths of archeologists after opening Egyptian tombs have been suspected, but never proved, to be secondary to inhalation of mycotoxin. We observed a case of acute renal failure (ARF) due to inhalation of ochratoxin A produced by a mould of the species Aspergillus ochraceus. After working 8 h in a granary closed for several months, a farmer and his wife suffered respiratory distress; the woman developed non-oliguric ARF and biopsy revealed tubulonecrosis. A strain of Aspergillus ochraceus producing ochratoxin was isolated from the wheat.
PMID: 7800243 [PubMed - indexed for MEDLINE]
117. Nat Toxins. 1994;2(6):366-70.
Ochratoxin A in human serum samples collected in southern Italy from healthy individuals and individuals suffering from different kidney disorders.
Breitholtz-Emanuelsson A, Minervini F, Hult K, Visconti A.
Consiglio Nazionale delle Ricerche, Istituto Tossine e Micotossine da Parassiti Vegetali, Bari, Italy.
Ochratoxin A was determined in human serum samples, collected in the south of Italy in November 1992, using ion-pair liquid chromatography and fluorescence detection. The samples were collected from healthy people (65 subjects) as well as from people with different kidney disorders. Five different kinds of kidney disorders were represented: transplanted subjects (13), chronic glomerulonephritis (8), renal calculus or cyst (6), chronic renal failure (13), and subjects treated by dialysis (28). The mean and median concentrations of ochratoxin A in the healthy group was 0.53 and 0.44 ng/ml serum, respectively. The highest mean concentration was found in the group of patients treated by dialysis, 1.4 ng/ml serum. A higher incidence of samples containing > 0.44 ng ochratoxin A/ml serum was found in the dialysis group, compared to the other groups. Comparing the mean concentrations by Student's t-test, a significant difference was found between the mean concentrations of the healthy group and of the group of patients treated by dialysis (P < 0.01). No other significant differences were found when comparing the groups two at a time.
PMID: 7704450 [PubMed - indexed for MEDLINE]
118. Arch Inst Pasteur Tunis. 1994 Jan-Apr;71(1-2):21-31.
[Ochratoxin A genotoxicity, relation to renal tumors].
[Article in French]
Maaroufi K, Pfohl-Leszkowicz A, Achour A, el May M, Grosse Y, Hammami M, Ellouz F, Creppy EE, Bacha H.
Laboratoire de Biochimie et de Toxicologie Moléculaire, Faculté de Médecine Dentaire, Monastir.
Ochratoxin A (OTA) is a mycotoxin which has been implicated in Balkan Endemic Nephropathy (BEN), a disease characterized by tubulonephritis and may be involved in the high incidence of urinary tract tumors associated to BEN. The prevalence of human ochratoxicosis is being determined in Tunisia. 100% of people suffering from chronic interstitial nephropathy of unknown etiology were ochratoxin A positive. These nephropathies are similar to Balkan Endemic Nephropathy. We prove an OTA genotoxic effects in patient suffering from this kind of nephropathy. OTA-DNA adducts formation has been detected in DNA of kidney tissues (biopsy). DNA adducts which are covalent complex between OTA and DNA base (Guanine), constitute first steps of the carcinogenesis process.
PMID: 7661650 [PubMed - indexed for MEDLINE]
119. Am J Med Genet. 1993 Nov 1;47(6):862-71.
Pathogenesis of craniofacial and body wall malformations induced by ochratoxin A in mice.
Wei X, Sulik KK.
University of North Carolina Birth Defects Center, Chapel Hill 27599-7090.
Ochratoxin A (OA), a mycotoxin commonly found in soils and on moldy food such as cereal grains, is a potent teratogen. The present investigation was designed to examine the teratogenicity of OA administered acutely at early post-implantation stages in mice, with particular emphasis on the pathogenetic basis of induced malformations. Maternal OA administration on gestational day (GD) 7 or 8 resulted in excessive amounts of cell death in selected cell populations. After a single dose of 2-4 mg/kg, excessive cell death was notable within 6 hours, and persisted to 36 hours post-treatment. As observed in GD 14 or 18 fetuses, the spectrum of induced craniofacial malformations included exencephaly, midfacial clefting, cleft lip, as well as hypotelorism, and synophthalmia associated with holoprosencephaly. Body wall defects involved either the abdominal wall alone, or in combination with the thoracic wall, resulting in partial or complete exposure of the viscera. Potential mechanisms for OA-induced selective cell killing are discussed.
PMID: 8279484 [PubMed - indexed for MEDLINE]
120. Nephron. 1993;64(4):621-5.
Acute renal failure from inhalation of mycotoxins.
Di Paolo N, Guarnieri A, Loi F, Sacchi G, Mangiarotti AM, Di Paolo M.
Nephrology and Dialysis Department, Regional Hospital of Siena, Italy.
Mysterious deaths of archeologists after opening Egyptian tombs have been suspected to be secondary to inhalation of mycotoxin, however, the hypothesis has never been verified. Recently, we observed a case of acute renal failure (ARF) undeniably due to inhalation of ochratoxin of Aspergillus ochraceus. After spending 8 h in a granary which had been closed for several months, a farmer and his wife suffered temporary respiratory distress; 24 h later, the woman developed nonoliguric ARF and biopsy revealed tubulonecrosis which healed in 24 days. Toxic substances were not found, but a strain of A. ochraceus producing ochratoxin was isolated from the wheat.
PMID: 8366990 [PubMed - indexed for MEDLINE]
121. Neurotoxicol Teratol. 1992 May-Jun;14(3):191-6.
Development of neurons and synapses in ochratoxin A-induced microcephalic mice: a quantitative assessment of somatosensory cortex.
Fukui Y, Hayasaka S, Itoh M, Takeuchi Y.
Department of Anatomy, Kagawa Medical School, Japan.
Ochratoxin A (a mycotoxin) is known to cause cell death in the developing brain of embryos 1-2 days after treatment. Microcephaly was observed with high frequency in mice by prenatal treatment with ochratoxin A. Using a stereological method, the numerical densities of neurons and synapses were investigated in the somatosensory cortex of 6-week-old microcephalic mice. The numerical density of neurons in ochratoxin A-treated mice represented a 39% increase compared to the control mice, but there was no difference in the numerical density of synapses. The somatosensory cortices of control mice had about 13,000 synapses per neuron, whereas ochratoxin A-treated mice had about 9,400 synapses per neuron. The deficits in synapse-to-neuron ratios seen in ochratoxin A-induced microcephalic brain seemed to result from a reduced dendritic growth.
PMID: 1635540 [PubMed - indexed for MEDLINE]
122. Toxicol Pathol. 1992;20(2):236-45.
Renal lesions induced by ochratoxin A exposure in the F344 rat.
Boorman GA, McDonald MR, Imoto S, Persing R.
National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Groups of 80 male and female F344 rats were exposed by gavage to ochratoxin A, a naturally occurring mycotoxin, at levels of 21, 70, and 210 micrograms/kg body weight for up to 2 years. Ochratoxin A induced non-neoplastic renal tubular epithelial changes consisting of cytoplasmic alteration, karyomegaly, degeneration, and cysts. Exposure-related renal tubular proliferative lesions included focal hyperplasia, tubular cell adenoma, and tubular cell carcinoma. Renal tubular cell adenoma occurred as early as 9 months in 1 high-dose male rat, and both adenomas and carcinomas were seen in males by 15 months. At the terminal sacrifice, renal tubular cell tumors were found in both male and female rats, but the response was more pronounced in the males. The incidence of renal tumors in the high-dose rats was the highest of any National Toxicology Program (NTP) study completed to date. In the high-dose males approximately one-third of the renal carcinomas developed metastases. This study demonstrates that ochratoxin A is a potent renal carcinogen in the F344 rat and suggests that contamination of feedstuff by this mycotoxin may pose a potential hazard to domestic animals and man.
PMID: 1475584 [PubMed - indexed for MEDLINE]
123. Proc Biol Sci. 1991 Dec 23;246(1317):251-9.
Persistent karyomegaly caused by Penicillium nephrotoxins in the rat.
Mantle PG, McHugh KM, Adatia R, Gray T, Turner DR.
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, U.K.
Continuous or intermittent consumption by rats of food moulded by Penicillium aurantiogriseum induced prominent and extensive histopathological changes within several weeks seen specifically at the renal cortico-medullary junction. Many cells of the P3 segment of proximal tubules contained either giant nuclei or multiple enlarged nuclei, described in this text as karyomegaly, but also included within a cytomegalic change. The changes contrasted with the tubular cell necrosis and concomitant mitosis elicited after only four days consumption of nephrotoxic mould. Unilateral nephrectomy enabled persistence of histopathological changes to be assessed directly after detailed histology at an earlier stage. After ten days consumption of food with a 100-fold excess of fungal extract containing the amphoteric nephrotoxins, the typical acute histopathology evolved, over a period of three weeks on normal diet, into the bizarre karyomegalic histopathology, implying a latent effect. Karyomegaly persisted for at least twelve months after nephrotoxin dosage ceased. P. aurantiogriseum karyomegaly was much more striking than that induced by a relatively high chronic dose of another Penicillium nephrotoxin, ochratoxin A. Although the study does not attempt to measure relative potencies, qualitatively similar ultrastructural changes (enlarged nuclei, proliferation of smooth endoplasmic reticulum and thickening of proximal tubule basement membranes) were induced by the two types of nephrotoxin. The broadly toxic ochratoxin A is the popular putative aetiological agent in the mysterious and insidious Balkan endemic nephropathy and associated urinary tract tumours. As the renal carcinogenicity of ochratoxin A in rats follows karyomegaly, the striking karyomegaly induced by P. aurantiogriseum in the proximal tubules of the kidney must be considered as a potential factor in human chronic renal disease.
PMID: 1686091 [PubMed - indexed for MEDLINE]
124. Nihon Ganka Gakkai Zasshi. 1991 Dec;95(12):1206-37.
[Developmental mechanisms of congenital eye abnormalities].
[Article in Japanese]
Department of Ophthalmology, Nagoya City University Medical School.
Experimental teratology in mice was studied to clarify the developmental mechanisms of congenital eye abnormalities. Pregnant Jcl: ICR mice were treated intraperitoneally with ochratoxin A on day 7 of pregnancy. The offspring were grossly observed on day 9, 10, 11, 12, 13, 14, 16 or 18 of gestation, or at the second or fourth week after birth. Then, the eyes were histologically examined in serial sections. Mother mice were injected with ochratoxin A on day 8, 9, 10 or 11 of pregnancy, and the eyes of fetuses were examined on day 16 of gestation to determine the critical periods for the congenital eye abnormalities. Pregnant C57BL/6NJcl mice were also given an intraperitoneal injection of ochratoxin A on day 7 of pregnancy, and the eyes of offspring were observed grossly and histologically on day 16 or 18 of gestation, or at the second or fourth week after birth. Fetal and postnatal eyes showed various kinds and degrees of developmental abnormalities histologically. They included anophthalmia, microphthalmia, aphakia, mesenchymal dysgenesis of the anterior segment, faulty separation of the lens vesicle, developmental abnormalities of the vitreous, faulty closure of the embryonic fissure, retinal rosette formation and aberrant optic nerve fiber. Since anophthalmia, microphthalmia and aphakia caused by the developmental disturbances of the optic and lens vesicles were not established in the fetuses whose mothers were treated with ochratoxin A after day 9 of pregnancy, the critical periods for these abnormalities were considered to be on day 8 of gestation or earlier. Mesenchymal dysgenesis of the anterior segment, faulty separation of the lens vesicle and developmental abnormalities of the vitreous were frequently observed in the fetuses whose mothers were injected with ochratoxin A on day 7, 8 or 9 of pregnancy. It was considered that there was a correlation between the critical periods for these three abnormalities and the stage of the neural crest cell migration around the optic vesicle. Mesenchymal dysgenesis of the anterior segment observed in mice corresponded to the Axenfeld-Rieger syndrome or Peters' anomaly encountered clinically. Processes of production of these abnormalities based on the faulty migration of the neural crest cells which form the ocular anterior segment were demonstrated.(ABSTRACT TRUNCATED AT 400 WORDS)
PMID: 1776602 [PubMed - indexed for MEDLINE]
125. IARC Sci Publ. 1991;(115):49-56.
Porcine nephropathy in Europe.
Department of Veterinary Microbiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
Numerous surveys conducted in North America, Asia and Europe have revealed that ochratoxin A is a natural contaminant of plant products. Contamination frequencies of up to 40% have been encountered, at levels in the range of 5-500 micrograms/kg. Ochratoxin A is a major causal determinant of the disease porcine nephropathy; but other nephrotoxic mycotoxins, such as citrinin and the fungal quinones, may be involved. The disease is characterized clinically by polyuria and growth depression. Renal lesions in pigs include degeneration of the proximal tubules, interstitial fibrosis and hyalinization of the glomeruli. The disease is endemic, outbreaks being associated with bad weather conditions. A positive correlation has been observed between the prevalence rates of porcine nephropathy and the frequency of ochratoxin A in corresponding feed samples. Surveys for residues of ochratoxin A in kidneys from cases of porcine nephropathy in a number of European countries other than Denmark have demonstrated that 21-42% of samples contain ochratoxin A in the range of 1-100 micrograms/kg.
PMID: 1820353 [PubMed - indexed for MEDLINE]
126. IARC Sci Publ. 1991;(115):267-72.
Chromosomal alterations in lymphocytes of patients with Balkan endemic nephropathy and of healthy individuals after incubation in vitro with ochratoxin A.
Manolov G, Manolova Y, Castegnaro M, Chernozemsky IN.
National Centre of Oncology, Sofia, Bulgaria.
The possible involvement of mycotoxins in chromosomal alterations in patients with Balkan endemic nephropathy (BEN) was investigated cytogenetically. Lymphocyte cultures from patients with BEN and from individuals from a nonendemic region were examined and compared with cultures from healthy people which had been incubated in vitro with noncytotoxic doses of ochratoxin A. Significantly increased numbers of various numerical and structural anomalies were found in patients with BEN. Chromosome X in female patients occurred in both monosomic and polysomic forms. A 'prosomization' effect was seen along the entire length of supernumerary X chromosomes, manifested by retarded contraction resembling early mitotic stages, with a comparably detailed band pattern. No other specific numerical or structural change was found consistently in BEN patients. Incubation of the lymphocytes of healthy people with ochratoxin A induced similar aberrations and prosomization. These findings may support the hypothesis that ochratoxin A is involved in the pathogenesis of BEN.
PMID: 1820341 [PubMed - indexed for MEDLINE]
127. IARC Sci Publ. 1991;(115):229-44.
Carcinogenicity of ochratoxin A in experimental animals.
National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.
The carcinogenicity of ochratoxin A, a naturally occurring mycotoxin of the fungal genera Aspergillus and Penicillium, was evaluated in three strains of mice and in one strain of rats. The kidney, and in particular the tubular epithelial cells, was the major target organ for ochratoxin A-induced lesions. In male ddY and DDD mice, atypical hyperplasia, cystadenomas and carcinomas of the renal tubular cells were induced, as were neoplastic nodules and hepatocyte tumours of the liver. In B6C3F1 mice, tubular-cell adenomas and carcinomas of the kidneys were induced in male mice, and the incidences of hepatocellular adenomas and carcinomas were increased in male and female mice. In male and female F344 rats, ochratoxin A induced nonneoplastic (degeneration, karyomegaly, proliferation, cytoplasmic alteration, hyperplasia) and neoplastic effects (adenomas, and carcinomas with metastases) in the kidneys; the incidence of fibroadenomas of the mammary glands was also increased in female rats. Other studies on ochratoxin A were considered inadequate for evaluating the presence or absence of a carcinogenic effect; however, these are mentioned and referenced below. The collective experimental findings, together with accumulating evidence in humans, forecast further toxic and carcinogenic effects in humans exposed to ochratoxin A, mainly via foodstuffs.
PMID: 1820337 [PubMed - indexed for MEDLINE]
128. IARC Sci Publ. 1991;(115):215-27.
A molecular basis for target-cell toxicity and upper urothelial carcinoma in analgesic abusers and patients with Balkan endemic nephropathy.
School of Science, Polytechnic of East London, United Kingdom.
Ochratoxin A is ubiquitous in regions where Balkan endemic nephropathy is common. It damages the kidney cortex in a range of experimental animals and induces renal parenchymal carcinoma in mice, but it is not a potent carcinogen, nor is there experimental evidence to link it to upper urothelial carcinoma (UUC). A model UUC can be induced experimentally in rodents by urothelial initiation, followed by an acutely induced papillary necrosis. This two-stage experimental model may help to clarify the role of ochratoxin A in initiating or promoting upper urothelial cells and increase our understanding of the development of UUC in patients with Balkan endemic nephropathy.
PMID: 1820336 [PubMed - indexed for MEDLINE]
129. IARC Sci Publ. 1991;(115):171-86.
Mechanism of action of ochratoxin A.
Dirheimer G, Creppy EE.
Institut de Biologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Strasbourg, France.
Ochratoxin A has a number of toxic effects in mammals, the most notable of which is nephrotoxicity. It is also immunosuppressive, teratogenic and carcinogenic. The biochemical and molecular aspects of its action were first studied in bacteria. The appearance of 'magic spots' (ppGpp and pppGpp) pointed to inhibition of the charging of transfer ribonucleic acids (tRNA) with amino acids. This suggestion was confirmed by the demonstration that ochratoxin A inhibits bacterial, yeast and liver phenylalanyl-tRNA synthetases. The inhibition is competitive to phenylalanine and is reversed by an excess of this amino acid. As a consequence, protein synthesis is inhibited, as shown with hepatoma cells in culture, with Madin Darby canine kidney cells (which are much more sensitive) and in vivo in mouse liver, kidney and spleen, the inhibition being more effective in the latter two organs. An excess of phenylalanine also prevents inhibition of protein synthesis in cell cultures and in vivo. Analogues of ochratoxin A in which phenylalanine has been replaced by other amino acids have similar inhibitory effects on the respective amino acid-specific aminoacyl tRNA synthetases. 4R-Hydroxyochratoxin A, a metabolite of ochratoxin A, has a similar action, whereas ochratoxin alpha (the dihydroisocoumarin moiety) and ochratoxin B (ochratoxin A without chlorine) have no effect. Ochratoxin A might act on other enzymes that use phenylalanine as a substrate. We showed recently that it inhibits phenylalanine hydroxylase. In addition, the phenylalanine moiety of ochratoxin A is partially hydroxylated to tyrosine by incubation with hepatocytes and in vivo. This competitive action with phenylalanine might explain why this amino acid prevents the immuno-suppressive effect of ochratoxin A and partially prevents its teratogenic and nephrotoxic actions. The effect of ochratoxin A on protein synthesis is followed by an inhibition of RNA synthesis, which might affect proteins with a high turnover. Ochratoxin A also lowers the level of phosphoenolpyruvate carboxykinase, a key enzyme in gluconeogenesis; this inhibition is reported to be due to a specific degradation of mRNA that codes for this enzyme. Recently, ochratoxin A was also found to enhance lipid peroxidation both in vitro and in vivo. This inhibition might have an important effect on cell or mitochondrial membranes and be responsible for the effects on mitochondria that have been shown by several authors. Finally, the recent results of Pfohl-Leszkowicz et al. (this volume), who showed the formation of DNA adducts mainly in kidney but also in liver and spleen, explain the DNA single-strand breaks observed previously in mice and rats after acute and chronic treatment.
PMID: 1820332 [PubMed - indexed for MEDLINE]
130. IARC Sci Publ. 1991;(115):119-27.
Penicillium aurantiogriseum-induced, persistent renal histopathological changes in rats; an experimental model for Balkan endemic nephropathy competitive with ochratoxin A.
Mantle PG, McHugh KM, Adatia R, Heaton JM, Gray T, Turner DR.
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, United Kingdom.
Renal histopathological changes in rats, caused by food partially moulded by a common fungus isolated from an area of nephropathy in Yugoslavia, were differentiated into acute and chronic responses. The acute response to a few days on the diet specifically involved necrosis and concomitant mitosis in proximal tubule cells. More protracted, continuous or intermittent administration of nephrotoxic mould led to a marked karyomegaly in the same corticomedullary region. The phenomenon is more prominent than that induced by treatment with ochratoxin A over a similar period, raising the question of the putative role of such mycotoxins in the etiology of chronic human renal disease.
PMID: 1820324 [PubMed - indexed for MEDLINE]
131. J Environ Pathol Toxicol Oncol. 1990 Jan-Apr;10(1-2):56-63.
The mode of action of ochratoxin A in acute enteritis in rats.
Kanisawa M, Suzuki S, Moroi K.
Department of Pathology, Yokohama City University School of Medicine, Japan.
The mode of action of ochratoxin A(OCT A) was studied in male Wistar rats in connection with the development of acute enteritis. Acute enteritis in the duodenum and jejunum identical with that induced by oral administration was also induced by parenteral application at the dose level of 15 mg/kg OCT A and was completely inhibited by ligation of the choledochus. Direct application of OCT A into the jejunal blind sac lumen constructed by two ligations induced severe inflammation in situ and also revealed remote action to the duodenum and jejunum where separated from the blind sac by ligation. This remote action was inhibited by ligation of the choledochus. These results clearly demonstrated the enterohepatic circulation of OCT A. The ileal injection also revealed remote action of OCT A, although no pathologic change was caused in the ileal mucosa. The results obtained suggest that the enteritis may be induced by direct exposure of OCT A to the intestinal mucosa without metabolic activation, although certain participation of ochratoxin alpha to accelerate the inflammation was suspected.
PMID: 2231315 [PubMed - indexed for MEDLINE]
132. Ophthalmic Paediatr Genet. 1989 Mar;10(1):33-46.
Experimental models of anterior segment dysgenesis.
Department of Cell Biology and Anatomy, School of Medicine, University of North Carolina, Chapel Hill 27599.
Normal anterior segment embryogenesis is summarized followed by a review of syndromes of spontaneous and inherited conditions of abnormal development in humans and animals. The study of teratogen-induced malformations in animal models has provided valuable information about critical periods during gestation for the initiation of anterior segment dysgenesis. Although the major developmental events leading to iridocorneal angle formation occur during the third trimester, it appears that embryonic insult much earlier in human gestation (during the first three to five weeks post fertilization) can induce an abnormal sequence of events leading to anterior segment dysgenesis.
PMID: 2662095 [PubMed - indexed for MEDLINE]
133. Toxicology. 1988 Dec 16;53(1):57-67.
Residual hematopoietic effect in mice exposed to ochratoxin A prior to irradiation.
Hong HH, Jameson CW, Boorman GA.
Chemical Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
Erratum in Toxicology 1989 Feb;54(2):227.
Ochratoxin A (OCT A) has the potential to cause myelotoxicity in addition to the well-known toxic effects on the liver and kidney. Whereas in previous studies the bone marrow parameters were examined shortly after injection, experiments reported here were designed to determine whether mice would recover from the myelotoxic effects induced to OCT A injection and secondly whether mice previously injected to OCT A would be more sensitive to radiation-induced myelotoxicity than vehicle controls. Six-week old female B6C3F1 mice were injected intraperitoneally on alternate days over a week with a total dose of 20 or 40 mg/kg of OCT A and bone marrow parameters monitored for up to 16 weeks. Controls received vehicle alone. There was a suppression of marrow granulocyte macrophage progenitors (CFU-C) in OCT A-treated animals which returned to normal values by 2 weeks (20 mg/kg group) or by 5 weeks (40 mg/kg group) following the last treatment. Some of the OCT A-treated mice were additionally irradiated with 200 rads of whole body irradiation (WBI) at 10 and 52 days following OCT A injections. Irradiation caused a significant reduction in CFU-Cs in all mice but the effects were more pronounced in the mice that had received OCT A previously. The bone marrow parameters of 40 mg/kg OCT A-treated mice returned to normal by 6 weeks after first WBI. A second WBI produced similar depression in CFU-Cs with again a delayed 8 weeks recovery as compared to controls in both dose groups of OCT A-treated mice. The delayed recovery in bone marrow progenitors was also reflected in lower peripheral white blood counts after the second irradiation in 40 mg/kg OCT A-treated mice as compared to the untreated irradiated controls. This indicated that residual bone marrow effect of OCT A makes the mice more sensitive to subsequent irradiation induced injury.
PMID: 3059580 [PubMed - indexed for MEDLINE]
134. Vet Pathol. 1987 Sep;24(5):427-35.
Histopathologic and electron microscopic studies on the acute toxicity of ochratoxin A in rats.
Albassam MA, Yong SI, Bhatnagar R, Sharma AK, Prior MG.
Animal Sciences Wing, Alberta Environmental Centre, Vegreville, Canada.
Ochratoxin A was given by gavage to male rats. Moribund and dead animals were necropsied, and the surviving rats, including the controls, were killed 48 hours after dosing. Many of the principal rats were moribund, or began dying, within 12 to 24 hours after dosing. Lesions suggestive of disseminated intravascular coagulation were seen by light microscopy as early as 12 hours after dosing; fibrin deposits were in the spleen, brain choroid plexus, glomerular capillaries, liver, and heart. Renal tubular nephrosis, hepatic and lymphoid necrosis, and necrotic enteritis with villous atrophy were also seen. Electron microscopy demonstrated fibrin strands mixed with degranulated platelets, necrotic leukocytes, and swollen endothelial cells in glomerular capillaries. Myocardial changes included focal supercontracted sarcomeres adjacent to intercalated disks. Swollen sarcolemma, lysed myofibrils and fragmented Z-bands with interstitial edema, vascular thrombosis, and endothelial damage were also seen. The acute pathologic changes induced by ochratoxin A in the intestine, liver, and lymphoid tissues were more obvious than the tubular nephrosis, and the development of a disseminated intravascular coagulation-like syndrome with myocardial changes was a complicating factor.
PMID: 3672808 [PubMed - indexed for MEDLINE]
135. J Environ Sci Health B. 1987 Aug;22(4):455-70.
Protective effects of sodium bicarbonate on murine ochratoxicosis.
Yong S, Albassam M, Prior M.
Animal Sciences Wing, Alberta Environmental Centre, Canada.
The protective effect of sodium bicarbonate (NaHCO3), a urine modifier, to alleviate murine ochratoxicosis was investigated. The study included two trials. Urinary pH was altered before oral administration of ochratoxin A (OA) in Trial 1, and animals were given combined doses of OA and ethyl biscoumacetate (Eb) in Trial 2. Acute toxicity of OA as measured by LD50 values was reduced by 23% and 20% in rats treated with NaHCO3 for Trials 1 and 2 respectively. Bicarbonate-treated rats dosed with 20 mg/kg OA or with a combination dose of OA at 17 mg/kg and Eb at 50 mg/kg, had a lower frequency of histological lesions in kidneys, liver, lung, spleen and heart. Two types of heart lesions found in the present study are described.
PMID: 2821093 [PubMed - indexed for MEDLINE]
136. J Am Vet Med Assoc. 1986 Jun 15;188(12):1399-402.
Ochratoxicosis in Iowa swine.
Cook WO, Osweiler GD, Anderson TD, Richard JL.
Ochratoxicosis was diagnosed in 2 Iowa swine herds. In both cases, clinical signs consisted of increased urination and water consumption. Pale tan kidneys were found in affected pigs at necropsy. Histologic examination of renal tissue from an affected pig revealed diffuse tubular nephrosis and interstitial fibrosis. In both cases, ochratoxin A was detected by thin-layer chromatography in extracts of whole corn and ground complete feed. Ochratoxicosis was reproduced in swine with feed obtained in one of the cases.
PMID: 3744966 [PubMed - indexed for MEDLINE]
137. J Natl Cancer Inst. 1985 Oct;75(4):733-42.
Ochratoxin A carcinogenesis in the (C57BL/6J X C3H)F1 mouse.
Bendele AM, Carlton WW, Krogh P, Lillehoj EB.
The potential carcinogenic effects of the mycotoxin ochratoxin A [(OA); CAS: 303-47-9] were assessed in a 24-month feeding study in male and female (C57BL/6J X C3H)F1 (B6C3F1) mice. The mice were assigned to 3 groups of 50 males and 50 females each; group 1 mice were the controls, group 2 mice were fed 1 ppm OA, and group 3 mice were fed 40 ppm OA. Renal neoplasms, both carcinomas and adenomas, were found only in male mice of the 40-ppm dose group. Fourteen of 49 animals that survived at least 20 months had neoplasms morphologically consistent with renal carcinoma. Renal adenomas were present in some of these mice and in other 40-ppm-group males, making a total of 26 mice with renal adenomas. All male mice of the 40-ppm dose group had nephropathy characterized by varying degrees of renal tubular dilation, attenuation and hyperplasia of lining epithelium, and proliferation of regenerative tubules. Females of the 40-ppm dose group had similar but less severe renal changes but no carcinomas or adenomas. Compound-related renal lesions were absent in the 1-ppm dose group. The incidence of hepatocellular neoplasms was slightly increased in male and female mice fed diets containing OA. These results indicate that OA is a renal carcinogen in male B6C3F1 mice and a hepatic carcinogen in female mice of this strain.
PMID: 3862905 [PubMed - indexed for MEDLINE]
138. Toxicon. 1985;23(2):247-54.
Ochratoxin A-induced porcine nephropathy: enzyme and ultrastructure changes after short-term exposure.
Elling F, Nielsen JP, Lillehøj EB, Thomassen MS, Størmer FC.
Four pigs were treated with ochratoxin A (800 micrograms/kg) for five consecutive days. Subsequently, urine and bile were collected and kidneys were perfusion fixed unilaterally. Liver and kidney samples were examined for the distribution of ochratoxin A and metabolites in subcellular fractions and the effects of the toxin on protein synthesis and enzyme activities. Ochratoxin A and the hydrolytic product, ochratoxin alpha, were found in urine. Elevated levels of toxin accumulation in kidney (283 ng/g) compared with liver (189 ng/g) and toxin-mediated reductions in protein synthesis and enzyme activities in kidney identified it as a target organ of ochratoxin toxicity. Ultrastructural investigations of kidney in toxin-exposed animals identified a process of condensation of cellular material with disappearance of membranes and continuous desquamation in the lower part of the proximal convoluted tubules. In target cells peroxisomes appeared to have lost membrane integrity and the organelles were leaking materials into the cytosol. Reduction of structural integrity was associated with an increase in the presence of catalase and cyanide insensitive fatty acid oxidase activity in the soluble kidney fractions.
PMID: 4024134 [PubMed - indexed for MEDLINE]
139. C R Seances Soc Biol Fil. 1985;179(5):688-95.
[DNA damage in the spleen, liver and kidneys of mice treated with ochratoxin A].
[Article in French]
Creppy EE, Kane A, Dirheimer G, Lafarge-Frayssinet C, Mousset S, Frayssinet C.
Ochratoxin A a natural contaminant of feed and food has been shown to induce experimental liver and kidney tumors. Since there is a good correlation between the carcinogenic potency of chemicals and the DNA damages induced in mammalian cells treated either in vivo or in vitro by these compounds, we have measured single-strand breaks induced by ochratoxin A in DNA of liver, spleen and kidney. Our data clearly showed that ochratoxin A induced DNA damages in vitro as well as in vivo. Damages were dose-dependent, reversible and vary upon the time according to the tissue. In spite there is no report up to now on experimental leukemia induced by ochratoxin A, our results indicate that this possibility have to be considered.
PMID: 2938698 [PubMed - indexed for MEDLINE]
140. Gan No Rinsho. 1984 Sep;30(12 Suppl):1445-56.
[Pathogenesis of human cancer development due to environmental factors].
[Article in Japanese]
In spite of a remarkable progress of the experimental research on carcinogenesis, no clear-cut elucidation has been made on pathogenesis of human cancer. Carcinogenesis due to environmental factors may be characterized by the diversity in causal agents, the lower level in the exposure density and the very random exposure chance to the agents. These characteristics are largely different from those employed in the ordinary animal experiment. Therefore, simple deduction from the experimentally obtained knowledges may lead to incorrect understanding of the developmental steps in human cancer. An instance clearly showed this is differences in the morphological features observed between the human and the animal tissues in which the former often shows a single and de novo development but the latter exhibits various precancerous lesions and multicentric development. In human, repeated exposures to carcinogens are primarily essential to induce cancer in the usual conditions, and the more possible way of carcinogenesis would be the synergistic and/or cocarcinogenic process including initiation-promotion steps. These problems were discussed by using the author's own evidences obtained from animal model experiments.
PMID: 6096589 [PubMed - indexed for MEDLINE]
141. Berl Munch Tierarztl Wochenschr. 1984 Aug 1;97(8):279-83.
[Determination and occurrence of ochratoxin A in slaughtered swine].
[Article in German]
Bauer J, Gareis M, Gedek B.
PMID: 6487256 [PubMed - indexed for MEDLINE]
142. Aust Vet J. 1984 Jul;61(7):219-22.
Experimental ochratoxicosis A in pigs.
Tapia MO, Seawright AA.
Ochratoxin A was isolated from a culture of Aspergillus ochraceus grown on a cornmeal substrate. The mycotoxin was added to a grower ration for 14 kg young pigs at 2, 4, 8 and 16 mg/kg and fed to groups of 3 for periods ranging from 6 to 20 days. The highest dose rate group only became sick, with loss of appetite, weight loss, polydipsia, polyuria, proteinuria, glucosuria, elevation of serum creatinine, pale swollen kidneys, renal tubular degeneration and cortical fibrosis. The pigs on the 2 mg toxin/kg of diet appeared unaffected with only slight renal tubular degeneration present in one animal. Feeding diet contaminated with the intermediate doses of 4 and 8 mg toxin/kg diet lead to reduction of weight gain and/or reduced feed intake and feed conversion efficiency as well as mild renal lesions. Ochratoxin A has recently been reported on mould-affected grain in Queensland and some local strains of A. ochraceus in culture have been shown to be able to produce levels of ochratoxin A of up to 4000 mg/kg of substrate. Rare episodes of nephrotoxicity in pigs seen at slaughter in Queensland may thus be due to prior contamination of the diet with ochratoxin A.
PMID: 6497807 [PubMed - indexed for MEDLINE]
143. Appl Environ Microbiol. 1984 May;47(5):1118-25.
Toxic effects of fermented and unfermented sorghum meal diets naturally contaminated with mycotoxins.
Kazanas N, Ely RW, Fields ML, Erdman JW Jr.
Male weanling rats fed diets containing fermented and unfermented tannin-free sorghum meals naturally contaminated with traces of ochratoxin A, zearalenone, and an unidentified toxic substance developed anorexia. Mean changes in body weight over a 28-day feeding period for rats fed fermented and unfermented sorghum meal and ANCR casein diets of 8% protein were -2.8, +13.8, and +100.5 g, respectively. Rats fed fermented sorghum meal developed alopecia; hematological findings showed a decreased mean corpuscular volume, hypochromic microcytosis, balanced leukopenia, and hypoproteinuria . Histological findings showed testicular hypoplasia of the germinal epithelium and no mature spermatozoa. Necrosis and mineralization in Henle's loop were also observed. No damage was apparent to the liver, cerebellum, cerebrum, spleen, or adrenal glands.
PMCID: PMC240074 PMID: 6234860 [PubMed - indexed for MEDLINE]
144. J Toxicol Environ Health. 1984;14(4):535-50.
Effects of ochratoxin A in the partially nephrectomized rat.
Stein AF, Geerling S, Mollenhauer HH, Kubena LF, Heidelbaugh ND, Phillips TD.
The effects of ochratoxin A (OA), a nephrotoxic mycotoxin, were investigated in partially nephrectomized (PN) rats (approximately 70% reduction in renal mass) following compensatory hypertrophy of the renal remnant. Renal function stabilized 27 d after surgery. PN rats compensated for the initial loss of renal function except for glomerular filtration rate (GFR, inulin clearance); this remained significantly impaired. Sham-operated (SO) rats cleared inulin and p-aminohippurate (PAH) at rates of 3.84 and 7.49 ml/min, respectively, while compensated PN rats cleared inulin at 2.51 and PAH at 8.84 ml/min. Daily administration of low levels of OA produced decreased urine osmolality and body weight with a modest increase in urinary protein of PN versus SO rats. OA-treated rats cleared inulin, creatinine, and PAH at rates significantly lower than nontreated controls: 0.89 and 1.96 ml/min for inulin, 0.35 and 0.56 ml/min for creatinine, and 2.29 and 6.23 ml/min for PAH. Histopathological findings indicated a considerable increase in renal tubular necrosis and subcellular damage (i.e., loss of cytoplasmic ground substance, vacuolization, degeneration of mitochondria, and reorganization of endoplasmic reticulum) in PN animals versus controls, concurrent with alteration in renal function. These results verify that the nephrotoxic action of OA is elicited mainly in renal proximal tubules and is enhanced in the PN rat.
PMID: 6512881 [PubMed - indexed for MEDLINE]
145. Cancer Lett. 1982 Jul-Aug;16(2):137-43.
Quantitative analysis of initiating and promoting activities of five mycotoxins in liver carcinogenesis in rats.
Imaida K, Hirose M, Ogiso T, Kurata Y, Ito N.
The initiating and promoting activities of several mycotoxins were investigated in F344 male rats. N-2-Fluorenylacetamide (2-FAA) was used as an initiator or a promoter and citrinin, ochratoxin A, sterigmatocystin, (+)rugulosin or patulin was administered at a fixed dose for the same period in the initiation stage or the promotion stage. Partial hepatectomy and administration of carbon tetrachloride (CCl4) were examined to increase the induction of hyperplastic nodules. Ochratoxin A, sterigmatocystin and (+)rugulosin administered in either the initiating or the promoting stage significantly increased the induction of hyperplastic nodules. Citrinin and patulin administered in the initiating stage significantly increased the induction of hyperplastic nodules, but were not effective when administered during the promoting stage. The theoretical classification of the mycotoxins examined is discussed.
PMID: 7127276 [PubMed - indexed for MEDLINE]
146. J Environ Sci Health B. 1981;16(5 Pt B):557-73.
Ochratoxin A and penicillic acid interaction in mice.
Shepherd EC, Phillips TD, Joiner GN, Kubena LF, Heidelbaugh ND.
Penicillic Acid (PA) and Ochratoxin A (OA) are toxic fungal metabolites that are synergistic in combination. This interaction was investigated using mice which were doses orally as follows: control, none; solvent control, 0.2 ml bicarbonate buffer; PA, 40 mg/kg; OA, 10 mg/kg and combination, 40 mg/kg PA + 10 mg/kg OA. The only significant histopathologic change observed was an acute multifocal toxic tubular nephrosis which appeared most severe in the combination-treated mice killed on day 10. While the combination group had a death rate of 20% (5/25), no deaths occurred in the other treatment groups. The increased death rate and the extensive nephrotoxic findings in the combination group indicate a toxic interaction between OA and PA at sublethal dose levels and is consistent with a renal site of action.
PMID: 7299071 [PubMed - indexed for MEDLINE]
147. Toxicol Appl Pharmacol. 1981 Jan;57(1):127-37.
Brain necrosis in mouse fetuses transplacentally exposed to the mycotoxin ochratoxin A.
Szczech GM, Hood RD.
PMID: 7209983 [PubMed - indexed for MEDLINE]
148. Food Cosmet Toxicol. 1979 Aug;17(4):406-8.
The kidney and ochratoxin A.
PMID: 520974 [PubMed - indexed for MEDLINE]
149. Experientia. 1979 Jul 15;35(7):890-2.
Effects of low doses of ochratoxin A after intratesticular injection in the rat.
Moré J, Camguilhem R.
The toxic effect of various doses of ochratoxin A on the rat testis was investigated after a single intratesticular injection. At time of sacrifice (day 10) degenerating changes occur in the testicular tissues: seminiferous tubules dilatation, cytolysis of the seminiferous epithelium, hyperplasia of the interstitial tissue, vascular thrombosis. The relations between the blood supply disturbances and the observed lesions are discussed.
PMID: 477844 [PubMed - indexed for MEDLINE]
150. Acta Pathol Microbiol Scand A. 1979 Jul;87A(4):237-43.
Ochratoxin A-induced mycotoxic porcine nephropathy: alterations in enzyme activity in tubular cells.
Mycotoxic porcine nephropathy was induced by p.o. administration of crystalline ochratoxin A for periods of 5 days, 3 months and 2 years. Enzyme activities of the renal tissue were studied histochemically. These were NADH-tetrazolium reductase, NADPH-tetrazolium reductase, lactate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, alpha-glycerophosphate dehydrogenase, unspecific acid phosphatase and unspecific alkaline phosphatase. The activity of NADH-tetrazolium reductase and succinate dehydrogenase was reduced in the proximal tubule of all nephrons after 5 days ochratoxin A exposure and remained reduced after 3 months and 2 years exposure. The effect of ochratoxin A on these enzymes would appear to cause the impairment of proximal tubular function and the morphological changes observed in the proximal tubule in ochratoxin A-induced mycotoxic porcine nephropathy. The localization of alterations in enzyme activity corresponds to the localization of ochratoxin A previously demonstrated in the kidney. The activities of NADPH-tetrazolium reductase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and unspecific alkaline phosphatase were reduced focally corresponding to the areas with focal tubular atrophy and the degree of reduction was roughly parallel to the degree of atrophy.
PMID: 474126 [PubMed - indexed for MEDLINE]
151. Vet Pathol. 1979 Jul;16(4):466-75.
Porcine nephropathy induced by long-term ingestion of ochratoxin A.
Krogh P, Elling F, Friis C, Hald B, Larsen AE, Lillehøj EB, Madsen A, Mortensen HP, Rasmussen F, Ravnskov U.
Nine pigs were fed crystalline ochratoxin A in their feed at a concentration of about 1 mg/kg. Three pigs and their controls were killed after 3 months and 6 pigs and controls were killed after 2 years. A decrease of the ratio TmPAH/CIn, increased urinary glucose excretion and decreased ability to concentrate urine, occurred within a few weeks and aggravated slightly during the 2-year period. Changes in renal structure, characterized by degeneration and atrophy of proximal tubules, interstitial fibrosis and hyalinization of glomeruli, were progressive during time of exposure, but terminal renal failure was not reached. The kidney, liver, muscular and adipose tissue contained 3 to 27 microgram ochratoxin A/kg after 3 months of exposure. No further accumulation of ochratoxin A residue was found after 2 years of exposure.
PMID: 452321 [PubMed - indexed for MEDLINE]
152. Toxicol Appl Pharmacol. 1977 Oct;42(1):55-64.
Histopathological studies on the toxicity of ochratoxin A in rats. I. Acute oral toxicity.
Kanisawa M, Suzuki S, Kozuka Y, Yamazaki M.
PMID: 929607 [PubMed - indexed for MEDLINE]
153. Food Cosmet Toxicol. 1977 Oct;15(5):411-8.
Mycotoxic diseases produced in mice by species of the Aspergillus ochraceus group.
Zimmermann JL, Carlton WW, Tuite J, Fennell DI.
PMID: 598791 [PubMed - indexed for MEDLINE]
154. Vet Pathol. 1977 Jul;14(4):392-406.
Ochratoxin A and citrinin induced nephrosis in Beagle dogs. III. Terminal renal ultrastructural alterations.
Kitchen DN, Carlton WW, Hinsman EJ.
The extent and type of renal ultrastructural changes in Beagle dogs varied with the administration of ochratoxin A and citrinin alone and in the two dosage combinations. The three predominant changes were cytoplasmic vacuolation, myelin figure formation and lesions designated as cytoplasmic disarray. These changes were mainly of the endomembane system of the tubular epithelial cells. Cytoplasmic vacuoles were within proximal and distal tubules and collecting ducts and were most numerous in dogs given 10 mg/kg critrinin. Vacuolation of similar distribution, but less severe, was seen in renal tubular cells of dogs given the higher dose of the combined mycotoxins (0.2 mg/kg ochratoxin A + 10 mg/kg citrinin). This damage was limited to the proximal tubular cells in dogs given only ochratoxin A (0.1 or 0.2 mg/kg). Myelin figures were in proximal epithelial cells of dogs given ochratoxin A alone or combined with citrinin. There was cytoplasmic disarray in dogs of all groups except for dogs given 5 mg/kg citrinin. This lesions was usually limited to the proximal tubules. The lesions, however, was found in cells of the distal tubules of dogs given 10 mg/kg citrinin alone.
PMID: 560743 [PubMed - indexed for MEDLINE]
155. Vet Pathol. 1977 May;14(3):261-72.
Ochratoxin A and citrinin induced nephrosis in Beagle dogs. II. Pathology.
Kitchen DN, Carlton WW, Tuite J.
Beagle dogs were given ochratoxin A (0.1 and 0.2 mg/kg) and citrinin (5 and 10 mg/kg) alone and in two dose combinations for 14 days. The gross lesions included focal peritonitis and intestinal intussusceptions in dogs given citrinin. Changes in the kidneys of dogs given ochratoxin A were degeneration and necrosis with desquamation of tubular epithelial cells, primarily in the straight segment of the proximal tubules. Dogs given 10 mg/kg citrin had similar changes in the distal tubules and collecting ducts. Dogs given combined doses of citrinin and ochratoxin A had degeneration and necrosis in proximal and distal tubules, and in thin segments and the collecting ducts; there were desquamated cells and granular casts in the lumina. Dogs given ochratoxin A had necrosis of lymphoid tissues in the spleen, tonsil, thymus, peripheral lymph nodes and lymph nodules of the ileum, colon and rectum. There was ulceration of the mucosa of the intestine in dogs given large combined doses of ochratoxin A and citrinin.
PMID: 883089 [PubMed - indexed for MEDLINE]
156. Acta Pathol Microbiol Scand A. 1977 Mar;85A(2):151-6.
Demonstration of ochratoxin A in kidneys of pigs and rats by immunofluorescence microscopy.
Ochratoxin A was localized in the kidney of pigs and rats by means of immunofluorescence microscopy after short-time exposure. Antibody against ochratoxin A was obtained from rabbits after repeated injections of bovine serum albumin-ochratoxin A conjugate. Ochratoxin A was localized exclusively in the proximal tubule. Light microscopically, necrosis and desquamation of epithelial cells in the pig kidneys were restricted to the proximal tubule where the toxin was found. The investigation had demonstrated conclusively that the proximal tubule is the target part of the nephron in ochratoxin A-induced mycotoxic nephropathy.
PMID: 66854 [PubMed - indexed for MEDLINE]
157. Folia Haematol Int Mag Klin Morphol Blutforsch. 1977;104(6):810-5.
[Effect of ocrase on thrombin induced DIC in rats].
[Article in German]
PMID: 75151 [PubMed - indexed for MEDLINE]
158. Acta Pathol Microbiol Scand A. 1976 Sep;84(5):429-34.
Experimental porcine nephropathy: changes of renal function and structure perorally induced by crystalline ochratoxin A.
Krogh P, Elling F, Gyrd-Hansen N, Hald B, Larsen AE, Lillehoj EB, Madsen A, Mortensen HP, Ravnskov U.
Nine pigs were fed crystalline ochratoxin A in amounts corresponding to a feed level of 1 mg per kg for 3 months. The only observable lesion developed was a kidney damage, identical to the naturally occurring porcine nephropathy. The changes of renal function was characterized by impairment of proximal tubular function, indicated by a decrease of the ratio TmPAH/CIn, of the ability to concentrate urine, and by an increased urinary excretion of glucose. The decrease of the ratio TmPAH/CIn is correlated with time of exposure to ochratoxin A. The changes of renal structure were characterized by degeneration of the proximal tubules, leading to tubular atrophy accompanied by interstitial fibrosis. At the end of the experiment the kidney, liver, adipose and muscular tissue of the slaughtered pigs contained sizable amounts of ochratoxin A residues. As the pigs would have passed the meat inspection this represents a possible health problem. The changes observed in this study are identical to those observed by feeding to pigs grains naturally contaminated with ochratoxin A.
PMID: 970130 [PubMed - indexed for MEDLINE]
159. Toxicology. 1976 Aug-Sep;6(2):235-42.
Time-dependent disappearance of ochratoxin A residues in tissues of bacon pigs.
Krogh P, Elling F, Hald B, Larsen AE, Lillehoj EB, Madsen A, Mortensen HP.
Crystalline ochratoxin A was administered to bacon pigs for one month. After termination of toxin exposure the pigs were slaughtered at different intervals and analyses for ochratoxin A residues in four tissues were conducted. Kidneys contained the highest concentrations, and fat the lowest, at each interval. Ochratoxin A disappeared from muscles and fat after 2 weeks, from liver after 3 weeks, and from the kidneys after 4 weeks. The toxin disappeared from tissues exponentially. All the pigs would have passed the meat inspection because no pathologic lesions were developed although tissues contained mycotoxin residues. The results of this study indicate that contamination of meat by ochratoxin A may be avoided by feeding pigs ochratoxin-free feed during the last 4 weeks before slaughter.
PMID: 968918 [PubMed - indexed for MEDLINE]
160. Proc Annu Meet U S Anim Health Assoc. 1976;(80):130-48.
Experimental mycotoxicoses in calves with aflatoxin, ochratoxin, rubratoxin, and T-2 toxin.
Pier AC, Cysewski SJ, Richard JL, Baetz AL, Mitchell L.
PMID: 1078072 [PubMed - indexed for MEDLINE]
161. Adv Vet Sci Comp Med. 1976;20:147-70.
PMID: 795285 [PubMed - indexed for MEDLINE]
162. Toxicol Appl Pharmacol. 1975 Dec;34(3):479-90.
Studies on the nephrotoxicity of ochratoxin A in rats.
Suzuki S, Kozuka Y, Satoh T, Yamazaki M.
PMID: 1209641 [PubMed - indexed for MEDLINE]
163. Ann Rech Vet. 1975;6(2):207-18.
[Aspergillus ochraceus Wilhelm toxins. IV. — Toxicity in rat by prolonged oral administration of ochratoxin A (author's transl)].
[Article in French]
Galtier P, Bodin G, Moré J.
Adult male and female rats are given oral doses of 0.25 to 8 mg/kg of ochratoxin A daily for 10 days. This study confirms the intoxication symptomatology and weight loss observed in rat and mouse after sole administration of toxins. Estimation of the DL C50 and the calculation of the detoxication coefficient show accumulation of ochratoxin A in the organism. Microscopic lesions emphasize ochratoxin A aggression on hepatocytes, nephrocytes and megacaryocytes. Serious renal failure may cause the appearance of digestive ulcerating lesions; their association to eventual coagulation factor deficiency, related to toxic action on liver or blood platelets, may be at the origin of the hemorrhagic syndrome observed.
PMID: 1163963 [PubMed - indexed for MEDLINE]
164. Vet Pathol. 1974;11(5):385-406.
Ochratoxicosis in Beagle dogs. III. Terminal renal ultrastructural alterations.
Szczech GM, Carlton WW, Hinsman EJ.
PMID: 4462257 [PubMed - indexed for MEDLINE]
165. J Am Vet Med Assoc. 1973 Dec 1;163(11):1295-7.
Penicillium viridicatum toxins and mold nephrosis.
Carlton WW, Tuite J, Caldwell R.
PMID: 4593859 [PubMed - indexed for MEDLINE]
166. J Am Vet Med Assoc. 1973 Dec 1;163(11):1269-73.
Ochratoxin A--occurrence and toxicity.
Munro C, Scott PM, Moodie CA, Willes RF.
PMID: 4586755 [PubMed - indexed for MEDLINE]
167. Vet Pathol. 1973;10(4):347-64.
Ochratoxin A toxicosis in swine.
Szczech GM, Carlton WW, Tuite J, Caldwell R.
PMID: 4788582 [PubMed - indexed for MEDLINE]
168. Vet Pathol. 1973;10(3):219-31.
Ochratoxicosis in Beagle dogs. II. Pathology.
Szczech GM, Carlton WW, Tuite J.
PMID: 4779121 [PubMed - indexed for MEDLINE]
169. Bull World Health Organ. 1973;49(4):411-8.
Mycotoxic nephropathy in pigs.
Elling F, Moller T.
In Denmark a nephropathy in pigs characterized by tubular atrophy and interstitial fibrosis has been identified frequently during the last 5 decades in the course of meat inspection in slaughterhouses. The disease was first described by Larsen, who recognized the connexion between feeding mouldy rye to pigs and the development of the nephropathy. In this study kidneys were examined from 19 pigs coming from a farm with an outbreak of nephropathy. The barley fed to the pigs was contaminated with the mycotoxin ochratoxin A. Histological examination revealed different degrees of change ranging from slight regressive changes in the tubular epithelium and periglomerular and interstitial fibrosis to tubular atrophy, thickened basement membranes, glomerular sclerosis, and marked fibrosis. These differences were considered to be due to differences in the length of time of exposure to the mouldy barley and differences in the amount of mycotoxin consumed by the individual pig. However, it will be necessary to carry out experiments using crystalline ochratoxin A in order to prove such a relationship. Mycotoxins have also been suggested as etiological factors in Balkan nephropathy in man, which in the initial stages is characterized by tubular lesions similar to those seen in mycotoxic nephropathy in pigs.
PMCID: PMC2480949 PMID: 4546872 [PubMed - indexed for MEDLINE]
170. Toxicol Appl Pharmacol. 1972 Jan;21(1):130-42.
Mycotoxicosis induced in mice by Penicillium ochraceum.
Carlton WW, Tuite J, Caldwell RW.
PMID: 5022330 [PubMed - indexed for MEDLINE]
171. Toxicol Appl Pharmacol. 1971 Nov;20(3):4239-41.
Toxicity and excretion of ochratoxin A in rats intubated with pure ochratoxin A or fed cultures of Penicillium viridicatum.
Van Walbeek W, Moodie CA, Scott PM, Harwig J, Grice HC.
PMID: 5132783 [PubMed - indexed for MEDLINE]
172. J Pathol Bacteriol. 1966 Apr;91(2):521-9.
Acute liver injury in ducklings and rats as a result of ochratoxin poisoning.
Theron JJ, van der Merwe KJ, Liebenberg N, Joubert HJ, Nel W.
PMID: 5918625 [PubMed - indexed for MEDLINE]