Ochratoxicosis A in young Khaki Campbell ducklings

Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans

Ochratoxin A (OTA) is a ubiquitous mycotoxin produced by fungi of improperly stored food products. OTA is nephrotoxic and is suspected of being the main etiological agent responsible for human Balkan endemic nephropathy (BEN) and associated urinary tract tumours. Striking similarities between OTA-induced porcine nephropathy in pigs and BEN in humans are observed. International Agency for Research on Cancer (IARC) has classified OTA as a possible human carcinogen (group 2B). Currently, the mode of carcinogenic action by OTA is unknown. OTA is genotoxic following oxidative metabolism. This activity is thought to play a central role in OTA-mediated carcinogenesis and may be divided into direct (covalent DNA adduction) and indirect (oxidative DNA damage) mechanisms of action. Evidence for a direct mode of genotoxicity has been derived from the sensitive 32P-postlabelling assay. OTA facilitates guanine-specific DNA adducts in vitro and in rat and pig kidney orally dosed, one adduct comigrates with a synthetic carbon (C)-bonded C8-dG OTA adduct standard. In this paper, our current understanding of OTA toxicity and carcinogenicity are reviewed. The available evidence suggests that OTA is a genotoxic carcinogen by induction of oxidative DNA lesions coupled with direct DNA adducts via quinone formation. This mechanism of action should be used to establish acceptable intake levels of OTA from human food sources.

Balkan endemic nephropathy and associated urinary tract tumours: a review on aetiological causes and the potential role of mycotoxins

A series of publications in the 1950s described a kidney disease in Bulgaria, the former Yugoslavia and Romania that became known as Balkan endemic nephropathy (BEN). The disease was qualified by World Health Organisation (WHO) experts as 'progressive and very gradually developing renal failure with insidious onset.... The last stage shows marked fibrosis...'. BEN is characterized by tubular degeneration, interstitial fibrosis and hyalinization of glomeruli accompanied by enzymuria and impaired renal function without nephrotic syndrome. Later, an association between BEN and tumours of the kidney pelvis and ureter was recognized, so that the problem of BEN became not only nephrological, but also oncological. There may also be an association with increased urinary bladder cancer incidence, although many confounding factors may interfere in the analysis of data for this organ. In view of the very intimate association between BEN and the urinary tract tumours (UTT), the term 'endemic uropathy' has been proposed. Several hypothesis concerning the aetiology of these diseases has been investigated, which include: predisposing genes factors, environmental factors (heavy metals, minerals, bacteria, leptospira, viruses, fungal toxins and, most recently, pliocene lignites). This paper reviews the different hypotheses about the aetiology of endemic uropathy and pays particular attention to the role of fungal toxins.