The Problem

Ochratoxin A (OTA)

Why is OTA important and what can it do?

Ochratoxin A is a known nephrotoxin, carcinogen, teratogen and is possibly also genotoxic. It has long been known that OTA is a potent nephrotoxin and renal carcinogen, with pigs showing great sensitivity. As a potent toxin it mainly affects the kidneys, where it can cause both acute and chronic lesions, and it has been implicated in the aetiology of Balkan Endemic Nephropathy, a lethal kidney disease of humans common in, but restricted to, several valleys in the Balkans. By contrast Ochratoxin B (the dechloro derivative of OTA) is non-toxic.

OTA's nephrotoxic effect has been demonstrated in all mammalian species. In acute toxicity studies, LD₅₀ values vary greatly in different species, the dog being especially susceptible. OTA is also a potent teratogen in mice, rats, hamsters and chickens. Both teratogenic and reproductive effects have been demonstrated, and it is known to affect the immune system in a number of mammalian species.

In the last ten years some work has indicated that its mode of carcinogenicity is 'genotoxic'. However, OTA's genotoxicity is not certain, and recent work funded by DG XII of the EU has demonstrated that DNA binding of OTA is not detectable with sensitive analytical methods, and is unlikely to represent a mechanism for OTA-induced tumor formation.¹

¹ See Mally A, Zepnik H, Wanek P, Eder E, Dingley K, Ihmels H, Volkel W, Dekant W. Ochratoxin A: lack of formation of covalent DNA adducts. Chem Res Toxicol. 2004 Feb; 17 (2): 234-42.