Role of ochratoxin in disease causation

Area of Science:

• Veterinary toxicology
• Nephrology
• Animal pathology

Background:

• Alimentary exposure to ochratoxin A induces renal damage in various animal species, including pigs.
• Ochratoxin A-induced nephropathy (MPN) is an endemic disease in pigs, particularly in Europe, linked to climatic conditions affecting harvests.
• Ochratoxin A is a known renal carcinogen in mice, though not observed in female pigs after 2-year exposure.

Purpose of the Study:

• To investigate the structural and functional changes in pig kidneys due to ochratoxin A exposure.
• To identify sensitive biomarkers for early detection of ochratoxin A-induced nephropathy, given the rapid metabolism and excretion of the toxin.
• To evaluate the diagnostic utility of renal tubular enzyme activity in assessing ochratoxin A exposure.

Main Methods:

• Experimental induction of renal damage in pigs via controlled alimentary ochratoxin A exposure.
• Morphological assessment of renal tissues, including proximal tubule atrophy, interstitial fibrosis, and glomerular changes.
• Functional evaluation of kidney impairment, measuring tubular reabsorption capacity (TmPAH/Cin) and urine concentrating ability.
• Analysis of renal biopsy samples for the activity of phosphoenolpyruvate carboxykinase and gamma-glutamyl transpeptidase.

Main Results:

• Ochratoxin A exposure caused dose-dependent renal damage, including tubular atrophy, fibrosis, and glomerular sclerosis.
• Functional impairment was evidenced by decreased TmPAH/Cin and reduced urine concentrating ability.
• Reduced activity of renal tubular enzymes, phosphoenolpyruvate carboxykinase and gamma-glutamyl transpeptidase, was observed following short-term ochratoxin A exposure.
• A 40% reduction in enzyme activity was noted after just one week of exposure, correlating with the severity of renal impairment.

Conclusions:

• Ochratoxin A is a significant nephrotoxin in pigs, causing characteristic structural and functional renal alterations.
• Rapid metabolism of ochratoxin A limits the utility of tissue analysis for retrospective exposure assessment.
• Analysis of renal tubular enzyme activity in biopsy samples provides a sensitive and reliable method for detecting early-stage ochratoxin A-induced nephropathy in pigs.