Urinary Biomarkers of Mycotoxin Induced Nephrotoxicity-Current Status and Expected Future Trends

Abstract

The intensifying world-wide spread of mycotoxigenic fungal species has increased the possibility of mycotoxin contamination in animal feed and the human food chain. Growing evidence shows the deleterious toxicological effects of mycotoxins from infants to adults, while large population-based screening programs are often missing to identify affected individuals. The kidney functions as the major excretory system, which makes it particularly vulnerable to nephrotoxic injury. However, few studies have attempted to screen for kidney injury biomarkers in large, mycotoxin-exposed populations. As a result, there is an urgent need to screen them with sensitive biomarkers for potential nephrotoxicity. Although a plethora of biomarkers have been tested to estimate the harmful effects of a wide spectrum of toxicants, β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are currently the dominant biomarkers employed routinely in environmental toxicology research. Nevertheless, kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as useful and informative markers to reveal mycotoxin induced nephrotoxicity. In this opinion article we consider the nephrotoxic effects of mycotoxins, the biomarkers available to detect and quantify the kidney injuries caused by them, and to recommend biomarkers to screen mycotoxin-exposed populations for renal damage.

Keywords: AKI; KIM-1; NAG; NGAL; biomarkers; citrinin; mycotoxin; nephrotoxicity; ochratoxin A.

Figure 1

Biomarkers used to assess renal damage on the different sections of the nephron. Several putative urinary biomarkers are shown. Some of them are under study while other are well established. Modified from [8].

Figure 2

Schematic representation of sensitivity of traditional and novel biomarkers of nephrotoxicity. Filtration Rate (red line), the amount of blood filtered through the glomerulus per minute, is the clinical measure renal function (blue line). Unfortunately, the most widely accepted indicators of filtration rate lack sensitivity. Novel biomarkers have the potential of detecting damage before it becomes irreversible. Modified from [8].