Biomarkers for monitoring renal damage from occupational chromium exposure

Abstract

A descriptive literature review was conducted, focusing on analyzing the effects of occupational chromium exposure on renal function in exposed workers. Scientific articles published from 2016 onward were collected from recognized databases such as PubMed, Scopus, SciELO, Redalyc, and Web of Science. The results indicate that the most studied glomerular biomarkers were serum creatinine and estimated glomerular filtration rate (eGFR). Proximal tubular biomarkers included β2-microglobulin, retinol-binding protein (RBP), α1-microglobulin, N-acetyl-β-D-glucosaminidase (NAG), and kidney injury molecule-1 (KIM-1). Distal and mixed tubular biomarkers included albuminuria, total urinary protein, and neutrophil gelatinase-associated lipocalin (NGAL). Studies in tannery workers in Bangladesh, India, Pakistan, and Ethiopia demonstrated significant elevations in urinary KIM-1 (>24 times reference levels), total protein, and urinary chromium (2.89 ± 4.23 μg/g creatinine vs. <0.12 μg/g in the general population). A significant correlation was found between airborne chromium levels (0.05–15 mg/m³), urinary chromium, and biomarkers of tubular damage. The occupational reference values ​​established by the ACGIH for urinary hexavalent chromium are: an increase >9.9 μg/L between pre- and post-shift (daily exposure) and >24.9 μg/L at the end of the workweek (cumulative exposure). It was concluded that KIM-1, NAG, β2-microglobulin, and RBP are sensitive biomarkers for the early detection of proximal tubular damage caused by chromium. Albuminuria and serum creatinine detect more advanced damage. Occupational health surveillance programs need to be implemented that include periodic biological monitoring (urinary chromium) combined with biomarkers of renal effect (KIM-1, NAG) to prevent chronic nephropathy in workers exposed to chromium, especially in tanning industries.