Urinary leucine aminopeptidase 3 in population environmentally exposed to airborne arsenic

Abstract

Introduction: Environmental arsenic contamination is a major toxicological problem worldwide due to its carcinogenic and nephrotoxic potential. Aim: The purpose of this observational study was to determine the suspected association between urinary arsenic (uAs) and urinary leucine (or leucyl) aminopeptidase 3 (uLAP3) to evaluate uLAP3 as a candidate biomarker of exposure to airborne arsenic. Materials and Methods: A total of 918 adults occupationally and/or environmentally exposed to airborne arsenic were enrolled in the study. Baseline information (age; sex; history of smoking; alcohol, fish and seafood consumption) was gathered. Total uAs concentrations [μg/L] of 918 subjects, as well as the sum of arsenic species (ΣiAs) in 259 subjects, were obtained. Urinary LAP3 was measured by an immune-enzymatic assay using an ELISA kit. Urinary creatinine concentration was assessed with the IB/lAB/1289 research protocol (version II, 2015-09-17). The values of uAs and uLAP3 were recalculated per unit of creatinine. The association between uAs and uLAP3 was assessed using a logistic regression model adjusted for confounders. Results: The study identified a positive correlation between the logarithm of uAs and the logarithm of uLAP3 in the study population (r = 0.1737, p < 0.0000) and between urinary creatinine and uLAP3 concentration not adjusted for creatinine level (r = 0.1871, p < 0.001). In the logistic regression model, there was also an association between increased (≥15 µg/L) uAs and decreased (below the 25th quartile) uLAP3 [OR uLAP3 = 1.22 (95% CI 1.03 to 1.44, p < 0.02)]. Conclusions: These data suggest that urinary LAP3 may be a potential biomarker of arsenic exposure, which warrants further study.