Allantoin as a Marker of Oxidative Stress: Inter- and Intraindividual Variability in Urinary Concentrations in Healthy Individuals

Abstract

Altered systemic oxidative stress is a consequence of environmental exposures and diseases, among other stress factors. The extent of oxidative stress in humans is assessed through the analysis of oxidative stress biomarkers (OSBs) in biospecimens such as urine. Allantoin is an OSB, a specific product of the oxidation of uric acid, that is measurable in urine. In this study, concentrations and inter- and intraindividual variability in urinary concentrations of allantoin were determined in healthy individuals. The results were compared with those found for other OSBs of lipids, proteins, and DNA in the same set of samples. Allantoin was found in all urine samples (N = 515), at concentrations that ranged from 0.88 to 41.7 mmol mol–1 creatinine (0.90 to 112 μg mL–1 urine). The intraclass correlation coefficient (ICC) of urinary allantoin measured in samples collected longitudinally for over a month from 19 individuals (0.74 for creatinine corrected and 0.80 for volumetric concentrations) showed an excellent ...