Oxidative stress was measured by assessing urinary concentrations of F2-isoprostanes. Isoprostanes are prostaglandin-like compounds that are produced by free radical-mediated peroxidation of lipoproteins. 15-F2t-isoprostane (15-F2t-IsoP; formerly called 8-epi-PGF2α) is the best characterized isoprostane, and is widely regarded as the “gold standard” for oxidant status.
Sample Collection and Preparation
Subjects were instructed to collect a midstream urine sample from their first morning void on Quarantine Day 0. Urine specimens were diluted with Enhanced Dilution Buffer (1:6) to a final volume 100 μL prior to assay.
15-F2t-IsoP levels in urine were quantified using a competitive enzyme linked-immunosorbent assay (ELISA) as described in the manufacturer’s protocol (product No. EA85, Oxford Biomedical Research, Inc., Oxford, MI, USA). All assays were performed in duplicate.
Urinary 15-F2t-IsoP levels were adjusted by urinary creatinine (Crn) levels (see Creatinine). An index of oxidative stress (IsoP [ng]/Crn [mg]) was calculated. This index represents the net oxidative stress effect, taking into account one marker of oxidative stress and of antioxidant defenses.
Sasaki, D. M., Yuan, Y., Gikas, K., et al. (2002). Enzyme immunoassays for 15-F2T isoprostane-M, a urinary biomarker for oxidant stress. Advances in Experimental Medicine & Biology, 507, 537-41.