All Life (Dec 2024)
The reliability, sensitivity and specificity of fluorescent oxidation products for measuring global oxidative stress in vivo
Abstract
Introduction To examine the reliability, sensitivity, and specificity of fluorescent oxidation products (FlOPs; markers of global oxidative damage) for measuring global oxidative stress. Methods To improve FlOP measurement reliability, we mixed plasma samples with the extractant at eight ratios and measured FlOPs with a fluorescent microplate reader (excitation/emission wavelengths 320/420 nm denoted FlOP_320; 360/420 nm [FlOP_360]; and 400/475 nm [FlOP_400]). In a human study, we examined the reliability of an improved FlOP measurement. In an animal study, we examined the sensitivity and specificity of FlOPs for measuring D-galactose induced global oxidative stress. Results At a 1:20 (plasma/extractant) mixture ratio, the overall inter-/intra-assay coefficients of variation (CV) for FlOP measurements among healthy and coronary heart disease participants were <3.6%/<2.7% and <4.4%/<2.0%, respectively. On day 30 of the animal experiment, the Pearson correlations (r) of FlOP_320 and FlOP_360 with D-galactose dose were 0.816 and 0.801, respectively, which were 3-12 times higher than those of malondialdehyde (0.183), 8-hydroxyguanosine (0.157), pentosidine (0.254), and nitrotyrosine (0.068) for measuring D-galactose-induced oxidative damage. FlOP_360 (r = 0.225, P = 0.045), but not FlOP_320 and FlOP_400, were significantly correlated with c-reactive protein, a marker of inflammation. Conclusions FlOP_320 are reliable, sensitive and specific markers for measuring global oxidative stress. Key policy highlights Fluorescent oxidation products (FlOPs) are a reliable marker of oxidative stress FlOPs at 320/420 nm are more sensitive than traditional markers FlOP at 320/420 nm did not reflect inflammation as quantified by c-reactive protein
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