Aging markers in human urine: A comprehensive, non-targeted LC-MS study
Metabolites in human biofluids document individual physiological status. We conducted comprehensive, non-targeted, non-invasive metabolomic analysis of urine from 27 healthy human subjects, comprising 13 youths (30{+/-}3 yr) and 14 seniors (76{+/-}4 yr). Quantitative analysis of 99 metabolites revealed 55 that were linked to aging, displaying significant differences in abundance between the two groups. These include 13 standard amino acids, 5 methylated, 4 acetylated, and 9 other amino acids, 6 nucleosides, nucleobases, and derivatives, 4 sugar derivatives, 5 sugar phosphates, 4 carnitines, 2 hydroxybutyrates, 1 choline, and 1 ethanolamine derivative, and glutathione disulfide. Abundances of 53 compounds decreased, while 2 increased in elderly people. Many age-linked markers were highly correlated; 42 of 55 compounds, showed Pearsons correlation coefficients larger than 0.70. As metabolite profiles of urine and blood are quite different, age-related information in urine components offer yet more valuable insights into aging mechanisms of endocrine system and related organ systems.