Metabolomic approaches to the normal aging process

Aging is a multifaceted process involving the accumulation of diverse deleterious changes in biological systems over time, so significant alterations in cellular metabolism are detected throughout aging. In the present study, the metabolic processes relevant to the normal aging process were investigated via non-targeted metabolomics using liquid chromatography–mass spectrometry. To exclude physiological and environmental differences, the metabolic profiles and the relevant metabolic pathways were analyzed in plasma from two separate study groups comprising two distinctly aged cohorts of healthy individuals, the elderly and the younger. The first group was recruited from an urban hospital, and the second group was recruited from a rural community. Alterations in fatty acid beta-oxidation, glycerophospholipid metabolism, and sphingolipid metabolism were identified as significant metabolic pathways relevant to normal aging. It was also found that sphingosine in sphingolipid metabolism, long-chain acylcarnitines in beta-oxidation, and lysophosphatidylcholines (LysoPCs) in glycerophospholipid metabolism could be critical candidate metabolites in the aging process. These results suggest that the metabolic profile of the healthiest individuals could be associated with the normal function of mitochondria, the primary organelle of redox homeostasis, as indicated by their low acylcarnitine to l-carnitine ratio and low levels of LysoPCs and sphingosine in plasma. The present study provides a critical contribution to the entire picture of the aging process.