Serum phospholipids during aging: A comprehensive systematic review of cross-sectional and case-control studies.

Background: The lipidome, as a subset of metabolomics, can undergo significant variations due to several factors, including the aging process. Therefore, this study aims to summarize the relationship between aging and alterations in plasma phospholipids.

Methods: A comprehensive search was conducted in MEDLINE (PubMed), Scopus, Embase, Web of Science, and Google Scholar databases up to September 2023. The PRISMA guidelines were adhered to throughout all stages of the review process. Cross-sectional and case-control studies that investigated the relationship between aging and phosphatidylcholine (PC), lysophosphatidylcholine (LPC), sphingomyelins (SM), ceramides, phosphatidylethanolamines (PE), and phosphatidylinositol (PI) were included.

Results: A total of 8486 studies were identified, of which 32 met the predefined inclusion criteria. The systematic review included data from 70,499 participants. The findings revealed that four studies reported a positive association between PCs and aging in both sexes, while one study reported an inverse relationship. Additionally, two studies found that PCs were positively associated with aging in men and negatively associated in women. Furthermore, four studies indicated a negative association between PC metabolites and the aging process. With regard to LPCs, two studies demonstrated a positive correlation, and two studies showed an inverse correlation with aging in both sexes. For SMs, five studies reported a positive association, whereas two studies identified an inverse association with aging trends. Similarly, five studies reported a positive correlation between PE levels and aging, while two studies showed a negative correlation.

Conclusion: Phospholipids play a critical role in the aging process, aging-related diseases, and the regulation of lifespan. A reduction in the levels of PCs and LPCs has been identified as a characteristic feature of aging.