Molecular aging occurs differently in people — Live Science
People of the same chronological age may experience significantly different molecular changes in the body as they age. This conclusion was reached by researchers who tracked gene activity and metabolite levels in the blood of 335 women aged 32 to 80 over eight years, Live Science reports.
Observations over eight years
The participants belonged to the TwinsUK cohort, which includes identical and fraternal twins. Each woman visited the clinic at least three times between 2009 and 2017, while the median interval between the first and last visits was six years. During the visits, scientists collected blood samples and measured gene activity and concentrations of metabolites — small molecules formed during the body's chemical reactions.
The researchers analyzed more than 16,000 genes and 915 metabolites. Of these, 5,061 genes and 181 metabolites underwent statistically significant changes over time. For 5,036 genes and 45 metabolites, the group showed a common trend toward increasing or decreasing levels. Many genes were associated with pathways related to immune system function, metabolism, heart disease, and neurodegenerative disorders.
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Different trajectories of change
At the same time, average trends did not reflect all individual variations. Study co-author Kerrin Small, a professor of genomics at King's College London, noted that in some people, gene activity or metabolite levels changed in the opposite direction from that seen in most participants. Differences between participants were identified for 136 metabolites: a substance whose level rose in one woman could decline in another or remain almost unchanged.
The researchers suggested that genetics, environmental influences, and circadian biological rhythms may explain some of these differences. Identical twins had more similar patterns of gene expression than fraternal twins, indicating a significant role of heredity. Different types of immune cells also showed distinct patterns of gene activity with age. About one-quarter of genes and metabolites showed seasonal fluctuations, while up to 40% of metabolites depended on circadian biological rhythm.
Study limitations
The authors also recorded declining blood levels of PFAS, including PFOA and PFOS. They suggested this could be linked to restrictions on the use of these synthetic substances in the United Kingdom, but the study did not prove a causal link between PFAS and changes in genes or metabolites. The work was observational, included only women, and was based solely on blood analysis, so larger and more diverse studies are needed to verify the findings.
