A Pilot MicroRNA Aging Clock
Researchers here build an aging clock based on the expression levels of three microRNAs as a proof of principle that microRNA clocks are viable. This should not be a surprise; if the past twenty years of work on aging clocks have taught us anything, it is that any sufficiently complex body of data that changes with age can be used as the basis for a clock. Clocks are now relatively easily produced. The much harder challenge is to take any given clock and amass sufficient human data to (a) demonstrate that it is usefully measuring biological age or something closely related to biological age, and (b) understand its quirks and limitations to the point at which one can trust the use of that clock in the assessment of potential rejuvenation therapies, in order to guide and accelerate progress in the field.
The extension of human longevity has intensified the search for biomarkers that capture not only chronological age but also biological aging and functional healthspan. Among molecular candidates, microRNAs (miRNAs) have emerged as promising regulators and indicators of aging-related processes. In this pilot study, we explored whether selected circulating miRNAs could serve as potential biomarkers of biological age and lifestyle-associated aging dynamics.
Based on current literature, we focused on three miRNAs - miR-24, miR-21, and miR-155 - previously linked to inflammation, senescence, and metabolic regulation. Capillary blood samples from a heterogeneous adult cohort were analyzed using quantitative PCR. Values were integrated into a composite "miRNA-3Age" model through multivariate regression analysis to estimate biological age. Associations between lifestyle variables (diet, exercise, stress, and smoking) and miRNA-based biological age were examined.
The miRNA-3Age model predicted biological age with moderate correlation to chronological age and revealed variability consistent with individual health profiles. Participants with favorable lifestyle factors (e.g., frequent consumption of fish, whole grains, and green tea; regular exercise) tended to exhibit lower miRNA-3Age estimates, whereas stress and smoking were associated with higher predicted biological age. The miRNA-3Age model provides a preliminary step toward a scalable, lifestyle-sensitive aging metric that warrants validation in diverse populations.