The search for accurate ways to measure biological age is an ongoing quest in aging research. It is important for academia to reach a consensus on robust, cost-effective, and reliable biomarkers of aging in order for the field to progress. Currently, there is a lack of reliable and fast ways to assess biological age and thus determine the outcome of potential interventions that target the aging processes.
Lifespan studies are, generally speaking, the most reliable and widely accepted way to determine if an intervention works or not; obviously, this is costly and time-consuming, and something better is needed in order to speed up research progress. Currently, the gold standard for aging biomarkers is the epigenetic clock, which is based on changes to DNA methylation patterns, but we need more ways to measure aging.
MCP-1, a new biomarker
A new study published recently added another potential biomarker of aging to the mix. The researchers identified monocyte chemoattractant protein-1 (MCP-1) as a potential biomarker of biological age. MCP-1/CCL2 is an important chemokine that recruits monocytes, memory T cells, and dendritic cells to the sites of inflammation created by tissue injury or infection[2-3].
The research team noted that circulating MCP-1 increased in an age-dependent manner in wild-type mice. They also showed that circulating MCP-1 was increased in the two mouse models of progeria that were also included in the study. This makes sense, as the more damaged aged tissues become, the more the immune system is attracted to the site of inflammation; thus, MCP-1 increases with age.
Genetic and drug-based interventions that slow the aging of mice were also found to lower the levels of MCP-1 significantly. Finally, they also demonstrated that, in humans with aortic stenosis, MCP-1 levels were significantly higher in frail individuals compared to non-frail.
These findings suggest that MCP-1 could be a suitable candidate biomarker for biological aging, and the biomarker also shows a responsiveness to interventions that increase lifespan.
 Yousefzadeh, M. J., Schafer, M. J., Noren Hooten, N., Atkinson, E. J., Evans, M. K., Baker, D. J., … & Niedernhofer, L. J. (2017). Circulating levels of monocyte chemoattractant protein‐1 as a potential measure of biological age in mice and frailty in humans. Aging Cell.
 Carr, M. W., Roth, S. J., Luther, E. D., Rose, S. S., & Springer, T. A. (1994). Monocyte chemoattractant protein 1 acts as a T-lymphocyte chemoattractant. Proceedings of the National Academy of Sciences, 91(9), 3652-3656.
 Xu, L. L., Warren, M. K., Rose, W. L., Gong, W., & Wang, J. M. (1996). Human recombinant monocyte chemotactic protein and other CC chemokines bind and induce directional migration of dendritic cells in vitro. Journal of leukocyte biology, 60(3), 365-371.