Senescent cells drive aging inflammation, but measuring it remains hard
As we age, certain cells accumulate that can no longer divide. Rather than staying quiet, these cells continuously release inflammatory signals that damage surrounding tissue. The problem: scientists still lack reliable ways to measure this in living humans.
That is the central message of a comprehensive review published in Biomedicines. The authors describe how two processes, cellular senescence and chronic low-grade inflammation (known as inflammaging), amplify each other during aging. Each is damaging on its own. Together, they contribute to conditions such as cardiovascular disease, dementia, and type 2 diabetes.
A cell that stops dividing but keeps signaling
A senescent cell halts its own replication but remains metabolically active, secreting a cocktail of pro-inflammatory molecules called the SASP (senescence-associated secretory phenotype). These molecules can damage neighboring cells and sustain local inflammation. In animal models, clearing senescent cells has repeatedly improved disease outcomes and extended healthy lifespan. In humans, however, a crucial link is missing.
The researchers highlight the absence of robust biomarkers: measurable signals in blood or tissue that reliably indicate how many senescent cells a person carries and how much damage they cause. Without such measurements, regulators cannot easily determine whether a treatment is engaging its intended target.
The bottleneck for new therapies
This directly affects the future of so-called senolytics: drugs that selectively eliminate senescent cells. Several candidates are already in testing, but regulators require biomarkers demonstrating that a drug actually reaches and clears the right cells. Those biomarkers do not yet exist. This practical obstacle is slowing the translation of laboratory findings into clinical treatments.
The review also stresses the bidirectional nature of the problem: inflammation accelerates senescence, and senescence intensifies inflammation. This makes it difficult to determine which process comes first in any individual patient. The authors tentatively identify senescence as the more measurable and therefore more actionable entry point for further research.
From a longevity perspective, this is a meaningful gap. Until measurement improves, the true scale of senescent cells’ contribution to human aging remains unclear. Better biomarkers, the authors argue, will be what eventually closes that gap.
Search terms for further reading: senescence biomarkers aging, SASP inflammaging mechanisms, senolytics clinical translation