Blood test maps senescent cells tissue by tissue

Senescent cells are cells that stop dividing but do not die. They secrete a mix of pro-inflammatory substances that damage surrounding tissues. This combination of secreted substances is called the SASP (secretory associated senescence phenotype). As we age, senescent cells accumulate in almost every organ.

Cell-specific signatures in the blood

Researchers found that different types of senescent cells each secrete their own unique protein cocktail. These cell-specific signatures are measurable in the blood. The researchers analysed data from 1,275 participants in the Baltimore Longitudinal Study of Aging and 997 participants from the Italian InCHIANTI study.

The protein patterns associated with senescent cells outperformed other circulating proteins in predicting clinical parameters. They correlated with walking speed, hypertension and biological age, outperforming other circulating markers across multiple clinical measures in this study.

Why this matters for aging research

The ability to measure senescent cell burden by tissue type is valuable for several reasons. First, it may help identify which organs are ageing fastest in a given individual. Second, it offers a potential measurement tool for therapies that specifically target senescent cells, known as senolytics. Until now, a reliable, non-invasive method to assess whether such therapies work has been lacking.

The authors emphasise that this is a first step. Findings are promising, but more validation studies are needed before clinical use. The proteins measured originate from a broad range of cell types, which adds complexity to interpretation.

For longevity science, this work marks an interesting milestone: the idea that aging does not proceed uniformly throughout the body, but can be tracked tissue by tissue through blood.

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