Aged fat cells fuel inflammation via blood protein

The aging of fat tissue is not a harmless process. Like other cells, fat cells can enter a state of permanent arrest known as senescence. These cells stop dividing but remain metabolically active, continuing to secrete substances. The study identifies a specific substance that senescent fat cells release into the bloodstream: the protein ANGPTL8.

What ANGPTL8 does

ANGPTL8 normally regulates fat storage and lipid metabolism. But when too much of it circulates, that regulation appears to go awry. In both cohort studies in humans and in a mouse model, higher concentrations of ANGPTL8 were associated with age-related diseases and increased mortality. Senescence of fat cells, the ‘freezing’ of those cells in a damaged state, is one of the suspected sources of this excess.

This mechanism fits into the broader narrative of inflammaging: the chronic, low-grade inflammation that increases with age and is considered a driver of a range of age-related diseases. Senescent cells secrete pro-inflammatory substances, collectively known as the SASP (senescence-associated secretory phenotype). ANGPTL8 appears to be part of that profile specifically in fat cells.

Humans and mice

The study combined data from cohort studies (in which large groups of people are followed over time) with mouse model experiments. That is a strong combination for early-stage research. The usual caveats still apply: associations in cohort research do not prove causation, and mouse models do not automatically translate to humans.

For those looking through a longevity lens, this is an interesting signal. If senescent fat tissue increases disease risk via ANGPTL8, that offers a potential target for interventions aimed at clearing or suppressing senescent cells. Whether that works in practice requires further research.

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