Old fat cells, higher disease risk. Scientists uncover an important mechanism

A new study points to ANGPTL8 as a potential link between aging adipose tissue, chronic inflammation, and age-related functional decline.

Old fat cells, higher disease risk. Scientists uncover an important mechanism

Table of contents

    Adipose tissue may actively contribute to aging

    Adipose tissue is not simply a place where the body stores excess energy. It is also an active metabolic and endocrine organ that releases molecules capable of influencing metabolism, immune function, and other tissues.

    As the body ages, some fat cells enter cellular senescence — a state in which cells permanently stop dividing and change the way they function. Senescent cells can begin releasing increased amounts of inflammatory molecules, collectively known as the senescence-associated secretory phenotype, or SASP.

    A new study published in Aging Cell points to one mechanism that may contribute to this process. Researchers identified the protein ANGPTL8 as a potential regulator of adipose tissue aging. Its levels increased with age, while experiments in animals and cells suggest that ANGPTL8 may be more than just a marker of aging — it may actively drive some age-related changes.

    However, there is an important distinction between the different types of evidence. In humans, the researchers primarily found statistical associations, while stronger evidence for a causal role came from experiments in mice and cultured cells.

    Study details

    The study combined population-level human data with animal experiments, single-cell analyses, and laboratory studies. This allowed the researchers to first identify an association between ANGPTL8 and aging and then investigate potential biological mechanisms behind it.

    • Publication title: An ANGPTL8-AKT2-mTOR Axis Drives Adipose Senescence and Aging-Related Functional Decline.
    • Authors: Yi He, Limeng Pan, WenJun Ping, Chen Meng, Xiaoyu Meng, Yaming Guo, and colleagues. The corresponding authors were Danpei Li and Xuefeng Yu.
    • Publication year: 2026.
    • Journal: Aging Cell.
    • DOI: 10.1111/acel.70671.
    • PMID: 42605193.
    • Study type: a translational study combining a human cohort analysis, machine-learning models, genetically modified mice, transcriptomic analyses, and cell experiments.
    • Human population: the China Cardiometabolic Disease and Cancer Cohort included 9,904 participants, with a median age of 60.3 years. Median follow-up was 10 years, during which 1,441 deaths were recorded. ANGPTL8 concentrations were available in a subgroup of 3,637 participants.
    • Experimental intervention: in the animal part of the study, researchers compared mice lacking the Angptl8 gene with wild-type animals. In cell experiments, ANGPTL8 and components of the AKT–mTOR pathway were either increased or inhibited.
    • Main outcome: higher ANGPTL8 levels were associated with biological aging and mortality in humans, while deleting Angptl8 in mice reduced signs of adipose tissue senescence, slowed functional decline, and was associated with longer lifespan.
    • Funding: National Natural Science Foundation of China, grants 82270880, 82470907, and 82400944.
    • Conflicts of interest: the authors declared no conflicts of interest.
    • Full text: Aging Cell
    • PubMed: PMID 42605193

    This combination of observational human data and mechanistic experiments is important. The human data alone cannot establish that ANGPTL8 causes faster aging, but the animal and cellular experiments provide evidence that the protein may actively participate in the process.

    Higher ANGPTL8 was associated with aging and mortality in humans

    For the human portion of the study, researchers analyzed data from a large Chinese cohort and developed machine-learning models designed, among other things, to estimate biological age and 10-year mortality risk.

    ANGPTL8 emerged as one of the relevant variables in these models. For mortality prediction, chronological age remained the strongest predictor, while ANGPTL8 was among the additional variables that contributed useful information.

    The researchers reported several notable associations:

    • Higher ANGPTL8 levels were associated with features of biological aging. As ANGPTL8 increased, participants also tended to have a higher frailty index, reflecting a greater accumulation of health deficits.
    • ANGPTL8 contributed information to mortality prediction models. Other important variables included age, creatinine, systolic blood pressure, and gamma-glutamyl transferase.
    • The combination of older age and higher ANGPTL8 shifted model predictions toward greater mortality risk. This does not mean, however, that lowering ANGPTL8 would necessarily reduce mortality in humans.

    That distinction is crucial. Epidemiological data can show that ANGPTL8 is associated with unfavorable metabolic or aging-related changes, but they cannot by themselves prove that the protein directly causes them.

    Removing ANGPTL8 reduced some signs of aging in mice

    The experimental part of the study provided stronger evidence about a possible biological mechanism.

    Older mice had higher circulating ANGPTL8 levels than younger animals. The researchers therefore generated mice lacking the Angptl8 gene and examined how its absence affected aging.

    Several differences emerged:

    • Mice lacking ANGPTL8 lived longer than control animals. The survival curves separated particularly later in life.
    • They maintained better physical function as they aged. Mice without Angptl8 showed less deterioration in locomotor activity and preserved some measures of functional performance.
    • Their adipose tissue showed fewer signs of cellular senescence. Levels of senescence markers such as p16 and p21 were lower, and fewer cells showed characteristics of senescence.
    • Their adipose tissue showed fewer signs of chronic inflammation. The researchers observed less macrophage infiltration and lower levels of several inflammatory SASP-associated factors.

    This part of the study is important because genetically removing a gene allows researchers to test causality more directly than simply measuring a protein in the bloodstream.

    Researchers identified a potential ANGPTL8–AKT2–mTOR mechanism

    The next question was how ANGPTL8 might influence the aging of fat cells.

    The researchers proposed the following signaling pathway:

    ANGPTL8 → AKT2 → mTOR → S6K

    ANGPTL8 interacted with AKT2 and increased downstream signaling through this pathway. In adipocytes, this was associated with higher levels of senescence markers and increased production of inflammatory SASP factors.

    Several experiments supported this mechanism:

    • Increasing ANGPTL8 activity promoted features of cellular senescence. Cells showed greater SA-β-galactosidase activity and higher levels of markers such as p16 and p21.
    • Blocking AKT weakened the effect of ANGPTL8. The AKT inhibitor MK2206 reduced ANGPTL8-induced senescence-related changes.
    • Inhibiting mTOR produced a similar effect. Rapamycin reduced downstream pathway activation and some of the cellular changes associated with senescence.

    The researchers therefore propose a model in which aging adipose tissue produces more ANGPTL8, which activates AKT–mTOR signaling, promotes adipocyte senescence, increases SASP production, and may ultimately contribute to chronic inflammation.

    What this could mean for longevity

    Perhaps the most interesting part of the study is not simply the identification of another aging biomarker. Instead, it suggests that adipose tissue may actively influence age-related decline throughout the body.

    Fat tissue was once viewed mainly as an energy-storage organ. It is now known to function as an endocrine tissue that communicates with the rest of the body. This study extends that idea by suggesting that aging fat cells may release signals capable of contributing to broader systemic changes.

    The findings have several potential implications:

    • The biological quality of adipose tissue may matter independently of how much fat a person carries. The problem may not be limited to excess fat mass but may also involve changes in how aging adipose tissue behaves and what molecules it releases.
    • Adipocyte senescence may contribute to inflammaging. If aging fat cells produce more SASP factors, adipose tissue could become one source of the chronic, low-grade inflammation associated with aging.
    • ANGPTL8 may become a future therapeutic target. The study provides a biological rationale for testing interventions that modify this pathway, but this remains a research direction rather than an established anti-aging treatment for humans.
    • The mTOR pathway once again appears in aging research. The findings place ANGPTL8 upstream of one of the most extensively studied signaling pathways involved in cellular growth, metabolism, and aging biology.

    More broadly, the study illustrates why longevity research increasingly focuses not only on individual organs but also on communication between tissues. Age-related dysfunction in one cell type may influence the behavior of many other systems.

    The study has important limitations

    The findings are intriguing, but they do not yet justify treating ANGPTL8 as a validated anti-aging target in humans.

    Several limitations are particularly important:

    • The lifespan extension was demonstrated in mice, not humans. Many aging pathways are shared across species, but an effect caused by lifelong genetic deletion in mice does not necessarily translate into a safe or effective intervention in people.
    • The human part of the study was observational. Higher ANGPTL8 could contribute to unfavorable changes, result from them, or simply be part of a broader metabolic disturbance.
    • Genetic deletion is not equivalent to a typical therapy. An animal that lacks a gene throughout its life may develop differently from an adult human whose ANGPTL8 activity is reduced pharmacologically.
    • ANGPTL8 also participates in lipid metabolism. Any attempt to block the protein would therefore require careful evaluation of metabolic effects and safety.
    • Predictive models are not proof of biological mechanism. The fact that ANGPTL8 improves prediction of age-related outcomes does not by itself demonstrate that the protein causes those outcomes.

    For now, ANGPTL8 is best viewed as a promising candidate linking adipose tissue senescence, inflammation, and age-related functional decline. Whether modifying this pathway can improve human healthspan or lifespan remains an open question.

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