Senescent cells are cells that have permanently stopped dividing but resist apoptosis, secreting a pro-inflammatory cocktail (SASP) that damages surrounding tissues. Clearing senescent cells in mice extends healthspan and lifespan, and early human senolytic trials are underway.
Senescent cells are cells that have permanently exited the cell cycle in response to DNA damage, telomere shortening, or oncogenic stress. They resist apoptosis (programmed cell death) and secrete a pro-inflammatory cocktail of cytokines, chemokines, and proteases called the Senescence-Associated Secretory Phenotype (SASP). SASP damages surrounding tissues, promotes chronic inflammation, and impairs tissue regeneration. Clearing senescent cells in mice dramatically improves healthspan and extends lifespan.
Baker et al. (2011) in Nature demonstrated that clearing senescent cells in a mouse model of accelerated aging delayed the onset of age-related pathologies (cataracts, muscle wasting, fat loss) and extended median lifespan. A follow-up study (Baker et al., 2016) showed that clearing senescent cells in naturally aged mice extended median remaining lifespan by 25% and reduced cancer incidence. Kirkland et al. (2017) reviewed the evidence for senolytic drugs (dasatinib + quercetin, navitoclax) in humans, noting that early clinical trials showed reductions in senescent cell burden and SASP markers in patients with idiopathic pulmonary fibrosis and diabetic kidney disease.
"Clearing senescent cells in naturally aged mice extended median remaining lifespan by 25% and reduced cancer incidence."
— Baker et al., Nature 2016
The NIA identifies cellular senescence as one of the hallmarks of aging and a major focus of longevity research. The NIA is funding multiple clinical trials of senolytic drugs (drugs that selectively kill senescent cells) in conditions including Alzheimer's disease, osteoarthritis, and frailty. MedlinePlus notes that cellular senescence is an active area of aging research with potential therapeutic implications.
No senolytic drugs are currently approved for clinical use in healthy humans. Dasatinib + quercetin and navitoclax are the most studied senolytics, with early human trials showing reductions in senescent cell markers. Quercetin is available as a supplement, but its senolytic activity at supplement doses is unproven in humans. The most practical approach to reducing senescent cell accumulation is preventing the stresses that drive senescence: avoiding DNA damage (smoking cessation, sun protection), reducing chronic inflammation (Mediterranean diet, exercise), and maintaining metabolic health.
Vitaei verdict
Senescent cells are a causal driver of aging with compelling animal evidence. Human senolytic trials are early-stage. No senolytic drugs are approved for healthy adults; lifestyle approaches to reducing senescent cell accumulation are the most practical current strategy.
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