Aging Biology

← Back to Health, Longevity & Biology

Cellular senescence, mitochondria, proteostasis, telomeres, inflammaging, stem cells, SASP, autophagy, and molecular mechanisms of aging.

The biology of aging is no longer viewed as an immutable, programmed countdown, but rather as an evolutionary byproduct. Evolutionary mechanics favor individual survival over group-level benefits, shaping aging through late-acting genetic defects in the selection shadow, metabolic resource allocation trade-offs between reproduction and somatic maintenance, and hyperactive nutrient-sensing pathways. Modern biogerontology has largely replaced the classic free radical theory—redefining reactive oxygen species as critical signaling mediators—in favor of models like the information theory of aging, which attributes cellular decline to epigenetic noise and the loss of cellular data.

At the cellular level, genomic instability, compromised DNA repair capacity, and telomere attrition culminate in cellular senescence. Senescent cells, alongside deteriorating stem cell niches characterized by extracellular matrix stiffening and altered TGF-beta signaling, release a hyper-metabolic cocktail of pro-inflammatory signals and proteases known as the senescence-associated secretory phenotype (SASP). This localized damage, compounded by the activation of transposable elements via the cGAS-STING pathway, drives systemic inflammaging. This sterile, low-grade inflammatory state is further reinforced by immunosenescence, shifts in IgG glycosylation within the human glycome, and dysbiosis of the oral microbiome.

Concurrently, the failure of internal quality control mechanisms—such as proteostasis decline, respiratory supercomplex disassembly, and failed mitophagy—leads to mitochondrial heteroplasmy, energetic collapse, and neurodegenerative protein aggregation. These internal failures propagate outward, causing macrovascular stiffening, endothelial glycocalyx degradation, lymphatic waste-clearance deficits, and intrinsic cardiac decay.

By analyzing these pathways alongside the protective mechanisms of negligibly senescent species, biological sex differences, and systemic mediators—such as circulating blood factors, bone-derived osteocalcin, the longevity protein Klotho, exercise-induced mitohormesis, circadian homeostasis, and metabolic regulators like taurine—this research section maps the molecular networks driving physical decline and the therapeutic interventions poised to restore systemic homeostasis.

47 published articles