Senescent cells are not inactive; they are metabolically active and secrete inflammatory molecules known as SASP (Senescence-Associated Secretory Phenotype). This initially helps clear damage, but as these cells accumulate with age, the chronic inflammation they cause can worsen diseases like Alzheimer's, heart disease, and liver fibrosis.
The physical decline, decreased mobility, and frailty common in the elderly, even without a specific diagnosed disease, can be directly attributed to the accumulation of senescent cells. This links a macro-level health observation to a specific cellular process, identifying a tangible target for therapeutic intervention against age-related weakness.
Cellular senescence is a biological process that permanently halts cell division. Contrary to being just a sign of aging, its primary function is to prevent damaged cells from becoming cancerous. It's a protective measure that stops unchecked proliferation when a cell cannot repair its own damage or undergo programmed cell death.