senesenssi

Senesenssi is the Finnish term for senescence, describing aging-related processes that affect cells, tissues, and organisms. In biology, senescence refers to the gradual decline in function associated with age, including a state of permanent cell-cycle arrest in many cell types while metabolism and certain gene activities continue.

In mammals and other organisms, cellular senescence can be triggered by telomere shortening after repeated cell divisions, DNA damage, oxidative stress, or oncogene activation. Key signaling pathways, such as p53/p21 and p16INK4a/Rb, enforce the growth arrest. Senescent cells often acquire a senescence-associated secretory phenotype (SASP), releasing inflammatory cytokines, proteases, and growth factors that influence neighboring cells. Senescence has beneficial roles in preventing cancer and aiding tissue repair, but accumulation of senescent cells with age is linked to chronic inflammation and tissue dysfunction, contributing to age-related diseases. The immune system normally clears many senescent cells, though clearance can decline with age or disease.

In plants, senescence describes the aging of organs such as leaves, flowers, or fruits. Leaf senescence involves nutrient remobilization to developing parts and is regulated by hormones such as ethylene, jasmonates, and cytokinins. Environmental stresses can accelerate senescence, affecting crop yield and quality.

Research on senescence includes developing senolytic drugs that selectively remove senescent cells and senomorphic agents that modulate the SASP, with the aim of mitigating aging-related decline. Common research markers include senescence-associated β-galactosidase activity and p16 expression.