seneszenten

Seneszenten is a term used in German-language literature to describe cells or tissues that have entered senescence, a state of stable cell cycle arrest in response to various forms of stress. While functionally senescent cells stop dividing, they remain metabolically active and often acquire a characteristic secretory profile known as the senescence-associated secretory phenotype (SASP). Senescence can occur in many cell types and contexts, and the term is commonly applied to cells that exhibit these arrested, yet active, properties.

Mechanisms and markers of senescence encompass telomere shortening with repeated cell divisions (replicative senescence), DNA damage responses, oncogene-induced stress, oxidative stress, and other insults. Core signaling pathways involve the p53/p21 and p16INK4a/pRB axes, which enforce cell cycle arrest. Biomarkers frequently used to identify senescent cells include increased activity of senescence-associated beta-galactosidase (SA-β-gal) and elevated expression of p16INK4a. The SASP comprises inflammatory cytokines, matrix-remodeling enzymes, growth factors, and other factors that influence the tissue environment.

Biological roles of senescence are context-dependent. It acts as a tumor-suppressive mechanism by halting the proliferation of damaged cells and contributes to normal development and wound healing. However, the chronic accumulation of senescent cells and their SASP can promote tissue dysfunction, inflammation, and age-related diseases, making senescence a double-edged sword. The immune system normally helps clear senescent cells, but clearance can be imperfect in aging tissues, leading to persistence and deleterious effects.

Research and therapeutic approaches include senolytics, which selectively eliminate senescent cells, and senomorphics, which modulate the SASP without killing the cells. These strategies aim to mitigate age-associated pathology while preserving beneficial aspects of senescence. Detecting and quantifying senescent cells remains an active area of study, with applications in aging research and clinical contexts.