They’re commonly known as “zombie cells,” but senescent cells are no work of fiction. Discovered in the early 1960s by Leonard Hayflick and Paul Moorhead, senescent cells are cells that remain metabolically active despite being damaged or stressed to the point that they permanently stop dividing. Unlike healthy cells, senescent cells no longer function normally and cannot continue the process of replication. Instead, they linger in tissues throughout the body, secreting a mix of inflammatory molecules known as the senescence-associated secretory phenotype (SASP).
Initially, cellular senescence serves an important protective role, helping prevent damaged cells from becoming cancerous and supporting processes such as wound healing. However, the accumulation of senescent cells over time can become harmful, especially as natural clearance mechanisms, including immune system activity, decline with age. Senescent cells and SASP contribute to tissue damage, promote senescence in neighboring cells, and are increasingly associated with chronic inflammation and age-related diseases.
But researchers are exploring whether senolytics may offer a way to address this process.
