Cellular Senescence

Cellular senescence is a biological state in which a cell permanently stops dividing but remains metabolically active and resists cell death. Biologists Leonard Hayflick and Paul Moorhead first described this phenomenon in 1961 after observing that normal human cells in laboratory cultures could only divide a limited number of times before halting. Unlike programmed cell death (apoptosis), which dismantles and removes cells, senescent cells persist in the body. While in this state, they undergo major changes in their structure, shape, and gene activity.

Cells enter senescence in response to various forms of stress and genetic damage. Senescence is often caused by the