Cellular aging

Aging is associated with the gradual accumulation of irreversible physiological changesthat ultimately result in susceptibility to death. To date, the most widely accepted theories ofaging that explain cellular aging are categorized into structural damage and programmedtheories. A wide range of aging causes can be classified into four major groups: free radicals,glycation, telomere shortening, and accumulation of toxic and non-toxic garbage. These extrinsicand intrinsic factors collectively stimulate physiologic stresses to all types of cells. Postmitoticand mitotic cells conferring different proliferative capacity, undergo aging in response to thesestresses via distinct mechanisms of cell death and cellular senescence, respectively. Theprogressive accumulation of these aged cells eventually contributes to dysfunction of agedtissues. Key words: Cellular aging, Cellular senescence, Apoptosis