Cellular Senescence in Aging Primates

TLDR

Aging involves progressive functional decline across organ systems, and while somatic cells exhibit replicative senescence, its role in organismal aging remains debated. The study examined telomere dysfunction in baboon skin fibroblasts, quantifying senescent cells that rise exponentially with age. Senescent fibroblasts in baboon skin increase exponentially with age, reaching over 15 % in the oldest animals, and display activated ATM kinase and heterochromatinized nuclei.

Abstract

The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. We investigated telomere dysfunction, a recently discovered biomarker of cellular senescence, and found that the number of senescent fibroblasts increases exponentially in the skin of aging baboons, reaching >15% of all cells in very old individuals. In addition, the same cells contain activated ataxia-telangiectasia mutated kinase and heterochromatinized nuclei, confirming their senescent status.