X-Message-Number: 27869
Date: Mon, 24 Apr 2006 19:40:46 -0700 (PDT)
From: Doug Skrecky <>
Subject: old animals have more "old" cells

[The accumulation of post-mitotic "senescent" cells may be partly an
artifact due to reduced proliferation of stem cells.]

Science. 2006 Mar 3;311(5765):1257. Epub 2006 Feb 2.
Cellular senescence in aging primates.
  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.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=27869