Stem Cells Getting Old

Iowa City, IA-

Although autologous bone marrow is currently investigated clinically for numerous indications, one of the fears is that old stem cells may lose regenerative ability with age, and as a result be less effective as opposed to other stem cell sources such as cord blood. A recent publication (Zheng et al. Impact of aging on rat bone marrow-derived stem cell chondrogenesis. J Gerontol A Biol Sci Med Sci. 2007 Feb;62(2):136-48) assessing ability of mesenchymal stem cells generated from the bone marrow to differentiate into cartilage seems so support the notion of age-related diminishment of stem cell activity.

Mesenchymal stem cells generated from 1-week-old rats were compared with 12 week old, and 1 year old rats for ability to differentiate into cartilage, as well as generate produce extracellular matrix as detected by RT-PCR for transcripts of link protein, type II collagen, and aggrecan.

An age-dependent decline in ability to differentiate into chondrocytes, as well as production of ECM proteins was detected. This study provides a good model system for investigating methods of “rejuvenating” cells through use of histone deacetylase inhibitors or cytoplasmic transfer.