Hematopoietic stem cells: Self-renewing or aging?

Stem cells are defined by their extensive self-renewal properties, and yet there is abundant evidence of erosion of stem cell functioning during aging. Whereas intracellular repair and protection mechanisms determine the lifespan of an individual cell, here an argument is made that somatic stem cells determine the lifespan of an entire tissue, and thus play a key role in the organismal aging process. Recently it has been shown that the developmental potential of somatic stem cells may be far greater than previously anticipated. Although the mechanisms regulating stem cell plasticity are far from clear, it is challenging to discuss the potential relevance of these findings in the aging process. Copyright (C) 2002 S. Karger AG, Basel