The neural stem cells and their transdifferentiation capacity

Stem cells play a critical role during embryo and tissue formation througho ut development. Thanks to their multipotentiality - i.e., the ability to gi ve rise to different lineages of mature cells - and to their extensive capa city for self-renewal and expansive growth, stem cells can also contribute to the maintenance of tissue integrity in adulthood. Historically, it has b een held that fetal and adult (somatic) stem cells are tissue-specific 'ent ities' whose differentiation potential is limited to the generation of matu re cell types of the tissue/organ in which they reside. Yet, recent years h ave seen the publication of an impressive sequence of reports dealing with what is now emerging as one of the most striking functional attributes of s omatic stem cells, that is, their capacity to undergo transdifferentiation. Thanks to this peculiar characteristic adult stem cells display an unexpec ted ability to give rise to differentiated cells of tissues and organs diff erent from those in which they reside. This commentary briefly illustrates the characteristics of the neural stem cell and its capacity as a neuroecto dermal derivative to undergo transdifferentiation, thus giving rise to diff erentiated cells that normally originate from the mesoderm, like blood or s keletal muscle cells. (C) 2001 Editions scientifiques et medicales Elsevier SAS.