Stem cell plasticity and tissue bioengineering: Great expectations and some concerns

Stem cells are by definition cells that self-renew and that have the capacity to differentiate into several lineages. A recent series of studies has challenged fundamental concepts of stem cell biology by suggesting that the functional potential of stem cells is not restricted to the tissue source from which they are derived. The ability for cells of one tissue to produce cells of other developmentally unrelated tissues has been defined as cellular plasticity. Therefore, the utility of stem cell plasticity in cell replacement therapy should be unlimited. Multipotent stem cells may be used to develop replacement tissues for congenital or degenerative disorders, either on their own or in combination with other therapeutic approaches such us gene therapy. There are, however, several concerns regarding the concept of stem cell plasticity and the methods used to evaluate the starting population. (C) 2002 Prous Science. All rights reserved.