STEM CELL Stem cell plasticity

The quintessential stem cell is the embryonal stem (ES) cell which has unlimited self-renewal and multipotent differentiation potential. Stem cells have also been identified in most tissues. Compared with ES cells, tissue specific stem cells have less self-renewal ability and, although they differentiate into multiple lineages, they are not multipotent. A large number of recent published studies have suggested that postnatal tissue specific stem cells may have the ability to generate cells of tissues from unrelated organs, even though the mechanism underlying such ‘‘plasticity’’ is yet to be clarified. We have identified a population of primitive cells in bone marrow or other tissue cultures from normal human, rodent, and possibly other mammals that have, at the single cell level, multipotent differentiation and extensive proliferation potential. These cells have been named Multipotent Adult Progenitor Cell or MAPC. At the meeting updated information will be provided regarding the possible etiology of the cell, i.e. is the cell a culture artifact or does the cell exist as such in vivo. In addition, updated information was provided regarding the potential differentiation ability of MAPCs.