Purified hematopoietic stem cells can differentiate into hepatocytes in vivo

The characterization of hepatic progenitor cells is of great scientific and clinical interest. Here we report that intravenous injection of adult bone marrow cells in the FAH(-/-) mouse, an animal model of tyrosinemia type I, rescued the mouse and restored the biochemical function of its liver. More over, within bone marrow, only rigorously purified hematopoietic stem cells gave rise to donor-derived hematopoietic and hepatic regeneration. This re sult seems to contradict the conventional assumptions of the germ layer ori gins of tissues such as the liver, and raises the question of whether the c ells of the hematopoietic stem cell phenotype are pluripotent hematopoietic cells that retain the ability to transdifferentiate, or whether they are m ore primitive multipotent cells.