Flow-cytometric separation and enrichment of hepatic progenitor cells in the developing mouse liver

Stem cells responsible for tissue maintenance and repair are found in a num ber of organs. However, hepatic stem cells assumed to play a key role in li ver development and regeneration remain to be well characterized. To addres s this issue, we set up a culture system in which primitive hepatic progeni tor cells formed colonies. By combining this culture system with fluorescen ce;activated cell sorting (FACS), cells forming colonies containing distinc t hepatocytes and cholangiocytes were identified in the fetal mouse liver. These cells express both CD49f and CD29 (alpha6 and beta1 integrin subunits ), but do not mark for hematopoietic antigens such as CD45, TER119, and c-K it. When transplanted into the spleen, these cells migrated to the recipien t liver and differentiated into liver parenchymal cells. Our data demonstra te that hepatic progenitor cells are enriched by FAGS and suggest approache s to supplanting organ allografting and improving artificial-organ hepatic support.