Enrichment and clonal culture of hepatic stem/progenitor cells during mouse liver development

Liver regenerates after hepatectomy or chemical-induced injury. In contrast to cells in other tissues that can regenerate, mature cells (hepatocytes), but not undifferentiated stem cells, are mainly responsible for acute liver regeneration. Liver stem cells take part in liver regeneration in some forms of chronic liver injury, when the proliferative ability of differentiated hepatocytes is impaired. During liver development, both hepatocytes and cholangiocytes are differentiated from common precursor cells, called hepatoblasts. By combining fluorescence-activated cell sorting (FACS) and an in vitro clonal culture system for stem/progenitor cells, we established a method to isolate stem/progenitor cells prospectively from mouse fetal and adult livers. FACS clone-sorted single CD45(-)Ter119(-)c-kit(-)CD13(+)CD133(+) cells (from fetal mid-gestational livers) or CD45(-)Ter119(-)c-kit(-)Sca1(-)CD13(+)CD49f(+)CD133(+) cells (from adult livers) can form a colony containing both albumin-positive hepatocytes and cytokeratin 19-positive bile ductal cells, indicating that these cells have the characters of liver stem/progenitor cells (proliferative capability and bipotency for hepatic and for biliary epithelial differentiation). These cells can maintain these capabilities for several months in culture.