Participation of intra- and extrahepatic stem/progenitor cells in liver regeneration: recent advances
Liver regeneration refers to the rapid proliferation of impaired liver tissue caused by injurious stimulus (surgery, trauma, poisoning, infection, and necrosis, etc.) to increase the volume and weight of the remnant liver. Liver regeneration can be divided into three major levels according to the cause and severity of the injury: hepatocyte dominant regeneration, intrahepatic stem/progenitor cells mediated regeneration, and extrahepatic stem/progenitor cells participative regeneration. Liver regeneration is usually completed by division of the mature liver cells after the liver undergoing mild to moderate injuries. However, when the liver is severely damaged or the proliferation of hepatocytes is strongly inhibited, liver stem/progenitor cells will participate in the liver regeneration process. Besides the participation of the intrahepatic stem cells, the extrahepatic bone marrow-derived stem cells and stem cells reprogrammed from endothelial progenitor cells are also involved in liver regeneration, but the detailed mechanism remains unclear. Here, the authors address the latest focuses on liver regeneration, especially on the stem/progenitor cells participated liver regeneration and its potential clinical application.