[Regeneration of the liver: from hepatocyte cells to deficient hepatic cells]

Regenerative medicine aims to restore the function of a deficient organ without replacing it, i.e. without resection-transplantation, but by the use of healthy cells which will transfer the deficient function inside the diseased organ. Cells can be mature, harvested directly from the source tissue, or be instead produced from stem cells, which can be manipulated in vitro, expanded and/or differentiated to render them functional. Liver cell therapy has brought the proof of concept that a deficient metabolic activity can be transferred via transfusion of heterologous liver cells via the portal vein. The main limitations of the technique include organ shortage, poor renewal capacity of mature cells and poor resistance to cryopreservation. A liver derived progenitor cell has recently been identified in the adult human liver. The cell is selected by a culture process, can be expanded in vitro and differentiated into mature human hepatocytes when transplanted in rodent livers. The cell displays all the essential hepatocyte function, and may replace the mature hepatocyte for regenerative medicine of the liver.