The current state of liver regeneration therapy

Abstract

Recent advancements of antiviral agents have enabled control of viral hepatitis. Meanwhile, liver cirrhosis caused by alcohol abuse or nonalcoholic steatohepatitis is continuing to increase; still, many patients with decompensated liver cirrhosis are awaiting liver transplants. Liver transplantation yields dramatic therapeutic effects, but problems such as shortage of donors, surgical invasiveness, immunological rejection, costs limit the number of transplantations. Basic studies and clinical trials of liver regeneration therapy through stem cell transplantation are advancing to supplement this restriction to the number of liver transplants. Clinical trials for liver cirrhosis have mainly utilized autologous bone marrow cells as a source of stem cells. Several recently reported randomized controlled studies have shown the effectiveness of these approaches. However, these studies differed in terms of the cell preparations utilized. Future clinical trials should be standardized in terms of cell numbers and injection route. With the advent of induced pluripotent stem cells, liver regeneration therapy has entered a new phase. The generation of a liver bud from induced pluripotent stem cells was reported, and a concept of organ bud transplantation therapy has been advocated. In Japan, the regulations have been revised to facilitate the implementation of regenerative medicine. These efforts towards early implementation may serve as a model for fast-tracking the implementation of new liver regeneration therapies.