Cell transplantation as a non-invasive strategy for treating liver fibrosis.

Advancements in antiviral drugs have enabled control of viral hepatitis; yet, many patients with liver cirrhosis (LC) are awaiting liver transplants. Liver transplantation yields dramatic therapeutic effects, but problems such as shortage of donors, surgical invasiveness, immunological rejection and costs, limit the number of transplantations. Advances in liver regeneration therapy through cell transplantation as a non-invasive treatment for cirrhosis will supplement these restrictions to the number of liver transplants. Clinical trials for LC have included hematopoietic stem cell mobilization by administration of granulocyte colony-stimulating factor, infusion of autologous bone marrow cells, and administration of autologous mesenchymal stem cells derived from bone marrow or umbilical cord. Several recently reported randomized controlled studies have shown the effectiveness of these approaches. However, to promote implementation of new liver regeneration therapies, it is important to develop a system whereby cell therapies with ensured safety can be approved quickly.