Stem cell therapy for human liver cirrhosis: a cautious analysis of the results.

End-stage liver disease, and in particular human liver cirrhosis, represents a worldwide health problem. Currently, liver transplant is the only effective treatment, but it is affected by many problems, including relative lack of donors, operative damage, risk of rejection, and high costs. Stem cell therapy is very attractive in this setting because it has the potential to help tissue regeneration while providing minimally invasive procedures and few complications. Only a few clinical studies on the administration of bone marrow-derived stem cells to cirrhotic patients have been published up to now. Although preliminary results seem to be encouraging, the number of treated patients is too small and the study design not completely appropriate to demonstrate safety and efficacy of stem cell therapy in liver cirrhosis. Well designed, randomized, controlled studies are needed to confirm preliminary results and eventually clear doubts.