IS THE BIOLOGICAL ARTIFICIAL LIVER CLINICALLY APPLICABLE - A HISTORICREVIEW OF BIOLOGICAL ARTIFICIAL LIVER SUPPORT SYSTEMS

Hemoperfusion, hemodiafiltration, plasma exchange, and extracorporeal liver perfusion have already been adopted to treat patients with acute and chronic hepatic failure. However, the survival rate of patients w ith acute hepatic failure remains at approximately 30% and has not imp roved as expected. Current advances in biotechnology have opened the w ay for the development of a biological artificial liver, which is call ed the hybrid artificial liver because it consists of both biological and artificial materials. Isolated hepatocytes have been investigated for use in various types of hybrid artificial liver. In addition, the role of biomatrices, microcarriers, and the microencapsulation techniq ue has been studied with respect to long-term maintenance of hepatocel lular function and development of high-density culture systems for hep atocytes. Before clinical application of hybrid artificial liver suppo rt systems becomes possible, many problems have to be resolved, includ ing large-scale preparation and long-term preservation of biomaterials , high-density and stable immobilization of biomaterials on artificial materials, control of immunological hazards, biocompatibility, safe t ransportation and sterilization of biomaterials, and the high cost. We review the history of biological artificial livers and discuss their future role.