Bioartificial liver support: developments in hepatocyte culture and bioreactor design

Bioartificial liver devices aim to support patients with acute liver failure (ALF) until orthotopic liver transplantation (OLT) or spontaneous recovery due to hepatic regeneration can occur. However, initial clinical experiences with two devices have indicated that functional efficacy in this setting may be less than in the experimental situation. Several fundamental issues remain unresolved, including the cell mass required to provide meaningful support and which of those hepatocyte components and bioreactor designs so far proposed is best able to do this. In particular, further studies of the efficacy of devices incorporating human hepatocyte lines transformed by either cultural conditions or genetic engineering and those based on multi-channel or flat bed bioreactor designs in which hepatocytes are co-cultured with non-parenchymal cells are awaited. Controlled trials on a multicentre basis in well-defined patient groups and with standardised outcome measures will be required to properly evaluate the clinical value of these devices. A better understanding of factors promoting recovery and regeneration of the native liver and to what extent these can be provided by extracorporeal devices will be essential to the further development of effective bioartificial liver support systems.