Acute liver failure: targeted artificial and hepatocyte-based support of liver regeneration and reversal of multiorgan failure.

Acute liver failure (ALF) still represents a major therapeutic challenge for hepatologists due to its high mortality rate as a result of multiorgan failure. Although emergency orthotopic liver transplantation represents a major advance in the management of selected patients, it is not applicable to all candidates due to limited organ availability. Therefore, new therapeutic options should be developed to bridge selected patients to transplantation or to treat patients not candidates for liver transplantation. Although new techniques for cell culture and perfusion have resulted in a number of promising devices for the provision of temporary liver support in acute liver failure, their clinical efficacy is as yet uncertain. Controlled trials on a multi-centre basis in well-defined patient groups and with standardised outcome measures, including the extent to which treatment influences cell damage and regeneration and prevents or reverses multiorgan failure, will be essential to properly evaluate the clinical value of current and evolving artificial and bioartificial devices. The same considerations must also apply to the assessment of therapeutic efficacy of hepatocyte transplantation. A better understanding of mechanisms responsible for the development of liver cell death, along with cellular and molecular mechanisms allowing surviving cells to proliferate in a hostile environment, will be required if a more targeted therapeutic approach to decreasing hepatocellular injury and enhancing liver regeneration is to be achieved. Whether extracorporeal devices or the transplantation of primary hepatocytes, stem cells or cells genetically engineered to over-express key metabolic functions, a proliferative phenotype and/or cytoprotective pathways will be best suited to meeting these demanding challenges remains to be determined.