Bioartificial liver: current status

Liver failure remains a life-threatening syndrome. With the growing disparity between the number of suitable donor organs and the number of patients awaiting transplantation, efforts have been made to optimize the allocation of organs, to find alternatives to cadaveric liver transplantation, and to develop extracorporeal methods to support or replace the function of the failing organ. An extracorporeal liver support system has to provide the main functions of the liver: detoxification, synthesis, and regulation. The understanding that the critical issue of the clinical syndrome in liver failure is the accumulation of toxins not cleared by the failing liver led to the development of artificial filtration and adsorption devices (artificial liver support). Based on this hypothesis, the removal of lipophilic, albumin-bound substances, such as bilirubin, bile acids, metabolites of aromatic amino acids, medium-chain fatty acids, and cytokines, should be beneficial to the clinical course of a patient in liver failure. Artificial detoxification devices currently under clinical evaluation include the Molecular Adsorbent Recirculating System (MARS), Single-Pass Albumin Dialysis (SPAD), and the Prometheus system. The complex tasks of regulation and synthesis remain to be addressed by the use of liver cells (bioartificial liver support). The Extracorporeal Liver Assist Device (ELAD), HepatAssist, Modular Extracorporeal Liver Support system (MELS), and the Amsterdam Medical Center Bioartificial Liver (AMC-BAL) are bioartificial systems. This article gives a brief overview on these artificial and bioartificial devices and discusses remaining obstacles.