Artificial liver support: quo vadis?

Approximately 2 million persons worldwide die each year from hepatic failure. Because of the scarcity of donor organs, artificial liver support systems are being developed with the aim of either supporting patients with borderline functional liver cell mass until an appropriate organ becomes available for transplantation or until their livers recover from injury.

A literature review was performed using MEDLINE, PubMed, EMBASE, and library searches. Only major liver support techniques are included in this review.

A number of extracorporeal liver assist systems are in various stages of clinical development. Published data indicate that patients with acute and acute-on-chronic liver failure may benefit from treatment with some of these therapeutic measures. Results from large prospective randomized trials have shown that treatment with MARS® and PROMETHEUS® may not confer a survival advantage, despite positive effects on blood toxemia and improvement in hepatic encephalopathy. Currently, hemofiltration using albumin-leaking membranes is being explored as a novel promising approach to blood purification in liver failure.

Developing an effective liver assist technology has proven difficult, because of the complexity of liver functions that must be replaced, as well as heterogeneity of the patient population. Non-biological systems may have a role in the treatment of specific forms of liver failure where the primary goal is to provide blood detoxification/purification. Biological systems appear to hold promise for treating liver failure where the primary objective is to provide whole liver functions which are impaired or lost.