Extracorporeal liver support: waiting for the deciding vote

Area of Science:

• Hepatology and Regenerative Medicine
• Biomedical Engineering and Device Development

Background:

• Acute liver failure (ALF) has a high mortality rate, historically addressed by liver support systems since the 1950s.
• Early liver support devices proved inefficient, leading to the abandonment in favor of liver transplantation (LT).
• Organ shortage for LT has revived interest in liver support as a bridge to transplantation or regeneration.

Purpose of the Study:

• To review the evolution and current status of liver support devices for acute liver failure.
• To discuss the challenges and concerns associated with both artificial and bioartificial liver devices.
• To highlight the need for robust clinical trials to establish the efficacy of emerging liver support technologies.

Main Methods:

• Review of historical and contemporary liver support technologies, including extracorporeal liver perfusion (ECLP) and bioartificial liver devices (BLD).
• Classification of devices based on the presence or absence of hepatocytes.
• Analysis of preliminary clinical experiences and identified concerns with various device types.

Main Results:

• Hepatocyte-free artificial livers (e.g., MARS) show encouraging results based on toxin adsorption.
• Hepatocyte-based bioartificial liver devices (BLD) and improved ECLP show promise in bridging patients to LT.
• Despite clinical improvements, most studies involve small patient numbers, lacking statistically significant evidence.

Conclusions:

• Current liver support devices demonstrate potential but lack conclusive evidence of benefit.
• Significant concerns remain regarding artificial livers' lack of metabolic activity and BLD's hepatocyte mass and safety.
• Future trials require larger patient cohorts, standardized protocols, and clear definitions of treatment success for definitive conclusions.