ABSTRACT
For many years it has been assum ed that the m ajority o f toxins which cause coma in hepatic failure are small dialyzable molecules. As a result, most liver support systems and therapeutic regimens relied primarily on blood detoxification. However, the pathogenesis o f acute liver failure is complex and many investigators, including ourselves, have argued that isolated viable hepatocytes should be used to construct a liver support system to pro vide not only detoxification, but also missing liver synthetic functions. This suggests that a clear distinction should be made between systems designed to strictly “purify” patient blood from toxins and devices incorporating liver tissue preparations to carry out detoxification and provide synthetic function. The former are based on the artificial kidney principle; a classic example is hemodialysis, which was first applied by Kiley et al, and hemoperfusion, which was first tried by Schechter et al using cationic resins and several years later by Yatzidis and Chang et al using activated charcoal.1'4 The latter include biological components (isolated hepatocytes, liver tissue slices) and are thus truly “bioartificial”. In our opinion, the prefix “hybrid” should be used when both living, e.g., isolated hepatocytes and mechanical, e.g., adsorptive column, parts are used in combination to design a liver support system.
