In vivo evaluation of a hollow fiber liver assist device

Orthotopic liver transplantation is the only effective form of therapy currently available for patients with fulminant hepatic failure (FHF). The use of an extracorporeal (EC) liver assist device (LAD) may result in improved presurgical clinical management. Alternatively, patients treated with LADs could avoid the transplantation procedure if they are able to regenerate a critical mass of hepatocytes that will sustain functional viability. In this study, the efficacy of a prototype hollow fiber LAD seeded with rabbit hepatocytes was assessed in vivo by the use of two different animal models: (1) normal rabbits injected with diazepam or lidocaine, and (2) a galactosamine (Gal)-intoxicated rabbit model of FHF. The EC LAD clearly decreased the blood levels of the two drugs and significantly generated diazepam and lidocaine metabolites indicating the maintenance of active P450 forms in the cellular component of the devices. A 6-hour EC treatment significantly increased the survival time and delayed the onset of hepatic encephalopathy (HE) in the Gal-intoxicated rabbits. Histological evaluations of postmortem livers showed greater hepatocyte regenerative activity in the animals treated with hepatocyte-seeded LADs than in the two control groups, e.g., rabbits not treated or treated with unseeded devices. These findings support the concept that a microporous hollow fiber LAD seeded with rabbit hepatocytes is able to sustain drug detoxification in vivo as well as to modify the course of FHF in a well-characterized animal model.