ObjectiveTo test the safety and efficacy of a bioartificial liver support system in patients with severe acute liver failure. Summary Background DataThe authors developed a bioartificial liver using porcine hepatocytes. The system was tested in vitro and shown to have differentiated liver functions (cytochrome P450 activity, synthesis of liverspecific proteins, bilirubin synthesis, and conjugation). When tested in vivo in experimental animals with liver failure, it gave substantial metabolic and hemodynamic support. MethodsSeven patients with severe acute liver failure received a double lumen catheter in the saphenous vein; blood was removed, plasma was separated and perfused through a cartridge containing 4 to 6 X 109 porcine hepatocytes, and plasma and blood cells were reconstituted and reinfused.Each treatment lasted 6 to 7 hours. ResultsAll patients tolerated the procedure(s) well, with neurologic improvement, decreased intracranial pressure (23.0 ± 2.3 to 7.8 ± 1.7 mm Hg; p < 0.005) associated with an increase in cerebral perfusion pressure, decreased plasma ammonia (163.3 ± 21.3 to 1 12.2 ± 9.8 ,uMoles/L; p < 0.01), and increased encephalopathy index (0.60 ± 0.17 to 1.24 ± 0.22; p < 0.03). All patients survived, had a liver transplant, and were discharged from the hospital.

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Orthotopic liver transplantation (OLT) is the only effective therapeutic modality in severe acute hepatic failure (AHF). The scarcity of organs for transplantation leads to an urgent necessity for temporary liver support treatments in AHF patients. A hepatocyte-based bioartificial liver (BAL) is under investigation with the main purpose to serve as bridging treatment until a liver becomes available for OLT, or to promote spontaneous liver regeneration. We developed a novel radial-flow bioreactor (RFB) for three-dimensional, high-density hepatocyte culture and an integrated pumping apparatus in which, after plasmapheresis, the patient's plasma is recirculated through the hepatocyte-filled RFB. Two hundred thirty grams of freshly isolated porcine hepatocytes were loaded into the RFB for clinical liver support treatment. The BAL system was used 8 times in supporting 7 AHF patients in grade III-IV coma, all waiting for an urgent OLT Three patients with no history of previous liver diseases were affected by fulminant hepatic failure (FHF) due to hepatitis B virus, 3 by primary non-function (PNF) of the transplanted liver, and one by AHF due to previous abdominal trauma and liver surgery. Six out of 7 patients underwent OLT following BAL treatment(s), which lasted 6-24 hours. All patients tolerated the procedures well, as shown by an improvement in the level of encephalopathy, a decrease in serum ammonia, transaminases and an amelioration of the prothrombin time, with full neurological recovery after OLT Our initial clinical experience confirms the safety of this BAL configuration and suggests its clinical efficacy as a temporary liver support system in AHF patients.

Rat liver ultrastructure was investigated after partial hepatectomy (PH), by scanning and transmission electron microscopy. Portal pressure was monitored before and after PH and, after killing performed at 6, 12, 24, 48 h and 10 d, regenerating livers were fixed by portal vein perfusion under haemodynamic conditions identical to those existing in vivo. An early and persistent increase in portal pressure after PH was found (P 0.01 for normal vs sham-operated controls). Ultrastructural study showed sinusoid dilatation and disappearance of the sieve-plate arrangement of small endothelial pores, thus leaving the parenchymal liver cell surface directly exposed to portal blood. Widening of sinusoids, endothelial fenestrations, intercellular spaces and spaces of Disse, was accompanied by dilatation of bile canaliculi. At 10 d, liver ultrastructure had returned to normal. Our observations suggest that a rise in portal pressure, as a consequence of PH, may be related to the observed ultrastructural changes in the liver.