Orthotopic
liver transplantation is the most effective treatment for
fulminant hepatic failure. As an alternative treatment, an efficient extracorporeal
bioartificial liver should contain a large yield of functional hepatocytes with an immunoprotective barrier, for providing temporary adequate metabolic support to allow spontaneous liver regeneration or for acting as a bridge toward
transplantation. Survival, proliferation, and functions of porcine hepatocytes were evaluated in primary cultures and after embedding in
alginate beads, which were subsequently coated with a membrane made by a transacylation reaction between
propylene glycol alginate and
human serum albumin. Disruption of total pig livers by
collagenase perfusion/recirculation allowed the obtention of up to 10(11) hepatocytes with a viability greater than 95%. Hepatocytes in conventional cultures or embedded in coated
alginate beads survived for about 10 days, secreted
proteins, particularly
albumin, and maintained several phase I and II enzymatic activities, namely
ethoxyresorufin-O-deethylase, oxidation of
nifedipine to
pyridine,
phenacetin deethylation to
paracetamol, glucuroconjugation of
paracetamol, and N-acetylation of
procainamide. Typical features of mitosis and [3H]
thymidine incorporation indicated that porcine hepatocytes proliferated in both conventional cultures and
alginate beads. The efficacy of the membrane surrounding
alginate beads for protecting cells from
immunoglobulins was tested by embedding HLA-typed human lymphocytes, which were subsequently incubated with specific anti-HLA
immunoglobulin G and
complement. These data show that large yields of porcine hepatocytes that are embedded in coated
alginate beads remain functional and are isolated from large molecular weight molecules, such as
immunoglobulins. This system represents a promising tool for the design of an extracorporeal
bioartificial liver, containing xenogeneic hepatocytes, to treat acute
liver disease in humans.