Intrahepatic hepatocyte transplantation following subtotal hepatectomy in the recipient: A possible model in the treatment of hepatic enzyme deficiency

Orthotopic liver transplantation as treatment for hereditary enzyme deficiences in the absence of cirrhosis suffers from significant operative risks, complications, and donor shortages. Transplantation of isolated hepatocytes (HTX) may offer opportunities for the treatment of these diseases and retain the recipient liver. Hepatocytes transplanted into the portal vein, spleen, or omentum lack and ideal growing environment for cell proliferation and maintenance. Therefore, we investigated a method combining 75% recipient hepatectomy with direct injection of hepatocytes into the remaining 25% of liver parenchyma to provide proliferative stimuli and a stable environment during and following liver regeneration. Recipient Gunn rats (glucuronyltransferase deficiency and hyperbilirubinemia) underwent hepatectomy before HTX by direct injection of 10⁷ isolated hepatocytes into the remaining parenchyma. Inbred male Wistar and Gunn rats were used as normal and control hepatocyte donors and saline injection served as a sham transplant control. Isolation of donor hepatocytes was performed with a two-step collagenase digestive method (Seglen) with cell viability of 85% to 95%. Liver regeneration was complete by 2 weeks posttransplant. Four weeks following HTX, total serum billirubin and qualitative bile analysis were performed. A significant decrease in total serum bilirubin levels was observed in Gunn rats receiving Wistar hepatocytes compared with those receiving Gunn hepatocytes and saline control. Bile analysis from HTX rats demonstrated a normal pattern containing bilirubin monoglucuronides and diglucuronides (conjugated bilirubin) in the rats receiving Wistar hepatocytes, whereas the control group receiving Gunn hepatocytes or saline injection demonstrated only unconjugated bilirubin. No differences in histological appearance were noted between groups. We conclude that partial hepatectomy may provide the required stimulus for proliferation of transplanted hepatocytes and the liver may provide the necessary environment for optimal hepatocyte function and bile excretion following transplantation.