Correction of an inborn error of metabolism by intraportal hepatocyte transplantation in a dog model.

The aims of this study were (1) to assess portal hemodynamics during intraportal hepatocyte transplantation (HTX) in dogs, (2) to evaluate a new method for the detection of transplanted hepatocytes using 5-bromo-2'-deoxyuridine (BrdU) incorporation, and (3) to determine the metabolic effects of HTX on an inborn error of the purine metabolism in dalmatian dogs. HTX was performed by intraportal infusion of freshly isolated allogeneic beagle hepatocytes. Portal flow and pressure were monitored continuously during HTX. For the detection experiments, beagles received hepatocytes that had been exposed to BrdU during regeneration of the donor liver, induced by partial hepatectomy. For metabolic studies, dalmatian dogs were used as recipients. Repetitive HTX was performed. As judged by the portal hemodynamics, the number of hepatocytes that could be infused safely varied from 5 x 1O(8) to 8 x 1O(8) in beagles, to 1 x 10(9) in dalmatians. Transaminase levels showed a 5- to 6-fold increase (P=0.05) after HTX, but normalized within 3 weeks. BrdU-positive cells were identified in the recipient livers 2 weeks after HTX and 5-10% of the total amount of transplanted hepatocytes was retrieved. A significant (P=0.05) decrease in serum uric acid was demonstrated after repeated HTX in dalmatians. In conclusion, (1) intraportal HTX is feasible, but portal hypertension limits the maximum amount of hepatocytes that can be infused in one HTX; (2) BrdU labeling is an attractive method for the detection of transplanted hepatocytes in the recipient liver; and (3) after two consecutive hepatocyte transplantations, a temporary correction of the purine metabolism was accomplished in the dalmatian dog.