[The current and future aspects of liver cell transplantation]

Our previous experiment presented that isolated adult rat hepatocytes survived and proliferated markedly and they reconfigured macroscopic hepatic tissue occupying more than 50% of the spleen 27 months after transplantation. On the basis of the results, we have emphasized that the hepatized spleen provides many fundamental and clinical interests on hepatology. The morphlogical studies of the recomposed hepatic tissue revealed almost normal architecture of the liver except the lack of bile duct system. Prolongation of the survival time was obtained in rats with hepatized spleen which underwent a portacaval shunt several months earlier compared with animals without hepatized spleen, when the rats were completely devascularized. That means that the hepatized spleen can act as an auxillary liver. For the purpose of applying this experimental model clinically, liver cell autotransplantation was performed using dog and monkey. These resulted in recomposed hepatic tissue in the monkey's spleen 15 months after transplantation, but no survival of the transplanted hepatocytes in dogs. In human, we have been developed a new hepatocyte isolation technique and we can obtain approximately 10(6) isolated human hepatocytes (viability 55-86%) from the partially resected liver with the hand-made multiperfusion system. Finally, future problems of clinical application of the intrasplenic hepatocyte transplant were mentioned especially about the idea of the liver cell bank.