Auxiliary transplantation of the fetal liver. I. Development of a sheep model

Current methods of orthotopic liver transplantation are expensive, entail high morbidity and mortality, and are limited by a serious shortage of donor organs for the pediatric recipient. Auxiliary transplantation of livers from anencephalics is a potential solution to the problems of size discrepancy and organ availability for the pediatric patient. To investigate the feasibility of auxiliary fetal liver transplantation, we have developed a sheep model of auxiliary transplantation of the fetal liver into the adult neck. We report here the results of the transplantation of 32 fetal lamb livers ranging in age from 100 to 140 days gestation (term 145 days). We conclude that (1) fetal organ harvest can be effectively accomplished by surface cooling followed by umbilical cold perfusion; (2) auxiliary transplantation of the fetal lamb liver is technically feasible; (3) the fetal liver can survive on umbilical inflow alone but function is improved by hepatic arterial inflow; and (4) the fetal liver is sensitive to excessive flow or pressure and is best transplanted in a parallel vascular arrangement. Auxiliary transplantation of the fetal liver is a promising alternative to current methods of liver transplantation.