Efficacy of transplanting cryo-preserved and encapsulated xenogeneic fetal liver fragment as an auxiliary liver support in 90%-hepatectomized rats

BACKGROUND/AIMS: Xenogeneic-hepatocyte or liver-fragment transplantation could be an attractive clinical option in hepatic surgery for patients with impaired liver function if xenogeneic hepatocytes or liver fragments could be preserved for lengthy periods and if immunoisolation could be more easily achieved. METHODOLOGY: Porcine fetal and adult livers were used as xenogeneic transplants in rats. The grafts were stored frozen for more than one year in liquid nitrogen. After thawing, they were evaluated histologically and for potential function for auxiliary liver support in 90%-hepatectomized rats. The efficacy of microporous polypropylene membrane as a macrocapsule for immunoprotection was also examined. RESULTS: Frozen liver fragments could be preserved in liquid nitrogen for more than one year. Fetal fragments were better able to survive under the given conditions than the adult fragments. Macrocapsules protected the grafts from xenoantibodies. The survival rate of encapsulated fetal liver fragment-transplanted recipients on the seventh day after 90%-hepatectomy was 72%, while transplant recipients of fragments of fetal-liver, adult-liver, and encapsulated adult-liver, were 0, 0, and 0, respectively. CONCLUSIONS: Porcine fetal liver fragments survived longer in liquid nitrogen than did the adult ones. The fragments retained their capacity to provide auxiliary liver support in 90%-hepatectomized rats.