Cryopreserved mouse hepatocytes retain regenerative capacity in vivo

Background & Aims: Substitution of hepatocyte transplantation for whole liv er transplants in selected individuals with liver disease could significant ly expand the number of patients to benefit from use of scarce donor livers . However, successful hepatocyte transplantation may require that donor cel ls retain normal functional and proliferative capabilities and that they be readily available. Banking of cryopreserved hepatocytes would fulfill the latter requirement. Cryopreservation protocols have been developed that min imize hepatocyte injury and allow preservation of metabolic activity. The a im of this study was to assess cryopreserved hepatocyte proliferative capac ity in vivo after thawing. Methods: Fresh and frozen/thawed mouse hepatocyt es were transferred separately into the livers of recipient mice with trans gene-induced liver disease, an environment that is permissive for clonal ex pansion of donor cell populations. Fresh and cryopreserved donor cells were compared for their ability to proliferate and replace damaged parenchyma. Results: Although cryopreservation decreased hepatocyte viability, individu al viable frozen/thawed hepatocytes demonstrated clonal replicative potenti al identical to that: of fresh hepatocytes. Even after storage for 32 month s in liquid nitrogen, transplanted hepatocytes constituting 0.1% of total a dult hepatocyte number could repopulate a mean of 32% of recipient liver pa renchyma. Conclusions: These findings suggest that cryopreserved hepatocyte s represent an appropriate source of cells for therapeutic hepatocyte trans plantation.