Genetic modification of liver grafts with an adenoviral vector encoding the Bcl-2 gene improves organ preservation

Background, Liver function after transplantation is determined by the quali ty of the donor organ and the influences of preservation, flush, and reperf usion injury. In this regard, cell death (apoptosis) plays an important rol e in organ preservation and rejection. Therefore, we examined the possibili ty of genetic modification of the liver graft with a recombinant adenovirus vector encoding the Bcl-2 gene to reduce apoptosis during the preservation time. Methods. Liver grafts from C57B1/6 mice were procured and preserved using s tandard techniques. A replication defective adenovirus vector (Delta E1) co ntaining the human Bcl-2 gene (AdCMVhBcl-2) was developed in our laboratory . An adenovirus vector encoding an irrelevant gene (Escherichia coli beta-g alactosidase) was used as a control. Each mouse received 1x10(9) plaque for ming units administered i,v, 48 hr before the Liver procurement. Analyses o f liver enzyme activities were determined in the preservation solution. Apo ptosis in Liver biopsies was determined by DNA fragmentation with an in sit u histochemical assay. Results. Immunohistochemical analysis and RT-PCR confirmed the expression o f hBcl-2 in the grafts. Grafts from livers expressing hBcl-2 showed signifi cant reduction of the aspartame amino transferase (AST) and lactate dehydro genase (LDH) release compared with grafts from the control groups, After re warming, significant cytoprotection was also observed in grafts from animal s treated with AdCMVhBcl-2, Histological analysis correlated with the hepat ocellular injury determined with transaminases and LDH in the preservation solution, Significant reduction in the number of apoptotic cells was observ ed in grafts expressing hBcl-2, Conclusions. We have demonstrated a novel approach to reducing the preserva tion injury to liver grafts with the human Bcl-2 gene. This approach may al low a longer preservation time, potentially reduce the incidence of primary nonfunction, decrease the immunogenicity of the cold injured organ, and in crease the safer use of "marginal" liver grafts.