The effect of hepatocyte growth factor on the initiation phase of liver regeneration after cold ischemia in a rat model of small-for-size liver transplantation.

BACKGROUND/AIMS: In this study, adenovirus carrying human HGF gene (Ad-HGF) was administered to investigate whether hepatocyte growth factor (HGF) can restore liver regeneration after prolonged cold ischemia, especially during the initiation phase, in a rat model of small-for-size liver transplantation. METHODOLOGY: A rat model was established using 30% small-for-size liver grafts. Before hand, the grafts were preserved at 4°C for 45min, 2h, 6h and 10h in UW solution. A recombinant adenoviral vector carrying HGF and Ad-HGF or adenovirus encoding enhanced green fluorescent protein (Ad-EGFP) was administered to the 10h group. Survival rates, serum levels of alanine aminotransferase, recovery of the graft weight, hepatic architecture, proliferating cell nuclear antigen (PCNA), cell signaling pathways and several immediate early genes (e.g. jun-B, c-fos) were assessed. RESULTS: Injury to the grafts and extent of inflammation of the small grafts increased due to prolonged cold ischemia, while the number of PCNA- positive hepatocytes decreased and liver regeneration mechanism was affected. These factors resulted in low levels of interleukin (IL)-6, tumor necrosis factor receptor (TNFR)- α , and phosphorylated signal transducer and activator of transcription 3 (p-Stat3) in liver tissue. Ad-HGF administration markedly improved the survival rate, but it did not significantly affect the other parameters. CONCLUSIONS: Prolonged cold ischemia significantly impaired the regenerative ability of small grafts. Ad-HGF promoted liver regeneration but had no observable effect on the initiation phase of liver regeneration.

Adenoviral cardiotrophin-1 transfer improves survival and early graft function after ischemia and reperfusion in rat small-for-size liver transplantation model.

This study was to investigate the effect of donor liver adenoviral cardiotrophin-1 (CT-1) gene transfer on early graft survival and function in rat small-for-size liver transplantation. We constructed a recombinant murine CT-1 adenoviral vector. Donor rats were transduced in vivo with adenoviruses expressing CT-1 (AdCT-1) or control vector (AdEGFP). Livers were harvested 4 days later, reduced to 40% of weight, and transplanted. A syngeneic rat orthotopic liver transplantation model was performed using 40% small-for-size grafts. Graft survival, liver function, hepatic architecture change, the degree of necrosis and apoptosis, and cell survival signaling pathways were assessed. AdCT-1 pretreatment markedly improved liver function and the survival of small-for-size grafts. In the CT-1 treatment group, hepatic architecture was well protected, apoptotic and necrotic cells were reduced; anti-apoptotic protein bcl-2 was up-regulated and pro-apoptotic cleaved caspase-3 was down-regulated, cell survival signaling pathways were activated by phosphorylation of protein kinase B (Akt), extracellular-regulated kinase (ERK) and Signal transducer and activator of transcription-3 (Stat-3) after transplantation. In conclusion, donor liver adenoviral CT-1 transfer ameliorated ischemia/reperfusion injury by decreasing hepatic necrosis and apoptosis in small-for-size liver transplantation, mediated in part by activation of the Akt, ERK, and Stat-3 survival signaling pathways. These results may provide a potential clinical strategy to improve the outcome of small-for-size liver grafts.