Development of a super liver graft resistant to various kinds of injuries by a gene-transfer technique

点击翻译按钮获取中文摘要

This study was conducted to clarify the mechanism of ischemia-reperfusion (I/R) injury or small-for-size graft (SSG) injury, and to create a super liver graft resistant to various kinds of injuries using a gene-transfer technique.(1) Development of gene-transfer technique :Instead of retrovirus vector with critical risk of leukemia (Science 2002), electroporation-mediated gene transfer to cold preserved graft was carried out, using a new instrument designed for a rat liver graft. Using a combined method of electroporation and hydrodynamic (=positive pressure to the portal vein) technique, luciferase-gene expression in the graft after liver transplantation was found to be increased. But a significant graft damage was also observed. A new gene-transfer method using nano-carrier is, therefore, now applied.(2) Liver transplant (LT) model using a small-for-size graft :In a new rat LT model using small-for-size graft (SSG : 30% of whole liver volume), survival of transplanted rats was suggested to prolong either by either creation of partial porto-systemic shunt (splenopexy beneath the skin) or administration of somatostatin analogue having effect of reduced portal pressure. Therefore, excessive portal perfusion of SSG was proved to be a critical cause of SSG injury. A new LT model was, furthermore, completed in mice.(3) Role of Rho-kinage on ischemia-reperfusion injury :Rho-kinase, a molecular substance related to vascular contraction or neutrophil migration, was found to played an important role on I/R injury. Its inhibitor (Fasudil) inhibited cytokine production (TNFa and IL1b) and free radical production in I/R injury. By administration of Fasudil, postoperative elevation of AST and ALT, and necrotic areas in the specimen, were reduced, furthermore, rat's survival rate after LT improved in a 24-hour cold-preserved LT model. Either anti-sense or dominant negative of Rho-kinase gene is now applied to liver graft using a non-viral gene-transfer technique.