トランスジェニックマウスを用いた肝臓切除におけるエネルギー代謝の研究-遺伝子治療の肝臓外科への導入

肌酸激酶对肌酸/磷酸肌酸系统的催化作用在肝脏中不表达。1994年和1995年分别用表达肌酸激酶的转基因小鼠肝脏研究了肝切除术后肝脏再生的促进作用和内毒素耐受的诱导作用。在肝脏中添加磷酸肌酸的情况下，肝脏再生过程中ATP的减少受到抑制，线粒体内ATP维持在较高水平。因此，线粒体氧化磷酸化增强，导致肝脏重量快速恢复和DNA合成加速。在内毒素给药的第二项研究中，磷酸肌酸的存在导致炎症细胞因子反应的衰减，抑制肝脏活性氧的产生，下调ICAM-1，导致内毒素的致死作用降低。这些结果表明，肝脏转染肌酸激酶基因对手术应激引起的肝衰竭有预防作用。在第三项研究中，利用转基因小鼠肝脏分离的肝细胞，在培养基中添加肌酸可以防止氨负荷攻毒导致肝细胞ATP水平下降。在半乳糖胺联合内毒素的暴发性肝炎模型的第四项研究中，磷酸肌酸的存在抑制出血性坏死伴细胞凋亡。总之，将肌酸激酶基因转染到肝脏中为肝衰竭提供了一种可能的治疗方法。

The catalysis of creatine/phsophocreatine system by creatine kinase is not expressed in the liver. Promoting effect of liver regeneration after hepatectomy and induction of endotoxin tolerance were studied using transgenic mouse liver expressing creatine kinase in 1994 and 1995, respectively. In the presence of phosphocreatine in the liver by feeding creatine, decrease in ATP accompanied with liver regeneration was inhibited, and intramitochondrial ATP was maintained at high level. Consequently, mitochondrial oxidative phosphorylation was enhanced, resulting in rapid recovery of liver weight and acceleration of DNA synthesis. In the second study of endotoxin administration, the presence of phosphocreatine caused attenuation of inflamatory cytokine response, inhibition of generation of reactive oxygen species in the liver, down-regulation of ICAM-1, resulting in decrease in lethal effect of endotoxin. These results indicate that transfection of creatine kinase gene into the liver has a prophylactic effect for liver failure induced by surgical stresses. In the third study using isolated hepatocyte from the transgenic mouse liver, addition of creatine into the culture medium prevented decrease in hepatocellular ATP level by challenge with ammonium load. In the fourth study of fulminant hepatitis model using combination of galactosamine and endotoxin, the presence of phosphocreatine inhibited hemorrhagic necrosis with apoptosis. In summary, transfection of creatine kinase gene into the liver provides a possible treatment for liver failure.