Transplantation of Reduced-Size Fatty Livers

描述（由申请人提供）：由于担心原发性无功能，脂肪肝很少用于部分肝移植。这些研究是为了阐明机制和制定策略，以防止脂肪部分移植失败。我们将使用缩小的大鼠肝移植来验证脂肪变性和部分肝移植协同增加活性氧和氮（ROS和RNS），抑制线粒体功能和抑制肝脏再生的独特假设。在目的1中，我们将研究脂肪变性是否会增加部分肝移植后移植物衰竭。高脂日粮和缺乏胆碱日粮分别诱发脂肪肝，并使其体积缩小至原来的30% ~ 50%。我们将评估移植后的存活率、肝功能和组织学与脂肪变性、移植物体积和冷藏时间的关系。在Aim 2中，我们将验证高脂肪饮食诱导的脂肪部分移植物中ROS和RNS增加导致损伤的假设。ROS将通过自旋捕获技术和4-羟基壬烯醛的免疫组织化学来确定，RNS将通过硝基酪氨酸和亚硝酸盐/硝酸盐水平来评估。我们预计脂肪部分移植物的ROS和RNS产量将高于瘦肉部分移植物。我们还将使用荧光活体多光子显微镜识别ROS和RNS的细胞来源。我们将评估抗氧化剂（超氧化物歧化酶、n -乙酰半胱氨酸和多酚类）和抗氧化疗法（一氧化氮合酶抑制剂）对脂肪部分移植物存活和损伤的影响。在目的3中，将评估脂肪变性和移植物体积对能量供应的影响。我们将检测解偶联蛋白2、线粒体通透性转变和呼吸链活性，以阐明能量产生缺陷的机制，并评估线粒体通透性转变抑制剂和抗氧化和抗氧化治疗对线粒体功能的影响。在Aim 4中，将评估脂肪变性和移植物体积对肝脏再生的影响。将评估细胞增殖和调节再生的因子（细胞因子、转录因子、生长因子和细胞周期相关基因）。此外，我们将研究线粒体功能保护和抗氧化和抗氧化治疗是否能促进肝脏再生。综上所述，我们期望这项工作将为小尺寸脂肪移植失败的机制提供基本的新见解，并制定基于机制的策略，以增加脂肪肝在临床部分肝移植中的使用和改善结果。

DESCRIPTION (provided by applicant): Fatty livers are rarely used for partial liver transplantation due to the fear of primary non-function. These studies are to elucidate mechanisms and to develop strategies to prevent failure of fatty partial grafts. We will use reduced-size rat liver transplantation to test the unique hypotheses that steatosis and partial liver transplantation synergistically increase reactive oxygen and nitrogen species (ROS and RNS), inhibit mitochondrial function and suppress liver regeneration. In Aim 1, we will investigate if steatosis increases graft failure after partial liver transplantation. Fatty livers will be induced by high fat diet and choline-deficient diet, respectively, and reduced to 30% to 50% of original size. We will assess survival, liver function, and histology after transplantation as a function of steatosis, graft volume and cold storage time. In Aim 2, we will test the hypothesis that ROS and RNS are increased in high-fat diet-induced fatty partial grafts, leading to injury. ROS will be determined by the spin-trapping technique and immunohistochemistry for 4-hydroxynonenal and RNS will be assessed as nitrotyrosine and nitrite/nitrate levels. We expect that ROS and RNS production will be higher in fatty than lean partial grafts. We will also identify cellular sources of ROS and RNS using fluorescent intravital multiphoton microscopy. The effects of antioxidants (Ad-superoxide dismutase, N-acetylcysteine and polyphenols) and antinitrative therapies (nitric oxide synthase inhibitors) on survival and injury of fatty partial grafts will be evaluated. In Aim 3, effects of steatosis and graft volume on energy supply will be evaluated. Uncoupling protein 2, mitochondrial permeability transition and respiratory chain activity will be determined to elucidate the mechanisms of defective energy production, and effects of mitochondrial permeability transition inhibitors and antioxidant and antinitrative therapies on mitochondrial function will be evaluated. In Aim 4, the effects of steatosis and graft volume on liver regeneration will be assessed. Cell proliferation and factors regulating regeneration (cytokines, transcription factors, growth factors, and cell cycle related genes) will be evaluated. In addition, we will investigate if protection of mitochondria function and antioxidative and antinitrative therapies improve liver regeneration. Taken together, we expect that this work will provide fundamental new insights into the mechanisms underlying reduced-size fatty graft failure and develop mechanism-based strategies to increase the use and improve the outcome of fatty livers for partial liver transplantation in the clinic.