Transplantation of Reduced-Size Fatty Livers

缩小脂肪肝移植

基本信息

批准号：
7103971
负责人：
ZHI ZHONG
金额：
$ 26.94万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-06-01 至 2011-05-31
项目状态：
已结题

项目摘要

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.

描述（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。这些研究旨在阐明机制并制定防止部分脂肪移植失败的策略。我们将使用缩小尺寸的大鼠肝移植来测试脂肪变性和部分肝移植协同增加活性氧和氮（ROS和RNS）、抑制线粒体功能并抑制肝再生的独特假设。在目标 1 中，我们将研究脂肪变性是否会增加部分肝移植后的移植失败。高脂肪饮食和缺乏胆碱饮食会分别诱发脂肪肝，并缩小至原来大小的30%至50%。我们将评估移植后的存活率、肝功能和组织学，作为脂肪变性、移植物体积和冷藏时间的函数。在目标 2 中，我们将检验以下假设：高脂肪饮食诱导的脂肪部分移植物中 ROS 和 RNS 增加，从而导致损伤。 ROS 将通过自旋捕获技术和 4-羟基壬烯醛的免疫组织化学测定，RNS 将评估硝基酪氨酸和亚硝酸盐/硝酸盐水平。我们预计脂肪部分移植物中的 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来识别 ROS 和 RNS 的细胞来源。将评估抗氧化剂（Ad-超氧化物歧化酶、N-乙酰半胱氨酸和多酚）和抗硝疗法（一氧化氮合酶抑制剂）对脂肪部分移植物的存活和损伤的影响。在目标 3 中，将评估脂肪变性和移植物体积对能量供应的影响。将确定解偶联蛋白 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以及抗氧化剂和抗硝化疗法对线粒体功能的影响。在目标 4 中，将评估脂肪变性和移植物体积对肝再生的影响。将评估细胞增殖和再生调节因子（细胞因子、转录因子、生长因子和细胞周期相关基因）。此外，我们将研究保护线粒体功能以及抗氧化和抗硝疗法是否可以改善肝再生。总而言之，我们期望这项工作将为减少脂肪移植失败的机制提供根本性的新见解，并制定基于机制的策略，以增加脂肪肝在临床上部分肝移植的使用并改善其结果。