The Role of Caspases in Warm and Cold Ischemia

移植肾功能延迟恢复（DGF）可独立预测1年和5年肾移植存活率降低， 导致慢性移植物肾病（CAN）的发展。DGF是由寒冷和 热缺血冷缺血发生在搏动机灌注和静态冷藏过程中。 肾脏该基金将重点研究冷缺血和热缺血的病理生理学，特别是 半胱天冬酶。Caspase-3是凋亡和坏死细胞死亡的主要介质。半胱天冬酶-1将前- 炎性细胞因子IL-1 β和IL-18转化为其活性形式。总的假设是半胱天冬酶 介导冷缺血和热缺血中的近端肾小管损伤。在冷缺血模型中， 半胱天冬酶-3对近端肾小管细胞凋亡以及严重的刷状缘损伤的作用将是 评估。caspase-3、7、9的基因表达、蛋白质和活性（细胞凋亡的线粒体途径） 和8（凋亡的死亡受体途径）将在静态和脉动冷期间测定 缺血将对近端小管中的活化半胱天冬酶-3进行免疫组织化学。效果 将评估半胱天冬酶抑制对肾脏形态的影响。这些实验的结果将 有助于了解冷缺血损伤和器官保存。Caspase-1介导 IL-18的产生介导缺血性ARF。IL-18是干扰素γ的有效诱导剂， MHC表达的强力诱导剂。Caspase-1和IL-18介导的干扰素γ增加 将在热休克模型中测定肾中的MHC表达和近端小管上的MHC表达。 缺血将评估肾脏中的干扰素γ和MHC I类和II类mRNA表达。的 将评价胱天蛋白酶-1、IL-18和干扰素γ抑制对MHC表达影响。减少 MHC表达与肾移植免疫原性降低相关，具有重要意义 DGF对短期和长期同种异体移植物功能的有害影响。

Delayed graft function (DGF) independently predicts reduced 1- and 5- year kidney transplant survival and contributes to the development of chronic allograft nephropathy (CAN). DGF is caused by both cold and warm ischemia. Cold ischemia occurs during both pulsatile machine perfusion and static cold storage of kidneys. This grant will focus on the pathophysiology of cold and warm ischemia and specifically the role of caspases. Caspase-3 is a major mediator of apoptotic and necrotic cell death. Caspase-1 converts the pro- inflammatory cytokines IL-1beta and IL-18 to their active forms. The overall hypothesis is that caspases mediate proximal tubular damage in both cold and warm ischemia. In a model of cold ischemia the contribution of caspase-3 to proximal tubular apoptosis as well as severe brush border injury will be assessed. Gene expression, protein and activity of caspases-3, 7, 9 (mitochondrial pathway of apoptosis) and 8 (death receptor pathway of apoptosis) will be determined during both static and pulsatile cold ischemia. Immunohistochemistry for activated caspase-3 in proximal tubules will be performed. The effect of caspase inhibition on kidney morphology will be assessed. The findings of these experiments will contribute to the understanding of cold ischemia injury and organ preservation. Caspase-1-mediated production of IL-18 mediates ischemic ARF. IL-18 is a potent inducer of interferbn gamma, which is a powerful inducer of MHC expression. Caspase-1 and IL-18-mediated increase in interferon gamma expression in the kidney and MHC expression on proximal tubules will be determined in a model of warm ischemia. Interferon gamma and MHC class I and II mRNA expression in the kidney will be assessed. The effect of caspase-1, IL-18 and interferon gamma inhibition on MHC expression will be evaluated. Reduced MHC expression is associated with decreased kidney graft immunogenicity and has important implications for the deleterious effect of DGF on both short and long-term allograft function.