CASPASE INHIBITION OF APOPTOSIS, INFANT CARDIAC SURGERY

描述(逐字摘自申请者摘要)：主要限制 先天性心脏病修补术的成功结局是发展 心功能不全。虽然病因无疑是多因素的， 有证据表明，这在很大程度上可能是由于心肌细胞的丧失所致。 由于慢性发紫，长期暴露在异常血流动力学负荷下，以及 心脏手术所需的一次或多次缺血-再灌流。 心肌细胞的死亡可以通过坏死或细胞凋亡来发生。与之形成鲜明对比的是 坏死、凋亡是细胞按特定顺序分解的过程。 由多种基因触发的酶途径， 环境和有毒刺激。最近，人类和动物研究表明 缺氧，缺血-再灌注，异常机械负荷，以及 炎症可导致显著的心肌细胞凋亡。这发生在 心肌缺血、梗死、肥厚和心力衰竭。的作用 接受心脏手术的婴儿中的细胞凋亡尚不清楚。在此基础上 来自我们实验室的信息和初步数据，我们认为心肌细胞 细胞凋亡是正常和肥大婴儿的一个重要问题 手术后心肌缺血再灌流。这种心肌细胞的丧失 会对婴儿的心肌造成特别的伤害，因为负荷 受未来生长和残余血流动力学异常的影响。 因为在这种情况下触发细胞凋亡的途径是多条的，所以我们有 选择将重点放在caspase酶的作用上。半胱氨酸酶是焦点 细胞凋亡的传播点和执行点，并直接负责 对于该过程所需的特定蛋白质的蛋白质水解性切割 发生。在AIM的实验我将是第一个定义哪些半胱氨酸酶是L 表达、激活以及哪些关键的细胞内蛋白因此被切割 手术对正常和肥厚心肌的影响 缺血-再灌流，2)量化发生在 设置，以及3)确定特定的caspase抑制对这些细胞的影响 事件。使用一种新的工作心脏移植模型 肥大的婴儿心脏，AIM II将回答一个关键的问题 重要的是，抑制caspase和细胞凋亡的作用是什么？ 对长期心肌炎症、纤维化和功能恢复的影响？这些 实验将是第一个研究蛋白质的有益和有害作用的实验 心肌缺血再灌注损伤中的细胞凋亡。总体而言，这些研究 将为治疗目标和策略提供有价值的新见解 保护这些患者的心肌功能。结果也可能是 适用于缺血、心肌梗死、心脏病患者 失败了。

DESCRIPTION (Verbatim from Applicant's Abstract): A major limitation to successful outcome of the repair of congenital heart lesions is the development of ventricular dysfunction. While the etiology is undoubtedly multifactorial, evidence suggests that it in large part may be due to myocyte loss resulting from chronic cyanosis, prolonged exposure to abnormal hemodynamic loads, and one or more episodes of ischemia-reperfusion required for cardiac surgery. Death of myocytes can occur by either necrosis or apoptosis. In contrast to necrosis, apoptosis is the orderlv disassemblv of the cell by specific enzymatic pathways that are triggered by a wide variety of genetic, environmental and toxic stimuli. Recently, human and animal studies have shown that hypoxia, ischemia-reperfusion, abnormal mechanical loading, and inflammation can cause significant cardiomyocyte apoptosis. This occurs during myocardial ischemia, infarction, hypertrophy, and heart failure. The role of apoptosis in infants undergoing cardiac surgery is not known. Based upon this information and preliminary data from our laboratory, we believe that myocyte apoptosis is a significant problem in infants with normal and hypertrophied myocardium subjected to surgical ischemia-reperfusion. This loss of myocytes will be particularly injurious to the infant myocardium because of the loads imposed by future growth and residual hemodynamic abnormalities. Because the pathways triggering apoptosis in this setting are multiple, we have chosen to focus on the role of the caspase enzymes. Caspases are the focal point of propagation and execution of apoptosis, and are directly responsible for the proteolytic cleavage of specific proteins required for the process to occur. Experiments in Aim I will be the first to l)define which caspases are expressed, activated, and what key intracellular proteins are thereby cleaved in normal and hypertrophied myocardium exposed to surgical ischemia-repercusion, 2)quantify the amount of apoptosis that occurs in this setting, and 3)determine the effects of specific caspase inhibition on these events. Using a novel working heart transplant model with normal and hypertrophied infant hearts, Aim II will answer a question of critical importance, namely what is the effect of inhibition of caspases and apoptosis on long-term myocardial inflammation, fibrosis, and recovery of function? These experiments will be the first to study the beneficial versus harmful roles of apoptosis in myocardial ischemia-reperfusion injury. Overall, these studies will provide valuable new insights into therapeutic targets and strategies to preserve myocardial function in these patients. The results are also likely to be applicable to patients with ischemia, myocardial infarction, and heart failure.