Oxidants and Nitric Oxide in Post-Ischemic Heart Injury

缺血性心脏损伤后的氧化剂和一氧化氮

• 批准号: 7160734
• 负责人: JAY Louis ZWEIER
• 金额: $ 46.43万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7160734
• 关键词: coronary occlusion /thrombosis; disease /disorder model; enzyme structure; heart; inflammation; injury; ischemia; laboratory mouse; laboratory rat; model; myocardial ischemia /hypoxia; nitrates; nitric oxide; nitric oxide synthase; nitrites; oxidative stress; oxidizing agents; proteins; reperfusion; role; transcription factor; vascular endothelium

Oxygen radical generation is increased in the postischemic heart and leads to altered nitric oxide (NO) production and postischemic injury. Using Electron Paramagnetic Resonance (EPR) and other techniques, we directly measured the mechanisms of oxygen radical and NO generation in the postischemic heart. From these and other recent studies, it has been shown that oxidants alter NO generation from nitric oxide synthase (NOS). However, the precise role of oxidants in the regulation of NOS structure and function remains unknown. Recently, it has been shown that under ischemic conditions oxygen radical generating enzymes, such as xanthine oxidase (XO), also form NO through reduction of nitrite or nitrate. However, the nature and role of NOS-independent pathways of NO formation in the modulation of postischemic injury is unclear. Therefore, this project will characterize these processes of NO formation and their oxidant interactions. Studies will be performed first at the enzyme level; then in endothelial cells, followed by studies in isolated heart models and finally in vivo models of coronary occlusion and reflow. This project has the following 5 specific aims. 1) To characterize mechanisms by which 'O2~ and 'O2~ -derived oxidants affect the structure and function of human endothelial NOS (eNOS). 2) To determine the mechanism by which -O2" and 'O2 -derived oxidants alter eNOS structure and function in the isolated postischemic heart and evaluate approaches to restore eNOS function. 3) To characterize fundamental mechanisms of nitrite, nitrate or organic nitrate mediated NO generation. 4) To characterize the role of nitrite or nitrate mediated pathways of NO generation in the isolated postischemic heart and the mechanisms that regulate this process. 5) In vivo testing and EPR/NMR coimaging of novel therapeutics to inhibit oxidant injury, restore NOS function and confer myocardial protection. For these aims; EPR, electrochemical, and chemiluminescence measurements of oxygen radicals, NO, and NO derived species will be performed along with characterization of the function, structure and modification of the critical NO generating enzymes. Overall, this project will determine the interactions between oxygen radicals and the pathways of NO generation that occur in the process of postischemic injury, and lead to the development of optimal strategies to salvage heart muscle at risk.

缺血后心脏中氧自由基的产生增加，导致一氧化氮 (NO) 发生变化 生产和缺血后损伤。使用电子顺磁共振（EPR）和其他技术， 我们直接测量了缺血后心脏中氧自由基和NO生成的机制。 这些和其他最近的研究表明，氧化剂会改变一氧化氮生成一氧化氮的过程 合酶（NOS）。然而，氧化剂在 NOS 结构和功能调节中的精确作用 仍然未知。最近，有研究表明，在缺血条件下，氧自由基产生 黄嘌呤氧化酶 (XO) 等酶也可通过还原亚硝酸盐或硝酸盐形成 NO。然而， 不依赖 NOS 的 NO 形成途径在调节缺血后损伤中的性质和作用是 不清楚。因此，本项目将表征 NO 形成及其氧化剂的这些过程 互动。首先将在酶水平进行研究；然后在内皮细胞中，然后是 研究离体心脏模型，最后研究冠状动脉闭塞和回流的体内模型。这个项目 有以下5个具体目标。 1) 表征“O2~”和“O2~”衍生氧化剂的产生机制 影响人内皮型一氧化氮合酶（eNOS）的结构和功能。 2) 确定机理 其中-O2”和'O2衍生的氧化剂改变离体缺血后心脏中的eNOS结构和功能 并评估恢复 eNOS 功能的方法。 3) 表征亚硝酸盐的基本机制， 硝酸盐或有机硝酸盐介导的NO生成。 4) 表征亚硝酸盐或硝酸盐介导的作用 离体缺血后心脏中 NO 生成途径及其调节机制 过程。 5) 抑制氧化损伤、恢复功能的新型疗法的体内测试和 EPR/NMR 联合成像 NOS 功能并赋予心肌保护作用。为了这些目标； EPR、电化学和 将进行氧自由基、NO 和 NO 衍生物质的化学发光测量 以及关键 NO 生成的功能、结构和修饰的表征 酶。总体而言，该项目将确定氧自由基与途径之间的相互作用 缺血后损伤过程中发生NO生成，并导致最佳状态的发展 挽救处于危险中的心肌的策略。