Flow-Mediated Dilation of Human Coronary Arterioles

人冠状动脉的血流介导扩张

• 批准号: 7038684
• 负责人: David D. Gutterman
• 金额: $ 37.88万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7038684
• 关键词: antifungal antibiotics; antioxidants; arterioles; biological signal transduction; cellular respiration; clinical research; coronary vessels; cytoskeletal proteins; free radical oxygen; hemodynamics; human tissue; hydrogen peroxide; mitochondria; nitric oxide; shear stress; small interfering RNA; tissue /cell culture; tumor necrosis factor alpha; vascular endothelium; vasodilation; vasodilators

DESCRIPTION (provided by applicant): Shear stress acting on endothelial cells produces vasodilation. This is arguably the most physiologically important endothelial mechanism of dilation and occurs in virtually every vascular bed. Recent data from our laboratory indicate that flow-mediated dilation (FMD) occurs in coronary arterioles from patients with coronary disease however it operates through a novel mechanism involving endothelial production of reactive oxygen species (ROS) including hydrogen peroxide (H2O2). Surprisingly the mitochondrial respiratory chain plays a necessary role in FMD in the human heart, however it is not known how mitochondria are involved in the transduction of mechanical shear stress on the surface of the endothelium to elicit dilation. Our overall hypothesis is that shear acting on endothelial cells through attached cytoskeletal elements stimulates release from the mitochondria of H2O2, an endothelial derived hyperpolarizing factor (EDHF). We shall test this hypothesis in three ways. First antimycin A and TNFalpha will be used to determine if pharmacological stimulation of mitochondrial ROS release can elicit dilation of human coronary arterioles. In separate studies, we shall use novel antioxidants targeted to the mitochondrial inner membrane to determine whether H2O2 generated from within the mitochondria is necessary for FMD. A bioassay system will confirm whether H2O2 is indeed an EDHF mediating FMD in the human coronary circulation. Second we will use immunohistochemistry and specific pharmacological and molecular approaches including siRNA to determine whether endothelial cytoskeletal elements play a necessary role in FMD and mitochondrial ROS generation. Third, we shall test the hypothesis that nitric oxide through its inhibitory effect on mitochondrial respiration reduces FMD in the human heart. This will be done using nitric oxide donors, measuring mitochondrial complex activity and ROS generation. These experiments may identify a pathway not previously described by which nitric oxide can inhibit EDHF-mediated dilation; namely, by blocking mitochondrial production of ROS. Collectively these aims address a novel mechanism of endothelium-dependent vasodilation involving mitochondrial generation of ROS, thus far reported only in human hearts. These studies should identify new links among cell processes including mechanotransduction, respiration, and redox signaling that regulate physiological events such as vasodilation.

描述（由申请人提供）：作用于内皮细胞的剪切应力产生血管舒张。这可以说是生理上最重要的内皮扩张机制，几乎发生在每个血管床中。我们实验室的最新数据表明，冠状动脉疾病患者的冠状动脉中发生血流介导的扩张 (FMD)，但它通过一种涉及内皮产生包括过氧化氢 (H2O2) 在内的活性氧 (ROS) 的新机制发挥作用。令人惊讶的是，线粒体呼吸链在人类心脏的 FMD 中发挥着必要的作用，但目前尚不清楚线粒体如何参与内皮表面机械剪切应力的转导以引起扩张。我们的总体假设是，通过附着的细胞骨架元件作用于内皮细胞的剪切力刺激线粒体释放 H2O2，这是一种内皮衍生的超极化因子 (EDHF)。我们将以三种方式检验这个假设。首先，抗霉素 A 和 TNFα 将用于确定线粒体 ROS 释放的药理学刺激是否可以引起人冠状动脉扩张。在单独的研究中，我们将使用针对线粒体内膜的新型抗氧化剂来确定线粒体内产生的 H2O2 是否是 FMD 所必需的。生物测定系统将确认 H2O2 是否确实是人体冠状循环中介导 FMD 的 EDHF。其次，我们将使用免疫组织化学以及包括 siRNA 在内的特定药理学和分子方法来确定内皮细胞骨架元件是否在 FMD 和线粒体 ROS 生成中发挥必要的作用。第三，我们将检验这样的假设：一氧化氮通过其对线粒体呼吸的抑制作用减少人类心脏中的FMD。这将使用一氧化氮供体来完成，测量线粒体复合物活性和 ROS 生成。这些实验可能确定了一条先前未描述过的途径，一氧化氮可以通过该途径抑制 EDHF 介导的扩张；即，通过阻断线粒体产生 ROS。总的来说，这些目标解决了一种涉及线粒体生成 ROS 的内皮依赖性血管舒张的新机制，迄今为止仅在人类心脏中进行了报道。这些研究应该确定细胞过程之间的新联系，包括调节血管舒张等生理事件的机械转导、呼吸和氧化还原信号传导。