Oxidative Stress in Myocardial Remodeling and Failure

描述(申请人的逐字描述)：活性氧物种 (ROS)在心肌中的增加与向左进展一致 室性(LV)收缩功能衰竭。在体外培养的心肌细胞中，我们发现 ROS可以模拟在心肌重塑中观察到的细胞事件，以及 肾上腺素能刺激和细胞凋亡的肥大和凋亡效应 机械应变与ROS有关。我们将使用体外和体内的组合 体内和体外方法来验证我们的中心假设，即ROS发挥着 在调节过度肾上腺素能刺激的影响中的关键作用 机械过载对心肌表型的影响。我们将使用成年大鼠的脑室 体外培养的心肌细胞1)阐明其数量和具体类型的作用 ROS(如O2、H_2O_2和OH)在介导肾上腺素能作用中的作用 刺激和机械应变对心肌细胞表型的影响；2)测定 对肾上腺素能刺激和机械应变作出反应的ROS来源。 在这些体外实验的基础上，我们将在 使用转基因小鼠活体，该转基因小鼠由于 心肌β1受体过度表达或肥大表型 Alpha1AR和Alpha1AR偶联的主要G蛋白Galphaq的过表达 机械拉力。检测ROS在心肌损伤中的调节作用 在这些模型中，ROS水平将通过与 表现出抗氧化酶锰水平升高的小鼠 超氧化物歧化酶(MnSOD)或铜/锌超氧化物歧化酶。这些产品的主要终端 实验将是重塑结构和结构的根本措施 功能水平--LV腔扩张和收缩功能。次要的 终端将是重要的蜂窝事件，已牵涉到 心肌重构-肥大、胎儿程序表达与细胞凋亡 心肌细胞和心脏成纤维细胞中金属蛋白酶的激活。 对这些实验的解释将得到ROS测量的帮助 电顺磁共振与细胞氧化还原态的还原比 氧化的谷胱甘肽。这些研究提供了新的机制 对心肌重塑过程的理解。

DESCRIPTION (the applicant's description verbatim): Reactive oxygen species (ROS) are increased in the myocardium coincident with the progression to left ventricular (LV) systolic failure. In cardiac myocytes in vitro, we have found that ROS can mimic the cellular events observed in myocardial remodeling, and that the hypertrophic and apoptotic effects of adrenergic stimulation and mechanical strain are ROS-dependent. We will use a combination of in vitro, in vivo and ex vivo methods to test our central hypothesis that ROS play a critical role in mediating the effects of excessive adrenergic stimulation and mechanical overload on myocardial phenotype. We will use adult rat ventricular myocytes in vitro 1) to elucidate the roles of the quantity and specific types of ROS (e.g., O2, H2O2 and OH) in mediating the effects of adrenergic stimulation and mechanical strain on myocyte phenotype, and 2) to determine the source of ROS in response to adrenergic stimulation and mechanical strain. Building on these in vitro experiments, we will test our central hypothesis in vivo using transgenic mice that exhibit an apoptotic phenotype due to myocardial overexpression of beta1AR or a hypertrophic phenotype due to overexpression of Galphaq, the primary G protein coupled to alpha1AR and mechanical strain. To test the role of ROS in mediating the myocardial phenotypes in these models, ROS levels will be decreased by cross-breeding with mice that express increased levels of the antioxidant enzymes manganese superoxide dismutase (MnSOD) or Cu/ZnSOD. The primary endpoints for these experiments will be fundamental measures of remodeling at the structural and functional level - LV chamber dilation and contractile function. Secondary endpoints will be important cellular events that have been implicated in myocardial remodeling - hypertrophy, fetal program expression and apoptosis in cardiac myocytes, and activation of metalloproteinases in cardiac fibroblasts. The interpretation of these experiments will be aided by measurement of ROS by electroparamagnetic resonance and cellular redox state by the ratio of reduced to oxidized glutathione. These studies offer to provide new mechanistic understanding of the process of myocardial remodeling.