Oxidative Stress in Myocardial Remodeling and Failure

描述（申请人逐字描述）：活性氧 (ROS)在心肌中增加与向左进展一致 心室（LV）收缩衰竭。在体外培养的心肌细胞中，我们发现 ROS可以模拟心肌重塑中观察到的细胞事件， 肾上腺素能刺激的肥大和凋亡作用， 机械应变依赖于ROS。我们将使用体外、体内 体内和离体方法来测试我们的中心假设，即ROS发挥作用， 在介导过度肾上腺素能刺激的作用中起关键作用， 机械负荷对心肌表型的影响。我们将使用成年大鼠心室 1）阐明数量和特定类型的作用 ROS（例如，O_2、H_2O_2和OH）介导肾上腺素能神经递质的作用 刺激和机械应变对肌细胞表型的影响，以及2）确定 响应肾上腺素能刺激和机械应变的ROS来源。 在这些体外实验的基础上，我们将测试我们的中心假设， 体内使用转基因小鼠，其表现出凋亡表型， 心肌β 1 AR过度表达或由于 过表达Galphaq，与α 1 AR偶联的主要G蛋白， 机械应变为了检测ROS在介导心肌细胞凋亡中的作用， 在这些模型中，ROS水平将通过杂交育种与 抗氧化酶锰水平升高的小鼠 超氧化物歧化酶（MnSOD）或Cu/ZnSOD。这些主要终点 实验将是改造的基本措施， 功能水平-左心室扩张和收缩功能。二次 终点将是重要的细胞事件， 心肌重构-肥大，胎儿程序表达和凋亡， 心肌细胞和心脏成纤维细胞中金属蛋白酶的活化。 这些实验的解释将通过测量ROS来辅助， 电顺磁共振和细胞的氧化还原状态的比率， 氧化型谷胱甘肽这些研究提供了新的机制 了解心肌重塑的过程。

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.