MYOFIBRILLAR PATHOPHYSIOLOGY IN MYOCARDIAL FAILURE

心肌衰竭中的肌纤维病理生理学

• 批准号: 3083380
• 负责人: MATTHEW R WOLFF
• 金额: $ 7.84万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3083380
• 关键词: SDS polyacrylamide gel electrophoresis; adenosinetriphosphatase; cellular pathology; enzyme activity; ferrets; heart contraction; heart failure; heart function; high voltage electrophoresis; molecular pathology; muscle strength; muscle tension; myocardium disorder; myofibrils; phosphorylation; photomicrography; protein isoforms; protein reconstitution; statistics /biometry; ventricular fibrillation

The purpose of this research proposal is to relate the depression of ventricular function in dilated cardiomyopathy to alterations of the mechanical behavior of the cardiac myofibril. Further, we hope to correlate changes in myofibrillar mechanical behavior to alterations of its low-molecular weight components (troponin subunits, myosin light chains and/or C-protein). We will utilize a small animal model of dilated cardiomyopathy produced by chronic rapid pacing. Contractile properties of failing myocardium will be characterized by measuring force-sarcomere- length and force-sarcomere velocity relations over varying levels of activation in isolated living and chemically permeabilized trabeculae, and in chemically skinned single myocytes. Mechanical measurements will be performed using state-of-the art techniques to measure and servo-control sarcomere length. Content and isoform distribution of the protein constituents of the myofibril will be measured in all preparations in which mechanical measurements are made, using SDS-polyacrylamide gel electrophoresis. Phosphorylation status of these proteins will be determined using high- voltage isoelectric focussing. Changes in content, isoform distribution and phosphorylation status of myofibrillar proteins will be related to alterations in mechanical behavior using regression analysis, and will be further explored by repeating mechanical measurements and biochemical analyses after reversal of heart failure (occurring with cessation of rapid pacing). Finally, the relationship between specific low-molecular weight myofibrillar proteins and mechanical alterations in heart failure will be directly tested by extraction of selected proteins from skinned single cardiomyopathic myocytes. If the protein under study mediate changes in contractile properties, subsequent reconstitution of the protein with its equivalent from non-failing myocardium should restore contractile function to control levels. The applicant has prior experience with mechanical studies involving whole hearts and isolated muscles, including studies involving animal models of dilated cardiomyopathy and hypertrophy. The sponsor has extensive experience and expertise in mechanical and biochemical studies of isolated muscle, and has developed many of the isolated, single myocyte techniques and extraction/reconstitution methods described in the research proposal. This proposal represents a novel extension of these powerful techniques to study of cardiac pathophysiology.

这项研究建议的目的是将抑郁症与 扩张型心肌病患者的心功能变化 心肌原纤维的力学行为。此外，我们希望 肌原纤维力学行为改变与肌纤维力学行为改变的相关性 其低分子量组分(肌钙蛋白亚基、肌球蛋白轻 链和/或C蛋白)。我们将利用扩张的小动物模型 慢性快速起搏引起的心肌病。材料的收缩性能 衰竭心肌的特征是测量力-肌节- 不同水平的肌节长度和力-肌节速度关系 在分离的活体和化学渗透性小梁中的激活，以及 在化学剥离的单个肌细胞中。机械测量将是 使用最先进的技术进行测量和伺服控制 肌节长度。 冬虫夏草蛋白质组分的含量及异构体分布 肌原纤维将在所有机械加工的制剂中进行测量 采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法进行测定。 这些蛋白质的磷酸化状态将用高密度的 电压等电聚焦。含量、异构体分布的变化 而肌原纤维蛋白的磷酸化状态将与 使用回归分析改变力学行为，并将 通过重复机械测量和生化来进一步探索 心力衰竭逆转(发生于心力衰竭停止后)的分析 快速起搏)。最后，具体的低分子之间的关系 心力衰竭患者的重量、肌原纤维蛋白和机械改变 将通过从皮肤中提取选定的蛋白质来直接测试 单个心肌病肌细胞。如果研究中的蛋白质在 收缩特性的变化，随后的重建 蛋白质与来自非衰竭心肌的等价物应该会恢复 收缩功能，以控制水平。 申请者有机械研究的经验，涉及整体 心脏和分离的肌肉，包括涉及动物模型的研究 扩张型心肌病和肥大。赞助商有广泛的 在机械和生化研究方面的经验和专业知识 肌肉，并开发了许多分离的、单一的心肌细胞技术 以及研究建议书中描述的提取/重建方法。 这一提议代表了这些强大技术的新扩展，以 心脏病理生理学研究。