Right Ventricular Dysfunction After Pressure Overload

压力过载后右心室功能障碍

• 批准号: 6765893
• 负责人: CLIFFORD RUSSELL GREYSON
• 金额: $ 31.24万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6765893
• 关键词: SDS polyacrylamide gel electrophoresis; adenosinetriphosphatase; biopsy; calpain; chemical fingerprinting; cytoskeletal proteins; enzyme activity; enzyme inhibitors; extracellular matrix proteins; heart contraction; heart disorder; heart function; heart ventricle; intracardiac pressure; mass spectrometry; matrix assisted laser desorption ionization; metalloendopeptidases; myofibrils; protein degradation; protein quantitation /detection; protein structure; proteomics; statistics /biometry; swine; western blottings

DESCRIPTION (provided by applicant): Right ventricular (RV) contractile failure from acute RV pressure overload is an important cause of morbidity and mortality in conditions such as massive pulmonary embolism, hypoxic pulmonary vasoconstriction, and following cardiopulmonary bypass and cardiac transplantation. The applicant previously demonstrated that intrinsic RV contractile function is depressed following a brief period of pressure overload, even after restoration of normal loading conditions. The overall purpose of the proposed research is to determine the mechanism of impaired RV contractile function following acute RV pressure overload. RV dysfunction following pressure overload is qualitatively similar to left ventricular stunning after ischemia-reperfusion, and to skeletal muscle dysfunction after strenuous exercise; these have been hypothesized to result from proteolysis of myofibrillar or cytoskeletal proteins by the calcium-sensitive cysteine protease calpain, or from degradation of the extracellular collagen matrix. Therefore, we plan to test the following hypotheses: #1. RV dysfunction from acute RV pressure overload is associated with and temporally related to proteolytic degradation of myofibrillar proteins, cytoskeletal proteins, and/or the extracellular collagen matrix (ECM). #2. Such proteolytic degradation is manifested by alterations in myofibrillar ATPase activity, disruption of myocardial sarcomere architecture, and or morphologic alterations in the extracellular collagen weave. #3. Degradation of myofibrillar proteins, cytoskeletal proteins, and or the ECM is caused by stress-related activation of calpain and/or of matrix metalloproteinases (MMPs). We plan to determine whether calpain and/or MMPs are activated during acute RV pressure overload, and whether RV dysfunction following acute RV pressure overload can be prevented by specific inhibitors of calpain or MMPs; use 1D and 2D polyacrylamide gel electrophoresis (PAGE), Western blotting and mass spectrometry/peptide fingerprinting to determine the time course of degradation and/or phosphorylation of major myofibrillar and cytoskeletal proteins during acute RV pressure overload; measure changes in RV myofibrillar ATPase activity; and assess myocardial ultrastructure following acute pressure overload. Even if the hypothesized mechanism is not confirmed, the methods employed (so-called proteomics) are likely to identify other potential mechanisms of RV contractile dysfunction, and will contribute to the development of a more complete 2D-PAGE map of porcine myocardial proteins.

描述(由申请人提供)：急性右室压力超负荷导致的右室收缩衰竭是大面积肺栓塞、缺氧性肺血管收缩以及体外循环和心脏移植术后发病率和死亡率的重要原因。申请人先前证明，在短暂的压力过载后，即使在恢复正常负荷条件后，固有的右室收缩功能也会受到抑制。本研究的总体目的是确定急性RV压力超负荷后RV收缩功能受损的机制。 压力超负荷后的RV功能障碍定性上类似于缺血-再灌注后的左心室顿抑，以及剧烈运动后的骨骼肌功能障碍；这些都被认为是由于钙敏感的半胱氨酸蛋白酶Calain对肌原纤维或细胞骨架蛋白的蛋白分解，或者是由于细胞外胶原基质的降解。因此，我们计划检验以下假设： #1.急性右室压力超负荷所致的右室功能障碍与肌原纤维蛋白、细胞骨架蛋白和/或细胞外胶原基质(ECM)的蛋白降解有关，且在时间上与此相关。 这种蛋白降解表现为肌原纤维ATPase活性的改变，心肌肌节结构的破坏，和/或细胞外胶原编织的形态改变。 #3.肌原纤维蛋白、细胞骨架蛋白和或细胞外基质的降解是由钙蛋白和/或基质金属蛋白酶(MMPs)的应激激活引起的。 我们计划确定在急性右室压力超负荷期间是否激活了Calain和/或MMPs，以及特定的钙蛋白酶或MMPs抑制剂是否可以预防急性右室压力超负荷后的右室功能障碍；使用一维和二维聚丙烯酰胺凝胶电泳(PAGE)、Western blotting和质谱仪/肽指纹图谱来确定急性右室压力超负荷时主要肌纤维和细胞骨架蛋白的降解和/或磷酸化的时间历程；测量右室肌纤维ATPase活性的变化；以及评估急性右室压力超负荷后心肌的超微结构。 即使假设的机制没有得到证实，所采用的方法(所谓的蛋白质组学)也可能确定RV收缩功能障碍的其他潜在机制，并将有助于开发更完整的猪心肌蛋白质2D-PAGE图谱。