Extracellular Matrix in Hypertensive Heart Disease & Transition to Heart Failure

高血压心脏病中的细胞外基质

• 批准号: 8903566
• 负责人: Michael R Zile
• 金额: $ 38.68万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8903566
• 关键词: Biopsy; Cardiac; Chronic; Collagen; Development; EFRAC; Equilibrium; European; Event; Extracellular Matrix; Fibrillar Collagen; Fibroblasts; Functional disorder; Goals; Guidelines; Health; Healthcare; Heart failure; Human; Hypertension; In Vitro; Knock-out; Knockout Mice; Lead; Matrix Metalloproteinase Inhibitor; Matrix Metalloproteinases; Measurement; Measures; Methods; Microdialysis; Microfilaments; Modeling; Molecular; Morbidity - disease rate; Mus; Myocardial; Patients; Peptide Hydrolases; Peptides; Phenotype; Play; Property; Proteins; RNA Interference; Role; Stress; Surgical Models; Tamoxifen; Techniques; Testing; Time; Tissues; Transfection; Transgenic Model; Ventricular Remodeling; base; care burden; clinically relevant; connectin; constriction; effective therapy; hypertensive heart disease; in vivo; indexing; interstitial; mortality; novel; outcome forecast; pressure; prevent

DESCRIPTION (provided by applicant): ABSTRACT The development of myocardial remodeling and abnormal diastolic function is a critical event in patients with hypertensive heart disease (HHD). The mechanisms that contribute to the development of abnormal diastolic function and progression to heart failure with a preserved ejection fraction (HFpEF) are poorly defined. This proposal will examine the causal contribution made by changes in fibrillar collagen. We hypothesized that 1- the stoichiometric balance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMPs (TIMPs) is a primary determinant of diastolic stiffness and collagen content, 2- there is a critical change in this stoichiometric balance in HHD patients that develop HFpEF, 3- HFpEF patients have an increase in TIMP-1 that results in decreased interstitial protease activity, decreased collagen degradation, increased collagen content and increased collagen-dependent stiffness, 4- changes in TIMP-1 and interstitial MMP activity reflect a change in fibroblast function; fibroblasts shift to a more profibrotic phenotype in HHD patients that develop HFpEF, and 5- TIMP-1 deletion will prevent and reverse TIMP-1 dependent effects of pressure overload. We developed novel methods that allow, for the first time, in vivo measurements of aggregate interstitial protease activity (using microdialysis and a quenched fluorogenic peptide substrate) and measurement of collagen-dependent myocardial diastolic stiffness (myocardial stress vs. strain measured in LV biopsies treated with sequential extraction techniques). These methods will be applied to both patients with HHD and novel murine surgical and transgenic models of clinically relevant pressure-overload (transverse aortic constriction in tamoxifen-inducible, fibroblast-specific, TIMP-1 knock-out mice). Specific Aim One: Demonstrate that in patients with hypertensive heart disease, the transition to heart failure is characterized by an increase in TIMP-1 and a decrease in in vivo interstitial protease activation leading to an increase in collagen content and an increase in collagen-dependent stiffness. Specific Aim Two: Demonstrate in vitro, using primary fibroblast cultures, that fundamental changes in cardiac fibroblast function occur in patients with HFpEF that result from a TIMP-1 induced decrease in protease activation and decreased collagen degradation. Specific Aim Three: Determine in vivo whether there is a cause and effect relationship between a change in TIMP-1 expression/abundance, interstitial protease activity, and the development of increased collagen- dependent stiffness in a murine model of pressure-overload induced heart failure.

描述（由申请人提供）： 摘要 心肌重塑和舒张功能异常的发生是高血压性心脏病（HHD）患者的关键事件。导致舒张功能异常和射血分数保留心力衰竭（HFpEF）进展的机制尚不清楚。该提案将研究纤维胶原蛋白变化所造成的因果影响。我们假设 1- 基质金属蛋白酶 (MMP) 和内源性 MMP 组织抑制剂 (TIMP) 之间的化学计量平衡是舒张期硬度和胶原蛋白含量的主要决定因素，2- 在发生 HHD 的患者中，这种化学计量平衡发生了重大变化HFpEF、3- HFpEF 患者 TIMP-1 增加，导致间质蛋白酶活性降低、胶原蛋白降解减少、胶原含量增加和胶原依赖性硬度增加，4-TIMP-1和间质MMP活性的变化反映了成纤维细胞功能的变化；在发生 HHD 的患者中，成纤维细胞转变为更促纤维化的表型 HFpEF 和 5-TIMP-1 缺失将防止和逆转压力过载的 TIMP-1 依赖性影响。我们开发了新方法，首次允许体内测量聚集间质蛋白酶活性（使用微透析和猝灭的荧光肽底物）和测量胶原依赖性心肌舒张硬度（心肌应力与在接受治疗的左心室活检中测量的应变）采用顺序提取技术）。这些方法将应用于 HHD 患者以及临床相关压力超负荷的新型小鼠手术和转基因模型（他莫昔芬诱导的、成纤维细胞特异性的、TIMP-1 敲除小鼠的主动脉横缩）。具体目标一：证明高血压心脏病患者向心力衰竭转变的特点是TIMP-1增加和体内间质蛋白酶活化减少，导致胶原含量增加和胶原依赖性增加刚性。具体目标二：使用原代成纤维细胞培养物在体外证明 HFpEF 患者心脏成纤维细胞功能发生根本性变化，这是由于 TIMP-1 诱导蛋白酶活化减少和胶原蛋白降解减少所致。具体目标三：在体内确定压力超负荷诱发心力衰竭的小鼠模型中 TIMP-1 表达/丰度、间质蛋白酶活性的变化与胶原依赖性僵硬度增加之间是否存在因果关系。