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: 9100853
• 负责人: Michael R Zile
• 金额: $ 37.5万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9100853
• 关键词: Biopsy; Cardiac; Chronic; Collagen; Congestive Heart Failure; 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; mouse model; novel; outcome forecast; pressure; prevent

 DESCRIPTION (provided by applicant): 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）：心肌重塑和舒张功能异常的发展是高血压性心脏病（HHD）患者的关键事件。导致舒张功能异常发展和进展为射血分数保留性心力衰竭（HFpEF）的机制尚不明确。本提案将研究纤维胶原蛋白变化的因果关系。我们假设：1-基质金属蛋白酶（MMP）和MMP的内源性组织抑制剂（TIMP）之间的化学计量平衡是舒张期硬度和胶原含量的主要决定因素，2-在发生HFpEF的HHD患者中，这种化学计量平衡存在关键变化，3- HFpEF患者TIMP-1增加，导致间质蛋白酶活性降低，胶原降解减少，增加的胶原含量和增加的胶原依赖性硬度，4-TIMP-1和间质MMP活性的变化反映成纤维细胞功能的变化;在发展HFpEF的HHD患者中，成纤维细胞转变为更促纤维化的表型，5- TIMP-1缺失将防止和逆转压力超负荷的TIMP-1依赖性作用。我们开发了新的方法，允许，第一次，在体内测量聚合间质蛋白酶活性（使用微透析和淬灭的荧光肽底物）和测量胶原蛋白依赖性心肌舒张刚度（心肌应力与应变测量左心室活检处理的顺序提取技术）。这些方法将应用于HHD患者和临床相关压力超负荷的新型鼠手术和转基因模型（他莫昔芬诱导的成纤维细胞特异性TIMP-1敲除小鼠的横向主动脉收缩）。具体目标一：证明在高血压性心脏病患者中，向心力衰竭转变的特征是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硬度增加。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变化，这是由TIMP-1诱导的蛋白酶活化减少和胶原降解减少所致。具体目标三：在压力超负荷诱导的心力衰竭的鼠模型中，体内确定TIMP-1表达/丰度、间质蛋白酶活性的变化与胶原蛋白依赖性僵硬增加的发展之间是否存在因果关系。