Cellular Mechanisms of Cardiac ECM Structure and Function

心脏 ECM 结构和功能的细胞机制

• 批准号: 10585689
• 负责人: Amy D Bradshaw
• 金额: --
• 依托单位: RALPH H JOHNSON VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-01 至 2026-10-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10585689
• 关键词: Ablation; Address; Age; Animal Model; Aortic Valve Stenosis; Cardiac; Characteristics; Chronic; Clinical; Collagen; Congestive Heart Failure; Data; Deposition; Development; Disease Pathway; Excision; Exhibits; Exposure to; Extracellular Matrix; Fibroblasts; Fibrosis; Healthcare; Heart; Homeostasis; Hypertension; Imaging Techniques; In Vitro; Incidence; Lead; Macrophage; Matrix Metalloproteinases; Measurement; Measures; Mediating; Methods; Modification; Molecular; Mus; Myocardial; Myocardium; Outcome; Patient Care; Patients; Peptide Hydrolases; Phenotype; Physiological; Population; Production; Proteins; Publishing; Reproducibility; Research; Role; Structure; System; Testing; Time; Tissue Inhibitor of Metalloproteinase-1; Transgenic Mice; Veterans; aorta constriction; cardiovascular health; clinically relevant; coronary fibrosis; disease diagnosis; hemodynamics; improved; in vivo; innovation; interstitial; mouse model; novel; pressure; profibrotic fibroblast; programs; response; success

Chronic heart failure (CHF) has a designated Quality Enhancement Research Initiative (QUERI) in the VA system to address ways to improve cardiovascular healthcare for Veteran’s suffering from CHF. Success in treatment of CHF associated with chronic pressure overload (hypertension, aortic valve stenosis) is limited by the presence of persistent interstitial fibrosis despite our ability to normalize hemodynamic load. The proposed studies will define abnormalities in cellular mechanisms that cause this critical clinical unmet need. Filling this need will depend on defining the fundamental causal determinants that control both initial ECM degradation and persistence of interstitial myocardial fibrosis following normalization of hemodynamic load. Primary cellular regulators of ECM homeostasis are postulated to be myocardial macrophages and fibroblasts. Our previous studies and preliminary data have led to our central hypothesis: Chronic hemodynamic overload causes fundamental changes in both macrophage and fibroblast phenotype, the hallmark of which is dysregulated protease homeostasis that in turn impedes cellular response to unloading and limits complete regression of fibrosis even after normalization of hemodynamic load. To test this hypothesis, innovations in in vivo animal models and in vitro fibroblast culture were developed. In vivo, a clinically relevant reversal of LVPO (unloading) was created in mice by surgical removal of the transverse aortic constriction (unTAC). UnTAC was found to initiate but lead to an incomplete regression of cardiac fibrosis. Preliminary data indicate that a significant increase in myocardial macrophages coincides with initiation of collagen degradation following hemodynamic unloading but these increases in macrophages are not sustained at later times after unTAC. To address whether load-dependent changes in fibroblast phenotype were a key factor in this remodeling, a fibroblast culture systems that mimics clinically relevant myocardial stiffness was established. In vivo, measurements of myocardial stiffness demonstrated that fibroblasts are exposed to a force of ~8 kPA in PO myocardium and ~2 kPA in normal myocardium. Physiologically relevant, stiffness-dependent changes in fibroblasts phenotype were observed in fibroblasts from normal myocardium whereas fibroblasts from TAC and unTAC myocardium exhibited a pro-fibrotic non-responsive phenotype to changes in stiffness. Preliminary data indicate that Tissue inhibitor of metalloproteinase (TIMP)-1 was a causal factor in this pro-fibrotic persistent phenotype. Our strong preliminary data gave rise to the following Specific Aims to test our central hypothesis: Aim 1: Test the hypothesis that reversal of sustained hemodynamic overload shifts myocardial macrophage phenotype to a distinct but transient anti-fibrotic (ECM-degradation) phenotype that initiates, but does not complete, a load-dependent regression of accumulated interstitial ECM. Aim 2: Test the hypothesis that sustained in vivo increases in hemodynamic load change myocardial fibroblasts to a profibrotic, TIMP-1 dependent phenotype that remains profibrotic even when hemodynamic load is reversed.

慢性心力衰竭（CHF）在VA中具有指定的质量增强研究计划（QUERI） 解决退伍军人患有瑞士法郎的心血管医疗保健方法的系统。成功 与慢性压力超负荷相关的CHF治疗（高血压，主动脉瓣狭窄）受到限制 持续的间质纤维化目的地的存在我们使血液动力学负荷正常化的能力。 提出的研究将定义导致这种关键临床未满足需求的细胞机制异常。 满足这种需求将取决于定义控制两个初始ECM的基本因果决定素 血液动力学负荷归一化后，间质性心肌纤维化的降解和持久性。 ECM稳态的主要细胞调节剂被发布为心肌巨噬细胞和成纤维细胞。 我们以前的研究和初步数据导致了我们的中心假设：慢性血流动力学 超负荷会导致巨噬细胞和成纤维细胞表型的根本变化，其标志是 失调的蛋白酶体内稳态反过来又阻碍了细胞对卸载的反应，并且限制完成 即使在血液动力学负荷归一化之后，纤维化的消退也是如此。为了检验这一假设，创新 开发了体内动物模型和体外成纤维细胞培养。体内，LVPO的临床相关逆转 （卸载）是通过手术去除横向主动脉收缩（UNTAC）在小鼠中创建的。 UNTAC是 发现启动但导致心脏纤维化的不完全回归。初步数据表明 心肌巨噬细胞的显着增加与胶原蛋白降解之后的降解相吻合 血流动力学卸载，但巨噬细胞的增加在UNTAC之后的后期没有持续。到 解决成纤维细胞表型的负载依赖性变化是否是重塑的关键因素 建立了模仿临床相关的心肌僵硬度的成纤维细胞培养系统。体内， 心肌刚度的测量表明，成纤维细胞暴露于PO中约8 kPa的力 正常心肌中的心肌和约2 kPa。生理上相关的，刚度依赖性的变化 在正常心肌的成纤维细胞中观察到成纤维细胞表型，而TAC和 UNTAC心肌暴露了促纤维性的非反应表型，以变化刚度的变化。初步数据 表明金属蛋白酶（TIMP）-1的组织抑制剂是这种纤维化持续性的因果因素 表型。我们强大的初步数据引起了以下特定目的，以检验我们的中心假设： 目标1：检验以下假设：持续血液动力学超负荷的逆转使心肌移动 巨噬细胞表型，具有独特但短暂的抗纤维化（ECM降解）表型 启动但未完成，是累积间隙ECM的负载依赖性回归。 目标2：检验以下假设，即体内持续增加的血液动力学载荷改变心肌。 成纤维细胞达到纤维化的TIMP-1依赖性表型，即使 血液动力学负荷反转。