Angiogenic tissue engineering to limit post-infarction ventricular remodeling

描述（由申请人提供）：目的和具体目的心肌缺血和梗死导致的不良心室重构和心力衰竭是一个日益普遍的全球健康问题，医学和外科治疗是有限的。我们非常需要创新疗法。本研究旨在研究和开发一种新的急性内源性血管重建疗法，该疗法可上调内皮祖细胞（EPCs）并特异性靶向缺血心肌。这种梗死后血管生成治疗增强心肌微循环将研究三个具体目标：1)内皮祖细胞的动员和靶向化运动，以重建缺血心肌。2)局部心肌生物力学特性的血管生成再造可减轻不良心室重构，改善心功能。3)内源性血运重建治疗的转化临床前大型动物模型试验，利用逐步减少侵入性，临床可用的技术。研究设计与方法：在心肌梗死和心室重构大鼠模型中，用粒细胞巨噬细胞集落刺激因子（GMCSF）刺激骨髓生成EPCs。上调的EPCs将通过直接在心肌内给药有效的EPCs趋化因子基质细胞衍生因子-11 （SDF）靶向缺血性心脏。具体机制将通过体外标记的EPCs以及心外SDF诱饵来阐明。EPCs将用流式细胞术和免疫组织化学进行追踪。血管生成将通过凝集素微血管造影进行量化。微血运重建对缺血心肌收缩力的影响将通过多巴酚丁胺应激超声心动图确定，心肌组织特性将利用原子力显微镜和拉伸强度测量来研究。心室重构和心肌功能将通过超声心动图和腔内压力-容量传导微导管在多个时间点进行评估。我们将利用已建立的绵羊缺血性心力衰竭模型，在临床可翻译的动物模型上研究SDF/GMCSF治疗的疗效。从微创开胸术到Stiletto心内膜注射导管再到经皮冠状动脉内给药，逐步评估侵入性逐渐降低、临床可用的给药技术，以优化细胞因子的递送。

DESCRIPTION (provided by applicant): Objectives and Specific Aims Myocardial ischemia and infarction with resultant adverse ventricular remodeling and heart failure form an increasingly prevalent global health problem for which medical and surgical treatments are limited. Innovative therapies are greatly needed. This proposal seeks to investigate and develop a novel acute endogenous revascularization therapy which upregulates endothelial progenitor cells (EPCs) and specifically targets them to ischemic myocardium. This post- infarction angiogenic therapy to augment myocardial microcirculation will study three specific aims: 1) Mobilization and targeted chemokinesis of EPCs to revascularize ischemic myocardium. 2) Angiogenic reengineering of regional myocardial biomechanical properties to attenuate adverse ventricular remodeling and improve cardiac function. 3) Translational preclinical large animal model testing of endogenous revascularization therapy utilizing progressively less invasive, clinically-available technologies. Research Design and Methods: In a rat model of myocardial infarction and ventricular remodeling, bone marrow production of EPCs will be stimulated with granulocyte macrophage colony stimulating factor (GMCSF). The upregulated EPCs will be targeted to the ischemic heart with direct intramyocardial administration of the potent EPC chemokine stromal cell derived factor-11 (SDF). Specific mechanisms will be elucidated by ex vivo tagged EPCs as well as an extracardiac SDF decoy. EPCs will be tracked with flow cytometry and immunohistochemistry. Angiogenesis will be quantified with lectin microangiography. The impact of microrevascularization on ischemic myocardial contractility will be determined with dobutamine stress echocardiography and myocardial tissue properties will be studied utilizing atomic force microscopy and tensile strength measurements. Ventricular remodeling and myocardial function will be assessed at multiple time points with echocardiography and an intracavitary pressure-volume conductance microcatheter. A well-established ovine model of ischemic heart failure will be utilized to study the efficacy of SDF/GMCSF therapy in a clinically translatable animal model. A stepwise evaluation of progressively less invasive, clinically available delivery technologies, from minimally invasive thoracotomy to Stiletto endocardial injection catheter to percutaneous intracoronary administration, will be undertaken to optimize cytokine delivery. PUBLIC HEALTH RELEVANCE: Heart attack and its complications comprise a global health problem for which there are few highly effective treatments. As an innovative therapy, this proposal seeks to amplify the body's native repair machinery by stimulating vascular progenitor cells in the bone marrow and then specifically directing them to the heart to grow new perfusing blood vessels to the damaged heart muscle and providing a clinically viable treatment for human disease.