Vascularization and Growth of Human Myocardial Grafts

项目1：人体心肌移植物的血管化和生长 该项目的目标是利用心血管发育和干细胞CEU生物学的经验来创造功能心肌。多能的人类干细胞现在可以定向到心肌命运，产生在梗塞中存活的人类心肌细胞，改善心功能，并且应该与宿主在免疫上相容。我们的中心假设是，这些移植物的显著生长和功能需要冠状血管供应的共同发展，并且增强的血管形成将促进肌肉的重新形成。提出了三个具体目标。目的1建立在组织工程学观察的基础上，证明小鼠成纤维细胞和人脐静脉内皮细胞与人心肌细胞合作形成血管化的心肌组织。我们将通过筛选来自hESCs和EPC的MSC克隆和内皮细胞，首先在心脏组织工程中，然后在梗死心脏中，鉴定临床上相关的间充质细胞和内皮细胞的来源。目的2探讨人胚胎干细胞来源的新型心血管祖细胞在心脏修复中的适用性。这种多能的中胚层前体细胞是通过KDR(VEGFR2)的表达来鉴定的，能够产生人的心肌细胞、内皮细胞和平滑肌细胞。我们将测试KDR-I细胞形成人类心肌和人类冠脉循环的能力，我们预测，与仅有心肌细胞相比，这将增加梗死心脏的心肌移植物大小、心肌血流量和收缩功能。目的3研究心脏移植物诱导宿主冠脉侧支动脉形成的机制，探讨Hedgehog信号和单核细胞在促进动脉化中的作用。这些实验解决了有关心脏修复机制的关键问题，并首次系统地研究了结合新心肌形成人类冠状循环的问题。

Project 1: Vascularization and Growth of Human Myocardial Grafts The goal of this project is to use lessons from cardiovascular development and stem ceU biology to create functional myocardium. Pluripotent human stem cells can now be directed to myocardial fates, yielding human myocardial cells that survive in the infarct, improve cardiac function and should be immunologically compatible with the host. Our central hypothesis is that significant growth and function of these grafts requires co-development of a coronary vascular supply, and that augmented vascularization will promote remuscularization. Three specific aims are proposed. Aim 1 builds on observations from tissue engineering, demonstrating that mouse fibroblasts and HUVECs cooperate with human cardiomyocytes in the formation of vascularized myocardial tissue. We will identify clinically relevant sources of mesenchymal cells and endothelium by screening MSC clones and endothelium derived from hESCs and EPCs, first in a cardiac tissue engineering and then in infarcted hearts. Aim 2 explores the suitability of a novel cardiovascular progenitor cell derived from hESCs for cardiac repair. This multipotent mesodermal progenitor is identified by expression of KDR (VEGFR2) and is capable of generating human cardiomyocytes, endothelium and smooth muscle cells. We will test the ability of KDR-i- cells to form human myocardium and a human coronary circulation, which we predict will enhance myocardial graft size, myocardial blood flow and contractile function in the infarcted heart when compared to cardiomyocytes-only. Aim 3 will investigate the mechanism through which cardiac grafts induce formation of collateral arteries from host coronaries, exploring the role of hedgehog signaling and the monocyte in promoting arterialization. These experiments address key questions regarding mechanisms of cardiac repair and are the first to systematically address formation of a human coronary circulation in combination with new myocardium.