Primate Heart Regeneration

 描述（由申请人提供）：这些研究的长期目标是开发一种可用于人类的心脏再生策略。我们目前的重点是人类多能干细胞，更具体地说，是人类胚胎干细胞衍生的心肌细胞（hESC-CM）。基于15年的细胞培养和小动物工作，我们最近表明，hESC-CM可以以一定的规模和纯度生产，允许在最有可能预测人类反应的动物中进行测试：非人灵长类动物Macaca nemestrina。hESC-CM可以产生平均40%梗死面积的移植物，它们机电耦合，与猕猴心脏同步跳动，并在3个月内成熟到成人大小。这一提议解决了下一级的挑战。目的1是一项关键的疗效研究，将确定hESC-CM是否增强梗塞猕猴心脏的收缩功能。将测试三种剂量的人心肌细胞，并通过MRI确定心室结构和功能。目的2解决了我们最近研究中发现的室性心律失常的起源。除了通过遥测监测心律外，我们还将对植入（3个细胞剂量）和假植入灵长类动物心脏进行连续的基于导管的标测，生成激动标测图，将心律失常分类为折返或异位起搏器所致。程控电刺激将评估诱发心律失常的易感性。结合目标1，这些研究将确定是否有一定剂量的心肌细胞可以增强功能而不发生心律失常。目的3：利用分子成像技术来评估移植物群体动态，跟踪移植后细胞死亡和增殖的波动。我们还讨论了移植物血管化的关键问题，测试移植物诱导宿主冠状动脉重塑的假设，尽管有这种反应，移植物是慢性灌注不足。这些实验将为计划中的心脏修复临床试验提供基础，并提供在人类患者中不可能实现的机制见解。

 DESCRIPTION (provided by applicant): The long term goal of these studies is to develop a heart regeneration strategy that can be translated to humans. Our current focus is in human pluripotent stem cells, and more specifically, in human embryonic stem cell-derived cardiomyocytes (hESC-CMs). Building on 15 years' work in cell culture and small animals, we recently showed that hESC-CMs can be produced at a scale and purity that permit testing in the animal most likely to predict the human response: the non-human primate Macaca nemestrina. The hESC-CMs can generate grafts that average 40% of infarct size, and they electromechanically couple, beat in sync with the macaque heart and mature to adult size by 3 months. This proposal addresses the next-level challenges. Aim 1 is a pivotal efficacy study that will determine if hESC-CMs enhance contractile function in the infarcted macaque heart. Three doses of human cardiomyocytes will be tested, and ventricular structure and function will be determined by MRI. Aim 2 addresses the genesis of ventricular arrhythmias identified in our recent study. In addition to monitoring heart rhythm by telemetry, we will perform serial catheter-based mapping of the engrafted (3 cell doses) and sham-engrafted primate heart, generating activation maps that will classify arrhythmias as resulting from reentry or ectopic pacemakers. Programmed electrical stimulation will assess susceptibility to induced arrhythmias. In combination with Aim 1, these studies will determine if there is a dose of cardiomyocytes that enhances function without arrhythmias. Aim 3 uses molecular imaging techniques to assess graft population dynamics, tracking the waves of cell death and proliferation after transplantation. We also address the key question of graft vascularization, testing the hypothesis that grafts induce host coronary arterial remodeling and that, despite this response, that grafts are chronically underperfused. These experiments will provide the foundation for a planned clinical trial of heart repair and provide mechanistic insights not possible in human patients.