Primate Heart Regeneration

 描述(由申请者提供)：这些研究的长期目标是开发一种可以翻译成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，是人类胚胎干细胞来源的心肌细胞(hESC-CMS)。在15年细胞培养和小动物工作的基础上，我们最近证明，hESC-CMS可以在规模和纯度上生产，从而允许在最有可能预测人类反应的动物身上进行测试：非人类灵长类动物猕猴。HESC-CMS可以产生平均为梗塞面积40%的移植物，它们通过机电耦合，与猕猴的心脏同步跳动，并在3个月内成熟到成年大小。这项提议解决了下一个层面的挑战。目的1是一项关键的疗效研究，将确定hESC-CMS是否能增强梗塞猕猴心脏的收缩功能。将对三种剂量的人类心肌细胞进行测试，并通过核磁共振确定心脏的结构和功能。目的2探讨我们最近研究中发现的室性心律失常的发生机制。除了通过遥测监测心率外，我们还将对植入的(3个细胞剂量)和假植入的灵长类心脏进行基于导管的连续标测，生成激活图，将心律失常归类为折返性或异位起搏器造成的心律失常。程序性电刺激将评估诱发心律失常的敏感性。结合目标1，这些研究将确定是否存在一种剂量的心肌细胞，可以增强功能而不出现心律失常。目的3使用分子成像技术评估移植物种群动态，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，验证了移植物诱导宿主冠状动脉重塑的假设，尽管有这种反应，移植物长期灌流不足。这些实验将为有计划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械性见解。

 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.