Embryonic Stem Cell-based Therapies for Myocardial Infarction

急性冠状动脉血栓形成导致心肌梗死(Ml)，并伴有不可逆转的功能丧失 除非迅速开展再灌流治疗，否则不会造成心肌梗死。许多病人不在场或不在场 易于迅速再灌注，在这个庞大的患者群体中，新的治疗方法是 需要的。在动物模型和患者中对Mi后基于细胞的治疗的初步研究提供了 结果令人鼓舞，但理想的捐献细胞数量尚未确定。初步数据显示 未分化小鼠胚胎干细胞(ESCs)在Mi后移植导致心肌梗死 在小鼠ML模型中进行修复；然而，主要的机械问题和障碍仍然存在，如风险 肿瘤的形成。我们假设细胞制剂来源于致力于 中胚层或心脏谱系可以以最小的肿瘤发生风险修复心肌。其次，我们 假设移植胚胎干细胞来源的细胞的最佳益处是短期内 通过旁分泌效应和心肌的长期再生减少梗塞面积 在没有明显融合的情况下，移植细胞的增殖和分化。长期目标 这项研究的重点是开发使用ESCs的细胞疗法来修复ML术后的心肌 提供基本的临床前有效性和安全性研究。我们建议：1)识别和表征 干细胞来源的供体细胞用于心肌修复最理想，使用细胞表面成瘤风险最小 分离中胚祖细胞和胚胎的标记和遗传细胞类型特异性报告 2)发展策略以改善供体细胞的存活率。 利用缺血和氧化应激体外模型研究Mi后心脏的典型缺血和氧化应激 再灌注；3)确定胚胎干细胞及其衍生物在Mi后移植的效果 短期(梗塞范围、细胞存活、细胞增殖)和长期(通过 超声心动图和组织学，肿瘤的MicroCT监测和病理，细胞命运/融合 免疫标记和Cre/LOX供体/受体技术，以及再生心肌细胞表型 电生理学)结果。总体而言，这些研究将为基于细胞的治疗提供新的见解 并使使用人类胚胎干细胞的方法更接近临床应用。

Acute coronary thrombosis results in myocardial infarction (Ml)with irreversible loss of functional myocardium unless reperfusion therapy is rapidly instituted. Many patients do not present or are not amenable to prompt reperfusion, and in this large patient population new therapeutic approaches are needed. Initial studies of cell-based therapies post-Mi in animal models and in patients have provided encouraging results, but the ideal donor cell population has not been determined. Preliminary data show that transplantation of undifferentiated mouse embryonic stem cells (ESCs) post-Mi, resulted in myocardial repair in a mouse Ml model; however, major mechanistic questions and roadblocks remain such as the risk of tumor formation. We hypothesize that cell preparations derived from ESCs that are committed to mesodermal or cardiac lineages can repair the myocardium with minimal risk of tumorigenesis. Secondly, we hypothesize that the optimal benefit from transplanted ESC-derived cells is the result of a short-term reduction in infarct size via paracrine effects and long-term regeneration of myocardium resulting from the proliferation and differentiation of transplanted cells in the absence of significant fusion. The long-term goal of this research is to develop cellular therapies using ESCs to repair the myocardium following Ml by providing essential preclinical studies of efficacy and safety. We propose to: 1) identify and characterize ESC-derived donor cells optimal for myocardial repair with minimal risk of tumorigenesis using cell surface markers and genetic cell-type specific reporters to isolate mesodermal progenitor cells and embryonic ventricular myocytes; 2) develop strategies to condition donor cells for improved survival in the setting of ischemic and oxidative stress typical of the post-Mi heart employing in vitro models of ischemia and reperfusion; and 3) determine the effect of transplantation of ESCs and derivatives post-Mi evaluating both short-term (infarct size, cell survival, cell proliferation) and long-term (LV structure and function by echocardiography and histology, tumor surveillance with microCT and pathology, cell fate/fusion by co- immunolabeling and Cre/lox donor/recipient techniques, and regenerated myocytes phenotype using cellular electrophysiology) outcomes. Overall, these studies will provide new insights into cell-based therapies in the post-Mi setting and bring approaches using human ESCs closer to clinical application.