Cardioprotective mechanisms of cell therapy for myocardial infarction

项目摘要/摘要 减少梗塞面积(IS)的新方法在翻译中停滞不前。一个主要的障碍是， 急性心肌梗死(AMI)的临床护理模式有一个主要目标：开放梗死灶- 尽快找到相关动脉。只有在血流恢复后，治疗医生才会花时间思考 关于辅助治疗，但到那时，招募经典心脏保护的机会之窗已经 很可能关闭，或者至少显著缩小。在这里，我们描述了细胞的新现象 后处理：细胞疗法在再灌流后30分钟(或更长时间；准确的时间定义为 目的是减少致命性损伤的程度，促进功能恢复。时机是 符合标准的临床实践，因为治疗的决定可以推迟到动脉 已打开，如果有现成的产品可用。同种异体心脏球源性细胞(CDCs)可用 立即使用，目前正处于慢性心肌梗死的第二阶段临床测试。这里我们展示的是初步数据， 对于大鼠和猪来说，CDC和它们的外切体在合理延迟给药时是有心脏保护作用的 在急性心肌梗死中回流后。我们考察了48小时的结构和功能终点，以确保重点关注急性 心脏保护；否则，不可能排除较长期的再生效应的一些贡献 疾病预防控制中心，仅在治疗几周后才明显出现。在猪遭受90分钟的缺血和30分钟的 再流时，冠脉内CDCs输注量减少，微血管范围也缩小 障碍物。在大鼠脑缺血45分钟后给予CDC 20分钟后，我们发现IS显著减少 这一发现现已得到一家主要的独立实验室的独立证实。我们进一步展示了初步的 表明巨噬细胞在心脏保护机制中起关键作用的数据。这里的主要焦点是 关于界定疾病预防控制中心减少IS的机制。我们测试了以下总体假设：疾控中心 分泌能修饰巨噬细胞以增强胞吐作用的外体。巨噬细胞究竟是如何 CDC的调控(是否涉及外切体转移的RNA？)，以及巨噬细胞如何减轻致命性 受伤，是这里讨论的主要问题。虽然我们关注的是疾控中心的心脏保护作用，但我们 预计这些措施将与再生效应协同，增加整体效益。两只成熟的动物 模型将接受急性心肌梗死：大鼠进行机械研究，尤卡坦小型猪进行翻译研究。这个 将通过巨噬细胞、中性粒细胞和中性粒细胞的体外共培养实验来探讨泡出作用的作用。 应激心肌细胞，以及通过体内实验对转基因大鼠的胞吐作用进行量化。这项工作 有可能阐明细胞疗法的心脏保护机制。

PROJECT SUMMARY/ABSTRACT Novel approaches to reduce infarct size (IS) have stalled in translation. A major obstacle is the fact that the clinical care paradigm for acute myocardial infarction (AMI) has one dominant objective: to open the infarct- related artery as quickly as possible. Only after flow is restored might the treating physician take time to think about adjunctive therapies, but by then the window of opportunity to recruit classical cardioprotection has most likely closed, or at least narrowed significantly. Here we characterize the novel phenomenon of cellular postconditioning: cell therapy delivered 30 min post-reperfusion (or even longer; defining the precise timing is an aim of this R01) can reduce the extent of lethal injury and improve functional recovery. The timing is compatible with standard clinical practice in that the decision to treat can be delayed until after the artery has been opened, if an off-the-shelf product is available. Allogeneic cardiosphere-derived cells (CDCs) are available for immediate use and are currently in phase 2 clinical testing for chronic MI. Here we show preliminary data, from both rats and pigs, that CDCs and their exosomes are cardioprotective when given with a reasonable delay after reflow in AMI. We looked at 48 hr structural and functional endpoints to ensure a focus on acute cardioprotection; otherwise it is impossible to exclude some contribution from longer-term regenerative effects of CDCs, which are evident only weeks after treatment. In pigs subjected to 90 mins of ischemia and 30 mins of reflow, the intracoronary infusion of CDCs decreased IS and also reduced the extent of microvascular obstruction. In rats we see large decreases of IS when CDCs are administered 20 mins after a 45 min ischemic episode, a finding now independently confirmed by a major unaffiliated laboratory. We further show preliminary data that implicate macrophages as key players in the mechanism of cardioprotection. The major focus here is on defining the mechanisms whereby CDCs reduce IS. We test the following overarching hypothesis: CDCs secrete exosomes which modify macrophages so as to enhance efferocytosis. Precisely how macrophages are modulated by CDCs (are RNAs transferred by exosomes involved?), and how macrophages mitigate lethal injury, are major questions addressed here. Although we focus on the cardioprotective effects of CDCs, we expect these to synergize with the regenerative effects, augmenting overall benefit. Two well-established animal models will be subjected to AMI: rats for mechanistic studies, and Yucatan minipigs for translational studies. The role of efferocytosis will be probed both by novel in vitro co-culture assays of macrophages, neutrophils, and stressed cardiomyocytes, as well as by in vivo experiments in transgenic rats to quantify efferocytosis. The work has the potential to elucidate the cardioprotective mechanisms of cell therapy.