Microstructural Cues for the Treatment of Heart Failure

项目摘要/摘要 急性心肌梗死(MI)并发疤痕组织的后续发展导致 慢性心功能不全。不幸的是，缺乏对这种适应不良的纤维化反应的治疗通常 会导致不良的预后。干细胞移植和生物疗法的早期尝试解决了这一问题 问题是有希望的，但不一致。为了迎接这一挑战，德赛实验室与合作者一起， 开发了一种独特的随机分散的聚合物微结构系统，称为微棒，它具有 已发现在体外可抑制成纤维细胞的增殖，促进心肌细胞的肥大。目标是 这项建议的目的是研究微棒与心脏成纤维细胞体外相互作用的机制。 在脑梗塞的动物模型中。我们还将研究心脏微结构对心脏重塑的影响。 这将使设计更有效的治疗方法来防止心脏疤痕组织的发展和 促进心肌梗塞后心功能的恢复。基于前人的研究和最近的研究 机械微环境，假设原代成人心室成纤维细胞将对 微棒的存在，在与之相关的途径中具有一组独特的转录变化 机械转导、微环境相互作用和细胞外基质沉积。在目标1中， 基因表达变化的定量分析和免疫荧光显微镜将用于 在3D培养中检查细胞与微棒的相互作用。具体地说，ECM下调的量化 而力学传导相互作用将阐明微结构对成纤维细胞影响的机制。 此外，还将开发HepIII共轭微棒，以增强血管形成，这是另一个关键 心脏再生的要素。AIM 2将使用定量生化和免疫组织化学技术 在已建立的心肌梗死大鼠模型中，测试向梗死区注射微量药物将导致 纤维反应标志物的转录变化与体外观察到的类似，通过与 心脏成纤维细胞群，以及在微棒中加入HepIII所产生的血管生成。 最后，目标3将评估注射微棒在慢性缺血环境中的治疗效果。 活体初步结果提示的心肌病。注射微球后的疗效将会是 通过系列超声心动图测量以评估射血分数和心脏解剖与梗塞的关系 疤痕与血管生成。通过减少纤维化瘢痕，诱导血管生成，促进心肌 再生，可注射的微棒将有助于改善心肌梗死后的结果。了解这些 机制将导致设计和优化补充疗法和药物输送 可能性，这将推动NHLBI治疗心脏病以增进所有人健康的使命 这样他们才能活得更长、更有成就感。

Project Summary/Abstract Acute myocardial infarction (MI) is complicated by the subsequent development of scar tissue leading to chronic cardiac insufficiency. Unfortunately, the lack of treatments for this maladaptive fibrotic response often leads to a poor prognosis. Early attempts at stem cell delivery and biological therapeutics to address this problem have been promising, but inconsistent. To meet this challenge, the Desai lab, with collaborators, has developed a unique system of randomly dispersed polymeric microstructures, termed microrods, that have been found to decrease fibroblast proliferation and promote cardiomyocyte hypertrophy in vitro. The objective of this proposal is to study the mechanisms of interaction between microrods and cardiac fibroblasts in vitro and in an animal models of infarct. We will also examine the effect of microstructures on cardiac remodeling. This will enable the design of more effective therapies to prevent the development of cardiac scar tissue and encourage recovery of heart function after MI. Based on previous studies and recent research on the mechanical microenvironment, it is hypothesized that primary adult ventricular fibroblasts will respond to the presence of microrods with a unique set of transcriptional changes in pathways relevant to mechanotransduction, micro-environmental interaction, and extracellular matrix (ECM) deposition. In Aim 1, quantitative analyses of changes in gene expression and immunofluorescence microscopy will be used to examine cellular interactions with microrods in 3D culture. Specifically, quantification of ECM down-regulation and mechanotransductive interactions will elucidate the mechanisms of effect of microstructures on fibroblasts. In addition, HepIII conjugated microrods will be developed in order to augment vascularization, another key element of cardiac regeneration. Aim 2 will use quantitative biochemical and immunohistochemical techniques in an established rat model of MI to test the hypothesis that microrod injection into the infarct zone will produce similar transcriptional changes in markers of the fibrotic response as seen in vitro through interaction with the cardiac fibroblast population, as well as angiogenesis produced with the addition of HepIII to the microrods. Finally, Aim 3 will evaluate the therapeutic benefit of injected microrods in the setting of chronic ischemic cardiomyopathy as suggested by preliminary in vivo results. Therapeutic effect after microrod injection will be measured by serial echocardiograms to assess ejection fraction and cardiac anatomy in relation to the infarct scar and angiogenesis. By decreasing fibrotic scarring, inducing angiogenesis and promoting myocardial regeneration, injectable microrods will contribute to improving outcomes after MI. Understanding these mechanisms will lead to the design and optimization of complementary therapies and drug delivery possibilities, which will further the NHLBI's mission of treating heart disease to enhance the health of all individuals so that they can live longer and more fulfilling lives.