Controlled gene delivery for in vivo vascularization of an engineered cardiac pat

描述（由申请人提供）：心脏病仍然是发达国家的主要死亡原因。大约有7000万美国人（超过人口的四分之一）患有心血管疾病，其死亡人数几乎是所有癌症死亡人数总和的两倍，每年治疗心血管疾病的费用约为3000亿美元（www.americanheart.org/presenter.jhtml?identifier=4478）。组织工程提供了在体外培养天然心肌功能等同物的潜力，用于组织修复，并研究治疗或预防疾病的新方法。然而，主要的挑战仍然存在，包括需要建立临床相关的人类细胞来源，并在体外培养和体内植入过程中使工程组织血管化。我们建议通过控制呈递到细胞的VEGF水平来设计一个具有高血管化能力的心肌组织斑块。我们解决的基本问题是，在体外培养和梗死心肌植入过程中，心肌细胞和表达VEGF水平可控的细胞共同培养是否可以用来介导血管网络的形成和成熟。该应用程序的直接目标是通过生物反应器在弹性体支架上共同培养心肌细胞和VEGF转染细胞，产生具有血管化能力的同步收缩心肌组织。我们提出了一系列重点突出且协调良好的体外研究（心脏和VEGF表达细胞的生物反应器共培养）和体内研究（在大鼠心脏梗死模型中），其具体目标如下：(1)基于新生大鼠心肌细胞和VEGF转染的成肌细胞设计心脏贴片。(2)生成VEGF释放谱可控的成体人干细胞。(3)基于新生大鼠心肌细胞和转染vegf的人干细胞构建心脏贴片。在所有情况下，细胞将在一个高度多孔的，通道弹性体支架上培养，使用先进的心脏组织工程生物反应器。将测定其活力、功能特性、与宿主组织的结合情况和血液灌注情况。计划中的工作，如果成功，将为使用成人干细胞来源的心脏和VEGF转染细胞的工程功能人类心脏移植物提供基础。我们目前无法将厚细胞团血管化和灌注，这阻碍了许多类型组织的构建，包括最关键的心肌。

DESCRIPTION (provided by applicant): Heart disease remains the leading cause of death in developed countries. About 70 million Americans (more than one-fourth of the population) live with cardiovascular disease, with a death toll that is almost twice as high as that for all cancer combined, and the cost of ~300 billion dollars spent every year to treat the cardiovascular disease (www.americanheart.org/presenter.jhtml?identifier=4478). Tissue engineering offers a potential to grow in vitro functional equivalents of native myocardium for use in tissue repair, and to investigate new ways to treat or prevent the disease. However, major challenges remain, including the need to establish a clinically relevant source of human cells, and to vascularize the engineered tissue, both during the in vitro cultivation and following implantation in vivo. We propose to engineer a patch of myocardial tissue with high capacity for vascularization, by controlling the levels of VEGF presented to the cells. The fundamental question we address is if co-culture of cardiac myocytes and cells expressing controllable levels of VEGF can be utilized to mediate the formation and maturation of a vascular network, during in vitro culture and following implantation onto infarcted myocardium. The immediate goal of this application is to generate synchronously contracting myocardial tissues with ability for vascularization, by bioreactor co-culture of cardiomyocytes and VEGF transfected cells on elastomer scaffolds. We propose a set of focused and well coordinated in vitro studies (bioreactor co-culture of cardiac and VEGF expressing cells) and in vivo studies (in a rat heart infarction model), with the following specific aims: (1) To engineer a cardiac patch based on neonatal rat cardimyocytes and VEGF-transfected myoblasts. (2) To generate adult human stem cells with controllable release profiles of VEGF. (3) To engineer a cardiac patch based on neonatal rat cardiomyocytes and VEGF-transfected human stem cells. In all cases, cells will be cultured on a highly porous, channeled elastomer scaffold, using an advanced bioreactor for cardiac tissue engineering. The viability, functional properties, integration with the host tissue and blood perfusion will be determined. The planned work, if successful, would provide a basis for engineering functional human cardiac grafts using cardiac and VEGF transfected cells derived from adult human stem cell sources. Our current inability to vascularize and perfuse thick cell masses has hindered efforts to build many types of tissues, including, most critically, cardiac muscle.