Engineering Vascularized Cardiac Muscle

描述(由申请人提供)： 我们目前无法将厚厚的细胞团血管化和灌流，这阻碍了对许多类型的功能组织进行工程设计的努力，其中最关键的是心肌组织。为了作为心肌修复的移植物，工程化心脏结构必须厚而紧凑，包含分化细胞的生理密度，并对电刺激做出同步收缩。此外，移植物必须具有与宿主血管系统整合的能力，以维持移植细胞的活性和功能。我们建议通过整合和推进我们在心脏组织工程(MIT)和血管组织工程(DUKE)领域正在进行的努力来设计功能性血管心肌。我们假设，在中等灌流和电刺激的生物反应器中，将心肌细胞和内皮细胞培养在专门的支架(高度多孔、可生物降解、有弹性、具有多个通道)上，将促进同步收缩工程肌肉的功能组装。我们进一步假设，体外血管化将提高移植物在体内的存活、整合和功能能力。为了验证这些假设，我们提出了以下特定目标的研究：(1)在中等灌流和电刺激的通道支架上高密度培养心肌细胞；(2)血管化网络的组织工程；(3)血管化心肌的组织工程和功能表征。将在体外和体内研究灌流和电刺激对内皮细胞和心肌细胞组装成同步收缩心肌的影响(植入成年大鼠梗死模型的左心室)。组织结构和功能将在不同的层次尺度(分子、结构、功能)进行表征，获得的实验和建模数据将用于定制培养条件和持续时间，并设计可植入移植物。因此，目前的建议是一个蓝图，以产生适合移植到受损心肌中的带血管心肌。

DESCRIPTION (provided by applicant): Our current inability to vascularize and perfuse thick cell masses has hindered efforts to engineer many types of functional tissues including, most critically, cardiac muscle. To serve as a graft for myocardial repair, an engineered cardiac construct must be thick and compact, contain physiologic density of differentiated cells, and contract synchronously in response to electrical stimulation. In addition, the graft must have a capability to integrate with the host vasculature in order to maintain the viability and function of transplanted cells. We propose to engineer functional vascularized myocardium by integrating and advancing our ongoing efforts in the areas of cardiac tissue engineering (MIT) and vascular tissue engineering (Duke). We hypothesize that the cultivation of cardiac myocytes and endothelial cells on specialized scaffolds (highly porous, biodegradable, elastic, with an array of channels) in a bioreactor with medium perfusion and electrical stimulation will promote functional assembly of synchronously contractile engineered muscle. We further hypothesize that vascularization in vitro will enhance the graft capacity for survival, integration and function in vivo. In order to test these hypotheses, which have been derived from two lines of our previous investigations, we propose studies with the following Specific Aims: (1) High density culture of cardiac myocytes on channeled scaffolds with medium perfusion and electrical stimulation, (2) Tissue engineering of a vascularized network, and (3) Tissue engineering and functional characterization of a vascularized cardiac muscle. The effects of perfusion and electrical stimulation on the progression of endothelial cell and myocyte assembly into a synchronously contractile myocardium will be studied in vitro and in vivo (implantation onto a left ventricle in an adult rat model of infarction). Tissue structure and function will be characterized at various hierarchical scales (molecular, structural, functional) and the obtained experimental and modeling data will be used to tailor the conditions and duration of cultivation and engineer implantable grafts. As such, the current proposal is a blueprint for the generation of vascularized cardiac muscle suitable for implantation into injured myocardium.