Biologically Inspired Engineering of Hierarchical Vascular Networks

描述（由申请人提供）：在美国每年有120万新发或复发的冠状动脉发作，导致心肌梗死或组织死亡。产生功能性心脏组织来替代受损组织可能会显著改变我们目前治疗心脏病的方式。因此，制造血管的强大方法可以促进更大规模心脏组织的生长，以治疗美国日益增加的疾病负担。我们的目的是在这个建议是增加一个血管网络，可以提供心脏移植物的营养运输在体外和连接到血液供应在体内。微制造技术允许在空间上精确地创建细胞指导性环境，并将用于在移植材料内形成100 μ m至1 mm通道的图案。模仿生理脉管系统，血管的分级组织的血管网络将被诱导为从相对大（毫米）到非常小（10 μ m）的管道的分支。心脏组织将使用水凝胶包封方法在血管结构周围生长。生物反应器将使用时变流体流动方案提供生物物理信号传导，以使血管沿着血管生成细胞因子成熟，从而诱导个体毛细血管发芽，从而提供细胞规模的运输。这种分层设计特别重要，因为它为体外连接创建了特定的入口和出口，并为体内手术吻合创建了清晰的末端，同时保持了微血管网络以实现有效的营养输送。这种设计弥合了通常缺乏有效运输至单个细胞的较大规模单一血管管与缺乏流体灌注的内皮细胞共培养研究之间的差距。心脏移植物的血管功能将在大鼠腹主动脉中通过端对端吻合术中的插入移植物进行体内评估。该提案的具体目标将是（1）使用微制造技术来创建用于血管形成的分层设计的模板，（2）应用生物物理调节来诱导毛细血管出芽，（3）在体内大鼠腹主动脉模型中功能性地测试心脏移植物的存活和功能灌注。该项目将建立在我们实验室以前在心脏组织工程方面的经验和专业知识的基础上，采用先进的生物微制造技术，创造出一种可以在体内使用的大型灌注心脏移植物。我们希望这些研究能够通过创造一种可用于心肌梗死和冠状动脉疾病患者的心脏补片来帮助减轻国家心血管疾病负担的整体努力。

DESCRIPTION (provided by applicant): There are 1.2 million new or recurrent coronary attacks each year in the U.S, resulting in myocardial infarction or tissue death. The generation of functional cardiac tissue to replace damaged tissue could significantly change the way we currently treat heart disease. Consequently, a robust method of fabricating blood vessels could facilitate growth of larger scale cardiac tissue for treating this increasing burden of disease in America. Our aim in this proposal is to add a vascular network which can supply the cardiac graft with nutrient transport in vitro and be connected to blood supply in vivo. Micro fabrication technologies allow for the spatially precise creation of a cell-instructive environment and will be used to pattern 100 um to 1 mm channels within a graft material. Mimicking physiologic vasculature, the hierarchically organized vascular network of blood vessels will be induced to branch from relatively large (millimeters) to very small (10 um) conduits. Cardiac tissue will be grown around the vessel structure, using a hydrogel encapsulation method. Bioreactors will provide biophysical signaling using a time varying fluid flow regime to mature the blood vessels along with angiogenic cytokines to induce individual capillary sprouting providing transport at the cellular scale. This hierarchical design is particularly important because it creates a specific inlet and outlet for in vitro connectivity and clear ends for surgical anastomosis in vivo, while maintaining a micro vascular network for efficient nutrient delivery. This design bridges the gap between larger scale singular vascular tubes which often lack effective transport to individual cells, and co culture studies with endothelial cells which lack fluid perfusion. The vascular functionality of the cardiac graft will be assessed in vivo an interposition graft in an end to end anastomosis in the rat abdominal aorta. The specific aims of the proposal will be to (1) Use micro fabrication technologies to create a hierarchically designed template for vascular formation, (2) Apply biophysical regulation to induce capillary sprouting, (3) Functionally test the survival and functional perfusion of the cardiac graft in an in vivo rat abdominal aorta model. This project will build upon our laboratory's previous experience and expertise in cardiac tissue engineering with advanced biological micro fabrication techniques, to create a large, perfused cardiac graft that can be used in vivo. We hope that these studies can aid to the overall effort to reduce the national burden of cardiovascular disease, by creating a cardiac patch that can be used for patients suffering from myocardial infarctions and coronary artery disease.