Biologically Inspired Engineering of Hierarchical Vascular Networks

描述(申请人提供)：在美国，每年有120万新发或复发的冠心病发作，导致心肌梗死或组织死亡。产生功能性心脏组织来取代受损组织可能会极大地改变我们目前治疗心脏病的方式。因此，一种健壮的血管构建方法可以促进更大规模的心脏组织的生长，以治疗美国日益加重的疾病负担。我们在这个方案中的目的是增加一个血管网络，在体外为心脏移植物提供营养运输，并与体内的血液供应相连接。微制造技术允许在空间上精确地创建细胞指导环境，并将用于在移植材料内形成100微米至1毫米的通道图案。模拟生理血管系统，分级组织的血管网络将被诱导从相对较大(毫米)的管道分支到非常小(10微米)的管道。心脏组织将在血管结构周围生长，使用水凝胶包埋方法。生物反应器将提供生物物理信号，使用时变的流体流动机制来成熟血管，以及血管生成细胞因子来诱导单个毛细血管萌发，提供细胞水平的运输。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，为体内外科吻合术创造了清晰的末端，同时保持了微血管网络以实现高效的营养输送。这种设计在较大规模的单一血管管和与内皮细胞共培养研究之间架起了桥梁，前者往往缺乏对单个细胞的有效运输，后者缺乏液体灌注。心脏移植物的血管功能将在体内进行评估，即在大鼠腹主动脉端到端吻合的间置移植物。该提案的具体目标将是(1)使用微制造技术来创建分层设计的血管形成模板，(2)应用生物物理调节来诱导毛细血管萌发，(3)在活体大鼠腹主动脉模型中从功能上测试心脏移植物的存活和功能灌流。该项目将以我们实验室以前在心脏组织工程方面的经验和专业知识为基础，采用先进的生物微制造技术，创造出可在体内使用的大型灌流心脏移植物。我们希望这些研究可以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贴片，来帮助减轻全国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.