DYNAMIC IN VIVO VISUALIZATION OF ANASTOMOSIS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 组织工程有可能给再生医学带来革命性的变化。众所周知，营养物质的可获得性是工程组织存活的主要因素。在没有内部血管网络的情况下，只有薄的无血管组织才能在植入后保持存活。随着工程组织中促血管生成因子的受控释放，一个强大的微血管网络可以发展起来，尽管是以相对缓慢的方式。我们的研究团队最近的实验表明，在植入之前对工程化组织进行预血管化，可以加速与宿主血管形成功能性吻合。未知的是1)实现植入组织的灌流所需的准确时间和之前的事件，以及2)促进灌流的宿主组织特征。缺乏这样的知识是一个重要的问题，因为在这些知识变得可用之前，不太可能及时开发优化的策略来最大化植入的工程组织的生存能力。 我们的长期目标是开发一种功能强大的工程化组织，这种组织可以适应特定的再生医学应用。这项应用的总体目标是开发一种活体成像方法来确定植入组织的灌流时间进程，这是实现我们长期目标的下一步。我们的中心假设是，在我们目前开发纤维蛋白凝胶组织植入物的方案下，我们预计在我们的动物模型中，工程化组织在植入后48小时内就会出现灌流。这一假说是根据我们小组以前发表的组织学发现提出的。 主要的可检验假设是： 1.种植后24小时内出现种植体局灶性血流灌注。 2.根据内皮细胞类型的不同，整个种植体的灌流发生在植入后48小时内。 3.为了实现整个种植体的灌流，由于宿主和种植体血管之间的吻合部位很少，因此灌流的血管数量会突然增加。 我们计划通过追求以下具体目标来验证我们的假设并实现此应用程序的总体目标： 1.开发健壮的动物模型，能够实时显示宿主和植入物的微血管 2.建立宿主和种植体微血管内血流动力学的时程

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Tissue engineering has the potential to revolutionize regenerative medicine. It is well known that nutrient availability is a primary factor in engineered tissue viability. Without an internal vascular network, only thin avascular tissues can remain viable following implantation. With controlled release of proangiogenic factors within the engineered tissue, a robust microvascular network can develop, albeit in a relatively slow fashion. Recent experiments by our research team have demonstrated that prevascularization of engineered tissue prior to implantation, accelerates the formation of functional anastomoses with host vasculature. What is not known are 1) the precise time and preceding events required to achieve perfusion of the implanted tissue, and 2) the host tissue characteristics that promote perfusion. Lack of such knowledge represents an important problem because, until the knowledge becomes available, timely development of optimized strategies to maximize viability of implanted engineered tissues, is unlikely. Our long-term goal is to develop a functional, thick engineered tissue which can be adapted to specific regenerative medicine applications. The overall objective of this application, which is the next step toward attainment of our long-term goal, is to develop an intravital imaging approach to determine the time course of perfusion of the implanted tissue. Our central hypothesis is that, with our current protocols to develop fibrin gel tissue implants, we expect perfusion of the engineered tissue to develop within 48 hours after implantation in our animal model. This hypothesis was formulated on the basis of histological findings previously published by our group. The major testable hypotheses are: 1. Focal regions of implant perfusion occur within 24 h after implantation. 2. Perfusion of the entire implant occurs within 48 hours after implantation, depending on the endothelial cell type. 3. To achieve perfusion of the entire implant, the number of perfused vessels will increase in an abrupt manner, due to a minimal number of anastomic sites between host and implant vasculature. We plan to test our hypotheses and accomplish the overall objective of this application by pursuing the following Specific Aims: 1. Develop a robust animal model that enables real-time visualization of host and implant microvasculature 2. Establish the time course of perfusion dynamics within the host and implant microvasculature