Cell-free vascular grafts: immunological response and vascular regeneration

摘要 在美国，心血管疾病是主要的死亡原因。尤其是冠状动脉疾病 是最常见的疾病，每年有超过35万例搭桥手术，而 根据AHA的数据，估计每年的总成本为260亿美元。使用Native的组织工程方法 或合成支架，甚至无支架策略，已经开发出功能和可植入的血管 已经在小动物和大动物模型中以及在人类临床试验1-12中进行测试的移植物。在最近 多年来，该领域一直专注于工程无细胞(A)-TEV，作为一种潜在的替代方法，可能 提供用于治疗心血管疾病的现成移植物。最近，我们报道了成功的 序贯功能化的小肠黏膜下层A-TEV的研制 肝素和血管内皮生长因子(VEGF-165，记为VEGF)13，14。植入A-TEV 成功进入小(小鼠)15和大(羊)动物模型13的动脉循环，展示了 收缩血管壁的通畅、内皮化和再生。有趣的是，用血管内皮生长因子装饰的移植物 由抗炎的M2巨噬细胞填充，而单独含有肝素的血管移植物包含 主要是M1型巨噬细胞15。此外，含有血管内皮生长因子的移植物具有类似于 天然动脉，与没有血管内皮生长因子(仅有肝素)的移植物相比，血管内皮生长因子似乎杂乱无章，缺乏良好的... 明确内皮细胞和血管壁。这促使我们假设A-TEV的成功再生 在体内可能取决于产生抗炎和促进再生的环境，这可能是 由修饰移植物表面的固定化血管内皮生长因子(IVEGF)调节(至少部分)。 在这项提议中，我们试图从三个具体目标来研究这一假说。在目标1中，我们将探索 血管内皮生长因子调节炎症反应的机制。在目标2中，我们将使用小说 转基因小鼠模型监测单核细胞向移植物的渗透并研究血管内皮生长因子信号转导的作用 炎症和移植物再生。最后，在目标3中，我们将探讨长期通畅和重塑 在大型临床前动物模型(绵羊)中进行A-TEV的研究，以评估这些移植物的临床潜力。 这是一项极具创新性的提案，旨在调查如何调节炎症反应 影响血管移植物的通畅和再生。我们还试图确定这些药物的临床潜力。 基于血管内皮生长因子的A-TEVS在大型临床前动物模型中的应用。鉴于炎症反应的重要性 对于组织再生，我们的工作可能会对再生医学产生更广泛的影响。我们的生产力 在上一个资助周期(35种出版物)中，有希望的发现包括机械论和翻译学 来自我们实验室的研究和我们组建的优秀调查团队启发了我们 有信心这项工作能够在我们的实验室成功地进行。

ABSTRACT Cardiovascular disease is the leading cause of death in the United States. In particular, coronary artery disease is the most common disorder, with over 350,000 bypass grafting procedures performed every year and an estimated total cost of $26 billion annually, according to the AHA. Tissue engineering approaches using native or synthetic scaffolds and even scaffold-free strategies have developed functional and implantable vascular grafts that have been tested in small and large animal models, as well as in human clinical trials 1-12. In recent years, the field has focused on engineering acellular (A)-TEVs as a potential alternative approach that may provide off-the-shelf grafts for treatment of cardiovascular disease. Recently, we reported successful development of A-TEV based on small intestinal submucosa (SIS) that was functionalized sequentially with heparin and vascular endothelial growth factor (VEGF-165, denoted as VEGF) 13,14. This A-TEV was implanted successfully into the arterial circulation of small (mice) 15 and large (sheep) animal models 13, demonstrating patency, endothelialization and regeneration of contractile vascular wall. Interestingly, VEGF-decorated grafts were populated by anti-inflammatory, M2 macrophages, while vascular grafts containing heparin alone contained mostly M1 type macrophages 15. What is more, VEGF containing grafts had an architecture that was similar to native arteries, in contract to grafts without VEGF (heparin alone), which appeared disorganized and lacked well- defined endothelium and vascular wall. This prompted us to hypothesize that successful regeneration of A-TEV in vivo may depend on generating an anti-inflammatory and pro-regenerative environment, which may be modulated (at least in part) by the immobilized VEGF (iVEGF) decorating the surface of the grafts. In this proposal, we seek to investigate this hypothesis in three specific aims. In Aim 1, we will explore the mechanism through which VEGF modulates the inflammatory response. In Aim 2, we will employ novel transgenic mouse models to monitor monocyte infiltration into the grafts and study the role of VEGF signaling on inflammation and graft regeneration. Finally, in Aim 3 we will explore the long-term patency and remodeling of A-TEV in a large, pre-clinical animal model (ovine) to assess the clinical potential of these grafts. This is a highly innovative proposal that seeks to investigate how regulating the inflammatory response may affect the patency and regeneration of vascular grafts. We also seek to determine the clinical potential of these VEGF-based A-TEVs in a large, pre-clinical animal model. Given the importance of the inflammatory response for tissue regeneration, our work may have broader implications for regenerative medicine. Our productivity during the last funding cycle (35 publications), the promising discoveries including mechanistic and translational studies that originated from our laboratory, and the excellent team of investigators that we assembled inspires confidence that the work can be carried out successfully in our laboratories.