Biomimetic Engineering of Vascular Prostheses

描述（由申请人提供）：心血管疾病，包括冠状动脉疾病、中风和外周动脉疾病，是美国死亡的主要原因。临床上迫切需要一种容易获得的小直径（<5 mm ID）人造血管来治疗动脉粥样硬化性血管疾病。血管移植物假体成功实施的主要障碍是缺乏快速内皮化，沿着血栓形成和内膜增生（IH）。为了解决这些问题，我们提出开发一种新型的、可立即植入的仿生改性的市售小直径ePTFE移植物，其将促进快速体内内皮化和愈合，而不刺激血栓形成，并且不需要内皮细胞（EC）预接种。我们的总体假设是，小直径血管移植物上的EC功能可以通过利用对仿生表面活性剂聚合物中的EC表面受体具有高亲和力和特异性的肽来控制，所述仿生表面活性剂聚合物还将抑制血小板粘附和移植物血栓形成，并且可生物降解的外膜/中膜细胞外基质（ECM）模拟聚合物凝胶系统将促进移植物内的平滑肌细胞（SMC）掺入和愈合，不刺激IH。具体目标1将侧重于具有偶联细胞结合配体的仿生含氟表面活性剂聚合物上的EC功能，所述偶联细胞结合配体对ePTFE和模型氟硅烷表面上的EC而不是血小板具有选择性。仿生聚合物能够控制肽配体的密度和空间分布。侧配体将包括对1v 23（与1 IIb 23相比）表现出高亲和力和特异性的环状RGD肽、对1421具有特异性的REDV肽、对1521具有特异性的CRRETAWAC肽和对多配体蛋白聚糖表现出特异性的肝素结合肽。待测量的EC功能包括粘附、增殖、迁移、细胞骨架组织、基因表达、剪切稳定性、炎症状态和止血，以及与血小板的竞争性相互作用。目的二是利用血管特异性细胞结合肽和碳水化合物的组合，研究EC在仿生聚合物上的功能。在目标3中，我们提出开发一种可生物降解的ECM模拟凝胶，其在ePTFE纤维周围聚合，并被设计用于支持SMC掺入、收缩表型和移植物内的愈合。聚合物凝胶将掺入RGD和SMC结合1-肌营养不良聚糖和层粘连蛋白肽，这些肽存在于悬垂树突上。SMC结合功能将在单独的凝胶中进行研究，以及当掺入ePTFE血管假体的间隙中时进行研究。在目标4中，我们计划验证EC特异性仿生聚合物成功地调节体外EC功能，并且能够在体外灌注系统和慢性体内小直径血管移植猪模型中发挥作用。这些目标的成功完成将导致仿生ePTFE假体的发展，适用于长期的动物和临床研究。心血管疾病，包括冠状动脉疾病，中风和外周动脉疾病，是美国死亡的主要原因（1-3），为了帮助解决这一重大的公共卫生问题，迫切需要一种现成的，生物功能性小直径（<5 mm ID）动脉置换物（血管移植物假体）以治疗动脉粥样硬化性血管疾病。血管移植物修复成功的主要障碍是缺乏快速内皮化、血栓形成和内膜增生。拟议的研究将解决这些问题，通过开发一种新的，准备植入的仿生小直径移植物，将鼓励快速体内内皮化和愈合，而不会刺激血栓形成。该研究的成功完成将为临床研究提供合适的仿生血管移植假体。

DESCRIPTION (provided by applicant): Cardiovascular disease, including coronary artery disease, stroke and peripheral arterial disease, is the leading cause of mortality in the United States. There is an urgent clinical need for a readily available, small diameter (<5 mm ID) vascular prosthesis to treat atherosclerotic vascular disease. The main impediments to successful implementation of vascular graft prostheses are the lack of rapid endothelialization, along with thrombosis and intimal hyperplasia (IH). To address these problems, we propose to develop a novel, ready- to-implant biomimetic modification of commercially available small diameter ePTFE grafts that will encourage rapid in vivo endothelialization and healing without stimulating thrombosis and without the need for endothelial cell (EC) pre-seeding. Our overall hypothesis is that EC function on small diameter vascular grafts can be controlled by utilizing peptides with high affinity and specificity for EC surface receptors in a biomimetic surfactant polymer that will also suppress platelet adhesion and graft thrombosis, and that a biodegradable adventitial/medial extracellular matrix (ECM) mimetic polymer gel system will encourage smooth muscle cell (SMC) incorporation and healing within the graft, without stimulating IH. Specific Aim 1 will focus on EC function on biomimetic fluorosurfactant polymers with coupled cell binding ligands that are selective for EC and not platelets on ePTFE and model fluoro-silane surfaces. The biomimetic polymer enables control over the density and spatial distribution of peptide ligands. The pendant ligands will include cyclic RGD peptides that demonstrate high affinity and specificity for 1v23 (compared to 1IIb23), REDV peptide with specificity for 1421, CRRETAWAC peptide specific for 1521, and heparin binding peptides that demonstrate specificity for syndecans. EC functions to be measured include adhesion, proliferation, migration, cytoskeletal organization, gene expression, shear stability, inflammatory state, and hemostasis, as well as competitive interactions with platelets. Aim 2 focuses on investigating EC function on biomimetic polymers utilizing combinations of vascular-specific cell-binding peptides and carbohydrates. In Aim 3, we propose to develop a biodegradable ECM-mimetic gel polymerized around ePTFE fibrils and designed to support SMC incorporation, contractile phenotype, and healing within the graft. The polymer gel will incorporate RGD, and SMC-binding 1-dystroglycan and laminin peptides presented on pendant dendrons. SMC-binding functionalities will be studied in the gel alone, and when incorporated into the interstices of an ePTFE vascular prosthesis. In Aim 4, we plan to validate that EC-specific biomimetic polymers are successful in modulating in vitro EC function and able to function in an in vitro perfusion system and in a chronic in vivo small-diameter vascular graft porcine model. Successful completion of these aims will result in the development of a biomimetic ePTFE prosthesis suitable for longer-term animal and clinical studies.Cardiovascular disease, including coronary artery disease, stroke and peripheral arterial disease, is the leading cause of mortality in the United States (1-3), To help address this major public health problem, there is an urgent clinical need for a readily available, biofunctional small diameter (<5 mm ID) arterial replacement (vascular graft prosthesis) to treat atherosclerotic vascular disease. The main impediments to successful vascular graft prosthesis are the lack of rapid endothelialization, thrombosis and intimal hyperplasia. The proposed research will address these problems, through the development of a novel, ready-to-implant biomimetic small diameter graft that will encourage rapid in vivo endothelialization and healing without stimulating thrombosis. Successful completion of the research will provide biomimetic vascular graft prosthesis suitable for clinical studies.