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。临床迫切需要一种易于获得的小直径（< 5mm ID）血管假体来治疗动脉粥样硬化性血管疾病。血管移植假体成功实施的主要障碍是缺乏快速内皮化，以及血栓形成和内膜增生（IH）。为了解决这些问题，我们建议开发一种新型的、可植入的拟生学修饰的商用小直径ePTFE移植物，它将促进体内快速内皮化和愈合，而不刺激血栓形成，也不需要内皮细胞（EC）预播种。我们的总体假设是，EC在小直径血管移植物上的功能可以通过在仿生表面活性剂聚合物中利用对EC表面受体具有高亲和力和特异性的肽来控制，这也会抑制血小板粘附和移植物血栓形成，并且可生物降解的外/内细胞外基质（ECM）模拟聚合物凝胶系统将促进移植物内平滑肌细胞（SMC）的结合和愈合，而不会刺激IH。具体目标1将重点关注EC在仿生氟表面活性剂聚合物上的功能，这些聚合物具有偶联细胞结合配体，对ePTFE和模型氟硅烷表面上的EC有选择性，而不是血小板。仿生聚合物可以控制多肽配体的密度和空间分布。悬垂配体将包括对1v23具有高亲和力和特异性的环状RGD肽（与1IIb23相比），对1421具有特异性的REDV肽，对1521具有特异性的CRRETAWAC肽，以及对syndecans具有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2侧重于研究EC在利用血管特异性细胞结合肽和碳水化合物组合的仿生聚合物上的功能。在目标3中，我们建议开发一种可生物降解的模拟ecm凝胶，该凝胶聚合在ePTFE原纤维周围，旨在支持移植物内SMC的结合、收缩表型和愈合。该聚合物凝胶将结合RGD和smc结合的1-三磷酸甘聚糖和层粘连蛋白肽，呈现在悬垂的树突上。smc的结合功能将在凝胶中单独进行研究，并将其纳入ePTFE血管假体的间隙中。在Aim 4中，我们计划验证EC特异性仿生聚合物成功调节体外EC功能，并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适合长期动物和临床研究的仿生ePTFE假体的发展。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，临床迫切需要一种现成的、具有生物功能的小直径（< 5mm ID）动脉替代物（血管移植假体）来治疗动脉粥样硬化性血管疾病。血管移植假体成功的主要障碍是缺乏快速内皮化、血栓形成和内膜增生。提出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，将促进体内快速内皮化和愈合，而不会刺激血栓形成。本研究的成功完成将为临床研究提供适合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.