Increasing biocompatibility of stents via CD47 surface functionalization: Mechanistic and Preclinical studies

摘要/概要 与血管内支架使用相关的病理生理学已得到充分记录，并在多达 50%的患者接受了医疗器械。CD 47是一种广泛表达的跨膜蛋白， 当与其同源受体信号调节蛋白α（SIRP α）结合时， 反应我们已经在体外和大鼠颈动脉支架模型中表明，固定化重组CD 47， 或其21个氨基酸的肽序列（pepCD 47），显著抑制再狭窄和血栓形成。的 本研究的总体目标是研究pepCD 47的抗再狭窄能力 在兔和猪动物模型中的功能化血管内支架。三个具体目标（SA）将测试我们的 中心假设，固定化pepCD 47代表了一种实用的表面修饰策略， 控制不良的免疫和血液相容性反应，从而显著有助于 血管内支架的生物相容性。在SA 1中，我们将制作并进行有效性和稳定性分析 在CD 47功能化的金属表面，以测试我们的工作假设，兔和猪的CD 47，固定 在裸露的金属表面上，将赋予与人CD 47相似的抗血小板和抗炎活性， 将能够应对临床相关的挑战。SA 2将确定固定化的CD 47如何影响 血液/支架界面的细胞相互作用。我们的工作假设是，固定的CD 47赋予 生物相容性微环境，抑制炎症细胞和血小板的相互作用，并允许再- 内皮化SA 3将证明CD 47功能化支架在大血管中的体内功效。 动物模型我们的工作假设是，CD 47修饰的支架将赋予显著更大的 与市售裸金属支架和药物洗脱支架（DES）相比， 将通过支架植入部位的ISR显著减少来证明。建议的理由 研究表明，在大型动物模型中pepCD 47介导的ISR抑制将提供 必要的临床前和使用数据，以推进CD 47功能化支架在 临床领域这项研究是重要的，因为它将证明广泛的翻译重要性， CD 47在调节细胞/分子对用于临床相关的合成表面的反应中的作用 生物医学设备本文提出的研究是创新的，因为它挑战和重定向当前 治疗策略，如DES，通过识别候选分子信号传导机制， 调节细胞与固体合成表面的相互作用，然后将这些概念纳入 金属支架的设计和制造。

Abstract/Summary The pathophysiology associated with endovascular stent usage is well documented and is observed in up to 50% of all patients receiving the medical device. CD47 is a ubiquitously expressed transmembrane protein, that when bound to its cognate receptor Signal Regulatory Protein alpha (SIRP), inhibits the immune response. We have shown, both ex vivo and in a rat carotid stent model, that immobilized recombinant CD47, or a 21 amino acid peptide sequence (pepCD47) thereof, significantly inhibited restenosis and thrombosis. The overall objective of the proposed research is to investigate the anti-restenotic capacity of a pepCD47 functionalized endovascular stent in rabbit and porcine animal models. Three Specific Aims (SA) will test our central hypothesis that immobilized pepCD47 represents a pragmatic surface modification strategy that will control adverse immunological and hemocompatibility responses and thus significantly contribute to biocompatibility of endovascular stents. In SA 1 we will fabricate and perform efficacy and stability analysis on CD47 functionalized metal surface to test our working hypothesis that rabbit and pig CD47, immobilized on the bare metal surfaces, will confer a similar anti-platelet and anti-inflammatory activity as human CD47 and will be amenable to clinically relevant challenges. SA 2 will determine how immobilized CD47 affects cellular interactions at the blood/stent interface. Our working hypothesis is that immobilized CD47 confers a biocompatible microenvironment that inhibits inflammatory cell and platelet interactions and permits re- endothelialization. SA 3 will demonstrate in vivo efficacy of CD47 functionalized stents in the large animal models. Our working hypothesis is that CD47 modified stents would confer significantly greater biocompatibility, compared to commercially available bare metal stents and drug eluting stents (DES), which will be demonstrated by a significant reduction in ISR of the stented site. The rationale for the proposed research is that demonstration of pepCD47 mediated inhibition of ISR in a large animal model would provide necessary preclinical and usage data to advance the application of the CD47-functionalized stents into the clinical realm. The research is significant because it will demonstrate the broad translational importance of CD47 in regulating the cellular/molecular response to synthetic surfaces that are used in clinically relevant biomedical devices. The research proposed herein is innovative because it challenges and redirects current therapeutic strategies, such as DES, by identifying candidate molecular signaling mechanisms that actively regulate cellular interactions with solid synthetic surfaces, and then incorporating these concepts into the design and fabrication of metallic stents.