Local delivery of smooth muscle cell targeted aptamer to inhibit neointimal growth and accelerate vascular healing

项目摘要 治疗阻塞性外周动脉疾病（PAD）患者的介入策略，影响8.5 在美国，100万成年人由于再狭窄率高而失败。再狭窄的一个重要过程是激活 血管平滑肌细胞（VSMCs），导致他们的迁移和增殖到内膜层，再- 阻塞了动脉在外周血管系统中，大多数支架断裂（高达68%）是由于过度 动脉变形，导致骨折部位的再狭窄并破坏药物释放动力学。在这些 例，球囊血管成形术往往是唯一的治疗选择，但结果不如支架。到 克服支架和球囊血管成形术在治疗PAD、药物涂层球囊（DCB）中的局限性 已经成为一种替代方法。DCB将药物局部递送到动脉壁上，而不需要 金属永久支架平台。到目前为止，DCB已经显示出急性成功，但未能显示长期- 术语治疗益处。然而，在机制上，DCB具有与DES类似的局限性，因为它们存款非 内膜表面上的特异性抗增殖药物，从而不利地靶向内皮细胞， 再内皮化此外，由DCB递送的抗增殖药物可产生下游栓塞， 增加截肢风险。在此，我们建议开发一种新的策略， 靶向治疗直接到达中间层。我们的初步结果表明成功交付VSMC- 特异性RNA适体通过新型灌注导管直接进入动脉中层。我们确认， 一种新的方法在临床相关的临床前研究中抑制新生内膜生长并加速再内皮化， 模型总的来说，该提议将检验RNA适体通过灌注导管直接递送的假设。 将抑制新生内膜生长并加速血管愈合过程中的再内皮化 过程改变条件以使用灌注导管最大化RNA递送和保留， VSMC增殖和再内皮化及适配体介导的VSMC抑制机制的研究 将探索增长（具体目标1）。这些研究将使用新型离体猪动脉完成 模拟外周动脉变形的循环系统。然后我们将定量RNA保留，血管 在猪损伤模型中的重塑和再内皮化（具体目标2）。最后，我们将评估 在患病的猪体内模型中，经处理的RNA动脉的血管反应和愈合（具体目标3）。 通过这些目标，我们将产生一种靶向治疗，抑制新生内膜生长，促进血管生成， 治愈这一创新性突破将重新定义介入治疗在PAD治疗中的成功。

Project Summary Interventional strategies to treat patients with obstructive peripheral artery disease (PAD), which affects 8.5 million adults in the US, are failing due to high rates of restenosis. A vital process in restenosis is the activation of vascular smooth muscle cells (VSMCs), resulting in their migration and proliferation into the intimal layer, re- occluding the artery. In the peripheral vasculature, the majority of stents fracture (up to 68%) due to excessive arterial deformation, resulting in restenosis at the fracture sites and disrupting drug release kinetics. In these cases, balloon angioplasty is often the only treatment option, however, outcomes are inferior to stents. To overcome the limitations of stents and balloon angioplasty in the treatment of PAD, drug coated balloons (DCBs) have emerged as an alternative approach. DCBs deliver drugs locally onto the arterial wall without the need of a metallic permanent stent platform. To date, DCBs have shown acute success but have failed to show long- term therapeutic benefit. Mechanistically though, DCBs have similar limitations to DES in that they deposit non- specific anti-proliferative drugs on the intimal surface, thereby adversely targeting endothelial cells and delaying re-endothelialization. Additionally, anti-proliferative drugs delivered by DCBs can produce downstream emboli, increasing amputation risks. Herein, we propose to develop a new strategy that delivers smooth muscle cell targeted therapy directly to the medial layer. Our preliminary results demonstrate successful delivery of VSMC- specific RNA aptamers directly to the arterial medial layer via a novel perfusion catheter. We confirm that this novel approach inhibits neointimal growth and accelerates re-endothelialization in a clinically relevant pre-clinical model. Overall, this proposal will test the hypothesis that RNA aptamer delivered by a perfusion catheter directly into the medial layer will inhibit neointimal growth and accelerate re-endothelialization during the vascular healing process. Varying conditions to maximize RNA delivery and retention using the perfusion catheter, determining VSMC proliferation and re-endothelization and identifying mechanism(s) of aptamer-medial inhibition of VSMC growth will be explored (Specific Aim 1). These studies will be accomplished using a novel ex vivo porcine artery circulatory system that mimics peripheral artery deformation. We will then quantify RNA retention, vessel remodeling and re-endothelialization in a porcine injury model (Specific Aim 2). Finally, we will evaluate the vascular response and healing of the treated RNA arteries in a diseased porcine in vivo model (Specific Aim 3). Through these aims, we will generate a targeted therapy that inhibits neointimal growth and promotes vascular healing. This innovative break-through will redefine the success of interventional therapy in the treatment of PAD.