In vivo vascular delivery of an MK2 inhibitory peptide for the prevention of smooth muscle cell phenotype switch and intimal hyperplasia.

项目摘要 外周动脉疾病（PAD），一种导致外周动脉阻塞的动脉粥样硬化疾病， 影响了美国超过650万人PAD减少血流，导致肢体疼痛，伤口不愈合， 在极端情况下甚至死亡。经皮腔内血管成形术（PTA），包括在球囊扩张时， 在阻塞部位重新打开动脉腔，是PAD的常用治疗方法。然而，血管壁应力 与球囊扩张相关（有时与支架置入结合）的损伤和激活 组织中的应力反应，导致再狭窄，动脉再狭窄。由于这些并发症， 大多数PTA治疗的血管在前12个月内失效。呼吸是由病理过程内膜 增生（IH），其特征在于血管平滑肌细胞（VSMC）从收缩性转变为 合成表型，使它们变得更加迁移，增殖，并在分泌细胞外 基质（ECM）和炎性细胞因子。合成的VSMC活动产生新生内膜， 血管，并作为一个肥沃的土壤先进的动脉粥样硬化，甚至血栓形成。当前治疗 减少IH的策略仅集中于通过使用药物涂层球囊抑制VSMC增殖， 支架。然而，这些方法在临床试验中没有显示出改善血管通畅性的前景。我有 一直在寻求抑制p38-MK2“应激反应”信号通路作为更全面的IH 靶向驱动病理性VSMC表型转换的潜在机制的治疗。在我最近 研究中，通过使用一种新的肽治疗剂（MK2 i）抑制MK2，所述肽治疗剂与 形成纳米复合物（MK2 i-NPs）的pH敏感性内体溶解聚合物被证明在生物医学领域是有前途的。 抑制VSMC增殖、表型转换和IH。在血管旁路移植术的背景下， 血管移植模型显示，用MK2 i-NP（局部至局部）的单次术中治疗 组织）在术后28天内抑制新生内膜形成，并在术后28天内减轻VSMC表型转换。 移植后急性（7天）应激反应期。我们假设在体内，基于导管的递送 MK2 i联合球囊血管成形术将防止VSMC表型转换， 再狭窄和血管衰竭。为了模拟从专用导管的体内递送，我将开发一个体外 生物反应器系统，并应用该系统来评估压力对MK2 i渗透和保留的影响 在血管壁上。此外，我们将使用生物反应器来评价药代动力学和药效学 MK2 i在离体动脉中的表达。最后，基于初始工作中优化的压力条件， 专门的闭塞灌注导管，以在血管的管腔内产生“腔室”， MK2 i-NP可以可控地施用以用于体内对流转移到血管壁中。该系统将 在猪模型中展开以评估体内MK2 i递送对维持VSMC收缩性的影响。 表型和PTA后的总体血管通畅性。

PROJECT SUMMARY Peripheral artery disease (PAD), an atherosclerotic disease leading to peripheral artery obstruction, affects over 6.5 million people in the US. PAD reduces blood flow, causing limb pain, non-healing wounds, and in extreme cases even death. Percutaneous transluminal angioplasty (PTA), involving inflation of a balloon at the site of blockage to re-open the arterial lumen, is a common treatment for PAD. However, vascular wall stress associated with balloon distension (sometimes in combination with stent placement) damages and activates stress response in the tissue, leading to restenosis, a re-narrowing of the artery. Because of these complications, most PTA-treated vessels fail within the first 12 months. Restenosis is driven by the pathological process intimal hyperplasia (IH), characterized by vascular smooth muscle cells (VSMCs) switching from a contractile to synthetic phenotype, causing them to become more migratory, proliferative, and active in secreting extracellular matrix (ECM) and inflammatory cytokines. Synthetic VSMC activities produce neointima that closes back off the vessel and that serves as a fertile ground for advanced atherosclerosis or even thrombosis. Current therapeutic strategies to reduce IH focus solely on inhibiting VSMC proliferation through the use of drug coated balloons and stents. However, these methods have not shown promise in improving vessel patency in clinical trials. I have been pursuing inhibition of the p38-MK2 “stress response” signaling pathway as a more comprehensive IH therapy that targets the underlying mechanisms that drive the pathological VSMC phenotype switch. In my recent studies, inhibition of MK2 through the use of a novel peptide therapeutic (MK2i) electrostatically complexed with a pH-sensitive endosomolytic polymer to form nanopolyplexes (MK2i-NPs) proved to be promising in the inhibition of VSMC proliferation, phenotype switching, and IH. In the context of vascular bypass grafts, a rabbit vascular transplant model showed that a single intra-operative treatment with MK2i-NPs (topically to explanted tissue) inhibited neointima formation up to 28 days after surgery and mitigated VSMC phenotype switching during the acute (7 day) stress response phase post-transplant. We hypothesize that in vivo, catheter-based delivery of MK2i in conjunction with balloon angioplasty will prevent VSMC phenotype switching and protect against restenosis and vessel failure. To model in vivo delivery from a specialized catheter, I will develop an ex vivo bioreactor system and apply this system to evaluate the effects of pressure on MK2i penetration and retention in the vessel wall. Additionally, we will use the bioreactor to evaluate pharmacokinetics and pharmacodynamics of MK2i in arteries ex vivo. Finally, based on the pressure conditions optimized in initial work, we will apply a specialized occlusion perfusion catheter to create a “chamber” within the lumen of the vessel through which the MK2i-NPs can be controllably administered for convective transfer into the vascular wall in vivo. This system will be deployed in a pig model to assess the effect of in vivo MK2i delivery on maintenance of VSMC contractile phenotype and overall vessel patency following PTA.