microRNA-145/VEGF双基因内外涂层支架的制备及植入初期支架内再狭窄的抑制功效评价

Coronary balloon angioplasty and coronary stenting are the procedures used in healing coronary artery disease. However, injury of arteries during angioplasty and stenting causes cell stimulations in tissue. Cell movement and thrombosis lead to re-narrowing of widened vessel called restenosis. Among the available strategies for preventing restenosis, the drug-eluting stent (DES) is widely used in clinical practice，But there are still risks, such as re-endothelialization. The proliferation of vascular smooth muscle cells (VSMCs) and re-endothelialization is an important pathological event in atherosclerosis and restenosis. For effective treatment of restenosis, therapeutic genes are delivered locally from a coated stent at the site of injury, leading to inhibition of smooth muscle proliferation and neo-intimal hyperplasia while promoting re-endothelialization. In this proposal, was to develop a dual gene-coated sent using a bi-directional coating system. MicroRNA 145 was immobilized onto the abluminal area of the stent to suppress smooth muscle cells, and vascular endothelial growth factor (VEGF) was immobilized onto the luminal area of the stent to promote re-endothelialization. The bi-directional coating stent could be suppressing in-stent restenosis efficiently with no side effects and can be considered a successful substitute to the current drug-eluting stent.

冠状动脉球囊成形术和冠状动脉支架植入术是常用于治疗冠状动脉疾病的措施。然而支架的植入损伤了动脉的内皮细胞，导致血管平滑肌细胞向损伤部位迁移增殖形成血栓，引起支架内再狭窄。随着药物洗脱支架的使用，抑制再狭窄效果明显提高，但仍存在风险，包括再内皮化。抑制平滑肌细胞的增值及迁移和促进再内皮化是解决支架内再狭窄问题的主要研究方向。本项目立足于此理论基础上，将设计开发一种新型的双基因内外涂层支架，由抑制平滑肌细胞增殖迁移的microRNA-145和促进再内皮化作用的vascular endothelial growth factor来进行涂层。我们还将利用细胞实验研究双基因涂层支架对平滑肌细胞和内皮细胞的调节机制，并通过小鼠皮下的释放和表达实验对双基因涂层支架进行初步评价。在本项目，通过双基因内外涂层支架可有效地无副作用地抑制支架内再狭窄,也希望成功替代当前药物涂层支架的新技术。

再狭窄是指成功介入治疗手术,受治疗冠脉局部损伤后“愈合”反应而造成局部血管腔的再次狭窄。抑制平滑肌细胞的增值及迁移和促进再内皮化是解决支架内再狭窄问题的主要研究方向。.通过本研究，我们设计开发一种新型的microRNA-145/VEGF内外涂层支架，由抑制平滑肌细胞增殖迁移的microRNA-145和促进再内皮化作用的Vascular endothelial growth factor来进行涂层。 通过本研究发现microRNA-145/VEGF纳米颗粒表现出稳定地结合和定位在 Hyaluronic acid (HA)的金属介质表面，内皮细胞和平滑肌细胞也很好地吸附在纳米颗粒表面。通过时间段释放实验确定，72小时时microRNA-145/VEGF从HA涂层金属介质表面上释放出超出70%。我们还检测出平滑肌细胞标志蛋白和miR-145靶基因KLF4、c-Myc表达变化，发现VEGF蛋白增加平滑肌细胞标记基因SM-MHC蛋白减少、miR-145下游c-Myc蛋白明显增加。在体内实验，我们利用了澳洲白兔动物模型，将microRNA-145/VEGF涂层的HA金属支架植入到兔子的髂动脉，研究表明，从支架释放的microRNA-145/VEGF抑制了平滑肌的生长，促进了支架置入术周区域的再内皮化，从而预防了植入后再狭窄问题。