【作者】 李嘉丽；

【导师】 钱菊英；

【作者基本信息】 复旦大学 ， 内科学， 2011， 硕士

【摘要】 研究背景：冠状动脉介入治疗目前已成为治疗冠心病最常用的一项治疗手段,而介入手术后可能出现的不良后果,如支架内再狭窄、支架内血栓、晚期支架贴壁不良以及冠状动脉瘤形成等情况,以及其引起的心血管不良事件,更是引起了医学界的高度重视。其中由于晚期支架贴壁不良(late stent malapposition, LSM)以及冠脉瘤(coronary artery aneurysm, CAA)形成的发生率较低,目前对于LSM及CAA的发生机制仍未明晾,有研究指出LSM以及CAA可能为一病变的连续过程,且可能与血管局部出现正性重构(vascular positive remodeling, VPR)有关,而目前针对支架置入术后可能出现血管重构方面的相关研究仍然不多。血管内皮生长因子(vascular endothelial growth factor, VEGF)是目前所发现的唯一一个血管内皮细胞特异性有丝分裂原,在许多血管病变以及肿瘤性疾病中参与了血管重构的过程,但VEGF是否参与了支架术后的血管重构尚不清楚。另外,有研究发现LSM与CAA在置入药物洗脱支架者的发生率高于置入裸支架者,可能与支架上药物的抑制细胞增殖作用有关,也可能为其载药涂层的存在导致血管壁炎症有关,但其具体原因仍然尚未明确。目的：本研究旨在研究VEGF与支架置入术后发生血管正性重构的关系,并通过比较不同类型支架置入后血管壁表达VEGF及巨噬细胞抗体(MAC)的差异,探讨支架类型影响血管发生正性重构趋势的机制。材料与方法：健康雄性新西兰大白兔60只,通过高脂饮食8周以及球囊拉伤的方法建立动脉粥样硬化模型后,随机分为4组,分别于随机一侧髂动脉植入裸支架(bare metal stent, BMS)、永久涂层西罗莫司药物支架(durable polymer sirolimus-eluting stent, DPS）、生物可吸收涂层西罗莫司药物支架(biodegradablepolymer sirolimus-eluting stent, BDS)以及无涂层西罗莫司药物支架(polymer-free sirolimus-eluting stent, PFS)。于支架置入术前、术后即刻以及术后8周行血管内超声(intravenous ultrasound, IVUS)了解血管重构的情况。于术后8周处死动物,取材支架置入段髂动脉,利用免疫组织化学方法检测髂动脉血管壁血管内皮生长因子(VEGF)与巨噬细胞抗体(MAC)的表达。结果：1)在术后8周,实验中53只动物中有17只出现了支架置入术后血管正性重构(VPR)。对比VPR者与非正性重构(NVPR)者其血管壁的VEGF表达有明显差异(VPR:28.53±6.66%; NVPR:19.74±3.57%; P<0.05)。分别在各支架组内对比同组VPR与NVPR的VEGF表达均有统计学差异(BMS组：27.75±10.74%比17.81±2.01%,DPS组：40.25±2.77%比20.62±4.28%,BDS组：35.04±3.52%比21.20±4.14%,PFS组：19.66±4.07%比16.25±1.72%；均为P<0.05)。经IVUS测得的术后即刻与随访时的血管外弹力膜面积差值(△血管外弹力膜面积,△EEM-CSA)与VEGF表达呈正相关的关系(r=0.65,P<0.05)。2)本实验中各支架组的VPR发生率分别为BMS组25.0%,DES组34.15%(DPS组42.86%,BDS组30.77%,PFS 28.57%),其中DPS组及BDS组分别各有1只出现了晚期支架贴壁不良,各组之间的VPR发生率比较无明显意义(P>0.05)。但对比各个支架组的△EEM-CSA, DPS组(0.86±0.38mm2)及BDS组(0.67±0.41mm2)分别与BMS组(－0.51±0.54 mm2)及PFS组(0.05±0.27 mm2)对比均有明显差异(P<0.05)；而DPS组与BDS组之间以及BMS组与PFS组之间的△EEM-CSA对比均无明显统计学意义(P>0.05)。对比各组出现VPR者的△EEM-CSA,亦以DPS-VPR组(2.47±0.35)2及BDS-VPR组(2.59±0.37)mm2分别与BMS-VPR组(0.96±0.45)mm2与PFS-VPR组(1.63±0.24)mm2对比有明显差异(P<0.05), DPS-VPR组与BDS-VPR组之间对比及BMS-VPR组与PFS-VPR组之间对比均无明显差异(P>0.05)。3)对比各支架组的VEGF表达,DPS组(30.45±9.57%)及BDS组(25.74±5.35%)分别与BMS组(21.11±4.32%)及PFS组(19.66±4.07%)对比皆有明显差异(P<0.05),而DPS组与BDS组之间以及BMS组与PFS组之间对比无明显差异(P>0.05)。对比各组出现VPR者的VEGF表达,DPS-VPR组(40.25±2.77%)及BDS-VPR组(35.04±3.52%)分别与BMS-VPR组(27.75±10.74%)及PFS-VPR组(19.66±4.07%)对比均有明显差异(P<0.05),当中DPS-VPR组与BDS-VPR组之间对比亦有统计学差异(P<0.05),而BMS-VPR组与PFS-VPR组之间对比无明显差异(P>0.05)。4)对比各支架组的MAC表达,以PFS组(18.99±2.45%)与其余3组对比均有明显差异(P<0.05)；DPS组(44.21±9.01%)与BDS组(32.99±3.52%)对比亦有明显差异(P<0.05)；而BMS组(35.30±7.79%)分别与DPS组及BDS组对比均无明显差异(P>0.05)。各支架组同组内VPR与NVPR对比其MAC表达均无明显差异,但各组均可见VPR者有表达增高的趋势(0.05<P<0.1)。结论：(1)在出现正性重构的血管壁中可发现明显升高的VEGF表达,且VEGF表达与血管的△EEM-CSA呈正相关,提示VEGF参与了支架置入术后血管重构的过程。(2)DPS组和BDS组可见更明显的△EEM-CSA及血管壁VEGF表达增高,同时发现该两组血管壁的MAC的表达增高,提示支架的载药涂层可引起血管壁明显的炎症反应,且炎症可能促使血管壁的VEGF表达增加,使该两组有更明显发生血管正性重构的趋势。更多还原

【Abstract】 Background:Percutaneous coronary intervention (PCI) has become a common treatment of coronary artery diseases. The adverse effects brought with PCI, such as stent restenosis, stent thrombus, late stent malapposition (LSM) and coronary artery aneurysm (CAA), are arousing great attention. The mechanism of LSM and CAA still remains unknown due to the low incidence. Previous studies demonstrated that vascular positive remodeling (VPR) played an important role in the formation of LSM and CAA. Vascular Endothelial Growth Factor (VEGF), which is the only specific mitogenic factor for vascular endothelial cells, is reported to be participated in many vascular remodeling in vascular diseases and tumors. But whether VEGF is also involved in the vascular remodeling after PCI is not clear.Objective:The aim of this study is to investigate the role of VEGF in vascular positive remodeling after stent-implantation. And differences of the expression of VEGF and macrophage antibody (MAC) between different types of stent-implantation are also analyzed to investigate the effect of different stents in the process of vascular positive remodeling.Method:60 healthy New Zealand rabbits were fed with high fat diet and endured balloon injury in both iliac arteries in order to achieve the atherosclerosis model. They were randomly divided into 4 groups and were implanted with base metal stents (BMS), durable polymer sirolimus eluting stents (DPS), biodegradable polymer sirolimus eluting stents (BDS) and polymer-free sirolimus eluting stents (PFS) in either iliac artery. We studied the intravenous ultrasound (IVUS) at 3 different time points (before stent-implantation, instant after stent-implantation and 8 weeks after stent-implantation) and analysis whether there was vascular positive remodeling. The animals were sacrificed 8 weeks after stent-implantation to obtained iliac artery tissues, the morphologic changes and expressions of VEGF and MAC were observed. Result:1) Vascular positive remodeling (VPR) was found in 17 vessel segments among all 53 segments at 8 weeks after stent-implantation. Vessel segments with VPR showed increased expression of VEGF compared with those with NVPR(VPR: 28.53±6.66%; NVPR:19.74±3.57%; P<0.05). And this variance existed in all groups(BMS:27.75±10.74% vs.17.81±2.01%, DPS:40.25±2.77% vs. 20.62±4.28%, BDS:35.04±3.52% vs.21.20±4.14%, PFS:19.66±4.07% vs. 16.25±1.72%; P<0.05). There was a positive correlation between the expression of VEGF and the△EEM-CSA (the difference between EEM-CSA of instant after stent-implanatation and 8 weeks later)2) The incidence of VPR among different stents in our study was BMS 25%, DES 34.15%(DPS 42.86%, BDS 30.77%, PFS 28.57%), including 2 cases of late stent malapposition occurred with DPS and BDS respectively. Incidences of VPR among these 4 groups were no statistical difference (P>0.05). However, significant increased△EEM-CSA were observed in Group DPS and Group BDS(DPS:0.86±0.38mm2, BDS:0.67±0.41mm2, P<0.05) but no statistical differences were observed between these two groups or between Group BMS and Group PFS (BMS:-0.51±0.54mm2, PFS:0.05±0.27mm2, P>0.05).△EEM-CSA in Group DPS-VPR and Group BDS-VPR were still apparently increased (DPS-VPR: 2.47±0.35mm2, BDS-VPR:2.59±0.37mm2, P<0.05), while no statistical differences were observed between Group DPS-VPR and Group BDS-VPR or between Group BMS-VPR and Group PFS-VPR (BMS-VPR:0.96±0.45mm2, PFS-VPR: 1.63±0.24mm2, P>0.05).3) The expression of VEGF in Group DPS and Group BDS (DPS:30.45±9.57%, BDS: 25.74±5.35) were higher than Group BMS (21.11±4.32%) and Group PFS (19.66±4.07%) (P<0.05), and no statistical differences were noted between Group BMS and Group PFS or between Group DPS and Group BDS(P>0.05). Among all the vessel segments with VPR, VEGF expression was increased in Group DPS-VPR and Group BDS-VPR (DPS-VPR:40.25±2.77%, BDS-VPR:35.04±3.52%) (P<0.05), statistical differences were observed between Group DPS-VPR and Group BDS-VPR but not between Group BMS-VPR and Group PFS-VPR (BMS-VPR:27.75±10.74%, PFS-VPR 19.66±4.07%) (P>0.05).4) The expression of MAC was apparently weaker in Group PFS (18.99±2.45%) than other groups(P<0.05), and statistical difference was also noted between Group DPS (44.21±9.01%) and Group BDS (25.49±2.03%), but not noted between Group BMS (35.30±7.79%) with Group DPS or with Group BDS (P>0.05). All groups of the vessel segment with VPR both expressed higher MAC than those with NVPR but there were no statistical differences (P>0.05).Conclusion:1) Expression of VEGF which significantly increased on the vessel segments with VPR, was positively correlated with△EEM-CSA. The result implied the role of VEGF in the vascular remodeling process.2) Enhanced△EEM-CSA and higher expression of VEGF and MAC were observed in Group DPS and Group BDS. Incidence of VPR may increase with these those types of stents due to the polymers which cause apparent inflammation and increase the expression of VEGF.更多还原