血管成形术后外膜细胞表型转化和迁移的实验研究

目的观察和分析血管成形术后血管外膜成纤维细胞表型转化和外膜细胞向血管内膜的迁移。方法改良导丝法损伤24只大鼠颈总动脉(CCA),制作血管再狭窄模型;采用5-溴,2尿苷嘧啶(BrDU)标记增殖和迁移的成纤维细胞,以免疫组化,BrDU单染结合α-肌动蛋白(α-actin)复染,光镜、扫描电镜和图像分析仪观察和分析损伤后3、7、14和28d,血管外、中和内膜上与BrDU结合的成纤维细胞的动态分布。结果1.免疫组化染色:BrDU结合的外膜成纤维细胞在术后第3天外膜上分布较多,至第7天达到峰值并表达α-actin,成纤维细胞发生表型转化成为成肌纤维细胞,细胞外基质(ECM)沉积;第14天,外膜上阳性细胞数下降,中膜和内膜上数量显著上升,内膜增厚,管腔狭窄;第28天,外膜、中膜和内膜阳性细胞数量回归到基线,但内膜ECM沉积较多,内膜仍增厚,管腔狭窄。不同时间点,血管三层结构内阳性细胞数比较均有显著差异(P<0.05)。2.电镜观察:血管成形术后,成纤维细胞胞质饱满,粗面内质网发达,表面分泌颗粒丰富,合成大量微丝束,转化为成肌纤维细胞;第7和14天,成肌纤维细胞形成宽大的伪足,分别伸向血管外弹力板窗孔和内弹力板窗孔,细胞呈腔内方向迁移趋势。结论血管成形术后血管外膜成纤维细胞发生表型转化,合成分泌α-actin;外膜成纤维细胞转化为成肌纤维细胞,向血管内膜迁移、增殖,成为新生内膜的细胞成分;外膜细胞和血管再狭窄有关。     

兔腹主动脉球囊成形术后狭窄过程中内皮素的动态变化

目的观察血管内膜损伤后狭窄过程的主要病理变化特征，研究此过程中血浆内血管内皮素(ET)水平及局部动脉组织内ET反应性(ET-IR)的改变，以探讨血管狭窄的发生与ET变化的关系。为临床寻求针对ET因素的治疗处理和预防血管成形术后再狭窄提供理论依据。方法大耳白兔30只，依术后处死时间不同(6h和1、3、7、15、22d)随机分为6组，每组5只，3只内膜损伤、2只组内对照(假手术)。术前及术后处死前均采血，置入微球囊导管于腹主动脉内拉动制备内膜损伤动物模型。对照组不插入球囊导管，以放射免疫法检测血浆内ET水平，行病理形态学观察血管内膜厚度及管腔狭窄情况，以免疫组织化学法检测动脉组织内ET反应。结果损伤组各时间段血浆ET水平均较术前及假手术组有明显升高，损伤组血管内膜增厚，术后15～22d时可见血管平滑肌细胞(VSMC)增殖并迁移到内弹力膜层内，堆积重叠甚至呈瘤样突起而致血管腔变窄，血浆ET水平与血管内膜厚度及管腔狭窄程度呈一致性。结论VSMC增殖和内膜增厚是再狭窄的主要病理特征。ET参与心血管收缩、VSMC增殖和血栓形成，在血管球囊成形术后血管狭窄过程中起到了关键的作用。拮抗或抑制ET生成的生物学作用，对防治再狭窄可能具有重要的临床意义。     

血管活性肽在血管再狭窄中的作用

因介入技术的发展和介入器材的不断开发应用，经皮穿刺血管腔内球囊成形术成为治疗冠心病等血管狭窄性疾病的重要措施，但术后发生的再狭窄仍是影响其疗效的主要因素之一。再狭窄发生的确切机制目前尚未完全清楚。大量的临床资料和实验研究表明，血管平滑肌细胞(Vascular smooth muscle cell，VSMC)增殖和内膜增厚是再狭窄(RS)的主要病理特征。     

血管外膜在血管成形术后再狭窄中的作用北大核心CSCD

血管成形术是治疗血管狭窄、改善患者生活质量的重要手段。然而血管成形术可能会导致内膜过度增生,血管成形术再狭窄已成为临床严重问题。血管外膜由多种类型细胞组成,与血管成形术后再狭窄密切相关。血管损伤后激活的外膜成纤维细胞(AF)可转化为肌成纤维细胞(MF)并向内膜迁移,同时促进产生各种细胞因子和炎性分子,而AF衍生的活性氧(ROS)引起的氧化应激也会参与血管炎症,这一炎性反应加剧了血管再狭窄。炎性微环境下,祖细胞分化加剧,脂肪细胞功能失调,引起细胞增殖。本文首次综述了几种外膜细胞如AF、炎性细胞、祖细胞和脂肪细胞在血管成形术后血管重构和内膜增殖中的关键作用。     

32P液体球囊血管内照射预防血管成形术后再狭窄

目的 探讨^32P液体球囊血管内近距离照射治疗对防止血管成形术后再狭窄的量效关系及其抑制再狭窄发生的可能机制。方法 27只雌性大白兔据动脉球囊扩张损伤后，实验组(18只)分别给予3、9、18和36Gy^32P液体球囊行内照射治疗，对照组(9只)灌注生理盐水。术后于不同时间点取材，行HE染色、增殖细胞核抗原(PCNA)免疫组织化学染色以及电镜观察血管组织形态学的改变，用计算机图像分析法测量管腔面积和内膜面积。结果 对照组血管内膜明显增生，管腔变狭窄。18Gy组血管壁平滑肌细胞增殖明显受抑，细胞凋亡增加，管腔面积无明显丢失；36GY组血栓形成明显；3和9Gy组均未观察到明显的生物效应。结论 ^32P液体球囊血管内照射可防止血管成形术后再狭窄发生，其机制可能为抑制血管壁平滑肌细胞增殖，促进其凋亡及改善血管重塑形。     

血管内支架成形术治疗椎动脉狭窄

目的 观察血管内支架成形术治疗椎动脉狭窄的短期疗效。方法 将球囊扩张性支架通过椎动脉狭窄部位，扩张球囊释放支架使狭窄部位恢复正常管径。结果 45例药物治疗无效的表现为后循环缺血症状的患者，43例成功的采用支架成形术，术前术后平均狭窄程度分别为75．7％和10．3％。临床随访35例症状完全缓解，4例明显好转，2例症状无改善。无一例发生内膜撕裂或血栓栓塞形成，短期随访未发现有再狭窄及内膜过度增生。结论 血管内支架成形术是治疗椎动脉狭窄的有效方法，长期疗效需进一步的随访观察。     

主动脉血管支架置入术后再狭窄的相关试验研究

目的:研究在正常小型猪主动脉置入自膨式血管内支架(ES)后再狭窄形成的机制及行经皮血管成形术(PTA)的可行性.材料和方法:中华小型猪7只.1只为预实验组,行血管造影后处死.6只为实验组并随机分为3组,均于主动脉弓降部置入血管内支架.组1和组2、3分别于术后3个月及3、6个月行血管造影;其中组3术后6个月对狭窄行经皮血管成形术.结果:血管内支架均成功置入实验组主动脉弓降部.术后6个月生长发育所致平均狭窄百分面积为6.60±3.55%,内膜增殖所致平均狭窄百分面积为14.61±0.37%.术后第6个月血管内支架置入处前后收缩期压差为1.76±0.37 kPa,行球囊扩张术后压差消失.结论:自膨式血管内支架置入小型动物主动脉可因其生长发育造成再狭窄,并随时间推移加重.行经皮血管成形术疗效满意.     

实验性血管成形术后狭窄变化的动态观察

目的 建立球囊成形术后动脉狭窄的简易动物模型，观察成形术后血管壁各部分变化在动脉狭窄发生中的作用。材料与方法 用2F Fogarty球囊导管损伤大鼠左颈动脉，分别在8周内不同时间点获取标本，利用光镜和电镜研究动脉球囊损伤后的形态变化，另选取2周组和1个月组动物于造模前、造模后进行DSA和MRI检查。结果 (1)光镜与电镜表现：损伤后内皮细胞剥脱，血小板及单核细胞附着，中膜平滑肌细胞坏死和增殖，平滑肌细胞由收缩表型转变为合成表型以及随后的内膜平滑肌细胞出现与复制，弹力纤维、胶原和蛋白成分等细胞外基质的堆积导致内膜明显增厚，管腔狭窄。(2)影像学表现：DSA及MRI均清楚反映出造模后的模型动脉狭窄变化。结论 大鼠球囊损伤模型能较好地反映球囊损伤后血管的病理变化过程且经济、简便易行，应是初筛研究的首选模型；DSA、MRI是监测模型血管动态变化的较好方法。     

血管内放射治疗对平滑肌细胞增殖与凋亡的影响

目的：观察血管内放射治疗（简称放疗）对受损动脉平滑肌细胞（SMC）增殖与凋亡的影响。方法：用^192Ir后装源对猪受损髂动脉进行不同剂量血管内放疗，通过免疫组织化学增殖细胞核抗原（PCNA）与三磷酸脱氧尿嘧啶缺口末端标记法（TUNEL）检测不同时间点血管SMC增殖与凋亡情况。结果：放疗组第3天起中膜SMC增殖明显受抑及凋亡增加（P均＜0．05）；第10天时内膜SMC增殖明显减弱，20Gy组内膜SMC凋亡率显著增加；第28天时内膜SMC增殖明显受抑，凋亡率增加（P均＜0．05），20Gy组较10Gy组明显（P＜0．05）。结论：血管内放疗可抑制动脉损伤后SMC增殖、促进SMC凋亡。     

血管重塑对大鼠血管成形术后再狭窄的影响

目的：建立大鼠颈动脉再狭窄模型，原位灌注固定取材。评价PTA后血管重塑（VR）的动态变化规律，定量分析血管重塑在血管再狭窄过程中的变化及作用。方法：制作70只SD雄性大鼠颈总动脉再狭窄模型，分原位灌注实验组、对照组，于术后1h、3、7、14、28和42天原位灌注固定取材，行HE染色、Masson染色，观察标本血管狭窄情况。结果：①血管重塑指数（VRI）在PTA后即刻最大，3天组明显降低，7天组稍有增大，其后不断减小，剩余血管腔面积百分比同VRI的变化曲线基本一致。②FFA后，血管腔面积总体呈逐渐缩小趋势，内弹力板围绕面积（IELA）1h组较对照组明显增大，3天组较1h组明显缩小，14、28、42天组较对照组明显缩小。外弹力板围绕面积（EELA）逐渐缩小。EELA、IELA的变化与血管腔面积变化呈正相关。③VRI与血管腔面积的变化呈正相关，新生内膜面积与剩余狭窄率、血管腔面积无直线相关。结论：再狭窄过程中存在扩张性重塑和收缩性重塑现象，管腔的狭窄与否取决于血管重塑指数的变化，而不是新生内膜的变化，新生内膜的形成是血管重塑过程中的一部分。IELA和EELA可作为判断管腔狭窄及评价血管重塑的指标。     

~(103)Pd支架预防血管成形术后再狭窄的实验研究

目的　探讨1 0 3 Pd支架对血管成形术后再狭窄的预防作用。方法　对雄性新西兰白兔进行腹主动脉球囊拉伤后置入1 0 3 Pd支架和普通支架 ,各 2 5只实验兔。 2组分别于术后 3d、1、2、4和8周分批用γ计数器进行血管组织和静脉血放射性测定、免疫组织化学测定、组织病理学和血管造影检查。结果　拉伤后 8周造影显示 ,1 0 3Pd支架组血管最小内径显著大于普通支架组 (P <0 0 1) ,血管狭窄程度明显减低 (P <0 0 5 ) ;各亚组间静脉血的放射性无差异 ;2组支架周围组织放射性无统计学差异。结论　1 0 3 Pd支架较普通支架可以显著减少血管成形术后再狭窄的形成 ,1 0 3Pd作为放射源安全和有效     

颈动脉球囊扩张再狭窄动物模型的建立

目的　探索再狭窄的发病机制进行干预研究 ,建立颈动脉再狭窄家兔动物模型。方法　取颈部正中切口 ,无菌暴露兔右颈动脉 ;在颈内动脉 (ICA)起始部及颈总动脉 (CCA)近心侧距动脉分叉2cm处用动脉夹临时夹闭 ;自颈外动脉 (ECA)远端结扎并由结扎近心侧穿刺进入导丝、球囊导管 ,撤除CCA动脉夹进行球囊扩张血管成形术 (PTA)。于PTA后不同时间进行组织学及形态学分析 (左侧颈总动脉作正常对照组 )。结果　PTA后早期CCA主要病理改变是血栓形成 ,中晚期为血管平滑肌细胞(VSMC)由中层移行之内膜并失控增殖伴有基质增多 ;第 15天管腔出现明显狭窄 (P <0 .0 1)内膜增厚(P <0 .0 1)。结论　家兔颈总动脉PTA模型模拟了临床过程 ,成功率高 ,为PTA之动脉阶段局部用药或转基因治疗实验首选模型     

Transluminal angioplasty evaluated by electron microscopy

To gain more understanding about the changes that follow balloon angioplasty, an electron and light microscopic study was carried out in normal canine arteries. Thirty-five arterial segments were dilated with balloon catheters. Early changes consisted of denudation of the intima with widespread necrosis of myocytes and dehiscence of collagen fibers. After three days, myocytes had disappeared leaving empty spaces and edematous ground substance. After two weeks, reendothelization occurred and there was evidence of intimal hyperplasia persisting up to two months. Repair of the dilated arterial segments occurred by proliferation of myocytes, formation of intima, and proliferation of collagen. In two to three months, repair of the intima and media was completed. After six months, dilated segments were characterized by persistent intimal hyperplasia and increased collagen content in the media.     

Atherosclerotic rabbit iliac arteries: comparison of balloon angioplasty and laser-assisted balloon angioplasty.

The effects of balloon angioplasty (BA) and laser-assisted balloon angioplasty (LABA) on arteries were compared. Atherosclerosis was induced in the iliac arteries of New Zealand White rabbits by means of balloon denudation and a diet supplemented with 1% cholesterol and 3% peanut oil. Six weeks later, one iliac artery was dilated with a 2.5- or 3.0-mm-diameter balloon. The contralateral iliac artery was treated with a 1.5-mm-diameter laser probe heated with 6 W of argon laser energy, and then BA was performed. Four weeks later, the mean luminal diameter of the LABA-treated arteries was smaller than that of the BA-treated arteries (BA, 1.57 mm +/- 0.15; LABA, 0.82 mm +/- 0.19; P less than .01). This restenosis was due to greater intimal fibrocellular proliferation (intimal area: BA, 0.83 mm2 +/- 0.16; LABA, 1.41 mm2 +/- 0.26; P less than .05). The LABA-treated arteries produced less potassium chloride-induced maximal force (P less than .01) and had smaller incremental elastic moduli (P less than .05) than did the BA-treated arteries. LABA is not the treatment of choice for small-caliber arteries, in which thermal injury to the arterial wall would be significant.     

血管内放射对猪冠状动脉球囊损伤后细胞增殖和凋亡的影响

探讨血管内放射抑制冠状动脉内介入治疗后再狭窄的机制。通过小型太动脉球囊扩张术后再狭窄动物模型,采用免疫组织化学方法,观察了血管内放射治疗对细胞增殖和细胞凋亡的影响。发现血压血管内放射抑制了球囊扩张术后３天血管外膜和中膜的细胞增殖,同时也抑制了术后３０天血管内膜细胞增殖,但对术后３天和３０天细胞凋亡无显著影响。血管内放射可能通过抑制囊扩张术后早期外膜和中膜以及晚期内膜的细胞增殖而预防再狭窄。     

2005 Dr. Gary J. Becker Young Investigator Award: periprocedural oral administration of the leflunomide analogue FK778 inhibits neointima formation in a double-injury rat model of restenosis

PURPOSE: To test the efficacy of limited oral administration of the new leflunomide analogue FK778 for suppression of neointima proliferation in a double-injury restenosis model in the rat. MATERIALS AND METHODS: For induction of aortic lesions, silicon cuffs were placed operatively around the infrarenal aortas of Lewis rats. After 21 days, the aortic cuffs were removed and the lesions were dilated with 2-F Fogarty catheters inserted via the left common carotid artery. The novel immunosuppressant FK778 was administered at a dose of 5 mg/kg body weight (group 1) or 15 mg/kg body weight (group 2) in a total of 38 animals. For both doses, three different periinterventional time periods, each with a 5-day course of oral FK778, were defined as follows: (i) days -2 to 2, (ii) days 1-5, and (iii) days 7-11, with six or seven rats in each group. After 3 weeks, intima/media ratios were assessed morphometrically and immunohistochemistry for quantification of intimal alpha-actin expression was performed. RESULTS: In both dose groups, there was a trend toward inhibition of neointima formation when the 5-day course of FK778 was started before or 1 day after the intervention. However, in the lower-dose group, inhibition of neointima was not statistically significant regardless of the time frame of treatment (groups 1a-c). With the higher dose, suppression of intimal hyperplasia was significant when FK778 was administered between days 1 and 5 after angioplasty (group 2b; P<.01). Expression of alpha-actin in the intima of FK778-treated rats was significantly reduced when the drug was started 2 days before angioplasty in group 1a (P<.05) or 1 day after angioplasty in both dosage groups (group 1b, P<.01; group 2b, P<.05). CONCLUSION: In the double-injury rat model presented, balloon-mediated proliferation of smooth muscle cells in the intima with consecutive intimal thickening was influenced by FK778 in a dose-dependent manner. However, long-term studies are needed to exclude a delay of vascular healing in this particular model.     

Increased expression of nuclear NF-kappaB after coronary artery balloon injury can be inhibited by intracoronary beta-irradiation

PURPOSE: Molecular mechanisms by which balloon angioplasty injury-induced neointimal hyperplasia can be reduced by intravascular brachytherapy are unclear. We investigated the role of nuclear factor-kappaB (NF-kappaB) in neointimal hyperplasia following intracoronary irradiation. MATERIALS AND METHODS: Fifty-four coronary arteries from 30 pigs were divided into 6 groups: sham control, balloon angioplasty injury alone, beta-irradiation at doses of 14 or 20 Gy, and 14 or 20 Gy beta-irradiation immediately followed by balloon injury. Coronary arteries were injured by overstretch balloon angioplasty and then the arteries were irradiated using a Rhenium-188 ((188)Re) beta-emitting solution-filled balloon. Pigs were scarified one day or one week after coronary interventions for molecular detection and six weeks after the procedures for histological examination. RESULTS: Six weeks after coronary interventions, the histological results show that balloon angioplasty injury had induced intimal hyperplasia in coronary artery but the response was significantly reduced by 28% and 60% when the injury was immediately treated by 14 and 20 Gy (188)Re beta-irradiation, respectively. The expression of arterial NF-kappaB p65, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were detected at one day and one week after the procedures. The treatment of balloon injury could significantly induce the NF-kappaB p65 expression in both gene and protein levels, and such induction could be significantly reduced by (188)Re beta-irradiation at dose of 20 Gy. However, the similar result on the regulation of gene expression affected by the beta-irradiation could not be observed in ICAM-1 and VCAM-1. CONCLUSION: The inhibitory effect of intracoronary brachytherapy on neointimal formation following overstretch balloon angioplasty could involve inhibition of NF-kappaB p65.     

Complete inhibition of intimal hyperplasia by perivascular delivery of paclitaxel in balloon-injured rat carotid arteries

PURPOSE: To determine whether perivascular delivery of paclitaxel prevents luminal narrowing after balloon injury by inhibiting intimal hyperplasia. MATERIALS AND METHODS: Immediately after balloon injury of the entire left common carotid artery, three slow-release formulations of paclitaxel or control formulations without drug were applied around a distal segment of the artery. The noninjured right carotid arteries were evaluated as a control. The animals were maintained for 14 and 28 days (n = 5 in each group at each time interval). Histology, immunohistochemistry, and morphometric analysis were performed. RESULTS: Injured nontreated arteries exhibited a pronounced intimal hyperplasia (0.185 +/- 0.01 mm2 at 14 days and 0.189 +/- 0.01 mm2 at 28 days) and a marked reduction in luminal area (44% at 14 days and 43% at 28 days). Medial area and the number of medial cells increased by 44% and 45%, respectively, at 14 days, and by 22% and 37%, respectively, at 28 days. Injured arteries treated with perivascular paclitaxel did not show any intimal hyperplasia, and luminal area was increased in five of six groups and was unchanged in one group. These arteries had an increased medial area but they had fewer medial cells than noninjured arteries. Injured arteries treated with control implants without paclitaxel exhibited intimal hyperplasia and luminal narrowing. CONCLUSION: Perivascular slow release of paclitaxel totally inhibits intimal hyperplasia and prevents luminal narrowing after balloon injury. Because of its efficacy, perivascular paclitaxel represents a possible approach for prevention of restenosis in humans.