SM22α抑制球囊损伤诱导的新生内膜形成

观察外源性SM22α对球囊损伤诱导的大鼠颈总动脉新生内膜形成的影响,并探讨其机制。雄性SD大鼠经球囊剥脱颈总动脉内皮后随机分为3组:未感染组、pAd组和pAd-SM22α组。术后14天取颈总动脉标本,HE染色观察血管内膜增生情况,用Western blot和免疫组化方法检测外源性SM22α、PCNA和p27在血管壁中的表达水平,以及Raf-1、MEK1/2和ERK1/2的磷酸化水平。实验结果显示,外源性SM22α在血管壁中得到稳定表达;过表达SM22α可显著抑制球囊损伤诱导的血管新生内膜的增厚,与pAd组比较,内膜/中膜比值(I/M)降低70%;Western blot结果显示,在pAd-SM22α组中增殖标志物PCNA表达水平降低(P0.05),而增殖抑制蛋白p27表达水平增高(P0.05),同时伴有增殖相关信号转导分子Raf-1、MEK1/2和ERK1/2的磷酸化水平降低(P0.05)。结果提示,过表达SM22α可抑制球囊损伤诱导的血管内膜增生,其机制可能与阻断Raf-1-MEK1/2-ERK1/2通路的级联活化有关。     

17-AAG对大鼠颈总动脉球囊损伤后内膜增生的影响及其作用机制

目的:研究17-丙烯胺-17去甲氧格尔德霉素(17-Allylamino-17-emethoxy-geldanamycin, 17-AAG)对球囊损伤后大鼠颈总动脉内膜增生的影响及可能作用机制。方法:将清洁级雄性SD大鼠36只按照随机数字法分为假手术组(Sham组)12只、球囊损伤组(Balloon injury, BI组)12只及17-AAG治疗组(17-AAG组)12只。采用2F Fogarty球囊建立大鼠颈总动脉球囊损伤组模型,17-AAG治疗组大鼠在建模后腹腔注射17-AGG(20 mg/kg 2d)。各组大鼠于球囊损伤3周后取损伤段颈总动脉,通过HE染色观察血管内膜形态学改变并评估内膜增生情况,免疫组化染色(Immunohistochemical staining,IHS)法检测血管壁增殖细胞核抗原(Proliferating cell nuclear antigen,PCNA)的表达,评估血管平滑肌细胞的增殖情况。流式细胞术检测血管平滑肌细胞的凋亡情况。结果:BI组、17-AAG组大鼠球囊损伤后颈总动脉内膜出现不同程度增生,内膜/中膜面积比(Intima area/Membrane area,I/M)均较Sham组显著升高(P0.05);17-AAG组的I/M较BI组明显下降(P0.05)。BI组、17-AAG组颈总动脉PCNA表达水平较Sham组明显升高(P0.05),较BI组显著降低(P0.05)。BI组、17-AAG组大鼠血管平滑肌细胞凋亡率较Sham组显著升高(P0.05);17-AAG组大鼠血管平滑肌细胞凋亡程度较BI组明显升高(P0.05)。结论:17-AAG对球囊损伤后颈总动脉内膜增生存在抑制作用,其机制可能是通过提高血管平滑肌细胞凋亡率影响其增殖程度。     

Egr-1的诱骗性寡脱氧核苷酸抑制大鼠颈总动脉损伤后MMP-2的表达

目的观察局部转染早期生长反应因子-1(early growth response factor-1,Egr-1)的特异诱骗寡脱氧核苷酸(decoy oligodeoxynucleotides,decoy ODNs)对球囊损伤颈总动脉后基质金属蛋白酶-2(MMP-2)蛋白表达的影响及内膜增生的情况,初步探讨Egr-1,decoy ODNs抑制球囊损伤后内膜增生的机制。方法 96只健康雄性Wistar大鼠,随机分为4组,分别为假手术组、对照组、杂码组和诱骗组,每组24只。除假手术组外均应用2F球囊导管行颈总动脉球囊损伤术,术中采用转染试剂FuGENE6介导的Egr-1decoy ODNs转染至损伤后大鼠血管中,与假手术组、对照组、杂码组相比较。术后3、7、14、21d每组处死6只动物。应用HE染色和免疫组织化学方法观察大鼠颈总动脉球囊损伤后内膜增生情况和MMP-2蛋白的表达及转染Egr-1decoy ODNs后对它们的影响。结果 (1)、内膜损伤后3d内膜增厚不明显,7d内膜开始增厚,14、21d时内膜明显增厚。(2)、在假手术组近腔面中膜可见MMP-2有少量散在阳性表达;在对照组及杂码组动脉损伤后3d,在近腔面中膜,有少量阳性表达,与假手术组相比,阳性表达指数上升。7d时在新生内膜和靠近新生内膜处中膜表达明显,14d后表达逐渐下降。(3)转染decoy ODNs治疗后,在各个时间点内膜增厚程度减轻,MMP-2蛋白表达减少,与对照组比较差异有显著性(P<0.01)。结论血管球囊损伤后,内膜7d开始增生,14d、21d增生更明显,而MMP-2在7d时表达明显,之后逐渐下降,Egr-1decoy ODNs能抑制MMP-2的表达,从而减轻血管损伤后内膜的增生。     

17-AAG 对颈动脉球囊损伤大鼠血管平滑肌细胞增殖影响的实验研究

目的：研究17- 丙烯胺-17 去甲氧格尔德霉素（17-Allylamino-17-emethoxy-geldanamycin, 17-AAG）对球囊损伤后大鼠颈动脉 血管平滑肌细胞增殖的影响。方法：选取雄性Sprague-Dawley（SD）大鼠30 只,随机数字法分为球囊损伤（Balloon injury,BI）组10 只、球囊损伤+17-AAG 低剂量治疗（Balloon injury+Low dose AGG,BIL）组10 只、球囊损伤+17-AAG 高剂量治疗（Balloon injury+High dose AGG,BIH）组10只。建立大鼠颈动脉球囊损伤模型,病理学评估血管内膜增生情况。各组于球囊损伤28 天后取 材,将损伤区域的血管段取材固定,苏木精- 伊红染色（HE）观察血管并测量内膜面积（Intimal Area, IA）、中膜面积（Membrane Area,MA）,计算内膜/中膜面积比（IA/MA）,以评估内膜增生情况;同时,利用免疫荧光染色（Immunofluorescence staining, IFS）观 察增殖细胞核抗原（Proliferating cell nuclear antigen, PCNA）表达的情况,以评价血管平滑肌细胞的增殖情况。结果：大鼠颈动脉球 囊损伤模型成功建立。HE 染色后计算血管I/M比值,结果表明BIL组与BI组血管I/M 比值无统计学差异（P>0.05）,BIH 与BI组 血管I/M比值有统计学差异（P<0.05）。IFS结果表明,BIL组血管壁PCNA 表达较BI组略有降低,但无统计学意义（P>0.05）。BIH 组血管壁PCNA表达较BI组明显减低,有显著统计学差异（P<0.05）。结论：一定浓度的17-AAG可明显的抑制球囊损伤后颈动脉 血管平滑肌细胞增殖;17-AAG可以成为球囊损伤后大鼠血管平滑肌细胞增殖的抑制剂。     

早期生长反应因子-1的特异脱氧核酶对球囊损伤大鼠颈动脉后转化生长因子-β1表达的影响

目的观察局部转染早期生长反应因子-1(Egr-1)的特异脱氧核酶(ED5)对球囊损伤颈总动脉后内膜增生及转化生长因子-β1(TGF-β1)表达的影响,并初步探讨ED5抑制球囊损伤后内膜增生的机制。方法96只健康雄性Wistar大鼠,随机分为4组,每组24只。除假手术组外均应用2F球囊导管行颈总动脉内膜球囊损伤术,术中采用转染试剂FuGENE6介导ED5转染至损伤后大鼠血管中,以假手术组、单纯损伤组,FuGENE6组作为对照。术后3、7、14、21d处死动物每组6只。应用HE染色,RT-PCR,Western-blot和免疫组织化学方法观察大鼠颈动脉球囊损伤后内膜增生情况和TGF-β1的表达及ED5对它们的影响。结果(1)内皮损伤后3d内膜增厚不明显,7d内膜开始增厚,14、21d时内膜明显增厚。(2)TGF-β1mRNA于术后3d开始升高,7d达高峰,14d时下降。TGF-β1蛋白表达于术后3d开始升高,14d达高峰。(3)转染ED5治疗后,在各个时间点内膜增厚程度减轻,TGF-β1表达减少,与对照组比较差异有显著性(P<0·01)。结论血管内皮损伤后内膜增生过程中TGF-β1表达增加,ED5能抑制TGF-β1的表达,从而减轻血管损伤后内膜的增生。     

Egr-1的特异性脱氧核酶对大鼠颈总动脉损伤后内膜增生的影响

目的 探讨早期生长反应因子-1(Egr-1)的特异性脱氧核酶对大鼠颈总动脉损伤后新生内膜形成的影响。方法 对Wistar大鼠行颈总动脉损伤后,在转染试剂Fugene6介导下经血管腔内转染Egr-1的特异性脱氧核酶(ED5),以假手术组、单纯损伤组及空白转染试剂组(Fu gene 6组)作为对照,于术后3、7、14和21d4个时间点取材,检测内膜增生程度及增殖细胞核抗原(PCNA)、转化生长因子-β(TGF-β)和Egr-1的表达变化。结果单纯损伤组及Fugene6组7d时可见内膜增生,14d、21d时内膜增厚更明显,PCNA及TGF-β于损伤后3天明显表达,7d时在新生内膜及中膜中表达达到高峰,14d后逐渐下降,而Egr-1呈持续高表达。经ED6作用后,内膜增生减轻,动脉中PCNA、TGF-β及Egr-1表达明显降低,与单纯损伤组和Fu Gnene 6组比较差异有显性。结论结果提示ED5可能是通过特异性抑制其相应基因的表达来阻遏动脉损伤后的内膜增生。     

旋覆花素抑制血管内皮损伤诱导的基质重构酶表达与活化

目的：观察旋覆花素对大鼠血管球囊损伤后内膜增生和基质金属蛋白酶-2（MMP-2）及组织金属蛋白酶抑制剂-2（TIMP-2）表达的影响,探讨旋覆花素防治血管再狭窄的可能作用和机制。方法：用球囊内皮剥脱法复制血管内膜增生模型 通过HE染色观察血管壁形态学变化 明胶酶图分析MMP-2的活性改变 Western blot和免疫组织化学检测MMP-2和TIMP-2的表达变化。结果：旋覆花素显著减轻血管损伤后内膜增生,抑制MMP-2的蛋白水解活性,降低MMP-2和TIMP-2的表达以及MMP-2/TIMP-2比值,并使其接近正常水平。结论：旋覆花素对球囊血管损伤后内膜增生的抑制作用与其对MMP-2/TIMP-2系统平衡调节有关。     

二苯乙烯苷抑制NADPH氧化酶对小鼠脑缺血/再灌注损伤的保护作用

目的探讨二苯乙烯苷(TSG)抑制NADPH氧化酶对小鼠脑缺血再灌注(I/R)损伤的保护作用。方法将100只实验小鼠随机分成5组:假手术组、模型组,TSG低剂量组(3 mg/kg),TSG中剂量组(6 mg/kg),TSG高剂量组(12 mg/kg),每组20只。通过双侧颈总动脉结扎造成小鼠脑缺血2 h,再灌注24 h后处死小鼠。采用HE染色法对小鼠脑组织进行病理学检测,采用DHE染色法和ESR波谱仪检测脑组织中活性氧(ROS)水平,采用Western blot法检测脑组织中NOX4和cleaved caspase-3/9蛋白的表达。结果小鼠脑缺血再灌注后,缺血区皮层脑组织出现严重的病理性损伤,其ROS水平显著升高,脑组织中NOX4蛋白表达显著上调,凋亡相关蛋白cleaved caspase-3/9蛋白表达量显著增加。TSG可以显著减轻小鼠缺血再灌注脑组织的病理性损伤,抑制ROS的产生,显著下调氧化应激蛋白NOX4的表达,并显著抑制凋亡相关蛋白cleaved caspase-3/9蛋白的表达。结论 TSG可通过抑制脑组织氧化应激蛋白NOX4的表达,减少活性氧的生成,并抑制凋亡相关蛋白cleaved caspase-3/9过度表达,对小鼠脑缺血再灌注损伤起保护作用。     

旋覆花素抑制血管内皮剥脱诱导的粘附分子表达

目的观察旋覆花素对内皮剥脱诱导的新生内膜形成过程中血管壁粘附分子OPN、ICAM-1、ILK表达的影响,为寻找该药物抑制新生内膜形成的作用靶标提供实验依据。方法采用主动脉球囊损伤后血管狭窄动物模型,用免疫组织化学和Western Blot方法分别检测血管壁中骨桥蛋白(osteopontin,OPN)、细胞间粘附分子-1(intercellular adhesion molecule-1,ICAM-1)、整合素偶联激酶(integrin-linked kinase,ILK)的表达变化及旋覆花素对其的影响。结果血管内皮剥脱可诱导血管壁平滑肌细胞大量增生,新生内膜呈弥漫性增厚,血管损伤局部组织中OPN、ICAM-1、ILK的表达均比正常对照组明显升高(P<0.05)。旋覆花素治疗组在球囊损伤后,血管内膜增生程度显著减轻,血管壁OPN、ICAM-1、ILK的表达均比模型组明显降低(P<0.05)。结论旋覆花素减缓新生内膜形成的效应与其抑制粘附分子的表达、阻断粘附分子信号传递有关。     

AT2R载体可调控表达对大鼠颈动脉损伤后骨桥蛋白及新生内膜增生的影响

目的:血管紧张素Ⅱ 2型受体(AT2R)基因转染的骨髓间充质干细胞(MSC)在四环素可调控系统下作为载体,利用计算机图像分析系统研究新生内膜增生的情况,并探讨AT2R在体可调控表达对大鼠颈动脉损伤后骨桥蛋白(OPN)表达影响。方法:利用球囊损伤60只SD大鼠颈动脉,并随机将SD大鼠分为5组,分别为正常组(未行球囊扩张术)、对照组(球囊扩张术后注入PBS)、MSC组(球囊扩张术后注入常规MSC)、MSC转染组(球囊扩张术注入转染AT2R的MSC)、强力霉素(Dox)组(球囊扩张术后注入转染AT2R的MSC,术后当天至处死前三天通过尾静脉注射Dox 100μg/kg/d)。术后14及28天分别处死大鼠取材,光镜下观察血管内膜增生情况,Image pro plus 6.0计算机图像分析系统测量新生内膜面积(I/M),逆转录-多聚酶链反应(RT-PCR)检测AT2R及OPN在大鼠血管标本中的表达变化。结果:大鼠颈动脉AT2R在Dox组的表达显著增高,新的增生内膜面积较其它各损伤组显著降低(P≤0.01),并且OPN的表达显著低于其他各手术组。结论:AT2R基因在体可调控表达受到Dox的有效控制,AT2R基因可能抑制血管损伤后OPN的表达及新生内膜的过度增生。     

Electrical stimulation inhibits neointimal hyperplasia after abdominal aorta balloon injury through the PTEN/p27Kip1 pathway

Electric fields (EFs) exert biological effects on promoting wound healing by facilitating cell division, cell proliferation, and cell directional migration toward the wound. In this study, we examined the inhibitory effect of direct-current (DC) EFs on the formation of neointimal hyperplasia and the possible mechanism in an abdominal aorta balloon injury rabbit model. Sixty rabbits were divided into normal, control, and experimental groups. After establishment of the abdominal aorta balloon injury model, electrodes were implanted into the bilateral psoas major muscle in control and experimental groups. Only the experimental group received electric stimulation (EFs applied at 3 or 4 V/cm for 30 min/day) for 1, 2, and 4 weeks, respectively. Neointimal hyperplasia of the abdominal aorta and proliferation of vascular smooth muscle cells (VSMCs) were measured. Expressions of collagen, p27(Kip1), and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) were detected. Results showed that the ratio of the tunica intima area to the tunica media area, the expression of type-I collagen in the neointimal, and the proliferating cell nuclear antigen index in experimental groups were significantly less than those in control groups 2 weeks post-operation (P< 0.01). Expressions of p27(Kip1) and PTEN were increased in experimental groups compared with control groups (P< 0.01). In conclusion, our results suggested that the application of DC EFs could inhibit neointimal hyperplasia and reduce collagen expression after abdominal aorta balloon injury. This was probably induced by upregulation of PTEN/p27(Kip1) expression, thereby inhibiting VSMC proliferation.     

Long period of balloon inflation and the implantation of stents potentiate smooth muscle cell death. Possible role of chronic vascular injury in restenosis

BACKGROUND: It has been suggested that the severity of acute vascular injury immediately after percutaneous transluminal coronary angioplasty (PTCA) or stent implantation correlates with the extent of neointimal hyperplasia and restenosis. However, the influence of prolonged or chronic vessel injury on the pathogenesis of restenosis is unclear. METHODS: Rabbit iliac arteries were balloon dilated for a short (1 min) or prolonged (10 min) period of time, or were chronically dilated and received a Palmaz-Schatz stent (balloon inflation for 1 min). All arteries were overexpanded to a balloon:artery ratio of 1.2:1 as determined by angiography. The arteries were removed 30 min and 4 weeks after the angioplasty procedures. The sites of injury were evaluated by gross histology and transmission electron microscopy (TEM). Cell death of medial smooth muscle cells (SMCs) was specified by TEM images 30 min after the procedures. Computer-assisted quantification of the neointimal cross-sectional areas was performed after 4 weeks using a light microscope connected to a digital image analyser. RESULTS: The results show that prolonged balloon dilatation and stent implantation increased necrotic SMC death compared with balloon dilatation for 1 min. After 30 min, increased staining of SMC nuclei, enlarged intercellular spaces and changes in SMC shape in the media indicated cell death induced by prolonged balloon dilatation or chronic stent injury. Stent implantation markedly augmented vessel damage by persistent compression of the media, compared with a balloon dilatation for 1 or 10 min. Both prolonged balloon dilatation and stent implantation increased neointimal hyperplasia at 4 weeks compared with balloon dilatation for 1 min (0.6 3 0.2 and 1.0 3 0.2 mm(2) versus 0.2 3 0.1 mm(2), P < 0.001 versus dilatation for 1 min). CONCLUSION: Prolonged or chronic vascular expansion due to long balloon-inflation periods or the implantation of stents increases medial SMC death, which subsequently stimulates neointimal growth in this restenosis model. Chronic vascular injury may be an important stimulus for restenosis after angioplasty procedures.     

Salvia miltiorrhiza inhibits intimal hyperplasia and monocyte chemotactic protein-1 expression after balloon injury in cholesterol-fed rabbits

Antioxidants that prevent low density lipoproteins (LDL) from oxidation may inhibit atherosclerosis and post-angioplasty restenosis. Salvia miltiorrhiza (SM) has been shown to inhibit LDL oxidation and reduce atherosclerosis in cholesterol-fed rabbits. The effects of SM on neointimal hyperplasia and monocyte chemotactic protein-1 (MCP-1) expression after balloon injury were studied. Male New Zealand white rabbits were fed a 2% cholesterol diet together with daily SM (4.8 gm/kg body wt.) treatment (SM; n=10) or without SM as a control (C; n=9) for 6 weeks. Probucol-treated (0.6 gm/kg body wt.) rabbits (P; n=9) were used as a positive control group. A balloon injury of the abdominal aorta was performed at the end of the third week. Aortas were harvested at the end of 6 weeks. The plasma cholesterol levels were lowered in SM group. The neointimal hyperplasia in abdominal aortas was significantly inhibited in SM group [neointima/media area ratio: 0.63+/-0.05 (SM) versus 0.78+/-0.05 (C); P < 0.05] and in P group [0.45+/-0.02 (P) versus 0.78+/-0.05 (C); P < 0.05] when compared with C group. SM treatment significantly reduced MCP-1 mRNA and protein expression in balloon-injured abdominal aorta. These inhibitory effects on intimal response after balloon injury might be attributed to antioxidant capacity and cholesterol lowering effect of SM. SM treatment may offer some protection against post-angioplasty restenosis.     

Vanin-1 pantetheinase drives smooth muscle cell activation in post-arterial injury neointimal hyperplasia

The pantetheinase vanin-1 generates cysteamine, which inhibits reduced glutathione (GSH) synthesis. Vanin-1 promotes inflammation and tissue injury partly by inducing oxidative stress, and partly by peroxisome proliferator-activated receptor gamma (PPARγ) expression. Vascular smooth muscle cells (SMCs) contribute to neointimal hyperplasia in response to injury, by multiple mechanisms including modulation of oxidative stress and PPARγ. Therefore, we tested the hypothesis that vanin-1 drives SMC activation and neointimal hyperplasia. We studied reactive oxygen species (ROS) generation and functional responses to platelet-derived growth factor (PDGF) and the pro-oxidant diamide in cultured mouse aortic SMCs, and also assessed neointima formation after carotid artery ligation in vanin-1 deficiency. Vnn1(-/-) SMCs demonstrated decreased oxidative stress, proliferation, migration, and matrix metalloproteinase 9 (MMP-9) activity in response to PDGF and/or diamide, with the effects on proliferation linked, in these studies, to both increased GSH levels and PPARγ expression. Vnn1(-/-) mice displayed markedly decreased neointima formation in response to carotid artery ligation, including decreased intima:media ratio and cross-sectional area of the neointima. We conclude that vanin-1, via dual modulation of GSH and PPARγ, critically regulates the activation of cultured SMCs and development of neointimal hyperplasia in response to carotid artery ligation. Vanin-1 is a novel potential therapeutic target for neointimal hyperplasia following revascularization.     

Bone marrow-derived mesenchymal stem cells inhibit vascular smooth muscle cell proliferation and neointimal hyperplasia after arterial injury in rats

We investigated whether mesenchymal stem cell (MSC)-based treatment could inhibit neointimal hyperplasia in a rat model of carotid arterial injury and explored potential mechanisms underlying the positive effects of MSC therapy on vascular remodeling/repair. Sprague-Dawley rats underwent balloon injury to their right carotid arteries. After 2 days, we administered cultured MSCs from bone marrow of GFP-transgenic rats (0.8 × 10⁶ cells, n = 10) or vehicle (controls, n = 10) to adventitial sites of the injured arteries. As an additional control, some rats received a higher dose of MSCs by systemic infusion (3 × 10⁶ cells, tail vein; n = 4). Local vascular MSC administration significantly prevented neointimal hyperplasia (intima/media ratio) and reduced the percentage of Ki67 + proliferating cells in arterial walls by 14 days after treatment, despite little evidence of long-term MSC engraftment. Notably, systemic MSC infusion did not alter neointimal formation. By immunohistochemistry, compared with neointimal cells of controls, cells in MSC-treated arteries expressed reduced levels of embryonic myosin heavy chain and RM-4, an inflammatory cell marker. In the presence of platelet-derived growth factor (PDGF-BB), conditioned medium from MSCs increased p27 protein levels and significantly attenuated VSMC proliferation in culture. Furthermore, MSC-conditioned medium suppressed the expression of inflammatory cytokines and RM-4 in PDGF-BB-treated VSMCs. Thus, perivascular administration of MSCs may improve restenosis after vascular injury through paracrine effects that modulate VSMC inflammatory phenotype.     

Cilostazol attenuates MCP-1 and MMP-9 expression in vivo in LPS-administrated balloon-injured rabbit aorta and in vitro in LPS-treated monocytic THP-1 cells

Monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-9 (MMP-9) are involved in vascular inflammation. We tested the hypothesis, and explored the underlining mechanisms that cilostazol, a phosphodiesterase 3 inhibitor with antiplatelet and antithrombotic properties, inhibits lipopolysaccharide (LPS)-induced MCP-1 and MMP-9 expression. In a rabbit aorta balloon-injury model, administration of LPS increased macrophage infiltration and MCP-1 and MMP-9 expression; cilostazol supplementation prevented this phenomenon and reduced intimal hyperplasia. In contrast, the reverse zymography showed that cilostazol did not affect TIMP-1 expression in serum. In monocytic THP-1 cells, cilostazol and N6,O2'-dibutyryl-cAMP (dioctanoyl-cAMP, a cAMP analog) dose-dependently inhibited LPS-induced MCP-1 protein expression and MMP-9 activation, but did not affect the tissue inhibitor of metalloproteinase-1. Quantitative real-time polymerase chain reaction (PCR) showed that cilostazol inhibited MCP-1 and MMP-9 mRNA expression. Cilostazol significantly inhibited LPS-induced activation of p38, JNK, and nuclear factor-kappaB, and the respective inhibitors of p38 and JNK greatly reduced the level of LPS-induced MCP-1 and MMP-9, suggesting the involvement of the p38 and JNK pathways. In conclusion, cilostazol administered with LPS in vivo reduced neointimal hyperplasia and macrophage infiltration in the balloon-injured rabbit aorta; in vitro, cilostazol inhibits LPS-induced MCP-1 and MMP-9 expression. These data suggest that cilostazol may play an important role in preventing endotoxin- and injured-mediated vascular inflammation.     

Porous balloon delivery of S-dC28 does not prevent restenosis in the porcine coronary artery model of balloon injury

Phosphorothioate (PS) oligodeoxynucleotides (ODN) inhibit vascular smooth muscle cell proliferation through antisense and G-quartet aptameric mechanisms. PS-ODN such as the cytidine homopolymers, have been demonstrated to have non-G-quartet, nonsequence-specific inhibitory effects in a rat carotid balloon injury model of neointimal proliferation. We sought to test the efficacy of S-dC28, a cytidine homopolymer lacking G-quartets, on neointimal proliferation in the porcine coronary artery model of balloon injury. A total of 23 animals (11 controls, 12 treated) were subjected to balloon injury in a coronary artery, followed by infusion of control solution or S-dC28 via porous balloon, the Scimed Dispatch Coronary Infusion Catheter. After a mean interval of 49 days, the animals were killed, and the target coronary segments were examined histologically. S-dC28 did not significantly inhibit neointimal formation. Fluorescein isothiocyanate (FITC)-labeled S-dC28 was present in the intima and media immediately after administration but was present mainly within the adventitia 3 hours after administration. S-dC28, when delivered by a Scimed Dispatch Coronary Infusion Catheter (Maple Grove, MN), did not significantly affect neointimal proliferation after balloon injury in a porcine coronary artery model.     

Effects of enalaprilat on neointimal growth of cultured rabbit aorta following balloon injury

Our objective was to determine if the ability of an angiotensin-converting enzyme (ACE) inhibitor to attenuate neointima formation in balloon-damaged vessel is expressed in an isolated organ culture model of neointimal growth. In vivo balloon angioplasty in combination with in vitro organ culture was used to produce a unique model of vascular neointima formation. Aortic segments were cultured in medium containing a broad concentration range of the ACE inhibitor enalaprilat (0-100 microM). Cell proliferative indices and neointima:media thickness ratios were determined from vessel segments after 1, 4, and 7 days in culture. We observed no significant effect on either parameter at any dose of enalaprilat. Linear regression analysis on the rate of increase in intima to media thickness ratios during the 7 days of culture also showed no effect of enalaprilat at any concentration. We conclude that enalaprilat has no effect on neointimal growth or cell proliferation in this vascular organ culture model, and it is suggested that ACE inhibitors may act by mechanisms other than local converting enzyme inhibition to attenuate neointimal growth in rabbits following vascular ballooning in vivo.