昆明山海棠及其提取物对兔血管球囊损伤后内膜增生的抑制作用

目的 探讨昆明山海棠(THH)及其提取物THW-4对兔血管球囊损伤后内膜增生的作用.方法 建立兔颈动脉损伤模型,采用THH中药灌胃及THH中药灌胃/THW-4局部灌注两种给药方式,分别观察用药14 d和28 d后药物对血管新生内膜形成及内皮修复的影响.结果 用药后14 d,增殖细胞核抗原(PCNA)免疫组织化学染色显示, THH灌胃组和联合用药组新生内膜中PCNA染色阳性细胞比率均明显少于对照组(17.68%±5.27%,6.60%±2.52%比40.37%±7.12%,P<0.01);伊文思蓝活体染色显示各组内皮修复差异不明显.用药后28 d血管壁定量组织形态学分析显示,THH灌胃组和联合用药组血管新生内膜面积及内膜面积与中膜面积比均显著低于对照组(2.95±0.65 mm2, 3.49±0.44 mm2比5.25±0.53 mm2;0.53±0.10,0.69±0.10比0.97±0.14,P均<0.01).结论 THH及THW-4可有效抑制血管球囊损伤后血管平滑肌细胞的增殖及新生内膜的形成.     

罗格列酮对大鼠胸主动脉球囊损伤后内皮再生和内膜增生的影响

目的探讨罗格列酮(rosiglitazone,RSG)对血管损伤后内皮再生和内膜增生的影响。方法制备大鼠胸主动脉球囊损伤模型,将SD大鼠随机分为RSG组、对照组和假手术组,于术后第7天和第14天处死动物。分别进行伊文思蓝染色观察内皮覆盖情况,细胞核增殖抗原(PCNA)免疫组化染色和组织形态学定量分析,并测量损伤后14 d时各组血清一氧化氮(NO)含量。结果RSG 7 d组和14 d组的再生内皮覆盖率分别为38.2%和75.2%,均较对照组(32.4%和60.4%)显著增加(P<0.05和P<0.01),且RSG 14 d组血清中的NO含量较对照组升高。球囊损伤后7 d内膜开始有少量增生,14 d时形成明显的新生内膜。RSG使损伤后14 d形成的新生内膜显著减少,内膜面积与中膜面积的比值(IA/MA)较对照组降低60.9%。与对照组比较,RSG 7 d组和14 d组新生内膜内的PCNA阳性表达指数均显著减少。结论RSG可以促进大鼠胸主动脉球囊损伤处的内皮再生,并减少新生内膜的形成。     

体外培养间充质干细胞移植对颈动脉损伤后局部NO含量和eNOS mRNA表达的影响

目的经静脉移植MSCs治疗球囊损伤的粥样硬化颈动脉,探讨MSCs对动脉损伤后修复的影响及可能的作用机制。方法制作颈动脉粥样硬化狭窄动物模型48只,分为MSCs移植组(n=30)和对照组(n=18)。MSCs移植组于球囊损伤前经外周血采集MSCs并体外培养扩增,于球囊损伤后即刻、1周和2周经静脉移植MSCs,而对照组给予等量生理盐水。于球囊损伤后4周收集血管标本,经免疫化学染色后观察血管病理形态学特点、计算新生内膜和中膜面积、检测增殖细胞核抗原(PCNA)以及ELISA法测定局部NO含量和RT-PCR检测eNOSmRNA表达。结果血管病理形态学检测显示,MSCs移植组颈动脉内皮细胞少量缺失,但无内皮的片状剥脱,管壁部分区域轻度增厚,管腔轻度狭窄,增厚处中膜可见少量泡沫细胞沉积,部分区域伴少量纤维组织增生,呈动脉粥样硬化早中期(脂纹-纤维斑块期)改变。与对照组比较,MSCs移植组新生内膜面积(NEA)和中膜面积(MA)均明显减少(P0.05);而两组间新生内膜/中膜面积比(I/M)无统计学意义。同时,血管壁PCNA测定显示:MSCs移植组PCNA阳性细胞率显著低于对照组,表明与移植组相比,对照组新生内膜增生程度更为明显。MSCs移植组损伤的颈动脉局部NO含量和eNOSmR-NA表达均明显高于对照组,差异具有统计学意义。同时,eNOSmRNA表达程度与4周时动脉内膜增生情况相关分析显示呈负相关。结论 MSCs静脉移植可明显降低球囊损伤动脉的新生内膜增生,这可能与损伤动脉局部eNOSmRNA表达和NO含量增加有关。     

骨髓间充质干细胞局部移植对兔腹主动脉成形术后再狭窄和平滑肌细胞增殖的影响

目的探讨兔腹主动脉血管成形术后,骨髓间充质干细胞(BMSCs)移植对兔腹主动脉再狭窄和平滑肌细胞增殖的影响及机制。方法将60只新西兰大白兔随机分为对照组、损伤组、移植组各20只。所有动物均穿刺股动脉,对照组不进行球囊扩张损伤腹主动脉,损伤组和移植组送入球囊扩张损伤腹主动脉,损伤组注射等量的磷酸盐缓冲液(PBS),移植组用经4,6-联脒-2-苯基吲哚(DAPI)荧光标记的BMSCs以1×107/kg的细胞数经血管注射到损伤血管的局部。术后4 w取腹主动脉行免疫组织化学染色检测平滑肌肌动蛋白(α-SM-actin)、增殖细胞核抗原(PCNA)在血管内膜上的表达情况,测定PCNA阳性细胞核数量,计算PCNA增殖指数。HE染色行血管形态计量分析包括内膜中膜厚度、内膜中膜面积,衡量血管狭窄情况。结果损伤组新生血管内膜层α-SM-actin表达明显强于对照组(P<0.05),移植组新生血管内膜α-SM-actin表达,与损伤组比较明显增强(P<0.05)。对照组血管内膜无PCNA阳性表达,损伤组PCNA阳性细胞数较对照组明显增多(P<0.05)。移植组PCNA阳性细胞数较损伤组明显减少(P<0.05)。损伤组腹主动脉明显狭窄,内膜厚度、内膜面积、中膜厚度、中膜面积、血管狭窄程度等指标明显高于移植组和对照组(P<0.05),移植组腹主动脉有所狭窄,但血管形态学指标与对照组比较差异无统计学意义(P>0.05)。结论兔腹主动脉球囊损伤后导致血管平滑肌细胞增殖及动脉管腔狭窄。BMSCs血管局部移植可抑制血管平滑肌细胞的增殖,减轻动动脉粥样硬化及狭窄程度。     

骨髓间充质干细胞移植对兔颈动脉球囊损伤后再狭窄的影响

目的 探讨兔颈动脉行球囊损伤后,骨髓间充质干细胞(BMSC)移植对损伤血管内皮修复和再狭窄的影响.方法 建立兔颈动脉粥样硬化狭窄模型48只,随机分成BMSC移植组24只和对照组24只.体外培养BMSC,携带增强型绿色荧光蛋白(EGFP)的腺病毒转染标记后备用.颈总动脉球囊损伤后,以107个/kg的细胞数经颈外动脉移植到损伤动脉局部,对照组注射等量的PBS液.移植后1周取材行免疫组织化学检测BMSC归巢.移植后2周免疫组织化学染色检测血管内膜血小板-内皮细胞黏附分子(CD31)、α-平滑肌肌动蛋白(SM α-actin)及增殖细胞核抗原(PCNA)的表达;移植后4周行颈总动脉造影检测血管狭窄率,HE染色检测损伤血管新生内膜面积、新生内膜面积/中膜面积的变化.结果 BMSC移植组在术后1周损伤血管的内膜有表达EGFP的BMSC归巢.术后2周BMSC移植组血管内膜有连续性CD31的表达,对照组为阴性;BMSC移植组PCNA的表达较对照组明显降低(23.43％±2.80％比50.49％±3.60％,P＜0.05),而BMSC移植组SM α-actin的表达较对照组明显增加(0.437±0.049比0.197 ±0.032,P＜0.01).术后4周HE结果显示:BMSC移植组血管新生内膜面积(0.103±0.022比0.214±0.024,P＜0.01)、新生内膜/中膜面积(0.771±0.096比1.646±0.223,P＜0.01)均较对照组减轻;颈动脉造影结果显示:BMSC移植组较对照组血管再狭窄率减轻(39.64％±2.30％比63.31％±2.82％,P＜0.05).结论 移植BMSC可促进颈动脉球囊损伤后早期再内皮化和血管平滑肌细胞表型转化,抑制血管新生内膜的增生,减轻了血管再狭窄.     

多沙唑嗪对血管狭窄和血清一氧化氮的影响

目的探讨多沙唑嗪对兔腹主动脉球囊损伤后血管狭窄的影响,及其与血清一氧化氮、血管内膜中膜平滑肌细胞增生的关系。方法23只新西兰兔随机分为正常对照组、球囊损伤组、多沙唑嗪组。正常对照组不予任何方式处理。另两组行腹主动脉球囊损伤术,同时多沙唑嗪组应用多沙唑嗪控释片4mg/d,观察各组血清一氧化氮以及血管损伤处血管狭窄、血管内膜中膜增殖细胞核抗原(PCNA)的变化。结果应用多沙唑嗪4周后多沙唑嗪组血清一氧化氮含量增高,血管损伤处血管内膜、外膜增生减轻,新生内膜面积减少,管腔面积增加,内弹力层和外弹力层包围面积增加,血管内膜中膜PCNA阳性平均灰度降低。结论多沙唑嗪可以抑制球囊损伤后兔腹主动脉血管的狭窄,抑制血管内膜中膜平滑肌细胞增殖,增加血清一氧化氮含量。     

依维莫司对大鼠颈总动脉球囊损伤后内膜增生的影响

目的:探讨依维莫司对大鼠颈总动脉球囊损伤模型增生内膜的影响及其可能作用机制.方法:健康雄性SD大鼠36只,随机分为假损伤组(对照组)、颈总动脉球囊损伤组(损伤组)和颈总动脉球囊损伤+口服依维莫司组(依维莫司组),每组12只.依维莫司组于颈总动脉球囊损伤前1天,用依维莫司负荷剂量1.5 mg/kg灌胃,随后给予其剂量0.75 mg·kg-1·d-1灌胃直至第28天,对照组与损伤组给予等量0.9%氯化钠溶液灌胃.各组均于术后第28天取颈总动脉损伤段,观测颈动脉形态学变化,以免疫组化法测定损伤血管内膜真核翻译起始因子4E(eIF-4E)及增殖细胞核抗原(PCNA)的表达情况.结果:对照组血管内膜无增生,eIF-4E、PCNA表达极少;与对照组比较,损伤组新生内膜形成并增生明显,eIF-4E、PCNA表达显著增强;依维莫司组较损伤组新生内膜增生减轻,eIF-4E及PCNA表达明显降低,差异有统计学意义(P＜0.05).结论:依维莫司可抑制大鼠颈总动脉球囊损伤模型新生内膜增殖.其作用机制可能与抑制eIF-4E及PCNA表达有关.     

重组人粒细胞集落刺激因子对兔颈动脉粥样硬化球囊损伤后再内皮化和内膜增生的影响

目的 利用干细胞动员剂重组人粒细胞集落刺激因子(rhG-CSF)动员骨髓问充质干细胞(MSCs),探讨其对兔颈动脉粥样硬化球囊损伤后再内皮化和内膜增生过程的影响.方法 制作颈动脉粥样硬化狭窄兔模型67只,分为rhG-CSF组(rhG-CSF+球囊损伤,n=35)和对照组(生理盐水+球囊损伤,n=32).以流式细胞仪检测外周血MSCs数量,苏木精咿红法染色观察损伤动脉形态,免疫组织化学检测增殖细胞核抗原(PCNA).结果 (1)rhG-CSF应用前,两组之间的外周血MSCs细胞数量差异无统计学意义.应用rhG-CSF后24 h外周血MSCs数量显著增加(P＜0.01),第7天达到高峰,14 d时仍明显增高;而对照组各个时间点MSCs数量差别均无统计学意义.(2)形态学观察显示,球囊损伤后1周,对照组内皮细胞仍然大片缺失,仪见少数新生的内皮细胞,而rhG-CSF组内皮细胞散在覆盖,新生内皮排列不规则.14 d时,对照组内皮覆盖面较小,基底层片状裸露,而rhG-CSF组内皮呈小片状覆盖.28 d时rhG-CSF组内皮间连接建立,细胞排列呈现方向性.(3)免疫组织化学检测显示,球囊损伤后,动脉中膜近血管腔侧可见少量PCNA阳性细胞,而新生内膜PCNA 阳性细胞最多.rhG-CSF组于7、14、28 d时,PCNA阳性细胞率(细胞增殖指数)均显著低于对照组(均P＜0.01).结论 rhG-CSF能有效地促进骨髓释放MSCs,提高外周血MSCs数量,并促进损伤动脉再内皮化,抑制新生内膜增生,改善血管重塑.     

骨髓间充质干细胞移植对兔腹主动脉成形术后血管内膜的影响

目的探讨骨髓间充质干细胞(BMSC)移植对兔腹主动脉再狭窄和平滑肌细胞增殖的影响及机制。方法将60只新西兰大白兔随机分为对照组、损伤组、移植组,各20只。损伤组和移植组送入球囊扩张损伤腹主动脉,移植组以1×107/kg细胞数将荧光标记的BMSC注射到损伤血管局部。术后4周免疫组织化学染色腹主动脉平滑肌肌动蛋白(α-SM-actin)、增殖细胞核抗原(PCNA),计算PCNA增殖指数,血管形态计量分析。结果损伤组新生血管内膜层α-SM-actin表达明显强于对照组(P<0.05);与损伤组比较,移植组新生血管内膜α-SM-actin表达明显增强(P<0.05)。损伤组PCNA阳性细胞数较对照组明显增多(P<0.05);移植组PCNA阳性细胞数较损伤组明显减少(P<0.05)。损伤组腹主动脉内膜厚度和面积、中膜厚度和面积、血管狭窄程度等明显高于移植组和对照组(P<0.05);移植组上述指标与对照组比较,无统计学差异(P>0.05)。结论 BMSC血管局部移植可抑制兔腹主动脉血管平滑肌细胞的增殖,减轻动脉粥样硬化及狭窄程度。     

辛伐他汀和粒细胞集落刺激因子对血管内皮损伤的修复效应

目的探讨在大鼠颈动脉球囊损伤模型中,通过刺激骨髓,加强内皮祖细胞向周围血动员对损伤血管内皮修复和抑制新生内膜的效果。方法制备大鼠颈动脉球囊损伤模型。对照组(n=14)给予生理盐水灌胃,辛伐他汀组(n=12)及合并使用辛伐他汀与粒细胞集落刺激因子(G-CSF)组(n=12)给予辛伐他汀10mg/(kg.d)灌胃,辛伐他汀与G-CSF组加用G-CSF100μg/(kg.d)腹腔注射,给药均从术前1周至术后2周。测定损伤血管内皮修复率、新生内膜/中膜面积比(IA/MA)、增殖性细胞核抗原(PCNA)阳性细胞指数、外周血一氧化氮(NO)含量,流式细胞仪检测CD34 血管内皮生长因子受体2(VEGFR-2) 双荧光阳性细胞比例。结果成功建立大鼠颈动脉损伤模型。与对照组比较,辛伐他汀组内皮修复率增加12.3%,IA/MA减少18.4%、外周血NO含量增加33.9%(P均<0.05);PCNA阳性表达指数降低5.7%(P>0.05);辛伐他汀与G-CSF组上述指标分别为38.2%,50.3%,33.9%和37.2%(P均<0.05)。与对照组比较辛伐他汀可增加外周血CD34 VEGFR-2 双荧光阳性细胞比例87.6%,合用辛伐他汀与G-CSF则可增加达343.4%(P均<0.05)。结论在颈动脉球囊损伤模型,辛伐他汀可以促进损伤血管内皮修复达到抑制新生内膜增殖的效果,其机制可能涉及加强骨髓中内皮祖细胞向外周血的动员。在辛伐他汀基础上合用G-CSF刺激骨髓,可以使上述效应进一步加强。     

Prostacyclin synthase gene transfer inhibits neointimal formation in rat balloon-injured arteries without bleeding complications.

OBJECTIVE: This study was designed to compare the effects of prostacyclin synthase (PCS) gene transfer with those of a systemic infusion of beraprost sodium (BPS), a prostacyclin analogue, on vascular smooth muscle cell (VSMC) proliferation and neointimal formation after arterial injury. METHODS: PCS gene (3 or 30 micrograms) was transfected into rat balloon-injured carotid arteries by a non-viral lipotransfection method. BPS (100 or 300 micrograms/kg/day) was subcutaneously infused with osmotic pumps after the injury. LacZ gene (30 micrograms) was used as a control. VSMC proliferation was estimated by the bromodeoxyuridine (BrdU) index (BrdU-positive nuclei/total nuclei) at day 7. Neointimal formation was evaluated at day 14. Each treatment group had six rats. RESULTS: PCS gene transfer prevented the increase in intimal/medial area ratio (3 micrograms: 46.6%, 30 micrograms: 61.1% reduction; P < 0.05, P < 0.01, respectively), as did BPS 300 micrograms/kg/day (49.8% reduction; P < 0.05). BPS 100 micrograms/kg/day, however, had no effects on the ratio. PCS gene transfer and BPS 300 micrograms/kg/day significantly suppressed the BrdU index. BPS 300 micrograms/kg/day group had more frequent hematoma and longer bleeding time. There were no significant differences in blood pressure, heart rate, or urinary volume among all groups. CONCLUSION: Both PCS gene transfer and BPS 300 micrograms/kg/day reduced neointimal formation after arterial injury by inhibiting VSMC proliferation. PCS gene transfer may be a safer therapeutic modality against neointimal formation than a systemic infusion of BPS because the former method resulted in fewer bleeding complications.     

DIM对兔血管损伤后平滑肌细胞C-myc表达的影响

目的探讨DIM对血管损伤后血管平滑肌细胞增殖的影响及其可能机制。方法制备兔血管再狭窄模型,21只兔随机分为假手术组、模型组和DIM组,观察各组颈总动脉形态学变化,采用免疫组织化学技术观察血管内膜C-myc的表达。结果假手术组动脉各层结构正常;模型组动脉内膜层出现泡沫细胞,平滑肌细胞增殖,血管内膜明显增厚,C-myc表达明显增加;DIM组血管平滑肌细胞增殖程度降低;与假手术组比较,模型组C-myc表达显著增强(P<0.05),而DIM明显降低C-myc的表达(P<0.01)。结论 DIM通过下调C-myc基因的表达而抑制血管内膜增生,有利于血管再狭窄的防治。     

Troglitazone improves blood flow by inhibiting neointimal formation after balloon injury in Otsuka Long-Evans Tokushima fatty rats

Troglitazone (TGZ) is an antidiabetic agent of the thiazolidinedione (TZD) class that potentiates insulin action. In addition to its effects on insulin action, TGZ has an antiproliferative effect on vascular smooth muscle cells (VSMCs), of which proliferation is a prominent feature of retenosis after balloon injury, as well as atherosclerosis. Therefore, we investigated the effects of TGZ on intimal formation and blood flow after balloon injury in insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rats to see whether the decrease in insulin resistance could minimize VSMC proliferation and could maintain blood flow. OLETF rats, an animal model of type 2 diabetes, develop spontaneous hyperglycemia after the age of 24 weeks. Balloon injury was applied to the left common carotid arteries of the rats with a 2F Fogarty catheter. Two weeks after the balloon injury, blood flow velocity was measured with Doppler ultrasonography, and histomorphometric analyses of the common carotid arteries were performed. The neointimal formation caused by VSMC proliferation was inhibited by TGZ treatment by as much as 80% (0.197 +/- 0.013 mm(2) v 0.157 +/- 0.011 mm(2), P <.05). The ratio of neointimal to medial area also decreased by 22% with TGZ treatment (1.651 +/- 0.148 v 1.292 +/- 0.083, P <.05). These effects of TGZ in OLETF rats were accompanied by alterations in plasma insulin, triglyceride, and total cholesterol levels. To look into the relationship between VSMC proliferation and hyperinsulinemia, we used a [(3)H]-thymidine incorporation assay to investigate the effects of TGZ on VSMC proliferation. Insulin (at a concentration of 17.3 nmol/L) significantly stimulated DNA synthesis (236.6% +/- 7.4%, P <.001), and TGZ significantly inhibited the insulin-induced DNA synthesis in VSMCs (106.43% +/- 4.23%, P <.001) in a dose-dependent manner. In balloon-injured arteries of the untreated group, systolic blood flow velocity decreased by 61% compared with uninjured arteries (P <.05). However, there was no significant difference in systolic blood flow velocity between injured and uninjured arteries in the treated group (0.906 +/- 0.043 v 0.991 +/- 0.066 meters per second [m/s], P = not significant [NS]). The systolic blood flow of injured arteries was improved by 143% in the treated group (P <.01). These data suggest that TGZ is a potent inhibitor of VSMC proliferation both in vivo and in vitro through a direct effect on VSMCs, and that TZDs might be very useful in the treatment and prevention of restenosis after balloon injury.     

Resveratrol inhibits neointimal formation after arterial injury through an endothelial nitric oxide synthase-dependent mechanism

Revascularization procedures used for treatment of atherosclerosis often result in restenosis. Resveratrol (RSV), an antioxidant with cardiovascular benefits, decreases neointimal formation after arterial injury by a mechanism that is still not fully clarified. Our main objective was to address the role of nitric oxide synthases (NOSes) and more specifically the endothelial-NOS (eNOS) isoform as a mediator of this effect. RSV (4 mg/kg/day, s.c.) alone or in combination with the NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME) (2 mg/kg/day, s.c.) was given to Sprague-Dawley rats beginning at 3 days before arterial (carotid or aortic) injury. RSV reduced neointimal formation by 50% (P<0.01), decreased intimal cell proliferation by 37% (P<0.01) and reduced inflammatory markers such as PECAM and MMP-9 mRNA. These effects of RSV were all abolished by coadministration of l-NAME. Oral RSV (beginning at 5 days before arterial injury) reduced neointimal thickness after femoral wire injury in mice, however this effect was not observed in eNOS knockout mice. This is the first report of RSV decreasing neointimal cell proliferation and neointimal growth through an eNOS-dependent mechanism.     

Anti-human von willebrand factor monoclonal antibody AJvW-2 prevents thrombus deposition and neointima formation after balloon injury in guinea pigs

Immediately after angioplasty, platelet adhesion to the injured arterial wall and subsequent release of various mitogens may contribute to neointima formation. The purpose of this study was to evaluate the inhibitory effect of AJvW-2, a monoclonal antibody against human von Willebrand factor (vWF), on neointima formation in a guinea pig model. The carotid artery was injured with a balloon catheter, and AJvW-2 was administered by a single bolus injection. AJvW-2 dose-dependently prevented neointima formation 14 days after injury. Significant inhibition was observed at 1.8 mg/kg, at which dose significant inhibition of platelet aggregation was achieved for 2 days. By elastic-Masson staining, organized thrombi were observed in the neointimal lesion on day 14. The thrombus area was significantly correlated with neointimal thickness. Furthermore, thrombus deposition, immunostained for vWF and fibrin(ogen), was observed on the media immediately after balloon injury. AJvW-2 significantly reduced the deposition of both adhesive proteins and reduced the incidence of organized thrombus formation, which might affect subsequent neointima formation. However, the proliferation of cultured smooth muscle cells was not affected by AJvW-2. These results suggest that AJvW-2 prevents neointima formation by inhibition of initial platelet-mediated thrombus formation rather than by direct inhibition of smooth muscle cell proliferation.     

Effects of hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin on smooth muscle cell proliferation in vitro and neointimal formation in vivo after vascular injury

OBJECTIVES: We sought to evaluate the effects of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on vascular smooth muscle cell (VSMC) proliferation in vitro and neointimal formation in vivo after vascular injury. BACKGROUND: Neointimal hyperplasia after vascular injury is responsible for restenosis after arterial stenting, whereas arterial remodeling and neointimal formation are the causes of restenosis after percutaneous transluminal coronary angioplasty. METHODS: We assessed the effect of simvastatin on in vitro VSMC proliferation. To study the effects of simvastatin in vivo, balloon injury and stent deployment were performed in the common carotid artery of rats. Neointimal area was measured two weeks later in the balloon injury model and three weeks after stent deployment. RESULTS: Simvastatin markedly inhibits VSMC proliferation in vitro. In vivo, simvastatin reduced, in a dose-dependent manner, the neointimal area and the neointima-media ratio after balloon injury from 0.266 +/- 0.015 mm2 to 0.080 +/- 0.026 mm2 and from 1.271 +/- 0.074 to 0.436 +/- 0.158 (p < 0.001 vs. control rats) at the highest dose. Simvastatin also significantly reduced the neointimal formation and the neointima-media ratio after stenting from 0.508 +/- 0.035 mm2 to 0.362 +/- 0.047 mm2 (p < 0.05 vs. control rats) and from 2.000 +/- 0.136 to 1.374 +/- 0.180 (p < 0.05 vs. control rats). The vessel thrombosis rate after stent deployment was 30% in the control group and 11.1% in the treated group (p = NS). Moreover, the systemic administration of simvastatin did not affect hepatic and renal functions, blood pressure or heart rate. CONCLUSIONS: Simvastatin potently inhibits VSMC proliferation in vitro and reduces neointimal formation in a rat model of vascular injury.     

Different response to balloon angioplasty of carotid and coronary arteries: effects on acute platelet deposition and intimal thickening

PTCA is a well-established intervention to reduce the severity of atherosclerotic coronary stenosis. Its primary success rate is seriously handicapped by the high incidence of late restenosis. Given the clinical and social importance of this proliferative process, new strategies are needed to prevent or reduce restenosis. Several animal models as well as different arteries have been used to study neointimal proliferation after arterial injury. A number of agents have shown to reduce neointimal proliferation after arterial injury in the carotids and iliac arteries of rodent models. Unfortunately, these results have not been replicated in humans. We have compared the acute and late response to vascular injury of the carotid and coronary arteries in the pig. Arterial injury was induced by performing balloon angioplasty of the carotid (elastic) and coronary (muscular) arteries in swine. Acute platelet-thrombus formation was evaluated by quantitation of Indium-labeled platelets deposited on the injured segments 1 h after procedure. Measurement of intimal area was performed by morphometry of the most stenotic cross-section at 28 days after balloon angioplasty. Platelet deposition after mild and severe injury in carotids (4±1 and 56±13×10⁶ platelets/cm², respectively) and coronaries (15±5 and 141±20×10⁶ platelets/cm², respectively) are significantly greater in deep, than in mild injury (P<0.005), and significantly greater in coronary than in carotid arteries after deep injury (P<0.05). Likewise, late neointima formation was significantly greater (P<0.05) after mild and severe injury in coronary (17±0.5 and 56 ±2%, respectively) than in carotid arteries (5±0.5 and 12±1%, respectively). Acute platelet-thrombus formation and late neointimal thickening are modulated by the degree of injury induced during the interventions; and after disruption of the internal elastic lamina, coronary arteries always had significantly more acute thrombus and neointimal thickening. This study emphasizes the importance of the animal species, the type of injury and the artery chosen for studies on restenosis post interventions.     

Porphyromonas gingivalis promotes neointimal formation after arterial injury through toll-like receptor 2 signaling

We previously demonstrated that Porphyromonas gingivalis infection induces neointimal hyperplasia with an increase in monocyte chemoattractant protein (MCP)-1 after arterial injury in wild-type mice. Toll-like receptor (TLR) 2 is a key receptor for the virulence factors of P. gingivalis. The aim of this study was to assess whether TLR2 plays a role in periodontopathic bacteria-induced neointimal formation after an arterial injury. Wild-type and TLR2-deficient mice were used in this study. The femoral arteries were injured, and P. gingivalis or vehicle was injected subcutaneously once per week. Fourteen days after arterial injury, the murine femoral arteries were obtained for histopathologic and immunohistochemical analyses. The immunoglobulin-G levels of the P. gingivalis-infected groups were significantly increased in comparison with the level in the corresponding noninfected groups in both wild-type and TLR2-deficient mice. TLR2 deficiency negated the P. gingivalis-induced neointimal formation in comparison with the wild-type mice, and reduced the number of positive monocyte chemoattractant protein-1 cells in the neointimal area. These findings demonstrate that P. gingivalis infection can promote neointimal formation after an arterial injury through TLR2 signaling.     

黄连素对血管平滑肌细胞增殖、大鼠颈动脉球囊损伤模型及PTEN基因表达的影响

目的:探讨黄连素对血管平滑肌细胞(VSMC)增殖、大鼠颈动脉球囊损伤后动脉新生内膜形成及损伤后再狭窄的影响,及其影响是否通过改变PTEN(第10q23染色体的抑癌基因)的表达来实现。方法:MTT法检测黄连素对主动脉VSMC增殖的影响,实时定量RT-PCR及Western blot法测定黄连素对VSMC PTEN在转录及蛋白水平表达的影响。建立颈动脉球囊损伤模型,观察黄连素对新生内膜形成及再狭窄的影响及血管组织表达PTEN的变化。结果:黄连素抑制大鼠主动脉VSMC的增殖,改善损伤血管新生内膜形成及再狭窄;上调PTEN表达,且与浓度呈正相关,200μmol/L黄连素干预VSMC效果最佳;球囊损伤模型再狭窄的预防经过术前、术后各2周的黄连素处理,较单纯术后黄连素处理效果更佳。结论:黄连素可能通过上调PTEN表达来抑制VSMC增殖与球囊损伤模型内膜的增生及损伤后再狭窄。     

Evidence for 12-lipoxygenase induction in the vessel wall following balloon injury.

OBJECTIVE: Vascular smooth muscle cell (VSMC) migration and proliferation are key events in the development of atherosclerosis and restenosis following angioplasty. These events are mediated by several growth factors and cytokines whose cellular effects include activation of phospholipases and arachidonic acid metabolism via the lipoxygenase (LO) pathway. Since 12-LO products have potent growth and chemotactic effects, we have examined if 12-LO is upregulated in the neointima of injured rat carotid arteries and also if LO inhibition could attenuate neointimal thickening. METHODS: The left common carotid arteries of male Sprague Dawley rats were injured using a 1.8 F PTCA balloon catheter. Four-fourteen days after injury, injured and uninjured tissue samples were processed for histology, and immunohistochemistry or polymerase chain reaction (PCR) to examine 12-LO expression. RESULTS: Twelve days after injury, immunohistochemical staining with a 12-LO antibody revealed intense staining in injured left carotid arteries, mainly in neointimal VSMCs and inflammatory cells, but not in the uninjured right arteries. There was also a marked upregulation of 12-LO mRNA (over five-fold by competitive PCR) in the injured arteries. Treatment of the arteries with a LO inhibitor, phenidone, soon after injury resulted in significant inhibition of neointimal thickening. In contrast, a cyclooxygenase inhibitor, ibuprofen, had no effect. CONCLUSIONS: These results indicate for the first time that balloon injury results in marked induction of 12-LO mRNA and protein expression in the vessel wall. Furthermore, LO pathway activation may mediate, at least in part, the development of the lesion or plaque instability, suggesting a novel target for therapeutic intervention to block these pathological events.