Irbesartanf对大鼠髂动脉球囊内皮剥脱后血管壁增殖的影响

目的 观察Irbesartan对血管损伤后内膜增殖的作用。方法 24只髂总动脉球囊内膜剥脱的Wistar大鼠随机等分为三组，分别于术前1天至术后14天食管内喂饲Irbesartan 30mg/kg·d或蒸馏水。术后14天对损伤血管进行形态学检查。结果 Irbesartan显抑制损伤血管壁中细胞计数增加和内膜增厚以及血管平滑肌细胞增殖，并且有量效关系。对新生内膜中细胞密度影响不大。结论 Irbesartan能够抑制大鼠髂总动脉球囊损伤后内膜增殖，Irbesartan可能是防治血管成形术后再狭窄的有效药物。     

血管内照射防止受损动脉狭窄形成的实验研究

目的 观察血管内照射防止受损受损动脉狭窄形成的有效性及相关性。方法 对小型猪髂动脉造影及血管内超声（IVUS）检查后行球囊扩张成形术。实验组通置源管将高剂量铱-192（^192Ir）后装源受损髂动脉分别施予不同剂量的血管内放射治疗。损伤对照组仅对受损髂动脉置入假源。术后28天处死动物即取受损髂动脉分析形态学及组织学变化。结果 对照组动脉内膜损伤处发生内弹力板断裂、内膜明显增殖及管腔狭窄。实验组新生内膜面积明显减少、血管腔面积及外弹力（EEM）包绕面积增加。结论 球囊扩张成形术后血管内高剂量^192Ir后装放射治疗,可防止术后新生内膜形成和血管重构,从而防止受损动脉狭窄形成。     

中药黄芪对球囊损伤大鼠颈总动脉后增殖细胞核抗原及细胞周期蛋白依赖性激酶表达的影响

目的:观察黄芪对球囊损伤大鼠颈总动脉内皮后对其细胞核增殖抗原(PCNA)及细胞周期蛋白依赖性激酶(cdks,cdk2,cdk4)表达的影响,探讨其可能机制。方法:随机将36只雄性SD大鼠分为对照组、手术组及黄芪组,球囊损伤大鼠颈总动脉前1天始给对照组和手术组0.8ml/100g/d生理盐水灌胃,黄芪组给予相同剂量的中药灌胃,连续至第5天和28天两个时间点处死大鼠,取其损伤的颈总动脉,应用组织学检查术后5天和28天的内膜增生情况和免疫组织化学方法检测5天时PCNA、CDK2、CDK4蛋白的表达。结果:球囊损伤颈总动脉术后5天时,血管内膜及内膜面积轻度增生,无统计学意义;28天时,手术组内膜增生明显,用中药黄芪后增生减少,与手术组比较差异有显著性(P<0.05),用黄芪后内膜增生面积减少,与手术组比较差异有显著性(P<0.05)。用免疫组织化学方法测术后5天各组PCNA、CDK2、CDK4蛋白阳性细胞的表达,手术组表达最强,用药后各组表达量均显著减少(P<0.01)。结论:中药黄芪对球囊损伤后动脉血管内膜增生有抑制作用,其机制可能与下调细胞核增殖抗原及细胞周期蛋白依赖激酶的表达,从而抑制血管内膜平滑肌细胞的增殖有关。     

离体和在体机械损伤致血管平滑肌增殖模型的建立

目的建立离体和在体机械损伤致血管平滑肌增殖模型。方法原代培养大鼠胸主动脉血管平滑肌细胞(VSMCs),体外建立机械划伤致VSMCs增殖模型,采用5-溴脱氧尿嘧啶(5-BrUd)掺入法,流式细胞术检测细胞增殖情况;整体动物上,采用新西兰兔左侧颈总动脉球囊损伤,术后7d取颈总动脉段,常规病理切片,HE染色,观测血管内膜厚度、内膜面积、内膜厚度/中膜厚度、内膜面积/中膜面积。结果机械划痕损伤12 h后划伤处两侧的细胞开始有部分增殖和迁移,24 h后细胞增殖较为明显。流式细胞术检测机械损伤后细胞增殖增多(P<0.05)。整体动物上,与假手术组比较,模型组术后7 d血管内膜厚度、内膜面积、内膜厚度/中膜厚度、内膜面积/中膜面积显著增加(P<0.01)。结论机械损伤可以导致离体和在体血管平滑肌细胞增殖。     

蝙蝠葛碱对大鼠血管内皮损伤后平滑肌细胞增殖的抑制作用

目的研究蝙蝠葛碱(Dau)对球囊损伤后血管平滑肌细胞(VSMC)增殖的抑制作用及其对细胞周期调控因子p27蛋白表达的影响。方法将25只♂SD大鼠随机均分为假手术组、单纯损伤组和Dau低、中、高剂量组,后4组行球囊内皮剥脱术,Dau组于术前3d开始,igDau25、50、100mg·kg-1·d-1,假手术组和单纯损伤组同期ig等量生理盐水。术后第14天处死所有大鼠,取胸主动脉进行HE染色,光镜下观察内膜损伤后形态学的变化,并进行图像分析。采用免疫组织化学技术检测球囊内皮损伤后血管平滑肌细胞p27蛋白表达的变化。结果球囊损伤后血管壁增生,Dau可剂量依赖性地减少新生内膜面积,增加管腔面积,降低球囊损伤后内膜及中膜厚度(P<0.05),抑制平滑肌细胞的增殖,促进p27蛋白的表达。结论p27参与了球囊损伤内皮后血管平滑肌细胞增殖的调节。Dau对损伤内皮所致平滑肌的增殖具有抑制作用,可防止血管再狭窄,其机理可能是通过调节p27的表达实现的。     

碘化N-正丁基氟哌啶醇抑制兔颈总动脉球囊损伤后血管内膜和平滑肌细胞增殖的作用研究

目的:探讨碘化N-正丁基氟哌啶醇(F2)对兔颈总动脉球囊损伤后内膜及平滑肌细胞增殖的影响。方法:30只新西兰兔随机分为假手术组、模型组、F2高剂量给药组(2mg/kg)、F2中剂量给药组(1mg/kg)、F2低剂量给药组(0.5mg/kg)。模型组及F2各给药组行左侧颈总动脉球囊损伤,各组分别于术后7d取颈总动脉段,常规病理切片,HE染色,免疫组化法测定α-actin、增殖细胞核抗原(PCNA)的表达水平。结果:与假手术组比较,模型组术后7d血管内膜厚度、内膜面积、内膜厚度/中膜厚度、内膜面积/中膜面积、血管壁细胞PCNA表达显著增加(P<0.01),F2剂量依赖地降低上述指标。与假手术组比较,模型组血管壁α-actin阳性染色减少,F2各给药组可增加血管壁平滑肌细胞中α-actin阳性染色率。结论:F2能抑制兔颈总动脉机械损伤后血管内膜和平滑肌细胞的增殖。     

缬沙坦对球囊损伤后血管平滑肌细胞增生的影响

目的 探讨缬沙坦因子防治人类血管成形术后再狭窄的可行性方法观察新的非肽类血管紧张素Ⅱ的Ⅰ型(AT_1)受体拮抗剂,缬沙坦(Valsartan),对血管平滑肌细胞(VSMC)增生的影响。对大鼠髂动脉球囊内皮剥脱术后过度增生模型采用~3H-TdR和~3H-Leu掺入,免疫组化染色检测VSMC中增殖细胞核抗原(PCNA)的表达及图象分析血管壁形态学变化。结果 缬沙坦显著减少~3H-TdR和~3H-Leu的掺入量,减少新生内膜面积和PCNA阳性细胞数。结论 缬沙坦能抑制大鼠动脉的球褒内皮损伤后的VSMC增生,可能它是防治血管成形术再狭窄的有效药物。     

血管成形术后再狭窄与平滑肌细胞转化和迁移及转化生长因子α表达上调有关

目的为探讨血管成形术后再狭窄形成与平滑肌细胞(Smooth muscle cells,即SMCs)的迁移和表型转化,以及转化生长因子α(Transforming growth factor-α,即TGFα)在内膜增生过程中的表达变化的关系。方法取40只Sprague-Dawle大鼠行右颈总动脉球囊内膜剥脱术建立再狭窄动物模型,于第1,3,9,28天和2月取实验动脉段和对侧正常动脉段行光镜观察及计算机图像分析,同时在透射电镜下观察SMCs亚微结构变化。并以放免测定内膜增生时损伤血管组织中TGFα表达的变化。结果图像分析显示在球囊损伤第3天即见损伤血管中膜出现明显增厚,而后恢复正常厚度。与此同时球囊损伤第3天内膜明显增厚,而在第9～28天逐渐达到高峰;在透射电镜下观察可见:术后第3天损伤血管增生内膜中近腔面的SMCs就已主要表现为合成表型,在28d和2个月时大部分SMCs又恢复收缩表型的形态特征。而通过放免测定发现球囊损伤后第3天对血管组织TGFα表达明显增加,与对侧正常颈总动脉标本中的TGFα含量有统计学意义的差异。结论故认为大鼠再狭窄模型的内膜增生过程具有明显的时相特征,SMCs从中膜向内膜的迁移,而SMCs的表型转化在这过程中显示出明显的双向转化特点,而TGFα在损伤血管的表达明显增加,可能参与了内膜过度增生过程的SMCs的表型转化和迁移的机制。     

曲匹地尔及阿斯匹林对球囊血管成形术后血管增生及重构的影响

目的从血管病理角度观察血小板源生长因子（ＰＤＧＦ）抑制剂曲匹地尔（ｔｒａｐｉｄｉｌ）及血小板抑制剂阿斯匹林（ａｓｐｉｒｉｎ）对血管球囊成形术后内膜增生及重构的影响，为临床用药提供实验依据。方法对实验兔行髂动脉球囊成形术，术前３ｄ分别用ｔｒａｐｉｄｉｌ（２５ｍｇ·ｄ－１）及ａｓｐｉｒｉｎ（２５ｍｇ·ｄ－１），至术后２８ｄ取病变血管段切片染色，用计算机图像分析血管内膜、中膜厚度和腔面积、平均动脉面积的变化。结果ｔｒａｐｉｄｉｌ使腔面积扩大，平均动脉面积（外弹力膜内横截面积ＥＥＬ）增加明显，而ａｓｐｉｒｉｎ腔面积较ｔｒａｐｉｄｉｌ减少但较对照扩大，ＥＥＬ较对照及ｔｒａｐｉｄｉｌ组比较均减少。结论ｔｒａ－ｐｉｄｉｌ和ａｓｐｉｒｉｎ均抑制血管增生反应（以中膜平滑肌细胞为主），对血管重构的影响ｔｒａｐｉｄｉｌ较ａｓｐｉｒｉｎ明显     

滇丹参对血管狭窄和金属基质蛋白酶的影响

目的 探讨滇丹参对高血脂兔腹主动脉球囊损伤后血管狭窄的影响，及其与基质金属蛋白酶、血管内膜中层平滑肌细胞增生的关系。方法 25只日本大耳兔随机分为正常对照组、球囊损伤组与滇丹参组。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，其中滇丹参组给予静脉注射滇丹参注射液（238mg·kg^-1·d^-1）2周，观察各组血管组织中基质金属蛋白酶表达情况的变化以及血管损伤处血管狭窄、血管内膜中层平滑肌细胞增生的情况。结果 应用滇丹参2周后滇丹参组血管组织中基质金属蛋白酶表达减少，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。结论 滇丹参可以抑制血管组织中基质金属蛋白酶的表达，抑制血管内膜中膜平滑肌细胞增殖，抑制球囊损伤后兔腹主动脉血管的狭窄。     

Total Ginsenosides suppress the neointimal hyperplasia of rat carotid artery induced by balloon injury

Ginsenosides, the active components found in Panax ginseng, have been reported to inhibit the cardiac hypertrophy in rats. This study aims to observe the potential effect of total ginsenosides (TG) on the hypertrophic vascular diseases. The model of vascular neointimal hyperplasia was established by rubbing the endothelia of the common carotid artery with a balloon in male Sprague Dawley rats. TG (15 mg/kg/day, 45 mg/kg/day), L-arginine (L-arg) 200 mg/kg/day, and NG-nitro-L-arginine-methyl ester (L-NAME) 100 mg/kg/day used with the same dose of L-arg or TG 45 mg/kg/day were given for 7 and 14 consecutive days after surgery. TG and L-arg administrations significantly ameliorated the histopathology of injured carotid artery, which was abolished or blunted by L-NAME, an NOS inhibitor; TG and L-arg could also remarkably reduce the expression of proliferating cell nuclear antigen (PCNA), a proliferation marker of vascular smooth muscle cells(VSMCs), in neointima of the injured artery wall. Further study indicated that balloon injury caused a decreased superoxide dismutase (SOD) activity and an elevated malondialdehyde (MDA) content in plasma, and reduced the cGMP level in the artery wall, which were reversed by TG. It was concluded that TG suppress the rat carotid artery neointimal hyperplasia induced by balloon injury, which may be involved in its anti-oxidative action and enhancing the inhibition effects of NO/cGMP on VSMC proliferation.     

Chimeric DNA-RNA hammerhead ribozyme targeting transforming growth factor-beta 1 mRNA inhibits neointima formation in rat carotid artery after balloon injury

We designed and synthesized a chimeric DNA-RNA hammerhead ribozyme targeting transforming growth factor (TGF)-beta 1 mRNA and found that this ribozyme effectively and specifically inhibited growth of vascular smooth muscle cells. We examined the effects of the chimeric DNA-RNA hammerhead ribozyme targeting TGF-beta 1 mRNA on neointima formation and investigated the underlying mechanism to develop a possible gene therapy for coronary artery restenosis after percutaneous transluminal coronary angioplasty. Expression of mRNAs encoding TGF-beta 1, p27kip1, and connective tissue growth factor (CTGF) in carotid artery increased after balloon injury. Fluorescein-isothiocyanate (FITC)-labeled ribozyme was taken up into the midlayer smooth muscle of the injured carotid artery. Both 2 and 5 mg of ribozyme reduced neointima formation by 65% compared to that of controls. Ribozyme markedly decreased expression of TGF-beta 1 mRNA and protein in injured vessel. Mismatch ribozyme had no effect on expression of TGF-beta 1 mRNA protein in injured vessel. Ribozyme markedly decreased expression of fibronectin, p27kip1, and CTGF mRNAs in injured vessel, whereas a mismatch ribozyme had no effect on these mRNAs. These findings indicate that the chimeric DNA-RNA hammerhead ribozyme targeting TGF-beta 1 mRNA inhibits neointima formation in rat carotid artery after balloon injury with suppression of TGF-beta 1 and inhibition of extracellular matrix and CTGF. In conclusion, the hammerhead ribozyme against TGF-beta 1 may have promise as a therapy for coronary artery restenosis after percutaneous transluminal coronary angioplasty.     

Morphologic and functional consequences of intimal hyperplasia in the rat carotid artery

The influence of neointima formation on functional characteristics was investigated in rat carotid artery preparations. The process of intimal hyperplasia development in the injured carotid arteries was followed in time both morphologically and morphometrically. Simultaneously with the loss of endothelial cells due to the balloon injury procedure, the vasodilator responses to methacholine were abolished. The sensitivity for the α₁-adrenoceptor agonist phenylephrine appeared to be increased only immediately after injury. The balloon injury method led to significant neointima formation in the rat left common carotid artery 14 days after the intervention. Eight weeks after balloon injury, the neointimal mass reached its maximum. Parallel to the development of intimal hyperplasia, the α₁-mediated vasoconstrictor responses to phenylephrine were significantly impaired. After 12 weeks of observation, reoccurrence of mature endothelial cells on the luminal surface of the neointima could be observed. Simultaneously, the vascular responses to phenylephrine and methacholine recovered. The vasoconstrictor responses to high potassium concentrations (100 mM) as well as the vasodilator effects of sodium nitroprusside appeared to be uninfluenced by balloon injury throughout the period of observation. From this study we conclude that both the receptor-mediated contractile responses to α₁-adrenoceptor stimulation and the endothelium-dependent vasodilator responses to methacholine become severely impaired as a consequence of balloon catheter injury followed by intimal hyperplasia. However, these pharmacological responses may fully recover upon a prolonged period of endothelial regeneration. Received: 3 July 1997 / Accepted: 24 October 1997     

Pharmacological analysis for mechanisms of GPI-80 release from tumour necrosis factor-alpha-stimulated human neutrophils

1. The aim of this study was to evaluate whether caffeic acid phenethyl ester (CAPE), an active component of propolis, was able to reduce neointimal formation in a model of endothelial injury of rat carotid artery (balloon angioplasty). Furthermore, we investigated the relationship between neointima formation and nuclear factor-kappaB (NF-kappaB) activation and we correlated NF-kappaB activation to the expression of inducible isoform of cyclo-oxygenase (COX-2) in injured carotids. 2. In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-kappaB/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from sham-operated rats. Furthermore, NF-kappaB activation was correlated to increased COX-2, but not beta-actin, protein expression. 3. Treatment of rats for 14 days with CAPE (3, 10, 30 mg x kg(-1)) caused a significant inhibition of all the parameters assayed, except beta-actin protein expression. 4. These results indicate that treatment with CAPE may lead to a reduction of neointima formation by inhibiting NF-kappaB activation and suggest that this agent may have therapeutic relevance for the prevention of human restenosis.     

Angiotensin II type 1 receptor antagonist, TCV-116, prevents neointima formation in injured arteries in the dog.

We investigated the effect of an angiotensin (Ang) II antagonist, (+/-)-1-(cyclohexyloxycarbonyloxy)-ethyl 2-ethoxy- 1- [[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]- 1H-benzimidazole-7-carboxylate (TCV-116), on neointima formation in dog artery injured by a balloon catheter. Dogs were orally treated with 10 mg/kg TCV-116 or placebo twice a day for 5 weeks. After treatment with these drugs for 1 week, the right carotid artery was injured by a balloon catheter. The left carotid artery was regarded as the control. In the group treated with placebo, neointima formation in the injured arteries was observed. The activities of angiotensin converting enzyme (ACE) and chymase in the injured carotid arteries were increased 2.56- and 3.26-fold compared with those in the non-injured arteries, respectively. The neointimal area in dogs treated with placebo and TCV-116 were 0.51 +/-0.07 and 0.21 +/-0.07 mm2, respectively, and this difference was significant. In conclusion, an Ang II antagonist, TCV-116, prevented neointima formation by blocking the action of Ang II generated by both ACE and chymase in the injured arteries.     

Effect of a synthetic matrix metalloproteinase inhibitor (ONO-4817) on neointima formation in hypercholesterolemic hamsters

Degradation of extracellular matrix (ECM) proteins plays an important role in the development of vascular remodeling. We investigated the alteration of matrix metalloproteinases (MMPs) on the development of neointima formation and the effect of a newly synthesized MMP inhibitor using hypercholesterolemic hamsters. Endothelial injury was achieved by a catheter in the hamster carotid artery. Two weeks after the injury, neointima was detected in all hamsters. Oral administration (twice a day) of ONO-4817 was started 2 hours before injury and continued for the next 2 weeks. The neointimal area, with appearance of maze-like structures, was markedly reduced by 52.4 +/- 8.4% by treatment with ONO-4817 at a dose of 20 mg/kg per day. The treatment by ONO-4817 (20 mg/kg per day) significantly reduced the indexes of histone H1 on day 1, 5, and 10 and the BrdU index of intimal smooth muscle cells on day 5 and 10, but not on day 1. Whereas DNA synthesis was not reduced by ONO-4817, in vitro SMC migration on the other hand was reduced dose dependently. According to the results of western-blotting analysis, the expressions of MMPs were increased 1 week after injury. Especially, MMP-12 was not detected in hamsters without cholesterol diet, but it was much increased after injury in hypercholesterolemic hamsters. Additionally, active form of MMP-12 increased in the injured artery of hypercholesterolemic hamsters. In conclusion, inhibition of MMPs results in the suppression of neointima following vascular injury via both prevention of SMC migration and SMC proliferation of late phase in hypercholesterolemic hamsters. MMP-12 plays an important role on vascular stenosis in hypercholesterolemia and ONO-4817 could be a useful compound for the therapy for this field.     

香叶醇对大鼠颈动脉球囊损伤后血管内膜增生的抑制作用

目的 研究香叶醇对球囊损伤大鼠颈动脉损伤后血管内膜新生的影响及可能的机制。 方法 20 只雄性成年 SD 大鼠, 随机均分为 4 组。（1）假手术组： 不予以球囊损伤。（2）对照组： 予以球囊损伤, 不予以药物干预。（3）低浓度组： 球囊损伤后每日口服香叶醇 50 mg/kg。（4）高浓度组： 球囊损伤后每日口服香叶醇 200 mg/kg。 制作球囊损伤模型, 2 周后留取球囊损伤段血管制作病理切片, 苏木精-伊红（HE）染色法测量内膜与中膜（I/M）比值, 免疫组化法检测增殖细胞核抗原（PCNA）的表达, 用积分光密度（IOD）值表示, 并测定组织中氧化应激标志物 8-羟基脱氧鸟苷（8-OHdG）和脂质氧化产物丙二醛（MDA）的水平。 结果 与假手术组比较, 对照组 I/M 比值、IOD 值、8-OHdG 及 MDA 水平均升高; 与对照组比较, 低浓度组 I/M 比值、IOD 值、8-OHdG 均降低, 但 MDA 水平与对照组差异无统计学意义。 高浓度组与对照组比较 I/M 比值、IOD 值、8-OHdG 及 MDA 水平均降低, 且较低浓度降低更明显（P < O.05）。结论 香叶醇抑制大鼠颈动脉球囊损伤后内膜增生, 其机制可能与下调 PCNA 蛋白表达, 抑制活性氧的产生有关。     

Effects of G-CSF on cardiac remodeling and arterial hyperplasia in rats

Although granulocyte colony-stimulating factor (G-CSF) has been shown to prevent cardiac remodeling after acute myocardial infarction, the mechanism and safety of G-CSF treatment acute myocardial infarction remain controversial. The purpose of the present study was to investigate in a rat model the mechanisms underlying the beneficial effect of G-CSF in acute myocardial infarction and to determine whether G-CSF treatment aggravates vascular remodeling of injured artery after acute myocardial infarction. Sprague-Dawley rats received transplanted bone marrow cells from green fluorescent protein (GFP) transgenic rats. Acute myocardial infarction was induced by ligation of the left coronary artery. After 24 h, the right carotid artery was injured with a balloon catheter. G-CSF (100 microg/kg/day) or saline was injected subcutaneously for 5 consecutive days after induction of acute myocardial infarction. G-CSF treatment significantly improved left ventricle function and reduced infarct size in rats with acute myocardial infarction. Expression of mRNA for the angiogenic cytokines was significantly higher in the infarction border area in the G-CSF group than in the control group. The surviving cardiomyocytes in infarction area were more in the G-CSF group. GFP-positive cells were gathered in the infarction border area in both groups; G-CSF did not increase cardiac homing of GFP-positive bone marrow cells in contrast to control group. Most GFP-positive cells were CD68-positive (macrophages). It was difficult to find bone marrow-derived cardiomyocytes in the infarcted area. G-CSF treatment inhibited neointima formation and increased reendothelialization of the injured artery. GFP-positive cells were identified most in the adventitia of the injured artery. A few cells in the neointima and reendothelialization were GFP positive. In conclusion, administration of G-CSF appears to be effective for treatment of left ventricular remodeling after acute myocardial infarction and does not aggravate vascular remodeling. The effect of G-CSF on cardiac and vascular remodeling may occur mainly through a direct action on the heart and arteries.     

Pathophysiological roles of chymase and effects of chymase inhibitor

Human chymase forms angiotenin (ANG) I to ANG II, whereas the roles of ANG II generated by chymase and the effects of chymase inhibitors have been unclear. On the other hand, rat chymase could not convert ANG I to ANG II. In isolated rat arteries, the ANG I-induced vascular contraction was completely suppressed by angiotensin-converting enzyme (ACE) inhibitor only. However, 30% of ANG I-induced vascular contraction in isolated human arteries was suppressed by an ACE inhibitor, but the remainder was blocked by chymostatin. In hamster hypertensive models, ANG II formation by ACE, but not by chymase, in vascular tissues plays an important role in maintaining hypertension. ANG II formation also induces vascular remodeling such as neointima formation. After balloon injury of vessels in dog, chymase and ACE activities were significantly increased in the injured vessels. In this model, an ANG II receptor antagonist was effective in preventing neointimal formation after balloon injury of vessels in dog, but an ACE inhibitor was ineffective. In dog grafted veins, the activities of chymase and ACEmin the grafted vein were significantly increased 15- and 2-fold, respectively, compared with those in the symmetrical veins. The intimal area of the grafted vein was reduced by a chymase inhibitor. Therefore, chymase-dependent ANG II formation plays an important role in the proliferative response, and chymase inhibitors may appear useful for preventing vascular proliferation.