西立伐他汀对血管内皮细胞一氧化氮合酶及细胞间黏附分子的作用

目的　观察西立伐他汀对内皮细胞一氧化氮合酶 (NOsythase ,eNOS)和细胞间黏附分子 1 (intercellularadhesionmolecule 1 ,ICAM 1 )基因的表达 ,NOS活力和黏附的THP 1细胞量的影响。方法　以氧化LDL抑制培养的ECV 3 0 4细胞表达eNOS ,加入不同浓度西立伐他汀后 ,用RT PCR法检测eNOSmRNA ,硝酸还原酶法测定培养基中NO量。以脂多糖 (LPS)及西立伐他汀加入ECV 3 0 4细胞后 ,用RT PCR法检测ICAM 1mRNA ,并测定黏附的THP 1细胞量。结果　随着西立伐他汀浓度增加 ,内皮细胞eNOSmRNA水平增加 ,0 0 1 ,0 1 ,1 0 μmol/L时分别增加 5 0 %,1 5 0 %,3 0 0 %,P均 <0 0 5。培养液中NO亦相应增加 ,0 0 1 ,0 1 ,1 0 μmol/L时分别增加 2 6 7%,92 3 %,2 3 0 %,P <0 0 5。西立伐他汀浓度为 0 1 ,1 0 μmol/L时 ,ICAM 1mRNA分别从 70 7± 1 0 4降至 5 6 2± 6 5 ,3 5 8± 4 2 ,P <0 0 5。黏附于ECV 3 0 4细胞的THP 1细胞在 1 0 μmol/L时被抑制 2 6 %,P <0 0 5。结论　西立伐他汀能诱导内皮细胞eNOS基因的表达及增加NOS活力 ;抑制内皮细胞表达ICAM 1mRNA及THP 1细胞黏附于内皮细胞     

辛伐他汀通过磷酸化作用增强内皮一氧化氮合酶活性

目的建立含人内皮一氧化氮合酶(eNOS)基因的人胎肾细胞株,研究他汀类药物对eNOS活性的影响。方法用脂质体转染的方法将含有eNOS基因的质粒pcDNA3.1-eNOS导入人胎肾细胞(293细胞),利用G418筛选二次,以免疫印迹法鉴定并筛选出稳定表达eNOS的阳性克隆。将辛伐他汀(10μmol/L)加入eNOS阳性细胞系培养2h后,收获细胞并用同位素二步色谱法检测eNOS的活性,同时用Western Blot蛋白检测eNOS、磷酸化的eNOS表达水平和细胞内信号分子Akt、AMPK水平以探讨辛伐他汀调节eNOS活性的机制。结果Western Blot显示经转染pcDNA3.1-eNOS并筛选后的后的293细胞20%的克隆能稳定有效表达eNOS蛋白;辛伐他汀处理2h后eNOS活性明显升高(P<0.05)。结论成功建立了具有G418抗性的禽pcDNA3.1-eNOS基因的人胎肾细胞株,并且证明辛伐他汀可通过调节eNOS的活性来调节NO的生成,这可能为心血管疾病的治疗提高一种新的思路。     

他汀类药物预处理时间对兔心肌缺血再灌注损伤的影响

目的 观察普伐他汀、阿伐他汀和氟伐他汀一次性预处理的时间对兔心肌缺血再灌注损伤的影响及其机制.方法 选择日本大耳白兔70只,分别为普伐他汀、阿伐他汀和氟伐他汀组,每组21只,药物各组又分三个小组,对照组7只.实验前5d、3d和2h通过灌胃一次性分别给予普伐他汀、阿伐他汀和氟伐他汀10 mg/kg,随后制作心肌梗死模型,术后测量心肌梗死面积并检测缺血区内皮型一氧化氮合酶（eNOS）活性.体外实验部分培养人脐静脉内皮细胞（HUVECs）,观察以上他汀类药物作用0 min、5 min、15 min、20 min和30 min后诱导HUVECs表达eNOS的变化,通过Westernblot检测信号分子p-Akt（磷酸化丝/苏氨酸蛋白激酶）的含量.结果 提前2h给药能显著减少各组心肌缺血再灌注后的心肌梗死面积,增加缺血区eNOS的含量.缺血前5d和3d给药对心肌损伤改善不显著.细胞实验发现,以上他汀类药物20 min内即能上调血管内皮细胞eNOS表达,同时p-Akt的含量增加.结论 短时间内一次性预处理应用他汀类药物能够减轻缺血再灌注损伤.其机制可能与他汀类药物上调p-Akt信号分子,在短时间内诱导血管内皮细胞eNOS表达有关.     

氟伐他汀对人脐静脉内皮细胞游离钙离子水平及内皮型一氧化氮合酶活性的影响

目的:观察氟伐他汀对人脐静脉内皮细胞(HUVECs)游离钙离子水平及内皮型一氧化氮合酶(eNOS)活性的影响及可能机制。方法:体外培养HUVECs,随机分为5组:空白对照组,氟伐他汀(10-8,10-7,10-6,10-5mol/L)组。采用硝酸还原酶法测定细胞上清液中NO含量,液体闪烁计数仪测定L-[3H]-精氨酸和L-[3H]-瓜氨酸的含量,用激光共聚焦扫描显像系统检测内皮细胞内游离钙离子浓度([Ca2 ]i)水平的变化。结果:与空白对照组比较,10-8,10-7,10-6,10-5mol/L氟伐他汀孵育细胞12h后可显著升高HUVECs细胞内eNOS活性,促进NO释放,同时伴有[Ca2 ]i升高,且呈浓度依赖性。另外,10-5mol/L氟伐他汀在0～12h时间段呈时间依赖性增高eNOS活性,作用12h使eNOS活性达到最高(P<0.01)。结论:氟伐他汀呈浓度依赖性升高HUVECseNOS活性和促进NO释放,该作用与其增加内皮细胞内[Ca2 ]i有关。     

辛伐他汀对高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1表达的影响

目的研究他汀类药物对自发性高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1(LOX1)表达的影响,以了解血凝素样氧化低密度脂蛋白受体1在高血压病血管中的表达及探讨他汀类药物在高血压病中预防动脉粥样硬化的可能作用。方法20只12周龄雄性自发性高血压大鼠随机分为SHR组(n=10)和辛伐他汀组(n=10),辛伐他汀组每只大鼠予以辛伐他汀5mg/kg·d灌胃,给药时间8周,同时取10只12周龄雄性京都种Wistar大鼠作为WKY组,利用免疫组织化学和逆转录聚合酶链反应检测各组动物主动脉LOX1的表达。结果与WKY组比较,SHR组LOX1表达显著增加(012±005vs086±011,P<005),与SHR组比较,辛伐他汀组经8周治疗后,LOX1表达显著降低(086±011vs054±013,P<005),SHR组及辛伐他汀组之间血压及血清总胆固醇、总甘油三酯、低密度脂蛋白胆固醇水平无明显差异(P>005)。结论高血压大鼠主动脉内皮层LOX1表达增加,辛伐他汀对高血压大鼠主动脉内皮层LOX1的表达具有抑制作用,此种作用可能是他汀类药物独立于降脂外抗动脉粥样硬化新的机制。     

辛伐他汀对大鼠实验性高原性肺动脉高压内皮一氧化氮系统的影响

目的:通过观察辛伐他汀对高原性肺动脉高压大鼠模型内皮一氧化氮(NO)系统的影响,探讨他汀类药物对高原性肺动脉高压的影响及机制。方法:健康雄性成年大鼠40只,分为4组:对照组(N组);模型组(H+P组);辛伐他汀低剂量干预组(H+L组);辛伐他汀高剂量干预组(H+H组)。模型组及干预组置于减压舱,模拟海拔5000m高原,23h/d,持续21d。模型组每日以药物等容积的羧甲基纤维素钠溶液灌胃,低剂量及高剂量干预组每日分别以辛伐他汀2mg·kg-1·d-1及20mg·kg-1·d-1灌胃,共21d。测定各组大鼠肺动脉压、右心室肥大指数。荧光定量PCR测定肺组织内皮一氧化氮合酶(eNOS)的mRNA,比色法测定肺组织eNOS活力及NO含量。结果:1肺动脉压、右心室肥大指数指标,H+P组均高于其余3组(P0.01);H+L组与H+H组差异无统计学差异(P0.05);24组肺组织eNOS的mRNA含量无统计学差异(P0.05)。3N组、H+L组、H+H组间肺组织eNOS活力、NO含量无统计学差异(P0.05),均高于H+P组(P0.01)。结论:辛伐他汀对高原性肺动脉高压有防治作用,其机制可能与辛伐他汀可增加eNOS活力,促进NO合成有关,10倍剂量差异未造成降低肺动脉高压及影响eNOS的差异,为临床应用相对小剂量辛伐他汀达到预期的防治效果提供了可行性。     

基础血脂水平对HMG—CoA还原酶抑制剂降脂作用的影响

目的　观察治疗前基础血脂水平对HMG CoA还原酶抑制剂降低血清总胆固醇 (TC)、低密度脂蛋白胆固醇(LDL C)以及血清甘油三酯 (TG)作用的影响。方法　分析1994～ 1999年期间进行的 3项多中心临床药物试验 :辛伐他汀试验 (16 6例 ,平均年龄 5 8 9岁± 9 2岁 ) ,洛伐他汀试验(146例 ,平均年龄 5 7 9岁± 8 7岁 ) ,阿伐他汀试验 (10 5例 ,平均年龄 5 7 8岁± 9 3岁 )。治疗前血清TC≥ 5 98mmol·L-1,血清TG≤ 4 5 2mmol·L-1。按治疗前基础血脂水平分组。分别口服辛伐他汀 10mg·d-1,疗程 8周 ;或洛伐他汀2 0mg·d-1,疗程 8周 ;或阿伐他汀 10mg·d-1,疗程 6周。结果　治疗前基础血清TC、LDL C以及TG水平越高 ,HMG CoA还原酶抑制剂降低相应血脂的作用越明显。辛伐他汀、洛伐他汀或阿伐他汀降低血清TC、LDL C以及TG的幅度分别与治疗前相应的基础血脂水平呈正相关。结论　HMG CoA还原酶抑制剂降低血脂的作用与治疗前相应的基础血脂水平有关     

辛伐他汀对高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1表达的影响

目的研究他汀类药物对自发性高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1 (LOX-1)表达的影响,以了解血凝素样氧化低密度脂蛋白受体1在高血压病血管中的表达及探讨他汀类药物在高血压病中预防动脉粥样硬化的可能作用.方法 20只12周龄雄性自发性高血压大鼠随机分为SHR组(n=10)和辛伐他汀组(n=10),辛伐他汀组每只大鼠予以辛伐他汀5 mg/kg*d灌胃,给药时间8周,同时取10只12周龄雄性京都种Wistar大鼠作为WKY组,利用免疫组织化学和逆转录聚合酶链反应检测各组动物主动脉LOX-1的表达.结果与WKY组比较,SHR组LOX-1表达显著增加(0.12±0.05 vs 0.86±0.11,P<0.05),与SHR组比较,辛伐他汀组经8周治疗后,LOX-1表达显著降低(0.86±0.11 vs 0.54±0.13,P<0.05),SHR组及辛伐他汀组之间血压及血清总胆固醇、总甘油三酯、低密度脂蛋白胆固醇水平无明显差异(P>0.05). 结论高血压大鼠主动脉内皮层LOX-1 表达增加,辛伐他汀对高血压大鼠主动脉内皮层LOX-1 的表达具有抑制作用,此种作用可能是他汀类药物独立于降脂外抗动脉粥样硬化新的机制.     

洛伐他汀对成骨细胞骨形态发生蛋白2表达及碱性磷酸酶活性的影响

目的　观察洛伐他汀对成骨细胞骨形态发生蛋白 2 (BMP 2 )表达及碱性磷酸酶 (ALP)活性的影响 ,初步探讨洛伐他汀刺激成骨细胞的作用机制。　方法　体外培养成年小鼠的成骨细胞 ,对照组不用洛伐他汀 ,实验组以不同浓度 (0 2、0 5、1 0 μmol L)的洛伐他汀作用 72h后行细胞BMP 2免疫细胞化学染色、ALP染色及细胞ALP比活性测定。　结果　洛伐他汀作用 72h后 ,细胞ALP染色增强 ,胞浆内BMP 2表达水平增高 ,并随洛伐他汀浓度的增加而增加 ;对照组的成骨细胞几乎无BMP 2的表达。对照组ALP比活性为 (70 5 5 6± 171 4 0 )U·g- 1 ·L- 1 ,实验组洛伐他汀不同浓度组分别为 (716 39± 2 94 6 1)U·g- 1 ·L- 1 、(84 9 70± 2 30 0 9)U·g- 1 ·L- 1 、(983 4 8± 2 0 8 35 )U·g- 1 ·L- 1 ,其中 1 0μmol L组与对照组细胞ALP活性的差异有显著性 (P <0 0 5 )。　 结论　洛伐他汀的成骨作用与其促进成骨细胞BMP 2的高表达、引起细胞自分泌或旁分泌BMP 2增多、细胞ALP活性增高有关。     

赛格列酮对HUVECs表达eNOS和NO生成的作用

目的探讨过氧化物酶体增殖因子活化受体γ(PPARγ)激动剂赛格列酮,对血管紧张素Ⅱ(AngⅡ)诱导的人脐静脉内皮细胞(HUVECs)表达一氧化氮合酶(eNOS)及其一氧化氮(NO)生成的影响。方法体外培养HUVECs,用1×10-6～10-4mol/L赛格列酮预处理HUVECs24h,再与10-7mol/LAngⅡ共同孵育12h;通过RT-PCR和WesternBlot分别检测eNOSmRNA和蛋白表达水平;通过Griees反应测定上清NO释放量。结果与无刺激组比较,10-7mol/LAngⅡ刺激HUVECs12h后明显抑制eNOSmRNA及蛋白表达,P<0.001;基础状态下,HUVECseNOSmRNA及其蛋白表达较强,10-7mol/LAngⅡ刺激12h后明显下调eNOSmRNA和蛋白表达(与对照组相比,P<0.001)。各浓度赛格列酮预处理24h明显减弱AngⅡ对HUVECseNOSmRNA的下调作用(与AngⅡ组相比,P<0.001)。同样赛格列酮也明显减弱AngⅡ对HUVECseNOS蛋白表达的下调作用(与AngⅡ组相比,0.1、1μmol/L时P<0.01,10、100μmol/L时P<0.001,但0.1、1、10μmol/L赛格列酮组间比较P>0.05)。与无刺激组比较10-7mol/LAngⅡ明显减少NO的释放,P<0.05;与AngⅡ组比较,赛格列酮干预24h后呈浓度趋势增加NO的释放,P<0.001。结论赛格列酮呈浓度效应上调HUVECs表达eNOS,并呈浓度趋势增加内皮NO的释放。     

Short-term withdrawal of simvastatin induces endothelial dysfunction in patients with coronary artery disease: a dose-response effect dependent on endothelial nitric oxide synthase

BACKGROUND: Patients with coronary artery disease (CAD) have impaired endothelial function. Simvastatin therapy has been demonstrated to significantly improve endothelial function in these patients. Although withdrawal of statins is a frequent problem in clinical practice, the effects after discontinuation of statins treatment on endothelial function in patients with CAD are largely unknown. OBJECTIVE: This study investigated the effects after withdrawal of simvastatin on brachial artery endothelial function in patients with CAD and the underlying mechanisms. METHODS: We recruited 30 patients with established CAD. They were treated with 20 mg simvastatin for 4 weeks. Endothelial dependent flow-mediated vasodilation (FMD) was assessed in the brachial artery using high-resolution ultrasound at baseline, 4 weeks during simvastatin treatment, and 1 week after termination of therapy. 20 healthy subjects were also studied as a control group. Furthermore, we investigated underlying mechanisms on human umbilical vein endothelial cells (HUVECs) confluent monolayers at passages 2-3. HUVECs were exposed to simvastatin. After 24 h cells were repeatedly washed to remove the drugs, and the conditioned mediums were collected at the indicated time points. The nitric oxide (NO) production and levels of eNOS mRNA after 24 h of withdrawal of statins were examined. RESULTS: (1) Abrupt discontinuation of simvastatin treatment leads to a rebound of serum total cholesterol (21.3%) and LDL cholesterol (18.2%) in patients within 1 week, but they were still lower than the baseline values (P<0.05 for each parameter). (2) A significant decreased of FMD (-59.3%) was observed in patients after discontinuation of simvastatin in 1 week, and furthermore, the FMD was even lower than the baseline levels (4.6% vs. 5.6%, P<0.05). The reduction of FMD was not correlated with the change of LDL cholesterol (r=-0.343, P=0.081). In contrast to the unchanged LDL cholesterol level, abrupt discontinuation of therapy caused a rapid and significant decrease in FMD from 10.6% to 5.2% in healthy subjects at day 1, but it returned to baseline levels within 1 week. (3) In HUVECs, a maximum decrease of nitrite levels (-80%) was observed at 6 h after stopping simvastatin treatment, which was below the control levels. 24 h after stopping 10(-5) mmol/L and 10(-6) mmol/L simvastatin treatment, eNOS mRNA expression decreased to -71% and -42% (P<0.05), respectively. CONCLUSIONS: Abrupt withdrawal of simvastatin treatment not only acutely and completely abrogates its beneficial effects on endothelial function in patients with CAD, but also induced further vascular injury compared with pretreatment status, independent of cholesterol levels. The underlying mechanism of these negative effects may be related to the suppression of endothelial NO production, which are dose-dependent.     

Asymmetric dimethylarginine determines the improvement of endothelium-dependent vasodilation by simvastatin: Effect of combination with oral L-arginine.

OBJECTIVES: We hypothesized that the level of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS), might determine the endothelial effects of statins. BACKGROUND: Endothelial NO synthase is up-regulated by statins. However, statins failed to improve endothelial function in some studies. Asymmetric dimethylarginine inhibits eNOS by a mechanism that is reversible by L-arginine. METHODS: Ninety-eight clinically asymptomatic elderly subjects had their plasma ADMA levels screened. Those in the highest (high ADMA, n = 15) and lowest quartiles of the ADMA distribution (low ADMA, n = 13) were eligible to receive, in a randomized order, simvastatin (40 mg/day), L-arginine (3 g/day), or a combination of both, each for 3 weeks. Endothelium-dependent vasodilation (EDD) was assessed by brachial artery ultrasound. RESULTS: Simvastatin had no effect on EDD in subjects with high ADMA (6.2 +/- 1.2% vs. 6.1 +/- 0.9%), whereas simvastatin plus L-arginine significantly improved EDD (9.8 +/- 1.5% vs. 5.3 +/- 0.8%; p < 0.01). In subjects with low ADMA, simvastatin improved endothelial function when given alone (9.5 +/- 3.2% vs. 6.1 +/- 3.8%; p < 0.001) or in combination with L-arginine (9.0 +/- 3.1% vs. 6.3 +/- 3.3%; p = 0.001). L-arginine alone improved endothelial function in both groups. Endothelium-independent vasodilation was not affected. CONCLUSIONS: Simvastatin does not enhance endothelial function in subjects with elevated ADMA, whereas it does so in patients with low ADMA. Combination of simvastatin with oral L-arginine improves endothelial function in subjects with high ADMA, but has no additional effect in subjects with low ADMA. As NO-mediated effects may play a major role in the therapeutic effects of statins, ADMA concentration is an important factor that influences the "pleiotropic" effects of simvastatin.     

同型半胱氨酸对人脐静脉内皮细胞eNOS表达及NO含量的影响

目的 通过观察同型半胱氨酸(Hcy)对人脐静脉内皮细胞(HUVECs)一氧化氮合酶(eNOS)表达及NO含量的影响,探讨Hcy诱导动脉粥样硬化形成的病理机制.方法 将体外培养的人脐静脉内皮细胞分为5组,分别加入Hcy0、2.5、5、10及15 mmol/L,培养24h.通过MTT比色法测定细胞活力,采用RT-PCR法检测eNOS mRNA的表达,通过硝酸还原酶法测NO含量.结果 与对照组比较,Hcy(5 ～ 15 mmol/L)剂量处理组细胞活力明显下降(P＜0.05,P＜0.01),eNOS mRNA的表达显著降低(P＜0.01);NO的含量明显下降(P＜0.01),eNOS mRNA的表达变化及NO的含量变化呈现明显的剂量依赖性(P＜0.01).结论 Hcy可通过抑制eNOS mRNA的表达,使eNOS合成减少,活性降低,进而减少HUVECs内NO的生成,这可能是Hcy诱导动脉粥样硬化形成的病理机制之一.     

Preservation of NO production by statins in the treatment of heart failure

OBJECTIVE: Because statins promote endogenous nitric oxide (NO) production in vessels by increasing endothelial nitric oxide synthase (eNOS), we evaluated the clinical benefit and efficiency of simvastatin in preventing the decrease in NO control of coronary blood flow (CBF), NO regulation of myocardial oxygen consumption (MVO(2)) and decreased nitrite production in coronary microvessels, associated with pacing-induced heart failure (HF). METHODS: Dogs (n=17) were instrumented for measurement of coronary blood flow and left ventricular end diastolic pressure (LVEDP). HF was induced by pacing. Ten dogs were given simvastatin 20 mg/kg/day orally (HF+SIMVA) from the 10th day of pacing. RESULTS: HF+SIMVA had a lower LVEDP at 4 weeks of pacing (18+/-1 vs. 25+/-1 mm Hg, p<0.05), and the NO-dependent coronary vasodilation to veratrine was preserved compared to HF (p<0.05). In coronary microvessels, SIMVA potentiated nitrite production compared to HF (p<0.05) and enhanced the NO-dependent decrease in MVO(2) in cardiac tissue in response to 10(-4) mol/l bradykinin, which was markedly blunted in HF (p<0.05). Using Western blotting, there was a reduction in eNOS protein during HF that was preserved at 4-5 weeks of pacing during treatment with SIMVA. CONCLUSIONS: Simvastatin maintained NO production by coronary vessels and NO bioactivity during pacing-induced dilated cardiomyopathy. Targeting the endothelium, which participates in the control of myocardial metabolism by NO, may be an important mechanism of action of statins in the treatment of heart failure.     

停用辛伐他汀对冠心病及冠心病危险因素患者血管内皮功能的影响

目的 观察在冠心病及冠心病危险因素患者中,停用辛伐他汀治疗对血管内皮功能的影响,并探讨相应作用机制。方法 入选33例血清胆固醇（Tc）水平未达标的冠心病及冠心病危险因素患者,分别于基线水平、停药前（即辛伐他汀20mg治疗4周后）及停用辛伐他汀1周时,采用高分辨超声技术检测肱动脉血流介导性扩张（FMD）评估血管内皮依赖性舒张功能,并测定一氧化氮（NO）、血浆内皮素（ET）、6-酮-前列腺素F1α（6-keto-PGF1α）和血栓素B2（TXB2）的水平及主要血脂参数的变化。结果 辛伐他汀治疗4周后可有效降低冠心病及冠心病危险因素患者TC、低密度脂蛋白胆固醇（LDL-C）水平,并明显改善患者肱动脉内皮依赖性舒张功能（FMD）。然而,停用辛伐他汀治疗1周后,所有患者肱动脉内皮依赖性舒张功能均较停药前明显下降（4．82士0．71）％与11．51±0．87％,P〈0．01）,甚至低于未服用辛伐他汀时的基线水平（4．82±0．71％与5．89±0．65％,P〈0．01）,其中冠心病患者停药后FMD下降幅度较仅有冠心病危险因素患者更显著（65．6％与56．3％,P〈0．01）。停药1周后,患者血清NO水平较停药前及基础值均明显降低,而血浆ET水平升高。血浆TXB,水平在停药前后无明显变化。此外,停药后患者血清LDL-C水平虽较治疗4周时有所升高,但仍未恢复至基线水平。停药后肱动脉FMD的变化仅与血清NO降低幅度呈正相关关系（r=0．674。P=0．004）,而与血清LDL-C水平变化无明显相关性（r=-0．414,P=0．083）。结论 在TC水平未达标的冠心病及冠心病危险因素患者中突然终止辛伐他汀治疗可在1周内完全逆转该药对血管内皮功能的改善作用,甚至还可能导致血管内皮功能进一步恶化。并且这种撤药反应随基础疾病的严重性增加。停药所致血管内皮功能损害可能与血管内皮源性的NO减少有关,是非胆固醇依赖性作用。     

前列腺素EI对人脐静脉内皮细胞中NO和eNOS的影响

目的探讨前列腺素EI(prostaglandin EI,PGEI)对内皮细胞一氧化氮(NO)表达和内皮型一氧化氮合酶(eNOS)活性的影响。方法以人脐静脉内皮细胞(HUVEC)为实验对象,检测不同浓度PGEI作用不同时间后,细胞培养上清液和细胞中NO水平的变化,以及细胞eNOS活性的改变。结果(1)随着PGEI浓度的升高,eNOS的活性和NO的含量均逐渐增加(P<0.05);(2)短时间PGEI的干预对eNOS和NO的影响均不明显,24h后细胞中eNOS活性明显升高(P<0.05),NO的含量自12h起随时间延长而增加(P<0.05);(3)用不同PGEI浓度预处理,使TNF-α对eNOS活动的抑制作用减弱。结论PGEI可能通过诱导eNOS的表达,促进NO的释放,且可以重新激活被TNF-α抑制的eNOS活性。     

Sesamin induces nitric oxide and decreases endothelin-1 production in HUVECs: possible implications for its antihypertensive effect

OBJECTIVE: Sesamin has been proved to be antihypertensive. Nitric oxide (NO) is the most important vascular relaxing factor that is regulated in endothelium. Endothelin-1 (ET-1) is characterized as a potent vasoconstrictor and is also regulated in endothelium. Alterations in the endothelial production of NO and ET-1 are known to correlate with hypertension. This study investigated the effect of sesamin on NO and ET-1 in the human umbilical vein endothelial cells (HUVECs). DESIGN: The concentrations of NO and ET-1 in the medium of HUVECs treated by sesamin were measured. The mRNA and protein expressions of nitric oxide synthase (NOS), endothelin converting enzyme-1 (ECE-1), and endothelin-1 (ET-1) were also investigated. Other than the mRNA and protein expression, NOS activity and cyclic GMP (cGMP) were detected. METHODS: The NO concentration was detected by colorimetric assay. The cGMP and ET-1 were analyzed by EIA. The eNOS, ECE-1, and ET-1 mRNA expressions were assayed by Northern blot. The eNOS and ECE-1 protein expressions were analyzed by Western blot. The NOS activity was assayed by detecting the level of [H]-1-citrullin transformed from [H]-1-arginine. RESULTS: Sesamin not only increased the NO concentration in the medium of HUVECs in a dose-dependent manner after 24 h, but also induced eNOS mRNA and protein expressions. NOS activity in the HUVECs was also induced by sesamin. The content of cGMP was induced by sesamin through NO signaling. On the other hand, the ET-1 concentration in the medium of HUVECs treated by sesamin was suppressed in a dose-dependent manner after 24 h. The ECE-1 protein and mRNA expressions were also inhibited by sesamin. However, the mRNA expression of prepro ET-1 was not influenced by sesamin. CONCLUSION: From the above results, it is suggested that sesamin may improve hypertension by its ability to induce NO and inhibit ET-1 production from endothelial cells. The increase of NO by sesamin is through the induction of eNOS gene expression. The decrease of ET-1 by sesamin is through the inhibition of ECE gene expression, but is not through the inhibition of prepro ET-1 gene expression.     

Insulin and lysophosphatidylcholine synergistically stimulate NO-dependent cGMP production in human endothelial cells.

AIMS: Nitric oxide (NO) is an important regulator of cardiovascular homeostasis. Lysophosphatidylcholine (lyso-PC), a major constituent of oxidized low density lipoproteins (oxLDL), has been reported to impair nitric oxide-dependent vasodilatation. This study investigated the possible mechanism of the lyso-PC effect on insulin-stimulated NO-dependent of cyclic guanosine 3',5'-monophosphate (cGMP) generation in human endothelial cells. METHODS: The intracellular concentration of cGMP in cultured human umbilical vein endothelial cells (HUVECs) was used to estimate NO production. The levels of endothelial nitric oxide synthase (eNOS) protein expression were assessed by Western blotting analyses. RESULTS: Both insulin, at physiological concentration, and lyso-PC stimulated rapid and prolonged intracellular of cGMP production, and together induced a marked synergistic response (for short-term stimulation: 1185 +/- 285.9% over control level (100%) compared with insulin and lyso-PC alone (384.8 +/- 67.4% and 357 +/- 205%, respectively; P < 0.001), for long-term stimulation: 3495 +/- 1377%, compared with insulin and lyso-PC alone (663 +/- 131% and 487 +/- 250%, P = 0.002)). Stimulated levels of cGMP accumulation were completely abrogated by NOS inhibitor, indicating NO involvement in the effects of insulin and lyso-PC. Stimulated NO synthesis was not associated with altered eNOS protein expression. Cell subfractionation studies demonstrate that insulin and lyso-PC each alone induced translocation of eNOS from the membrane to the cytosolic compartment and together caused a synergistic translocation. CONCLUSIONS: The presented data suggest that insulin and lyso-PC synergistically upregulate endothelial NO production via eNOS translocation from the membrane fraction to the cytosol. This study raises the possibility that an interplay between various factors accompanying diabetes can lead to endothelial NO overproduction or desensitization of NO-dependent responses. Appropriate rather than necessarily high levels of nitric oxide is the determinant of vascular health.     

Expression and function of recombinant endothelial nitric oxide synthase in human endothelial cells

Endothelial dysfunction is frequently involved in the pathogenesis of vascular disease. While nitric oxide (NO) inhibits smooth muscle cell proliferation, its effect on endothelial cell proliferation is unclear. The aim of this study was to determine if adenoviral-mediated gene transfer of endothelial NO synthase (eNOS) to human umbilical vein endothelial cells (HUVECs) would result in increased generation of NO and affect endothelial cell proliferation. HUVECs were transduced with adenoviral vectors encoding eNOS (AdeNOS) or beta-galactosidase (Ad beta gal) or exposed to diluent (control). AdeNOS-transduced cells showed increased eNOS expression as detected by Western blot analysis, and increased concentrations of cGMP (control 0.7 +/- 0.1; Ad beta gal 0.9 +/- 0.2; AdeNOS 3.1 +/- 0.5 pmol/mg protein; p < 0.001) and nitrite (control 11.8 +/- 1.2; Ad beta gal 13.3 +/- 1.7; AdeNOS 21.1 +/- 2.2 nmol/mg protein/hour; p < 0.01). DNA synthesis as assessed by [(3)H]thymidine incorporation and cell counts were significantly reduced (by approximately 30%) in AdeNOS-transduced HUVECs. Expression of mitogen-activated protein kinase was also decreased in AdeNOS-transduced cells. This study shows that adenoviral-mediated gene transfer of eNOS to HUVECs inhibits endothelial cell proliferation.     

Simvastatin treatment improves liver sinusoidal endothelial dysfunction in CCl4 cirrhotic rats

BACKGROUND/AIMS: Sinusoidal endothelial dysfunction with decreased nitric oxide (NO) production contributes to increased hepatic resistance in cirrhosis. Statins improve endothelial dysfunction in peripheral vasculature. This study was designed to characterize the hemodynamic and molecular effects of statins in cirrhotic rats. METHODS: Systemic and splanchnic hemodynamics were evaluated in CCl(4) ascitic cirrhotic rats treated with placebo or simvastatin (25 mg/kg/day, for 3 days), at baseline and after volume expansion. Vascular responses of liver vasculature were evaluated after isolation and perfusion of the liver. RESULTS: There were no differences in baseline hemodynamics in rats treated with simvastatin or placebo. However, in rats treated with simvastatin the increase in portal pressure induced by volume expansion was significantly attenuated. In isolated and perfused cirrhotic livers simvastatin pre-treatment significantly attenuated the pressure response to methoxamine, and significantly improved paradoxical vasoconstriction induced by acetylcholine. These effects were not observed in the presence of a nitric oxide synthase inhibitor. Simvastatin increased eNOS expression, Akt-dependent eNOS phosphorylation and cGMP liver content. CONCLUSIONS: The administration of simvastatin might constitute a new way to selectively increase NO availability in the cirrhotic liver circulation and, therefore improve the vascular disturbances that contribute to portal hypertension.