醛固酮促进血管紧张素Ⅱ诱导大鼠心脏成纤维细胞合成胶原

为探讨醛固酮对大鼠心脏成纤维细胞血管紧张素Ⅱ 1型受体表达的影响及醛固酮对血管紧张素Ⅱ促进心脏成纤维细胞胶原代谢效应的影响 ,采用3 H 脯氨酸掺入法对体外分离培养的心脏成纤维细胞分别检测醛固酮、血管紧张素Ⅱ以及二者共同作用后对心脏成纤维细胞胶原合成量的影响 ;分别利用放射配体结合实验和半定量逆转录—聚合酶链反应测定经醛固酮处理后细胞血管紧张素Ⅱ 1型受体及其mRNA的表达水平 ,并比较其与对照组间的差异。结果发现血管紧张素Ⅱ (10 -7mol/L)可使心脏成纤维细胞胶原合成量显著增加 (P <0 .0 1) ,醛固酮对心脏成纤维细胞的胶原合成无影响 ,但醛固酮可明显地增强血管紧张素Ⅱ促进心脏成纤维细胞胶原合成的效应 ;经醛固酮 (10 -7mol/L)处理的心脏成纤维细胞血管紧张素Ⅱ 1型受体的表达与对照组比较明显升高 (2倍 ) ,细胞血管紧张素Ⅱ 1型受体mRNA的水平也较对照组显著增加 (1.5倍 )。结果说明醛固酮虽然不能通过直接作用影响心脏成纤维细胞的胶原代谢 ,但它可以通过上调心脏成纤维细胞血管紧张素Ⅱ 1型受体的表达来增强血管紧张素Ⅱ致心脏成纤维细胞胶原合成增多的效应     

血管紧张素Ⅱ对大鼠血管外膜成纤维细胞骨桥蛋白表达的影响

目的研究血管紧张素Ⅱ对培养的大鼠胸主动脉外膜成纤维细胞骨桥蛋白表达的影响。方法大鼠外膜成纤维细胞被随机分为对照组、血管紧张素Ⅱ不同浓度(10-8、10-7、10-6和10-5mol/L)和时间(6h、12h和24h)干预组及血管紧张素Ⅱ加AT1受体拮抗剂氯沙坦和/或AT2受体拮抗剂PD123319干预组,用RT-PCR及Western blotting技术结合光密度扫描分析,观察血管紧张素Ⅱ对培养的大鼠胸主动脉外膜成纤维细胞骨桥蛋白表达的影响。结果血管紧张素Ⅱ10-6mol/L明显刺激外膜成纤维细胞骨桥蛋白的表达,6h、12h和24h桥蛋白较对照组分别升高65.43%、97.03%和105.11%(P<0.05);而24h阴性对照无明显变化。不同浓度的血管紧张素Ⅱ均可诱导骨桥蛋白表达,10-8、10-7、10-6和10-5mol/L管紧张素Ⅱ孵育后分别升高了70.46%、97.37%、123.10%和147.59%(P<0.01)。在血管紧张素Ⅱ刺激前1h分别加入氯沙坦(10-5mol/L)、PD123319(10mmol/L)、氯沙坦(10-5mol/L) PD123319(10mmol/L),共同孵育12h后,其抑制率分别为58.9%、0.92%和59.7%。Western blotting分析,12h不同剂量血管紧张素Ⅱ干预组(10-8、10-7、10-6和10-5mol/L)骨桥蛋白量较对照组分别提高了50.68%、63.03%和69.86%(P<0.05),氯沙坦明显抑制血管紧张素Ⅱ刺激的骨桥蛋白表达,抑制率达到61.7%(P<0.05),而PD123319作用后抑制作用不明显,抑制率仅为0.85%(P>0.05)。结论血管紧张素Ⅱ能在基因和蛋白水平上刺激大鼠外膜成纤维细胞骨桥蛋白的表达,此作用可能是通过AT1受体介导。     

血管紧张素(1-7)对血管紧张素Ⅱ诱导脐静脉内皮细胞表达E-选择素和单核细胞趋化蛋白1的影响

目的 研究血管紧张素(1-7)对血管紧张素Ⅱ诱导的脐静脉内皮细胞E-选择素和单核细胞趋化蛋白1表达的影响,并初步探讨血管紧张素(1-7)的作用机制,阐明血管紧张素(1-7)对血管紧张素Ⅱ在炎症方面的拮抗作用.方法 经形态学及抗VⅢ因子抗体免疫荧光染色鉴定的人脐静脉内皮细胞,按以下分组加入不同干扰因素进行实验.实验分组:①对照组:不加干预因素;②血管紧张素Ⅱ组:加入血管紧张素Ⅱ100 nmol/L;③血管紧张素(1-7)组:加入血管紧张素(1-7)1 000 nmol/L;④血管紧张素Ⅱ+血管紧张素(1-7)组:分别用血管紧张素(1-7)10、100、1 000、10 000 nmol/L预处理30 min后,再加入血管紧张素Ⅱ100 nmol/L;⑤血管紧张素Ⅱ+血管紧张素(1-7)+血管紧张素(1-7)受体拮抗剂A-779组:先用1 000 nmol/L A-779预处理30 min后,再用终浓度为1 000 nmol/L血管紧张素(1-7)预处理30 min,最后加入终浓度100 nmol/L血管紧张素Ⅱ.各组用酶联免疫吸附法和逆转录聚合酶链反应从蛋白和mRNA水平检测E-选择素和单核细胞趋化蛋白1的表达情况.结果 正常细胞生长良好,呈鹅卵石样镶嵌排列,细胞透明度大,轮廓不清.荧光免疫组化染色法,可检测到培养的人脐静脉内皮细胞的VⅢ因子相关抗原为阳性.①与对照组比,血管紧张素Ⅱ(100 nmol/L)使E-选择素(25.39±1.97μg/L)和单核细胞趋化蛋白1(238.71±5.51 ng/L)的蛋白分泌量明显增加, E-选择素和单核细胞趋化蛋白1 mRNA的表达显著升高(均P<0.01);②血管紧张素(1-7)(1 000 nmol/L)使E-选择素(3.72±0.95μg/L)和单核细胞趋化蛋白1(90.24±9.82 ng/L)的蛋白分泌量降低,E-选择素和单核细胞趋化蛋白1 mRNA表达亦降低(均P<0.01);③混合刺激组中血管紧张素(1-7)(10～10 000 nmol/L)减少E-选择素蛋白合成,分别为21.15±1.31、17.41±1.94、12.71±1.84、9.46±1.40μg/L,均低于血管紧张素Ⅱ组(均P<0.01);同时也减少单核细胞趋化蛋白1蛋白合成,分别为214.57±7.16、196.83±8.20、176.63±8.93、155.52±8.19 ng/L,均低于血管紧张素Ⅱ组(均P<0.01);④混合刺激组中,与AngⅡ组比较,血管紧张素(1-7)(10～10 000 nmol/L)呈剂量依赖性的抑制AngⅡ刺激E-选择素、单核细胞趋化蛋白1 mRNA的表达(均P<0.01);⑤加入血管紧张素(1-7)受体拮抗剂A-779后,血管紧张素(1-7)的作用消失.结论 血管紧张素(1-7)通过其特异性受体Mas拮抗血管紧张素Ⅱ诱导的人脐静脉内皮细胞E-选择素和单核细胞趋化蛋白1的表达,并呈浓度依赖性.     

罗格列酮对血管紧张素Ⅱ诱导血管平滑肌细胞增殖的影响

目的 探讨罗格列酮对血管紧张素Ⅱ诱导血管平滑肌细胞增殖的影响及可能的机制.方法 原代培养大鼠血管平滑肌细胞,取第4～8代细胞进行实验.用终浓度为1 μmol/L血管紧张素Ⅱ诱导6 h,随机分成对照组(含10% FBS的DMEM培养基)、1 μmol/L血管紧张素Ⅱ组、不同浓度罗格列酮(20、30、40及50μmol/L) 干预组,30 μmol/L罗格列酮干预不同时间组 (6、12、18及24 h).分别采用MTT和流式细胞术观察血管平滑肌细胞增殖和增殖周期的变化;逆转录聚合酶链反应和免疫印迹法测定不同干预条件下血管平滑肌细胞血管紧张素Ⅱ2型受体mRNA和蛋白的表达水平.结果 血管紧张素Ⅱ组吸光值明显高于对照组(P<0.01),20、30、40及50μmol/L罗格列酮干预12 h及30μmol/L 罗格列酮干预6、12、18及24 h后,吸光值明显降低(P<0.05或P<0.01);血管紧张素Ⅱ组增殖指数和S期细胞分数明显高于对照组(P<0.01).随着罗格列酮干预浓度的增加或干预时间的延长,增殖指数、S期细胞分数及处于S期分数均明显下降(P<0.05或P<0.01).与血管紧张素Ⅱ组相比,不同浓度(20、30及50μmol/L)罗格列酮干预12 h及同一浓度(30μmol/L)干预不同时间(6、12及24 h)显著升高血管紧张素Ⅱ2型受体mRNA和蛋白的表达(P<0.05或P<0.01).结论 罗格列酮至少部分通过上调血管紧张素Ⅱ2型受体表达,阻止血管平滑肌细胞从G0/G1期向S期、G2/M期转化,从而抑制血管紧张素Ⅱ诱导血管平滑肌细胞的增殖、迁移,发挥血管保护作用.     

血管紧张素1-7抑制血管外膜成纤维细胞增殖

目的探讨血管紧张素1-7对血管外膜成纤维细胞增殖的影响.方法在培养大鼠血管外膜成纤维细胞中,用血管紧张素Ⅱ和血管紧张素1-7刺激,检测蛋白激酶C、丝裂素活化蛋白激酶及钙调神经磷酸酶活性,以氚标胸腺嘧啶和氚标亮氨酸掺入量反映血管外膜成纤维细胞增殖的指标.结果血管紧张素1-7既能明显抑制基础状态下血管外膜成纤维细胞蛋白激酶C、丝裂素活化蛋白激酶和钙调神经磷酸酶活性(P＜001或P＜0.05),又能抑制血管紧张素Ⅱ刺激下的血管外膜成纤维细胞蛋白激酶C、丝裂素活化蛋白激酶和钙调神经磷酸酶活性(P＜0.01或P＜0.05).血管紧张素1-7能明显抑制血管外膜成纤维细胞氚标胸腺嘧啶和氚标亮氨酸掺入(P＜0.01或P＜0.05);而血管紧张素Ⅱ则促进血管外膜成纤维细胞氚标胸腺嘧啶和氚标亮氨酸掺入(P＜0.01或P＜0.05).血管紧张素1-7还能抑制血管紧张素Ⅱ刺激下的血管外膜成纤维细胞氚标胸腺嘧啶和氚标亮氨酸掺入(P＜0.01或P＜0.05).结论血管紧张素1-7可能通过影响蛋白激酶C、丝裂素活化蛋白激酶和钙调神经磷酸酶信号通路,发挥抑制血管外膜成纤维细胞增殖的作用.     

HIP-55介导血管紧张素Ⅱ诱导的血管胶原沉积

目的探究HIP-55是否介导血管紧张素Ⅱ诱导的血管胶原沉积。方法生物信息学分析的方法预测HIP-55是否参与血管紧张素Ⅱ(AngⅡ)诱导的血管重构,小鼠背部皮下埋入AngⅡ(1 mg·kg~(-1)·d~(-1))微量泵14 d诱导血管重构模型,利用无创血压仪检测小鼠血压变化,蛋白质印迹法(Western blot)、反转录聚合酶链式反应(RT-PCR)检测HIP-55在血管重构模型中的表达变化情况。并构建HIP-55基因敲除小鼠,将小鼠分为4组:野生/假手术组(WT/Sham组)、HIP-55基因敲除/假手术组(HIP-55~(-/-)/Sham组)、野生/埋泵组(WT/AngⅡ组)和HIP-55基因敲除/埋泵组(HIP-55~(-/-)/AngⅡ组),主动脉苏木素-伊红(HE)染色,Masson染色检测血管形态变化及胶原沉积变化。结果生物信息学提示HIP-55可能参与AngⅡ诱导的血管重构。与对照组相比,实验组小鼠血管胶原沉积显著增加(3.1±0.18比1.1±0.04,P<0.01)、血管横切平均面积显著增加(2.7±0.1比1.0±0.04,P<0.01)、平均厚度明显增加[(105.7±7.0)μm比(66.0±7.6)μm,P<0.01]、平均厚度/内径明显增加(0.28±0.01比0.17±0.01,P<0.01)。实验组小鼠血管中HIP-55 mRNA(1.6±0.22比1.0±0.03,P<0.01)和HIP-55蛋白(1.6±0.15比1.0±0.04,P<0.01)表达水平均明显增加。与WT/Sham组相比,HIP-55~(-/-)/Sham组小鼠的血管胶原沉积水平无明显变化(1.1±0.04比1.0±0.05,P=0.70);给予AngⅡ埋泵后,与WT/AngⅡ组相比,HIP-55~(-/-)/AngⅡ组小鼠的血管胶原沉积明显减少(2.6±0.2比3.3±0.1,P<0.05)。结论 HIP-55介导AngⅡ诱导的血管胶原沉积。     

血管紧张素(1～7)对血管加压素诱导心脏成纤维细胞增殖的影响及其与钙调神经磷酸酶的关系

目的探讨血管紧张素(1～7)[Ang(1～7)]对血管加压素(AVP)诱导心脏成纤维细胞(CFs)增殖的影响及其与钙调神经磷酸酶(CaN)的关系.方法分离培养SD仔鼠CFs,四氮唑盐(MTT)比色法检测细胞增殖,采用流式细胞分析仪技术测定细胞周期,发色底物法测定细胞内CaN的活性.结果 (1)10-7 mol/L AVP干预24 h后,CFs的MTT吸光度值(0.24±0.01)较对照组(0.14±0.01)明显增高(P<0.01);给予10-9～10-6 mol/L Ang(1～7)和AVP共同干预后,CFs的吸光度值呈递减趋势,分别为0.22±0.01、0.21±0.01、0.18±0.01和0.16±0.01,均较AVP组降低,差异有统计学意义(P<0.01).(2)AVP刺激后, CFs 的S期百分率(14.00±0.94)和增殖指数(23.4±1.8)较对照组(分别为5.4±0.7和10.8±2.4)明显增高(P<0.01);10-7 mol/L Ang(1～7) 和AVP共同作用后S期百分率(8.5±0.7)和增殖指数(16.2±2.0)较AVP组降低,差异有统计学意义(P<0.01).(3)AVP组CFs内CaN活性(0.27±0.02 kU/mg)较对照组(0.12±0.01)kU/mg明显增加(P<0.01),给予10-9～10-6 mol/L Ang(1～7) 和AVP共同干预后,CaN活性分别为0.25±0.01、0.20±0.02、0.17±0.01和0.15±0.02(kU/mg),均较AVP组降低,差异有统计学意义(P<0.01).结论 Ang(1～7)能抑制AVP诱导CFs增殖,CaN活性降低可能是其分子生物学机制之一.     

血管紧张素Ⅱ、血管紧张素(1-7)对NIT-1细胞胰岛素信号通路的影响

目的 研究血管紧张素Ⅱ、血管紧张素(1-7)对胰岛β细胞胰岛素信号通路的影响.方法 小鼠胰岛β细胞株NIT-1予(1)0、10-7、10-6、10-5和10-4 mol/L浓度血管紧张素Ⅱ处理24h;(2)0、10-7、10-6、10-5和10-4mol/L浓度血管紧张素(1-7)处理24h;(3)血管紧张素Ⅱ、血管紧张素(1-7)联合处理24h,分为对照、10-5 mol/L血管紧张素Ⅱ、10-6 mol/L血管紧张素(1-7)、10-5 mol/L血管紧张素Ⅱ+10-6 mol/L血管紧张素(1-7)组.Western印迹检测胰岛素受体β亚基酪氨酸磷酸化(IR-β-Tyr)及蛋白激酶β丝氨酸磷酸化(Akt-Ser)水平.结果 血管紧张素Ⅱ浓度10-5和10-4mol/L时,胰岛素刺激的IR-β-Tyr、Akt-Ser表达显著降低;不同浓度血管紧张素(1-7)作用下,胰岛素刺激的IR-β-Tyr、Akt-Ser表达与对照组相比无差异;加入血管紧张素(1-7)共同孵育可逆转血管紧张素Ⅱ对Akt-Ser表达的抑制,而血管紧张素Ⅱ对IR-β-Tyr表达的抑制无效应.结论 在β细胞中,血管紧张素Ⅱ抑制胰岛素信号传导,血管紧张素(1-7)可拮抗血管紧张素Ⅱ对胰岛素刺激的Akt-Ser的抑制.     

血管紧张素Ⅱ和醛固酮对心脏成纤维细胞Ⅲ型胶原mRNA表达的影响

目的　研究肾素 血管紧张素 醛固酮系统 (RAAS)的效应激素血管紧张素Ⅱ (ANGⅡ )和醛固酮 (ALD)对培养的心脏成纤维细胞Ⅲ型胶原mRNA表达的影响。方法　用RT PCR的方法检测原代培养心脏成纤维细胞Ⅲ型胶原mR NA表达。结果　ANGⅡ (10 - 8mol L)和ALD(10 - 8mol L)分别能促进心脏成纤维细胞Ⅲ型胶原mRNA表达 ,其各自的受体拮抗剂可分别拮抗它们的作用。结论　ANGⅡ和ALD可直接促进Ⅲ型胶原在心肌间质沉积 ,在心室重塑的病理生理过程中扮演重要角色。应用ANGⅡ和ALD的受体拮抗剂可抑制心肌纤维化 ,预防心室重塑的发生。     

重组人松弛素体外调节血管紧张素Ⅱ诱导的大鼠心肌纤维化

目的:观察在重组人松弛素(rhRLX)及血管紧张素Ⅱ(AngⅡ)作用下对心脏成纤维细胞功能(CFs)的影响。方法:原代培养Sprague-Dawley大鼠心脏成纤维细胞,经AngⅡ(10-6mmol/L)单独作用及AngⅡ加rhRLX(100μg/L)共同作用后,用MTT比色法测定CFs的增殖;用ELISA法检测Ⅰ型前胶原羧基末端肽(PⅠCP)和Ⅲ型前胶原氨基末端肽(PⅢNP)的水平。结果:rhRLX可显著抑制AngⅡ促进CFs增殖,并拮抗AngⅡ促进CFs分泌PⅠCP的作用。结论:rhRLX能够改善AngⅡ诱导的心肌纤维化。     

Angiotensin II Receptors and Angiotensin II-Stimulated Signal Transduction

Originally known to be a vasoconstrictor and thought to play a critical role in hypertension, angiotensin II has recently emerged to be important in inflammation, atherosclerosis, and congestive heart failure. The discovery of selective angiotensin II receptor antagonists has enabled specific functions to be assigned to at least three angiotensin receptor subtypes (AT1, AT2, and AT4 receptors), which are expressed in a tissue-specific manner. Use of these antagonists resulted in the cloning and sequencing of two angiotensin II receptors (AT1 and AT2), which enabled a molecular analysis of angiotensin II binding sites to be performed. With these tools it has become possible to characterize the multiple signal transduction pathways activated by angiotensin II in a receptor- and tissue-specific manner. Initial studies have focused on the AT1 receptor inhibited by losartan and have defined structural domains responsible for G-protein coupling, activation of phospholipase C, and interactions with tyrosine kinases. Three major intracellular signal pathways associated with the AT1 receptor are activation of tyrosine kinases and downstream kinase cascades, stimulation of phospholipase C and increases in intracellular calcium, and inhibition of adenyl cyclase. Recent data show that angiotensin II not only stimulates cytoplasmic tyrosine kinases, including c-Src, focal adhesion kinase (FAK), and Janus kinases (JAK2 and TYK2), but also may transactivate receptor tyrosine kinases such as EGF Axl and PDGF by as yet undefined autocrine mechanisms. These angiotensin II-stimulated signal cascades appear to be required for angiotensin II effects such as vasoconstriction, proto-oncogene expression, protein synthesis, and cell proliferation. Advances in our knowledge of angiotensin II-mediated signaling events, especially those related to stimulation of kinase activity, may aid in development of new therapies for cardiovascular diseases.     

氯沙坦对血管平滑肌细胞内单核细胞趋化因子-1表达的影响

为了探讨血管紧张素Ⅱ受体拮抗剂氯沙坦对血管平滑肌细胞内单核细胞趋化蛋白 1表达的影响 ,以培养幼兔主动脉平滑肌细胞为研究对象 ,分别给予不同浓度血管紧张素Ⅱ和 或血管紧张素Ⅱ受体拮抗剂氯沙坦 ,采用免疫组织化学、原位杂交与酶联免疫吸附技术检测不同处理组平滑肌细胞内单核细胞趋化蛋白 1蛋白及其mR NA表达和平滑肌细胞培养介质中单核细胞趋化蛋白 1含量的变化。结果发现 ,10 - 6 ～ 10 - 1 0 mol L血管紧张素Ⅱ呈剂量依赖性地增加平滑肌细胞内单核细胞趋化蛋白 1蛋白及其mRNA表达水平 ,增高培养介质中单核细胞趋化蛋白 1蛋白含量 (P均 <0 .0 0 1)。 10 - 5 ～ 10 - 7mol L氯沙坦预处理使血管紧张素Ⅱ刺激的平滑肌细胞内单核细胞趋化蛋白 1蛋白及其mRNA表达水平及培养介质中单核细胞趋化蛋白 1蛋白含量明显减低 (P均 <0 .0 0 1)。以上结果提示 ,氯沙坦可拮抗血管紧张素Ⅱ所致的平滑肌细胞内单核细胞趋化蛋白 1的表达与分泌 ,这可能有助于减轻或防治某些病理状态下血管平滑肌细胞的增殖与迁移。     

Human Angiotensin II Receptors are Regulated By Angiotensin II

Specific angiotensin II (ANG II) binding on human platelets in man was measured to examine ANG II receptor regulation in man. Eight normal volunteers received either a high, or a low sodium diet, or a low sodium diet together with the ANG I converting enzyme inhibitor enalapril. The following parameters were determined at the end of each study period: ANG II platelet receptor binding capacity (B_max) and dissociation constant (K_D); plasma-ANG II, plasma renin, plasma-aldosterone, plasma-atrial natriuretic peptide; and blood pressure (BP) increase to graded doses of i.v. given ANG II. Plasma ANG II (6±0.5, 21±4, 8±1 fmol/ml) and B_max (14±2, 5±1, 10±2 sites/cell) changed in a reciprocal fashion on a high, low or low sodium diet with enalapril respectively. Plasma concentration of atrial natriuretic peptide was unchanged on a low sodium intake and consistently decreased when enalapril was added to the low sodium regimen. BP increase to 4 ng ANG II/kg/min was 27±3, 10±1, and 24±5 mmHg during the three study periods respectively. The data suggest that ANG II regulates maximal capacity of platelet ANG II binding. Therefore, regulation of platelet ANG II binding sites goes in parallel with, and may serve as index for, ANG II receptors on vascular smooth muscle, but ANG II receptor regulation is apparently different in adrenal cells.     

Functional Angiotensin Receptor on Cultured Bovine Chromaffin Cells: Secretory Response to Angiotensin II and Angiotensin III

ABSTRACT

The adrenal medulla responds in vivo to exogenous angiotensin II by secreting catecholamines. We previously reported that an angiotensin receptor is present on cultured bovine chromaffin cells and mediates secretion of adrenal catecholamines. The present report examines whether the bovine chromaffin cell receptor responds to angiotensin III. We show in this report that angiotensin III is nearly equiactive with angiotensin II as a secretagogue in these cultured cells.     

Angiotensin II Antagonists

Acute blockade of the renin-angiotensin system with the parenterally active angiotensin II antagonist saralasin has been shown to effectively lower blood pressure in a large fraction of patients with essential hypertension and to improve hemodynamics in some patients with congestive heart failure. It is now possible to antagonize chronically angiotensin II at its receptor using the non-peptide angiotensin I1 inhibitor losartan (DuP 753, MK 954). When administered by mouth, this compound induces a dose-dependent inhibition of the pressor response to exogenous angiotensin 11. This effect is closely related to circulating levels of the active metabolite E3174. Preliminary studies performed in hypertensive patients suggest that losartan has a blood pressure lowering action equivalent to that of an ACE inhibitor. Whether this compound will compare favorably with ACE inhibitors requires however further investigation.     

转换酶抑制剂、血管紧张素受体阻滞剂与心房颤动

心房颤动(Af)为最常见的心律失常,常与心血管发病率和死亡率相关,Af常常需要触发机制诱发及有利的电生理或解剖底物维持,近年对触发Af底物发展这一新的治疗策略产生了兴趣,基础和临床试验资料提示调节肾素-血管紧张素-醛固酮系统(RAAS)或许可减少心脏重塑和Af,现对RAAS抑制剂治疗和预防Af的机制、基础和临床研究结果以及正在进行的临床研究等进行简要综述。     

转染血管紧张素Ⅱ1型受体反义核苷酸对血管外膜成纤维细胞增殖的影响

为了评价转染血管紧张素Ⅱ1型受体反义核苷酸对血管外膜成纤维细胞血管紧张素Ⅱ受体亚型mRNA表达,及细胞内核酸蛋白质的合成水平的作用。采用逆转录－聚合酶链反应克隆血管紧张素Ⅱ1型受体cDNA序列（476bp),将克隆cDNA反向插入PLXSN,构建一完整的含血管紧张素Ⅱ1型受体的质粒,并转染入培养的血管外膜成纤维细胞,逆转录－聚合酶链反应和免疫印迹鉴定其转染后血管紧张素Ⅱ1型受体mRNA和蛋白表达。比较血管紧张素Ⅱ10^-7mol/L刺激24h后的转染及非转染的血管外膜成纤维细胞血管素Ⅱ受体各亚型mRNA表达、细胞内核酸蛋白质的合成水平。转染组血管紧张素Ⅱ1型受体mRNA和蛋白表达量显著减少,对照组相比差异显著（P＜0．01）。血管紧张素Ⅱ10^-7mol/L刺激24h后,与对照组血管外膜成纤维细胞相比,转染组血管紧张素Ⅱ1型受体mRNA表达明显减少,血管紧张素Ⅱ受体Ⅱ型mRNA表达明显增加（P＜0．01）,但两组间核酸和蛋白合成均无显著差异（P＞0．05）。提示反义核苷酸封闭后,血管外膜成纤维细胞血管紧张素Ⅱ1型受体mRAN表达显著抑制,同时血管紧张素Ⅱ受体Ⅱ型mRNA上调。单纯封闭血管紧张素Ⅱ1型受体mRNA并不能有效阻断血管紧张素Ⅱ介导的血管外膜成纤维细胞生长。     

Genetics of Angiotensin I-Converting Enzyme

The ACE gene is constitutively expressed in several types of somatic cells, including vascular cells. A soluble form of the enzyme is secreted in plasma by proteolytic cleavage of the membrane anchor. The interindividual variability in plasma ACE levels is very large, and a family study has indicated that it was under the influence of a major gene polymorphism. An insertion (I) deletion (D) polymorphism in intron 16 of the ACE gene was then found to be associated with plasma and cellular ACE levels. The D allele, wich is associated with higher plasma ACE levels, and the level of ACE in plasma, were found in case control studies to be associated with an increased risk of myocardial infarction, an increased risk of diabetic nephropathy in type I diabetic patients, and a faster rate of renal function degradation in glomerular diseases. Although these findings should be confirmed in prospective studies, they can support the concept that ACE level is a critical factor in the determinism of angiotensins and kinins (and perhaps also other peptide substrates) levels in peripheral circulations and in tissue interstitium, especially in the heart and kidney.     

Angiotensin II-mediated microvascular thrombosis

Hypertension is associated with an increased risk of thrombosis that appears to involve an interaction between the renin-angiotensin system and hemostasis. In this study we determined whether angiotensin II-mediated thrombosis occurs in arterioles and/or venules and assessed the involvement of type 1 (AT?), type 2 (AT?), and type 4 (AT?) angiotensin II receptors, as well as receptors for endothelin 1 and bradykinin 1 and 2 in angiotensin II-enhanced microvascular thrombosis. Thrombus development in mouse cremaster microvessels was quantified after light/dye injury using the time of onset of the thrombus and time to blood flow cessation. Wild-type and AT? receptor-deficient mice were implanted with an angiotensin II-loaded ALZET pump for 2 weeks. Angiotensin II administration in both wild-type and ATAT? receptor-deficient mice significantly accelerated thrombosis in arterioles. Genetic deficiency and pharmacological antagonism of AT? receptors did not alter the thrombosis response to angiotensin II. Isolated murine platelets aggregated in response to low (picomolar) but not high (nanomolar) concentrations of angiotensin II. The platelet aggregation response to angiotensin II depended on AT? receptors. Antagonism of AT? receptors in vivo significantly prolonged the onset of angiotensin II-enhanced thrombosis, whereas an AT? receptor antagonist prolonged the time to flow cessation. Selective antagonism of either endothelin 1 or bradykinin 1 receptors largely prevented both the onset and flow cessation responses to chronic angiotensin II infusion. Our findings indicate that angiotensin II induced hypertension is accompanied by enhanced thrombosis in arterioles, and this response is mediated by a mechanism that involves AT?, AT?, bradykinin 1, and endothelin 1 receptor-mediated signaling.