内皮素1及其受体在肺动脉高压发病机制中作用的研究进展

内皮素1能够引起血管收缩、刺激平滑肌细胞增殖和血管重塑。越来越多的研究证明,MAPK/NF-κB信号转导通路激活能够诱导内皮素受体上调,导致肺动脉血管对内皮素1的刺激呈现高敏感性和高反应性,从而增强肺动脉血管收缩、甚至引起肺动脉血管痉挛,在肺动脉高压等心血管疾病的发生和发展中扮演了重要角色。本文将综述内皮素1及其受体在肺动脉高压发病中作用的研究进展,着重探讨内皮素受体上调与肺动脉血管高敏感性、高反应性的关系,展望在细胞内MAPK/NF-κB信号转导通路水平上,抑制肺动脉血管内皮素受体的表达、改善肺动脉高敏感性和高反应性,为治疗肺动脉高压提供新的策略和药物治疗新靶点。     

同型半胱氨酸通过YAP通路调控大鼠冠状动脉血管平滑肌细胞高反应性的作用机制研究

背景冠状动脉血管平滑肌细胞(VSMC)高反应性是导致冠状动脉痉挛的关键,而高同型半胱氨酸(Hcy)能诱导冠状动脉痉挛,但其具体作用机制尚不完全清楚。目的探讨Hcy通过YAP通路调控冠状动脉VSMC高反应性的作用机制。方法 2018年1—10月,将SD大鼠实施安乐死后在无菌环境中迅速去除心脏并制成长1.0～1.5 mm血管环。将新鲜的冠状动脉血管环作为A组;在37℃、5%CO2条件下,将在DMEM低糖培养基中培养的冠状动脉血管环作为B组,将在Hcy+DMEM低糖培养基中培养的冠状动脉血管环作为C组,将在维替泊芬(VP)+DMEM低糖培养基中培养的冠状动脉血管环作为D组,将在Hcy+VP+DMEM低糖培养基中培养的冠状动脉血管环作为E组;除A组外冠状动脉血管环均培养24 h。采用微血管张力检测仪检测内皮素B型受体激动剂蛇毒类似物(S6c)和内皮素1(ET-1)诱导的冠状动脉血管张力,采用Western blot法检测内皮素A型(ETA)受体、内皮素B型(ETB)受体、YAP、磷酸化ERK1/2(p-ERK1/2)、ERK1/2、磷酸化mTOR(p-mTOR)、mTOR、磷酸化AMPK(p-AMPK)、AMPK及Sirt1的表达水平。结果 (1)Hcy可增强S6c和ET-1呈浓度依赖方式介导的冠状动脉血管收缩。C组冠状动脉血管环的ETA受体/β-actin、ETB受体/β-actin及YAP/β-actin高于A组和B组,B组冠状动脉血管环的ETB受体/β-actin及YAP/β-actin高于A组(P0.05)。(2)VP能有效抑制由Hcy上调的S6c和ET-1呈浓度依赖方式介导的冠状动脉血管收缩。C组大鼠冠状动脉血管环ETA受体/β-actin、ETB受体/β-actin及YAP/β-actin高于B、D、E组(P0.05)。(3)C组冠状动脉血管环p-ERK1/2/ERK1/2、p-mTOR/mTOR高于B、D、E组(P0.05);B组冠状动脉血管环p-ERK1/2/ERK1/2高于D组,p-AMPK/AMPK及Shirt1/β-actin高于C、D、E组(P0.05)。结论 Hcy可能通过YAP通路激活ERK1/2和mTOR信号通路,上调VSMC内皮素受体,进而增强冠状动脉VSMC高反应性,这将为高Hcy致冠状动脉痉挛的具体作用机制研究提供新的理论依据。     

冠状动脉痉挛病人的食管痉挛

许多观察认为,冠状动脉痉挛是血管平滑肌的一种局部现象,通常与冠状动脉粥样硬化有关。某些病人尚同时合并有雷诺氏现象和周期性偏头痛,提示冠状动脉痉挛是全身血管平滑肌收缩增强综合征的表现     

α1-肾上腺素受体与肺动脉高压

本文综述了α1-肾上腺素受体在肺动脉高压形成中的作用。低氧或血管壁张力改变均可引起α1-肾上腺素受体基因转录增加,受体密度增高,敏感性增强;去甲肾上腺素,食欲抑制药,可卡因等通过兴奋α1-肾上腺素受体,可引起肺血管平滑肌收缩,增殖,导致肺动脉高压。     

神经肽Y受体与高血压研究进展

神经肽Ｙ三种受体在心脏，血管上有广泛的分布，它除具有直接收缩血管的作用外还能增强缩血管物质的作用，抑制舒血管物质的活性，促进血管平滑肌细胞的增生，使脱敏的α受体恢复敏感性等功能，从而引起外周血管阻力增加，在高血压的发病机理中占有一定的地位。     

血管平滑肌反应的增强和内皮依赖性松弛的障碍促使冠脉痉挛

为了搞清楚局部冠(状动)脉过度收缩的本质,作者报道组胺造成冠脉痉挛的病理生理特征,着重探讨:(1)高胆固醇血症和/或血管内膜增厚在冠脉痉挛中的作用,(2)离体灌注心脏冠脉过度收缩的机制,(3)血管内皮及平滑肌功能在组胺引起冠脉收缩中的作用。方法动物模型:36只 G(?)ttingen 小型     

ROCK抑制剂治疗心血管疾病的研究进展

ROCK为Rho相关的卷曲蛋白激酶,其表达上调常引起平滑肌细胞收缩异常,导致冠状动脉痉挛、动脉粥样硬化、心肌肥厚和肺动脉高压等,因此ROCK抑制剂对这些心血管疾病的发生发展有一定抑制作用,但临床应用尚需更多的研究来证实,本文就ROCK抑制剂在心血管疾病的应用作一综述。     

内皮素与胃粘膜损伤

内皮素与胃粘膜损伤关系密切。在各种急性胃粘膜损伤模型中均出现血浆或胃粘膜内皮素水平的升高,局部血管或粘膜下应用内皮素可致胃粘膜损伤,应用内皮素抗体,受体拮抗剂或干扰内皮素合成可减轻应激所致的胃粘膜损伤,通过收缩血管,增加渗出并减少循环血量而降低胃粘膜血流是内皮素的主要作用机制,另外,它还可影响胃壁平滑肌收缩和胃酸分泌,作用于中枢神经系统,通过迷走神经增强胃运动和胃内压也可能是其机制之一。     

内皮素与胃粘膜损伤

内皮素与胃粘膜损伤关系密切。在各种急性胃粘膜损伤模型中均出现血浆或胃粘膜内皮素水平的升高,局部血管或粘膜下应用内皮素可致胃粘膜损伤,应用内皮素抗体、受体拮抗剂或干扰内皮素合成可减轻应激所致的胃粘膜损伤。通过收缩血管、增加渗出并减少循环血量而降低胃粘膜血流是内皮素的主要作用机制,另外,它还可影响胃壁平滑肌收缩和胃酸分泌,作用于中枢神经系统,通过迷走神经增强胃运动和胃内压也可能是其机制之一。     

血管紧张素Ⅱ2型受体基因可调控体外培养的血管平滑肌细胞基质金属蛋白酶2的表达

目的利用强力霉素—开放可调控哺乳动物表达系统,对体外培养血管平滑肌细胞的血管紧张素Ⅱ2型受体表达进行有效调控,在此基础上对基质金属蛋白酶2的表达受血管紧张素Ⅱ及其受体拮抗剂的影响进行研究。方法建立强力霉素可调控表达血管紧张素Ⅱ2型受体基因的双重稳定大鼠血管平滑肌细胞。观察该血管平滑肌细胞中血管紧张素Ⅱ2型受体受调控表达情况,以及血管紧张素Ⅱ及其1型、2型其受体拮抗剂干预上述细胞后基质金属蛋白酶2的表达情况变化。结果强力霉素—开放可调控哺乳动物表达系统可成功介导血管紧张素Ⅱ2型受体基因在原代培养大鼠主动脉血管平滑肌细胞的表达,该表达受到强力霉素给予/去除的紧密调控;强力霉素干预可在48h内迅速诱导该血管平滑肌细胞表达血管紧张素Ⅱ2型受体,该表达在强力霉素干预后72h进一步增强(P<0.01)。血管紧张素Ⅱ2型受体基因的可调控表达抑制由于血管紧张素Ⅱ干预后引起的基质金属蛋白酶2表达的增强(P<0.01)。这一作用被血管紧张素Ⅱ1型受体拮抗剂进一步增强(P<0.01);而被加入2型受体拮抗剂干预取消;同时给予上述两种拮抗剂时基质金属蛋白酶2的表达与基础状态时的情况一致。结论血管紧张素Ⅱ干预增强基质金属蛋白酶2的表达,该作用是通过血管紧张素Ⅱ1型受体介导的;经强力霉素诱导表达血管紧张素Ⅱ2型受体基因可以明显抑制这一生物学作用,说明血管紧张素Ⅱ2型受体基因经诱导后表达可以有效调控血管平滑肌细胞细胞外基质合成和降解。     

Endothelin-1 synthesis and endothelin B receptor expression in human coronary artery smooth muscle cells and monocyte-derived macrophages is up-regulated by low density lipoproteins

Endothelin-1 (ET-1) is a potent vasoconstrictive peptide exerting its effects predominantly by paracrine and autocrine mechanisms. ET-1 acts as a mitogen and co-mitogen on vascular smooth muscle cells, and accumulating evidence suggests that ET-1 is involved in the pathogenesis of atherosclerosis. Deposition of low density lipoproteins (LDL) in the vessel wall is known to play a crucial role in the development of atherosclerotic lesions. In the present study, we have investigated the effect of native LDL (nLDL) and oxidatively modified LDL (oxLDL) on ET-1 synthesis and endothelin receptor expression in cultured human coronary artery smooth muscle cells and human monocyte-derived macrophages. Native LDL and oxLDL induced a significant stimulation of ET-1 release and ET-1 mRNA expression in human coronary artery smooth muscle cells and monocyte-derived macrophages. Antibodies against the scavenger receptor CD36 significantly reduced the oxLDL-induced stimulation of ET-1 synthesis. The antioxidants trolox and probucol did not significantly inhibit the LDL-induced rise of ET-1 release. Endothelin B receptor expression was up-regulated in both cell types after incubation with nLDL and oxLDL. In coronary smooth muscle cells, endothelin A receptor expression was slightly increased by LDL, whereas endothelin A receptor was not detectable in monocyte-derived macrophages. Coronary artery smooth muscle cells secreted a more than 150-fold higher amount of immunoreactive ET-1 into the cell culture medium than monocyte-derived macrophages. In summary, the present data, demonstrating a LDL-induced up-regulation of the endothelin system in coronary smooth muscle cells and in monocyte-derived macrophages, provide further support for a pathophysiological role of endothelin in coronary atherosclerosis and suggest that ET-1 might be involved in mediating the atherogenic effects of LDL.     

The potential role of endothelin as a vasoconstrictor substance in congestive heart failure.

A rapidly growing body of data supports the concept of in situ regulation of vascular tone: the ability of vasoactive substances to regulate vascular tone at their site of production within the wall of the vasculature. Sufficient data exist to suggest that ineffective production or response to endothelium-dependent vasodilator substances, or excessive production or responsiveness to endothelium-dependent vasoconstrictor substances may play an important role in cardiovascular disorders such as hypertension, coronary artery spasm, restenosis following coronary angioplasty, and congestive heart failure. The present review summarizes data which support the concept that endothelin, a potent vasoconstrictor produced by the endothelium, may play a role in the excessive vasoconstriction of heart failure. Increased circulating plasma endothelin may be particularly relevant to the range of pulmonary vasoconstriction encountered in congestive heart failure, with a correlation revealing that the greatest increase of plasma endothelin occurs in patients with marked pulmonary hypertension within the congestive heart failure patients studied.     

Endothelin activates the dihydropyridine-sensitive, voltage-dependent Ca2+ channel in vascular smooth muscle.

Endothelin is a potent endothelium-derived vasoconstrictor peptide recently characterized from porcine and human vascular endothelial cells. Here we provide evidence that endothelin activates the dihydropyridine-sensitive, voltage-dependent Ca2+ channel in porcine coronary artery smooth muscle. The vasoconstrictor action of endothelin is efficiently antagonized by low doses of the dihydropyridine Ca2+-channel blocker nicardipine. Endothelin augments the Ca2+-induced contraction in a high-K+ depolarizing solution, markedly enhances high-threshold Ca2+-channel current on the whole-cell patch clamp recording, and causes a sustained increase in the intracellular Ca2+ that is largely dependent on extracellular Ca2+. These findings suggest that endothelin exerts its vasoconstrictor effect by either directly or indirectly activating the voltage-dependent Ca2+ channel.     

The upregulation of endothelin and its receptors in porcine coronary arteries in a double balloon injury model of restenosis

Endothelin, a potent vasoconstrictor, mitogen, and stimulant of collagen synthesis, is reported to be increased after vascular injury. We tested the hypothesis that tissue endothelin levels and its receptor expression are increased following double balloon injury in a porcine coronary artery model of restenosis. Male miniature swine maintained on a hyperlipidemic diet underwent oversized balloon injury to both the proximal right coronary artery and left circumflex coronary artery. Two weeks following the initial injury, the arteries were repeat injured at the same site and subsequently harvested four weeks later. Proximal balloon injured (BI) and distal non-balloon-injured (NBI) segments from the same artery were collected. Tissue endothelin-1 (ET-1) levels were measured by ELISA. Endothelin receptors were assayed by radioligand binding using ¹²⁵I-ET-1 and also immunolabeling. Tissue endothelin levels were 4–5 fold greater in BI arteries as compared to NBI. There was a significant increase in tissue ET-1 levels and endothelin receptor binding following double balloon injury relative to NBI control arteries. Western blots showed an increase expression of ET_A receptor protein in injured vessels compared to non-injured arteries. Immunohistochemistry using an ET_A receptor specific antibody confirmed increased receptor density following balloon injury. Thus, in an in vivo double balloon injury model for coronary artery restenosis, the response to vascular injury is increased tissue ET-1 content and upregulation of ET_A receptor density associated with increased receptor protein. Received: 1 March 1999, Returned for revision: 12 April 1999, Revision received: 11 May 1999, Accepted: 28 May 1999     

Rho激酶在小型猪白介素-1β介导的冠状动脉痉挛中的作用机制

目的探讨Rho激酶途径在冠状动脉痉挛发病中的作用机制。方法小型雄性家猪随机分为对照组(n=8)和模型组(n=8),冠状动脉外膜分别包裹吸附含生理盐水和白介素(IL)-1β琼脂糖微粒悬液的纸巾。2周后,采用冠状动脉造影观察管腔狭窄程度及5-羟色胺诱发冠状动脉痉挛情况。测定冠状动脉包裹血管段Rho激酶mRNA表达、肌球蛋白结合亚基磷酸化表达及光镜病理学改变。结果冠状动脉外膜包裹IL-1β血管段发生不同程度的管腔狭窄,5-羟色胺可诱发病变血管段痉挛。模型组与对照组相比,Rho激酶的mRNA表达病变血管段明显上调[(98·20±7·66)%对(63·70±4·26)%,P<0·05];肌球蛋白轻链磷酸酶的肌球蛋白结合亚基磷酸化表达升高(25485±4745对6510±779,P<0·05)。光镜可见病变血管段内膜增殖及炎症细胞聚集现象。结论Rho激酶参与IL-1β介导的冠状动脉痉挛的发生,其可能是通过增加肌球蛋白结合亚基磷酸化水平,抑制肌球蛋白轻链磷酸酶活性及加强钙增敏途径所致。     

Spontaneous coronary vasospasm in KATP mutant mice arises from a smooth muscle-extrinsic process

In the vasculature, ATP-sensitive potassium channels (KATP) channels regulate vascular tone. Mice with targeted gene disruptions of KATP subunits expressed in vascular smooth muscle develop spontaneous coronary vascular spasm and sudden death. From these models, it was hypothesized that the loss of KATP channel activity in arterial vascular smooth muscle was responsible for coronary artery spasm. We now tested this hypothesis using a transgenic strategy where the full-length sulfonylurea receptor containing exon 40 was expressed under the control of a smooth muscle-specific SM22alpha promoter. Two transgenic founder lines were generated and independently bred to sulfonylurea receptor 2 (SUR2) null mice to generate mice that restored expression of KATP channels in vascular smooth muscle. Transgenic expression of the sulfonylurea receptor in vascular smooth muscle cells was confirmed by detecting mRNA and protein from the transgene. Functional restoration was determined by recording pinacidil-based KATP current by whole cell voltage clamping of isolated aortic vascular smooth muscle cells isolated from the transgenic restored mice. Despite successful restoration of KATP channels in vascular smooth muscle, transgene-restored SUR2 null mice continued to display frequent episodes of spontaneous ST segment elevation, identical to the phenotype seen in SUR2 null mice. As in SUR2 null mice, ST segment elevation was frequently followed by atrioventricular heart block. ST segment elevation and coronary perfusion pressure in the restored mice did not differ significantly between transgene-negative and transgene-positive SUR2 null mice. We conclude that spontaneous coronary vasospasm and sudden death in SUR2 null mice arises from a coronary artery vascular smooth muscle-extrinsic process.     

Role of endothelin-1 in genesis of coronary artery disease

BACKGROUND: The endothelial cells produce the most potent vasoconstrictor known as endothelin-1. Elevated plasma levels of endothelin have been associated with coronary artery disease, essential hypertension and heart failure. The aims of the present study were, to compare the plasma endothelin-1 levels in coronary artery disease patients and healthy controls, to confirm endothelin-1 as surrogate marker for coronary artery disease and to compare the presence of endothelin-1 like immunoreactivity in aortic and internal mammary artery specimens obtained during coronary artery bypass graft surgery. METHODS AND RESULTS: The circulating levels of endothelin-1 were determined by enzyme-linked immunoassay in patients of coronary artery disease (n=145) and compared with healthy controls (n=70). Tissue endothelin-1 immunoreactivity was examined by immunohistochemical method in aortic and internal mammary artery tissue specimens obtained from 20 patients of coronary artery disease during coronary artery bypass grafting to understand the role of endothelin in atherosclerosis. Significantly higher levels (p < 0.001) of endothelin-1 were observed in all patients of coronary artery disease as compared to healthy controls. The immunoreactivity of endothelin-1 was localized to endothelial cell layer in internal mammary artery whereas in aortic specimens, in addition to endothelial cell layer, immunoreactivity was seen in the cytoplasm of smooth muscle cells of intima and media. CONCLUSIONS: The significant increase in plasma endothelin-1 in coronary artery disease cases as compared to healthy subjects and presence of tissue endothelin-1 immunoreactivity in smooth muscle cells of intimal as well as medial layers of aorta confirms the role of endothelin-1 as a surrogate marker of atherosclerosis.     

Functional and structural adaptations of coronary microvessels distal to a chronic coronary artery stenosis

Distal to a chronic coronary artery stenosis, structural remodeling of the microvasculature occurs. The microvascular functional changes distal to the stenosis have not been studied in detail. We tested the hypothesis that microvascular structural remodeling is accompanied by altered regulation of coronary vasomotor tone with increased responsiveness to endothelin-1. Vasomotor tone was studied in coronary microvessels from healthy control swine and from swine 3 to 4 months after implantation of an occluder that causes a progressive coronary narrowing, resulting in regional left ventricular dysfunction and blunted myocardial vasodilator reserve. Arterioles (approximately 200-microm passive inner diameter at 60 mm Hg) were isolated from regions perfused by the stenotic left anterior descending and normal left circumflex coronary arteries and studied in vitro. Passive pressure-diameter curves demonstrated reduced distensibility of subendocardial left anterior descending compared with subendocardial left circumflex or control arterioles, suggestive of structural remodeling. Myogenic responses were blunted in subendocardial left anterior descending compared with left circumflex arterioles, reflecting altered smooth muscle function. However, vasodilator responses to nitroprusside and bradykinin were not different in the endocardium, suggesting preserved endothelium and smooth muscle responsiveness. Finally, vasoconstrictor responses to endothelin-1 were enhanced in left anterior descending arterioles compared with left circumflex or control arterioles. Regional myocardial vascular conductance responses to bradykinin and endothelin in vivo confirmed the in vitro observations. In conclusion, inward remodeling of coronary microvessels distal to a stenosis is accompanied by exaggerated vasoconstrictor responses to endothelin-1. These structural and functional alterations may aggravate flow abnormalities distal to a chronic coronary artery stenosis.     

The mystery of coronary artery spasm

Coronary artery spasm is an important cause of chest pain and myocardial ischaemia. It can be defined as an exaggerated contractile response of epicardial coronary artery smooth muscle to various stimuli but the underlying mechanism is not well understood. Recent studies have shown that the loss of endothelial vasodilatory function in conjunction with an increase in vascular smooth muscle constrictor sensitivity to calcium are the likely predisposing conditions for coronary spasm. This review highlights current understanding of the pathophysiology, predisposing factors, diagnostic and therapeutic approaches for coronary spasm.     

The role of vascular failure in coronary artery spasm

Coronary artery spasm plays an important role in the pathogenesis of angina pectoris as well as acute coronary syndrome and sudden death. The prevalence of coronary spasm is greater in East Asian populations than in other parts of the world. Although the mechanism of coronary spasm is still unclear, both endothelial and smooth muscle dysfunction have been reported to play a role. We recently proposed a new concept termed 'vascular failure' that represents an integration of endothelial and smooth muscle abnormalities. Thus, vascular failure is the primary cause of coronary artery spasm.