Thengchaisri Naris, Hein Travis W, Ren Yi, Kuo Lih
Department of Medical Physiology, Cardiovascular Research Institute, College of Medicine, Texas A&M Health Science Center, Temple, TX 76504, USA; Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand.
Department of Surgery, College of Medicine, Texas A&M Health Science Center, Temple, TX 76504, USA.
J Mol Cell Cardiol. 2015 Sep;86:75-84. doi: 10.1016/j.yjmcc.2015.07.014. Epub 2015 Jul 23.
Elevated levels of endothelin-1 (ET-1), a potent vasoactive peptide, are implicated as a risk factor for cardiovascular diseases by exerting vasoconstriction. The aim of this study was to address whether ET-1, at sub-vasomotor concentrations, elicits adverse effects on coronary microvascular function. Porcine coronary arterioles (50-100μm) were isolated, cannulated and pressurized without flow for in vitro study. Diameter changes were recorded using a videomicrometer. Arterioles developed basal tone (60±3μm) and dilated to the endothelium-dependent nitric oxide (NO)-mediated vasodilators serotonin (1nmol/L to 0.1μmol/L) and adenosine (1nmol/L to 10μmol/L). Treating the vessels with a clinically relevant sub-vasomotor concentration of ET-1 (10pmol/L, 60min) significantly attenuated arteriolar dilations to adenosine and serotonin but not to endothelium-independent vasodilator sodium nitroprusside. The arteriolar wall contains ETA receptors and the adverse effect of ET-1 was prevented by ETA receptor antagonist BQ123, the superoxide scavenger Tempol, the NADPH oxidase inhibitors apocynin and VAS2870, the NOX2-based NADPH oxidase inhibitor gp91 ds-tat, or the p38 kinase inhibitor SB203580. However, ETB receptor antagonist BQ788, H2O2 scavenger catalase, scrambled gp91 ds-tat, or inhibitors of xanthine oxidase (allopurinol), PKC (Gö 6983), Rho kinase (Y27632), and c-Jun N-terminal kinase (SP600125) did not protect the vessel. Immunohistochemical staining showed that ET-1 elicited Tempol-, apocynin- and SB203580-sensitive superoxide productions in the arteriolar wall. Our results indicate that exposure of coronary arterioles to a pathophysiological, sub-vasomotor concentration of ET-1 leads to vascular dysfunction by impairing endothelium-dependent NO-mediated dilation via p38 kinase-mediated production of superoxide from NADPH oxidase following ETA receptor activation.
内皮素 -1（ET-1）是一种强效血管活性肽，其水平升高通过引起血管收缩而被认为是心血管疾病的一个危险因素。本研究的目的是探讨在低于血管运动浓度的情况下，ET-1是否会对冠状动脉微血管功能产生不良影响。分离猪的冠状动脉小动脉（50 - 100μm），插管并在无血流的情况下加压进行体外研究。使用视频显微镜记录直径变化。小动脉产生基础张力（60±3μm），并对内皮依赖性一氧化氮（NO）介导的血管舒张剂血清素（1nmol/L至0.1μmol/L）和腺苷（1nmol/L至10μmol/L）产生舒张反应。用临床相关的低于血管运动浓度的ET-1（10pmol/L，60分钟）处理血管，可显著减弱小动脉对腺苷和血清素的舒张反应，但对非内皮依赖性血管舒张剂硝普钠无此影响。小动脉壁含有ETA受体，ETA受体拮抗剂BQ123、超氧化物清除剂Tempol、NADPH氧化酶抑制剂阿扑辛和VAS2870、基于NOX2的NADPH氧化酶抑制剂gp91 ds - tat或p38激酶抑制剂SB203580可预防ET-1的不良影响。然而，ETB受体拮抗剂BQ788、H₂O₂清除剂过氧化氢酶、乱序的gp91 ds - tat或黄嘌呤氧化酶抑制剂（别嘌呤醇）、蛋白激酶C抑制剂（Gö 6983）、Rho激酶抑制剂（Y27632）和c - Jun N末端激酶抑制剂（SP600125）不能保护血管。免疫组织化学染色显示，ET-1在小动脉壁中引发了对Tempol、阿扑辛和SB203580敏感的超氧化物生成。我们的结果表明，冠状动脉小动脉暴露于病理生理状态下低于血管运动浓度的ET-1会导致血管功能障碍，这是通过ETA受体激活后，p38激酶介导NADPH氧化酶产生超氧化物，从而损害内皮依赖性NO介导的舒张作用。
