Hink Ulrich, Oelze Matthias, Kolb Philip, Bachschmid Markus, Zou Ming-Hui, Daiber Andreas, Mollnau Hanke, August Michael, Baldus Stefan, Tsilimingas Nikos, Walter Ulrich, Ullrich Volker, Münzel Thomas
University Hospital Eppendorf, Division of Cardiology, Hamburg, Germany.
J Am Coll Cardiol. 2003 Nov 19;42(10):1826-34. doi: 10.1016/j.jacc.2003.07.009.
We tested whether in vivo nitroglycerin (NTG) treatment causes tyrosine nitration of prostacyclin synthase (PGI(2)-S), one of the nitration targets of peroxynitrite, and whether this may contribute to nitrate tolerance.
Long-term NTG therapy causes tolerance secondary to increased vasoconstrictor sensitivity and increased vascular formation of reactive oxygen species. Because NTG releases nitric oxide (NO), NTG-induced stimulation of superoxide production should increase vascular nitrotyrosine levels, compatible with increased formation of peroxynitrite, the reaction product from NO and superoxide.
New Zealand White rabbits and Wistar rats were treated with NTG (0.4 mg/h for 3 days). Tolerance was assessed with isometric tension studies. Vascular peroxynitrite levels were quantified with luminol-derived chemiluminescence (LDCL) and peroxynitrite scavengers, such as uric acid and ebselen. As a surrogate parameter for the assessment of the activity of cyclic guanosine monophosphate-dependent kinase-I (cGK-I; the final signaling pathway for NO), the phosphorylation of the vasodilator-stimulated phosphoprotein (P-VASP) at serine 239 was analyzed.
Nitroglycerin treatment increased LDCL, and the inhibitory effect of uric acid and ebselen on LDCL was augmented in tolerant rings. Immunoprecipitation of 3-nitrotyrosine-containing proteins and immunohistochemistry analysis identified PGI(2)-S as a tyrosine-nitrated protein. Accordingly, conversion of ((14)C)-PGH(2) into 6-keto-PGF(1 alpha) (=PGI(2)-S activity) was strongly inhibited. In vitro incubation of tolerant rings with ebselen and uric acid markedly increased the depressed P-VASP levels and improved NTG sensitivity of the tolerant vasculature.
Nitroglycerin-induced vascular peroxynitrite formation inhibits the activity of PGI(2)-S as well as NO, cGMP, and cGK-I signaling, which may contribute to vascular dysfunction in the setting of tolerance.
我们检测了体内硝酸甘油（NTG）治疗是否会导致前列环素合酶（PGI₂-S）发生酪氨酸硝化，PGI₂-S是过氧亚硝酸盐的硝化靶点之一，以及这是否可能导致硝酸盐耐受性。
长期NTG治疗会导致耐受性，继发于血管收缩剂敏感性增加和活性氧在血管中的生成增加。由于NTG释放一氧化氮（NO），NTG诱导的超氧化物生成刺激应会增加血管硝基酪氨酸水平，这与过氧亚硝酸盐（NO和超氧化物的反应产物）生成增加相一致。
用NTG（0.4mg/h，持续3天）治疗新西兰白兔和Wistar大鼠。通过等长张力研究评估耐受性。用鲁米诺衍生的化学发光法（LDCL）和过氧亚硝酸盐清除剂（如尿酸和依布硒仑）对血管过氧亚硝酸盐水平进行定量。作为评估环磷酸鸟苷依赖性激酶-I（cGK-I；NO的最终信号通路）活性的替代参数，分析了血管舒张刺激磷蛋白（P-VASP）在丝氨酸239处的磷酸化情况。
硝酸甘油治疗增加了LDCL，并且尿酸和依布硒仑对LDCL的抑制作用在耐受性血管环中增强。对含3-硝基酪氨酸的蛋白质进行免疫沉淀和免疫组织化学分析确定PGI₂-S是一种酪氨酸硝化的蛋白质。因此，（¹⁴C）-PGH₂转化为6-酮-PGF₁α（=PGI₂-S活性）受到强烈抑制。用依布硒仑和尿酸对耐受性血管环进行体外孵育可显著提高降低的P-VASP水平，并改善耐受性血管系统对NTG的敏感性。
硝酸甘油诱导的血管过氧亚硝酸盐形成抑制了PGI₂-S的活性以及NO、cGMP和cGK-I信号传导，这可能导致耐受性情况下的血管功能障碍。
