Cominacini Luciano, Fratta Pasini Anna, Garbin Ulisse, Nava Cristina, Davoli Anna, Criscuoli Marco, Crea Attilio, Sawamura Tatsuya, Lo Cascio Vincenzo
Department of Biomedical and Surgical Sciences, Medicina D, University of Verona, Verona, Italy.
J Am Coll Cardiol. 2003 Nov 19;42(10):1838-44. doi: 10.1016/j.jacc.2003.06.011.
The objective of the present study was to elucidate the vasodilator mechanisms of nebivolol, a high selective beta(1)-receptor antagonist with antioxidant properties.
Oxidative inactivation of nitric oxide (NO) is regarded as an important cause of its decreased biological activity.
Oxidative stress was induced through the binding of oxidized (ox)-low-density lipoprotein (LDL) to its specific endothelial receptor, called "lectin-like oxidized LDL receptor-1" (LOX-1), in bovine and human endothelial cells and in Chinese hamster ovary cells stably expressing bovine LOX-1 (BLOX-1-CHO cells). Reactive oxygen species (ROS), superoxide (O(2)(*-)), and NO were measured in cells by flow cytometry.
Nebivolol and its 4-keto derivative prevented in a dose-dependent manner the increase of ROS (p < 0.001) and O(2)(*-) (p < 0.001) in bovine aortic endothelial cells (BAECs), human umbilical vein endothelial cells (HUVECs), and BLOX-1-CHO cells stimulated with ox-LDL. Atenolol had no effect. The incubation of HUVECs and BAECs with ox-LDL reduced basal and bradykinin-induced NO and nitrite concentration (p from <0.001 to <0.01). Nebivolol and its 4-keto derivative prevented the reduction of basal and stimulated NO and nitrite concentration (p from <0.001 to <0.01) while atenolol had no effect. The preincubation of BAECs with blocking anti-LOX-1 monoclonal antibody (LOX-1 mAb) significantly counteracted the effect of ox-LDL on stimulated generation of NO (p < 0.001), but the effect was significantly lower than that of nebivolol and its 4-keto derivative alone (p < 0.01).
In conclusion, the findings of the present study indicate that nebivolol increases NO also by decreasing its oxidative inactivation.
本研究的目的是阐明奈必洛尔（一种具有抗氧化特性的高选择性β₁受体拮抗剂）的血管舒张机制。
一氧化氮（NO）的氧化失活被认为是其生物活性降低的重要原因。
通过氧化型（ox）-低密度脂蛋白（LDL）与其特异性内皮受体“凝集素样氧化型LDL受体-1”（LOX-1）结合，在牛和人内皮细胞以及稳定表达牛LOX-1的中国仓鼠卵巢细胞（BLOX-1-CHO细胞）中诱导氧化应激。通过流式细胞术测量细胞中的活性氧（ROS）、超氧阴离子（O₂⁻*）和NO。
奈必洛尔及其4-酮衍生物以剂量依赖性方式阻止了牛主动脉内皮细胞（BAECs）、人脐静脉内皮细胞（HUVECs）和用ox-LDL刺激的BLOX-1-CHO细胞中ROS（p < 0.001）和O₂⁻*（p < 0.001）的增加。阿替洛尔无此作用。用ox-LDL孵育HUVECs和BAECs会降低基础和缓激肽诱导的NO及亚硝酸盐浓度（p从<0.001至<0.01）。奈必洛尔及其4-酮衍生物可防止基础和刺激后的NO及亚硝酸盐浓度降低（p从<0.001至<0.01），而阿替洛尔无此作用。用阻断性抗LOX-1单克隆抗体（LOX-1 mAb）预孵育BAECs可显著抵消ox-LDL对刺激产生NO的作用（p < 0.001），但该作用明显低于单独使用奈必洛尔及其4-酮衍生物的作用（p < 0.01）。
总之，本研究结果表明奈必洛尔还通过减少NO的氧化失活来增加NO。
