Insulin resistance and endothelial dysfunction in smokers: effects of vitamin C
Insulin resistance and endothelial dysfunction in smokers: effects of vitamin C
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DOI：
10.1152/ajpheart.2000.279.3.h1172
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发表时间：
2000-09-01
影响因子：
4.8
通讯作者：
Yasue, H
中科院分区：
文献类型：
--
作者：
Hirai, N;Kawano, H;Yasue, H
吸烟损害内皮功能，是动脉粥样硬化和冠心病的主要危险因素之一。胰岛素抵抗与动脉粥样硬化的主要危险因素有关。我们通过测量稳态血糖（SSPG）和肱动脉血流介导的舒张（FMD）来研究维生素C对胰岛素敏感性和内皮功能的影响。我们研究了16名糖耐量正常的吸烟者，15名糖耐量受损（IGT）的非吸烟者和17名糖耐量正常的非吸烟者作为对照。与对照组相比，吸烟者和非吸烟者IGT患者的SSPG和FMD均变钝。在吸烟者中，维生素C降低了SSPG（方差分析P < 0.01），降低了血浆硫代巴比妥酸反应物质（TBARS）（方差分析P < 0.05），改善了FMD（方差分析P <0.05）。此外，维生素C改善了非吸烟IGT患者的SSPG（ANOVA，P < 0.005）和FMD（ANOVA，P <0.05）。对照组的SSPG、FMD或TBARS在输注维生素C后没有变化。吸烟者和非吸烟者IGT患者SSPG与FMD之间存在显著相关性，而对照组中未观察到相关性。总之，吸烟者和非吸烟者IGT患者的胰岛素敏感性和内皮功能均受损，维生素C可改善这一点。因此，活性氧增加在吸烟者和非吸烟者IGT的胰岛素抵抗以及内皮功能障碍的发病机制中起重要作用。
Cigarette smoking impairs endothelial function and is one of the major risk factors for atherosclerosis and coronary heart disease. Insulin resistance is associated with major risk factors for atherosclerosis. We examined the effects of vitamin C on insulin sensitivity and endothelial function by measuring steady-state plasma glucose (SSPG) and flow-mediated dilation (FMD) of the brachial artery. We studied 16 current smokers with normal glucose tolerance, 15 nonsmokers with impaired glucose tolerance (IGT), and 17 nonsmokers with normal glucose tolerance as controls. Both SSPG and FMD were blunted in smokers and nonsmokers with IGT compared with controls. In smokers, vitamin C decreased SSPG (P < 0.01 by ANOVA) with decreasing plasma thiobarbituric acid-reactive substances (TBARS) (P < 0.05 by ANOVA) and improved FMD (P, 0.05 by ANOVA). Furthermore, vitamin C improved both SSPG (P < 0.005 by ANOVA) and FMD (P, 0.05 by ANOVA) in nonsmokers with IGT. SSPG, FMD, or TBARS in controls did not change after vitamin C infusion. There was a significant correlation between SSPG and FMD both in smokers and nonsmokers with IGT, whereas no correlation was observed in controls. In conclusion, both insulin sensitivity and endothelial function were impaired in smokers and nonsmokers with IGT and were improved by vitamin C. Thus increased reactive oxygen species play an important role in the pathogenesis of insulin resistance as well as endothelial dysfunction in smokers and nonsmokers with IGT.