McSorley P T, Young I S, Bell P M, Fee J P H, McCance D R
Department of Anaesthesia, Altnagelvin Area Hospital, Londonderry, Northern Ireland, UK.
Climacteric. 2003 Sep;6(3):238-47.
Estrogen deficiency is associated with increased cardiovascular risk and endothelial dysfunction. Improvements in endothelial function with antioxidants, including vitamin C, have been reported. We aimed to determine the acute effect of vitamin C on endothelial function in healthy women with established menopause.
Subjects (aged 47-59 years) were at least 1 year postmenopause. Ten (serum estradiol < 50 pmol/l) were not receiving hormone replacement therapy, while eight hysterectomized subjects received subcutaneous estradiol.
Forearm blood flow (FBF; strain-gauge plethysmography) responses to intrabrachial artery infusions of incremental doses of acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation) were determined at baseline, and following 1.5 g vitamin C given intravenously.
At baseline, estrogen-treated subjects had a lower index of insulin resistance (homeostasis model assessment, HOMA) and lower fibrinogen than those of estrogen deficient subjects. There was a trend towards higher baseline FBF and larger baseline FBF response to acetylcholine in estrogen-treated subjects. FBF responses to acetylcholine were significantly enhanced after vitamin C in estrogen-deficient subjects (area under the dose-response curve (AUC): estrogen-deficient 9.9 +/- 2.6 vs. 15.1 +/- 3.2 (mean +/- SEM), p = 0.02; estrogen-treated 17.0 +/- 2.9 vs. 21.0 +/- 3.2, p = 0.07). Resting FBF and response to sodium nitroprusside were unchanged in either group by vitamin C. Plasminogen activator inhibitor-1 levels fell after vitamin C in the estrogen-deficient group (17.0 +/- 1.6 vs. 14.7 +/- 0.9 IU/ml, p = 0.03).
These results indicate that endothelial function may be improved acutely by antioxidant treatment in postmenopausal women with established estrogen deficiency.
雌激素缺乏与心血管风险增加及内皮功能障碍有关。据报道，包括维生素C在内的抗氧化剂可改善内皮功能。我们旨在确定维生素C对已绝经健康女性内皮功能的急性影响。
受试者（年龄47 - 59岁）绝经至少1年。10名（血清雌二醇<50 pmol/l）未接受激素替代治疗，而8名接受子宫切除的受试者接受皮下雌二醇治疗。
在基线时以及静脉给予1.5 g维生素C后，测定前臂血流量（FBF；应变片体积描记法）对肱动脉内递增剂量乙酰胆碱（内皮依赖性血管舒张）和硝普钠（非内皮依赖性血管舒张）输注的反应。
在基线时，接受雌激素治疗的受试者的胰岛素抵抗指数（稳态模型评估，HOMA）和纤维蛋白原水平低于雌激素缺乏的受试者。接受雌激素治疗的受试者的基线FBF和对乙酰胆碱的基线FBF反应有升高趋势。雌激素缺乏的受试者在给予维生素C后，对乙酰胆碱的FBF反应显著增强（剂量反应曲线下面积（AUC）：雌激素缺乏组9.9±2.6对15.1±3.2（平均值±标准误），p = 0.02；接受雌激素治疗组17.0±2.9对21.0±3.2，p = 0.07）。两组中，维生素C均未改变静息FBF及对硝普钠的反应。雌激素缺乏组给予维生素C后纤溶酶原激活物抑制剂-1水平下降（17.0±1.6对14.7±0.9 IU/ml，p = 0.03）。
这些结果表明，抗氧化剂治疗可使已确诊雌激素缺乏的绝经后女性的内皮功能得到急性改善。
