维生素C对高脂餐后内皮依赖性血管舒张功能的保护作用

目的探讨维生素C对高脂餐后内皮依赖性血管舒张功能变化的影响。方法74例冠心病患者被随机分为两组，分别在禁食12h后进食高脂餐与维生素C2g（A组，n＝37）或单纯的高脂餐（B组，n＝37）。分别采集餐前及餐后2、4、5、7h静脉血标本，用以测定血清甘油三酯(TG)、总胆固醇、低密度脂蛋白-胆固醇（LDL-C）、高密度脂蛋白-胆固醇（HDL-C）浓度。采用高分辨血管外超声法检测餐前及餐后4h肱动脉血流介导的内皮依赖性血管舒张功能和硝酸甘油介导的内皮非依赖性血管舒张功能。结果冠心病患者空腹状态的内皮依赖性血管舒张功能显著受损。服用维生素C2g（A组）餐后4h内皮依赖性血管舒张功能较餐前无显著变化［（3.63±0.59）%∶（4.51±0.49）%，P=0.064］；未服用维生素C2g（B组）餐后4h内皮依赖性血管舒张功能较餐前相比严重受损［（3.58±0.63）%∶（0.58±0.40）%，P<0.001］。高脂餐后硝酸甘油介导的内皮非依赖性血管舒张功能的变化无统计学意义［A组（19.48±1.38）%∶（20.25±1.21）%，P=0.498；B组（18.71±1.53）%∶（16.36±1.53）%，P=0.135］。两组受试者餐后2～7h血清TG浓度均显著升高。经相关分析结果显示B组受试者的餐后2h血清TG浓度增高值与餐后4h内皮依赖性血管舒张功能下降值显著正相关（r=0.395，P<0.02）。结论高脂餐后内皮依赖性血管舒张功能显著受损，大剂量维生素C对其有保护作用。

Effect of vitamin C on endothelium-dependent vasodilation in patients with coronary heart disease after a high-fat meal

Objective　To evaluate the effect of a single oral dose of vitamin C on postprandially impaired endothelium-dependent vasodilatation in patients with coronary heart disease (CHD) after a single high-fat meal. Methods　Seventy-four patients with CHD were randomly divided into two groups. Patients in group A (n=37) accepted 2 grams of vitamin C, whereas in group B (n=37) did not treated with vitamin C after a high-fat meal. The serum levels of triglyceride, total cholesterol, low density lipoprotein-cholesterol and high density lipoprotein-cholesterol in fasting and at 2, 4, 5, 7 hours after the high-fat meal were measured. Endothelium-dependent vasodilatation （flow-mediated vasodilatation） and endothelium-independent vasodilatation （nitroglycerin-induced vasodilatation）was assessed in the brachial artery by high-resolution ultrasound technique before eating and at 4 hours postprandially. Results　The fasting endothelium-dependent vasodilatations were impaired in CHD patients. The postprandial serum triglyceride concentration increased significantly at 2－7 hours after the high-fat meal in all subjects. The impaired endothelium-dependent vasodilatation restored ［（3.63±0.59）% vs （4.51±0.49）%，P=0.064］ in Group A, but significantly aggravated ［（3.58±0.63）% vs （0.58±0.40）%，P＜0.001］ in Group B. The postprandial endothelium-independent vasodilatation has no obvious change in the two groups compared with that in the fasting state ［Group A：（19.48±1.38）% vs（20.25±1.21）%，P=0.498；Group B：（18.71±1.53）% vs（16.36±1.53）%，P=0.135］. The decrement of postprandial flow-mediated vasodilatation positively correlated with the increment of 2-hour serum TG concentration (r=0.395, P＜0.02). Conclusion　The impaired endothelium-dependent vasodilatation aggravated in CHD patients after a high-fat meal, and vitamin C treatment has a promising benefit to CHD patients.