餐后血脂抑制甲状腺功能减退症患者的内皮依赖性血管舒张功能

Postprandial lipaemia suppresses endothelium-dependent arterial dilation in patients with hypothyroidism

目的探讨临床甲状腺功能减退症(简称甲减)和亚临床甲减患者餐后血脂与血管内皮功能的关系。方法选择10名正常女性受试者为对照组,20名甲减患者分成两组:临床甲减组与亚临床甲减组(每组各10例)。采用高分辨血管外超声法检测肱动脉血流介导的内皮依赖性血管舒张功能和硝酸甘油(GNT)介导的内皮非依赖性血管舒张功能。结果餐后血脂引起甲减患者血管内皮功能异常与三酰甘油和自由基水平密切相关。脂肪餐负荷试验中,甲减患者及正常对照组在餐后4 h时,内皮依赖性血管舒张功能降低(P<0.05),对照组和亚临床甲减组患者在8 h时内皮依赖性血管舒张功能恢复到基线水平,亚临床甲减组患者在6 h时内皮依赖性血管舒张功能低于基线水平(P<0.05)。然而,临床甲减组患者在进食脂负荷餐后6 h时内皮依赖性血管舒张功能继续下降(P<0.01),在8 h时开始升高,但仍低于基线水平(P<0.05)。Spearman’s分析显示甲减组(P<0.01)和对照组患者(P<0.05)进食脂负荷餐后内皮依赖性血管舒张功能与三酰甘油﹑硫代巴比土酸反应物质(TBARS)水平呈负相关,而三酰甘油水平与TBARS水平呈正相关。结论进食脂负荷餐后,甲减患者和正常对照组的内皮依赖性血管舒张功能降低,且与血清三酰甘油和氧自由基水平密切相关。

Objective To investigate the relationship between postprandial lipeamia（PPL） and endothelial dysfunction in patients with overt hypothyroidism（oHT） and subclinical hypothyroidism（sHT）.Methods Female subjects with oHT and sHT,as well as female healthy subjects with euthyroid state were enrolled（10 case each group）.The examination of brachial artery flow-mediated dilation（FMD） and GNT mediated endothelium-dependent dilation was performed by high resolution ultrasound.Results Endothelial dysfunction after postprandial lipaemia is related to the extent of hypertriglyceridemia,triglyceride and free radicals.FMD decreased significantly at 4h point in 3 groups,（P〈0.05） and then FMD in control and sHT restored to baseline at 8h point,it was lower than baseline in sHT group at 6-h point（P〈0.05）.However,FMD continue to decreased at 6h point（P〈0.01）,and then increased at 8h point,which was still lower than baseline（P〈0.05） in oHT.Spearman’s analysis showed a negative correlation between FMD and triglyceride,a negative correlation between FMD and TBARS and a positive correlation between triglyceride and TBARS levels during oral lipid-loading test in hypothyroid patients（P〈0.01） and controls（P〈0.05）.Conclusion In hypothyroid subjects,even in healthy individuals,FMD was impairment after an oral fat challenge.The endothelial dysfunction observed after an oral fat challenge is related to the extent of hypertriglyceridemia and oxygen-derived free radicals.