血压盐敏感者内皮功能损伤及补钾的保护作用研究

Endothelial function evaluation in salt-sensitive normaltensive and mild hypertensive subjects and effects of potassium supplement

目的通过观察血、尿-氧化氮（NO）水平的变化，探讨盐敏感者血管内皮功能损伤及补钾的保护作用。方法选39例年龄16～60岁、血压正常或血压轻度偏高者参与为期3周的慢性盐负荷及补钾试验，包括基线3天，低盐饮食、高盐饮食和高盐加补钾饮食各7天的研究。各个阶段测量体重、血压，并收集血、尿标本。结果盐敏感者血浆NO浓度和尿中NO水平在基线、低盐和高盐阶段均低于盐不敏感者；限盐后血、尿NO浓度增加，而高盐饮食后NO浓度显著减少；盐敏感者在高盐摄入的基础上大剂量口服补钾后血浆NO浓度、尿NO水平显著升高。结论盐敏感者尽管尚处在血压正常或血压轻度偏高阶段已存在一定程度的内皮功能损伤，且这种损伤与盐负荷相关联；大剂量补钾可能通过增加NO水平而改善盐敏感者的血管内皮功能。

Objective Salt-sensitivity plays an important role in essential hypertension and is associated with more severe target organ injury and higher mortality in patients with essential hypertension. However, the pathologic mechanism of salt-sensitivity is poorly understood and endothelial dysfunction might be involved in salt-sensitive hypertension. We, therefore, observed the endothelial function changes by measuring plasma and urine nitric oxide（NO） concentrations in salt-sensitive （SS） normaltensive and mild hypertensive subjects underwent various salt loading protocols and the effects of potassium supplement. Methods Thirty-nine normaltensive and mild hypertensive subjects （ 〈 160/100 mm Hg）, aged 16 -60, were enrolled and the study protocol is as follows： 3 days baseline investigation, 1 week lowsalt loading （3 g/day）, 1 week. high-salt loading （ 18 g/day） and 1 week high-salt loading plus potassium chloride （ 4. 5 g/day）. Results Plasma and urine NO levels were significantly lower in SS （n =8） subjects at baseline, low-salt and high-salt loading phases compared with salt-resistant subjects （ SR, n = 31 ） and oral potassium supplement to SS subjects with high salt loading significantly increased plasma and urine NO levels. Conclusion Endothelial function is impaired in normaltensive and mild hypertensive SS subjects. Oral potassium supplement could improve endothelial function in normaltensive and mild hypertensive SS subjects.