慢性盐负荷及补钾对血压盐敏感者血浆脂联素的影响

Effects of Chronic Salt Loading and Potassium Supplement on Plasma Adiponectin in Normotensive Salt-sensitive Adults

目的通过观察慢性盐负荷及补钾后血浆脂联素水平的变化及其与动脉血压的关系,探讨脂联素在血压盐敏感性发生发展中的作用及补钾的保护意义。方法选取30例年龄在16～60岁的血压正常者参与为期3周的慢性盐负荷及补钾干预试验,包括基线调查3d,低盐饮食、高盐饮食、高盐补钾饮食各7d。根据其平均动脉压(MAP)于高盐饮食期较低盐饮食期升高幅度≥10%为标准分为盐敏感组(n=10)和盐不敏感组(n=20),分别于基线及各干预期末抽取空腹静脉血标本。血浆脂联素用酶联免疫吸附法测定。结果盐敏感检出率为33%。盐负荷后,盐敏感组血浆脂联素的浓度有所下降,但差异无统计学意义,而盐不敏感组血浆脂联素的浓度明显升高[(7.3±3.9)比(5.8±2.2)mg/L,P<0.05];在高盐摄入的基础上大剂量口服补钾可以逆转高盐负荷对盐敏感组血浆脂联素浓度的影响[(8.2±1.1)比(6.2±0.7)mg/L,P<0.05]。盐敏感组盐负荷前后及补钾前后血浆脂联素变化幅度与MAP变化幅度均呈负相关(r=-0.639,r=-0.708,均P<0.05)。结论血压盐敏感者于高盐负荷后动脉血压升高,而血浆脂联素不升高;同时补充钾盐可以逆转盐负荷诱导的血压和脂联素变化。提示补钾除拮抗钠盐的升压作用外,可能通过升高脂联素水平而发挥调节血压和心血管保护作用。

Objective To investigate the effects of dietary sodium intake on plasma adiponectin （APN） in salt-sensitive normotensive adults and the protective the effects of dietary potassium supplement.Methods Thirty normotensive volunteers,aged from 16-60 years,were selected to undergo a low-sodium diet （51.3 mmol/d） for 7 days,a high-sodium diet （307.8 mmol/d） for 7 days,and then subsequently,a high-sodium plus potassium diet （60 mmol/d） for an additional 7 days.The volunteers were classified as salt sensitive （SS,10 subjects） or non-salt sensitive group （NSS,20 subjects） on the basis of their mean arterial blood pressure （MAP） increasement （more than 10 percent at the end of the high-sodium phase compared with the low-sodium phase）.Fasting blood samples were taken on the baseline and on the sixth day of each three intervention phases.Plasma APN concentration was measured using an enzyme-linked immunosorbent assay system.Results The prevalence of SS is 33%.After salt loading,no significant change was found in the plasma APN concentrations in SS group despite the decline,whereas plasma APN level increased significantly in NSS group [（7.3±3.9） vs （5.8±2.2）mg/L,P〈0.05].A high-sodium diet-induced alterations was abrogated by potassium supplementation in SS group [（8.2±1.1） vs （6.2±0.7）mg/L,P〈0.05].Further analyses showed that in SS volunteers,there were significantly negative correlations between the change argumentation of MAP and plasma APN after a high-sodium diet （r=-0.639,P〈0.05） and a high-sodium plus potassium diet （r=-0.708,P〈0.05）.Conclusion Salt loading induced high blood pressure in normotensive salt-sensitive adults,while plasma APN did not rise,and dietary potassium supplementation could reverse these alterations.It suggests that potassium supplementation possibly acts through increasing the level of APN to play the role of blood pressure regulation and cardiovascular protection.