Chiolero A, Maillard M, Nussberger J, Brunner H R, Burnier M
Division of Hypertension and Vascular Medicine, CHUV, and Policlinique médicale universitaire, Lausanne, Switzerland.
Hypertension. 2000 Oct;36(4):631-7. doi: 10.1161/01.hyp.36.4.631.
The purpose of this study was to evaluate the contribution of renal sodium handling by the proximal tubule as an independent determinant of blood pressure responsiveness to salt in hypertension. We measured blood pressure (BP), renal hemodynamics, and segmental renal sodium handling (with lithium used as a marker of proximal sodium reabsorption) in 38 hypertensive patients and 27 normotensive subjects (15 young and 12 age-matched) on a high and low sodium diet. In control subjects, changing the diet from a low to a high sodium content resulted in no change in BP and increases in glomerular filtration rate (P<0.05), renal plasma flow (P<0.05), and fractional excretion of lithium (FE(Li), P<0.01). In hypertensive patients, comparable variations of sodium intake induced an increase in BP with no change in renal hemodynamics and proximal sodium reabsorption. When analyzed by tertiles of their BP response to salt, salt-insensitive hypertensive patients of the first tertile disclosed a pattern of adaptation of proximal sodium reabsorption comparable to that of control subjects, whereas the most salt-sensitive patients of the third tertile had an inverse pattern with a high FE(Li) on low salt and a lower FE(Li) on high salt, suggesting an inappropriate modulation of proximal sodium reabsorption. The BP response to salt correlated positively with age (r=0.34, P=0.036) and negatively with the changes in FE(Li) (r=-0.37, P=0.029). In a multivariate analysis, the changes in FE(Li) were significantly and independently associated with the salt-induced changes in BP. These results suggest that proximal sodium reabsorption is an independent determinant of the BP response to salt in hypertension.
本研究的目的是评估近端小管对肾钠的处理作为高血压患者血压对盐反应性的独立决定因素的作用。我们在38例高血压患者和27例血压正常者（15例年轻人和12例年龄匹配者）中测量了血压（BP）、肾血流动力学和肾节段性钠处理（用锂作为近端钠重吸收的标志物），这些患者均采用高钠和低钠饮食。在对照组中，将饮食从低钠改为高钠会使血压无变化，但肾小球滤过率（P<0.05）、肾血浆流量（P<0.05）和锂排泄分数（FE(Li)，P<0.01）增加。在高血压患者中，钠摄入量的类似变化会导致血压升高，而肾血流动力学和近端钠重吸收无变化。当根据他们对盐的血压反应三分位数进行分析时，第一三分位数中对盐不敏感的高血压患者表现出与对照组相当的近端钠重吸收适应模式，而第三三分位数中对盐最敏感的患者则呈现相反模式，即低盐时FE(Li)高，高盐时FE(Li)低，提示近端钠重吸收调节不当。血压对盐的反应与年龄呈正相关（r=0.34，P=0.036），与FE(Li)的变化呈负相关（r=-0.37，P=0.029）。在多变量分析中，FE(Li)的变化与盐诱导的血压变化显著且独立相关。这些结果表明，近端钠重吸收是高血压患者血压对盐反应的独立决定因素。
