Sodium Pump Inhibitors In Blood Pressure Regulation

我们研究了在中度升高的收缩压(SBP：139+/-2；DBP：83+/-2毫米汞柱)的中老年人(8男3女；60+/-2岁)中，饮食盐限制的效果。我们测量了尿和血浆MBG水平、SBP、aPWV(随机、安慰剂对照、交叉设计)。我们还探讨了在低盐饮食(LS；77+/-9 mmol/天)和正常盐饮食(NS；144+/-7 mmol/天)5周条件下，MBG排泄量与SBP和aPWV的关系。氧化应激的标记物也被评估。 在5周低钠饮食与5周正常钠饮食(随机、交叉设计)后，SBP(127+/-3 mm Hg比138+/-5 mm Hg；P&lt；0.05)和aPWV(700+/-40 cm/s比843+/-36 cm/s，降低17%，P&lt；0.05)降低。在LS和NS条件下，每周尿MBG排泄量(25.4+/-1.8vs.30.7+/-2.1pmol/kg/day，p&lt；0.05)较低，并且在10周内与SBP(r=0.39，p&lt；0.001)和钠排泄量(r=0.46，p&lt；0.001)呈正相关。这些关系在NS期间持续存在，但不在LS条件下(p&lt；0.005)。MBG排泄量与aPWV呈正相关(r=0.51，p&lt；0.05)，与内皮细胞氧化酶NAD(P)H氧化酶-p47Phox的表达呈正相关(r=0.53，p&lt；0.05)。 综上所述，目前的结果表明，饮食钠限制减少了中度收缩压升高的中老年人肾脏MBG的排泄。我们的研究结果表明，MBG的这种降低可能通过减少氧化应激而导致大弹性动脉僵硬和SBP的降低，并伴随着饮食中钠的减少。鉴于动脉僵硬、SBP和盐敏感性的年龄相关性增加，这些结果呼应了最近美国人饮食中减少钠摄入量的呼吁，特别是在快速增长的中老年高危人群中。 这些结果首次在人类中表明，饮食盐限制减少了MBG的排泄，这与SBP和aPWV的降低以及血管弹性的改善有关。此外，在典型的美国饮食中，MBG与钠摄入期间的SBP呈正相关，这与现有证据在啮齿类动物/实验中喂食高钠饮食的人类中的证据相一致。

We studied the effect of dietary NaCl restriction performed in middle-aged/older adults (8 men and 3 women; 60+/-2 yrs) with moderately elevated systolic BP (SBP: 139+/-2; DBP: 83+/-2 mmHg). We measured urinary and plasma MBG levels, SBP, aPWV (randomized, placebo-controlled, cross-over design). We also explored the associations of MBG excretion with SBP and aPWV across conditions of 5 weeks of a low NaCl (LS; 77+/-9 mmol/day) and 5 weeks of a normal NaCl (NS; 144+/-7 mmol/day) diet. Markers of oxidative stress were also assessed. SBP (127+/-3 mmHg vs. 138+/- 5 mmHg; P<0.05) and aPWV (700+/-40 cm/sec vs. 843 +/- 36 cm/sec, 17% of reduction, P<0.05) were reduced following a 5-week low sodium vs. 5-week normal sodium diet (randomized, cross-over design). Urinary MBG excretion (weekly measurements) was lower during the LS vs. NS condition (25.4+/-1.8 vs. 30.7+/-2.1 pmol/kg/day, p<0.05) and was positively correlated with SBP (r=0.39, p<0.001) and sodium excretion (r = 0.46, p<0.001) across the 10 weeks. These relations persisted during the NS but not the LS condition (p<0.005). MBG excretion also was positively related to aPWV (r=0.51, p<0.05) and endothelial cell expression of the oxidant enzyme NAD(P)H oxidase-p47phox (r=0.53, p<0.05). In summary, the present results demonstrate that dietary sodium restriction reduces renal MBG excretion in middle-aged and older adults with moderately elevated systolic blood pressure. Our findings suggest that this reduction in MBG may contribute, possibly via reduced oxidative stress, to the reductions in large elastic artery stiffness and SBP that accompanied dietary sodium reduction. Given age-associated increases in arterial stiffness, SBP and salt sensitivity, these results echo recent calls for reduced sodium intake in the American diet, particularly in the rapidly growing, at-risk population of middle-aged and older adults. These results show, for the first time in humans, that dietary salt restriction reduces MBG excretion, and this is associated with reductions in SBP and aPWV, and with improved elasticity of blood vessels. In addition, MBG is positively related to SBP during sodium intake typical of an American diet, complimenting existing evidence in rodents/humans fed experimentally high sodium diets.