Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA.
Department of Kinesiology, West Chester University, West Chester, PA, USA.
Eur J Appl Physiol. 2020 Jun;120(6):1383-1389. doi: 10.1007/s00421-020-04370-0. Epub 2020 Apr 18.
Low-flow mediated constriction (L-FMC) has emerged as a valuable and complementary measure of flow-mediated dilation (FMD) for assessing endothelial function non-invasively. High dietary sodium has been shown to impair FMD independent of changes in blood pressure (BP), but its effects on L-FMC are unknown.
To test the hypothesis that high dietary sodium would attenuate brachial artery L-FMC in salt-resistant adults.
Fifteen healthy, normotensive adults (29 ± 6 years) participated in a controlled feeding study. Following a run-in diet, participants completed a 7-day low sodium (LS; 20 mmol sodium/day) and 7-day high sodium (HS; 300 mmol sodium/day) diet in randomized order. On the last day of each diet, 24 h urine was collected and assessments of 24 h ambulatory BP and L-FMC were performed. Salt-resistance was defined as a change in 24 h ambulatory mean arterial pressure (MAP) between the LS and HS diets of ≤ 5 mmHg. Resting vascular tone and L-FMC were calculated from ultrasound-derived arterial diameters.
High dietary sodium increased serum sodium and urinary sodium excretion (p < 0.001 for both), but 24 h MAP was unchanged (p = 0.16) by design. High dietary sodium augmented vascular tone (LS: 91 ± 23%, HS: 125 ± 56%, p = 0.01) and attenuated L-FMC (LS: - 0.58 ± 0.99%, HS: 0.17 ± 1.23%, p = 0.008).
These findings in salt-resistant adults provide additional evidence that dietary sodium has adverse vascular effects independent of changes in BP.
低流量介导的收缩（L-FMC）已成为一种有价值的、补充性的血流介导扩张（FMD）测量方法，可用于非侵入性评估内皮功能。已有研究表明，高膳食钠可独立于血压（BP）变化而损害 FMD，但它对 L-FMC 的影响尚不清楚。
检验高膳食钠会减弱盐抵抗成年人肱动脉 L-FMC 的假设。
15 名健康、血压正常的成年人（29±6 岁）参与了一项对照喂养研究。在进行了一个适应期饮食后，参与者按照随机顺序完成了 7 天的低钠（LS；20mmol 钠/天）和 7 天的高钠（HS；300mmol 钠/天）饮食。在每个饮食的最后一天，收集 24 小时尿液，并进行 24 小时动态血压和 L-FMC 评估。盐抵抗定义为 LS 和 HS 饮食之间 24 小时动态平均动脉压（MAP）的变化≤5mmHg。通过超声测量动脉直径来计算静息血管张力和 L-FMC。
高膳食钠增加了血清钠和尿钠排泄（均 p<0.001），但 24 小时 MAP 不变（p=0.16）。高膳食钠增加了血管张力（LS：91±23%，HS：125±56%，p=0.01）并减弱了 L-FMC（LS：-0.58±0.99%，HS：0.17±1.23%，p=0.008）。
这些在盐抵抗成年人中的发现提供了更多证据，表明膳食钠对血管有不良影响，独立于 BP 变化。
