Variability of urinary salt excretion estimated by spot urine in treated hypertensive patients

Renal Sodium Handling in Relation to Environmental and Genetic Factors in Untreated Chinese

BACKGROUND

We investigated proximal and distal renal tubular sodium handling, as assessed by fractional excretion of lithium (FELi) and fractional distal reabsorption rate of sodium (FDRNa), in relation to environmental and genetic factors in untreated patients.

METHODS

Our study participants were suspected hypertensive patients being off antihypertensive medication for ≥2 weeks and referred for 24-hour ambulatory blood pressure monitoring. We collected serum and 24-hour urine for measurement of sodium, creatinine, and lithium concentration, and calculated FELi and FDRNa. We genotyped 19 single-nucleotide polymorphisms associated with renal sodium handling or blood pressure using the ABI SNapShot method.

RESULTS

The 1,409 participants (664 men, 47.1%) had a mean (±SD) age of 51.0 ± 10.5 years. After adjustment for host factors, both FELi and FDRNa were significantly (P ≤ 0.01) associated with season and humidity, explaining ~1.3% and ~3.5% of the variance, respectively. FELi was highest in autumn and lowest in summer and intermediate in spring and winter (P = 0.007). FDRNa was also highest in autumn but lowest in winter and intermediate in spring and summer (P < 0.001). Neither FELi nor FDRNa was associated with outdoor temperature or atmospheric pressure (P ≥ 0.13). After adjustment for host and environmental factors and Bonferroni multiple testing, among the 19 studied genetic variants, only rs12513375 was significantly associated with FELi and FDRNa (P ≤ 0.004) and explained about 1.7% of the variance.

CONCLUSIONS

Renal sodium handling as measured by endogenous lithium clearance was sensitive to major environmental and genetic factors. Our finding is toward the use of these indexes for the definition of renal tubular dysfunction.

Biochemical interaction of salt sensitivity: a key player for the development of essential hypertension

Worldwide, more than 1 billion people have elevated blood pressure, with up to 45% of adults affected by the disease. In 2016 the global health study report on patients from 67 countries was released in Lancet, which identified hypertension as the world's leading cause for death and disability-adjusted years since 1990. This paper aims to analyze the pathophysiological connection between hemodynamic inflammatory reactions through sodium balance, salt sensitivity, and potential pathophysiological reactions. Besides, we explore how sodium consumption enhances the expression of transient receptor potential channel 3 (TrpC3) mRNA and facilitates the release of calcium inside immune cell groups, together with elevated blood pressure in essential hypertensive patients.

Self-monitoring urinary salt excretion device can be used for controlling hypertension for developing countries

Restriction of dietary salt is widely recommended in the management of hypertension, but assessment of individual salt intake has drawn little attention. Monitoring nutritional salt intake through sodium excretion has been popular, because the main route for sodium (Na) excretion is through the urine. Nonetheless, direct measurement of dietary salt intake is time consuming and lacks accuracy. To collect a 24-h urine and measure the content is difficult method for most patients. In this review paper, we would like to explore the usefulness of measuring urinary salt excretion by using a self-monitoring device at home. Measuring daily overnight urine by the self-monitoring device at home will be useful for the management of hypertension suitable for each individual. From the recent increase of processed foods, the term “salt intake” would not accurately be equal to “sodium intake”. Devices measuring urinary sodium excretion have been developed and evaluated on their accuracy and correlation with sodium intake. They must be handy, simple and capable of measuring large populations to be useful for monitoring of daily salt intake and to guide salt restriction as well as the long-term effects by dietary salt intake.