Correlation of excess salt intake identified by the survey with urine sodium level and blood pressure: data of ESSE-RF study

Aim. To study the association of blood pressure (BP) and hypertension (HTN) with salt intake estimated by the survey and the urinary Na+ concentration among men and women 25-64 years old, examined within the ESSE-RF and ESSE-RF-2 studies.Material and methods. Representative samples of the Russian population aged 25-64 years were examined. At the first phase in 2012-2014, 21,888 people (men — 38,2%) were included, and at the second phase in 2017 — 6,714 people (men — 44,7%). The response rate was 80%. We used standard questionnaire. Adding more salt and the consumption of salted foods (sausages, deli meats, and pickled foods) in the criteria “daily or almost daily” was considered excess salt intake (ESI). BP measurement was carried out in a sitting position on the right hand. BP was measured twice with an interval of about 2-3 minutes. HTN was diagnosed at a systolic BP (SBP) ≥140 mm Hg and/or diastolic BP ≥90 mm Hg, or in case of antihypertensive therapy. In ESSE-RF-2, an analysis of the morning urine was additionally performed. Na+ was determined using the EX-Ds ion-selective electrolyte analyzer. All participants were stratified by the quintiles of urine sodium level. Data analysis was performed using the software package R 3.6.1. The models of linear and logistic regression were used. The differences were considered at p<0,05.Results. The average level of SBP significantly increases with an increase in Na+ in urine: 1,04 (0,60-1,48) mm Hg for the quintile of sodium distribution (p<0,001), the odds of HTN increases by 1,11 (1,05-1,17) times for the quintile (p<0,001). Questionnaire components of ESI are also significantly related to urinary Na+ levels. The consumption of sausages and deli meats has the greatest effect, causing an increase in the average Na+ level by 11,59 (7,06-16,12) mmol/l (p<0,001). The applied point scale is significantly related to urine sodium level and predicts HTN no worse than Na+ in the urine (p=0,15 for the difference hypothesis). One point on the scale increases the Na+ level by an average of 7,51 (5,01-10,02) mmol/l, SBP by an average of 0,74 (0,41-1,07) mm Hg and the odds of HTN by 1,1 (1,06-1,15) times (p<0,001 for all).Conclusion. In the pattern of ESI components, processed meat and sausage products take first place in terms of association strength with urine sodium. The questionnaire used to assess the proportion of people with ESI can be recommended for assessing this risk factor during screening. ESI detected by the questionnaire is associated with elevated BP and urinary Na+ values.

Emerging evidence of an effect of salt on innate and adaptive immunity

Salt intake as part of a western diet currently exceeds recommended limits, and the small amount found in the natural diet enjoyed by our Paleolithic ancestors. Excess salt is associated with the development of hypertension and cardiovascular disease, but other adverse effects of excess salt intake are beginning to be recognized, including the development of autoimmune and inflammatory disease. Over the last decade there has been an increasing body of evidence demonstrating that salt affects multiple components of both the innate and adaptive immune systems. In this review we outline the recent laboratory, animal and human data, highlighting the effect of salt on immunity, with a particular focus on the relevance to inflammatory kidney disease.

Salt content in bread in Spain, 2014

Introduction: Excess salt intake is associated to the risk of high blood pressure and cardiovascular disease. Bread is one of the foods that contributes the most salt to the diet in Spain. It is important to monitor the salt content of bread.Objective: To quantify the amount of salt in bread in Spain in 2014, and to compare it to the amount of salt in 2008.Methods: This Cross-sectional study was conducted in Spain in 2014. 1,137 loaves of bread (barra, a Spanish style of bread, similar in shape to a baguette, baguettes and wholemeal) were purchased at bakeries with and without on-site workrooms and at supermarkets in all of Spain’s Autonomous Communities. Salt content (g/100 g bread) was analysed by determining total sodium. In one subsample, 2014 mean salt content was compared to previous data of 2008 salt content (chloride determination).Results: The mean salt content was 2.08 g (SD: 0.32) with a minimum value of 0.30 and a maximum of 3.33. The mean salt content was similar in barra- and baguette-type breads (2.09 g) and somewhat lower in wholemeal. The mean salt was 2.07 g/100 g in breads made with fresh dough and 2.12 g/100 g in breads made with frozen dough. The mean salt content (chlorides) was 1.64 g (SD: 0.42) in 2014 and 1.63 g (SD: 0.37) in 2008. This was not a significant difference (p=0.428).Conclusions: The amount of salt in common bread in Spain remains stable from 2008.

Abstract P332: Dietary Salt Intake and Blood Pressure Control in Hypertensive Individuals Under Antihypertensive Treatment During 7 Years

Purpose: Excess salt intake is one of the most important causes of hypertension. Salt restriction is a key strategy in the management of hypertension and, thus, should be instructed for hypertensive patients under medical treatment. We investigated recent changes in dietary salt intake and blood pressure (BP) levels in hypertensive patients. Methods: Total of 12422 hypertensive subjects (male 71.0% [8814 of 12422], 64.6±9.2 year-old) under medical treatment who visited our hospital for a physical checkup from 2010 to 2016 were enrolled. They were divided into 3 groups according to the number of antihypertensive drugs prescribed (1, 2 and ≥3 drugs). Cross-sectional analyses were performed using data in each year and changes during the 7 years were investigated. Individual salt intake was estimated using a spot urine by a previously reported method. Results: BP levels and the accomplishment rate of the target BP (<140/90mmHg) were improved in each group during the 7 years without significant difference among the groups (Overall 2010 to 2016; BP 132.7±13.6/80.0±8.9 to 128.8±13.7/76.3±9.6 mmHg and accomplishment ratio 65.6 [968 of 1475] to 76.4% [1433 of 1875]). However, individual salt intake was gradually increased in all groups (2010 to 2016 in 1, 2, and ≥3 drugs; 11.7±3.7 to 12.2±4.0, 11.9±3.7 to 12.7±3.9, and 12.2±3.9 to 12.9±4.1 g/day, respectively) and the accomplishment rate of salt restriction (<6g/day) was significantly reduced in subjects with increased number of antihypertensive drugs (3.5 [225 of 6435], 2.8 [125 of 4564], and 2.3% [33 of 1423] in groups with 1, 2, and ≥3 drugs, respectively). The accomplishment rate of the target BP was significantly higher in patients who achieved salt restriction than in those who did not achieve salt restriction in all groups (Over all; 80.2 [307 of 383] vs. 73.3% [8829 of 12039]). Conclusions: The control of BP in individuals with antihypertensive medications was improved in the last 7 years. However, salt restriction has not been successfully achieved especially in hypertensive patients with multiple antihypertensive medications. Excess salt intake may induce resistance to antihypertensive treatment and, thus, increases the number of antihypertensive drugs for BP control.

Genome-wide analysis of gestational gene-environment interactions in the developing kidney

The G protein-coupled bradykinin B2 receptor (Bdkrb2) plays an important role in regulation of blood pressure under conditions of excess salt intake. Our previous work has shown that Bdkrb2 also plays a developmental role since Bdkrb2−/− embryos, but not their wild-type or heterozygous littermates, are prone to renal dysgenesis in response to gestational high salt intake. Although impaired terminal differentiation and apoptosis are consistent findings in the Bdkrb2−/− mutant kidneys, the developmental pathways downstream of gene-environment interactions leading to the renal phenotype remain unknown. Here, we performed genome-wide transcriptional profiling on embryonic kidneys from salt-stressed Bdkrb2 +/+ and Bdkrb2 −/− embryos. The results reveal significant alterations in key pathways regulating Wnt signaling, apoptosis, embryonic development, and cell-matrix interactions. In silico analysis reveal that nearly 12% of differentially regulated genes harbor one or more Pax2 DNA-binding sites in their promoter region. Further analysis shows that metanephric kidneys of salt-stressed Bdkrb2−/− have a significant downregulation of Pax2 gene expression. This was corroborated in Bdkrb2 −/−; Pax2 GFP+/tg mice, demonstrating that Pax2 transcriptional activity is significantly repressed by gestational salt-Bdkrb2 interactions. We conclude that gestational gene ( Bdkrb2) and environment (salt) interactions cooperate to impact gene expression programs in the developing kidney. Suppression of Pax2 likely contributes to the defects in epithelial survival, growth, and differentiation in salt-stressed BdkrB2 −/− mice.

Hypertensive response to chronic NG-nitro-l-arginine methyl ester (l-NAME) treatment is similar in immature and adult Wistar rats

The aim of our study was to evaluate whether the blood pressure (BP) response to chronic inhibition of NO synthase (NOS) is exaggerated in young rats, which were reported to develop a more pronounced salt hypertension than the adult ones. The enhanced BP rise in immature rats subjected to excess salt intake might be due either to a generally increased reactivity in immature organisms to these stimuli or to a greater impairment of NO bioavailability that accompanies the development of salt hypertension. To determine between the two alternatives, we have compared the hypertensive response and the extent of NOS inhibition in immature (4-week-old) and adult (12-week-old) male Wistar rats which were treated with NG-nitro-L-arginine methyl ester (L-NAME, 40 mg/kg of body mass per day) for 4 weeks. BP and NOS activity in the aorta, left ventricle and kidney were determined at the end of the experiment. It should be noted that chronic L-NAME treatment caused a similar degree of NOS inhibition in both age groups (irrespective of tissue examined). There was no significant difference in BP elevation between young and adult animals chronically treated with L-NAME. A strong negative correlation between NOS activity and BP level was observed in separate groups of normotensive controls and L-NAME hypertensive rats. Thus the BP of both normotensive and hypertensive animals seems to be inversely proportional to the production of NO. It can be concluded that there was the same BP rise in both age groups of L-NAME-treated rats in which a similar degree of NOS inhibition was disclosed. This suggests that the altered NO bioavailability (but not the generally exaggerated reactivity to hypertensive stimuli) is the cause of exaggerated hypertensive response observed in immature rats exposed to excess salt intake.