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Background: Insulin resistance and renal tubular sodium handling influence arterial structure and function and play an essential role in salt-sensitive forms of hypertension., Methods: In a population with prevailing sodium consumption, we assessed the relationship between cardiovascular phenotypes (peripheral and central blood pressures, elastic properties of large arteries, the left ventricular structure) and sodium handling parameters (daily urinary sodium excretion, fractional urinary lithium excretion in proximal-FELi and distal tubules), as a function of insulin sensitivity-measured by homeostasis model assessment-insulin resistance (HOMA-IR), leptin-to-adiponectin (L/A) ratio, and homeostasis model assessment-adiponectin (HOMA-AD)., Results: In patients with FELi below the median value (corresponding to the group with increased proximal sodium reabsorption) and higher insulin resistance as measured by HOMA-IR, pulse wave augmentation indexes were significantly higher-AIxP (99.4% vs. 86.2%; P = 0.007), AIxC1 (159.4% vs. 144.2%; P = 0.04), and AIxC2 (36.1% vs. 28.3%; P = 0.02), than in patients with lower insulin resistance. The same trend was observed in relation to L/A ratio-AIxP (98.7% vs. 87.1%; P = 0.005), AIxC1 (158.6% vs. 144.5%; P = 0.02), and AIxC2 (35.6% vs. 28.5%; P = 0.01) and HOMA-AD-AIxP (99.7% vs. 83.8%; P = 0.001), AIxC1 (160.5% vs. 140.3%; P = 0.007), and AIxC2 (36.6% vs. 26.3%; P = 0.003). Such relationships were not observed in patients with FELi above the median value., Conclusions: In the hypertensive population with prevailing sodium intake, insulin resistance and increased sodium reabsorption in proximal tubules may affect arterial wall function., (© American Journal of Hypertension, Ltd 2019. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Mounting evidence has associated high sodium (HS) intake with hypertension, cardiovascular disease, and stroke. We investigated whether HS intake modulates the parameters of endothelial damage, inflammation, and oxidative stress., Methods: We used a cross-sectional study design including 223 Chilean subjects (6.9-65.0 years old). We measured aldosterone, renin activity, cortisol, cortisone, adiponectin, leptin, hsCRP, interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), plasminogen activator inhibitor type 1 (PAI-1), metalloproteinase (MMP)-9 and MMP-2 activity, and malondialdehyde. Sodium and creatinine were measured in 24-hour urine samples. The subjects were divided by sodium intake, high sodium (HS): ≥150 mEq/day, n = 118, and adequate sodium (AS): <150 mEq/day, n = 105., Results: We observed a positive correlation between urinary sodium excretion and blood pressure (r = 0.1669, P = 0.0124 for systolic and r = 0.2416, P = 0.0003 for diastolic), glycemia (r = 0.2660, P < 0.0001), and triglycerides (r = 0.1604, P = 0.0175) and a highly significant correlation between sodium excretion and PAI-1 (r = 0.2701, P < 0.0001). An inverse correlation was observed between urinary sodium and HDL-cholesterol (r = -0.2093, P = 0.0018) and adiponectin (r = -0.2679, P < 0.0001). In a linear regression model, urinary sodium excretion remained significantly associated with PAI-1 values even after adjusting for age, gender, and BMI. The HS group had higher blood pressure, glycemia, HOMA-IR, atherogenic index of plasma, and PAI-1 values than the group with AS intake., Conclusions: HS intake is associated with endothelial damage (high PAI-1) and metabolic dysregulation. On the other hand, inflammation and oxidative stress parameters are not modified by sodium intake.

Background: High sodium intake has been associated with various noncommunicable disease like hypertension, cardiovascular disease, or stroke. To estimate accurately sodium intake is challenging in clinical practice. We investigate the usefulness and limitations of assessing sodium intake simultaneously by dietary assessment and urinary samples in both children and adults., Methods: We used a cross-sectional study design inviting 298 Chilean subjects (74 children and 222 adults) aged between 9 and 66 years of both genders. Sodium intake by dietary assessment was obtained from Chilean food composition data, based on FAO tables. Sodium and creatinine excretion were measured in 24-hour urine samples, in all participants., Results: Adequate urinary collection was obtained in 81% of children (59/74) and 61% of adults (135/222). The mean sodium intake by dietary assessment was similar to the sodium excretion in 24 hours (3,121±1,153mg/d vs. 3,114±1,353mg/24h, P = nonsignificant) in children but was significantly lower (3,208±1,284mg/d vs. 4,160±1,651mg/24h, P < 0.001) in adults. In both children and adults, sodium intake correlated with urinary sodium excretion (r = 0.456, P < 0.003 and r = 0.390, P < 0.001, respectively). Secondary analyses also suggested that the dietary assessment was more inaccurate in overweight adult subjects., Conclusions: Our results showed that average sodium intake was higher than recommended in both children and adults (WHO ≤2,000mg/d). The sodium intake estimated by dietary assessment correlated with urinary excretion in all subjects, but in obese adults was more inaccurate than in children. Future studies to validate the appropriate test to assess sodium intake by age and nutritional status are warranted., (© American Journal of Hypertension, Ltd 2016. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: LCZ696, an angiotensin receptor-neprilysin inhibitor, has recently been demonstrated to exert more beneficial effects on hypertensive or heart failure patients than conventional renin-angiotensin system blockers. However, the mechanism underlying the benefit of LCZ696 remains to be understood. The present study was undertaken to examine the effect of LCZ696 compared with valsartan on hypertension and cardiovascular injury., Methods: (i) Using telemetry, we compared the hypotensive effect of LCZ696 and valsartan in spontaneously hypertensive rats (SHR) that were fed a high-salt diet followed by a low-salt diet. (ii) We also examined the comparative effect of LCZ696 and valsartan on salt loaded SHRcp, a model of metabolic syndrome., Results: (i) LCZ696 exerted a greater blood pressure (BP) lowering effect than valsartan in SHR regardless of high-salt or low-salt intake. Additive BP reduction by LCZ696 was associated with a significant increase in urinary sodium excretion and sympathetic activity suppression. (ii) LCZ696 significantly ameliorated cardiac hypertrophy and inflammation, coronary arterial remodeling, and vascular endothelial dysfunction in high-salt loaded SHRcp compared with valsartan., Conclusions: LCZ696 caused greater BP reduction than valsartan in SHR regardless of the degree of salt intake, which was associated with a significant enhancement in urinary sodium excretion and sympathetic activity suppression. Furthermore, an additive BP lowering effect of LCZ696 led to greater cardiovascular protection in hypertensive rats., (© American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: The effect of sodium intake on the cardiovascular system remains controversial. The purpose of this study is to investigate the relation between sodium intake and cardiovascular structure and function in the nonhypertensive population., Methods: We performed a cross-sectional analysis in 1,586 nonhypertensive subjects who participated in the Korean Genome Epidemiology Study (2007-2008). Sodium intake was assessed by estimating the 24-hour urinary sodium excretion from a spot urine sample. Changes in cardiovascular structure and function were assessed by using tissue Doppler echocardiography, the carotid intima-media thickness (CIMT), and the brachial-ankle pulse wave velocity (baPWV)., Results: Systolic and diastolic blood pressures increased with increasing tertiles of estimated 24-hour urinary sodium excretion. In multivariate analyses adjusting for covariates, there were stepwise decreases in the baPWV (P = 0.003) and CIMT (P = 0.001) values as the estimated 24-hour urinary sodium excretion increased, whereas no significant differences in left ventricular (LV) structural and functional parameters were observed across the tertiles of estimated 24-hour urinary sodium excretion. Multiple linear regression analyses revealed that the estimated 24-hour urinary sodium excretion was independently and inversely associated with baPWV (P < 0.001) and CIMT (P = 0.001), but not with LV parameters., Conclusions: In the nonhypertensive population, urinary sodium excretion was inversely related to baPWV and CIMT. However, there were no associations between urinary sodium excretion and LV structure or function., (© American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Hypertension is a common disease in patients with chronic kidney disease (CKD) and predisposes to heart disease, stroke, and progression of renal failure. In the general population, sodium restriction has been shown to improve blood pressure (BP) control, but this is not widely recommended in CKD patients. The aim of this study was to assess the sodium balance in a CKD clinic and its effect on BP management., Methods: We retrospectively reviewed charts from June 1998 through to June 2003 and included all patients with an estimated glomerular filtration rate (GFR) of <30 mL/min who completed a 24-h urine collection for sodium. Patients were divided into tertiles based upon their 24-h sodium excretion and analyzed by ANOVA., Results: We included 141 CKD patients who had a mean (+/- SE) sodium excretion of 145.7 +/- 4.7 mmol/day. There were a significantly greater number of antihypertensive agents used with increasing sodium excretion (2.00 +/- 0.16, 2.61 +/- 0.20, and 2.77 +/- 0.19 medications, respectively for each tertile; P = .01). This difference was even more prominent when only those patients with a GFR

The associations of the beta-adducin C1797T polymorphism with blood pressure (BP) and various indexes of sodium homeostasis were investigated in 388 men and 456 women, aged 18 to 60 years, recruited from three European populations (Cracow, Poland, n = 300; Novosibirsk, Russian Federation, n = 274; Mirano, Italy; n = 270). Phenotypes included 24-h ambulatory BP and urinary excretion of electrolytes and aldosterone. Subjects were genotyped for the beta-adducin polymorphism. Both a population-based association study and a family-based analysis were performed. Urinary sodium excretion was higher in Cracow than in Mirano (241 v 185 mmol/24 h, P <.05) and intermediate in Novosibirsk (206 mmol/24 h). The beta-adducin T allele (15.2% v 9.1%, P <.0001) was more prevalent in Mirano than in the two Slavic centers. In both population-based and family-based association analyses, there was significant heterogeneity between Slavic and Italian subjects in the phenotype-genotype relationships with beta-adducin. In the Slavic centers, 24-h systolic BP was higher in T allele carriers than in CC homozygotes (122.3 v 119.7 mm Hg, P =.03), whereas this was not the case in Mirano (121.8 v 122.9 mm Hg, P =.42). In Slavic (212.6 v 233.1 mmol/24 h) as well as in Italian (166.1 v 191.5 mmol/24 h) participants, 24-h sodium excretion was lower (P =.01) in T allele carriers than in CC homozygotes. These results were confirmed in the family-based analysis of offspring using a quantitative transmission disequilibrium test. In conclusion, the frequency of the beta-adducin T allele and salt intake differ across European populations. Thus, both variation in genetic background and salt intake may explain the observed heterogeneity in the phenotype-genotype relationships. Genetic determinants of complex quantitative traits such as BP can only be investigated within their epidemiologic context.

Background: Dopamine D(2) receptors (D(2)Rs) are expressed in the kidney. It has not been determined whether D(2)Rs are involved in the mechanism of sodium handling and blood pressure (BP) control., Methods: The function of D(2)Rs was investigated in mice disrupted with D(2)R gene (D(2)KO mice). Six-week-old male D(2)KO mice and wild-type (WT) mice were fed high-salt (4% NaCl) or low-salt (0.01% NaCl) diets for 8 weeks., Results: Before starting the metabolic diet, there were no significant differences in body weight, food consumption, and 24-h urine excretions of creatinine, sodium and potassium. The high-salt diet caused a significant elevation in systolic BP in D(2)KO mice but not in WT mice. Calculation of sodium and potassium balances revealed a significantly high level of sodium retention in D(2)KO mice placed on the high-salt diet. Twenty-four-hour urine norepinephrine excretions and heart rates, indicators of sympathetic activity, were not different in D(2)KO and WT mice on the high-salt diet. Administration of nemonapride, a specific D(2)-like receptor antagonist, to WT mice given 0.9% NaCl in drinking water caused suppression of urinary sodium excretion but had no effect in mice without salt loading., Conclusions: These results suggest that D(2) receptors promote sodium excretion during a period of high salt intake. A defect in this mechanism may result in sodium-dependent BP elevation.

Background: Impairment of renal dopamine excretion on high-salt diet (HS) may account for increased blood pressure (BP) in hypertensive subjects. Whether such impairment of dopaminergic activity exists in the adrenal gland is unknown. The purpose of this study was to differentiate degrees of dopaminergic inhibition of aldosterone secretion in patients with aldosterone-producing adenoma (APA)., Methods: A total of 15 patients with unilateral APA were fed a low-salt diet (LS) for 1 week, followed by another week on HS. At the end of each diet period, 24-h ambulatory BP recording, daily urine catecholamine measurement, and a metoclopramide test were performed., Results: A high-salt diet increased both daytime and nighttime BP (P < .001), and urine dopamine excretion (P < .01). Intravenous injection of 10-mg metoclopramide increased plasma aldosterone concentrations (PAC) on both diets. The areas-under-the-curve for PAC between LS and HS were not different, but the area-under-the-curve for PAC increment was greater on HS (P < .05). Six patients with increment areas on HS greater than those on LS by 50% were termed "suppressible," and the remainders as "nonsuppressible." On HS, the so-called suppressible subjects had greater urine dopamine and less urine norepinephrine excretions (P < .05). The nonsuppressible subjects had greater percentage increase of nighttime BP by HS than the suppressible (for systolic BP, 13.1% v 4.5%, P < .01; for mean BP, 12.0% v 5.1%, P < .01, respectively), but no difference in daytime BP., Conclusions: Two subtypes of APA were defined according to their responses to metoclopramide during salt manipulation. On HS, the nonsuppressible subjects, with less dopaminergic inhibition of aldosterone secretion, had less urinary DA excretion and greater BP elevation. The renal and adrenal dopaminergic activities are regulated in a parallel fashion.

Background: Individuals differ in their blood pressure (BP) response to changes in dietary sodium (Na+) intake. It is possible that differences in BP responses to dietary Na+ are influenced by genes., Methods: A total of 35 older (62.9 +/- 1.2 years) hypertensive subjects had their mean arterial blood pressure (MABP) determined after 8 days of low (20 mmol/day) and high (200 mmol/day) Na+ intake. The insertion/ deletion polymorphism of the angiotensin converting enzyme (ACE) gene was genotyped with standard polymerase chain reaction methods., Results: Of the 35 subjects, 24 were classified as sodium-sensitive (> or = 5 mm Hg increase in MABP in response to the increase in dietary Na+) and 11 were classified as sodium-resistant (<5 mm Hg increase in MABP). Those homozygous for the insertion allele of the ACE gene (insertion/insertion [II]; n = 8) had lower (P = .04) MABP responses to the increase in dietary Na+ (0 +/- 3 mm Hg) compared to heterozygotes (insertion/deletion [ID]; n = 20) (9 +/- 2 mm Hg; P = .0001) and those homozygous for the deletion allele (deletion/deletion [DD]; n = 7) (9 +/- 3 mm Hg; P = .05). The prevalence of sodium sensitivity was higher (P = .0083) in DD (71%) and ID (83%) compared to II (25%) genotype groups., Conclusions: Based on these data in older hypertensive individuals, we conclude that the ACE gene ID and DD genotypes are associated with an increase in BP during a high Na+ diet, which is consistent with the phenotypic characteristic of sodium sensitivity.

The present study examines the responses of plasma atrial natriuretic peptide (ANP), aldosterone and plasma renin activity to small alterations in dietary sodium intake. Six normotensive subjects were equilibrated on a low sodium intake of 10 mmol/day for 4 days. Dietary sodium intake was then increased gradually by 50 mmol/day to a maximum of 350 mmol/day over a 7 day period. With the gradual increase in sodium intake there were progressive increases in urinary sodium and cumulative sodium balance. These were associated with gradual increases in plasma ANP and reductions in both plasma aldosterone and plasma renin activity. During the study there were no significant changes in blood pressure, urinary potassium and creatinine clearance. This study demonstrates a marked sensitivity of the responses of both the ANP and the renin-aldosterone system to small changes in sodium intake and points to their importance in the renal adaptations to small alterations in dietary sodium intake.