Blockade of Endogenous Angiotensin-(1-7) in Hypothalamic Paraventricular Nucleus Attenuates High Salt-Induced Sympathoexcitation and Hypertension / 神经科学通报·英文版

Angiotensin (Ang)-(1-7) is an important biologically-active peptide of the renin-angiotensin system. This study was designed to determine whether inhibition of Ang-(1-7) in the hypothalamic paraventricular nucleus (PVN) attenuates sympathetic activity and elevates blood pressure by modulating pro-inflammatory cytokines (PICs) and oxidative stress in the PVN in salt-induced hypertension. Rats were fed either a high-salt (8% NaCl) or a normal salt diet (0.3% NaCl) for 10 weeks, followed by bilateral microinjections of the Ang-(1-7) antagonist A-779 or vehicle into the PVN. We found that the mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and plasma norepinephrine (NE) were significantly increased in salt-induced hypertensive rats. The high-salt diet also resulted in higher levels of the PICs interleukin-6, interleukin-1beta, tumor necrosis factor alpha, and monocyte chemotactic protein-1, as well as higher gp91 expression and superoxide production in the PVN. Microinjection of A-779 (3 nmol/50 nL) into the bilateral PVN of hypertensive rats not only attenuated MAP, RSNA, and NE, but also decreased the PICs and oxidative stress in the PVN. These results suggest that the increased MAP and sympathetic activity in salt-induced hypertension can be suppressed by blockade of endogenous Ang-(1-7) in the PVN, through modulation of PICs and oxidative stress.

Effects of Chronic Salt Loading on Plasma Inflammatory Factors in Normotensive Adults / 中国循环杂志

Objectives: To observe the effects of dietary sodium intake on plasma inflammatory factors including tumor necrosis factor alpha (TNF-α), high-sensitivity C-reactive protein (CRP) and monocyte chemoattractant protein -1 (MCP-1) in normotensive adults. Methods: Thirty normotensive volunteers, aged 18 to 60 years old, were selected to undergo baseline survey, low-sodium diet (51.3 mmol per day) for 7 days, followed by high-sodium diet (307.8 mmol per day) for 7days. Subjects were classified as salt sensitive (SS, 10 subjects) or non-salt sensitive (NSS, 20 subjects) based on their mean arterial blood pressure (MAP) increase (SS: more than 10 percent increase at the end of the high-sodium phase compared with the end of low-sodium phase). Fasting blood samples were taken on the first day of baseline and on the sixth day of the two intervention phases. Plasma TNF-α and MCP-1 concentration was measured using an enzyme-linked immunosorbent assay system, plasma hs-CRP concentration was measured by immune nephelometry. Results: The prevalence of SS is 33%. After salt loading, no significant change was found in the plasma hs-CRP concentrations; Whereas plasma TNF-α level increased significantly in both of the SS and NSS groups(pg/ml, [168.4±67.8 vs 42.1±26.7], P<0.01 and [129.8±24.1 vs 37.7±15.8], P<0.01, respectively) ; Plasma MCP-1 was also significantly higher during the high-sodium than the low-sodium phase in both SS and NSS groups(pg/ml, [205.2±64.2 vs 166.3±48.5], P<0.01and [212.3±52.2 vs 143.6±55.9], P<0.01). Conclusions: High-sodium diet can induce an inflammatory state independent of the salt sensitivity in normotensive subjects.

The vascular endothelial function damage as well as early atherosclerosis in hypertensive youth / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore young hypertensive people's vascular endothelial dysfunction and the early atherosclerosis changes.</p><p><b>METHODS</b>Rural youth subjects aged 20 to 35 in 6 villages were randomly selected from 20 villages of 3 townships, including Qili, Laojun and Shayan, in Hanzhong, Shanxi, China, from March to April of 2005, to survey their blood pressure and other related factors. 97 subjects with high blood pressure (hypertensive group) were detected while 400 with normal blood pressure (normal group). We measured their brachial artery flow-mediated vascular endothelial-dependent diastolic function (FMD) and the carotid intima-media thickness (IMT) by high resolution vascular ultrasound method, and other biochemical indexes.</p><p><b>RESULTS</b>The body mass index (BMI) ((24.7 ± 4.3) kg/m²), waistline ((84.1 ± 11.7) cm), hipline ((92.5 ± 7.4) cm), TC ((4.6 ± 0.8) mmol/L), LDL-C ((2.8 ± 0.5) mmol/L), TG ((1.7 ± 1.1) mmol/L) and the blood insulin (INS) ((8.6 ± 4.4) mIu/L) were all significantly increased in young hypertensive group than those in normotensive group (respectively were (22.1 ± 3.0) kg/m(2), (76.7 ± 8.9) cm, (88.9 ± 5.6) cm, (4.3 ± 0.7) mmol/L, (2.6 ± 0.4) mmol/L, (1.4 ± 0.8) mmol/L and (6.9 ± 2.1) mIu/L) (P < 0.05). The FMD of the brachial artery in hypertensive group was markedly lower than normal group ((0.103 ± 0.04)% and (0.117 ± 0.05)%, P < 0.05). The IMT of two groups were (0.49 ± 0.07) mm and (0.48 ± 0.07) mm, but there was no statistically significant differences (P > 0.05).</p><p><b>CONCLUSION</b>Young hypertensive people with a few cardiovascular risk factors earlier appear dysfunction of the flow-mediated vascular endothelial-dependent dilation, which is prior to the increase in carotid IMT.</p>

Vascular endothelial function in salt sensitive and non-salt sensitive subjects / 中华心血管病杂志

<p><b>OBJECTIVE</b>Salt-sensitivity is associated with more severe target organ injury and higher mortality in patients with essential hypertension. We compared the vascular endothelial function between salt-sensitive subjects (SS) and non-salt-sensitive subjects (NSS) with normal or mildly increased blood pressure.</p><p><b>METHODS</b>Ninety-nine subjects (aged 16 - 60 years) with normal blood pressure or mild hypertension (degree 1) were enrolled. The test program included 3 days baseline investigation, 1 week low-salt loading phase and 1 week high-salt loading phase. Endothelial function was assessed by measuring the flow mediated dilatation (FMD) of the brachial artery using high resolution ultrasound.</p><p><b>RESULTS</b>There was 17.2% SS. Plasma NOx level [(61.2 ± 13.3) µmol/L vs (82.5 ± 14.6) µmol/L, P < 0.05] and FMD [(10.2 ± 2.5)% vs (14.5 ± 1.6)%, P < 0.05] were significantly lower in SS subjects than in NSS subjects.</p><p><b>CONCLUSION</b>Vascular endothelial dysfunction was evidenced in SS subjects with normal blood pressure or in the early stage of hypertension.</p>

Association between higher blood pressure level in children and adult blood pressure: 17 years follow-up results / 中华心血管病杂志

<p><b>OBJECTIVE</b>Essential hypertension may begin at childhood. The aim of this study is to identify the risk factors of hypertension and detect the evolvement tracking of blood pressure in childhood.</p><p><b>METHODS</b>In this study, we followed up blood pressure changes in 4623 school children (6 - 15 years-old) from 1987 to 2005 in Hanzhong rural area. A total of 152 children were grouped to higher blood pressure group [systolic blood pressure (P(SBP)) >or= 75(th) (P(75))] and 140 children grouped to normal blood pressure group [P(SBP) < 50(th) (P(50))] and their blood pressure were re-measure 18-years later.</p><p><b>RESULTS</b>The total follow-up rate was 70.2%. Follow-up blood pressure was significantly higher in higher blood pressure group at baseline than that in normal blood pressure group at baseline (P < 0.05). The hypertension rate at follow up was significantly higher in higher blood pressure group at baseline than that in normal blood pressure group at baseline (28.0% vs. 4.1%, P < 0.01). The risk for hypertension was 6.88 greater in higher blood pressure group at baseline than that in normal blood pressure group at baseline.</p><p><b>CONCLUSIONS</b>Higher blood pressure at childhood is a risk of developing hypertension at adulthood.</p>

Salt-Sensitivity and Developement of Blood Pressure From Adolescents to Youth / 中华高血压杂志

Objective To study the effects of salt sensitivity on evolution of blood pressure and develope- ment to hypertension from adolescents to youth.Methods A baseline survey was carried out in 4623 adolescents aged 6-15 years old in Hanzhong rural area in 1987,310 of them were recruited for determination of salt sensitiv- ity using the tests of oral saline load and furosemide sodium-volume depletion.Salt sensitivity (SS) were diag- nosed in 101 while 209 subjects as no-sah sensitivity (NSS).This cohort of adolescents were followed up for av- erage 18 years.Results The response rate for this cohort of adolescents was 71.9%.At the end of follow up period,BP in subjects with baseline SS was higher in youth than that in NSS (SBP:122.9?13.1 vs 117.3?12.4, P

Endothelial function evaluation in salt-sensitive normotensive and mild hypertensive subjects and effects of potassium supplement / 中华心血管病杂志

<p><b>OBJECTIVE</b>Salt-sensitivity plays an important role in essential hypertension and is associated with more severe target organ injury and higher mortality in patients with essential hypertension. However, the pathologic mechanism of salt-sensitivity is poorly understood and endothelial dysfunction might be involved in salt-sensitive hypertension. We, therefore, observed the endothelial function changes by measuring plasma and urine nitric oxide (NO) concentrations in salt-sensitive (SS) normotensive and mild hypertensive subjects underwent various salt loading protocols and the effects of potassium supplement.</p><p><b>METHODS</b>Thirty-nine normotensive and mild hypertensive subjects (< 160/100 mm Hg), aged 16-60, were enrolled and the study protocol is as follows: 3 days baseline investigation, 1 week low-salt loading (3 g/day), 1 week. high-salt loading (18 g/day) and 1 week high-salt loading plus potassium chloride (4.5 g/day).</p><p><b>RESULTS</b>Plasma and urine NO levels were significantly lower in SS (n = 8) subjects at baseline, low-salt and high-salt loading phases compared with salt-resistant subjects (SR, n = 31) and oral potassium supplement to SS subjects with high salt loading significantly increased plasma and urine NO levels.</p><p><b>CONCLUSION</b>Endothelial function is impaired in normotensive and mild hypertensive SS subjects. Oral potassium supplement could improve endothelial function in normotensive and mild hypertensive SS subjects.</p>

Blood pressure change with age in salt-sensitive teenagers / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.</p><p><b>METHODS</b>Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.</p><p><b>RESULTS</b>After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7 +/- 12.1 mmHg vs. 2.8 +/- 5.2 mmHg, P < 0.01; 12.2% +/- 12.0% vs. 2.5% +/- 4.4%, P < 0.001, respectively). There was a similar trend for diastolic blood pressure (8.4 +/- 6.4 mmHg vs. 3.7 +/- 6.4 mmHg, P = 0.052; 13.2% +/- 10.6% vs. 6.8% +/- 10.1%, P = 0.053, respectively).</p><p><b>CONCLUSIONS</b>Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.</p>

Long term observation in effects of potassium and calcium supplementation on arterial blood pressure and sodium metabolism in adolescents with higher blood pressure / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of potassium and calcium supplementation in table salt on reduction of arterial blood pressure and sodium metabolism in adolescents with higher blood pressure.</p><p><b>METHODS</b>A single blind placebo-controlled trial was carried out for two years in 220 adolescents with higher blood pressure, aged 18 - 22 years, who were randomly divided into supplementary group (n = 110) and control group (n = 110). Each of the subjects in the supplementary group and their family members was given 10 mmol of potassium and 10 mmol of calcium mixed in their table salt daily for 24 months.</p><p><b>RESULTS</b>Night urinary sodium and potassium excretion increased (urinary Na(+), P < 0.05; urinary K(+), P < 0.01) and blood pressure lowered by 5.3 mm Hg/1.8 mm Hg in average from the baseline in the supplementary group two years after potassium and calcium supplementation, as compared with that in the control group increased by (1.3/1.7) mm Hg.</p><p><b>CONCLUSIONS</b>Adequate supplement of potassium and calcium in daily table salt intake was an effective way to prevent form hypertension and could promote their urinary sodium excretion and reduction of arterial blood pressure in adolescents with higher blood pressure.</p>