Salt-sensitive Group Research Articles

Comparative Performance of Ionic and Agro-Physiological Traits for Detecting Salt Tolerance in Wheat Genotypes Grown in Real Field Conditions.

Studying the physiological mechanisms underlying the traits associated with salt tolerance in genotypes could lead to the discovery of new genetic resources for salt tolerance. In this study, the mechanisms of salt tolerance were evaluated, based on ionic, physiological, and agronomic traits in four varieties that differ in their salt tolerance and in 18 F8 recombinant inbred lines (RILs) grown in real field conditions. The salt tolerance of plant materials was assessed under both normal (3.5 mM NaCl) and high salinity stress (150 mM NaCl) conditions for two consecutive years. Different growth and physiological traits were assessed 75 days after sowing, while ion contents in the shoots, grain yield, and its components were determined at the maturity stage. Multivariate analysis was used to conduct a comprehensive evaluation of salt tolerance across various genotypes and traits. The ANOVA results showed significant differences (p ≤ 0.05 and 0.001) among salinity, genotypes, and their interactions for all ionic and agro-physiological traits, with a few exceptions. Salinity stress resulted in a considerable increase in Na+ content and canopy temperature (CT), with a simultaneous decrease of 11.3% to 94.5% in other ionic and agro-physiological traits compared to the control treatment. However, the salt-tolerant genotypes showed minimal increases in Na+ content and CT, as well as decreases in other ionic and agro-physiological traits when compared to salt-sensitive genotypes under salinity stress. All ionic and agro-physiological traits exhibited strong correlations with each other under salinity stress, but these correlations were weak or insignificant under control conditions. The principal component analysis identified Na+ and CT as negative indicators and other ionic and agro-physiological traits as positive indicators for salt tolerance under salinity stress. The negative indicators were strongly linked to salt-sensitive genotypes, while the positive indicators were closely associated with salt-tolerant genotypes. Heatmap clustering, using multiple traits, successfully differentiated the salt-tolerant genotypes from the salt-sensitive ones. The salt-tolerant group showed a significant reduction in Na+ content by 36.9%, in CT by 10.0%, and in HI by 16.7%, along with an increase of 6.3-51.4% in other ionic and agro-physiological traits compared to the salt-sensitive group. In conclusion, the mechanisms associated with Na+ exclusion and high K+/Na+ and Ca2+/Na+ ratios, as well as chlorophyll and relative water content, along with low CT, resulted in significant improvements in growth and yield under salinity stress conditions. Given that the effectiveness of various ionic and agro-physiological traits in evaluating salt tolerance in wheat has been proven in real field conditions, these traits will play a key role in the development of salt-tolerant wheat genotypes.

#4777 BLOOD PRESSURE RESPONSE TO A LOW SODIUM DIET IN NORMOTENSIVE SUBJECTS

Abstract Background and Aims The term salt sensitivity (SS) has been used to show an increase in BP in response to saline overload in both normotensive and hypertensive patients. Age, sex, and obesity have been proposed as predisposing factors. The objective of our work was to evaluate the response of office BP (OBP) and ambulatory BP (ABP) to changes in salt intake in healthy normotensive subjects. Method We analyzed 193 subjects who participated in the evaluation as potential kidney donors; none had a history of hypertension, diabetes, renal or cardiovascular disease. They received two consecutive standardized diets, one with 300 mEq and the other with 30 mEq of Na+/day. On the last day of each diet, a 24-h urine collection was obtained and an ambulatory BP monitor was placed for 24 h in the non-dominant arm, following recording of OBP. Data were expressed as mean and standard deviation (SD). Student's test and one-way ANOVA were used to compare means, values of p<0.05 were considered statistically significant differences. Results In the study group there were 120 females (62%) and 71 were salt sensitive (SS) (37%). The mean age was 46.9 ± 10 years (20 – 72) without significant gender differences (F = 46.7 ± 10 vs M = 47.3 ± 9 p = 0.704). The age of the salt sensitive (Ss) group was significantly higher than the salt resistant (Sr) (49.8 ± 9 vs 45.3 ± 10 p = 0.002). BMI was found to be increased (27.7 ± 4) without significant gender or incidence of SS differences. We found no association between gender and SS (p = 0.509). After the high sodium and before low sodium diets, the mean difference in urinary Na+ excretion was 165.2 ± 83 mEq/24h, significantly higher among men than women (201.6 ± 84 vs 142.3 ± 75 p = 0.0001). There were no differences based on SS. We did not find significant gender differences in the variation of OBP or ABP, with the changes in the diet. The mean reduction of systolic pressure OBP for the group was 6.13 ± 10 and of diastolic pressure OBP 0.35 ± 5 mmHg. In separate analysis, systolic and diastolic OBP drops were significantly higher in the Ss than in the Sr (9.69 ± 12 vs 2.57 ± 8 and 2.24 ± 7 vs – 0.95 ± 5 mmHg respectively, p = 0.001). The average reduction in systolic ABP was 7.13 ± 8 and in diastolic ABP 3.33 ± 5 mmHg. In separate group analysis we also observed a significantly greater reduction in Ss than in Sr (12.83 ± 7 vs 1.8 ± 5 and 6.56 ± 5 vs. 0.12 ± 3 mmHg respectively, p = 0.001). Conclusion In our study group, the reduction of both OBP and ABP following a low sodium diet in normotensive subjects depends on salt sensitivity and is independent of gender and body weight.

Pathogenesis of Higher Blood Pressure and Worse Renal Function in Salt-Sensitive Hypertension

Background: The underlying pathogenesis of patients with salt-sensitive hypertension expressing higher blood pressure and severer renal damage remains uncertain. Methods: We recruited 329 subjects, 131 in salt-sensitive (SS) group, 148 in nonsalt-sensitive (NSS) group, and 50 healthy people in normal group and tested their renal function, 24-h ambulatory blood pressure, and growth factor series. Results: The SS group showed worse renal function with lower estimated glomerular filtration rate and higher urinary microalbumin, α-microglobulin, urinary protein Cr ratio, and urinary immunoglobulin. Most indicators in 24-h ambulatory blood pressure of the SS group were significantly enhanced than the NSS group, indicating their higher blood pressure. The significantly elevated growth factors in the SS group were AR, BMP-5, EG-VEGF, GH, HGF, IGFBP-2, IGFBP-3, IGFBP-6, MCSFR, NT-4, PDGF-AA, SCF, SCFR, VEGFR2, VEGFR3, and VEGF-D, compared to other 2 groups or one of them. PI3K-AKT pathway was activated in the SS group. Conclusions: Differences in growth factors and pathways may account for the manifestations of the SS group. Activated PI3K-AKT pathway with higher IGFBP-3 and GH can lead to renal damage. Higher MCSFR in the SS group indicates that high blood pressure and severe kidney damage may be associated with the activation of the immune system. EG-VEGF, VEGFR2, VEGFR3, and VEGF-D can also explain the elevated blood pressure due to the dilated lymphatic system which drains excess sodium and water back into circulation. The SS group presented higher AR and HGF which may worsen renal function by regulating cell proliferation and tumor formation. However, due to the potential low awareness rate of hypertension at the very beginning, we cannot ensure the exact occurrence order of blood pressure, renal damage, and salt sensitivity. Therefore, further studies which can track data from the onset of hypertension are needed.

Transcriptome Sequencing to Detect the Potential Role of Long Noncoding RNAs in Salt-Sensitive Hypertensive Rats.

Backgrounds Long noncoding RNAs (lncRNAs) play an important role in various biological processes. However, their functions in salt-sensitive hypertension are largely unknown. In this study, the lncRNA-seq technique was employed to compare the expression profiles of lncRNAs and mRNAs in salt-sensitive hypertensive rats. Methods Blood pressure, serum sodium, and urinary creatinine were texted in salt-sensitive and salt-insensitive rats fed with different salt concentrations. High-throughput sequencing was used to detect the expression of lncRNAs and mRNA in the renal medulla of the two groups. Results Blood pressure and urinary sodium/creatinine of high-salt diets of the sensitive group were significantly higher than that in the control group. Serum sodium has no significant difference between the two groups in high-salt diets. NONRATG007131.2 and NONRATG012674.2 were the most different lncRNAs in the high salt-sensitive group. Correlation analysis reveals that Matn1, Serpinb12, Anxa8, and Hspa5 may play an important role in salt-sensitive hypertension. Conclusion This study analyzed the difference in lncRNA and mRNA between salt-sensitive and salt-insensitive rats with different salt diets by high-throughput sequencing. Salt sensitivity and salt concentration were two key factors for the induction of hypertension. We found some potential genes that play an important role in salt-sensitive hypertension.

Effectiveness of Chrono-Pharmacotherapy Depending on the Salt Sensitivity of Patients with Arterial Hypertension and Diabetes Mellitus Type 2

Aim. To study the effect of two regimens of combined antihypertensive therapy during the day on daily monitoring of arterial pressure, central aortic pressure, and arterial stiffness, depending on the salt sensitivity of hypertensive patients with diabetes mellitus type 2. Material and methods. 130 hypertensive patients with type 2 diabetes mellitus were included into the study. They were divided into 2 subgroups: salt-sensitive (group 1) and salt-resistant (group 2), and then randomized to subgroups A and B of ongoing therapy: in the morning ramipril and indapamide retard, bedtime – amlodipine (subgroup 1A and 2A); or in the morning amlodipine and indapamide retard, bedtime – ramipril (subgroup 1B and 2B). Initially and after 24 weeks of antihypertensive therapy, 24-hour blood pressure monitoring was performed, the indices of central aortic pressure and arterial stiffness were determined. Results. After 24 weeks, in all subgroups, there was a significant positive dynamics of the parameters of 24-hour blood pressure monitoring, central aortic pressure and arterial stiffness indices. In the subgroup 1В, it was registered a significant improvement in the majority of parameters of 24-hour blood pressure monitoring (decrease in 24-hours systolic BP by 24.4%, 24-hours diastolic BP by 22.1%; p<0.05), central aortic pressure (decrease in aortal systolic BP by 15.9%, aortal diastolic BP by 20.8%; p<0.05) and vascular wall stiffness parameters (decrease in pulse wave velocity by 13.8%; p<0.05) in comparison with group 1A (decrease in 24-hours systolic BP by 17.5%, 24-hours diastolic BP by 14.6%, aortal systolic BP by 12.7%, aortal diastolic BP by 9.7%, pulse wave velocity by 9.2%; p<0.05 in comparison with the group 1B). In the case of salt-resistant patients, there were comparable positive changes in the parameters of 24-hour blood pressure monitoring, central aortic pressure and arterial stiffness indices against the background of both dosing regimens during the day. Conclusion. In the study, it was demonstrated the more pronounced antihypertensive and vasoprotective efficacy of the combination of thiazide-like diuretic with calcium channel blocker in the morning and ACE inhibitor in bedtime compared to the alternative regimen of prescribed pharmacotherapy in salt-sensitive patients, and comparable efficacy of both regimens in salt-resistant hypertensive patients with diabetes mellitus type 2.

A11100 Effects of Chronic Salt Loading on Plasma Inflammatory Factors in Normotensive Adults

Objectives: To observe the effects of dietary sodium intake on plasma inflammatory factors 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, were selected to undergo a baseline survey, a low-sodium diet (51.3 mmol per day) for 7 days, a high-sodium diet (307.8 mmol per day) for an additional 7days. Thirty subjects were classified as salt sensitive group (SS, 10 subjects) or non-salt sensitive group (NSS, 20 subjects) on the basis of their mean arterial blood pressure (MAP) increase more than 10 percent at the end of the high-sodium phase compared with the 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 hsCRP concentration was measured by immune nephelometry. Results: The prevalence of SS is 33%. After salt loading, no significant change was found in the plasma hsCRP concentrations; Whereas plasma TNF-α level increased significantly in both of the two groups [(168.4 ± 67.8 vs. 42.1 ± 26.7)pg/ml, P < 0.01 and (129.8 ± 24.1 vs. 37.7 ± 15.8)pg/ml, P < 0.01, respectively]; Plasma MCP-1 was significantly higher during the high-sodium than the low-sodium phase in both of the two groups[(205.2 ± 64.2 vs. 166.3 ± 48.5)pg/ml, P < 0.01and (212.3 ± 52.2 vs. 143.6 ± 55.9)pg/ml, P < 0.01]. Conclusion: High-sodium diet can induce an inflammatory state, which may be independent of the salt sensitivity.

Sodium exclusion is a reliable trait for the improvement of salinity tolerance in bread wheat

ABSTRACTIdentification of novel wheat (Triticum aestivum L.) germplasm is imperative to develop salt tolerant varieties. In the first phase, 400 accessions were screened against high salt stress (200 mM NaCl) on the basis of Na+ accumulation in leaf blade, and 40 genotypes with contrast reaction to salinity were selected. Salt tolerant group (25 genotypes) had higher leaf K+/Na+ ratio, maximum root and shoot lengths, leaf fresh/dry weights and chlorophyll content as compared to the salt sensitive group (15 genotypes). In second phase, physiologically based screening was performed on selected genotypes against varying salinity levels (0, 100 and 200 mM NaCl). GGE biplot analysis indicates that genotypes TURACO, V-03094, V0005, V-04178, Kharchia 65 and V-05121 were the most salt-tolerant and declared winners as depicted by more gaseous exchange relations and growth potential which was strongly correlated with proper Na+, K+ discrimination in leaf and root tissues. Genotypes PBW343*2, NING MAI 50, PGO, PFAU, V-04181, PUNJAB 85, KIRITATI, TAM200/TUI and TAM200 were poor performer due to more Na+ accumulation in leaf ultimately retarded growth. In conclusion, low Na+ accumulation in leaf can be used as the best screening criteria, employing a large set of genotypes in a breeding program.

Potassium supplementation ameliorates increased plasma homocysteine induced by salt loading in normotensive salt-sensitive subjects

ABSTRACTThe mechanism by which high-salt and low-potassium diet contributes to hypertension remains poorly understood. Plasma homocysteine (Hcys) is recognized as a primary mediator of blood pressure (BP) response to some diets. Therefore, the present study tried to investigate whether plasma Hcys and BP could be regulated by salt loading in normotensive salt-sensitive (SS) persons, and further explored whether potassium supplementation could reverse the effect. We enrolled 47 normotensive subjects, aged 29–65 years. The protocol included 7 days on a low-salt diet (3g/day, NaCl), 7 days on a high-salt diet (18g/day), and then a high-salt diet with potassium supplementation (4.5g/day) for 7 days. After high-salt intake, BP was significantly increased and potassium supplementation lowered it in the SS group. Plasma Hcys were higher in SS subjects than in salt-resistant (SR) subjects after salt loading (34.4 ± 17.0 μmol/L versus 19.16 ± 6.4 μmol/L, P < 0.01). Plasma Hcys in SS subjects was increased on a high-salt diet than on a low-salt diet (34.4 ± 17.0 μmol/L versus 16.5 ± 8.3 μmol/L, P < 0.01), but plasma Hcys was ameliorated by potassium supplementation (34.4 ± 17.0 μmol/L versus 20.9 ± 10.4 μmol/L, P < 0.01). In SS subjects, the change of mean arterial blood pressure (MBP) correlated significantly and positively with the alteration of plasma Hcys during low-salt to high-salt intake and high-salt to high-salt with potassium supplementation (r = 0.75, P < 0.001; r = 0.74, P < 0.001, respectively). Our results indicate that Hcys may partly mediate the impact of high-salt intake and potassium supplementation on BP in SS subjects.

Modulatory effects of hydrochlorothiazide and triamterene on resistant hypertension patients.

The present study explored the modulatory potential of hydrochlorothiazide and triamterene on resistant hypertension patients. The mechanistic information for resistant hypertension was explored by studying the pressure-natriuresis curves between the salt sensitive population and non-salt sensitive population. A cohort of 23 patients with non-hypertension (NH) (13 males and 10 females; aged from 23 to 62 years), 26 patients with controlled hypertension (CH) (14 males and 12 females; aged from 19 to 72 years) and 23 patients with resistant hypertension (RH) (13 males and 10 females; aged from 19 to 76 years) were selected. The patients were divided into two main groups on the basis of salt sensitivity viz. salt sensitive (SS) and non-SS (NSS) groups. These two groups were further classified into four subgroups based on the diuretic drug used. Hydrochlorothiazide-treated subgroups were named as salt sensitive hydrochlorothiazide (SSHy) and non-SSHy (NSSHy) groups. Similarly, triamterene-treated subgroups were named as salt sensitive triamterene (SSTr) and non-SSTr (NSSTr) groups. Treatment continued for 2 weeks and the pressure-natriuresis curves were recorded. Additionally, the plasma aldosterone and renin activity was monitored by radioimmunoassay. The pressure-natriuresis curves of the SS group were shifted towards the right relative to NSS group. On the other hand, hydrochlorothiazide and triamterene treatments reversed the changes of pressure-natriuresis curves. Moreover, significant differences were observed among various important indices including plasma aldosterone, renin activity, office blood pressure as evaluated by the chronic salt load test and diuretic intervention tests. The study concludes that hydrochlorothiazide and triamterene hold good potential as an efficient modulator of resistive hypertension.

Mining and Analysis of SNP in Response to Salinity Stress in Upland Cotton (Gossypium hirsutum L.).

Salinity stress is a major abiotic factor that affects crop output, and as a pioneer crop in saline and alkaline land, salt tolerance study of cotton is particularly important. In our experiment, four salt-tolerance varieties with different salt tolerance indexes including CRI35 (65.04%), Kanghuanwei164 (56.19%), Zhong9807 (55.20%) and CRI44 (50.50%), as well as four salt-sensitive cotton varieties including Hengmian3 (48.21%), GK50 (40.20%), Xinyan96-48 (34.90%), ZhongS9612 (24.80%) were used as the materials. These materials were divided into salt-tolerant group (ST) and salt-sensitive group (SS). Illumina Cotton SNP 70K Chip was used to detect SNP in different cotton varieties. SNPv (SNP variation of the same seedling pre- and after- salt stress) in different varieties were screened; polymorphic SNP and SNPr (SNP related to salt tolerance) were obtained. Annotation and analysis of these SNPs showed that (1) the induction efficiency of salinity stress on SNPv of cotton materials with different salt tolerance index was different, in which the induction efficiency on salt-sensitive materials was significantly higher than that on salt-tolerant materials. The induction of salt stress on SNPv was obviously biased. (2) SNPv induced by salt stress may be related to the methylation changes under salt stress. (3) SNPr may influence salt tolerance of plants by affecting the expression of salt-tolerance related genes.

Inverse correlation between salt tolerance and host-adaptation in mycobacteria.

BackgroundThe genus Mycobacterium includes host-adapted organisms regarded as obligate and opportunistic pathogens and environmental organisms. Factors contributing to this wide range of adaptations are poorly known.ResultsWe studied the salt tolerance of 46 Mycobacterium species of medical interest. Representative strains of the Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium chelonae-abscessus complex, Mycobacterium ulcerans, Mycobacterium marinum, Mycobacterium lentiflavum, Mycobacterium fortuitum and Mycobacterium conceptionense were inoculated on Middlebrook 7H10 medium supplemented with 0–10 % sodium chloride. Colonies were counted after 2–4 week incubation at the appropriate 30–37 °C temperature depending on the tested strain. Further comparative genomics was done on 15 Mycobacterium strains representing the spectrum of salt-tolerance of mycobacteria. Based on the results the different species were grouped according to their salt tolerance into a “salt-sensitive” group (growth up to ≤3 % salt) containing the M. tuberculosis complex, Mycobacterium chelonae, Mycobacterium lentiflavum, Mycobacterium ulcerans and Mycobacterium marinum; a “salt-intermediate” group (growth between 4 and 6 % salt) comprising Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera and a “salt-resistant” group (growth up to >6 %) comprising Mycobacterium homonissuis, Mycobacterium bolettii, Mycobacterium fortuitum and Mycobacterium conceptionense. Genomic analysis revealed that 290 genes were unique to species belonging to the salt-sensitive group; and that 15 % were annotated as being functionally associated with the ESX secretion systems Pro-Glu and Pro–Pro-Glu family proteins.ConclusionsIn this work we found an inverse correlation between salt tolerance and host adaptation. We thus propose that salinity is one of the multiple factors determining the ecological niches of mycobacteria.

GENDER DIFFERENCES IN ANTIHYPERTENSIVE EFFICIENCY OF COMBINATION PHARMACOTHERAPY IN PATIENTS WITH RESISTANT HYPERTENSION AND ABDOMINAL OBESITY IN RELATION TO SALT SENSITIVITY

Objective. To estimate the effectiveness of combination antihypertensive therapy, including the direct renin inhibitor aliskiren, in resistant hypertension (RHTN) and abdominal obesity (AO) according to gender and salt sensitivity. Design and methods. The study included 161 patients with RHTN and AO, 78 (48.4 %) men and 83 (51.6 %) women. All patients at baseline and after 48 weeks of therapy as well as clinical and anthropometric study, electrocardiography and ambulatory blood pressure monitoring (ABPM) («Petr Telegin» BPLab Vasotens, Russia). Based on the V. I. Kharchenko’s test, all patients were divided into 4 groups: group 1 m (n = 38) and 1 w (n = 42) — «salt sensitive» men and women, and group 2 m (n = 40) and 2 w (n = 41) — «salt resistant» men and women. All patients received combination therapy: enalapril (renitek 20 mg/day, MSD, Switzerland), amlodipine (normodipin 10 mg/day, Gedeon Richter, Hungary), hydrochlorothiazide (hydrochlorothiazide 12.5 mg/day, Gedeon Richter, Hungary) and direct renin inhibitor aliskiren (rasilez 150 mg/day, Novartis, Switzerland). After 3 weeks, aliskiren dose was increased up to 300 mg/day in case of low efficiency, followed by the repeated evaluation 3 weeks later. The data were processed using nonparametric statistics (Statistica 6.1, StatSoft Inc, USA). results. After 6 weeks of antihypertensive therapy including aliskiren (daily dose of 150/300 mg), target blood pressure (BP) < 140/90 mm Hg was detected in 31 (81.6 %) men and 32 (76 %) women in salt sensitive group, and in 31 (77.5 %) men and 39 (95.1 %) women in salt resistant group. Target BP < 140/90 mm Hg was registered more frequently among salt resistant women compared to salt resistant men (p = 0.02) and salt sensitive women (p = 0.01). All treatment groups showed a significant decrease in office systolic (SBP) and diastolic BP (DBP), and heart rate. Regardless of salt sensitivity and gender, there was a significant positive changes of ABPM indicators after 48 weeks of treatment. However, in salt sensitive men and women, the change in ABPM parameters was comparable, while salt resistant women showed more marked changes in comparison with salt resistant men positive, including changes in 24-mean and daily values of SBP and DBP, SBP and DBP time index and variability during the day, as well as the time and the speed of morning surge in SBP and DBP. After 48 weeks of therapy, «dipper» BP profile was found in 17 (54.8 %) of 31 men and 17 (53.1 %) of 32 women in the salt sensitive group. In salt resistance group, «dipper» type was more prevalent among women than among men (51.3 and 35.5 %, respectively, p = 0.048). conclusions. Results of the study demonstrated a significant efficiency of aliskiren as part of combination antihypertensive therapy in both men and women with RHTN and AO regardless of salt sensitivity. At the same time, in salt sensitive men and women antihypertensive effects of aliskiren were comparable regardless of gender, whereas among salt resistant patients women showed higher benefit compared to men.

Renal Urotensin II System Plays Roles in the Regulation of Blood Pressure in Dahl Salt-Resistant Rat.

Introduction. Dahl salt-resistant (SR) animal models are similar to peritoneal dialysis patients with fluid volumes overload with normal blood pressure in hemodynamic profiles. We will verify the roles of UII in the regulation of blood pressure in these animal models. Methodology. The Dahl salt-sensitive (SS) and SR rats and UII receptor gene knocked out (KO) mice were placed on a high-salt diet. Renal tissues were performed for the expression of UII in Dahl groups. Results. After high-salt diet for 6 weeks, the systolic blood pressure (SBP) in SR group was significantly lower, accompanied with higher urinary UII levels, higher 24-hour urinary sodium excretion, and higher urinary creatinine clearance in the SR rats in comparison to SS group. The expressions of UII and UT were both upregulated in the kidney tissues of SR group in comparison to SS group (P < 0.05). After high-salt diet for 8 weeks, the SBP of the KO group is significantly higher than that of the wild type group. Conclusion. We first demonstrate that renal UII system can play important roles in the regulation of blood pressure in Dahl SR rats which can be highly correlated to its effect on renal tubular sodium absorption.

Effects of salt intake and potassium supplementation on renalase expression in the kidneys of Dahl salt-sensitive rats.

Renalase is currently the only known amine oxidase in the blood that can metabolize catecholamines and regulate sympathetic activity. High salt intake is associated with high blood pressure (BP), possibly through the modulation of renalase expression and secretion, whereas potassium can reverse the high salt-mediated increase in blood pressure. However, whether potassium could also modulate BP through renalase is unclear. In this study, we aim to investigate how salt intake and potassium supplementation affect the level of renalase in rats. Eighteen salt-sensitive (SS) and 18 SS-13BN rats were divided into six groups, receiving normal salt (0.3% NaCl), high salt (8% NaCl) and high salt/potassium (8% NaCl and 8% KCl) dietary intervention for four weeks. At the end of experiments, blood and kidneys were collected for analysis. mRNA level of renalase was measured by quantitative real-time PCR and protein level was determined by Western blot. We found that mRNA and protein levels of renalase in the kidneys of SS and SS-13BN rats were significantly decreased (P < 0.05) after high salt intervention, whereas dopamine in plasma was increased (P < 0.05) compared with rats received normal salt, suggesting that salt may induce salt-sensitive hypertension through inhibition of renalase expression. We also found increased mRNA level and protein level of renalase, decreased catecholamine levels in plasma, and decreased BP in SS rats treated with high salt/potassium, compared with that of the high salt SS group. Taken together, the salt-induced increase and potassium-induced decrease in BP could be mediated through renalase. More studies are needed to confirm our findings and understand the underlying mechanisms.

Clustering of Rice (Oryza sativa L.) Varieties Cultivated in Jaffna District of Sri Lanka based on Salt Tolerance during Germination and Seedling Stages

Twenty three rice ( Oryza sativa L. ) varieties cultivated in Jaffna district of Sri Lanka were screened for salt tolerance at the germination and early seedling stage using different salinity levels (0, 4, 8, 12, 24 and 45 dSm -1 ). Cluster analysis was done for germination energy, speed of germination, final germination percentage, root length, root dry weight, plumule length and plumule dry weight. All the tested variables, except sodium concentration in grains, decreased with increased salt levels and had significant differences (p -1 . The osmotic effect and toxic effect due to sodium, in combination, played a major role in germination of seeds and early seedling growth due to inhibitory effect in absorption of water. Among the cultivated rice varieties in Jaffna, Pachchaperumal, At 362, Bg 250, Bg 352, H4, Bg 304, Bg 360 and CO 10 have higher germination energy, speed of germination, final germination percentage, average root length, plumule length and low sodium concentration in grains and were categorized into high tolerant group. The rice varieties At 353 and Addakari were in the tolerant group. Varieties Morungan, Periavellai, At 308 and Moddaikarupan were grouped under the salt sensitive group whereas varieties At 402 and At 303 were in highly sensitive group to salt at 24 dSm -1 during their germination stage. Tropical Agricultural Research Vol. 25 (3): 358-375 (2014)

Ambulatory blood pressure and blood pressure load responses to low sodium intervention in Han Chinese population

We aimed to illustrate ambulatory blood pressure monitoring parameters responses to low sodium intake and their differences between salt-sensitive and non-salt-sensitive individuals. A total of 186 participants were included in this analysis. Twenty-four hour, day-time and night-time blood pressure (BP) and BP load decreased during low sodium intervention, especially in salt-sensitive (SS) group. After multivariable adjustment, 24-h systolic BP, diastolic BP, mean arterial pressure and BP load responses to low sodium intervention of SS individuals were more pronounced than those of non–salt-sensitive individuals. Thus, reducing salt intake is potentially needed for the prevention of hypertension, especially in SS individuals.Trial registration: ClinicalTrials.gov identifier: NCT00721721.

Abstract 072: Newly Developed Personal Device can Detect Changes and Variations of Urinary Na/K Ratio with Standardized Low- and High-salt Meals in Healthy Volunteers

Background: A low-sodium (Na), high-potassium (K) diet is recommended to suppress blood pressure elevation, but determining the absolute amounts of Na and K in a diet is difficult. A novel portable device was developed to allow easy measurement of urinary Na/K ratio on the spot. In this study, our aims were 1): to observe the changes of urinary Na/K ratio in subjects on low- and high-Na diet and 2): to determine if there are differences in urinary Na/K ratio between subjects with and without salt sensitivity. Methods: Healthy volunteers (14 subjects) ingested standardized low- (3 g NaCl /day) and high-Na (20 g NaCl/day) meals for 7 days each. Urinary Na/K ratio was measured at each voiding using a prototype device (Omron Healthcare). Collection of blood and 24-hour urine was conducted at the end of each diet period (unrestricted (NS), low-salt (LS), and high-salt (HS)). Those with mean blood pressure difference (LS vs. HS) ≥ 5% were determined as salt-sensitive (SS) and others salt-resistant (SR). Results: Urinary Na/K ratio reached a plateau approximately 3 days after each change in the Na level of the diet. Urinary Na/K ratio of spot urine correlated well with Na/K ratio of 24-hour urine. Average urinary Na/K ratio was 3.9 ± 1.9 on the last day of NS, 0.8 ± 0.3 on LS, and 6.9 ± 2.1 on HS. The variation of urinary Na/K ratio was small during the LS diet period. The change in urinary Na/K ratio of SS group tended to be slower than that of SR. This device may also be useful in diabetic and proteinuric patients as Na/K ratio was affected minimally by experimental glucose and protein addition. Conclusion: Using an easy-to-use device, measurements of urinary Na/K ratio keenly reflected the sodium level of the diet.

ASSA13-04-1 The Study of Acute Intravenous Saline Load Test Replacement Preoperative Hydration For Screening and Prevention of Contrast Induced Nephropathy

<h3>Background</h3> Contrast induced nephropathy (CIN) is the third most common cause of acquired acute kidney injury. People with blood pressure of salt sensitive (SS) has genetic kidney natriuresis defects. SS has gained increasing clinical attention because of the possible association of SS with the risk of developing cardiovascular and renal complications. Therefore, the SS more susceptible to CIN is worth of studying. Hydration is the earliest used, widely accepted and effective method to reduce CIN. Previous study showed that 0.9% NaCl is better than 0.45% NaCl in reducing CIN by intravenous hydration. What’s more, 1.0% NaCl saline load test in CIN prevention is worth of studying. <h3>Objective</h3> To identify the new risk factors of CIN and to prevent CIN by using acute intravenous saline load test instead of preoperative hydration. <h3>Methods</h3> Total 240 patients receiving CAG and/or PCI and belonging to medium- and high-risk according to the CIN risk scores were recruited. The simplified saline load test was done before operation in 160 patients. Conventional intravenous infusion total 9.0 ml/kg of 1.0% NaCl continued 8 hour’s time. Use the cuff method measuring blood pressure before and after the infusion, calculating the average blood pressure according to the formula = 1/3 systolic blood pressure +2/3 diastolic blood pressure, the average blood pressure after infusion higher than before ≥ 5mmHg is SS (SS group n = 88), otherwise is not salt sensitive (NS group, n = 72). The control group including 80 patients who has not received saline load test before operation (control group, n = 80). All patients in the three groups receive hydration with 0.9%NaCl continued 24 hour’s time. The heart function index (NT-proBNP), renal function index (Scr, BUN) at postoperative 24 h, 48 h, 72 h and the urinary NGAL at postoperative 2 h, 4 h, 6 h, 12 h, 24 h, 48 h, 72 h were collected and analysed. <h3>Results</h3> The incidence of CIN in the control group was significantly higher than that in SS group (17.50% vs 12.50%, p &lt; 0.01) and NS group (17.50% vs 1.38%, p &lt; 0.01). The incidence of CIN in the SS group was also significantly higher than that in the NS group (12.50% vs 1.38%, p &lt; 0.01). The heart function in the NS group after CAG and/or PCI was better than that in the NS group (p &lt; 0.05). But the time in hospital and the rate of adverse reaction during hospitalisation were no significant difference in the three groups (p &gt; 0.05). <h3>Conclusions</h3> SS could be one of new risk factors of CIN. The acute intravenous saline load test could replace preoperative hydration, screening and preventing the CIN.

Microvascular function is reduced in normotensive salt‐sensitive individuals independent of dietary sodium intake

Impairments in microvascular (MV) function are thought to occur early in cardiovascular disease development. We sought to determine if MV function is altered in salt‐sensitive (SS) adults compared to salt‐resistant (SR) adults during low (LS) and high (HS) sodium diets. Seven healthy SS adults and 7 healthy SR adults were studied (SS: 2M, 5F; 48±4 yrs; SR: 2M, 5F; 45±3 yrs). After a run‐in diet, subjects were randomized to a 7 day LS (20 mmol/d) and 7 day HS (300–350 mmol/d) diet (controlled feeding study). Salt sensitivity was defined as a &gt;; 5 mmHg change in 24‐hour mean arterial BP (MAP) from the LS to HS diet. MV function was assessed using laser Doppler flowmetry during local heating (42°C). Cutaneous vascular conductance (CVC) was calculated as red blood cell flux/MAP and all data were expressed as a percentage of the maximum CVC (28 mM SNP, 43°C). 24 hour MAP (mmHg) increased in the SS group between diets, but was unchanged in the SR group (SS: LS: 85±2, HS: 92±3, p&lt;0.05; SR: LS:83±3, HS: 83±2, p&gt;;0.05). Plateau %CVCmax was impaired in the SR group on the HS diet compared to the LS diet (80±2 vs. 90±2%; p&lt;0.05). There were no differences in plateau %CVCmax in the SS group between LS and HS diets (80±4 vs. 82±3%; p&gt;;0.05) but both were impaired (p&lt;0.05) compared to the SR group on the LS diet. These data suggest that MV function is impaired in SS adults independent of dietary sodium intake. Supported by 2 P20 RR016472‐11 &amp; R01 HL 104106.

Evolution of blood pressure from adolescents to youth in salt sensitivies: a 18-year follow-up study in Hanzhong children cohort.

BackgroundEssential hypertension mostly originates from children. Salt Sensitivity (SS) is regarded as the intermediate phenotype of essential hypertension. The present study investigated the effects of salt-sensitivity on evolution of blood pressure (BP) and development to hypertension from adolescents to youth.MethodsA baseline survey was carried out in 4,623 adolescents aged 6-15 years old in Hanzhong rural areas in 1987, 310 of whom(mean 9.2 years) were randomly recruited for determination of salt sensitivity using the tests of oral saline load and furosemide sodium-volume depletion. SS was diagnosed in 101 subjects while 209 were determined as non-salt-sensitive (NSS). We made a 18-year followed-up of the cohort in 2005.ResultsThe response rate for surviving baseline adolescents was 71.9%. At follow up, BP in youth with baseline SS was higher than that in NSS (SBP:122.9 ± 13.1 VS 117.3 ± 12.4, P < 0.01; DBP: 78.2 ± 10.4 VS 74.7 ± 10.8, P < 0.05). Longitudinal analysis of 18-year BP evolution, subjects in SS had greater Systolic BP change than subjects in NSS(19.6 ± 12.714.7 ± 12.2, P < 0.01). The incidence of hypertension in salt sensitive group was higher than that in NSS group (15.5% VS 6.3%, RR = 2.34, P < 0.05).ConclusionOur findings indicate that adolescents with higher BP salt-sensitivity have a higher rate of incident hypertension in youth. Salt sensitivity could be at high risk predisposing to development of hypertension from adolescents to youth.