Long-term burden and increasing trends of body mass index are linked with adult hypertension through triglyceride-glucose index: A 30-year prospective cohort study.

BACKGROUND AND AIMS: Insulin resistance (IR) has previously been associated with hypertension, and obesity is a risk factor for IR and hypertension. There is likely an association between body mass index (BMI) and risk for hypertension through the triglyceride-glucose (TyG) index but this relationship remains uncharacterized. METHODS AND RESULTS: This study is based on the Hanzhong Adolescent Hypertension Cohort, which is an ongoing prospective study established in 1987. The TyG index was calculated as ln [fasting triglyceride (mg/dl) × fasting plasma glucose (mg/dl)/2]. The total area under the curve (AUCt) and incremental AUC (AUCi) were calculated as the long-term burden and trend of BMI, respectively. We found that BMI AUCt and BMI AUCi were significantly associated with the risk of adult hypertension, both without (RR = 1.30/1.31 for BMI AUCt/AUCi) and with (RR = 1.25/1.26 for BMI AUCt/AUCi) the inclusion of the TyG index as a covariate. Importantly, mediation analysis revealed that the TyG index mediated the BMI AUCt-SBP association (19.3%), the BMI AUCt-DBP association (22.7%), the BMI AUCi-SBP association (18.5%) and the BMI AUCi-DBP association (21.3%). Furthermore, the TyG index had a significant mediating effect of 15.9% on the BMI AUCt-hypertension association and 14.9% on the BMI AUCi-hypertension association. CONCLUSION: These findings suggest that the TyG index plays an important mediating role in the association between the cumulative burden and increasing trends of BMI originating in childhood and the risk of hypertension in midlife. We emphasize that early weight management has the potential to reduce the burden of hypertension caused by IR. TRIAL REGISTRATION: The study was clinically registered at the ClinicalTrials.gov (NCT02734472) and approved by the Academic Committee of the First Affiliated Hospital of Xi'an Jiaotong University (XJTU1AF2015LSL-047).

Sex differences in impact of cumulative systolic blood pressure from childhood to adulthood on albuminuria in midlife: a 30-year prospective cohort study.

BACKGROUND AND OBJECTIVES: Albuminuria is recognized as being a predictor of cardiovascular and renal disease. We aimed to identify the impact of the long-term burden and trends of systolic blood pressure on albuminuria in midlife, as well as to explore sex differences concerning this relationship. METHODS: This longitudinal study consisted of 1,683 adults who had been examined 4 or more times for blood pressure starting in childhood, with a follow-up time period of 30 years. The cumulative effect and longitudinal trend of blood pressure were identified by using the area under the curve (AUC) of individual systolic blood pressure measurement with a growth curve random effects model. RESULTS: Over 30 years of follow-up, 190 people developed albuminuria, including 53.2% males and 46.8% females (aged 43.39 ± 3.13 years in the latest follow-up). The urine albumin-to-creatinine ratio (uACR) values increased as the total and incremental AUC values increased. Additionally, women had a higher albuminuria incidence in the higher SBP AUC groups than men do (13.3% for men vs. 33.7% for women). Logistic regression showed that the ORs of albuminuria for males and females in the high total AUC group were 1.34 (0.70-2.60) and 2.94 (1.50-5.74), respectively. Similar associations were found in the incremental AUC groups. CONCLUSIONS: Higher cumulative SBP was correlated with higher uACR levels and a risk of albuminuria in middle age, especially in women. The identification and control of cumulative SBP levels from an early age may assist in reducing the incidences of renal and cardiovascular disease for individuals in later life.

Association of Genetic Variants of Klotho with BP Responses to Dietary Sodium or Potassium Intervention and Long-Term BP Progression.

OBJECTIVES: Klotho (KL) plays pivotal roles in the progression of salt-sensitive hypertension. Salt-sensitive hypertension was associated with KL genotypes. We aimed to explore the association of common genetic variants of KL with individual blood pressure (BP) responses to sodium and potassium through a dietary intervention study as well as long-term BP progression. METHODS: We conducted family-based dietary interventions among 344 participants from 126 families in rural villages of northern China in 2004. Subjects sequentially underwent a baseline diet, a low-salt diet (51.3 mmol/day Na), a high-salt diet (307.8 mmol/day Na), and a high-salt + potassium supplementation diet (307.8 mmol/day Na + 60 mmol/day K). After dietary intervention, we followed up with these participants in 2009 and 2012. The associations between 6 single-nucleotide polymorphisms (SNPs) of KL and phenotypes were analyzed through a linear mixed-effects model. RESULTS: SNPs rs211247 and rs1207568 were positively correlated with the BP response to high-salt diet in the dominant model after adjusting for confounders (ß = 1.670 and 2.163, p = 0.032 and 0.005, respectively). BPs rs526906 and rs525014 were in a haplotype block. Block rs526906-rs525014 was positively correlated with diastolic BP response to potassium and potassium sensitivity in the additive model (ß = 0.845, p = 0.032). In addition, regression analysis indicated that rs211247 was associated with long-term systolic BP alterations after 8 years of follow-up in the recessive model (ß = 20.47, p = 0.032). CONCLUSIONS: Common variants of the KL gene might modify individual BP sensitivity to sodium or potassium and influence the long-term progression of BP, suggesting a potential role in the development of salt-sensitive hypertension. Thus, KL may be a new early intervention target for salt-sensitive hypertension.

Risk factors for electrocardiographic left ventricular hypertrophy in a young Chinese general population: the Hanzhong adolescent cohort study.

BACKGROUND: Electrocardiographic left ventricular hypertrophy (ECG-LVH) is a common manifestation of preclinical cardiovascular disease. The present study aimed to investigate risk factors for ECG-LVH and its prevalence in a cohort of young Chinese individuals. METHODS: (1) A total of 1515 participants aged 36-45 years old from our previously established cohort who were followed up in 2017 were included. Cross-sectional analysis was used to examine risk factors for ECG-LVH and its prevalence. (2) A total of 235 participants were recruited from the same cohort in 2013 and were followed up in 2017. Longitudinal analysis was used to determine the predictors of LVH occurrence over the 4-year period. We used multivariable logistic regression models to calculate OR and 95% CIs and to analyze risk factors for ECG-LVH. RESULTS: In the cross-sectional analysis, the prevalence of LVH diagnosed by the Cornell voltage-duration product in the overall population and the hypertensive population was 4.6% and 8.8%, respectively. The logistic regression results shown that female sex [2.611 (1.591-4.583)], hypertension [2.638 (1.449-4.803)], systolic blood pressure (SBP) [1.021 (1.007-1.035)], serum uric acid (SUA) [1.004 (1.001-1.006)] and carotid intima-media thickness (CIMT) [67.670 (13.352-342.976)] were significantly associated with the risk of LVH (all P < 0.05). In the longitudinal analysis, fasting glucose [1.377 (1.087-1.754)], SBP [1.046 (1.013-1.080)] and female sex [1.242 (1.069-1.853)] were independent predictors for the occurrence of LVH in the fourth year of follow-up. CONCLUSIONS: Our study suggested that female sex, hypertension, SBP, SUA and CIMT were significantly associated with the risk of LVH in young people. In addition, fasting glucose, SBP and female sex are independent predictors of the occurrence of LVH in a young Chinese general population.

Long-term burden of higher body mass index from childhood on adult cardiometabolic biomarkers: A 30-year cohort study.

BACKGROUND AND AIMS: Data are limited regarding the association between long-term burden of higher body mass index (BMI) from childhood and cardiometabolic biomarkers. METHODS AND RESULTS: A total of 1553 individuals aged 6-15 years, who were examined 4 or more times for BMI since childhood and followed for 30 years were included in our analysis. Total area under the curve (AUCt) and incremental AUC (AUCi) were calculated as the long-term burden and trends of BMI. Cardiometabolic biomarkers including serum uric acid (SUA), fasting blood-glucose (FBG), and triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) were obtained from venous blood samples. The results showed a positive association of BMI AUCt and AUCi with cardiometabolic biomarkers. After adjusting for demographic variables, the AUCt and AUCi of BMI were significantly associated with a higher level of SUA (ß = 3.71; 2.87), FBG (ß = 0.09; 0.09), and TG/HDL-C (ß = 0.14; 0.11). We performed further studies after dividing subjects into four groups according to AUCt and AUCi of BMI by quartiles. Compared with the lowest quartile group, the highest quartile group had significantly increased risk ratios of hyperuricemia (RR = 2.01; 1.74), type 2 diabetes mellitus (RR = 8.18; 3.96), and high-risk TG/HDL-C (RR = 4.05; 3.26). CONCLUSION: Our study identifies all subjects' BMI growth curve from childhood and indicates that the long-term burden of higher BMI significantly increases the cardiometabolic risk, and the impact of excessive body weight on cardiometabolic health originates in early life. We emphasize the importance of weight control from childhood for cardiometabolic health.

Predictive Role of Child-To-Adult Blood Pressure Trajectories for Incident Metabolic Syndrome: 30-Year Hanzhong Adolescent Hypertension Study.

OBJECTIVE: The relationship between child-to-adult blood pressure (BP) trajectories and metabolic syndrome (MetS) is unknown. We aimed to determine the predictive role of BP trajectories for incident MetS and its components. METHODS: The prospective Hanzhong Adolescent Hypertension study began in 1987 and included 2692 participants free of MetS at baseline with at least 3 BP measurements available from 1987 to 2017. RESULTS: The systolic BP (SBP) trajectory patterns were grouped as normal (class 1, 18.7%), high normal (class 2, 60.3%), prehypertensive (class 3, 13.1%), stage 1 hypertensive (class 4, 5.7%), and stage 2 hypertensive (class 5, 2.2%). Compared with those in the normal group, individuals in classes 2 to 5 had significantly higher risks of MetS (all Ps < .05), and those with hypertension had more than an 8-fold higher risk of MetS (both P < .05). The fully adjusted risk ratios (RRs) of central obesity increased significantly in a stepwise manner as the SBP trajectory group increased from class 1 to class 5 (P < .05). Compared with those with a normal SBP trajectory, participants in the prehypertensive group and stage 1 and stage 2 hypertensive groups had significantly higher RRs for high-risk triglycerides after full adjustment (RR = 1.89 [1.22-2.94]; RR = 3.61 [2.16-6.02]; and RR = 3.22 [1.52-6.84], respectively). CONCLUSION: Our study suggests that BP trajectories are predictive of incident MetS outcomes. Early detection of hypertension or modest elevations in BP is crucial. The stage of hypertension based on SBP level showed a greater association with central obesity.

Association of body mass index changes from childhood to adulthood with dyslipidemia in adults: Hanzhong adolescent cohort study.

BACKGROUND: Dyslipidemia is a disorder of lipid metabolism and associated with insulin resistance. The relationship between longitudinal body mass index (BMI) changes from childhood to adulthood and long-term dyslipidemia was explored in this study. METHODS: We assessed the longitudinal relationship between BMI changes since childhood and dyslipidemia among 1738 participants in rural areas of Hanzhong City, Shaanxi. All participants were initially examined between the ages of 6 and 15 years in 1987 and were reexamined in 1995, 2013 and 2017; the total follow-up duration was 30 years. Anthropometric measurements and blood biochemistry indexes were measured. RESULTS: We found that gradual progression of normal weight to overweight (OR = 1.65; 95% CI = 1.27, 2.15) or persistent overweight (OR = 2.45; 95% CI = 1.52, 3.96) from childhood to adulthood was associated with an increased risk of dyslipidemia in adulthood. And these risks were largely disappeared if the overweight or obesity during childhood was resolved by adulthood. The higher the BMI in adulthood and the younger the age at which overweight begins, the higher the risk of dyslipidemia. CONCLUSIONS: Early weight loss and any degree of weight loss from childhood to adulthood can help improve dyslipidemia in adulthood. We further emphasize the importance of weight management and control in public health primary prevention.

Body Mass Index Trajectories in Early Life Is Predictive of Cardiometabolic Risk.

OBJECTIVE: To identify distinct body mass index (BMI) trajectories across the life-course and explore the effects of BMI trajectories on the adult cardiovascular disease outcomes using a dataset with 30 years of follow-up in northern China. STUDY DESIGN: A total of 2839 participants aged 6-18 years whose BMIs were measured 3-6 times during the Hanzhong Adolescent Hypertension Study were included in our analysis. Latent mixture modeling was used to clarify distinct BMI trajectories in longitudinal analyses. RESULTS: Three groups with distinct trajectories in BMI were identified by the latent mixed models: a low-increasing group (n = 1324 [36.64%]), a moderate-increasing group (n = 1178 [16.89%]), and a high-increasing group (n = 337 [39.46%]). Compared with the participants in the low-increasing group, the risk ratios of hypertension, type 2 diabetes mellitus, high-risk triglycerides, and high-risk high-density lipoprotein cholesterol were more than 3.0 in the high-increasing group (all P < .001) after being fully adjusted. Increased risks existed in high brachial-ankle pulse wave velocity for the high-increasing group compared with the low-increasing group (RR, 2.75; 95% CI, 1.94-3.91; P < .001). Additionally, participants in the moderate-increasing group had a 2.31-fold increased risks of left ventricular hypertrophy (95% CI, 1.25-4.30; P = .008). CONCLUSIONS: Our study indicates that BMI trajectories from childhood to adulthood vary and that an elevated BMI trajectory in early life is predictive of an increased the risk of developing cardiovascular disease risks. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02734472.

LncRNA TNK2-AS1 regulated ox-LDL-stimulated HASMC proliferation and migration via modulating VEGFA and FGF1 expression by sponging miR-150-5p.

Long non-coding RNAs (lncRNAs) have been indicated for the regulatory roles in cardiovascular diseases. This study determined the expression of lncRNA TNK2 antisense RNA 1 (TNK2-AS1) in oxidized low-density lipoprotein (ox-LDL)-stimulated human aortic smooth muscle cells (HASMCs) and examined the mechanistic role of TNK2-AS1 in the proliferation and migration of HASMCs. Our results demonstrated that ox-LDL promoted HASMC proliferation and migration, and the enhanced proliferation and migration in ox-LDL-treated HASMCs were accompanied by the up-regulation of TNK2-AS1. In vitro functional studies showed that TNK2-AS1 knockdown suppressed cell proliferation and migration of ox-LDL-stimulated HASMCs, while TNK2-AS1 overexpression enhanced HASMC proliferation and migration. Additionally, TNK2-AS1 inversely regulated miR-150-5p expression via acting as a competing endogenous RNA (ceRNA), and the enhanced effects of TNK2-AS1 overexpression on HASMC proliferation and migration were attenuated by miR-150-5p overexpression. Moreover, miR-150-5p could target the 3' untranslated regions of vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 1 (FGF1) to regulate FGF1 and VEGFA expression in HASMCs, and the inhibitory effects of miR-150-5p overexpression in ox-LDL-stimulated HASMCs were attenuated by enforced expression of VEGFA and FGF1. Enforced expression of VEGFA and FGF1 also partially restored the suppressed cell proliferation and migration induced by TNK2-AS1 knockdown in ox-LDL-stimulated HASMCs, while the enhanced effects of TNK2-AS1 overexpression on HASMC proliferation and migration were attenuated by the knockdown of VEGFA and FGF1. Collectively, our findings showed that TNK2-AS1 exerted its action in ox-LDL-stimulated HASMCs via regulating VEGFA and FGF1 expression by acting as a ceRNA for miR-150-5p.

The Relationships of the Fractional Excretion of Uric Acid with Brachial-Ankle Pulse Wave Velocity and Ankle Brachial Index in Chinese Young Adults.

BACKGROUND/AIMS: Elevated serum uric acid (UA) was intimately correlated with vascular stiffness and abnormal ankle brachial index (ABI) in various populations. These correlations lost significance after adjustment for estimated glomerular filtration rate (eGFR), indicating that the association of UA and brachial-ankle pulse wave velocity (baPWV) or ABI might be driven by kidney function. UA is predominantly eliminated through the kidneys, and metabolic disorders can influence the clearance of UA. In this study, we aimed to explore the putative correlation between FEUA and baPWV or ABI to determine to what extent the associations with UA were affected by renal function. METHODS: This cross-sectional study enrolled 2351 participants, who underwent general health screening in Hanzhong people's hospital from March to June of 2017. BaPWV and ABI were measured using a volume-plethysmographic apparatus (BP-203RPEII; Nihon Colin, Tokyo, Japan). FEUA was divided into quartiles: Q1:FEUA≤3.07; Q2: 3.07 9.19. RESULTS: Lower FEUA predicted a higher prevalence of high baPWV and low ABI (p for trend <0.001). The respective ORs for high baPWV from the first to the third quartiles of FEUA were 1.777(1.323, 2.387); 1.561(1.158, 2.104); and 1.680 (1.250, 2.259). The prevalence of low ABI was greatly elevated with the decrement of FEUA [ORs for the first to third FEUA quartiles were 6.977(2.062, 23.610); 5.123(1.475, 17.790); and 2.685(0.709, 10.171), respectively]. The association of FEUA and ABI was independent of related confounding factors. However, the association between FEUA and baPWV was greatly influenced by corresponding confounders, especially gender. The efficacy of FEUA in the prediction of low ABI was stronger than that of serum UA. However, serum UA was more powerful in the prediction of high baPWV. CONCLUSION: Kidney function exerted a profound influence on the relationship between UA and baPWV or ABI, revealing complex interactions among cardiovascular risk factors.

Effect of Salt Intervention on Serum Levels of Fibroblast Growth Factor 23 (FGF23) in Chinese Adults: An Intervention Study.

BACKGROUND Fibroblast growth factor 23 (FGF23), a prominent regulator of phosphate and calcium metabolism, regulates sodium excretion in distal tubules through sodium-chloride cotransporter. This effect regulates blood pressure. Salt intake exerts effects on serum levels of FGF23 in mice. The aim of this study was to explore whether salt intervention affects serum concentrations of FGF23 in Chinese adults. MATERIAL AND METHODS We enrolled 44 participants from Lantian, a rural community of Shaanxi, China. All participants were maintained on a three-day normal diet, which was sequentially followed by a seven-day low-Na+ diet and seven-day high-Na+ diet. Serum FGF23 concentrations were assessed by ELISA. RESULTS Serum FGF23 concentrations elevated during low-salt diet compared with levels at baseline (66.20±44.21 pg/mL versus 86.77±53.74 pg/mL, p<0.05) and remarkably decreased when changed from low to high salt intake (86.77±53.74 pg/mL versus 49.26±42.67 pg/mL, p<0.001). Responses of FGF23 to salt intervention were more prominent in normotensive, older than 60 years, BMI <24 kg/m² and salt-resistant individuals. Furthermore, a significant inverse correlation was observed between 24-hour urinary sodium and serum concentrations of FGF23 after adjusting age, sex, BMI and hypertension status. CONCLUSIONS Dietary salt intervention significantly affects serum FGF23 in Chinese adults.

Extracellular renalase protects cells and organs by outside-in signalling.

Renalase was discovered as a protein synthesized by the kidney and secreted in blood where it circulates at a concentration of approximately 3-5 µg/ml. Initial reports suggested that it functioned as an NAD(P)H oxidase and could oxidize catecholamines. Administration of renalase lowers blood pressure and heart rate and also protects cells and organs against ischaemic and toxic injury. Although renalase's protective effect was initially ascribed to its oxidase properties, a paradigm shift in our understanding of the cellular actions of renalase is underway. We now understand that, independent of its enzymatic properties, renalase functions as a cytokine that provides protection to cells, tissues and organs by interacting with its receptor to activate protein kinase B, JAK/STAT, and the mitogen-activated protein kinase pathways. In addition, recent studies suggest that dysregulated renalase signalling may promote survival of several tumour cells due to its capacity to augment expression of growth-related genes. In this review, we focus on the cytoprotective actions of renalase and its capacity to sustain cancer cell growth and also the translational opportunities these findings represent for the development of novel therapeutic strategies for organ injury and cancer.

Effect of Salt Intake on Serum Glucagon-Like Peptide-1 Levels in Normotensive Salt-Sensitive Subjects.

BACKGROUND/AIMS: Excess dietary salt is a critical risk factor of salt-sensitive hypertension. Glucagon-like peptide-1 (GLP-1) , a gut incretin hormone, conferring benefits for blood pressure by natriuresis and diuresis. We implemented a randomized trial to verify the effect of altered salt intake on serum GLP-1 level in human beings. METHODS: The 38 subjects were recruited from a rural community of Northern China. All subjects were sequentially maintained a baseline diet period for 3 days, a low-salt diet period for 7 days (3.0g/day of NaCl) , and a high-salt diet period for additional 7 days (18.0g/day of NaCl). RESULTS: Serum GLP-1 level increased significantly with the change from the baseline period to the low-salt diet period and decreased with the change from the low-salt to high-salt diet in normotensive salt-sensitive (SS) but not salt-resistant (SR) individuals. There was a significant inverse correlation between the serum GLP-1 level and the MAP in SS subjects. Inverse correlation between the serum GLP-1 level and 24-h urinary sodium excretion was also found among different dietary interventions in SS subjects. CONCLUSIONS: Our study indicates that variations in dietary salt intake affect the serum GLP-1 level in normotensive salt-sensitive Chinese adults.

The Role of Uric Acid in Hypertension of Adolescents, Prehypertension and Salt Sensitivity of Blood Pressure.

Uric acid is the end product of purine metabolism. Metabolic disorders of uric acid are associated with many disease states. Substantial evidence suggests the possible role of uric acid as a mediator of high blood pressure. Elevated uric acid is closely associated with new onset essential hypertension in adolescents and prehypertension; and urate-lowering agents can significantly improve these early stages of hypertension. Uric acid also influences salt sensitivity of blood pressure through two phases. Local renin-angiotensin-aldosterone system activation initiates renal damage, arteriolopathy, and endothelium dysfunction, which is followed by the dysregulation of sodium homeostasis, thereby leading to increased salt sensitivity. In this review we summarize the available evidence to contribute to a better understanding of the casual relationship between uric acid and early or intermediate stages of hypertension. We hope our review can contribute to the prevention of hypertension or provide new insights into a treatment that would slow the progression of hypertension.

Effects of Salt Loading on Plasma Osteoprotegerin Levels and Protective Role of Potassium Supplement in Normotensive Subjects.

BACKGROUND: Excess dietary salt is strongly correlated with cardiovascular disease, morbidity, and mortality. Conversely, potassium likely elicits favorable effects on cardiovascular disorders. In epidemiological studies, increased plasma osteoprotegerin (OPG) concentrations are associated with atherosclerosis and vascular deaths. Our study was designed to examine the effects of salt intake and potassium supplementation on plasma OPG levels in normotensive subjects.Methods and Results:The 18 normotensive subjects were selected from a rural community in China. They were sequentially maintained on low-salt diet for 7 days (3 g/day, NaCl), high-salt diet for 7 days (18 g/day), and high-salt diet with potassium supplementation for 7 days (18 g/day of NaCl+4.5 g/day of KCl). High-salt intake enhanced plasma OPG levels (252.7±13.9 vs. 293.4±16.1 pg/mL). This phenomenon was abolished through potassium supplementation (293.4±16.1 vs. 235.1±11.3 pg/mL). Further analyses revealed that the OPG concentration positively correlated with 24-h urinary sodium excretion (r=0.497, P<0.01). By contrast, OPG concentration negatively correlated with 24-h urinary potassium excretion (r=0.594, P<0.01). CONCLUSIONS: Salt loading can enhance the production of circulating OPG. Potassium supplementation can reverse the effects of excessive OPG. Our study results may improve our understanding of the roles of salt and potassium in the risk of cardiovascular disorders.

Plasma Renalase is Not Associated with Blood Pressure and Brachial-Ankle Pulse Wave Velocity in Chinese Adults With Normal Renal Function.

BACKGROUND/AIMS: This study aimed to investigate the association of renalase with blood pressure (BP) and brachial-ankle pulse wave velocity (baPWV) in order to better understand the role of renalase in the pathogenesis of hypertension and atherosclerosis. METHODS: A total of 344 subjects with normal kidney function were recruited from our previously established cohort in Shaanxi Province, China. They were divided into the normotensive (NT) and hypertensive (HT) groups or high baPWV and normal baPWV on the basis of BP levels or baPWV measured with an automatic waveform analyzer. Plasma renalase was determined through an enzyme-linked immunosorbent assay. RESULTS: Plasma renalase did not significantly differ between HT and NT groups (3.71 ± 0.69 µg/mL vs. 3.72 ± 0.73 µg/mL, P = 0.905) and between subjects with and without high baPWV (3.67 ± 0.66 µg/mL vs. 3.73 ± 0.74 µg/mL, P = 0.505). However, baPWV was significantly higher in the HT group than in the NT group (1460.4 ± 236.7 vs. 1240.7 ± 174.5 cm/s, P < 0.001). Plasma renalase was not correlated with BP levels and baPWV in the entire group. Linear and logistic regression analysis revealed that plasma renalase was not significantly associated with hypertension and high baPWV. CONCLUSION: Plasma renalase may not be associated with BP and baPWV in Chinese subjects with normal renal function.

High Salt Diet Affects Renal Sodium Excretion and ERRα Expression.

Kidneys regulate the balance of water and sodium and therefore are related to blood pressure. It is unclear whether estrogen-related receptor α (ERRα), an orphan nuclear receptor and transcription factor highly expressed in kidneys, affects the reabsorption of water and sodium. The aim of this study was to determine whether changes in the expressions of ERRα, Na⁺/K⁺-ATPase and epithelial sodium channel (ENaC) proteins affected the reabsorption of water and sodium in kidneys of Dahl salt-sensitive (DS) rats. SS.13BN rats, 98% homologous to the DS rats, were used as a normotensive control group. The 24 h urinary sodium excretion of the DS and SS.13BN rats increased after the 6-week high salt diet intervention, while sodium excretion was increased in DS rats with daidzein (agonist of ERRα) treatment. ERRα expression was decreased, while ß- and γ-ENaC mRNA expressions were increased upon high sodium diet treatment in the DS rats. In the chromatin immunoprecipitation (CHIP) assay, positive PCR signals were obtained in samples treated with anti-ERRα antibody. The transcriptional activity of ERRα was decreased upon high salt diet intervention. ERRα reduced the expressions of ß- and γ-ENaC by binding to the ENaC promoter, thereby increased Na+ reabsorption. Therefore, ERRα might be one of the factors causing salt-sensitive hypertension.

Effect of salt intake and potassium supplementation on urinary renalase and serum dopamine levels in Chinese adults.

OBJECTIVE: The aim of our study was to assess the effects of altered salt and potassium intake on urinary renalase and serum dopamine levels in humans. METHODS: Forty-two subjects (28­65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day of NaCl), a high-salt diet for an additional 7 days (18.0 g/day of NaCl), and a high-salt diet with potassium supplementation for a final 7 days (18.0 g/day of NaCl + 4.5 g/day of KCl). RESULTS: Urinary renalase excretions were significantly higher during the high-salt diet intervention than during the low-salt diet. During high-potassium intake, urinary renalase excretions were not significantly different from the high-salt diet, whereas they were significantly higher than the low-salt levels. Serum dopamine levels exhibited similar trends across the interventions. Additionally, a significant positive relationship was observed between the urine renalase and serum dopamine among the different dietary interventions. Also, 24-hour urinary sodium excretion positively correlated with urine renalase and serum dopamine in the whole population. CONCLUSIONS: The present study indicates that dietary salt intake and potassium supplementation increase urinary renalase and serum dopamine levels in Chinese subjects.

Common Variants in Serum/Glucocorticoid Regulated Kinase 1 (SGK1) and Blood Pressure Responses to Dietary Sodium or Potassium Interventions: A family-Based Association Study.

BACKGROUND/AIMS: Serum/Glucocorticoid Regulated Kinase 1 (SGK1) plays a significant role in regulating renal Na(+) reabsorption, K(+) secretion, and blood pressure (BP). This study aimed to assess the association of common genetic variants in the SGK1 gene with BP responses to controlled dietary sodium or potassium interventions. METHODS: A total of 334 subjects from 124 families were recruited from the rural areas of northern China. After a three-day baseline observation, they were sequentially maintained a seven-day low-sodium diet (3g/day of NaCl or 51.3 mmol/day of sodium), a seven-day high-sodium diet (18 g/day of NaCl or 307.8 mmol/day of sodium) and a seven-day high-sodium plus potassium supplementation intervention (4.5 g/day of KCl or 60 mmol/day of potassium). Six single-nucleotide polymorphisms (SNPs) in the SGK1 gene were selected. RESULTS: After adjustment for multiple testing, SNP rs9376026 was significantly associated with diastolic BP (DBP) and mean arterial pressure (MAP) responses to low-sodium intervention (P = 0.018 and 0.022, respectively). However, the associations between selected SNPs in the SGK1 gene and BP responses to high-sodium or high-sodium plus potassium-supplementation intervention did not reach statistical significance. In addition, SNP rs9389154 and two other SNPs (rs1763509 and rs9376026) were associated respectively with systolic BP (SBP) and DBP at baseline (P = 0.040, 0.032, and 0.031, respectively). SNP rs3813344 was significantly associated with SBP, DBP, and MAP (P = 0.049, 0.015 and 0.018, respectively). CONCLUSION: Our study indicates that the genetic polymorphism in the SGK1 gene is significantly associated with BP responses to dietary sodium intervention.