Elevated serum uric acid is associated with angiotensinogen in obese patients with untreated hypertension

Isolated Nocturnal Hypertension in People Living With Human Immunodeficiency Virus: A Cross-Sectional Study

BACKGROUND

Nocturnal hypertension (NH) is a potent cardiovascular risk factor described frequently in people with HIV (PWH). Isolated NH (INH) is less well reported in PWH because of the need for ambulatory blood pressure monitoring (ABPM) in office normotensive patients. We aim to document the prevalence of NH and INH and the clinical factors associated with these phenotypes.

METHODS

Cross-sectional study from an HIV program in Argentina. Office and ABPM measurements, as well as clinical and laboratory exploration, were performed. We defined INH as NH with daytime normotension in patients with office normotension.

RESULTS

We obtained ABPM in 66 PWH, 60% male, aged 44.7 (IQR 27-69) years; 87% receiving antiretroviral therapy, and 86.2% virologically suppressed. ABPM-based hypertension prevalence was 54.7% (95% CI: 42.5-66.3). The prevalence of NH was 48.5% (32/66), while the INH prevalence was 19.7% (95% CI: 11.7-30.9). No differences were found regarding sex, HIV viral load, CD4+ T lymphocytes count, or years of infection between normotensive and INH patients. Multiple linear regression model adjusted for sex and age determined that body mass index (β = 0.93, P < 0.01), plasma uric acid (β = 0.25, P = 0.04), plasma potassium (β = -10.1, P = 0.01), and high-sensitivity C-reactive protein (hs-CRP) (β = 0.78, P = 0.02) independently predicted nocturnal systolic blood pressure (BP) in PWH. In a multiple logistic regression model adjusted for age and sex, the presence of sedentariness, plasma potassium <4 mEq/L, BMI, and hs-CRP levels were predictors of INH.

CONCLUSION

INH is highly prevalent in PWH. Metabolic and inflammatory markers predict nocturnal SBP in PWH.

Uric acid mediated the relationship between obesity and hypertension in children and adolescents: A population‑based cohort study

BACKGROUND AND AIM

Obesity and hyperuricemia (HUA) often coexist and have been widely accepted as risk factors for hypertension, but the role of uric acid (UA) in the relationship between obesity and hypertension remains unknown in children and adolescents.

METHODS AND RESULTS

A total of 7525 subjects aged 6-16 years were from the School-based Cardiovascular and Bone Health Promotion Program (SCVBH) at baseline (2017) and followed up in 2019. Multivariable logistic regression with interaction terms, cross-lagged panel analysis, and causal mediation model were applied to delineate the joint impact of obesity and HUA on hypertension, including the interaction effect, the temporal association, and the mediating effect of UA in the relationship between obesity and hypertension. There were 10.8 % of the participants with normotension at baseline developed hypertension after two years of follow-up. Cross-lagged panel analysis showed that the two-time point association was significant only from baseline BMI to follow-up UA (β1 = 0.302, P < 0.001), but not from baseline UA to follow-up BMI (β2 = 0.002, P = 0.745). Multivariable logistic regression showed that both obesity and HUA increased the risk of hypertension, but no interaction effect between HUA and obesity. The causal mediation analysis found that UA partially mediated the association between BMI and SBP (mediate proportion: 20.3 %, 95 % CI: 17.4-22.9 %) or DBP (mediate proportion: 11.9 %, 95 % CI: 3.9-18.2 %). The results were consistent in the analysis of systolic hypertension rather than diastolic hypertension.

CONCLUSIONS

It is mediating effect that UA played in the progress from obesity to hypertension, particularly systolic hypertension in children and adolescents.

Severe Hypouricemia Impairs Endothelium-Dependent Vasodilatation and Reduces Blood Pressure in Healthy Young Men: A Randomized, Placebo-Controlled, and Crossover Study

Background

Uric acid (UA) is a plasmatic antioxidant that has possible effects on blood pressure. The effects of UA on endothelial function are unclear. We hypothesize that endothelial function is not impaired unless significant UA depletion is achieved through selective xanthine oxidase inhibition with febuxostat and recombinant uricase (rasburicase).

Methods and Results

Microvascular hyperemia, induced by iontophoresis of acetylcholine and sodium nitroprusside, and heating‐induced local hyperemia after iontophoresis of saline and a specific nitric oxide synthase inhibitor were assessed by laser Doppler imaging. Blood pressure and renin‐angiotensin system markers were measured, and arterial stiffness was assessed. CRP (C‐reactive protein), allantoin, chlorotyrosine/tyrosine ratio, homocitrulline/lysine ratio, myeloperoxidase activity, malondialdehyde, and interleukin‐8 were used to characterize inflammation and oxidative stress. Seventeen young healthy men were enrolled in a randomized, double‐blind, placebo‐controlled, 3‐way crossover study. The 3 compared conditions were placebo, febuxostat alone, and febuxostat together with rasburicase. The allantoin (μmol/L)/UA (μmol/L) ratio differed between sessions (P<0.0001). During the febuxostat‐rasburicase session, heating‐induced hyperemia became altered in the presence of nitric oxide synthase inhibition; and systolic blood pressure, angiotensin II, and myeloperoxidase activity decreased (P≤0.03 versus febuxostat). The aldosterone concentration decreased in the febuxostat‐rasburicase group (P=0.01). Malondialdehyde increased when UA concentration decreased (both P<0.01 for febuxostat and febuxostat‐rasburicase versus placebo). Other parameters remained unchanged.

Conclusions

A large and short‐term decrease in UA in humans alters heat‐induced endothelium‐dependent microvascular vasodilation, slightly reduces systolic blood pressure through renin‐angiotensin system activity reduction, and markedly reduces myeloperoxidase activity when compared with moderate UA reduction. A moderate or severe hypouricemia leads to an increase in lipid peroxidation through loss of antioxidant capacity of plasma.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03395977.

What is the most important determinant of cardiometabolic risk in 60-65-year-old subjects: physical activity-related behaviours, overall energy expenditure or occupational status? A cross-sectional study in three populations with different employment status in Poland

OBJECTIVES

The aim of the study was to determine whether cardiovascular risk factors may differ according to occupational status and whether physical activity related to total energy expenditure (PA-EE) and related to health-related behaviours (PA-HRB) is associated with common cardiovascular risk factors or metabolic syndrome in pre-elderly subjects.

METHODS

Three hundred subjects aged 60-65 were recruited and divided into three equal groups of white-collar, blue-collar workers and unemployed subjects; 50% were women. The subjects were tested for major cardiovascular risk factors such as smoking, anthropometric indices, blood pressure, lipid levels, glucose, uric acid and homocysteine. PA-EE and PA-HRB were assessed with PA questionnaires.

RESULTS

Blue-collar workers displayed higher anthropometric indices, blood pressure and higher PA-EE in comparison with other two groups. PA-HRB had a positive impact on body mass indices, lipids, glucose, uric acid and the prevalence of metabolic syndrome, with no such relationship observed for PA-EE.

CONCLUSIONS

The greatest cardiovascular risk was observed in the blue-collar workers group. Only PA-HRB had a positive association with cardiometabolic risk profile. No relationship was observed for PA-EE. Thus, promoting everyday life and leisure time PA behaviours is crucial for preventing cardiometabolic risk in pre-elderly subjects, even in blue-collar workers with high work-related EE.

TLR2 and TLR4 mediate an activation of adipose tissue renin-angiotensin system induced by uric acid

Both hyperuricemia and adipose tissue renin-angiotensin system (RAS) are closely associated with multiple metabolic and cardiovascular diseases. We previously reported that uric acid could upregulate tissue RAS in adipocytes. In the present study, we aimed to reveal the involvement of toll-like receptors (TLRs) in uric acid-induced RAS activation in adipose tissue. A hyperuricemia rat model fed with a high-fructose diet and rat primary adipocytes were used in this study. Here, we inhibited TLR2 and TLR4 expression in adipose tissue and cultured adipocytes using small interfering RNA (siRNA). We found that high fructose-fed rats had hyperuricemia, higher body weight and greater adipose tissue content. We also found that hyperuricemia rats had raising blood pressure, higher expression levels of inflammatory cytokines and RAS components in adipose tissue, which could be prevented by TLR2/4-siRNA infection. In vitro study, uric acid caused a dose- and time-dependent increase in the mRNA expression of TLR2 and TLR4 in rat adipocytes. Uric acid could increase inflammatory cytokines and upregulate tissue RAS in rat adipocytes, which were both blocked with TLR2/4-siRNA infection. TNF-α and IL-6 could also result in an activation of tissue RAS expression in adipocytes. In conclusion, TLR2/4 mediated adipose inflammation plays a key role in RAS activation induced by uric acid in adipose tissue.

Prevalence of hyperuricemia and the relationship between serum uric acid and obesity: A study on Bangladeshi adults

Background and objectives

Recent studies have shown that hyperuricemia is commonly associated with dyslipidemia, cardiovascular diseases, hypertension and metabolic syndrome. Elevated serum uric acid has been demonstrated to be associated with obesity in the adult population in many countries; however, there is still a lack of evidence for the Bangladeshi population. The aims of this study were to evaluate the prevalence of hyperuricemia and determine the relationship between serum uric acid (SUA) and obesity among the Bangladeshi adults.

Methods

In this cross-sectional study, blood samples were collected from 260 adults (142 males and 118 females) and analyzed for SUA and lipid profile. All participants were categorized as underweight (n = 11), normal (n = 66), overweight (n = 120) and obese (n = 63) according to the body mass index (BMI) scale for the Asian population. Based on SUA concentration the participants were stratified into four quartiles (Q1: < 232 μmol/L, Q2: 232–291 μmol/L, Q3: 292–345 μmol/L and Q4: > 345 μmol/L).

Results

The mean age and BMI of the participants were 32.5 ± 13.3 years and 24.9 ± 3.8 kg/m², respectively. The average level of SUA was 294 ± 90 μmol/L with a significant difference between males and females (p < 0.001). Overall, the estimated prevalence of hyperuricemia was 9.3% with 8.4% in male and 10.2% in female participants. There were significant increases in the prevalence of obesity (17.4%, 22.2%, 28.6% and 31.8%, respectively, p < 0.01 for trend) across the SUA quartiles. A multiple logistic regression analysis revealed that SUA quartiles were independently associated with the presence of obesity (p < 0.01).

Conclusion

Present study indicates a significant positive relationship between SUA and obesity among the Bangladeshi adults. Therefore, routine measurement of SUA is recommended in obese individuals to prevent hyperuricemia and its related complications.

A comparative research on obesity hypertension by the comparisons and associations between waist circumference, body mass index with systolic and diastolic blood pressure, and the clinical laboratory data between four special Chinese adult groups

BACKGROUND

The obesity-hypertension pathogenesis is complex. From the phenotype to molecular mechanism, there is a long way to clarify the mechanism. To explore the association between obesity and hypertension, we correlate the phenotypes such as the waist circumference (WC), body mass index (BMI), systolic blood pressure (SB), and diastolic blood pressure (DB) with the clinical laboratory data between four specific Chinese adult physical examination groups (newly diagnosed untreated just-obesity group, newly diagnosed untreated obesity-hypertension group, newly diagnosed untreated just-hypertension group, and normal healthy group), and the results may show something.

OBJECTIVE

To explore the mechanisms from obesity to hypertension by analyzing the correlations and differences between WC, BMI, SB, DB, and other clinical laboratory data indices in four specific Chinese adult physical examination groups.

METHODS

This cross-sectional study was conducted from September 2012 to July 2014, and 153 adult subjects, 34 women and 119 men, from 21 to 69 years, were taken from four characteristic Chinese adult physical examination groups (newly diagnosed untreated just-obesity group, newly diagnosed untreated obesity-hypertension group, newly diagnosed untreated just-hypertension group, and normal healthy group). The study was approved by the ethics committee of Hangzhou Center for Disease Control and Prevention. WC, BMI, SB, DB, and other clinical laboratory data were collected and analyzed by SPSS.

RESULTS

Serum levels of albumin (ALB)，alanine aminotransferase (ALT), low density lipoprotein cholesterol (LDLC), triglyceride (TG), high density lipoprotein cholesterol (HDLC), alkaline phosphatase (ALP), uric acid (Ua), and TC/HDLC (odds ratio) were statistically significantly different between the four groups. WC statistically significantly positively correlated with BMI, ALT, Ua, and serum levels of glucose (GLU), and TC/HDLC, and negatively with ALB, HDLC, and serum levels of conjugated bilirubin (CB). BMI was statistically significantly positively related to ALT, Ua, LDLC, WC, and TC/HDLC, and negatively to ALB, HDLC, and CB. DB statistically significantly positively correlated with ALP, BMI, and WC. SB was statistically significantly positively related to LDLC, GLU, serum levels of fructosamine (FA), serum levels of the total protein (TC), BMI, and WC.

CONCLUSION

The negative body effects of obesity are comprehensive. Obesity may lead to hypertension through multiple ways by different percents. GGT, serum levels of gamma glutamyltransferase; ALB, serum levels of albumin; ALT, serum levels of alanine aminotransferase; LDLC, serum levels of low density lipoprotein cholesterol; TG, serum levels of triglyceride; HDLC, serum levels of high density lipoprotein cholesterol; FA, serum levels of fructosamine; S.C.R, serum levels of creatinine; IB, serum levels of indirect bilirubin; ALP, serum levels of alkaline phosphatase; CB, serum levels of conjugated bilirubin; UREA, Urea; Ua, serum levels of uric acid; GLU, serum levels of glucose; TC, serum levels of the total cholesterol; TB, serum levels of the total bilirubin; TP, serum levels of the total protein; TC/HDLC, TC/HDLC ratio.

Effect of Febuxostat, a Xanthine Oxidase Inhibitor, on Cardiovascular Risk in Hyperuricemic Patients with Hypertension: A Prospective, Open-label, Pilot Study

BACKGROUND AND OBJECTIVE

There is growing evidence of an association between high uric acid (UA) levels and cardiovascular disease (CVD). We hypothesized that febuxostat, a xanthine oxidase inhibitor, may be associated with suppressing the renin-angiotensin-aldosterone system (RAAS) and improving renal function in hyperurecemic patients with hypertension.

METHODS

We conducted a 6-month prospective study in which we randomized hypertensive hyperuricemic patients to either a febuxostat group (n = 30) or a control group (n = 30). The dose of febuxostat was adjusted to maintain the serum UA level at <6.0 mg/dL.

RESULTS

In the febuxostat group, the plasma renin activity (PRA), plasma aldosterone concentration (PAC), and serum UA level significantly decreased by 33 % (p = 0.0012), 14 % (p = 0.001), and 29 % (p < 0.0001), respectively. The estimated glomerular filtration rate (eGFR) significantly increased by 5.5 % (p = 0.001). Similar changes were not observed in the control group. Furthermore, a significant correlation was observed between the percent changes in the serum UA levels and the percent changes in the PRA (r = 0.277, p = 0.033), PAC (r = 0.310, p = 0.016), serum blood urea nitrogen levels (r = 0.434, p = 0.0005), serum creatinine levels (r = 0.413, p = 0.002), and eGFR (r = -0.474, p = 0.0001).

CONCLUSIONS

These results support the hypothesis that febuxostat might not only reduce serum UA levels but also suppress RAAS and improve renal function in hyperuricemic patients with hypertension, possibly leading to prevention of CVD.

Association between uric acid and renal function in hypertensive patients: which role for systemic vascular involvement?

The role of systemic vascular involvement in mediating the association between serum uric acid (SUA) and renal function in hypertension has not been explored. Main purpose of our study was to investigate whether morphofunctional vascular changes, assessed as carotid intima-media thickness (cIMT) and aortic pulse wave velocity (aPWV), might mediate the association between SUA and renal damage. We enrolled 523 hypertensive subjects with or without chronic kidney disease and divided population into tertiles of SUA based on sex-specific cutoff values. cIMT and aPWV were higher in uppermost SUA-tertile patients when compared to those in the lowest ones (all P < .001). Uricemia strongly correlated with cIMT and aPWV at univariate analysis (P < .001) and with cIMT after adjustment for confounders (P < .001). Adjustment for cIMT attenuated the relationship between SUA and estimated glomerular filtration rate (P = .019). Systemic vascular changes seem partially to mediate the association between SUA and renal function in hypertensive patients, regardless of kidney function.

Overweight modifies the longitudinal association between uric acid and some components of the metabolic syndrome: The Tromsø Study

BACKGROUND

Elevated uric acid (UA) is associated with the presence of the metabolic syndrome (MetS). In a prospective cohort study, we assessed whether baseline and longitudinal change in UA were risk factors for development of MetS and its individual components.

METHODS

We included 3087 women and 2996 men who had UA measured in the population based Tromsø Study 1994-95. The participants were stratified according to body mass index (BMI). Endpoints were MetS and each component of the syndrome after 7 years, according to the revised National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) definition.

RESULTS

Multiple logistic regression analyses showed that higher baseline UA was associated with higher odds of developing elevated blood pressure in overweight subjects (BMI ≥ 25 kg/m(2), odds ratio [OR] per 59 μmol/L UA increase 1.44, 95 % confidence interval [CI] = 1.17-1.77, P = 0.001), but not in normal-weight subjects (BMI < 25 kg/m(2), P for interaction = 0.04). Overweight also modified the association between baseline UA and the development of elevated fasting glucose (P for interaction = 0.01). UA was a predictor of MetS in all subjects (OR per 59 μmol/L UA increase 1.29, 95 % CI 1.18-1.41, P < 0.001). Furthermore, longitudinal UA change was independently associated with the development of MetS in all subjects (OR per 59 μmol/L UA increase over 7 years 1.28, 95 % CI 1.16-1.42, P < 0.001).

CONCLUSION

Increased levels of baseline UA independently predicted development of elevated blood pressure and higher fasting glycemia in the overweight, but not the normal-weight subjects. Baseline UA and longitudinal increase in UA over 7 years was associated with the development of MetS in all subjects. Whether increased UA should be treated differently in normal-weight and overweight persons needs further study.

Preterm Birth Is Associated with Higher Uric Acid Levels in Adolescents

OBJECTIVE

To compare serum uric acid levels in adolescents born prematurely and adolescents born at term and to assess the correlation between serum uric acid and blood pressure (BP) in those born prematurely.

STUDY DESIGN

In this observational cohort study, 124 adolescents born prematurely and 44 adolescents born at term were studied at 14 years of age. Multivariate analyses were used to describe the relationship of premature birth to serum uric acid while adjusting for confounding variables. Pearson correlation was used to describe the relationship between uric acid and systolic BP among those born prematurely.

RESULTS

Adjusting for race, sex, maternal hypertension, and fetal growth, we found that preterm adolescents had greater serum uric acid levels than adolescents born at term (adjusted mean difference 0.46, 95% CI 0.10-0.81 mg/dL; 27.4, 6-48.2 μmol/L; P = .012). Among those born prematurely, uric acid was positively correlated with systolic BP (Pearson correlation coefficient: 0.29, 0.12-0.44; P = .0013).

CONCLUSIONS

Serum uric acid levels are greater in adolescents born prematurely than in those born at term, and this difference could contribute to greater BP among individuals born prematurely.

Serum Uric Acid, Gender, and Low Ankle Brachial Index in Adults With High Cardiovascular Risk

Uric acid (UA) has been reported to be associated with cardiovascular disease (CVD) in caucasians. However, it is unclear whether this association remains significant in a Chinese population. The present study aimed to investigate the association between UA and low ankle brachial index (ABI), a measurement of peripheral arterial disease, in Chinese patients. A total of 6262 hospital-based patients with high CVD risk were enrolled. Low ABI was defined as ABI ≤0.9 in either side. Low ABI was detected in 1390 (22.2%) patients. Higher UA was significantly associated with higher risk of low ABI and modified by gender (P = .0045). After adjusting for age, body mass index, total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, fasting glucose, hypertension, and smoking, participants in the highest quartile of UA exhibited 37% (odds ratio [OR]:1.37, 95% confidence interval [CI]: 1.03-1.82) higher risk of low ABI compared to those in the lowest quartile in men, while OR (95% CI) was 1.69 (1.29-2.22) for women. However, when kidney function was further adjusted, the associations were attenuated in both men and women and were significant only in women. The results were suggestive of higher UA associating with higher risk of low ABI in women, and the association was largely driven by kidney function, especially in men.