Longitudinal Association Between Serum Uric Acid and Arterial Stiffness: Results From the Baltimore Longitudinal Study of Aging

The impact of serum acid, arterial stiffness, and hypertension as a mediating factor: A cohort study

BACKGROUND

Serum uric acid (SUA) has been associated with arterial stiffness. However, previous studies were limited to contradicting cross-sectional studies. This study aimed to examine the longitudinal association between SUA and the progression of arterial stiffness and the potential mechanisms.

METHODS

Based on the Kailuan study, arterial stiffness progression was assessed by the annual growth rate of repeatedly measured brachial-ankle pulse wave velocity (baPWV). Generalized linear regression models were used to estimate the association of SUA with baseline arterial stiffness (n = 37,659) and arterial stiffness progression (n = 16,506), and Cox regressions were used to investigate the risk of incident arterial stiffness (n = 13,843). Mediation analysis was used to explore the potential mediators of the associations.

RESULTS

Per standard deviation increase in SUA was associated with an 11.89 cm/s increment (95% confidence interval [CI], 8.60-15.17) in baseline baPWV and a 2.67 cm/s/yr increment in the annual growth rate of baPWV. During the 5.77-year follow-up, there were 1953 cases of incident arterial stiffness. Participants in the highest quartile of SUA had a 39% higher risk of arterial stiffness (HR, 1.39; 95% CI, 1.21-1.60), as compared with those in the lowest quartile of SUA. Furthermore, the observed associations were more pronounced in women than in men (Pint<0.05). The pathological pathway from high SUA to arterial stiffness was mainly mediated through hypertension (mediated proportion: 24.74%).

CONCLUSIONS

Our study indicates that SUA was positively associated with the risk of arterial stiffness and its progression, especially in women. The association was mainly mediated through hypertension.

Relationship Between Serum Uric Acid and Carotid Plaque in Patients With Coronary Artery Disease by Sex and Blood Pressure Status

The purpose of this study was to explore the sex difference and effects of blood pressure (BP) on the relationship between serum uric acid (SUA) and carotid plaque in patients with coronary heart disease (CHD). This large multicenter retrospective study included 12099 patients with CHD (aged 35-75 years) between January 1, 2014 and September 30, 2020. Patients were divided into three groups according to systolic BP (SBP) and diastolic BP (DBP), and the SUA levels in males and females were converted into three groups. Logistic regression was used to analyze the influence of sex and BP on the relationship between SUA levels and carotid plaque in patients with CHD. In the model of male BP subgroups, using the BP of group A (normal with SBP <120 mmHg and DBP <80 mmHg) as a reference, SUA levels were significantly correlated with the occurrence of carotid plaque under different BP states (P < .001). In contrast, in the model of female BP subgroups, most of these correlations were not statistically significant. Our study showed that SUA levels were significantly associated with carotid plaque occurrence in males with CHD, which remained significant across different BP states.

Risk factors for peripheral artery disease and diabetic peripheral neuropathy among patients with type 2 diabetes

AIMS

To investigate the prevalence of peripheral artery disease (PAD) and diabetic peripheral neuropathy (DPN) and the associated risk factors among Chinese patients with type 2 diabetes mellitus.

METHODS

A cross-sectional study was conducted using data between November 1, 2018, and December 31, 2022. PAD was defined as ABI ≤ 0.9. DPN diagnosis involved specialized physician assessments using questionnaires and vibration perception threshold tests. Logistic regression analysis was used to identify related factors. We also evaluated the association between the clustering of risk factors and disease incidence.

RESULTS

The study population comprised 13,315 patients (mean age: 63.3 years). 4.9 % of the patients had PAD and 43.9 % had DPN. Multivariate regression analysis revealed advanced age, smoking, hypertension, coronary heart disease, dyslipidemia, elevated HbA1c, and uric acid levels as independent risk factors for PAD. For DPN, independent risk factors included advanced age, female gender, hypertension, coronary heart disease, elevated total cholesterol, triglycerides, lipoprotein(a), fasting plasma glucose, HbA1c, alkaline phosphatase, cystatin C, albumin-to-creatinine ratio, and elevated homocysteine levels, whereas apolipoprotein A was a protective factor. The clustering of risk factors was prevalent and associated with higher disease risk.

CONCLUSIONS

Our study contributed to identifying high-risk individuals and improving lower limb health among diabetic individuals.

Exploring the Multifaceted Nexus of Uric Acid and Health: A Review of Recent Studies on Diverse Diseases

The prevalence of patients with hyperuricemia or gout is increasing worldwide. Hyperuricemia and gout are primarily attributed to genetic factors, along with lifestyle factors like consuming a purine-rich diet, alcohol and/or fructose intake, and physical activity. While numerous studies have reported various comorbidities linked to hyperuricemia or gout, the range of these associations is extensive. This review article focuses on the relationship between uric acid and thirteen specific domains: transporters, genetic factors, diet, lifestyle, gout, diabetes mellitus, metabolic syndrome, atherosclerosis, hypertension, kidney diseases, cardiovascular diseases, neurological diseases, and malignancies. The present article provides a comprehensive review of recent developments in these areas, compiled by experts from the Young Committee of the Japanese Society of Gout and Uric and Nucleic Acids. The consolidated summary serves to enhance the global comprehension of uric acid-related matters.

New Dawn for Atherosclerosis: Vascular Endothelial Cell Senescence and Death

Endothelial cells (ECs) form the inner linings of blood vessels, and are directly exposed to endogenous hazard signals and metabolites in the circulatory system. The senescence and death of ECs are not only adverse outcomes, but also causal contributors to endothelial dysfunction, an early risk marker of atherosclerosis. The pathophysiological process of EC senescence involves both structural and functional changes and has been linked to various factors, including oxidative stress, dysregulated cell cycle, hyperuricemia, vascular inflammation, and aberrant metabolite sensing and signaling. Multiple forms of EC death have been documented in atherosclerosis, including autophagic cell death, apoptosis, pyroptosis, NETosis, necroptosis, and ferroptosis. Despite this, the molecular mechanisms underlying EC senescence or death in atherogenesis are not fully understood. To provide a comprehensive update on the subject, this review examines the historic and latest findings on the molecular mechanisms and functional alterations associated with EC senescence and death in different stages of atherosclerosis.

Role of Uric Acid in Vascular Remodeling: Cytoskeleton Changes and Migration in VSMCs

The mechanisms by which hyperuricemia induces vascular dysfunction and contributes to cardiovascular disease are still debated. Phenotypic transition is a property of vascular smooth muscle cells (VSMCs) involved in organ damage. The aim of this study was to investigate the effects of uric acid (UA) on changes in the VSMC cytoskeleton, cell migration and the signals involved in these processes. MOVAS, a mouse VSMC line, was incubated with 6, 9 and 12 mg/dL of UA, angiotensin receptor blockers (ARBs), proteasome and MEK-inhibitors. Migration property was assessed in a micro-chemotaxis chamber and by phalloidin staining. Changes in cytoskeleton proteins (Smoothelin B (SMTB), alpha-Smooth Muscle Actin (αSMA), Smooth Muscle 22 Alpha (SM22α)), Atrogin-1 and MAPK activation were determined by Western blot, immunostaining and quantitative reverse transcription PCR. UA exposition modified SMT, αSMA and SM22α levels (p < 0.05) and significantly upregulated Atrogin-1 and MAPK activation. UA-treated VSMCs showed an increased migratory rate as compared to control cells (p < 0.001) and a re-arrangement of F-actin. Probenecid, proteasome inhibition and ARBs prevented the development of dysfunctional VSMC. This study shows, for the first time, that UA-induced cytoskeleton changes determine an increase in VSMC migratory rate, suggesting UA as a key player in vascular remodeling.

Uric acid and arterial stiffness in children and adolescents: Role of insulin resistance and blood pressure

Several studies describe the association between serum uric acid (SUA) and arterial stiffness in adults. Uric acid contributes through several mechanisms to the increase in blood pressure (BP) and adversely affects the insulin signaling pathway. Moreover, SUA predict the development of hypertension and insulin resistance up to type 2 diabetes. Early arterial stiffening, estimated by carotid-femoral pulse wave velocity (PWV), may already be present in pediatric age. Aim of our study was to investigate the relationship between SUA and PWV in a pediatric population and its interaction with insulin resistance and BP. In 322 children and adolescents (56.2% male, mean age 11.3 [SD 2.8] years), we measured weight, height, waist circumference, BP and PWV. We also assayed SUA and estimated glomerular filtration rate (eGFR) and calculated HOMA-index as a marker of insulin resistance. Simple and multiple regression analyses were performed to assess variables associated with PWV. Mediation models were applied to identify the direct and indirect effects of individual variables on PWV. On univariate analysis, age (p < 0.001), waist circumference-to-height ratio (p = 0.036), systolic and diastolic BP (SBP and DBP) z-score (p < 0.001), heart rate (p = 0.028), SUA (p = 0.002), HOMA-index (p < 0.001), and eGFR (p = 0.014) were significantly associated with PWV. The multiple regression model showed that only age (p = 0.028), SBP z-score (p = 0.006), and heart rate (p = 0.001) were significantly associated with PWV. The results were superimposable when the DBP z-score replaced the SBP z-score in the model. Mediation models showed that the effect of eGFR on PWV was fully mediated by SUA (p = 0.015) and that the effect of SUA on PWV was totally mediated by HOMA-index (p < 0.001). Both SUA (p < 0.01) and HOMA-index (p < 0.01) had a significant association with higher SBP (DBP) z-scores. The double mediation model including both BP and HOMA-index showed that the SUA effect on PWV was totally mediated by both variables (p = 0.005, for HOMA-index, p = 0.004, for SBP z-score and p = 0.007, for combined effect). The results were superimposable when the DBP z-score replaced the SBP z-score in the model. In conclusion, insulin resistance and BP are both important mediators of the association between SUA and vascular stiffness in pediatric age.

Association between serum uric acid and arterial stiffness in a large-aged 40-70 years old population

Arterial stiffness (AS), measured by arterial stiffness index (ASI), is a determinant in cardiovascular (CV) diseases. A high serum uric acid (SUA) level is a known risk factor for CV disease. The authors investigated the relationship between SUA and ASI in the middle-age UK Biobank population study. AS was defined as ASI > 10 m/s. A cross-sectional study was conducted from 126 663 participants. Participants were divided into four quartiles according to SUA levels and sex. Sex multivariate analyses were performed with adjustment for confounding factors. The average ASI for overall participants was 9.3 m/s (SD: 2.9); 9.9 m/s (SD: 2.8) for men and 8.7 m/s (SD: 2.9) for women (P < .001). Men presented higher SUA rate (351.3 mmol/L (SD:67.9)) than women (270.7 mmol/L (SD:64.4)), P < .001. In men multivariate analysis, SUA remained a determinant of AS, with an increase in the strength of the association between the quartiles, Q4 versus Q1, OR = 1.10 [1.05-1.16], P < .001, Q3 versus Q1, OR = 1.09 [1.04-1.14], P < .001 but not between Q2 and Q1 (P = .136). In women, SUA remained significant for AS, with an increase in the strength of the association between the quartiles, Q4 versus Q1, OR = 1.22 [1.15-1.30], P < .001, Q3 versus Q1, OR = 1.13 [1.07-1.19], P < .001 and no difference between Q2 and Q1 (P = .101). When applying continuous SUA values in the multivariate analysis, SUA remained significant (P < .001), with a Youden index value for men = 338.3 mmol/L and for women = 267.3 mmol/L. High SUA levels were associated with AS, suggesting that SUA could be used as a predictor of atherosclerosis.

Metabolomics of Arterial Stiffness

Arterial stiffness (AS) is one of the earliest detectable signs of structural and functional alterations of the vessel wall and an independent predictor of cardiovascular events and death. The emerging field of metabolomics can be utilized to detect a wide spectrum of intermediates and products of metabolism in body fluids that can be involved in the pathogenesis of AS. Research over the past decade has reinforced this idea by linking AS to circulating acylcarnitines, glycerophospholipids, sphingolipids, and amino acids, among other metabolite species. Some of these metabolites influence AS through traditional cardiovascular risk factors (e.g., high blood pressure, high blood cholesterol, diabetes, smoking), while others seem to act independently through both known and unknown pathophysiological mechanisms. We propose the term 'arteriometabolomics' to indicate the research that applies metabolomics methods to study AS. The 'arteriometabolomics' approach has the potential to allow more personalized cardiovascular risk stratification, disease monitoring, and treatment selection. One of its major goals is to uncover the causal metabolic pathways of AS. Such pathways could represent valuable treatment targets in vascular ageing.

The Role of Urate in Cardiovascular Risk in Adolescents and Young Adults With Hypertension, Assessed by Pulse Wave Velocity

Background

Urate is increasingly recognized as a cardiovascular risk factor. It has been associated with hypertension, metabolic syndrome, obesity, chronic kidney disease and diabetes. Its prognostic role is less clear. The aim of our study was to evaluate the association between serum urate and pulse wave velocity, a measure of arterial stiffness in hypertensive adolescents and young adults.

Methods

269 adolescents and young adults with hypertension were included in the study. From all, anthropometric, blood pressure, pulse wave velocity and serum urate measurements were made. Variables were compared between sex, participants with or without obesity and with or without elevated urate.

Results

In multiple regression analysis for urate as dependent variable gender and diastolic pressure were found to be statistically significant. The difference between urate levels were found between boys and girls (p < 0.001), obese and non-obese (p < 0.001); however, pulse wave velocity did not differ between hyper- and eu-uricemic group (p = 0.162).

Conclusion

Associations between urate, gender, diastolic blood pressure and obesity were confirmed, however, no significant associations between pulse wave velocity and urate were detected.

Increased Impact of Serum Uric Acid on Arterial Stiffness and Atherosclerosis in Females

AIMS

Serum uric acid increases with metabolic disorders; however, whether the effects of uric acid on atherosclerosis are different in females and males has not been sufficiently evaluated. Therefore, this study compared the impact of uric acid on arterial stiffness and atherosclerosis between females and males.

METHODS

We enrolled 10196 untreated middle-aged subjects (46±8 years, 3021 females and 7175 males) who underwent periodic health check-ups. Serum uric acid levels were measured and arterial stiffness and atherosclerosis were assessed by the cardio-ankle vascular index (CAVI), carotid intima-media thickness (IMT), and plaque, using ultrasound imaging.

RESULTS

Females with increased arterial stiffness (CAVI ≥ 8.0) or carotid plaques had higher uric acid than those without (P＜0.0001), but males did not. In multivariable regression analyses including overall participants, uric acid was significantly associated with the CAVI, where sex interacted with uric acid. In sex-specific analyses, uric acid was significantly associated with the CAVI, but not with carotid IMT, in both sexes. However, logistic regression analyses revealed that serum uric acid was independently associated with the presence of carotid plaques in females. The exclusion of subjects with abdominal obesity or metabolic syndrome from the analysis did not alter the results in females.

CONCLUSIONS

Serum uric acid was significantly associated with the CAVI in both sexes, but the interaction of sex was confirmed and associated with a carotid plaque only in females. These findings support the increased impact of serum uric acid on arterial stiffness and atherosclerosis in females.

Serum Uric Acid and Kidney Disease Measures Independently Predict Cardiovascular and Total Mortality: The Uric Acid Right for Heart Health (URRAH) Project

Background: Serum uric acid predicts the onset and progression of kidney disease, and the occurrence of cardiovascular and all-cause mortality. Nevertheless, it is unclear which is the appropriate definition of hyperuricemia in presence of chronic kidney disease (CKD). Our goal was to study the independent impact of uric acid and CKD on mortality. Methods: We retrospectively investigated 21,963 patients from the URRAH study database. Hyperuricemia was defined on the basis of outcome specific cut-offs separately identified by ROC curves according to eGFR strata. The primary endpoints were cardiovascular and all-cause mortality. Results: After a mean follow-up of 9.8 year, there were 1,582 (7.20%) cardiovascular events and 3,130 (14.25%) deaths for all causes. The incidence of cardiovascular and all-cause mortality increased in parallel with reduction of eGFR strata and with progressively higher uric acid quartiles. During 215,618 person-years of follow-up, the incidence rate for cardiovascular mortality, stratified based on eGFR (>90, between 60 and 90 and <60 ml/min) was significantly higher in patients with hyperuricemia and albuminuria (3.8, 22.1 and 19.1, respectively) as compared to those with only one risk factor or none (0.4, 2.8 and 3.1, respectively). Serum uric acid and eGFR significantly interact in determining cardiovascular and all-cause mortality. For each SUA increase of 1 mg/dl the risk for mortality increased by 10% even after adjustment for potential confounding factors included eGFR and the presence of albuminuria. Conclusions: hyperuricemia is a risk factor for cardiovascular and all-cause mortality additively to eGFR strata and albuminuria, in patients at cardiovascular risk.

Metabolic syndrome and its components predict the development of arterial stiffening in a sample of adult men

BACKGROUND AND OBJECTIVE

Metabolic syndrome (MS) and its components are associated with greater cardiovascular risk. A number of studies found a positive association between MS and vascular damage, but few observational studies evaluated the predictive role of MS on arterial stiffening (AS). Therefore, the aim of this study was to estimate the ability of MS and its components to predict the risk of AS in an 8-year follow-up of a sample of adult men (Olivetti Heart Study).

METHODS

The analysis included 778 men without AS (pulse pressure >60 mmHg) at baseline. A positive diagnosis of MS was made by recognized criteria, if at least three components were present.

RESULTS

At the end of the follow-up period, there was an incidence of 11% in AS. The percentage of participants that developed AS was greater in the MS group than those without MS, also after adjustment for main confounders (odds ratio: 2.5, 95% confidence interval: 1.3-4.9). The risk of AS also increased with increase in the numbers of MS elements (p for trend <.01). In addition, the analysis of the predictive role of the single MS component showed that high blood pressure (HBP) was the strongest predictor.

CONCLUSIONS

The results of this prospective study indicate a predictive role of MS on AS, independently of main confounders. In addition, HBP seems the strongest predictor of AS among MS components.

Impact of Serum Uric Acid Concentration on the Risk of Cardiovascular Disease: A Cohort Study Conducted in Northern China

BACKGROUND

The results of previous studies of the relationship between serum uric acid (SUA) and the risk of cardiovascular disease (CVD) have been inconsistent due to confounding factors caused by other known cardiovascular risk factors.

OBJECTIVES

This study aimed to evaluate the relationship between SUA and incident CVD in middle-aged and elderly Chinese people, who were stratified according to body mass index (BMI).

METHODS

This study recruited 5,721 participants of 40-75 years of age, who were free of CVD at baseline and who underwent follow-up from 2008 to 2017. Participants were categorized in SUA quintiles. Cox proportional hazard and Kaplan-Meier survival analysis were used to compare CVD incidence among the SUA groups. The correlations between SUA and CVD incidence in groups with differing BMI and waist circumference (WC) were also analyzed. A P value <0.05 was considered statistically significant.

RESULTS

During a mean follow-up period of 7.6 years, CVD incidence increased with SUA (log-rank test p<0. 001). Compared with the first quintile, the adjusted hazard ratios (95% confidence interval (CI)) for the development of CVD were 1.08 (0.78-1.65), 1.17 (0.88-1.77), 1.47 (1.12-2.21), and 1.68 (1.28-2.44) for the second to fifth quintiles, respectively. This relationship was clearer in participants with normal BMI and WC. The adjusted hazard ratio for each 100 μmol/L increase in SUA was 1.13 (95% CI: 1.02-1.39) for CVD events.

CONCLUSIONS

High SUA is an independent risk factor for CVD in middle-aged and elderly northern Chinese people. This effect is maintained even after stratification according to measures of leanness/obesity.

Plasma uric acid is related to large arterial stiffness but not to other hemodynamic variables: a study in 606 normotensive and never-medicated hypertensive subjects

Background

Elevated level of plasma uric acid (PUA) has been associated with cardiovascular disease, but whether uric acid is an independent risk factor or merely a marker remains controversial.

Methods

We investigated in a cross-sectional setting the association of PUA with hemodynamics in 606 normotensive and never-medicated hypertensive subjects (295 men, 311 women, age range 19–73 years) without cardiovascular disease or gout. In all except 15 individuals, PUA was within the normal range. Supine hemodynamics were recorded using whole-body impedance cardiography and radial tonometric pulse wave analysis.

Results

The mean concentrations of PUA in age, sex and body mass index adjusted quartiles were 234, 278, 314, and 373 µmol/l, respectively. The highest PUA quartile presented with higher aortic to popliteal pulse wave velocity (PWV) than the lowest quartile (8.7 vs. 8.2 m/s, p = 0.026) in analyses additionally adjusted for plasma concentrations of C-reactive protein, low density lipoprotein cholesterol, triglycerides, and mean aortic blood pressure. No differences in radial and aortic blood pressure, wave reflections, heart rate, cardiac output, and systemic vascular resistance were observed between the quartiles. In linear regression analysis, PUA was an independent explanatory factor for PWV (β = 0.168, p < 0.001, R² of the model 0.591), but not for systolic or diastolic blood pressure. When the regression analysis was performed separately for men and women, PUA was an independent predictor of PWV in both sexes.

Conclusions

PUA concentration was independently and directly associated with large arterial stiffness in individuals without cardiovascular disease and PUA levels predominantly within the normal range. Trial registration ClinicalTrials.gov NCT01742702.

Sex-Specific Association of Uric Acid and Kidney Function Decline in Taiwan

An elevated serum urate concentration is associated with kidney damage. Men’s uric acid levels are usually higher than women’s. However, postmenopausal women have a higher risk of gout than men, and comorbidities are also higher than in men. This study examined the sex differences in the relationship between hyperuricemia and renal progression in early chronic kidney disease (CKD) and non-CKD, and further examined the incidence of CKD in non-CKD populations among patients over 50 years of age. We analyzed 1856 women and 1852 men participating in the epidemiology and risk factors surveillance of the CKD database. Women showed a significantly higher risk of renal progression and CKD than men within the hyperuricemia group. After adjusting covariates, women, but not men resulted in an hazard ratio (HR) for developing renal progression (HR = 1.12; 95% CI 1.01–1.24 in women and HR = 1.03; 95% CI 0.93–1.13 in men) and CKD (HR = 1.11; 95% CI 1.01–1.22 in women and HR = 0.95; 95% CI 0.85–1.05 in men) for each 1 mg/dL increase in serum urate levels. The association between serum urate levels and renal progression was stronger in women. Given the prevalence and impact of kidney disease, factors that impede optimal renal function management in women and men must be identified to provide tailored treatment recommendations.

Uric Acid Is Not Associated With Blood Pressure Phenotypes and Target Organ Damage According to Blood Pressure Phenotypes

BACKGROUND

Hypertensive patients with increased serum uric acid (SUA) are at increased cardiovascular (CV) risks. Both the European and American hypertension guidelines endorse the utilization of 24 h-ambulatory blood pressure monitoring (24 h-ABPM) for hypertensive patients with increased CV risk. While there is difference in identifying uric acid as a CV risk factor between the European and American guidelines. Therefore, it is unknown whether 24 h-ABPM should be used routinely in hypertensive patients with increased SUA.

METHODS

To address this knowledge gap, we investigated (i) the correlation between SUA and 24 h-ABP; (ii) the association between SUA and blood pressure (BP) phenotypes (controlled hypertension [CH], white-coat uncontrolled hypertension [WCUH], masked uncontrolled hypertension [MUCH], and sustained uncontrolled hypertension [SUCH]); (iii) the association between SUA and target organ damage (TOD: microalbuminuria, left ventricular hypertrophy [LVH], and arterial stiffness) according to BP phenotypes.

RESULTS

In 1,336 treated hypertensive patients (mean age 61.2 and female 55.4%), we found (i) there was no correlation between SUA and 24 h, daytime, and nighttime systolic blood pressure/diastolic blood pressure, respectively; (ii) in reference to CH, SUA increase was not associated WCUH (odds ratio [OR] 0.968, P = 0.609), MUCH (OR 1.026, P = 0.545), and SUCH (OR 1.003, P = 0.943); (iii) the overall prevalence of microalbuminuria, LVH, and arterial stiffness was 2.3%, 16.7%, and 23.2%, respectively. After adjustment for covariates, including age, sex, smoking, body mass index, diabetes mellitus, and estimated glomerular filtration rate, there was no association between SUA and TOD in all BP phenotypes.

CONCLUSIONS

These preliminary findings did not support routine use of 24 h-ABPM in treated hypertensive patients with increased SUA.

Increased serum uric acid levels are associated to renal arteriolopathy and predict poor outcome in IgA nephropathy

BACKGROUND AND AIMS

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a leading cause of end stage renal disease (ESRD). In addition to classical progression factors, other atherosclerosis-related factors, including hyperuricemia (HU), have been associated to the renal progression of IgAN. Increased serum uric acid (SUA) levels are well known to be concomitant of cardiovascular and kidney diseases, and have been proposed to be implicated in the development of arteriolar damage (AD). The aim of the present study was to explore the correlation between SUA levels, renal damage and its implication for outcome in IgAN patients.

METHODS AND RESULTS

Clinical, laboratory and histologic data of 145 patients with biopsy proven IgAN were collected and retrospectively analyzed to determine the correlation between SUA levels, renal damage and the primary outcome (death or ESRD). Biopsy-proven AD was defined by the presence of arteriolar hyalinosis and/or intimal thickening. HU, defined as the highest SUA gender-specific tertile, was >7.7 mg/dl for males and >6.2 mg/dl for females. The prevalence of AD increased with the increase in the SUA level tertiles (p = 0.02). At logistic regression analysis SUA was independently related to the presence of AD (OR 1.75 [95%CI 1.10-2.93], p = 0.03). HU and AD had a synergic impact on progression of IgAN. Patients having both AD and HU, showed a reduced survival free from the primary outcome as compared to those having only one risk factor or neither (p = 0.01).

CONCLUSIONS

SUA levels are independently associated with AD and poor prognosis in patients with IgAN.

Circulating angiopoietin-like protein 2 levels and arterial stiffness in patients receiving maintenance hemodialysis: A cross-sectional study

BACKGROUND AND AIMS

Chronic low-grade inflammation is receiving much attention as a critical pathology that induces various aging phenotypes, a concept known as "inflammaging". Uremic patients undergoing hemodialysis therapy show vascular aging phenotypes characterized by greater arterial stiffness and calcification compared to healthy controls of the same generation. In the current study, we investigated whether levels of inflammaging markers in the circulation were associated with vascular aging phenotypes in hemodialysis patients, as estimated by the cardio-ankle vascular index (CAVI).

METHODS

We conducted a multicenter cross-sectional study of 412 patients receiving hemodialysis and evaluated the relationship between circulating hs-CRP or ANGPTL2 levels, as markers of inflammaging, and CAVI.

RESULTS

Of 412 patients, 376 were analyzed statistically. While circulating hs-CRP levels had no significant association with CAVI, generalized linear models revealed that high circulating ANGPTL2 levels were significantly associated with increasing CAVI after adjustment for classical metabolic factors and hemodialysis-related parameters [β 0.63 (95%CI 0.07-1.18)]. Exploratory analysis revealed that high circulating ANGPTL2 levels were also strongly associated with increased CAVI, particularly in patients with conditions of increased vascular mechanical stress, such elevated blood pressure [β 1.00 (95%CI 0.23-1.76)], elevated pulse pressure [β 0.75 (95%CI 0.52-0.98)], or excess body fluid [β 1.25 (95%CI 0.65-1.84)].

CONCLUSIONS

We conclude that circulating levels of ANGPTL2 rather than hs-CRP are positively associated with CAVI in the uremic population and that ANGPTL2 could be a unique marker of progression of vascular aging in patients receiving hemodialysis.

Arterial Stiffness Preceding Diabetes: A Longitudinal Study

RATIONALE

Previous studies on the relationship between diabetes and arterial stiffness were mostly cross-sectional. A few longitudinal studies focused on one single direction. Whether the association between arterial stiffness and diabetes is bidirectional remains unclear to date.

OBJECTIVE

To explore the temporal relationship between arterial stiffness and fasting blood glucose (FBG) status.

METHODS AND RESULTS

Included were 14 159 participants of the Kailuan study with assessment of brachial-ankle pulse wave velocity (baPWV) from 2010 to 2015, and free of diabetes, cardiovascular and cerebrovascular diseases, and chronic kidney disease at baseline. FBG and baPWV were repeatedly measured at baseline and follow-ups. Cox proportional hazard regression model was used to estimate hazard ratios and 95% confidence intervals (CIs) of incident diabetes across baseline baPWV groups: <1400 cm/s (ref), 1400≤ baPWV <1800 cm/s, and ≥1800 cm/s. Path analysis was used to analyze the possible temporal causal relationship between baPWV and FBG, among 8956 participants with repeated assessment of baPWV and FBG twice in 2010 to 2017. The mean baseline age of the observed population was 48.3±12.0 years. During mean 3.72 years of follow-up, 979 incident diabetes cases were identified. After adjusting for potential confounders, the hazard ratio (95% CI) for risk of diabetes was 1.59 (1.34-1.88) for the borderline arterial stiffness group and 2.11 (1.71-2.61) for the elevated arterial stiffness group, compared with the normal ideal arterial stiffness group. In the path analysis, baseline baPWV was associated with follow-up FBG (the standard regression coefficient was 0.09 [95% CI, 0.05-0.10]). In contrast, the standard regression coefficient of baseline FBG for follow-up baPWV (β=0.00 [95% CI, -0.02 to 0.02]) was not significant.

CONCLUSIONS

Arterial stiffness, as measured by baPWV, was associated with risk of developing diabetes. Arterial stiffness appeared to precede the increase in FBG.

Uric Acid and Vascular Damage in Essential Hypertension: Role of Insulin Resistance

Increased levels of uric acid (UA) have been shown to be correlated with many clinical conditions. Uric acid may adversely affect the insulin signalling pathway inducing insulin resistance (IR). Several studies report the association between arterial stiffness (AS), an early indicator of atherosclerosis, and UA. The purpose of the present study was to evaluate the association between UA and AS, considering the potential role of IR. We enrolled 1114 newly diagnosed, never-treated hypertensive patients. Insulin resistance was assessed by the homeostatic model assessment (HOMA) index. Arterial stiffness was evaluated as the measurement of the carotid–femoral pulse wave velocity (PWV). The study cohort was divided into subgroups, according to increasing tertiles of UA. The mean values of UA were 5.2 ± 1.6 mg/dL in the overall population. Pulse wave velocity was linearly correlated with UA (p < 0.0001), HOMA (p < 0.0001), high sensitivity C-reactive protein (p < 0.0001), systolic blood pressure (p < 0.0001) and LDL cholesterol (p = 0.005). Uric acid was the strongest predictor of PWV and was associated with the highest risk for increased AS. The interaction analysis showed that the joint effect of increased UA and HOMA was significantly higher than that expected in the absence of interaction under the additive model, indicating that the two biomarkers synergically interacted for promoting vascular damage. Our data showed that UA interacted with IR to increase AS in a large cohort of newly diagnosed, never-treated hypertensive patients.

Higher baseline uric acid concentration is associated with non-attainment of optimal blood pressure

A significant relationship exists between elevated uric acid concentration and both prevalent and incident hypertension; however, data regarding the influence of higher uric acid concentration at baseline on blood pressure control by antihypertensive drugs is scarce. Thus, a prospective cohort study was performed. The study outcome was the non-attainment of optimal blood pressure (NOBP). NOBP level was defined according to the Japanese hypertension guideline. This study enrolled a Japanese community-based cohort (N = 8,664; age 65.5 ± 6.4 years; women, 55.0%) who were not using antihypertensive drugs on the first visit for a health check-up program but started using antihypertensive drug(s) on the next-year visit. The participants were classified into quartiles based basic uric acid concentration. Odds ratios (ORs) were calculated for NOBP as the primary outcome measure. Multivariable logistic analysis showed that quartile 4 was significantly associated with NOBP when quartile 1 was set as the reference (OR (95% confidence interval), 1.36 (1.16-1.59), p<0.01), adjusted for potential confounders, such as age, sex, body mass index, presence of diabetes/dyslipidemia/chronic kidney disease (CKD), history of cardiovascular disease, daily drinking, and current smoking. In the subgroup analysis of female participants and participants with diabetes and CKD, a significant association was observed between +1 mg/dL of uric acid and NOBP. Higher uric acid concentration at baseline was significantly associated with NOBP on the first use of antihypertensive drug(s).

High serum uric acid is associated with increased arterial stiffness in hypertension

Serum uric acid level has been found to be associated with cerebrovascular diseases. However, whether serum uric acid level is a risk factor for arterial stiffness in the hypertension population is unclear. This study was designed to determine the relationship between serum uric acid level and arterial stiffness in the hypertension population. A total of 10450 participants were evaluated for the risk of arterial stiffness. Brachial-ankle pulse wave velocity (baPWV) was assessed, and high baPWV was determined as the highest quartile of baPWV values in a sex-specific manner. We evaluated the association between serum uric acid level and baPWV through multivariate-adjusted linear and logistic regression analyses. There was a significant difference on high baPWV between patients with quartiles of serum uric acid level in females and males (p<0.01), respectively. The odds ratios (95% CI) of the highest baPWV quartile across the sex-specific serum uric acid level were 1.0, 1.71 (1.35, 2.17), 1.75 (1.38, 2.23), and 1.95 (1.51, 2.51) in female, and 1.0, 1.33 (1.09, 1.64), 1.36 (1.11, 1.67), and 1.67 (1.36, 2.04) in male after adjusting for potential confounders. In conclusion, serum uric acid level could be considered as an important risk factor for arterial stiffness in Chinese hypertension population.

Gender-Specific Association between Serum Uric Acid and Incident Fundus Arteriosclerosis in Chinese Population: A Retrospective Cross-Sectional Study

Elevated levels of serum uric acid (SUA) were considered to be risk factors for cardiovascular disease, it has been found to be associated with increased arteriosclerosis. The aim of this study was to explore the gender specific relationship between SUA and fundus arteriosclerosis in a healthy population. In a retrospective cross-sectional study, 23474 individuals without diabetes and hypertension were included in the present study. SUA levels were cut to four groups as Q1 to Q4, according to the quartiles. The odds ratio and 95% confidence interval of different SUA levels were estimated by a binomial logistic regression model. A restrictive cubic spline method was used to estimate the dose-response relationship between SUA and fundus arteriosclerosis. Subgroup analysis was performed to find the gender-specific association between SUA and incident fundus arteriosclerosis. In males, after adjusting for confounding factors, the highest SUA level was significantly associated with the risk of incident fundus arteriosclerosis. The OR with 95%CI for Q4 was 1.44(1.18, 1.76), Q1 as a reference. Specially, for females, SUA level was not associated with the incidence of fundus arteriosclerosis. In conclusion, elevated levels of SUA were associated with the incidence of fundus arteriosclerosis in males, but not in females.

The relationship between elevated serum uric acid and arterial stiffness in a healthy population

OBJECTIVE

This study aims to investigate the relationship between serum uric acid and arterial stiffness in a healthy population.

METHODS

Among the 979 participants, baPWV was non-invasively measured, the circulating levels of uric acid were tested, and the uric acid polymorphisms (rs2231142 and rs11722228) were genotyped. Then, the Mendelian randomization method was employed to test the relationship between serum uric acid and arterial stiffness in a healthy population.

RESULTS

After adjusting for age, gender, antihypertensive medication, body mass index, waist-to-hip ratio, urea nitrogen, creatinine and diabetic mellitus, there was a significant allelic difference in uric acid levels for each genotype (P < 0.0001 for rs2231142; P = 0.007 for rs11722228). However, there were no differences on the potential confounders between the genotypes of rs2231142 and rs11722228 (P > 0.05). The baPWV was significantly associated with circulating levels of uric acid after adjusting for cardiovascular risk factors and other potential confounders (P = 0.002). However, neither the single polymorphism, nor the accumulation of culprit alleles was associated with baPWV (P = 0.92 for rs2231142; P = 0.60 for rs11722228; P for trend = 0.77 for the combined analysis of culprit alleles).

CONCLUSION

These results do not support the causal role of circulating levels of uric acid in the development of arterial stiffness.

Hyperuricemia and Risk of Cardiovascular Outcomes: The Experience of the URRAH (Uric Acid Right for Heart Health) Project

The latest European Guidelines of Arterial Hypertension have officially introduced uric acid evaluation among the cardiovascular risk factors that should be evaluated in order to stratify patient's risk. In fact, it has been extensively evaluated and demonstrated to be an independent predictor not only of all-cause and cardiovascular mortality, but also of myocardial infraction, stroke and heart failure. Despite the large number of studies on this topic, an important open question that still need to be answered is the identification of a cardiovascular uric acid cut-off value. The actual hyperuricemia cut-off (> 6 mg/dL in women and 7 mg/dL in men) is principally based on the saturation point of uric acid but previous evidence suggests that the negative impact of cardiovascular system could occur also at lower levels. In this context, the Working Group on uric acid and CV risk of the Italian Society of Hypertension has designed the Uric acid Right for heArt Health project. The primary objective of this project is to define the level of uricemia above which the independent risk of CV disease may increase in a significantly manner. In this review we will summarize the first results obtained and describe the further planned analysis.

Association between uric acid and pulse wave velocity in hypertensive patients and in the general population: a systematic review and meta-analysis

Purpose: The association between serum uric acid (SUA) and pulse wave velocity (PWV), has been extensively evaluated but with some discrepancies in results. A further limitation refers to the fact that only few data were analyzed taking into account the possible effects of gender. The purpose of this study was to estimate the association between SUA and arterial stiffness in general population and hypertensive patients, as a whole population and as divided by gender, by pooling results from existing studies.Materials and methods: Carotid-femoral and brachial-ankle PWV (cf- and ba-PWV) have been analyzed separately and subgroup analyses by gender are reported. Among 692 potentially relevant works, 24 articles were analyzed.Results: Seven studies referred to cf-PWV in the general population with an overall positive association at adjusted analysis for both males and females (beta regression coefficient (ß): 0.07; 95%CI: 0.03; 0.11 and ß: 0.06; 95%CI: 0.03; 0.09, respectively). Twelve studies referred to ba-PWV in the general population with the finding of a positive association at adjusted analysis for females (ß: 0.04; 95% confidence interval (CI): 0.01;0.07), but not for males (ß: 0.13; 95%CI: -0.09; 0.34). In hypertensive patients only four studies evaluated cf-PWV and one ba-PWV with only one study (with cf-PWV) finding positive association.Conclusion: The association between SUA and cf-PWV resulted significant in general population in both males and females while it was only significant for female regarding ba-PWV. Furthermore, the few available studies found no significant relationship between SUA and both cf- and ba-PWV in hypertensive subjects.

Uric Acid and Arterial Stiffness

Hyperuricemia is usually associated with hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Accumulating data from epidemiological studies indicate an association of increased uric acid (UA) with cardiovascular diseases. Possible pathogenic mechanisms include enhancement of oxidative stress and systemic inflammation caused by hyperuricemia. Arterial stiffness may be one of the possible pathways between hyperuricemia and cardiovascular disease, but a clear relationship between increased UA and vascular alterations has not been confirmed. The review summarizes the epidemiological studies investigating the relationship between UA and arterial stiffness and highlights the results of interventional studies evaluating arterial stiffness parameters in patients treated with UA-lowering drugs.

Relationship between carotid-femoral pulse wave velocity and uric acid in subjects with hypertension and hyperuricemia

Increasing of arterial stiffness is the pathophysiological characteristic of hypertension. Carotid-femoral pulse wave velocity (CF-PWV) is an index of arterial stiffness. Serum uric acid has been found to be involved the development of hypertension. We investigated the relationship between CF-PWV and serum uric acid in subjects with hypertension and hyperuricemia. 651 subjects (M/F 271/380) were divided into four groups, group 1: subjects without hypertension and hyperuricemia; group 2: hypertension subjects without hyperuricemia; group 3: hyperuricemia subjects without hypertension; group 4: subjects with hypertension and hyperuricemia. CF-PWV was measured by Complior apparatus. Results showed that levels of CF-PWV (10.75 ± 2.03 vs. 10.06 ± 1.98 m/s, p < 0.001) and serum uric acid (319.33 ± 80.12 vs. 298.78 ± 74.88 umol/L, p = 0.001) were significantly higher in hypertensive (groups 2 + 4) group than in normotensive (groups 1 + 3) group. CF-PWV was significantly higher in group 4 than group 1, group 2 and group 3 (ANOVA analysis: F = 13.348, p < 0.001; 11.78 ± 2.10 vs. 9.98 ± 1.98, 10.52 ± 1.93, 10.56 ± 1.99 m/s, all p < 0.05, respectively). There was positive correlation between CF-PWV and serum uric acid in entire study group (r = 0.187, p < 0.001), even after adjusting for gender, body mass index, systolic blood pressure (SBP) and diastolic blood pressure (r = 0.100, p = 0.015). Multiple linear regressions showed that SBP, age, benzbromarone, statin and serum uric acid were independent associating factors of CFPWV in all subjects (β = 0.310, p < 0.001; β = 0.330, p < 0.001; β = 0.172, p = 0.002; β = -0.143, p = 0.006; β = 0.126, p = 0.027; respectively). In conclusions, CF-PWV was significantly higher in hypertension subjects with hyperuricemia compared to hypertension without hyperuricemia subjects, and serum uric acid was an independent associating factor of CF-PWV.

Longitudinal association between serum uric acid levels and multiterritorial atherosclerosis

Multiterritorial atherosclerosis has dramatically increased annual risk of adverse cardiovascular events than atherosclerotic disease with single-artery affected. Serum uric acid (SUA) is an important predictor of stroke and atherosclerosis; however, which is supported by few direct evidence based on cohort studies. A prospective cohort study including 2644 North Chinese adults aged ≥40 years was performed in 2010-2012 to investigate the association between SUA and multiterritorial vascular stenosis. Hyperuricaemia was defined as SUA levels >6 and >7 mg/dL for males and females, respectively. All participants underwent twice transcranial Doppler (TCD) and bilateral carotid duplex ultrasound to evaluate intracranial artery stenosis (ICAS) and extracranial arterial stenosis (ECAS) and peripheral arterial disease (PAD) was determined by ankle-brachial index (ABI) on January 2010 and January 2012 based on regular health check-ups. The cumulative incidence of vascular stenosis was significantly higher in subjects with hyperuricaemia than in those without hyperuricaemia (54.1% vs. 34.7%, P < 0.001). The adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for new on-set vascular stenosis due to hyperuricaemia and a 1-mg/dL change in SUA level were 1.75 (1.32-2.31) and 1.29 (1.21-1.38), respectively. Furthermore, in the gender-stratified analysis, the association between SUA levels and ICAS was statistically significant in males (OR: 2.02; 95% CI: 1.18-3.46), but not females (OR: 0.85, 95% CI: 0.41-1.76, P for interaction: 0.026).

Pulse wave velocity progression over a medium-term follow-up in hypertensives: Focus on uric acid

The role of uric acid (UA) on the arterial stiffness progression has been evaluated only in three studies. Our aim was to evaluate its role as a possible determinant of the pulse wave velocity (PWV) progression over a 3.7 ± 0.5 years follow-up period in hypertensive patients. Specific sex analysis was done due to the well-known sex interaction with UA levels. We enrolled 422 consecutive hypertensive outpatients. At baseline anamnestic, blood pressure (BP) and laboratory data as well as PWV were assessed. PWV was performed again at follow-up examination. Hyperuricemia was defined as a UA > 6 mg/dL for women and > 7 mg/dL for men. Baseline age was 53.2 ± 13 years, 58% were males, systolic and diastolic BP (SBP/DBP) 141.7 ± 17.7/86.8 ± 10.8 mm Hg, UA 5.2 ± 1.4 mg/dL, and PWV 8.5 ± 1.9 m/s. At follow-up, despite better BP values (-8.5 ± 24.6 for SBP and -7.5 ± 15.4 for DBP), PWV increases to 9.1 ± 2.3 m/s (P < 0.001) with mean ΔPWV of+ 0.5 ± 2.2 m/s. A total of 61 patients were hyperuricemic (14.4%), and they present higher PWV baseline (9.0 ± 2.5 vs 8.5 ± 1.8 m/s, P = 0.03) without significant differences in ΔPWV. Hyperuricemic female (6.2%, 11 patients) presents higher baseline PWV without significant differences in ΔPWV. No differences were found in arterial stiffness in hyperuricemic males (20.4%, 50 patients). UA showed association with baseline and ΔPWV in the whole population but it loses statistical significance at the linear regression model. Same figures were also for sex analysis. Our findings provide evidence that baseline UA levels are not determinants of PWV progression over a median follow-up of 3.8 years' in hypertensive patients.

Peroxynitrite-Mediated SIRT (Sirtuin)-1 Inactivation Contributes to Nicotine-Induced Arterial Stiffness in Mice

Objective- Inhibition of SIRT (sirtuin)-1, a nicotinamide adenine dinucleotide-dependent protein deacetylase, is linked to cigarette smoking-induced arterial stiffness, but the underlying mechanisms remain largely unknown. The aim of the present study was to determine the effects and mechanisms of nicotine, a major component of cigarette smoke, on SIRT1 activity and arterial stiffness. Approach and Results- Arterial stiffness, peroxynitrite (ONOO^-) formation, SIRT1 expression and activity were monitored in mouse aortas of 8-week-old C57BL/6 mice (wild-type) or Sirt1-overexpressing ( Sirt1 ^Super) mice with or without nicotine for 4 weeks. In aortas of wild-type mice, nicotine reduced SIRT1 protein and activity by ≈50% without affecting its mRNA levels. In those from Sirt1 ^Super mice, nicotine also markedly reduced SIRT1 protein and activity to the levels that were comparable to those in wild-type mice. Nicotine infusion significantly induced collagen I, fibronectin, and arterial stiffness in wild-type but not Sirt1 ^Super mice. Nicotine increased the levels of iNOS (inducible nitric oxide synthase) and the co-staining of SIRT1 and 3-nitrotyrosine, a footprint of ONOO^- in aortas. Tempol, which ablated ONOO^- by scavenging superoxide anion, reduced the effects of nicotine on SIRT1 and collagen. Mutation of zinc-binding cysteine 395 or 398 in SIRT1 into serine (C395S) or (C398S) abolished SIRT1 activity. Furthermore, ONOO^- dose-dependently inhibited the enzyme and increased zinc release in recombinant SIRT1. Finally, we found SIRT1 inactivation by ONOO^- activated the YAP (Yes-associated protein) resulting in abnormal ECM (extracellular matrix) remodeling. Conclusions- Nicotine induces ONOO^-, which selectively inhibits SIRT1 resulting in a YAP-mediated ECM remodeling. Visual Overview- An online visual overview is available for this article.

Involvement of Arterial Stiffness and Inflammation in Hyperuricemia-Related Development of Hypertension

This study analyzed repeated measurement data to clarify the longitudinal associations between hyperuricemia and the risk factors for the development of hypertension (ie, increased arterial stiffness, renal dysfunction, and inflammation), and then examined whether these risk factors show longitudinal associations with the development of hypertension. In 3274 Japanese men without hypertension, the brachial-ankle pulse wave velocity, blood pressure, estimated glomerular filtration rate, and serum uric acid and CRP (C-reactive protein) levels were measured annually over an 8-year period. Of these, 474 subjects developed hypertension by the end of the study period. Mixed model linear regression analysis revealed a significant longitudinal association of hyperuricemia with increase of the brachial-ankle pulse wave velocity (estimate=5.50, P=0.04), decrease of the estimated glomerular filtration rate (estimate=-2.02, P<0.01), and elevation of the CRP (estimate=0.08×10^-1, P=0.02). Hyperuricemia at the study baseline was associated with a significant odds ratio for the development of hypertension by the end of the study period. After adjustments for covariates, the brachial-ankle pulse wave velocity (estimate=0.51×10^-2, P<0.01) and CRP (estimate=1.91, P=0.03), but not estimated glomerular filtration rate, were found to show independent longitudinal associations with the new onset of hypertension. In Japanese men without hypertension, hyperuricemia may have a longitudinal association with the development of hypertension, and increased arterials stiffness and inflammation may be involved in the risk of development of hypertension associated with hyperuricemia.

Association between post-transplant serum uric acid levels and kidney transplantation outcomes

Background

Serum uric acid (UA) level has been reported to be associated with chronic allograft nephropathy and graft failure in patients who undergo kidney transplantation (KT). However, the role of serum UA level in renal graft survival remains controversial.

Objective

This study aimed to investigate the effect of mean serum UA level during two different post-KT periods on long-term renal graft outcomes in a large population cohort in which living donor KT prevails.

Material and methods

A retrospective cohort study was performed using KT data prospectively collected at a single institution. Patients (n = 2,993) were divided into low-, normal-, and high-UA groups according to the mean serum UA level within the first year (1-YR) and 1–5 years (5-YR) after transplantation.

Results

In the 1-YR Cox proportional hazards analysis, the low- and high-UA groups had a significantly decreased and increased risk, respectively, for overall graft failure (OGF), death-censored graft failure (DCGF), and composite event (return to dialysis, retransplantation, death from graft dysfunction, and 40% decline in estimated glomerular filtration rate) compared with the normal-UA group. Similarly, in the 5-YR analysis, the low-UA group had a significantly reduced risk of DCGF compared with the normal-UA group, whereas the high-UA group had a significantly increased risk of all three graft outcomes. In a marginal structural model, hyperuricemia had a significant causal effect on worsening graft outcomes, with consideration of all confounding variables (OGF: hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.33–3.78; DCGF: HR 2.38, 95% CI 1.09–4.9; composite event: HR 3.05, 95% CI 1.64–5.49).

Conclusions

A low-to-normal serum UA level within the first year and 1–5 years after KT is an independent factor for better renal allograft outcomes in the long-term follow-up period rather than high serum UA level.

Serum Uric Acid Levels are Associated with Cardiometabolic Risk Factors in Healthy Young and Middle-Aged Adults

Background

Observational studies have highlighted an association between serum uric acid (SUA) levels and cardiovascular risk factors. Despite the growing body of evidences, several studies were conducted in older individuals or in carriers of diseases susceptible to affect SUA levels and cardiometabolic risk markers.

Objective

To evaluate the relationship of SUA with body adiposity, metabolic profile, oxidative stress, inflammatory biomarkers, blood pressure and endothelial function in healthy young and middle-aged adults.

Methods

149 Brazilian adults aged 20-55 years, both sexes, underwent evaluation of body adiposity, SUA, fasting glucose and insulin, lipid profile, malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), adiponectin, blood pressure and endothelial function. Endothelial function was assessed by the reactive hyperemia index (RHI) derived from peripheral arterial tonometry method. Participants were allocated in two groups according to SUA levels: control group (CG; n = 130; men ≤ 7 mg/dL, women ≤ 6 mg/dL) and hyperuricemia group (HG; n = 19; men > 7 mg/dL, women > 6 mg/dL). A P-value < 0.05 was considered statistically significant.

Results

After adjustment for confounders, participants in HG compared with those in CG displayed higher body mass index (BMI): 34.15(33.36-37.19) vs.31.80 (26.26-34.42) kg/m²,p = 0.008, higher MDA: 4.67(4.03-5.30) vs. 3.53(3.10-4.07) ng/mL, p < 0.0001 and lower RHI: 1.68 ± 0.30 vs. 2.05 ± 0.46, p = 0.03). In correlation analysis adjusted for confounders, SUA was positively associated (p < 0.05) with BMI, waist circumference, LDL-cholesterol, triglycerides and MDA, and negatively associated (p < 0.05) with HDL-cholesterol, adiponectin and RHI.

Conclusions

This study suggests that in healthy young and middle-aged adults higher SUA levels are associated with higher body adiposity, unfavorable lipid and inflammatory phenotype, higher oxidative stress and impaired endothelial function.

Gender difference in the relationship between uric acid and pulse pressure among Korean adults

Hyperuricemia is associated with cardiovascular disease, but the relationship between uric acid (UA) and pulse pressure (PP) is unclear. Therefore, the present study assesses the relationship between UA and PP among Korean adults. Data from 6,310 subjects (2,800 men and 3,510 women) in the seventh Korean National Health and Nutrition Examination Survey (2016) were analyzed. After adjusting for related variables, the odds ratios (ORs) of hyperuricemia (UA ≥ 7.0 mg/dL in men or ≥ 6.0 mg/dL in women) in the high PP group (PP > 65.0 mmHg) in overall populations (OR, 1.563; 95% confidence interval [CI], 1.144-2.136) and women (OR, 1.631; 95% CI, 1.046-2.544) were significantly higher than those in normal PP, but not in men (OR, 1.309; 95% CI, 0.840-2.040). In conclusion, uric acid was positively associated with pulse pressure in women, but not in men.

Endothelial cell senescence in aging-related vascular dysfunction

Increased cardiovascular disease in aging is partly a consequence of the vascular endothelial cell (EC) senescence and associated vascular dysfunction. In this contest, EC senescence is a pathophysiological process of structural and functional changes including dysregulation of vascular tone, increased endothelium permeability, arterial stiffness, impairment of angiogenesis and vascular repair, and a reduction of EC mitochondrial biogenesis. Dysregulation of cell cycle, oxidative stress, altered calcium signaling, hyperuricemia, and vascular inflammation have been implicated in the development and progression of EC senescence and vascular disease in aging. A number of abnormal molecular pathways are associated with these underlying pathophysiological changes including Sirtuin 1, Klotho, fibroblast growth factor 21, and activation of the renin angiotensin-aldosterone system. However, the molecular mechanisms of EC senescence and associated vascular impairment in aging are not completely understood. This review provides a contemporary update on molecular mechanisms, pathophysiological events, as well functional changes in EC senescence and age-associated cardiovascular disease. This article is part of a Special Issue entitled: Genetic and epigenetic regulation of aging and longevity edited by Jun Ren & Megan Yingmei Zhang.

Uric acid levels are associated with endothelial dysfunction and severity of coronary atherosclerosis during a first episode of acute coronary syndrome

The role of serum uric acid in coronary artery disease has been extensively investigated. It was suggested that serum uric acid level (SUA) is an independent predictor of endothelial dysfunction and related to coronary artery lesions. However, the relationship between SUA and severity of coronary atherosclerosis evaluated via endothelial dysfunction using peripheral arterial tone (PAT) and the reactive hyperhemia index (RHI) has not been investigated during a first episode of acute coronary syndrome (ACS). The aim of our study was to address this point. We prospectively enrolled 80 patients with a first episode of ACS in a single-center observational study. All patients underwent coronary angiography, evaluation of endothelial function via the RHI, and SUA measurement. The severity of the coronary artery lesion was assessed angiographically, and patients were classified in three groups based on the extent of disease and Gensini and SYNTAX scores. Endothelial function was considered abnormal if RHI < 1.67. We identified a linear correlation between SUA and RHI (R² = 0.66 P < 0.001). In multivariable analyses, SUA remained associated with RHI, even after adjustment for traditional cardiovascular risk factors and renal function. SUA was associated with severity of coronary artery disease. SUA is associated with severity of coronary atherosclerosis in patients with asymptomatic hyperuricemia. This inexpensive, readily measured biological parameter may be useful to monitor ACS patients.

Sex-Dependent Associations of Serum Uric Acid with Brain Function During Aging

Serum uric acid (SUA) is an abundant natural antioxidant capable of reducing cellular oxidation, a major cause of neurodegenerative disease. In line with this, SUA levels are lower in Alzheimer's disease; however, the association between SUA and cognition remains unclear. Results from studies examining the effects of SUA on cognition may be difficult to interpret in the context of normal versus pathological aging. This study examined sex-specific associations of baseline SUA with cognition during aging. Data from dementia-free participants initially aged 26-99 (N = 1,451) recruited for the Baltimore Longitudinal Study of Aging (BLSA), were used in the current analyses. SUA was assessed using blood samples collected during research visits. Cognition was measured using five composite scores (verbal memory, attention, executive function, language, and visuospatial ability). At the first study visit, compared with women, men were older, more likely to be White, had more years of education, higher baseline SUA levels, and higher cardiovascular risk scores. Higher baseline SUA was associated with attenuated declines in attention (β= 0.006; p = 0.03) and visuospatial abilities (β= 0.007; p = 0.01) in men. There was a trend to suggest higher baseline SUA in men was associated with attenuated declines in language, but this finding did not reach statistical significance (p = 0.09). There were no significant findings with SUA and cognition in women. In this sample of cognitively healthy, community-dwelling adults, we found that higher SUA levels at baseline were associated with attenuated declines in attention and visuospatial abilities in men. SUA was not associated with cognition or change in cognition over time in women.

Uric acid levels are associated with endothelial dysfunction and severity of coronary atherosclerosis during a first episode of acute coronary syndrome

The role of serum uric acid in coronary artery disease has been extensively investigated. It was suggested that serum uric acid level (SUA) is an independent predictor of endothelial dysfunction and related to coronary artery lesions. However, the relationship between SUA and severity of coronary atherosclerosis evaluated via endothelial dysfunction using peripheral arterial tone (PAT) and the reactive hyperhemia index (RHI) has not been investigated during a first episode of acute coronary syndrome (ACS). The aim of our study was to address this point. We prospectively enrolled 80 patients with a first episode of ACS in a single-center observational study. All patients underwent coronary angiography, evaluation of endothelial function via the RHI, and SUA measurement. The severity of the coronary artery lesion was assessed angiographically, and patients were classified in three groups based on the extent of disease and Gensini and SYNTAX scores. Endothelial function was considered abnormal if RHI < 1.67. We identified a linear correlation between SUA and RHI (R² = 0.66 P < 0.001). In multivariable analyses, SUA remained associated with RHI, even after adjustment for traditional cardiovascular risk factors and renal function. SUA was associated with severity of coronary artery disease. SUA is associated with severity of coronary atherosclerosis in patients with asymptomatic hyperuricemia. This inexpensive, readily measured biological parameter may be useful to monitor ACS patients.

Baicalein decreases uric acid and prevents hyperuricemic nephropathy in mice

Baicalein, a natural flavonoid, is structurally advantageous for binding to xanthine oxidoreductase. In our study, molecular docking analysis and Surface Plasmon Resonance revealed a direct interaction between baicalein and xanthine oxidoreductase. Moreover, 50 mg/kg/d baicalein treatment significantly suppressed the viability of xanthine oxidoreductase in hyperuricemia mouse model. The data showed that baicalein remarkably prevented renal dysfunction, ameliorated kidney fibrosis, alleviated epithelial-mesenchymal transition and oxidative stress in hyperuricemia mice. Thus, we concluded that baicalein executed a kidney-protection action in hyperuricemia and therefore may be used as a therapeutic alternative for hyperuricemic nephropathy.

Association between serum uric acid and cardiovascular risk in nonhypertensive and nondiabetic individuals: The Taiwan I-Lan Longitudinal Aging Study

Serum uric acid level is a risk factor for cardiovascular disease (CVD). However, whether it is an independent risk factor or not remains controversial. We analyzed the association between serum uric acid level and cardiovascular risk. In total, 973 nonhypertensive and nondiabetic participants in the I-Lan Longitudinal Aging Study were eligible for this study. Subjects were divided into tertiles according to uric acid levels. The 10-year cardiovascular risk was calculated using Framingham risk score (FRS). Study subjects in the highest tertile of serum uric acid level were older, more likely to be male, and had higher systolic blood pressure, body mass index, carotid artery intima–media thickness and serum triglyceride, high-sensitivity C-reactive protein, and low-density lipoprotein cholesterol levels and lower serum high-density lipoprotein cholesterol levels (all p < 0.05). Subjects in the highest tertile had significantly higher FRS (p < 0.001). After adjusting for other risk factors, serum uric acid level remained associated significantly with the FRS (p < 0.05). In binary logistic regression analysis, the serum uric acid level was an independent predictive factor for high (≥20%) FRS (odds ratio 1.33, 95% confidence interval 1.10–1.68). These findings warrant attention to this cardiovascular risk factor in apparently healthy adults.

Assessment of the association between serum uric acid levels and the incidence of hypertension in nonmetabolic syndrome subjects: A prospective observational study

The purpose of this study was to examine the association between serum uric acid (sUA) and the incidence of hypertension in nonmetabolic syndrome (non-MetS) subjects.This was a prospective observational study including 23,525 subjects who had been followed up for at least 5 years. A logistic regression model was used to assess independent risk factors associated with hypertension. An area under the receiver operating characteristic curve (auROC) was generated, and a nomogram was developed to assess diagnostic ability of sUA and the sUA-based score.We enrolled 11,642 subjects, and 763 (6.55%) were diagnosed with hypertension at the 5-year follow-up. Subjects were classified into 4 groups based on the sUA quarter. Using Q1 as the reference group, Q2, Q3, and Q4 were found to show a higher risk for the development of hypertension with odds ratio of 1.51 (1.15, 1.98), 1.72 (1.30, 2.27), and 2.27 (1.68, 3.06), respectively (P < .001) after adjusting for other known confounding variables. Interaction analysis showed that there was no significant difference between subgroups stratified on the basis of sex, age, body mass index, fasting plasma glucose, and high-density lipoprotein cholesterol except triglycerides (P = .006). The auROCs for sUA and the sUA-based score were 0.627 (0.607, 0.647) and 0.760 (0.742, 0.777), respectively. A nomogram comprising independent risk factors was developed to predict the 5-year risk of hypertension for each subject.High sUA was significantly associated with the incidence of hypertension in non-MetS subjects adjusting for confounders.

The problem of cardio-renal diseases in patients with gout

BACKGROUNDS

Although evidence is mounting on the role of hyperuricemia in cardio-renal disease, continuing doubt remains as to whether hyperuricemia can be considered a major causal cardiovascular risk factor. In addition, available data suggest that treatment may be beneficial, even in the absence of overt gout, when hyperuricemia accompanies other clinical conditions, such as urate deposition, advanced chronic kidney disease, or cardiovascular risk factors.

METHODS AND RESULTS

Analysis of the literature suggests there would be sufficient evidence warranting clinical trials to determine whether lowering uric acid levels would be clinically beneficial in the prevention or treatment of cardiovascular and renal diseases.

CONCLUSION

Under a practical profile, it becomes progressively more important to investigate the possibility of reducing serum uric acid levels in the general population below the level of 5.0 mg/dL.