Serum uric acid concentration and asymptomatic hyperuricemia with subclinical organ damage in general population

Gender Influence on XOR Activities and Related Pathologies: A Narrative Review

Taking into account the patient's gender is the first step towards more precise and egalitarian medicine. The gender-related divergences observed in purine catabolism and their pathological consequences are good examples of gender medicine differences. Uric acid is produced by the activity of xanthine oxidoreductase (XOR). The serum levels of both XOR activity and uric acid differ physiologically between the genders, being higher in men than in women. Their higher levels have been associated with gout and hypertension, as well as with vascular, cardiac, renal, and metabolic diseases. The present review analyzes the gender-related differences in these pathological conditions in relation to increases in the serum levels of XOR and/or uric acid and the opportunity for gender-driven pharmacological treatment.

Association Between Serum Uric Acid and Abdominal Aortic Calcification in Adults Aged 40 to 80 years: A Retrospective Cross-Sectional Study

There are numerous causes of abdominal aortic calcification (AAC), among which the relationship between serum uric acid and AAC still needs to be investigated further. The aim of this research was to ascertain whether serum uric acid is correlated with AAC. Our study included 3007 participants. We described the study population characteristics and utilized univariate analysis, stratified analysis, multiple equation regression analysis, smoothed curve fitting, and threshold effects analysis. AAC Total 24 score is used to reflect the range of aortic calcification at each vertebral level. As serum uric acid increased, the AAC Total 24 score first decreased and then increased. The fold point is located when serum uric is at 3.5 mg/dL. After adjusting for 16 covariates, the beta values for the groups with moderate and high serum uric acid levels were 0.34 and 0.53, respectively, compared with the low serum uric acid tertile group (P < .05). Our research indicates a negative correlation between serum acid level and AAC when serum uric acid <3.5 mg/dl, but it is positively correlated with the formation of AAC when serum uric acid >3.5 mg/dl.

Hyperuricemia as a Risk Factor in Hypertension among Patients with Very High Cardiovascular Risk

Hypertension remains a global threat to public health, affecting the worldwide population. It is one of the most common risk factors for cardiovascular disease. Today's treatments focus on creating a hypotensive effect. However, there is a constant search for additional factors to reduce the potential of developing hypertension complications. These factors may act as a parallel treatment target with a beneficial effect in specific populations. Some studies suggest that uric acid may be considered such a factor. This study investigated the potential effect of uric acid concentrations over 5 mg/dL on the incidence of hypertension complications among patients with very high cardiovascular risk. A total of 705 patients with hypertension and very high cardiovascular risk were selected and included in the analysis. The patients were divided and compared according to serum uric acid levels. The study showed a higher occurrence of heart failure (OR = 1.7898; CI: 1.2738-2.5147; p = 0.0008), atrial fibrillation (OR = 3.4452; CI: 1.5414-7.7002; p = 0.0026) and chronic kidney disease (OR = 2.4470; CI: 1.3746-4.3558; p = 0.0024) among individuals with serum uric acid levels over 5 mg/dL, males and those with a BMI > 25 kg/m2. These findings suggest that even serum uric acid concentrations over 5 mg/dL may affect the prevalence of hypertension-related complications among patients with very high cardiovascular risk.

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.

Modifiable risk factors for carotid atherosclerosis: a meta-analysis and systematic review

Background

Carotid atherosclerosis is a major cause of stroke, but the conclusion about risk factors for carotid atherosclerosis is still controversial. The aim of our present meta-analysis and systematic review was to explore the modifiable risk factors for carotid atherosclerosis.

Methods

We searched PubMed from January 1962 to October 2018 to include longitudinal and cross-sectional studies. The results were pooled using random effects model. Heterogeneity was measured by I² statistic and publication bias was assessed by funnel plots.

Results

A total of 14,700 articles were screened, of which 76 with 27 factors were eligible. Our meta-analysis of cross-sectional studies indicated nine factors (hyperlipidemia, hyperhomocysteinemia, hypertension, hyperuricemia, smoking, metabolic syndrome, hypertriglyceridemia, diabetes, and higher low density lipoprotein) were significantly associated with the presence of carotid plaque, among which four (hyperlipidemia, hyperhomocysteinemia, hypertension, and hyperuricemia) could elevate the risk of atherosclerosis by at least 50%; and one factor (hypertension) was associated with increased carotid intima-media thickness. In the systematic review, another five factors [negative emotion, socioeconomic strain, alcohol, air pollution, and obstructive sleep apnea syndrome (OSAS)] were also related to the presence of atherosclerosis. The cross-sectional associations with most of the above 14 factors were further confirmed by longitudinal studies. Among them, the managements of 4 factors (hypertension, hyperlipidemia, diabetes and OSAS) were indicated to prevent carotid atherosclerosis by cohort studies.

Conclusions

Effective interventions targeting pre-existing disease, negative emotion, lifestyle and diet may reduce the risk of carotid atherosclerosis. Further good-quality prospective studies are needed to confirm these findings.

Male asymptomatic hyperuricemia patients display a lower number of NKG2D+ NK cells before and after a low-purine diet

BACKGROUND

Aberrant activation of the immune system has been reported in asymptomatic hyperuricemia (HUA) patients. However, very few studies have elucidated the role of natural killer (NK) cells in this disease.

METHODS

In this study, we evaluated the relationship between NK cells and HUA in 16 control subjects and 20 patients, who were all on a low-purine diet. We analyzed the number of circulating NK cells, its subsets, interferon-γ, and CD107 NK cells, by flow cytometry, before and after 4 and 24 weeks of diet control. We also assessed the potential association of the NK cells with clinical measures.

RESULTS

The patients consistently had a lower number of NKG2D NK cells before and after low-purine diet, even the serum uric acid (SUA) levels <7 mg/dL after diet control. Moreover, a lower number of NK cells and a higher number of CD107a NK cells were observed on recruitment. Low-purine diet was benefit on the improvement of the SUA levels, body mass index (BMI), and the number and functions of NK cells. Furthermore, the number of CD3CD56 NK cells and NKG2D NK cells negatively correlated with the BMI before and after diet control.

CONCLUSION

The consistent lower number of NKG2D NK cells and correlated with BMI before and after low-purine diet may be involved in the occurrence and development of HUA.

Serum Uric Acid Is Independently Associated with Coronary Calcification in an Asymptomatic Population

Detecting early-stage atherosclerosis is an important step towards cardiovascular disease prevention. Coronary artery calcium (CAC) score is a sensitive and non-invasive tool for detecting coronary atherosclerosis. Higher serum uric acid (SUA) levels are known to be associated with cardiovascular diseases. However, there is inconsistency regarding the independence of the association. The aim of our study was to assess the association of CAC and SUA in an asymptomatic population. CAC scans of 281 participants were analyzed in a voluntary screening program. A health questionnaire, physical examination, and laboratory tests were also performed. Participants with a history of cardiovascular disease were excluded from the analysis. 36.3% (n = 102) of the participants had no detectable CAC and 13.9% (n = 39) had a CAC score of > 300. SUA showed positive correlation with CAC score (0.175, p < 0.01). SUA was independently associated with Ca score > 300 (OR 5.17, p = 0.01) after the effects of conventional risk factors were eliminated.

Relationship between Serum Uric Acid and Vascular Function and Structure Markers and Gender Difference in a Real-World Population of China-From Beijing Vascular Disease Patients Evaluation Study (BEST) Study

AIM

The study was done to establish the relationship between serum uric acid (UA) and vascular function and structure parameters including carotid femoral pulse wave velocity (CF-PWV), carotid radial pulse wave velocity (CR-PWV), cardio ankle vascular index (CAVI), ankle brachial index (ABI), and carotid intima-media thickness (CIMT), and the gender difference in a real-world population from China.

METHODS

A total of 979 subjects were enrolled (aged 60.86±11.03 years, male 416 and female 563). Value of UA was divided by 100 (UA/100) for analysis.

RESULTS

Body mass index (BMI), diastolic blood pressure (DBP), fasting plasma glucose (FPG), UA, and UA/100 were significantly higher in males compared with females (all p＜0.05); pulse pressure (PP), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) were lower in males than females (all p＜0.05). All vascular parameters including CF-PWV, CR-PWV, CAVI, ABI, and CIMT were higher in males than females (all p＜0.05). Multiple linear regression analysis showed that UA/100 was independently positively linearly correlated with CAVI (B=0.143, p=0.001) and negatively correlated with ABI in the male population (B=－0.012, p=0.020). In people with higher UA, the risk of higher CF-PWV was 1.593 (p＜0.05).

CONCLUSIONS

1. All vascular parameters were higher in males than females. There was no gender difference in the relationship between UA and vascular markers except in ABI. 2. UA was independently linearly correlated with CAVI. 3. In people with higher UA level, the risk of higher CF-PWV increased. Therefore, higher UA may influence the vascular function mainly instead of vascular structure.

Asymptomatic hyperuricemia is independently associated with coronary artery calcification in the absence of overt coronary artery disease: A single-center cross-sectional study

Recently, the pathogenic role of uric acid (UA) in both systemic metabolic and atherosclerotic diseases has been investigated. We sought to determine the independent correlation between serum UA levels and coronary artery calcification, as a marker of subclinical atherosclerosis. A total of 4188 individuals without prior coronary artery disease or urate-deposition disease were included. All of the participants underwent multidetector computed tomography (MDCT) for the evaluation of coronary artery calcification (CAC) during their health check-ups. The subjects were divided into thre groups according to CAC scores (group 1: 0; group 2: 1-299; group 3: ≥300). After controlling for other confounders, serum UA levels were found to be positively associated with increasing CAC scores (P = 0.001). Adjusted mean serum UA levels in each CAC group were estimated to be 5.2 ± 0.1 mg/dL, 5.3 ± 0.1 mg/dL, and 5.6 ± 0.2 mg/dL from groups 1, 2, and 3, respectively. Subsequent subgroup analyses revealed that this positive association was only significant in participants who were male, relatively older, less overweight, and did not have diabetes mellitus (DM), hypertension, smoking history, or renal dysfunction. In conclusion, serum uric acid levels were independently associated with CAC score severity and this finding is particularly relevant to the subjects who were male, relatively older, less overweight (body mass index < 25 kg/m), and without a history of DM, hypertension, smoking, or renal dysfunction.

Uric Acid, Vascular Stiffness, and Chronic Kidney Disease: Is There a Link?

Controversy exists with regard to the causal role of hyperuricemia in chronic kidney disease. Vascular stiffness may be the link that explains the relation between hyperuricemia and kidney disease. Hyperuricemia is associated with a number of effects on the vascular endothelium and vascular smooth muscle cells, including an increase in oxidative stress, production of vasoconstrictors, and changes on the structural properties of the large artery wall. Observational evidence in large epidemiological cross-sectional studies suggests that there is an independent association between uric acid and arterial stiffness. The limited evidence from cohort studies or clinical trials does not support treatment of hyperuricemia to reduce vascular stiffness in order to prevent kidney disease. Nevertheless, vascular stiffness may be a valid, reproducible, and useful surrogate endpoint. At this point there seems to be sufficient evidence to warrant larger clinical trials to determine whether lowering uric acid concentrations would be useful for prevention or treatment of vascular stiffness and, subsequently, of cardiovascular and kidney diseases. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=452726.

The Relation of Moderate Alcohol Consumption to Hyperuricemia in a Rural General Population

Background: although alcohol abuse is known to increase serum uric acid, the relation between moderate drinking and uric acid have remained poorly understood. We performed this study to evaluate whether different alcohol consumption level has different effects on the risk of hyperuricemia based on a rural general population. Method: multi-stage cluster sampling method was used to select a representative sample of individuals aged 35 years or older. Participants were asked to provide information about their alcohol consumption. Data regarding the demographic and lifestyle characteristics and the blood biochemical indexes of these participants were collected by well-trained personnel. Results: in total, 11,039 participants aged 35 years or older were included (4997 men and 6042 women). The prevalence of hyperuricemia in the different male alcohol consumption groups was 11.9% in non-drinkers, 12.6% in moderate drinkers, and 16.3% in heavy drinkers (p < 0.001). In females, the rates were 6.3% in non-drinkers, 8.1% in moderate drinkers, and 6.6% for heavy drinkers (p = 0.818). In males, multivariate logistic regression analyses shows heavy drinkers had an approximately 1.7-fold higher risk of hyperuricemia (OR: 1.657, 95% CI: 1.368 to 2.007, p < 0.001) than non-drinkers; moderate drinkers did not experience a significant increase in risk (OR: 1.232, 95% CI: 0.951 to 1.596, p = 0.114)). Multivariate logistic regression analyses of females showed that, compared with non-drinkers, neither moderate nor heavy drinkers had a significantly increased risk of hyperuricemia (OR: 1.565, 95% CI: 0.521 to 4.695, p = 0.425 for heavy drinkers; OR: 0.897, 95% CI: 0.117 to 6.855, p = 0.916 for moderate drinkers). Conclusions: heavy alcohol consumption increased the risk of hyperuricemia for males but not for females. Among both males and females, moderate alcohol consumption did not increase the risk of hyperuricemia.

Prevalence of hyperuricemia among Beijing post-menopausal women in 10 years

OBJECTIVES

The objective of this study was to explore the trend and risk factors of the prevalence of hyperuricemia among post-menopausal women in Beijing over a ten years period.

METHOD

This research was based on two cross-sectional surveys in post-menopausal women in Beijing. A total of 1881 post-menopausal women were included. Subjects answered a questionnaire and underwent a physical examination and blood test. Serum uric acid >357 μmol/L was diagnosed as hyperuricemia, and another diagnosis criterion (serum uric acid >416 μmol/L) was applied in these women.

RESULTS

Serum uric acid levels and hyperuricemia prevalence increased remarkably in the 10-year period. The prevalence of hyperuricemia increased more than 2-fold after being adjusted by age. Multivariate logistic regression models revealed hyperuricemia associated with age, education level, urban residents, alcohol consumption, hypertension, obesity, and dyslipidemia. With the increasing number of traditional cardiovascular risk factors (including hypertension, obesity, diabetes, and dyslipidemia), the risk of hyperuricemia increased significantly, and the accumulative effect of the factors on the risk of hyperuricemia was determined.

CONCLUSION

The prevalence of hyperuricemia was high and exhibited a remarkable, increasing trend in Beijing community-based, post-menopausal women. Better management of relative factors could help to prevent further increases in the burden of hyperuricemia in post-menopausal women in this region.

The Role of Monitoring Arterial Stiffness with Cardio-Ankle Vascular Index in the Control of Lifestyle-Related Diseases

Arteriosclerosis is a major contributor to cardiovascular diseases. One of the difficulties in controlling those diseases is the lack of a suitable indicator of arteriosclerosis or arterial injury in routine clinical practice. Arterial stiffness was supposed to be one of the monitoring indexes of arteriosclerosis. Cardio-ankle vascular index (CAVI) is reflecting the stiffness of the arterial tree from the origin of the aorta to the ankle, and one of the features of CAVI is independency from blood pressure at a measuring time. When doxazosin, an α1-adrenergic blocker, was administered, CAVI decreased, indicating that arterial stiffness is composed of both organic stiffness and functional stiffness, which reflects the contraction of arterial smooth muscle. CAVI shows a high value with aging and in many arteriosclerotic diseases, and is also high in persons possessing main coronary risk factors such as diabetes mellitus, metabolic syndrome, hypertension and smoking. Furthermore, when the most of those risk factors were controlled by proper methods, CAVI improved. Furthermore, the co-relationship between CAVI and heart function was demonstrated during treatment of heart failure. This paper reviews the principle and rationale of CAVI, and discusses the meaning of monitoring CAVI in following up so-called lifestyle-related diseases and cardiac dysfunction in routine clinical practice.

[Cardiovascular screening programme in the Central Hungarian region. The Budakalász Study]

INTRODUCTION

The reduction in mortality due to prevention programmes observed in some European countries is not currently reached in Hungary. Effective prevention is based on the screening of risk factors and health state of the population.

AIM

The goal of this study was to develop a longitudinal, population-based screening programme in the Central Hungarian region in order to collect information on the health state and cardiovascular risk profile of the citizens and discover new potential cardiovascular risk factors.

METHOD

The Budakalász Study is a self-voluntary programme involving the adult population (>20 yrs, approx. 8000 persons), and it consists of questionnaires, non-invasive tests (anthropometry, cardiac echo, carotid duplex scan, blood pressure measurement, ankle-brachial index), venous blood sample collection and laboratory tests.

RESULTS

Until January, 2014, 2420 persons (30% of the population, male: 41.2%, average age 54.8 years) participated in the programme. Cardiovascular morbidity was higher in contrast to a former national survey. The number of risk factors and, therefore, 10-year cardiovascular risk were also elevated in this population.

CONCLUSIONS

These findings underline the importance of screening programmes and effective therapies.