Metabolic syndrome, diabetes, and hyperuricemia. Curr Opin Rheumatol. 2013;25:210-216. [PMID: 23370374 DOI: 10.1097/bor.0b013e32835d951e]

Therapeutic effects and mechanisms of N-(9,10-anthraquinone-2-ylcarbonyl) xanthine oxidase inhibitors on hyperuricemia

Objective: To observe the antioxidative effects of N-(9,10-anthraquinone-2-ylcarbonyl) xanthine oxidase inhibitors (NAY) in vitro and in vivo models of hyperuricemia and explore the mechanism.

Methods: A classical experimental method of acute toxicity and a chronic toxicity test were used to compare the toxic effects of different doses of NAY in mice. The hyperuricemia mouse model was established by gavage of potassium oxonate in vivo. After treatment with different doses of NAY (low dose: 10 mg/kg, medium dose: 20 mg/kg, and high dose: 40 mg/kg) and allopurinol (positive drug, 10 mg/kg), observe the levels of uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) in urine and serum, respectively, and detect the activities of xanthine oxidase in the liver. The hyperuricemia cell model was induced by adenosine and xanthine oxidase in vitro. The cells were given different doses of NAY (50, 100, and 200 μmol/L) and allopurinol (100 μmol/L). Then the culture supernatant UA level of the medium was measured. The next step was to detect the xanthine oxidase activity in the liver and AML12 cells, and the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammatory factors in the kidney and serum of mice. Western blot was used to detect xanthine oxidase protein expression in mouse liver tissue and AML12 cells, ASC, Caspase-1, NLRP3, GLUT9, OAT1, and OAT3 protein expression in mouse kidney tissue and HK-2 cells. Hematoxylin–eosin staining was used to stain the liver and kidney tissues of mice and observe the tissue lesions.

Results: NAY had little effect on blood routine and biochemical indexes of mice, but significantly reduced the serum UA level. NAY significantly reduced the level of UA in hyperuricemia mice and cells by inhibiting xanthine oxidase activity and reduced the levels of TNF-α, IL-6, and other inflammatory factors in serum and kidney of mice. NAY can inhibit inflammation by inhibiting the NLRP3 pathway. In addition, NAY can downregulate GLUT9 protein expression and upregulate OAT1 and OAT3 protein expression to reduce the UA level by promoting UA excretion and inhibiting UA reabsorption.

Conclusion: These findings suggested that NAY produced dual hypouricemic actions. On the one hand, it can inhibit the formation of UA by inhibiting xanthine oxidase inhibitors activity, and on the other hand, it can promote the excretion of UA by regulating the UA transporter. It provides new ideas for the development of hyperuricemia drugs in the future.

The Additive Values of the Classification of Higher Serum Uric Acid Levels as a Diagnostic Criteria for Metabolic-Associated Fatty Liver Disease

Serum uric acid (SUA) is regarded as an independent risk factor for nonalcoholic fatty liver disease (NAFLD). However, the role of SUA in the new diagnosis flowchart of metabolic-associated fatty liver disease (MAFLD) remains unclear. A cross-sectional study enrolled consecutive individuals with ultrasonography and magnetic resonance imaging−based proton density fat fraction (MRI-PDFF) measurements in the First Affiliated Hospital of Sun Yat-sen University from January 2015 to December 2021. All patients were divided into four groups according to their baseline SUA levels and sex. Of the 3537 ultrasound-diagnosed and 1017 MRI-PDFF-diagnosed MAFLD patients included, the prevalence of severe steatosis determined with ultrasound or MRI-PDFF increased across the serum SUA quartiles. The SUA cutoffs were identified as ≥478 µmol/L and ≥423.5 µmol/L for severe steatosis in male and female MAFLD, respectively. Furthermore, using these cutoff values, patients with higher SUA levels in the NAFLD−non-MAFLD group had higher liver fat contents than those without (16.0% vs. 9.7%, p < 0.001). The lean/normal-weight NAFLD−non-MAFLD patients with higher SUA levels are still at high risk of severe steatosis. This study supports the rationale for SUA being established as another risk factor for metabolic dysfunctions in lean/normal-weight MAFLD.

Association Between the Risk of Hyperuricemia and Changes in Branched-Chain Amino Acids Intake Over Twelve Years: A Latent Class Trajectory Analysis From the China Health and Nutrition Survey, 1997-2009

Objective

This study aims to identify dietary branched-chain amino acids (BCAA) consumption trajectories in Chinese adults and to evaluate their association with the risk of hyperuricemia (HU).

Methods

Cohort data from the China Health and Nutrition Survey 1997–2009 were adopted in this research. A total of 6,810 participants aged ≥18 years were included in this study. Participants were designated into four subgroups on basis of the trajectories of dietary BCAA consumption. Cox proportional hazards models were performed to discuss the relationships between varied trajectories and the risk of HU after adjusting potential confounders. The intermediary effect of differential blood indexes between the trajectories and the risk of HU was explored with mediation analysis.

Results

Four distinct trajectory groups of dietary BCAA consumption were identified. Compared with the low stable trajectory group, high to low trajectory group was greatly related to an increased risk of HU (HR 1.35 (95% CI 1.03 to 1.79)) with modification for covariates. Total cholesterol (TC), hemoglobin A1c (HbA1c), fasting blood glucose (FBG), and triglyceride (TG) partially regulated trajectories and HU.

Conclusion

Gradually decreasing dietary BCAA intake increased the risk of HU, which is, at least, partially mediated by TC, HbA1c, FBG, and TG levels.

Clinical Effect of the Guizhi Shaoyao Zhimu Decoction in the Treatment of Hyperuricemia

Traditional Chinese Medicine (TCM) is a medical system with a distinctive theoretical framework and extensive experience in identification and treatment acquired by the Chinese people in long-term medical practice and life practice. It is a complete, integrated, and complex knowledge system in epistemology. This study is aimed at exploring the clinical effectiveness of TCM called the Guizhi Shaoyao Zhimu Decoction in the treatment of hyperuricemia. A total of 100 patients with hyperuricemia at the Medical College of the Second Clinical College, Shandong, China, from January 2019 to January 2022 are selected as the research subjects and divided into group A and group B according to the random table method, with 50 cases in each group. Group A is treated with oral allopurinol tablets, 100 mg, 2 times a day, and group B is treated with the modified Guizhi Shaoyao Zhimu Decoction based on group A. For observation, serum uric acid (SUA) levels, urinary uric acid (UUA) levels, levels of serum inflammatory response factors (IL-6, CRP, and TNF-α), vascular endothelial function indexes (serum malondialdehyde (MDA) content, nitric oxide (NO) content), an acute attack of gout, and the incidence of adverse reactions are measured. Results show that after 2 w and 4 w of treatment, the levels of blood uric acid in each group gradually decreased compared with those before treatment, and group B is lower than group A (P < 0.05). After treatment, the vascular endothelial function indexes and inflammatory factor levels in each group are significantly improved compared with those before treatment, and the indexes in group B are better than those in group A. There is no significant difference in the incidence of related adverse reactions and acute attack of gout (P > 0.05). This shows that the TCM Guizhi Shaoyao Zhimu Decoction has a significant curative effect in the treatment of patients with hyperuricemia, which is worthy of clinical reference application.

Serum Uric Acid Levels and Nonalcoholic Fatty Liver Disease: A 2-Sample Bidirectional Mendelian Randomization Study

BACKGROUND

Observational studies have shown that nonalcoholic fatty liver disease (NAFLD) is highly correlated with serum uric acid (SUA). However, these studies have an inherent risk of bias due to reverse causality. Here, we perform a Mendelian randomization (MR) study to investigate causality between SUA and NAFLD.

METHODS

We performed a 2-sample bidirectional MR analysis using summary-level data from genome-wide association studies of SUA (with up to 110 347 individuals) and NAFLD (1483 cases and 17781 controls) in European populations. First, 13 single nucleotide polymorphisms (SNPs) associated with SUA were selected as instruments to estimate the causal effect of elevated SUA levels on the risk of NAFLD using the inverse-variance weighted (IVW) method. Then we performed MR with 3 SNPs as genetic instruments for NAFLD. To test the reliability, further sensitivity analyses were also conducted.

RESULTS

Our MR analyses demonstrated that NAFLD was associated with SUA levels (β = 0.032, P = 0.003). Similar results were obtained using other MR methods and in sensitivity analyses. Genetic predisposition to elevated SUA levels was not associated with NAFLD (IVW MR, odds ratio = 1.02, 95% CI: 0.90-1.15, P = 0.775). Similar results were obtained using other 4 pleiotropy robust MR methods and in sensitivity analyses, excluding 9 SNPs associated with potential confounders.

CONCLUSIONS

Our study supports the causal increased SUA levels by NAFLD, while our study does not confirm a causal association for SUA levels on risk of NAFLD. Further study is needed to interpret the potential mechanisms.

Dose-Response Relationship of Uric Acid With Fasting Glucose, Insulin, and Insulin Resistance in a United States Cohort of 5,148 Non-diabetic People

Background

There is a limited number of studies on the dose-response relationship between serum uric acid and impaired glucose metabolism in people without diabetes, and no large-scale research exploring the relationship in women without diabetes is based on menopausal status. Consequently, the present study aimed to investigate the above relationship in United States adults without diabetes.

Materials and Methods

Data from 2,498 men and 2,650 women aged ≥20 years were obtained from the National Health and Nutrition Examination Survey 2011-2016 conducted in the United States. Binary logistic regression analysis was applied to evaluate the association between uric acid and impaired glucose metabolism. Restricted cubic spline analysis, sensitivity analysis, and stratified analysis by menopausal status were performed to explore the above relationships.

Results

A positive correlation was found between uric acid and the risk of insulin resistance in all participants (P < 0.05). In binary logistic regression analysis, after adjusting for confounding factors, compared with the lowest quartile of uric acid, the odds ratio (95% confidence intervals) of insulin resistance in the highest quartile was 1.9 (1.1-3.1) and 2.2 (1.2-4.3) in men and women, respectively. A significant positive relationship was also observed between uric acid and impaired fasting glucose and hyperinsulinemia in women, while in men, uric acid was positively associated with the risk of hyperinsulinemia but not impaired fasting glucose. Restricted cubic spline showed that the odds ratios of insulin resistance and hyperinsulinemia increased with elevating uric acid levels in both men and women. When stratified by menopause, the association remained significant in pre-menopausal women aged ≥20, but insignificant in post-menopausal women.

Conclusion

Uric acid was positively associated with the risk of impaired glucose metabolism in a cohort of United States adults, and uric acid increased the risk of insulin resistance in pre-menopausal, but not in post-menopausal women.

Prevalence and risk factors of hyperuricaemia in non-obese Chinese: a single-centre cross-sectional study

OBJECTIVES

Hyperuricaemia is closely related to metabolic diseases and is receiving increasing attention from all over the world. This study aimed to investigate the prevalence and factors associated with hyperuricaemia in non-obese Chinese population.

DESIGN

Retrospective cross-sectional study.

SETTING

A large general hospital that can provide health check-ups in Hangzhou, China.

PARTICIPANTS

A total of 5731 apparently healthy Chinese adults (2349 men and 3382 women) who took their health check-ups during the year of 2019.

EXCLUSION CRITERIA

(1) those with body mass index ≥24 kg/m2; (2) those with incomplete anthropometric and biochemical data; (3) those with a history of malignancy and (4) those under urate-lowering treatment.

PRIMARY AND SECONDARY OUTCOME MEASURES

The prevalence and factors associated with hyperuricaemia in non-obese Chinese adults.

RESULTS

Of the 5731 non-obese subjects enrolled, 538 (9.4%) were identified as having hyperuricaemia, specifically 16.3% in men and 4.6% in women. The prevalence of hyperuricaemia markedly increased in women aged above 50 years. The prevalence of hyperuricaemia was significantly higher in metabolically unhealthy participants with normal weight than in metabolically healthy participants with normal weight. Participants with hyperuricaemia showed a higher prevalence of metabolic syndrome and fatty liver disease than participants with normouraemia. Age, waist circumference, estimated glomerular filtration rate, blood urea nitrogen, excessive drinking and fatty liver were associated with hyperuricaemia in both genders.

CONCLUSION

The prevalence of hyperuricaemia was 9.4% in non-obese Chinese adults. Non-obese participants with hyperuricaemia also showed multiple metabolic disorders. We suggest that clinicians pay attention to serum uric acid level in non-obese patients.

Autophagy protects against high uric acid-induced hepatic insulin resistance

Uric acid (UA), the end-product of purine metabolism, is closely related to hepatic insulin resistance (IR). Autophagy is a conserved intracellular degradation process maintaining cellular homeostasis. Autophagy plays a protective role in obesity-related hepatic IR, but whether it occurs in high uric acid (HUA)-induced hepatic IR is unclear. In this study, spontaneously elevated UA level induced hepatic IR and facilitated hepatic autophagy degradation in uricase knockout (Uox^-/-) mice. In vitro, HepG2 cells stimulated with HUA medium showed decreased glucose uptake and inhibition of insulin signaling pathways, concomitant with activation of autophagy, as manifested by increased conversion of LC3B-I to -II. Rapamycin, the autophagy activator, alleviated but the autophagy inhibitor trimethyl adenine (3-MA) aggravated HUA-induced IR in HepG2 cells. Similarly, rapamycin ameliorated and 3-MA worsened HUA-induced blood glucose level and hepatic IR in Uox^-/- mice. Mechanistically, HUA enhanced AMPKα phosphorylation (p-AMPKα) and inhibited mammalian target of rapamycin phosphorylation (p-mTOR) in HepG2 cells. The levels of p-AMPKα and LC3B-II/I were downregulated in HepG2 cells transfected with small interfering RNA (siRNA) against AMPKα, which suggests that the AMPKα-mTOR pathway was involved in HUA-induced autophagy. Antioxidant N-acetyl-L-cysteine reversed elevated reactive oxygen species levels induced by HUA in HepG2 cells, and AMPKα level was also inhibited, which suggests that AMPKα activation may be derived from reactive oxygen species. Collectively, these findings demonstrate that HUA increased hepatic autophagy, and autophagy activation plays a protective role in hepatic IR, which may suggest a potential therapeutic target for hepatic IR derived from HUA.

Efficacy of Xanthine Oxidase Inhibitors in Lowering Serum Uric Acid in Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Objective: Current guidelines for gout recommend a treat-to-target approach with serum uric acid (SUA). However, there is little evidence for the dose-dependent effects of urate-lowering therapy (ULT). Herein, we analyzed the reported SUA-lowering effect and SUA target achievement differences for various doses of xanthine oxidase inhibitors. Methods: Approved ULT drugs were selected from the FDA Drug Database. We included prospective randomized controlled trials of ULT drugs from ClinicalTrials.gov, articles published in the journal “Drugs”, and Embase, a literature database. A meta-analysis was performed to determine the ability of different ULT drugs and doses to lower and maintain a target SUA < 6 mg/dL. Results: We identified 35 trials including 8172 patients with a baseline SUA of 8.92 mg/dL. The allopurinol, febuxostat, and topiroxostat showed dose-proportional SUA-lowering responses. Compared with allopurinol 300 mg daily, febuxostat 80 mg daily and 120 mg daily more effectively maintained SUA < 6 mg/dL. Conclusion: Allopurinol, febuxostat, and topiroxostat showed dose-proportional ability to lower and achieve a target SUA < 6 mg/dL. Significance and Innovations. We showed dose-dependent SUA lowering effects of allopurinol, febuxostat, and topiroxostat. Febuxostat is effective at ULT compared to allopurinol and could be potentially offered as an alternative agent when patients (1) have CKD, (2) have the human leukocyte antigen HLA-B*5801 allele, and (3) become refractory to allopurinol. Gradual allopurinol dose increase with a lower starting dose is needed in CKD.

Hepatic Steatosis Is Associated with High White Blood Cell and Platelet Counts

The incidence of hepatic steatosis is increasing globally, and it is important to identify those at risk to prevent comorbidities. Complete blood count is a simple, convenient, and inexpensive laboratory examination which can be used to obtain white blood cell (WBC) and platelet counts. The aims of this study were to investigate the relationships between WBC and platelet counts with hepatic steatosis, and whether WBC and platelet counts were associated with the severity of hepatic steatosis. We enrolled 1969 participants residing in southern Taiwan who took part in a health survey from June 2016 to September 2018 in this cross-sectional study. None of the participants were heavy alcohol users or had a history of hepatitis B or C. We collected laboratory data, and the severity of hepatic steatosis was determined by abdominal ultrasound. The overall prevalence rate of hepatic steatosis was 42.0%. There were significant trends of stepwise increases in WBC count (p < 0.001) corresponding to the severity of hepatic steatosis. After multivariable linear regression analysis, hepatic steatosis was significantly associated with high WBC count (coefficient β, 0.209; 95% confidence interval (CI), 0.055 to 0.364; p = 0.008) and high platelet count (coefficient β, 12.213; 95% CI, 6.092 to 18.334; p < 0.001); also, higher WBC counts corresponded with the severity of hepatic steatosis.

Serum 25-hydroxyvitamin D might be negatively associated with hyperuricemia in U.S. adults: an analysis of the National Health and Nutrition Examination Survey 2007-2014

PURPOSE

The results of previous studies on the relationship between serum 25-hydroxyvitamin D [25(OH)D] and hyperuricemia are controversial. We hypothesized that serum 25(OH)D concentrations of U.S. adults would negatively correlate with the risk of hyperuricemia.

METHOD

Data came from the National Health and Nutrition Examination Survey 2007-2014 were used, after excluding those who met at least one of the exclusion criteria, a total of 9096 male individuals and 9500 female individuals aged 18 years or older were included. Binary logistic regression analysis and restricted cubic spline with fully adjusted confounding factors were applied to evaluate the association between serum 25(OH)D and hyperuricemia. We further performed stratified analysis and sensitivity analysis to minimize the influence of gender, metabolic syndrome, obesity and renal dysfunction on the above association.

RESULTS

We found a negative correlation between serum 25(OH)D and hyperuricemia. In the binary logistic regression analysis, compared with the highest serum 25(OH)D quartile [Q4: 25(OH)D > 77.10 nmol/L] group, the odds ratios (95% confidence intervals) in the lowest quartile [Q1: 25(OH)D ≤ 43.20 nmol/L] was 1.46 (1.22-1.75) in the fully adjusted model. Restricted cubic spline analysis showed L-shaped and non-linear relationships between 25(OH)D and hyperuricemia. In sensitivity analysis, after restricting to participants without significant renal dysfunction and obesity, the above association remained significant. After restricting to participants who were diagnosed as metabolic syndrome, above association remained significant in the fully adjusted model. In stratified analysis by gender, the association remained significant among males and females.

CONCLUSIONS

Serum 25(OH)D might be inversely associated with hyperuricemia in general U.S. adults. From our study, for people with unexplained hyperuricemia, screening for serum Vitamin D concentration might be necessary.

Elevated Uric Acid Mediates the Effect of Obesity on Hypertension Development: A Causal Mediation Analysis in a Prospective Longitudinal Study

Objective

Although elevated uric acid is associated with obesity and considered a predictor of hypertension, the causal linkage between the three metabolic conditions is not very clear. We aim to examine whether elevated uric acid mediates the effects of obesity on hypertension development.

Methods

A total of 1984 participants (mean aged 53 years, 62.10% female) with repeated measurements of obesity, blood pressure, and uric acid 4 years apart in the Gusu cohort were included. We first applied cross-lagged panel analysis and bidirectional association analysis to delineate the temporal association between obesity and hyperuricemia. Then, a causal mediation model was constructed to further examine the causal role of hyperuricemia in the linkage between obesity and hypertension. Age, sex, education, cigarette smoking, alcohol consumption, fasting blood glucose, and lipids were adjusted.

Results

The cross-lagged panel analysis demonstrated that the relationship from baseline obesity to follow-up hyperuricemia was stronger than that from baseline hyperuricemia to follow-up obesity (β: 0.09 vs 0.06, P<0.01 for BMI, β: 0.13 vs 0.07, P<0.01 for WC). Bidirectional association analysis found that baseline obesity predicted the risk of incident hyperuricemia (OR = 1.09, P<0.01 for BMI, OR = 1.05, P<0.01 for WC), but the other directional association was not statistically significant (all P>0.05). The causal mediation analysis found that hyperuricemia partially mediated the association of baseline BMI (mediate proportion: 3.09%, 95% CI: 0.97%~6.00% for SBP, 3.74%, 95% CI: 1.55%~7.00% for DBP) and baseline WC (mediate proportion: 5.56%, 95% CI: 2.01%~11.00% for SBP, 5.81%, 95% CI: 2.59%~10.00% for DBP) with follow-up blood pressures.

Conclusion

Obesity preceded hyperuricemia and the latter partially mediated the relationship between obesity and hypertension, independent of behavioral and other metabolic factors.

Association between serum uric acid with diabetes and other biochemical markers

Objective

This study aimed to decipher the association between serum uric acid (UA) and glycated hemoglobin (HbA1c) in the population from the southern region of Saudi Arabia.

Method

In this retrospective cross-sectional investigation, clinical data obtained from the different commercial laboratories in the Asir region of Saudi Arabia were screened over 2 years. Data were analyzed using standard statistical methods.

Results

A total of 1984 laboratory investigations with 1215 females (61.2%) and 769 males (38.6%) were included in the data analysis. In our investigation, the prevalence of hyperuricemia in the study population was 53.5% (41.2% females and 12.3% males) and in the diabetic population was 12.7% (9.47% females and 3.23% males), in prediabetics was 12.65% (9.8% females and 2.85% males), respectively. Prediabetic subjects had higher UA levels than people with diabetes or healthy people. Higher UA quartiles were associated with a high level of urea, blood urea nitrogen (BUN) creatinine, HbA1c, fasting blood sugar (FBS), and total cholesterol (TC) (P < 0.05). High UA (OR = 1.33 for diabetes; OR = 2.676 for prediabetes), high BUN (OR = 3.05 for diabetes; OR = 2.293 for prediabetes), high TC (OR = 3.75 for diabetes; OR = 1.098 for prediabetes), and high TG (OR = 2.67 for diabetes; OR = 1.943 for prediabetes) parameters are the most influential risk factor in diabetic and prediabetic patients than the people who have normal UA, BUN, TC, and TG value.

Conclusion

High UA levels are significantly associated with prediabetes as defined by HbA1c criteria, indicating that UA has a significant role in the disturbance of glucose metabolism. A significant positive association was observed between dyslipidemia and serum UA in the study population.

Postprandial Glycemic Dips Are Associated With Metabolic Disorders and CVD Risk in Euglycemic Individuals

CONTEXT

Metabolic disorders and cardiovascular disease (CVD) threaten human health. Many studies have assessed the phenomenon of metabolic disorders and CVD in patients with diabetes. However, in euglycemic individuals, the relationships between glucose regulation, metabolism, and CVD remain unclear.

OBJECTIVE

This work aimed to explore the associations between postprandial glucose dips, metabolic disorders, and CVD risk.

METHODS

We analyzed data from the Thyroid disorders, Iodine status and Diabetes Epidemiological survey (TIDE study), which included 38 878 euglycemic individuals from all 31 provinces of mainland China. The prevalence of metabolic disorders and their related components and CVD risk were calculated according to postprandial glucose dips. Logistic regression models of quartiles of postprandial glucose dips were used to further explore whether the prevalence of these disorders was associated with postprandial glucose dips.

RESULTS

Odds ratios for the fourth vs the first quartile of glucose dips were 0.59 (95% CI, 0.55-0.63) (P < .001) for metabolic disorders, 0.48 (95% CI 0.44-0.53) (P < .001) for metabolic syndrome (MetS), and 0.54 (95% CI, 0.50-0.59) (P < .001) for hyperuricemia. The odds ratio of a 10-year CVD risk greater than 20% for the fourth vs the first glucose dip quartile was 0.67 (95% CI, 0.52-0.85) (P < .001). Models adjusted for body mass index yielded similar results.

CONCLUSION

Postprandial glucose dips are associated with metabolic disorders, MetS and its related component diseases, and CVD risk. Glucose dips may be a marker of underlying metabolic abnormalities.

Uricase-deficient rats with similarly stable serum uric acid to human’s are sensitive model animals for studying hyperuricemia

The aim of this study was to provide a sensitive model animal for studying hyperuricemia. Male uricase-deficient rats, named Kunming-DY rats, were raised for 130 days, or orally administered with purines and other chemicals. Serum uric acid (SUA) in the animals was assayed, and the UA level in their organs and their 24-h excretion was determined. Genes in the jejunum, ileum, kidney and liver related to UA synthesis and transportation were detected by quantitative RNA sequencing. Uricase-deficient rats have a high level of SUA and are sensitive to xanthine, adenosine, inosine, allopurinol, and alcohol. Besides, the high level of SUA in male uricase-deficient rats was stable, much higher than that in wild-type rats but similar to that in men. The distribution pattern of UA in uricase-deficient rats’ organs was different from that in wild-type rats. The kidney, liver, and small intestine were the top three organs where UA distributed, but the UA in the small intestine, colon, lung, thymus, and brain was less affected by uricase deficiency, indicating that these organs are constitutive distribution organs in UA. The 24-h UA excreted by a uricase-deficient rat was about five times higher than that excreted by a wild-type rat. However, the 24-h UA excreted through feces was not significantly changed. Both the urine volume and UA in uricase-deficient rats significantly increased, and more than 90% of UA was excreted via urine. The expression of xanthine dehydrogenase was not upregulated. Some genes of transporter associated with uric acid excretion in the kidney were significantly regulated, though not sufficient to explain the increase in SUA. In conclusion, male uricase-deficient rats’ UA metabolism is similar to that of men. The elevation of SUA in uricase-deficient rats is caused by uricase deficiency, and uricase-deficient rats are a sensitive model for studying hyperuricemia.

Chemical Analysis of Eruca sativa Ethanolic Extract and Its Effects on Hyperuricaemia

In vivo assays and chemical analyses were performed on the ethanolic extract from leaves of Eruca sativa. UHPLC-ESI-QTOF analysis confirmed the presence of glucosinolates and flavonol glucosides. The major flavonoid of the ethanolic extract, kaempferol-3,4'-di-O-β-glucoside, was isolated, a HPLC-DAD method developed and validated to quantify its content in the extract. In vivo experiments were carried out on Wistar rats with hyperuricaemia induced by potassium oxonate and uric acid. A hypouricaemic effect was observed in hyperuricaemic Wistar rats treated with ethanolic extract at dose of 125 mg/kg and kaempferol-3,4'-di-O-β-glucoside at dose of 10 mg/kg. The main anti-hyperuricaemic mechanism observed in the extract was uricosuric. Kaempferol-3,4'-di-O-β-glucoside was identified as an important component responsible for the total activity of the ethanolic extract and was considered as a good chemical and biological marker of the ethanolic extract of E. sativa. The obtained results indicated the potential of E. sativa in the treatment of hyperuricaemia and its comorbidities.

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.

Non-alcoholic fatty liver disease: correlation with hyperuricemia in a European Mediterranean population

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) are two pathologies that intersect each other. It was found that there is an association between MetS/NAFLD and hyperuricemia. The aim of our study was to demonstrate this association in a European Mediterranean population.

METHODS

We compared 236 patients with NAFLD to 218 patients without NAFLD. We assessed laboratory metabolic parameters (serum uric acid - SUA, fasting glucose, triglycerides, total cholesterol, etc.) and the presence or absence of MetS in a retrospective, cross-sectional, case-control manner.

RESULTS

Analysis of the two main variables in study showed a moderate direct correlation (p< 0.01; Pearson coefficient 0.443) between SUA and NAFLD. Evaluation for SUA quartiles showed a decreased risk of NAFLD for the first and second quartiles (OR Q1 = 0.20; OR Q2 = 0.59), but increased for the third and fourth quartiles (OR Q3 = 2.22; OR Q4 = 6.97). In females, the risk of NAFLD was less compared to males for the first three quartiles of SUA, but it was more than double for the fourth quartile (OR Q1 0.21 vs 0.16; OR Q2 0.82 vs 0.45; OR Q3 2.50 vs 2.26; OR Q4 4.50 vs 9.83). In the NAFLD group, hyperuricemia was significantly correlated with sex, obesity, hypertension, and with the number of components of the MetS. In the Control group, SUA directly correlated with age, diabetes, and ALT, but not with obesity.

CONCLUSION

We have found a significant correlation between NAFLD and hyperuricemia. The higher SUA levels accompanied the risk of NAFLD.

Association between serum uric acid level and non-alcoholic fatty liver disease in Koreans

Background

The association between serum uric acid (SUA) levels and non-alcoholic fatty liver disease (NAFLD) is controversial.

Objectives

We compared the association of SUA levels with NAFLD, abnormal alanine transferase (ALT), and the degree of liver fibrosis to clarify the association of SUA levels with NAFLD.

Methods

We conducted a retrospective cross-sectional study. Adult patients who underwent a health check-up (N = 1,343) were included for analysis. Fatty liver was diagnosed by abdominal ultrasonography. The degree of liver fibrosis was determined using the NAFLD fibrosis score (NFS). Pearson correlation analysis showed a stronger correlation of SUA level with the fatty liver index (r = 0.40, P < 0.001) than the correlation with serum ALT level (r = 0.28, P < 0.001), or NFS (r = 0.018, P = 0.51). SUA levels in patients with NAFLD and an abnormal liver function test (LFT) result were significantly higher than levels in patients without NAFLD and abnormal LFT results. By contrast, there was no significant association of SUA level with NFS grade. When age, male sex, body mass index, the presence of hypertension, diabetic mellitus, and NAFLD, abnormality of ALT level, and SUA level were included in binary logistic regression to evaluate risk factors for elevated NFS grade, hyperuricemia was not significantly associated with NFS grade (OR = 0.94, P = 0.75).

Conclusion

Pearson correlation and logistic regression together indicated SUA level is more closely associated with hepatic steatosis than abnormal liver function test or hepatic fibrosis.

Impact of Combined Antiretroviral Therapy on Metabolic Syndrome Components in Adult People Living with HIV: A Literature Review

The development of metabolic derangements as a result of HIV treatment has been an important area of research since the introduction of zidovudine in the 1980's. Antiretroviral therapy has intensely evolved in the last three decades, with new drugs gradually incorporated into everyday clinical practice. With the life expectancy of people living with HIV rapidly approaching that of their HIV-negative counterparts, the influence of these antiretrovirals on the development of the components of the metabolic syndrome remains of major interest to clinicians and their patients. In this review, we aimed to discuss the impact of cART on components of the metabolic syndrome, i.e., weight, plasma lipid levels, plasma glucose levels, and blood pressure, describing the influence of cART classes and of individual antiretrovirals. We also aimed to outline the limitations of the research conducted to date and the remaining knowledge gaps in this area.

Association between vitamin D3 levels and insulin resistance: a large sample cross-sectional study

Previous studies have shown that vitamin D3 may be a potential factor in insulin resistance, but the relationship between vitamin D3 and insulin resistance still remains controversial. At present, more research is needed to explore the relationship between vitamin D3 and insulin resistance. The samples from 2009 to 2018 in NHANES database were analyzed to Investigate the relationship and the potential mechanism. We performed a cross-sectional study of five periods in the NHANES database. Finally, 9298 participants were selected through strict inclusion and exclusion criteria, Multivariate logistic regression analysis and curve fitting were conducted to explore the relationship between vitamin D3 level and insulin resistance. Moreover, subgroup analysis was used to further prove the association. The results revealed that there was a strong association between vitamin D3 and insulin resistance (OR 0.82, 95% CI 0.72-0.93). However, subgroup analyses indicated that this correlation varied between individuals and races. There was a negative correlation between vitamin D3 level and insulin resistance, which provides a new proof for exploring the influencing factors of insulin resistance. More well-designed studies are still needed to further elaborate on these associations.

Association between liver-type fatty acid-binding protein and hyperuricemia before and after laparoscopic sleeve gastrectomy

BACKGROUND

Liver-type fatty acid-binding protein (FABP1) contributes to metabolic disorders. However, the relationship between FABP1 and hyperuricemia remains unknown. We aimed to evaluate the correlation between serum FABP1 and hyperuricemia in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG).

METHODS

We enrolled 105 patients (47 men and 58 women) with obesity who underwent LSG. They were divided into two groups: normal levels of uric acid (UA) (NUA, n = 44) and high levels of UA (HUA, n = 61) with matching sexes. FABP1 levels and other biochemical parameters were measured at baseline and 3, 6, and 12 months after LSG.

RESULTS

Serum FABP1 levels were significantly higher in the HUA group than in the NUA group (34.76 ± 22.69 ng/mL vs. 25.21 ± 21.68 ng/mL, P=0.024). FABP1 was positively correlated with UA (r=0.390, P=0.002) in the HUA group. The correlation still existed after adjusting for confounding factors. Preoperative FABP1 levels were risk factors for hyperuricemia at baseline. UA and FABP1 levels decreased at 3, 6, and 12 months postoperatively. FABP1 showed a more significant decrease in the HUA group than in the NUA group at 12 months (27.06 ± 10.98 ng/mL vs. 9.54 ± 6.52 ng/mL, P=0.003). Additionally, the change in FABP1 levels positively correlated with changes in UA levels in the HUA group 12 months postoperatively (r=0.512, P=0.011).

CONCLUSIONS

FABP1 was positively associated with UA and may be a risk factor for hyperuricemia in obesity. FABP1 levels were higher but decreased more after LSG in obese patients with hyperuricemia than in those without hyperuricemia.

Assessment of causal associations between uric acid and 25-hydroxyvitamin D levels

BACKGROUND

Previous observational studies have revealed the association between serum uric acid and 25-hydroxyvitamin D. However, the causality and the direction of the associations remain unknown. Thus, we performed a two-sample bidirectional Mendelian Randomization (MR) analysis to investigate the causal association between uric acid and 25-hydroxyvitamin D and to determine the direction of the association.

METHOD

Based on the summary-level GWAS data from large genome-wide association studies, several steps were taken in our analysis to select eligible single-nucleotide polymorphisms (SNPs), which were strongly related to exposure as the instrumental variables. We used different analytical methods, such as inverse-variance weighting (IVW) method, weighted median, MR-Egger regression, and weighted mode method, to make our result more robust and reliable. The IVW method was used as the primary analysis. The Cochran's Q test, MR-Egger intercept test, MR-PRESSO method, and "leave-one-out" sensitivity analysis was performed to evaluate the heterogeneities, horizontal pleiotropy, and robustness of the results. MR analyses were also conducted using genetic risk scores (GRS) as instrumental variables in both directions by using the same summary-level GWAS data.

RESULTS

Our two-sample MR analysis suggested a causal association of genetically predicted uric acid on 25-hydroxyvitamin D [IVW method: β(SE), -0.0352(0.0149); p = 0.0178], which suggested that a per mg/dl increase in uric acid was associated with a decrease of 0.74 nmol/L of 25-hydroxyvitamin D, and the above results remained stable in the sensitivity analysis. By contrast, four MR methods suggested no causal relationship of 25-hydroxyvitamin D on serum uric acid [IVW β(SE), 0.0139 (0.0635); p = 0.826; MR-Egger β(SE), 0.0671 (0.108); p = 0.537; weighted median β(SE), 0.0933 (0.0495); p = 0.0598; weighted mode β(SE), 0.0562 (0.0463); p = 0.228, respectively]. After excluding the SNPs, which were associated with confounding factors and outlier SNPs, the IVW method suggested that there was still no causal association of 25-hydroxyvitamin D on serum uric acid. The GRS approach showed similar results.

CONCLUSIONS

Serum uric acid may causally affect the 25-hydroxyvitamin D levels, whereas the causal role of 25-hydroxyvitamin D on uric acid was not supported in our MR analysis. Our findings suggest that increased levels of uric acid should prompt investigation for vitamin D deficiency.

Relationship Between Serum Uric Acid-to-Creatinine Ratio and the Risk of Metabolic-Associated Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus

PURPOSE

To investigate the association between serum uric acid-to-creatinine ratio (SUA/Cr) and the risk of developing metabolic-associated fatty liver disease (MAFLD) in patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

Overall, 1434 patients with T2DM who were admitted to Hebei General Hospital from January 2019 to December 2019 were selected as the study subjects. According to abdominal ultrasound findings, patients were divided into two groups: MAFLD group and non-MAFLD group. A total of 734 patients were diagnosed with MAFLD. Participants were divided into three study groups according to the SUA/Cr ratio. Chi-square test and one-way analysis of variance were used to perform a comparison between groups. The relationship between SUA/Cr ratio and MAFLD risk was analyzed using correlation analysis and regression analysis. Furthermore, subgroup analyses were performed to verify the robustness of the results.

RESULTS

The detection rate of MAFLD in patients with T2DM was 51.2%, and the detection rate of progressive liver fibrosis in T2DM patients with MAFLD was 36.6%. A significantly higher SUA/Cr ratio was seen in the MAFLD group than in the non-MAFLD group. After adjusting for confounding factors, multivariate logistic regression analysis revealed that the SUA/Cr ratio was an independent risk factor for MAFLD development. Stronger correlations were found in participants with a body mass index ranging between 23 and 28 kg/m2, HbA1C >7%, or female sex.

CONCLUSION

An elevated SUA/Cr index is independently correlated with an increased risk of MAFLD in Chinese adults with T2DM.

Burden of Metabolic Syndrome Among a Low-Income Population in China: A Population-Based Cross-Sectional Study

INTRODUCTION

Metabolic syndrome (MetS) is a chronic and complex disease associated with all-cause mortality, cardiovascular disease, and type 2 diabetes. The present study aimed to evaluate the prevalence of MetS and its risk factors among middle-aged and older adults in low-income, low-education rural areas with a high incidence of stroke.

METHODS

This cross-sectional study of the general population was performed from April 2019 to June 2019 in rural areas of Tianjin, China. All eligible residents aged ≥ 45 years and without active malignant tumors, hepatic failure, and severe renal disease underwent routine medical examinations, which included a questionnaire, physical examination, and routine blood and biochemical tests. The modified International Diabetes Federation criteria for the Asian population was used to identify patients with MetS.

RESULTS

A total of 3175 individuals (44.8% men, 55.2% women) were included in the final analysis. The prevalence of MetS was 52.8%, with higher prevalence in women than in men (62.4%and 40.9%, respectively). Of the five MetS components, high blood pressure and abdominal obesity were the two most prevalent in both women and men, accounting for 89.3% and 62.0%, respectively, followed by elevated fasting plasma glucose, low high-density lipoprotein cholesterol, and elevated triglycerides. Multivariate logistic regression analysis revealed the following traits to be risk factors for MetS: female sex, self-reported smoking, self-reported snoring, high body mass index, high waist-to-hip ratio, and high serum urate level.

CONCLUSION

The prevalence of MetS was quite high in rural areas with a low-income, low-education population. Implementing preventive and therapeutic interventions based on these risk factors is essential to prevent metabolic abnormalities.

Adipose Tissue Insulin Resistance Is Positively Associated With Serum Uric Acid Levels and Hyperuricemia in Northern Chinese Adults

OBJECTIVE

Adipose tissue plays a crucial role in serum uric acid (UA) metabolism, but the relative contribution of adipose tissue insulin resistance (IR) to serum UA levels and hyperuricemia have not explicitly been illustrated. Herein, we aimed to investigate the association between the adipose tissue insulin resistance index (Adipo-IR) and hyperuricemia in this cross-sectional study. The homeostasis model assessment of insulin resistance (HOMA-IR) index, another widely applied marker to determine systemic IR, was also explored.

METHODS

A total of 5821 adults were included in this study. The relationship between Adipo-IR or HOMA-IR and serum UA levels was assessed by multivariate linear regression. Binary logistic regression analyses were applied to determine the sex-specific association of the Adipo-IR tertiles and HOMA-IR tertiles with hyperuricemia. Participants were then divided into normal BMI (18.5 ≤ BMI < 24) and elevated BMI (BMI ≥ 24) groups for further analysis.

RESULTS

Both Adipo-IR and HOMA-IR were positively correlated with serum UA (P < 0.001). Compared with the lowest tertile, the risks of hyperuricemia increased across Adipo-IR tertiles (middle tertile: OR 1.52, 95%CI 1.24-1.88; highest tertile: OR 2.10, 95%CI 1.67-2.63) in men after full adjustment (P for trend < 0.001). In women, only the highest tertile (OR 2.09, 95%CI 1.52-2.87) was significantly associated with hyperuricemia. Those associations remained significant in participants with normal BMI status. As for HOMA-IR, only the highest tertile showed positive relationships with hyperuricemia in both genders after full adjustment (P for trend < 0.001). The association between HOMA-IR and hyperuricemia disappeared in men with normal BMI status.

CONCLUSIONS

Adipo-IR was strongly associated with serum UA and hyperuricemia regardless of BMI classification. In men with normal BMI, Adipo-IR, rather than HOMA-IR, was closely associated with hyperuricemia. Altogether, our finding highlights a critical role of adipose tissue IR on serum UA metabolism and hyperuricemia.

Relationship Between Four Non-Insulin-Based Indexes of Insulin Resistance and Serum Uric Acid in Patients with Type 2 Diabetes: A Cross-Sectional Study

AIM

The aim of this study was to investigate the association between serum uric acid (SUA) levels and four insulin resistance surrogates in patients with type 2 diabetes (T2DM). The four non-insulin-based indexes of insulin resistance (IR) include the glucose and triglycerides index (TyG), TyG index with body mass index (TyG-BMI), ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL-c) and metabolic score for insulin resistance (METS-IR).

METHODS

A total of 687 patients with T2DM were enrolled in the current study. Patients were stratified into three groups according to their levels of SUA. Spearman correlation was used to analyze the correlation between SUA and clinical variables. Multiple linear regression analysis was used to assess the association between SUA and the four insulin resistance surrogates. Receiver operating characteristic (ROC) analyses and the area under the ROC curve (AUC) were then used to assess the ability of TyG, TyG-BMI, TG/HDL-c, and METS-IR to discriminate hyperuricemia (HUA) in T2DM.

RESULTS

SUA in T2DM was significantly positively correlated with TyG (r 0.406 P < 0.01), TyG-BMI (r 0.272 P < 0.01), TG/HDL-c (r 0.493 P < 0.01), and METS-IR (r 0.238 P < 0.01). Furthermore, higher values of the four insulin resistance surrogates were independently correlated with higher SUA levels in T2DM patients (P < 0.01 for all) after adjusting for confounding factors. TyG, TyG-BMI, TG/HDL-c, and METS-IR all had a significant discriminative ability for HUA in patients with T2DM. The AUC values were 0.693 (95% CI 0.645-0.741), 0.649 (95% CI 0.599-0.699), 0.768 (95% CI 0.726-0.811), and 0.660 (95% CI 0.609-0.710), respectively.

CONCLUSION

The present study suggests that TyG, TyG-BMI, TG/HDL-c and METS-IR had a significant correlation with SUA in T2DM. TG/HDL-c was the best marker among the four insulin resistance surrogates for the identification of HUA in T2DM.

The Association with Subclinical Thyroid Dysfunction and Uric Acid

The relationship between subclinical thyroid dysfunction and uric acid was not well established. This study aimed to determine if subclinical thyroid dysfunction is associated with hyperuricemia risk and to evaluate the levels of uric acid in patients with different forms of subclinical thyroid dysfunction. A systematic search was conducted in 4 databases to obtain relevant studies on subclinical thyroid dysfunction (subclinical hyperthyroidism and subclinical hypothyroidism) and uric acid. The standardized mean difference (SMD) or odds ratio (OR) and 95% confidence interval (95% CI) were used for evaluation, and the sensitivity analysis was conducted. Publication bias was estimated by funnel plot, Egger's test, and Begg's test. A total of 73 studies were included in this meta-analysis. The results demonstrated that serum levels of uric acid in patients with subclinical hypothyroidism were significantly higher than those of controls and patients with subclinical hyperthyroidism. Patients with subclinical thyroid dysfunction had a higher prevalence of hyperuricemia compared with normal clinical thyroid function. Subclinical thyroid dysfunction was associated with the prevalence of hyperuricemia. Different types of subclinical thyroid dysfunction had varied effects on serum levels of uric acid.

Metabolic Syndrome-Related Hyperuricemia is Associated with a Poorer Prognosis in Patients with Colorectal Cancer: A Multicenter Retrospective Study

PURPOSE

Hyperuricemia and metabolic syndrome (MetS) have been shown to correlate with prognosis in patients with malignant tumors. The present study evaluated the relationship between preoperative hyperuricemia and MetS in colorectal cancer (CRC) patients and analyzed the effect of this combination on prognosis within 5 years.

PATIENTS AND METHODS

The study enrolled patients who had undergone radical CRC resection at three independent medical centers from January 2014 to December 2016. Patients were preoperatively categorized into four groups, those with hyperuricemia alone (H), those with MetS alone (MS), those with MetS-related hyperuricemia (MSH), and those with neither condition (control [C] group). The disease-free survival (DFS) and overall survival (OS) rates of these four groups were compared.

RESULTS

The study population consisted of 1271 patients, with 114, 201, 101, and 855 patients categorized into the H, MS, MSH and C groups, respectively. Preoperative MetS was found to be significantly associated with hyperuricemia (P < 0.001). Multivariate Cox regression analysis showed that MetS-related hyperuricemia (hazard ratio [HR] = 2.728; P < 0.001) and MetS alone (HR = 1.631; P < 0.001) were independent predictors of death, whereas simple hyperuricemia was not (P > 0.1). Relative to the C group, the MSH group had the highest rate of tumor recurrence or metastasis (HR = 5.103, P < 0.001), followed by the MS (HR = 2.231, P < 0.001) group. In contrast, prognosis did not differ significantly in the H and C groups (P > 0.1). MetS was significantly associated with poor prognosis, with MetS-related hyperuricemia resulting in a significantly poorer prognosis. In contrast, hyperuricemia alone had no effect on the long-term prognosis of CRC patients.

CONCLUSION

This study highlights the prognostic importance of MetS-related hyperuricemia on the survival of patients with CRC.

Hyperuricemia prevalence and its association with metabolic disorders: a multicenter retrospective real-world study in China

Background

The prevalence of hyperuricemia (HUA) and gout continues to increase in China. Research suggests that HUA may be related to many diseases other than gout. However, further population research is required to investigate the association between HUA and metabolic syndromes. This study sought to investigate the prevalence of HUA in an average population in China, and the association between serum uric acid (UA) levels and related metabolic disorders.

Methods

This multicenter retrospective real-world study examined the hospital information system data of 4 tertiary hospitals in 3 provinces in China. The data of patients aged between 18 and 80 years, who had attended at least 1 medical appointment at which their UA level was recorded, were analyzed to evaluate associations between UA levels and metabolic disorders.

Results

Among the 374,506 enrolled subjects (49.7% male; mean age 51.5 years old), the overall prevalence of HUA and gout were 14.8% and 0.5%, respectively. The prevalence was higher among males than females (17.6% vs. 12.0%, 0.8% vs. 0.1%; both P<0.001). Groups exhibiting higher UA levels had increased adjusted odds ratios for dyslipidemia and chronic kidney disease (CKD) in both sexes. Changes in UA levels from the baseline were negatively correlated with changes in the estimated glomerular filtration rate and hemoglobin A1c among both sexes (all P<0.001), and were positively correlated with changes in total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) (all P<0.05) among males, and changes in TC, TG, LDL-C and glucose (all P<0.001) among females.

Conclusions

HUA is associated with dyslipidemia and CKD both cross-sectionally and longitudinally. Similar phenomena were observed in both sexes.

Age and Gender-Specific Reference Intervals for Uric Acid Level in Children Aged 5-14 Years in Southeast Zhejiang Province of China: Hyperuricemia in Children May Need Redefinition

Context: Hyperuricemia is defined when the plasma uric acid concentration is above 416 μmol/L (7 mg/dl) in male adults, or 357 μmol/L (6 mg/dl) in female adults. However, there are no explicit criteria yet for children. Objective: It is necessary to set up reference intervals for the uric acid level in different age groups among children. Materials and Methods: A total of 5,439 individuals (3,258 males, 2,181 females) were included in the final statistical analysis. Reference values of all age groups were determined by statistical descriptions. Multiple linear regression analysis was applied to determine the relationship between uric acid level, BMI, and age. Results: The level of uric acid increased with age. Gender differences in uric acid level occurred after the onset of puberty. Additionally, linear regression revealed a positive correlation between the uric acid level and BMI. Discussion and Conclusion: The reference range of the uric acid level in children is inconsistent with the previous viewpoint. Body mass index plays an important role in uric acid metabolism.

Interaction of Alcohol Consumption and ABCG2 rs2231142 Variant Contributes to Hyperuricemia in a Taiwanese Population

Background: ABCG2 rs2231142 is an important genetic factor that contributes to the development of gout and hyperuricemia (HUA). Epidemiologic studies have demonstrated that lifestyle risk factors of HUA (e.g., alcohol consumption) and genetic predisposition (e.g., ABCG2 gene) together, contribute to enhanced serum uric acid levels. However, the interaction between ABCG2 rs2231142, alcohol consumption, and HUA in the Taiwanese population is still unclear. Therefore, this study investigated whether the risk of HUA is associated with ABCG2 rs2231142 variants and how this is affected by alcohol consumption. Method: study subjects were selected from the participants of the Taiwan Biobank database. Overall, 114,540 participants aged 30 to 70 years were enrolled in this study. The interaction between ABCG2 rs2231142, alcohol consumption, and serum uric acid (sUA) levels was analyzed by multiple logistic regression models. Results: the prevalence of HUA was 32.7% and 4.4 % in the male and female populations, respectively. In the whole study population, the minor T allele of ABCG2 rs2231142 was significantly associated with HUA risk, and the occurrence of HUA was high in TT genotype and TG genotype. The risk of HUA was significantly increased by the combined association of ABCG2 rs2231142 and alcohol consumption for TG/TT genotype compared to the GG genotype (wild-type genotype), especially among women. Conclusion: the ABCG2 rs2231142 is a crucial genetic locus for sUA levels in the Taiwanese population and our findings revealed that alcohol consumption combined with the ABCG2 rs2231142 risk allele contributes to increased HUA risk.

Association between gut microbiota and elevated serum urate in two independent cohorts

OBJECTIVES

Hyperuricemia is a precursor to gout and is often present in other metabolic diseases that are promoted by microbiome dysbiosis; however, no study has examined the association of gut microbiota with hyperuricemia and serum urate in humans.

METHODS

Study participants were derived from a community-based observational study, the Xiangya Osteoarthritis Study (discovery cohort). Hyperuricemia was defined as the presence of serum urate level >357 μmol/L for women and >416 μmol/L for men. Gut microbiota was analyzed using 16S rRNA sequencing from stool samples. We examined the relation of microbiota dysbiosis (i.e., richness, diversity, composition, and relative abundance of microbiota taxa) and predicted functional pathways to prevalent hyperuricemia and serum urate levels. We verified the associations in an independent observational study, the Step Study (validation cohort).

RESULTS

The discovery cohort consisted of 1,392 rural participants (mean age: 61.3 years; women: 57.4%; hyperuricemia: 17.2%). Participants with hyperuricemia had decreased richness and diversity, altered composition of microbiota, and lower relative abundances of genus Coprococcus compared with those with normouricemia. Predicted Kyoto Encyclopedia of Genes and Genomes metabolism pathways belonged to amino acid and nucleotide metabolisms were significantly altered in individuals with hyperuricemia compared with those with normouricemia. Gut microbiota richness, diversity and low relative abundances of genus Coprococcus were also associated with high levels of serum urate. These findings were replicated in the validation cohort with 480 participants.

CONCLUSIONS

Gut microbiota dysbiosis was associated with elevated serum urate levels. Our study raises the possibility that microbiota dysbiosis may modulate serum urate levels.

The association between vitamin D3 and diabetes in both hyperuricemia and non-hyperuricemia populations

BACKGROUND

Previous studies have shown that hyperuricemia is involved in diabetes, obesity, hypertension, chronic kidney disease, and other diseases. At the same time, studies have shown that vitamin D3 levels in the body are linked to the onset of diabetes. However, there is currently no sufficient evidence to prove whether this connection is affected by the uric acid level. Therefore, we attempted to investigate the association between vitamin D3 content and the occurrence of diabetes in populations with different uric acid levels though the data of NHANES database from 2009 to 2018.

METHOD

Using the NHANES database, we performed a cross-sectional analysis. The participants were chosen based on stringent inclusion and exclusion requirements. This study finally included a total number of 16,735 individuals. Multivariate logistic regression analysis was used to investigate the association between vitamin D3 and diabetes mellitus in hyperuricemia and non-hyperuricemia patients after complete adjustment, and multivariate linear regression analysis was used to illustrate the association between vitamin D3 and uric acid.

RESULT

The results showed that the association between vitamin D3 and diabetes was weakened in hyperuricemia patients (OR 0.95 (0.92,0.98)). An independent association was discovered between vitamin D3 and uric acid (β -0.12 (-0.16, -0.07)) in all groups of population.

CONCLUSIONS

This study shows that vitamin D3 content is associated with the incidence of diabetes in people with high level of uric acid. This study offers a fresh perspective on the elements that influence the etiology of diabetes in hyperuricemia patients.

Dependence of Heart Rate Variability Indices on the Mean Heart Rate in Women with Well-Controlled Type 2 Diabetes

Heart rate variability (HRV) is a method used to evaluate the presence of cardiac autonomic neuropathy (CAN) because it is usually attributed to oscillations in cardiac autonomic nerve activity. Recent studies in other pathologies suggest that HRV indices are strongly related to mean heart rate, and this does not depend on autonomic activity only. This study aimed to evaluate the correlation between the mean heart rate and the HRV indices in women patients with well-controlled T2DM and a control group. HRV was evaluated in 19 T2DM women and 44 healthy women during basal supine position and two maneuvers: active standing and rhythmic breathing. Time-domain (SDNN, RMSSD, pNN20) and frequency-domain (LF, HF, LF/HF) indices were obtained. Our results show that meanNN, age, and the maneuvers are the main predictors of most HRV indices, while the diabetic condition was a predictor only for pNN20. Given the known reduced HRV in patients with T2DM, it is clinically important that much of the HRV indices are dependent on heart rate irrespective of the presence of T2DM. Moreover, the multiple regression analyses evidenced the multifactorial etiology of HRV.

Function of Uric Acid Transporters and Their Inhibitors in Hyperuricaemia

Disorders of uric acid metabolism may be associated with pathological processes in many diseases, including diabetes mellitus, cardiovascular disease, and kidney disease. These diseases can further promote uric acid accumulation in the body, leading to a vicious cycle. Preliminary studies have proven many mechanisms such as oxidative stress, lipid metabolism disorders, and rennin angiotensin axis involving in the progression of hyperuricaemia-related diseases. However, there is still lack of effective clinical treatment for hyperuricaemia. According to previous research results, NPT1, NPT4, OAT1, OAT2, OAT3, OAT4, URAT1, GLUT9, ABCG2, PDZK1, these urate transports are closely related to serum uric acid level. Targeting at urate transporters and urate-lowering drugs can enhance our understanding of hyperuricaemia and hyperuricaemia-related diseases. This review may put forward essential references or cross references to be contributed to further elucidate traditional and novel urate-lowering drugs benefits as well as provides theoretical support for the scientific research on hyperuricemia and related diseases.

High-Throughput Untargeted Serum Metabolomics Analysis of Hyperuricemia Patients by UPLC-Q-TOF/MS

Hyperuricemia (HUA) as a metabolic disease is closely associated with metabolic disorders. The etiology and pathogenesis of HUA are not fully understood, so there is no radical cure so far. Metabolomics, a specialized study of endogenous small molecule substances, has become a powerful tool for metabolic pathway analysis of selected differential metabolites, which is helpful for initially revealing possible development mechanisms of various human diseases. Twenty HUA patients and 20 healthy individuals participated in the experiment, and ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was employed to investigate serum samples to find differential metabolites. The statistical techniques used were principal component analysis and orthogonal partial least-squares discriminant analysis. The differences in metabolomics results of samples after pretreatment with different solvents were compared, 38, 20, 26, 28, 33, 50, and 40 potential differential metabolites were found, respectively, in HUA patient samples, and each group involved different metabolic pathways. Repetitive metabolites were removed, 138 differential metabolites in HUA serum were integrated for analysis, and the human body was affected by 7 metabolic pathways of glycerophospholipid metabolism, sphingolipid metabolism, arachidonic acid metabolism, linoleic acid metabolism, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and α-linolenic acid metabolism. In this work, the metabolomics approach based on UPLC-Q-TOF/MS was employed to investigate serum metabolic changes in HUA patients, 138 potential differential metabolites related to HUA were identified, which provided associations of lipids, amino acids, fatty acids, organic acids, and nucleosides profiles of HUA individuals. Metabolic pathways involved in glycerophospholipid metabolism, sphingolipid metabolism, arachidonic acid metabolism, linoleic acid metabolism, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and a-linolenic acid metabolism shed light on the understanding of the etiology and pathogenesis process of HUA.

An update of genetics, co-morbidities and management of hyperuricaemia

Hyperuricaemia (HU) caused by disorders of purine metabolism is a metabolic disease. A number of epidemiological reports have confirmed that HU is correlated with multiple disorders, such as chronic kidney diseases, cardiovascular disease and gout. Recent studies showed that the expression and functional changes of uric acid transporters, including URAT1, GLUT9 and ABCG2, were associated with HU. Moreover, a large number of genome-wide association studies have shown that these transporters' dysfunction leads to HU. In this review, we describe the recent progress of aetiology and related transporters of HU, and we also summarise the common co-morbidities possible mechanisms, as well as the potential pharmacological and non-pharmacological treatment methods for HU, aiming to provide new ideas for the treatment of HU.

Sugar-sweetened soft drinks consumption and risk of hyperuricemia: Results of the ELSA-Brasil study

BACKGROUND AND AIMS

The prospective association between sugar-sweetened beverages consumption and hyperuricemia is controversial. The aim was to investigate the association of the consumption of sugar-sweetened soft drinks and unsweetened fruit juices with the incidence of hyperuricemia and the levels of serum uric acid in the participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS AND RESULTS

Longitudinal analysis in ELSA-Brasil participants (baseline 2008-2010 and follow-up 2012-2014). The sample consisted of 10,072 civil servants (35-74 years, both sexes). The consumption of beverages estimated by a food frequency questionnaire (baseline) was divided into five categories: nonconsumption and quartiles (≥0.1 mL/day). Hyperuricemia was defined as uric acid ≥7.0 mg/dL (men) and ≥5.7 mg/dL (women). Poisson regression with robust variance and multiple linear regression were tested. The average consumption of soft drinks was 84 ± 191 mL/day in men and 42 ± 128 mL/day in women. After 4 years of follow-up, the higher consumption of soft drinks (men: 401 ± 303 mL/day; women: 390 ± 290 mL/day) increased the relative risk of hyperuricemia by 30% (men) and 40% (women), and was associated with increased mean uric acid (men: β = 0.14 mg/dL; 95% CI 0.41-0.24; women: β = 0.11 mg/dL; 95% CI 0.00-0.21). The consumption of unsweetened juice was not associated with hyperuricemia.

CONCLUSION

High consumption of sugar-sweetened soft drinks is associated with an increased relative risk of hyperuricemia and elevated serum uric acid levels in Brazilian adults.

Vitamin D3 potentiates the nephroprotective effects of metformin in a rat model of metabolic syndrome: role of AMPK/SIRT1 activation and DPP-4 inhibition

The current study aimed to investigate the molecular mechanisms of metformin and vitamin D3-induced nephroprotection in a metabolic syndrome (MetS) rat model, evaluating the capacity of vitamin D3 to potentiate metformin action. MetS was induced by 10% fructose in drinking water and 3% salt in the diet. After 6 weeks, serum lipid profile and uric acid were measured, an oral glucose tolerance test (OGTT) was performed, and kidney function was investigated. In conjunction with the same concentrations of fructose and salt feeding, MetS rats with significant weight gain, dyslipidemia, hyperuricemia, and dysglycemia were treated orally with metformin (200 mg/kg), vitamin D3 (10 µg/kg), or both daily for 6 weeks. At the end of the study period, anthropometrical parameters were recorded, OGTT was reperformed, urine and blood samples were collected, and tissue samples were harvested at sacrifice. MetS rats showed dramatically declined renal function, enhanced intrarenal oxidative stress and inflammation, and extravagant renal histopathological damage with interstitial fibrosis. Metformin and vitamin D3 significantly reversed all the aforementioned deleterious effects in MetS rats. The study has verified the nephroprotective effects of metformin and vitamin D3 in MetS, accentuating the critical role of AMP-activated protein kinase/sirtuin-1 activation and dipeptidyl peptidase-4 inhibition. Given the synergistic effects of the combination, vitamin D3 is worth being investigated as an additional therapeutic agent for preventing MetS-induced nephropathy.

Taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism

Objective

To evaluate the taxonomic composition of the gut microbiome in gout patients with and without tophi formation, and predict bacterial functions that might have an impact on urate metabolism.

Methods

Hypervariable V3–V4 regions of the bacterial 16S rRNA gene from fecal samples of gout patients with and without tophi (n = 33 and n = 25, respectively) were sequenced and compared to fecal samples from 53 healthy controls. We explored predictive functional profiles using bioinformatics in order to identify differences in taxonomy and metabolic pathways.

Results

We identified a microbiome characterized by the lowest richness and a higher abundance of Phascolarctobacterium, Bacteroides, Akkermansia, and Ruminococcus_gnavus_group genera in patients with gout without tophi when compared to controls. The Proteobacteria phylum and the Escherichia-Shigella genus were more abundant in patients with tophaceous gout than in controls. Fold change analysis detected nine genera enriched in healthy controls compared to gout groups (Bifidobacterium, Butyricicoccus, Oscillobacter, Ruminococcaceae_UCG_010, Lachnospiraceae_ND2007_group, Haemophilus, Ruminococcus_1, Clostridium_sensu_stricto_1, and Ruminococcaceae_UGC_013). We found that the core microbiota of both gout groups shared Bacteroides caccae, Bacteroides stercoris ATCC 43183, and Bacteroides coprocola DSM 17136. These bacteria might perform functions linked to one-carbon metabolism, nucleotide binding, amino acid biosynthesis, and purine biosynthesis. Finally, we observed differences in key bacterial enzymes involved in urate synthesis, degradation, and elimination.

Conclusion

Our findings revealed that taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00311-5.

Screening and Evaluation of Purine-Nucleoside-Degrading Lactic Acid Bacteria Isolated from Winemaking Byproducts In Vitro and Their Uric Acid-Lowering Effects In Vivo

In Taiwan, adult hyperuricemia affects as many as 1 in 4 males and 1 in 6 females, who are predominantly young adults aged 19–45. In this study, lactic acid bacteria (LAB) with acid tolerance, bile salt tolerance and high affinity to intestinal cells were extracted from the side products of alcohol fermentation (distillers’ grains). These bacteria were evaluated for their ability to lower uric acid levels. Qualitative identification and quantitative analysis were performed using high-performance liquid chromatography (HPLC) on the purine-degrading enzymes to select purine-decomposing LAB for animal testing. When the final concentration of purine compounds reached 0.1% and 1%, seven strains of LAB showed potential in degrading purine compounds. HPLC was used to analyze their purine-degrading abilities, and the three best performing LAB strains, (107) 8–16, (107) tau 1–3, and (107) 6–10 were screened for further animal testing with Wistar rats. By the third week, the results showed that strain (107) 6–10 could prevent formation and reduce the levels of blood urea nitrogen (BUN) in yeast extract/potassium oxonate-induced hyperuricemia. The multi-strain lactic acid bacteria (MLAB) performed best for uric acid reduction in the serum and down regulated BUN. Yeast extract/potassium oxonate-induced hyperuricemia had no impact on serum creatinine, while LAB did not affect the creatinine concentration. In summary, MLAB not only protects kidney function but is also effective in regulating uric acid concentration in the body. Hence, MLAB can be used as a functional food supplement that prevents or aids the treatment of hyperuricemia in a rodent model.

The Effect of Chalcones on the Main Sources of Reactive Species Production: Possible Therapeutic Implications in Diabetes Mellitus

Diabetes mellitus (DM) is characterized by hyperglycaemia, resulting from defects in insulin secretion, insulin action or both. There are several factors such as hyperlipidemia and oxidative stress (OS), namely the production of reactive oxygen/nitrogen species (ROS/RNS), that actively contribute to the development and worsening of DM. Chalcones, also termed as benzalacetophenone or benzylidene acetophenone, present a 1,3-diaryl-2-propen-1-one scaffold that has been shown to be highly promising in the development of new antioxidant compounds. Considering the potential interest of antioxidant therapy, the present review scrutinizes the role of the main sources of ROS/RNS production during DM. The modulatory effect of chalcones against nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, xanthine oxidase, mitochondrial respiratory chain and nitric oxide synthase, is also thoroughly discussed, establishing, whenever possible, a structure-activity relationship (SAR). From the SAR analysis, it can be stated that the presence of catechol groups, hydroxyl and methoxyl substituents in the chalcones scaffold improves their modulatory activity against the main sources of ROS/RNS production in DM.

Correlation between epicardial fat thickness with intima-media thickness and ankle-brachial index in patients with metabolic syndrome

Background An increase in epicardial fat thickness (EFT) has been associated with increased cardiovascular risk and the development of atherosclerosis. Transthoracic echo-cardiography provides a reliable measurement of EFT. We evaluated the relationship of EFT with carotid intima-media thickness (CIMT) and ankle-brachial index (ABI), in patients with metabolic syndrome. Methods We assessed 80 patients with metabolic syndrome who underwent echocardiography; EFT was measured by two cardiologists. The CIMT (B-mode colour imaging of extracranial carotid arteries using high-resolution ultrasound) was also measured by a certified ultrasonographer, and ABI was measured by the main researcher. Results We did not find any correlation between ABI with EFT (r=0.0103, p=0.93) or with CIMT (r=-0.1625, p=0.15). However, we found a significant correlation between EFT and CIMT (r=0.2718, r2=0.074, p=0.015). When we evaluated the risk for a CIMT >0.9 mm in patients with an EFT >3 mm, we found a statistically significant association (p=0.039). Interestingly, only 1 patient with an EFT <3 mm had a CIMT >0.9 mm. Conclusion We found that the EFT correlates with CIMT in patients with metabolic syndrome, which explains, at least in part, the higher risk of atherosclerosis in them. Measurement of EFT should be part of the cardiovascular risk evaluation in patients with metabolic syndrome.

The Serum Uric Acid Level Is Related to the More Severe Renal Histopathology of Female IgA Nephropathy Patients

Hyperuricemia is a significant risk factor for cardiovascular morbidity and chronic kidney disease progression. IgA nephropathy (IgAN) is a well-known primary glomerular nephropathy. Hyperuricemia is associated with a poor prognosis in IgAN patients. We evaluated the association of hyperuricemia with the histopathological severity of IgAN in male and female patients; 658 patients diagnosed with IgAN via kidney biopsy were initially included. Baseline patient data were collected by eight university hospitals affiliated with the College of Medicine of the Catholic University of Korea. Pathological features were independently evaluated by eight expert pathologists working in the hospitals, and the consensus was reached. Of the initial 658 patients, 517 were finally included (253 males and 264 females). Hyperuricemia was defined as a serum uric acid (UA) level >7.0 mg/dL for males and >5.6 mg/dL for females; 108 (42.7%) males and 95 (35.9%) females exhibited hyperuricemia. Compared to the patients with normal UA levels, the global glomerulosclerosis, segmental sclerosis, mesangial matrix expansion (MME), endocapillary proliferation (ECP), interstitial fibrosis (IF), and tubular atrophy (TA) scores were higher in hyperuricemic males and females. In multivariable linear regression, the serum UA level correlated significantly with the MME, ECP, IF, and TA scores of female IgAN patients only.