Meta-analysis of 28,141 individuals identifies common variants within five new loci that influence uric acid concentrations

Genetic risk, lifestyle adherence, and risk of developing hyperuricaemia in a Japanese population

OBJECTIVE

The objective of this study was to investigate the inter-relationships among genetic risk, adherence to a healthy lifestyle, and susceptibility to hyperuricaemia.

METHODS

This prospective cohort study was conducted with 7241 hyperuricaemia-free individuals aged ≥20 years from the Tohoku Medical Megabank Community-based cohort study. A comprehensive lifestyle score included assessment of BMI, smoking, drinking, and physical activity, and a polygenic risk score (PRS) was constructed based on uric acid loci from a previous genome-wide association study meta-analysis. A multiple logistic regression model was used to estimate the association between genetic risk, adherence to a healthy lifestyle, and hyperuricaemia incidence and to calculate the area under the receiver operating characteristic curve (AUROC). Hyperuricaemia was defined as a uric acid level of ≥7.0 mg/dL or a self-reported history of hyperuricaemia.

RESULTS

Of the 7241 adults [80.7% females; mean (±s.d.) age: 57.7 (12.6) years], 217 (3.0%) developed hyperuricaemia during 3.5 years of follow-up period. Genetic risk was correlated with hyperuricaemia development (P for interaction = 0.287), and lifestyle risks were independently associated. Participants with a high genetic risk and poor lifestyle had the highest risk (odds ratio: 5.34; 95% CI: 2.61-12.10). Although not statistically significant, adding the PRS in the model with lifestyle information improved predictive ability (AUROC = 0.771, 95% CI: 0.736-0.806 for lifestyle; AUROC = 0.785, 95% CI: 0.751-0.819 for lifestyle and PRS; P= 0.07).

CONCLUSION

A healthy lifestyle to prevent hyperuricaemia, irrespective of genetic risk, may mitigate the genetic risk. Genetic risk may complement lifestyle factors in identifying individuals at a heightened hyperuricaemia risk.

Integration of metabolomics and genomics implicates a causality between 1398 blood metabolites and gout

INTRODUCTION

Metabolic disorders represent a hallmark feature of gout. However, evidence on the causality of blood metabolites and gout remains lacking. We performed a Mendelian randomization (MR) analysis to systematically evaluate the causality from genetically proxied 1398 blood metabolites to gout.

METHOD

Genome-wide association study (GWAS) data for 1398 blood metabolites were extracted from 8299 European subjects. The discovery stage was performed using gout data from FinnGen consortium R9 to initially explore causal associations between metabolites and gout. The significant associations identified in the discovery stage were validated in the replication stage employing gout GWAS data from the IEU database. Random-effect inverse variance weighted was chosen as the main method for causality analysis, with MR-Egger, weighted median, robust adjusted profile score, and maximum likelihood as complementary analysis methods. Then, a series of sensitivity analyses were performed.

RESULTS

Results showed that there was a significant causal relationship between eight metabolites and gout, including 21-hydroxypregnenolone disulfate levels, carnitine levels, ethyl beta-glucopyranoside levels, gamma-glutamylglycine levels, glycine levels, glycine-to-alanine ratio, glycolithocholate sulfate levels, and propionylglycine levels. Colocalization analysis evidence strongly supported a causal relationship between 21-hydroxypregnenolone disulfate levels and carnitine levels and gout. In addition, four metabolic pathways were involved in the biological process of gout (carnitine synthesis, beta oxidation of very long-chain fatty acids, alanine metabolism, glutathione metabolism).

CONCLUSIONS

The current study provides evidentiary support for the causal relationship between eight blood metabolites and gout and identifies four significant metabolic pathways. These findings hold the potential to inform future research, clinical interventions, and therapeutic strategies for gout.

Association between genotypes of ABCB1 and ABCG2 and the risk of atrial fibrillation

AIMS

Atrial fibrillation (AF) is a prevalent clinical condition worldwide, with a high global incidence that significantly impacts disease burden and mortality rates. Single nucleotide polymorphisms in ABCB1 and ABCG2 are common, but the clinical outcomes are poorly understood. This study examines the association between the genetic variations of ABCB1 and ABCG2 and the risk of AF in a Taiwanese population.

METHODS AND RESULTS

This case-control study recruited 216 AF patients from two hospitals in Taiwan between 2021 and 2023. Control groups were matched by age (± one year), gender, and AF-related variables from the Taiwan Biobank. Logistic regression analyzed the association between three genetic variants and AF risk. A significant association was noted between ABCG2 rs2231142 and AF risk. Those with ABCG2 rs2231142 G/T and T/T genotypes had a 1.91-fold (95 % CI = 1.04-3.53) increased risk of AF compared to those with the G/G genotype. This association was particularly pronounced in males in those carrying ABCG2 rs2231143 T/T genotype having a 4.47-fold (95 % CI = 1.02-19.67) increased risk after adjusting for covariates. There were no overall significant associations between AF risk and the polymorphisms of ABCB1 rs4148738 and rs1128503.

CONCLUSION

A robust risk association between the ABCG2 rs2231142 T allele and AF in Asian populations, particularly in male adults, suggests that genetic testing for this polymorphism could be integrated into risk assessment models for AF.

Case report: Gouty renal abscess and gouty sacroiliitis associated with genetic variants of a young woman

Gout is a form of inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints, resulting from a disorder in purine metabolism. It occurs more frequently in men than in women prior to menopause and is rare in young women. Gout can lead to various health complications, with many patients experiencing a significant burden of chronic kidney disease (CKD) and joint deformities. The development of gout is influenced by a complex interplay of genetic, environmental, and lifestyle factors, with elevated serum MSU levels serving as a key risk factor for its onset. However, only 10% of individuals with hyperuricemia go on to develop clinical gout, and several susceptibility loci are associated with the condition. Here, we present a case of a young woman with gouty sacroiliitis and gouty nephropathy linked to susceptibility loci.

Gout: global epidemiology, risk factors, comorbidities and complications: a narrative review

BACKGROUND

Gout is one of the oldest known diseases and the most common form of inflammatory arthritis. The established risk factors for gout include hyperuricemia, chronic renal disease, genetic, alcohol consumption, dietary factors, diuretic use, hypertension, obesity, and metabolic syndrome. Patients with gout have an increased risk of all-cause mortality, particularly from cardiovascular disease, cancer, and infectious diseases. Gout is also associated with several complications, such as nephrolithiasis. This literature review describes the global epidemiology and trends associated with gout, before providing an overview of its risk factors and complications.

METHODS

This research used the narrative review method. Thorough searches were performed in PubMed and Google scholar, up to June 15, 2024, for articles that evaluated the risk factors, comorbidities or complications associated with gout. Moreover, we also included studies that reported the epidemiological characteristics or burden of gout at the global, regional, or national level.

RESULTS

Gout is more prevalent in developed countries, than in developing countries, although its prevalence is increasing globally. In addition, gout is much more prevalent among males than among females. Hyperuricemia has the largest role in the development of gout, although many risk factors contribute to the increasing prevalence of gout, including genes, several medications, and diet. Gout is associated with several comorbidities and complications, which need to be taken into consideration when managing gout. In recent years, gout has been found to be associated with several new comorbidities.

CONCLUSIONS

Our findings provide a comprehensive and informative overview that can be useful for the prevention, diagnosis, and management of gout.

Uric acid and metabolic syndrome: Importance of hyperuricemia cut-off

BACKGROUND

The relationship between HyperUricemia (HU) and Metabolic Sindrome (MS) and if Uric Acid (UA) should be inserted into MS definitions is a matter of debate. Aim of our study was to evaluate the correlation between UA and HU with Insulin Resistance (IR) and MS in a population of hypertensive patients. HU was defined with two cut-offs (the classic one of ≥6 mg/dL for women and ≥ 7 for men; the newly proposed URRAH one with ≥5.6 mg/dL for both sexes).

METHODS

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy). IR was defined through TG/HDL ratio and NCEP-ATP-III criteria were used for MS diagnosis.

RESULTS

MS was found in 33.6 % while HU affected 14.8 % of subjects according to the traditional cut-off and 35.9 % with the URRAH cut-off. 9.7 % (traditional cut-off) and 17.3 % (URRAH's threshold) of the subjects had both HU and MS. UA level was significantly higher in MS group (5.7 vs 4.9 mg/dL, p < 0.0001) as well as for HU (29.0 vs 7.6 % and 51.6 vs 28.0 %, for classic and URRAH cut-off respectively, p < 0.0001 for both comparison). Logistic multivariable regression models showed that UA is related to MS diagnosis (OR = 1.608 for each 1 mg/dL), as well as HU with both cut-off (OR = 5.532 and OR = 3.379, p < 0.0001 for all comparison, for the classic cut-off and the URRAH one respectively).

CONCLUSIONS

The main finding of our study is that UA and HU significantly relate to IR and MS. The higher the values of UA and the higher the cut-off used, the higher the strength of the relationship.

Evaluating the Overall Safety of Glucokinase Activators in Patients with Type 2 Diabetes Mellitus

Purpose

This study aimed to assess the overall clinical adverse events (AEs) associated with glucokinase activators (GKAs) in patients with type 2 diabetes mellitus (T2DM).

Methods

We searched MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov databases from their dates of inception to June 6, 2023, for randomized controlled trials (RCTs) that reported safety data for GKAs in patients with T2DM. A random-effects model was used to obtain a summary odds ratio (OR) with associated 95% Confidence Intervals (CIs). Pre-specified subgroup analyses were conducted according to individual GKAs (dorzagliatin and all other GKAs), various controls, follow-up duration, mean duration of diabetes, and the location of clinical research.

Results

17 RCTs enrolling 4,918 patients (3,196 patients received GKAs and 1,722 patients received placebo or other hypoglycemic drugs) were identified. Among the 17 RCTs, dorzagliatin, AZD1656 and MK-0941 in three trials (1,541 patients), five trials (885 patients), and three trials (798 patients), respectively. GKA treatment was associated with a higher risk of any AEs (OR 1.220, 95% CI 1.072-1.389), mild AEs (OR 1.373, 95% CI 1.085-1.738), hyperlipidemia (OR 1.532, 95% CI 1.071-2.189), and hyperuricemia (OR 2.768, 95% CI 1.562-4.903) compared to patients in the control groups. The higher risks of any AEs were mainly attributed to dorzagliatin and MK-0941 and mild AEs mainly attributed to dorzagliatin. Notably, dorzagliatin had significant effects on the occurrence of hyperlipidemia (OR 1.476, 95% CI 1.025-2.126) and hyperuricemia (OR 2.727, 95% CI 1.523-4.883) in the subgroup analyses. No significant effects were detected from other GKAs when regarding hyperlipidemia and hyperuricemia.

Conclusion

The results of our meta-analysis indicated that GKAs were associated with a higher risk of any AEs, mild AEs, hyperlipidemia, and hyperuricemia. Further subgroup analyses revealed that the increased occurrence of hyperlipidemia, and hyperuricemia mainly originated from dorzagliatin treatment.

Investigating the causal association between serum uric acid levels and gastric cancer risk: a Mendelian randomization study

The causal link between serum uric acid (SUA) levels and gastric cancer susceptibility remains inadequately elucidated. This investigation employed a two-sample Mendelian randomization (MR) framework to assess the potential causative link between SUA concentrations and the propensity for developing gastric cancer. To further explore potential racial differences, this MR analysis was conducted on cohorts of both European and East Asian descent. Data from a large-scale GWAS in 343,836 Europeans and 92,615 East Asians were screened for 206 and 45 SNPs significantly linked to SUA levels, respectively, as genetic variants. Subsequently, four distinct MR methodologies were deployed to determine how SUA levels affected gastric cancer risk. Using the fixed-effects IVW approach, our analysis revealed no significant association between SUA levels and gastric cancer risk, with P-values exceeding the threshold of significance in both populations (European P = 0.778; East Asian P = 0.245). The findings were supported by three additional MR methods. The reliability of these results was substantiated by comprehensive sensitivity analyses. In summary, our data do not support a significant causal linkage between SUA levels and gastric cancer risk.

Recent Advances on the Regulations of Organic Anion Transporters

The organic anion transporter (OAT) family of over 10 members within the solute carrier (SLC) superfamily of membrane proteins plays critical roles in facilitating the flux of negatively charged molecules in and out of cell membranes. These anionic molecules include various endogenous and exogenous compounds such as signaling molecules, nutrients, metabolites, toxins, and drugs. Therefore, OATs actively contribute to the systemic homeostasis and efficacy of therapeutics. This article provides a brief overview on recent advances in the understanding of the regulatory mechanisms that control the expression and activity of OATs in both health and diseases.

A combination of red and processed meat intake and polygenic risk score influences the incidence of hyperuricemia in middle-aged Korean adults

BACKGROUND/OBJECTIVES

The high consumption of purine-rich meat is associated with hyperuricemia. However, there is limited evidence linking the consumption of red and processed meat to the genetic risk of hyperuricemia. We investigated the relationship between various combinations of red and processed meat consumption and the polygenic risk scores (PRSs) and the incidence of hyperuricemia in middle-aged Koreans.

SUBJECTS/METHODS

We analyzed the data from 44,053 participants aged ≥40 years sourced from the Health Examinees (HEXA) cohort of the Korean Genome and Epidemiology Study (KoGES). Information regarding red and processed meat intake was obtained using a semiquantitative food frequency questionnaire (SQ-FFQ). We identified 69 independent single-nucleotide polymorphisms (SNPs) at uric acid-related loci using genome-wide association studies (GWASs) and clumping analyses. The individual PRS, which is the weighted sum of the effect size of each allele at the SNP, was calculated. We used multivariable Cox proportional hazards models adjusted for covariates to determine the relationship between red and processed meat intake and the PRS in the incidence of hyperuricemia.

RESULTS

During an average follow-up period of 5 years, 2,556 patients with hyperuricemia were identified. For both men and women, the group with the highest red and processed meat intake and the highest PRS was positively associated with the development of hyperuricemia when compared with the group with the lowest red and processed meat intake and the lowest PRS (hazard ratio [HR], 2.72; 95% confidence interval [CI], 2.10-3.53; P < 0.0001; HR, 3.28; 95% CI, 2.45-4.40; P < 0.0001).

CONCLUSION

Individuals at a high genetic risk for uric acid levels should moderate their consumption of red and processed meat to prevent hyperuricemia.

Impact of Chronic Kidney Disease and Gout on End-Stage Renal Disease in Type 2 Diabetes: Population-Based Cohort Study

BACKGRUOUND

We examined the impact of gout on the end-stage renal disease (ESRD) risk in patients with type 2 diabetes mellitus (T2DM) and determined whether this association differs according to chronic kidney disease (CKD) status.

METHODS

Using the Korean National Health Insurance Service, this nationwide cohort study enrolled 847,884 patients with T2DM who underwent health checkups in 2009. Based on the presence of CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) and gout (two outpatient visits or one hospitalization within 5 years), patients were classified into four groups: CKD-Gout-, CKD- Gout+, CKD+Gout-, and CKD+Gout+. Patients with incident ESRD were followed up until December 2018.

RESULTS

Among 847,884 patients, 11,825 (1.4%) experienced progression to ESRD. ESRD incidence increased in the following order: 0.77 per 1,000 person-years (PY) in the CKD-Gout- group, 1.34/1,000 PY in the CKD-Gout+ group, 8.20/1,000 PY in the CKD+Gout- group, and 23.06/1,000 PY in the CKD+Gout+ group. The presence of gout modified the ESRD risk in a status-dependent manner. Hazard ratios (HR) were 1.49 (95% confidence interval [CI], 1.32 to 1.69) and 2.24 (95% CI, 2.09 to 2.40) in patients without and with CKD, respectively, indicating a significant interaction (P<0.0001). The CKD+Gout+ group had a markedly higher risk of developing ESRD (HR, 18.9; 95% CI, 17.58 to 20.32) than the reference group (CKD-Gout-).

CONCLUSION

Gout substantially enhances the risk of ESRD, even in the absence of CKD. Concurrent CKD and gout synergistically increase the risk of ESRD. Therefore, physicians should carefully screen for hyperuricemia to prevent progression to ESRD.

Association between Visceral Adiposity Index and Hyperuricemia among Steelworkers: The Moderating Effects of Drinking Tea

BACKGROUND/OBJECTIVES

Steelworkers are more likely to have a higher prevalence of hyperuricemia due to their exposure to special occupational factors and dietary habits. The interrelationships of visceral adiposity index (VAI), hyperuricemia, and drinking tea remain uncertain. This study aimed to assess the association between VAI and hyperuricemia among steelworkers, and if drinking tea modified this association.

METHODS

A total of 9928 steelworkers from Hunan Hualing Xiangtan Iron and Steel Company participated in this cross-sectional study. All participants completed a questionnaire, received anthropometric measurements, and provided blood samples for biochemical testing. Three logistic regression models were used to analyze the association between VAI and hyperuricemia.

RESULTS

In this study, the prevalence of hyperuricemia was approximately 23.74% (males: 24.41%; females: 20.63%), and a positive correlation between VAI and hyperuricemia risk was observed. In multivariate logistic regression analysis, the risk of hyperuricemia increased 1.76 times (95% CI: 1.64-1.89) and 2.13 times (95% CI: 1.76-2.57) with the increase of ln VAI in males and females, respectively. For males, compared to quartile 1, the risk of hyperuricemia in the second, third, and fourth quartile of VAI were 1.75 (95% CI: 1.11-2.71), 2.56 (95% CI: 1.67-3.93) and 4.89 (95% CI: 3.22-7.43). For females, compared to quartile 1, the risk of hyperuricemia in the second, third, and fourth quartile of VAI were 1.99 (95% CI: 1.40-2.82), 2.92 (95% CI: 1.96-4.34) and 4.51 (95% CI: 2.89-7.02). Additionally, our study found that, compared with not consuming tea, drinking tea could reduce uric acid levels by 0.014 in male steelworkers (t = -2.051, p = 0.040), 0.020 in workers consuming smoked food (t = -2.569, p = 0.010), and 0.022 in workers consuming pickled food (t = -2.764, p = 0.006).

CONCLUSIONS

In conclusion, VAI is positively correlated with hyperuricemia in steelworkers. Drinking tea may lower uric acid levels in male steelworkers and steelworkers who prefer smoked and pickled foods.

Association Between Serum Uric Acid Levels and Metabolic-Associated Fatty Liver Disease in Southeast China: A Cross-Sectional Study

Objective

This study aimed to explore the association between serum uric acid (sUA) levels and metabolic-associated fatty liver disease (MAFLD) in Southeast China.

Methods

We performed a cross-sectional study of 2605 subjects who underwent physical examination between 2015 and 2017 in Southeast China. To explore the association between sUA levels and the risk of MAFLD, we employed logistic regression, restricted cubic spline (RCS), subgroups and multiplicative interaction analysis.

Results

Logistic regression analysis showed a positive association between sUA and MAFLD [aOR total population (95% CI)= 1.90 (1.49 ~ 2.42)], [aOR male (95% CI)= 2.01 (1.54 ~ 2.62)], [aOR female (95% CI)= 1.15 (0.62 ~ 2.11)], respectively. The RCS plot presented a significant nonlinear dose-response relationship between sUA levels and MAFLD risk, and the risk of MAFLD increased significantly when sUA> 5.56 mg/dL (P nonlinear< 0.001). Subgroups analysis revealed that the positive association between sUA and MAFLD was consistent across strata of gender, age, BMI, drinking status, smoking status and tea drinking status. Significant associations between sUA and MAFLD were not only found in males but also existed in subjects whose age ≤60, BMI ≥24 kg/m2, drinkers, smokers and tea-drinkers. Adjusted ORs were estimated to be 2.01, 1.95, 2.11, 2.29, 2.64 and 2.20, respectively. Multiplicative interactions were not observed between gender, age, drinking status, smoking status, tea drinking status and sUA (all P interaction> 0.05).

Conclusion

According to our study, sUA was positively associated with the risk of MAFLD. Additionally, the risk of MAFLD increased significantly when sUA levels exceeded 5.56 mg/dL. Our study may help clarify whether sUA plays a diagnostic role in MAFLD.

Association of Functional Genetic Variations in Uric Acid Transporters with the Risk of Idiopathic Male Infertility: A Genetic Association Study and Bioinformatic Analysis

Uric acid plays an important role in sustaining and improving sperm morphology, viability, and motility. It is known that SLC2A9 and ABCG2 protein are the main urate transporter and genetic variations in these genes could be associated with the levels of serum uric acid. This study aimed to investigate the association between single-nucleotide polymorphisms (SNPs) SLC2A9-rs16890979, SLC2A9-rs3733591, ABCG2-rs2231142, and ABCG2-rs2231137 with male infertility. Additionally, the correlation of these SNPs with the uric acid level in seminal plasma of infertile men was examined. Subsequently, an in silico analysis was performed. In a case-control study, 193 infertile and 154 healthy controls were recruited. After semen sample collection, the uric acid level of seminal plasma was measured by a commercial kit. After genomic DNA extraction from sperm samples, SNPs genotyping was performed by PCR-RFLP method. Lastly, the effects of SNPs on the SLC2A9 and ABCG2 gene function were evaluated by bioinformatics tools. The genetic association study revealed that there are significant associations between rs16890979, rs3733591, rs2231142, and rs2231137 genetic variations and increased risk of male infertility. Also, these variations were associated with oligozoospermia and teratozoospermia, and sometimes with asthenozoospermia. Also, we found that four studied SNPs could be associated with a decreased level of uric acid of seminal plasma in teratozoospermia and asthenozoospermia. Bioinformatic analysis revealed that the mentioned polymorphisms could affect molecular aspects of SLC2A9 and ABCG2 genes. In this preliminary study, the rs16890979, rs3733591, rs2231142, and rs2231137 genetic variations could be considered as genetic risk factors for male infertility by interfering with the uric acid level of seminal plasma.

A phenome-wide association and factorial Mendelian randomization study on the repurposing of uric acid-lowering drugs for cardiovascular outcomes

Uric acid has been linked to various disease outcomes. However, it remains unclear whether uric acid-lowering therapy could be repurposed as a treatment for conditions other than gout. We first performed both observational phenome-wide association study (Obs-PheWAS) and polygenic risk score PheWAS (PRS-PheWAS) to identify associations of uric acid levels with a wide range of disease outcomes. Then, trajectory analysis was conducted to explore temporal progression patterns of the observed disease outcomes. Finally, we investigated whether uric acid-lowering drugs could be repurposed using a factorial Mendelian randomization (MR) study design. A total of 41 overlapping phenotypes associated with uric acid levels were identified by both Obs- and PRS- PheWASs, primarily cardiometabolic diseases. The trajectory analysis illustrated how elevated uric acid levels contribute to cardiometabolic diseases, and finally death. Meanwhile, we found that uric acid-lowering drugs exerted a protective role in reducing the risk of coronary atherosclerosis (OR = 0.96, 95%CI: 0.93, 1.00, P = 0.049), congestive heart failure (OR = 0.64, 95%CI: 0.42, 0.99, P = 0.043), occlusion of cerebral arteries (OR = 0.93, 95%CI: 0.87, 1.00, P = 0.044) and peripheral vascular disease (OR = 0.60, 95%CI: 0.38, 0.94, P = 0.025). Furthermore, the combination of uric acid-lowering therapy (e.g. xanthine oxidase inhibitors) with antihypertensive treatment (e.g. calcium channel blockers) exerted additive effects and was associated with a 6%, 8%, 8%, 10% reduction in risk of coronary atherosclerosis, heart failure, occlusion of cerebral arteries and peripheral vascular disease, respectively. Our findings support a role of elevated uric acid levels in advancing cardiovascular dysfunction and identify potential repurposing opportunities for uric acid-lowering drugs in cardiovascular treatment.

A scalable and robust variance components method reveals insights into the architecture of gene-environment interactions underlying complex traits

Understanding the contribution of gene-environment interactions (GxE) to complex trait variation can provide insights into disease mechanisms, explain sources of heritability, and improve genetic risk prediction. While large biobanks with genetic and deep phenotypic data hold promise for obtaining novel insights into GxE, our understanding of GxE architecture in complex traits remains limited. We introduce a method to estimate the proportion of trait variance explained by GxE (GxE heritability) and additive genetic effects (additive heritability) across the genome and within specific genomic annotations. We show that our method is accurate in simulations and computationally efficient for biobank-scale datasets. We applied our method to common array SNPs (MAF ≥1%), fifty quantitative traits, and four environmental variables (smoking, sex, age, and statin usage) in unrelated white British individuals in the UK Biobank. We found 68 trait-E pairs with significant genome-wide GxE heritability (p<0.05/200) with a ratio of GxE to additive heritability of ≈6.8% on average. Analyzing ≈8 million imputed SNPs (MAF ≥0.1%), we documented an approximate 28% increase in genome-wide GxE heritability compared to array SNPs. We partitioned GxE heritability across minor allele frequency (MAF) and local linkage disequilibrium (LD) values, revealing that, like additive allelic effects, GxE allelic effects tend to increase with decreasing MAF and LD. Analyzing GxE heritability near genes highly expressed in specific tissues, we find significant brain-specific enrichment for body mass index (BMI) and basal metabolic rate in the context of smoking and adipose-specific enrichment for waist-hip ratio (WHR) in the context of sex.

Hyperuricemia Subtypes Classified According to Renal Uric Acid Handling Manifesting Distinct Phenotypic and Genetic Profiles in People With Gout

OBJECTIVE

Hyperuricemia can be stratified into four subtypes according to renal uric acid handling. The aim of this study was to comprehensively describe the biologic characteristics (including genetic background) of clinically defined hyperuricemia subtypes in two large geographically independent gout cohorts.

METHODS

Hyperuricemia subtype was defined as renal uric acid overload (ROL), renal uric acid underexcretion (RUE), combined, or renal normal. Twenty single nucleotide polymorphisms (SNPs) previously identified as gout risk loci or associated with serum urate (SU) concentration in the East Asian population were genotyped. Weighted polygenic risk scores were calculated to assess the cumulative effect of genetic risks on the subtypes.

RESULTS

Of the 4,873 participants, 8.8% had an ROL subtype, 60.9% RUE subtype, 23.1% combined subtype, and 7.2% normal subtype. The ROL subtype was independently associated with older age at onset, lower SU, tophi, and diabetes mellitus; RUE was associated with lower body mass index (BMI) and non-diabetes mellitus; the combined subtype was associated with younger age at onset, higher BMI, SU, estimated glomerular filtration rate (eGFR), and smoking; and the normal subtype was independently associated with older age at onset, lower SU, and eGFR. Thirteen SNPs were associated with gout with 6 shared loci and subtype-dependent risk loci patterns. High polygenic risk scores were associated with ROL subtype (odds ratio [OR] = 9.63, 95% confidence interval [95% CI] 4.53-15.12), RUE subtype (OR = 2.18, 95% CI 1.57-3.03), and combined subtype (OR = 6.32, 95% CI 4.22-9.48) compared with low polygenic risk scores.

CONCLUSION

Hyperuricemia subtypes classified according to renal uric acid handling have subtype-specific clinical and genetic features, suggesting subtype-unique pathophysiologic mechanisms.

A Genome-Wide Association Study of Oxypurinol Concentrations in Patients Treated with Allopurinol

Cohort studies have identified several genetic determinants that could predict the clinical response to allopurinol. However, they have not been commonly used for genome-wide investigations to identify genetic determinants on allopurinol metabolism and concentrations. We conducted a genome-wide association study of a prior cross-sectional investigation of patients from the Montreal Heart Institute Biobank undergoing allopurinol therapy. Four endpoints were investigated, namely plasma concentrations of oxypurinol, the active metabolite of allopurinol, allopurinol, and allopurinol-riboside, as well as allopurinol daily dosing. A total of 439 participants (mean age 69.4 years; 86.4% male) taking allopurinol (mean daily dose 194.5 mg) and who had quantifiable oxypurinol concentrations were included in the genome-wide analyses. Participants presented with multiple comorbidities and received concomitant cardiovascular medications. No association achieved the predefined genome-wide threshold values for any of the endpoints (all p > 5 × 10-8). Our results are consistent with prior findings regarding the difficulty in identifying genetic determinants of drug concentrations or pharmacokinetics of allopurinol and its metabolites, as well as allopurinol daily dosing. Given the size of this genome-wide study, collaborative investigations involving larger and diverse cohorts may be required to further identify pharmacogenomic determinants of allopurinol and measure their clinical relevance to personalize allopurinol therapy.

Association between Glycosylated Hemoglobin and Serum Uric Acid: A US NHANES 2011-2020

Background

Serum uric acid (SUA) and glycosylated hemoglobin (HbA1c) were closely related to the body's metabolism. This study aimed to investigate the relationship between HbA1c and SUA in adults.

Methods

This study selected 7293 participants aged ≥20 from 2011 to 2020 in the National Health and Nutrition Examination Survey (NHANES). The multivariate linear regression model was used to test the association between HbA1c and SUA. Subgroup analysis was performed according to age, gender, race, and body mass index (BMI). This study solved the relationship between HbA1c and SUA by fitting a smooth curve. Finally, the inflection point in the nonlinear relationship was calculated by the recursive algorithm, and the relationship between HbA1c and SUA on both sides of the inflection point was analyzed by the two-segment piecewise linear regression model.

Results

All 7293 participants found a negative correlation between HbA1c and SUA by completely adjusting the model (β = -7.93 and 95% CI: -9.49--6.37). In addition, when this study was stratified by gender, age, race, and BMI status, this negative correlation was still statistically significant. In the subgroup analysis, we found that the relationship between the two had different results due to gender differences. In men, HbA1c had a significant negative correlation with SUA. However, in women, the HbA1c value was positively correlated with SUA before 6.8%, and the HbA1c value was negatively correlated with SUA after 6.8%, which indicates that the relationship between HbA1c and SUA in women has changed in prediabetes and diabetes.

Conclusion

This study shows that HbA1c is positively correlated with SUA in American adults before 7%. There is a negative correlation after the HbA1c value of 7%.

Pathophysiology and Treatment of Gout Arthritis; including Gout Arthritis of Hip Joint: A Literature Review

Gout is triggered by the accumulation of uric acid in the body, leading to hyperuricemia. Genetic, metabolic, and environmental factors can influence this condition. Excessive uric acid buildup results in the formation of monosodium urate (MSU) crystals, which precipitate in specific areas of the body, including the joints, where they can cause symptoms of gout. While the acute and chronic symptoms of gout have been well-documented, diagnosis of gout affecting the hip joint poses significant challenges. The global incidence of gout, the most prevalent form of inflammatory arthritis, is on the rise. Evaluation of the clinical signs, laboratory results, and imaging results is generally required for diagnosis of gout in cases where MSU crystals have not been detected. Hyperuricemia is considered a primary cause of arthritis symptoms, and comprehensive guidelines for treatment are available. Therefore, the choice of medication is straightforward, and moderate effectiveness of treatment has been demonstrated. Gout is a chronic disease, requiring lifelong uric acid-lowering medications, thus application of a treatment strategy based on the target blood uric acid concentration is necessary. Consequently, cases of gout will likely be observed more frequently by hip surgeons in clinical scenarios in the future. The objective of this review is to provide an overview of the pathophysiology of gout and subsequently examine recent advances in diagnostic methods and therapeutic agents based on an understanding of its underlying mechanisms. In addition, literature on gout-related issues affecting the hip joint, providing a useful reference for hip surgeons is examined.

Molecular characteristic analysis of single-nucleotide polymorphisms in SLC16A9/hMCT9

AIMS

Human monocarboxylate transporter 9 (hMCT9), encoded by SLC16A9, is a transporter that mediates creatine transport across the transmembrane. Previously, we reported that hMCT9 is an extracellular pH- and Na+-sensitive creatine transporter with two kinetic components. Recently, some variants of hMCT9 have been found to be associated with serum uric acid levels, hyperuricemia, and gout. Among these, two single-nucleotide polymorphisms (SNPs) have also been reported: rs550527563 (L93M) and rs2242206 (T258K). However, the effect of these SNPs on hMCT9 transport activity remains unclear. This study aimed to determine the influence of hMCT9 L93M and T258K on transport characteristics.

MAIN METHODS

hMCT9 L93M and T258K were constructed by site-directed mutagenesis and expressed in Xenopus laevis oocyte. Transport activity of uric acid and creatine via hMCT9 were measured by using a Xenopus laevis oocyte heterologous expression system.

KEY FINDINGS

We assessed the transport activity of uric acid and creatine, and observed that hMCT9-expressing oocytes transported uric acid approximately 3- to 4-fold more than water-injected oocytes. hMCT9 L93M slightly reduced the transport activity of creatine, whereas hMCT9 T258K did not affect the transport activity. Interestingly, hMCT9 T258K abolished Na+ sensitivity and altered the substrate affinity from two components to one.

SIGNIFICANCE

In conclusion, hMCT9 SNPs affect transport activity and characteristics. hMCT9 L93M and T258K may induce dysfunction and contribute to pathologies such as hyperuricemia and gout. This is a first study to evaluate molecular characteristics of hMCT9 SNPs.

GLUT9 as a potential drug target for chronic kidney disease: Drug target validation by a Mendelian randomization study

Although chronic kidney disease (CKD) is recognized as a major public health concern, effective treatment strategies have yet to be developed. Identification and validation of drug targets are key issues in the development of therapeutic agents for CKD. Uric acid (UA), a major risk factor for gout, has also been suggested to be a risk factor for CKD, but the efficacy of existing urate-lowering therapies for CKD is controversial. We focused on five uric acid transporters (ABCG2, SLC17A1, SLC22A11, SLC22A12, SLC2A9) as potential drug targets and evaluated the causal association between serum UA levels and estimated glomerular filtration rate (eGFR) using single-SNP Mendelian Randomization. The results showed a causal association between genetically predicted changes in serum UA levels and eGFR when genetic variants were selected from the SLC2A9 locus. Estimation based on a loss-of-function mutation (rs16890979) showed that the changes in eGFR per unit increase in serum UA level was -0.0082 ml/min/1.73 m2 (95% CI -0.014 to -0.0025, P = 0.0051). These results indicate that SLC2A9 may be a novel drug target for CKD that preserves renal function through its urate-lowering effect.

Population pharmacokinetics, pharmacodynamics and pharmacogenetics modelling of oxypurinol in Hmong adults with gout and/or hyperuricemia

AIMS

The aim of this study was to quantify identifiable sources of variability, including key pharmacogenetic variants in oxypurinol pharmacokinetics and their pharmacodynamic effect on serum urate (SU).

METHODS

Hmong participants (n = 34) received 100 mg allopurinol twice daily for 7 days followed by 150 mg allopurinol twice daily for 7 days. A sequential population pharmacokinetic pharmacodynamics (PKPD) analysis with non-linear mixed effects modelling was performed. Allopurinol maintenance dose to achieve target SU was simulated based on the final PKPD model.

RESULTS

A one-compartment model with first-order absorption and elimination best described the oxypurinol concentration-time data. Inhibition of SU by oxypurinol was described with a direct inhibitory Emax model using steady-state oxypurinol concentrations. Fat-free body mass, estimated creatinine clearance and SLC22A12 rs505802 genotype (0.32 per T allele, 95% CI 0.13, 0.55) were found to predict differences in oxypurinol clearance. Oxypurinol concentration required to inhibit 50% of xanthine dehydrogenase activity was affected by PDZK1 rs12129861 genotype (-0.27 per A allele, 95% CI -0.38, -0.13). Most individuals with both PDZK1 rs12129861 AA and SLC22A12 rs505802 CC genotypes achieve target SU (with at least 75% success rate) with allopurinol below the maximum dose, regardless of renal function and body mass. In contrast, individuals with both PDZK1 rs12129861 GG and SLC22A12 rs505802 TT genotypes would require more than the maximum dose, thus requiring selection of alternative medications.

CONCLUSIONS

The proposed allopurinol dosing guide uses individuals' fat-free mass, renal function and SLC22A12 rs505802 and PDZK1 rs12129861 genotypes to achieve target SU.

The Role of Uric Acid in Human Health: Insights from the Uricase Gene

Uric acid is the final product of purine metabolism and is converted to allantoin in most mammals via the uricase enzyme. The accumulation of loss of function mutations in the uricase gene rendered hominoids (apes and humans) to have higher urate concentrations compared to other mammals. The loss of human uricase activity may have allowed humans to survive environmental stressors, evolution bottlenecks, and life-threatening pathogens. While high urate levels may contribute to developing gout and cardiometabolic disorders such as hypertension and insulin resistance, low urate levels may increase the risk for neurodegenerative diseases. The double-edged sword effect of uric acid has resurrected a growing interest in urate's antioxidant role and the uricase enzyme's role in modulating the risk of obesity. Characterizing both the effect of uric acid levels and the uricase enzyme in different animal models may provide new insights into the potential therapeutic benefits of uric acid and novel uricase-based therapy.

Glucokinase regulatory protein: a balancing act between glucose and lipid metabolism in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease worldwide, affected by both genetics and environment. Type 2 diabetes (T2D) stands as an independent environmental risk factor that precipitates the onset of hepatic steatosis and accelerates its progression to severe stages of liver damage. Furthermore, the coexistence of T2D and NAFLD magnifies the risk of cardiovascular disease synergistically. However, the association between genetic susceptibility and metabolic risk factors in NAFLD remains incompletely understood. The glucokinase regulator gene (GCKR), responsible for encoding the glucokinase regulatory protein (GKRP), acts as a regulator and protector of the glucose-metabolizing enzyme glucokinase (GK) in the liver. Two common variants (rs1260326 and rs780094) within the GCKR gene have been associated with a lower risk for T2D but a higher risk for NAFLD. Recent studies underscore that T2D presence significantly amplifies the effect of the GCKR gene, thereby increasing the risk of NASH and fibrosis in NAFLD patients. In this review, we focus on the critical roles of GKRP in T2D and NAFLD, drawing upon insights from genetic and biological studies. Notably, prior attempts at drug development targeting GK with glucokinase activators (GKAs) have shown potential risks of augmented plasma triglycerides or NAFLD. Conversely, overexpression of GKRP in diabetic rats improved glucose tolerance without causing NAFLD, suggesting the crucial regulatory role of GKRP in maintaining hepatic glucose and lipid metabolism balance. Collectively, this review sheds new light on the complex interaction between genes and environment in NAFLD, focusing on the GCKR gene. By integrating evidence from genetics, biology, and drug development, we reassess the therapeutic potential of targeting GK or GKRP for metabolic disease treatment. Emerging evidence suggests that selectively activating GK or enhancing GK-GKRP binding may represent a holistic strategy for restoring glucose and lipid metabolic balance.

Comparison Between Early-Onset and Common Gout: A Systematic Literature Review

INTRODUCTION

Gout is an inflammatory, metabolic disease associated with a high comorbidity burden including cardiovascular disease, hypertension, type 2 diabetes, hyperlipidemia, renal disease, and metabolic syndrome. Approximately 9.2 million Americans have gout, making prognosis and treatment outcome predictors highly important. About 600,000 Americans have early-onset gout (EOG), generally defined as first gout attack at ≤ 40 years of age. However, data on EOG clinical features, comorbidity profile, and treatment response are sparse; this systematic literature review provides insight.

METHODS

PubMed and American College of Rheumatology (ACR)/European Alliance of the Associations for Rheumatology (EULAR) abstract archives were searched for early-onset gout, "early onset gout," and ("gout" AND "age of onset"). Duplicate, foreign language, single case report, older (before 2016), and irrelevant/data insufficient publications were excluded. The age of diagnosis categorized patients as having common gout (CG, generally > 40 years) or EOG (generally ≤ 40 years). Applicable publications were extensively reviewed/discussed among authors for inclusion/exclusion consensus.

RESULTS

A total of 283 publications were identified, with 46 (35 articles, 10 abstracts) reviewed and 17 (12 articles, 5 abstracts) ultimately included. Eleven reported clinical characteristics, with 6 EOG-CG retrospective/cross-sectional comparisons. Gout diagnosis preceded cardiometabolic comorbidity and renal comorbidities were less prevalent in EOG than CG patients. EOG patients had more severe disease (more gout flares, polyarticular disease), higher pre-therapy serum urate (SU), and worse oral urate-lowering therapy response. Genetics-focused publications reported higher incidences of dysfunctional urate transporter mutations in EOG patients.

CONCLUSIONS

This review suggests that EOG is more recalcitrant to urate-lowering therapy, is associated with urate transporter defects, and carries heavy disease burden. Therefore, early rheumatology referral and urate-lowering in a treat-to-target fashion may benefit EOG patients. Interestingly, EOG patients had fewer cardiometabolic comorbidities at diagnosis than CG patients, presenting a potential "window of opportunity" to attenuate cardiometabolic comorbidity development with SU control. Preventing gout-related suffering and health burden is particularly important in these young EOG patients who will live with gout and its sequelae for decades.

Serum uric acid and left ventricular mass index independently predict cardiovascular mortality: The uric acid right for heart health (URRAH) project

A relationship between serum uric acid (SUA) and cardiovascular (CV) events has been documented in the Uric Acid Right for Heart Health (URRAH) study.

AIM

of this study was to investigate the association between SUA and left ventricular mass index (LVMI) and whether SUA and LVMI or their combination may predict the incidence of CV death.

METHODS

Subjects with echocardiographic measurement of LVMI included in the URRAH study (n=10733) were part of this analysis. LV hypertrophy (LVH) was defined as LVMI > 95 g/m2 in women and 115 g/m2 in men.

RESULTS

A significant association between SUA and LVMI was observed in multiple regression analysis in men: beta 0,095, F 5.47, P< 0.001 and women: beta 0,069, F 4.36, P<0.001. During follow-up 319 CV deaths occurred. Kaplan-Meier curves showed a significantly poorer survival rate in subjects with higher SUA (> 5.6 mg/dl in men and 5.1 mg/dl in women) and LVH (log-rank chi-square 298.105; P<0.0001). At multivariate Cox regression analysis in women LVH alone and the combination of higher SUA and LVH but not hyperuricemia alone, were associated with a higher risk of CV death, while in men hyperuricemia without LVH, LVH without hyperuricemia and their combination were all associated with a higher incidence of CV death.

CONCLUSIONS

Our findings demonstrate that SUA is independently associated with LVMI and suggest that the combination of hyperuricemia with LVH is an independent and powerful predictor for CV death both in men and women.

Sex differences in the association between urate metabolism and kidney outcomes in patients with chronic kidney disease

BACKGROUND

The association between serum uric acid (SUA) concentration and kidney outcomes in patients with chronic kidney disease (CKD) is controversial. Furthermore, there are no reports regarding the association of clearance of uric acid (CUA) with kidney outcomes. We aimed to determine whether SUA or CUA was associated with kidney outcomes in patients with CKD stratified by sex.

METHODS

The present prospective study was conducted in 815 patients (523 men and 292 women) with CKD. The participants were divided into quartiles (Q1-Q4) of SUA or CUA for each sex. Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death (outcome 1) and a composite of doubling of SCr or ESKD (outcome 2).

RESULTS

During a median follow-up of 2.5 years, outcomes 1 and 2 occurred in 363 and 321 patients, respectively. Multivariable-adjusted Cox analyses showed that in men, the hazard ratios (95% confidence intervals) for outcome 1 of Q1, Q2, and Q3 of CUA were 2.08 (1.18-3.70), 2.03 (1.22-3.39), and 1.85 (1.17-2.95), respectively, compared with Q4. Additionally, there were similar associations between lower CUA quartiles and outcome 2 in men. However, no associations between SUA and either outcome were observed in men. Conversely, in women, neither SUA nor CUA was associated with an outcome.

CONCLUSION

In CKD, lower CUA was independently associated with poor kidney outcomes only in men, and in both sexes, there was no association of SUA with kidney outcomes.

Combining body mass index and waist height ratio to assess the relationship between obesity and serum uric acid levels in adolescents

Background

The study aims to explore the relationship between obesity and serum uric acid in adolescents by combining body mass index and waist height ratio.

Methods

475 adolescents in our study were classified as normal weight without central obesity (NW), normal weight but central obesity (NWCO), overweight or obesity without central obesity (OB) and overweight or obesity with central obesity (OBCO). Odds ratios (OR) and 95% confidence intervals (CI) for hyperuricemia were calculated using a logistic regression model. The dose-response association between obesity indicators and serum uric acid were explored by restricted cubic spline model.

Results

The highest serum uric acid level and the OR for hyperuricemia were found in the OBCO group, regardless of sex. After controlling for waist height ratio, the risk of hyperuricemia increased with increasing body mass index in boys and girls. The restricted cubic spline model showed that boys had higher ORs for hyperuricemia at the 25th and 75th percentiles of body mass index than for waist height ratio and girls had a higher OR for hyperuricemia than waist height ratio at the 25th percentile of body mass index.

Conclusions

Hyperuricemia in adolescence was not only associated with the overweight or obesity in BMI, but with the combination of overweight or obesity in BMI and central obesity in WHtR. However, in boys and girls, the increased risk of hyperuricemia associated with elevated body mass index was significantly better than that of waist height ratio.

Association of serum uric acid-to-high-density lipoprotein cholesterol ratio with non-alcoholic fatty liver disease in American adults: a population-based analysis

Objective

Non-invasive disease indicators are currently limited and need further research due to the increased non-alcoholic fatty liver disease (NAFLD) prevalence worldwide. The serum uric acid-to-high-density lipoprotein cholesterol ratio (UHR) has been recognized as a novel inflammatory and metabolic marker. Herein, we explored the correlation between UHR and the risk of NAFLD in-depth.

Methods

A total of 3,766 participants were included in our survey, and the National Health and Nutrition Examination Survey (NHANES) 2017-2018 cycle provided the cross-sectional study population. Weighted multivariable logistic regression and multivariate linear regression analyses were performed to assess the association between the UHR and the odds of NAFLD and liver steatosis and fibrosis severity, respectively. Moreover, we explored the non-linear relationship between the UHR and NAFLD by the generalized additive model.

Results

NAFLD probabilities were statistically demonstrated to be positively correlated with the UHR (OR = 1.331 per SD increase, 95% CI: 1.100, 1.611). The positive connection of the UHR with NAFLD risk persisted significantly in female subjects but not in male subjects in subgroup analyses stratified by gender. The non-linear relationship analysis demonstrated that a UHR between ~20 and 30% suggested a saturation effect of NAFLD risk. Furthermore, a dramatically positive correlation was found between the UHR and hepatic steatosis severity but not fibrosis. Finally, the receiver operating characteristic analysis suggested that UHR had a better predictive value for NAFLD than either serum uric acid (sUA) or high-density lipoprotein cholesterol (HDL) alone [UHR (area under curve): 0.6910; 95% CI: 0.6737-0.7083; P < 0.0001].

Conclusion

Our investigation revealed that the elevated UHR level was independently related to an increased NAFLD risk and the severity of liver steatosis in American individuals. The correlation differed according to sex. This non-invasive indicator may enhance the capacity to predict the onset of NAFLD and may uncover alternative therapeutic interventional targets.

Evaluation of efficacy and safety of glucokinase activators-a systematic review and meta-analysis

Aims

Glucokinase activators (GKAs) promote the activity of glucokinase (GK) and is under development for the treatment of diabetes. The efficacy and safety of GKAs require evaluation.

Methods

This meta-analysis included randomized controlled trials (RCTs) with a duration of at least 12 weeks conducted in patients with diabetes. The primary objective of this meta-analysis was the difference of hemoglobin A1c (HbA1c) change from baseline to study end between GKA groups and placebo groups. Risk of hypoglycemia and laboratory indicators were also evaluated. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for the continuous outcomes, and odds ratios (ORs) and 95% CI were calculated for the risk of hypoglycemia.

Results

Data from 13 RCTs with 2,748 participants treated with GKAs and 2,681 control participants were analyzed. In type 2 diabetes, the level of HbA1c decreased greater in patients with GKA treatment compared with placebo (WMD = -0.339%, 95% CI -0.524 to -0.154%, P < 0.001). The OR comparing GKA versus placebo was 1.448 for risk of hypoglycemia (95% CI 0.808 to 2.596, P = 0.214). The WMD comparing GKA versus placebo was 0.322 mmol/L for triglyceride (TG) levels (95% CI 0.136 to 0.508 mmol/L, P = 0.001). When stratified by drug type, selectivity, and study duration, a significant difference was found between groups. In type 1 diabetes, the result of HbA1c change and lipid indicators showed no significant difference between the TPP399 group and the placebo group.

Conclusions

In patients with type 2 diabetes, GKA treatment was associated with a better glycemic control but a significant elevation in TG concentration in general. The efficacy and safety varied with drug type and selectivity.

Systematic review registration

International Prospective Register of Systematic Reviews, identifier CRD42022378342.

Hypouricemic Actions of the Pericarp of Mangosteen in Vitro and in Vivo

Hyperuricemia is the result of overproduction and/or underexcretion of uric acid, and it is a well-known risk factor for gout, hypertension, and diabetes. However, available drugs for hyperuricemia in the clinic are limited. Recently, a lot of research has been conducted in order to discover new uric acid-lowering agents from plants and foods. We found that the extracts from the pericarp of mangosteen reduced urate. Bioactivity-guided study showed that α-mangostin was the principal constituent. Herein, we reported for the first time the hypouricemic activities and underling mechanism of α-mangostin. The α-mangostin dose- and time-dependently decreased the levels of serum urate in hyperuricemic mice and markedly increased the clearance of urate in hyperuricemic rats, exhibiting a promotion of urate excretion in the kidney. Further evidence showed that α-mangostin significantly decreased the protein levels of GLUT9 in the kidneys. The change in the expression of URAT1 was not observed. Moreover, α-mangostin did not inhibit the activities of xanthine oxidoreductase and uricase in vitro or in vivo. Taken together, these findings suggest that α-mangostin has potential to be developed as a new anti-hyperuricemic agent with promoting uric acid excretion.

Interaction of sex and diabetes on the association between hemoglobin glycation index, hemoglobin A1c and serum uric acid

BACKGROUND

Hemoglobin glycation index (HGI), which is calculated by blood glucose and hemoglobin A1c(HbA1c), reflects the individual discrepancy in HbA1c. This study aimed to investigate the association between HGI/HbA1c and serum uric acid(SUA) stratified by sex and diabetes.

METHODS

The study recruited 33772 participants who underwent physical examinations between April 2016 and August 2021 in Beijing Chao-Yang Hospital. A random subsample of 3000 subjects was utilized to calculate the formula of HGI and data of the remaining 30772 participants were used for analysis. HGI and HbA1c were categorized according to quartiles (Q1, Q2, Q3, Q4), using Q1 as the reference. We used multiple linear regression and restricted cubic splines for data analysis.

RESULTS

30772 participants with a mean age of 44.4 years old were included in the analysis, 48.6% (N = 14944) of which were female and 7.7% (N = 2363) with diabetes. Associations of HGI, HbA1c and SUA were modified by sex and diabetes. The relationship between SUA levels and HGI was positive in women without diabetes, with one unit increase in HGI associating with an 11.3 μmol/L increase in SUA (P < 0.001) after adjusting for other confounders. On average, each one-unit increase in HbA1c was associated with a 14.3 μmol/L decrease in SUA in women with diabetes, a 14.9 μmol/L decrease in SUA in men with diabetes, and a 16.5 μmol/L increase in SUA in women without diabetes (all P < 0.001). The SUA levels in men without diabetes showed a bell-shaped relation with HbA1c, increasing as the HbA1c rose to around 5.7% and then falling with a further increase of HbA1c (P < 0.001).

CONCLUSIONS

SUA levels were inversely correlated with HbA1c in diabetic patients, also in men with prediabetes (HbA1c ≥ 5.7%), but positively correlated with HbA1c and HGI in women without diabetes. Glycemic control may help to reduce the risk of hyperuricemia in non-diabetes women.

Extract of Aster glehni ameliorates potassium oxonate-induced hyperuricemia by modulating renal urate transporters and renal inflammation by suppressing TLR4/MyD88 signaling

Recent studies suggest that Aster glehni extract (AGE) reduces hyperuricemia by preventing xanthine oxidase activity. However, its effect on renal urate transporters responsible for modulating urate excretion has not been examined. This study investigated whether AGE affects gene expressions of urate transporters using potassium oxonate (PO)-induced hyperuricemia rats. Furthermore, the underlying mechanisms of AGE were explored to ameliorate renal inflammation and injury by PO. AGE effectively restored PO-induced dysregulation of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), ATP-binding cassette transporter subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), and organic cation transporter 1 (OCT1), resulting in increasing urate excretion. Additionally, AGE suppressed toll-like receptor 4/myeloid differentiation factor 88 (TLR4/MyD88) signaling, phosphorylation of nuclear factor kappa B (NF-κB), and renal production of IFN-γ, IL-1β, TNF-α, and IL-6. These results suggest that AGE may ameliorate PO-induced hyperuricemia by modulating renal transporters, and further renal inflammation via inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01153-5.

Gene Dose-Dependent and Additive Effects of ABCG2 rs2231142 and SLC2A9 rs3733591 Genetic Polymorphisms on Serum Uric Acid Levels

This study aimed to evaluate whether the single nucleotide polymorphisms of ATP-binding cassette subfamily G member 2 (ABCG2) and solute carrier family 2 member 9 (SLC2A9) affect individual blood uric acid levels using pyrosequencing. ABCG2 (rs2231142, rs72552713, rs2231137), SLC2A9 (rs3734553, rs3733591, rs16890979), and individual uric acid levels were prospectively analyzed in 250 healthy young Korean male participants. Prominent differences in uric acid levels of the alleles were observed in the SLC2A9 rs3733591 polymorphism: wild-type (AA) vs. heterozygote (AG), 0.7 mg/dL (p < 0.0001); AA vs. mutant type (GG), 1.32 mg/dL (p < 0.0001); and AG vs. GG, 0.62 mg/dL (p < 0.01). In ABCG2 single nucleotide polymorphisms (SNPs), the statistically significant differences in uric acid levels were only found in rs2231142 between CC vs. AA (1.06 mg/dL; p < 0.001), and CC vs. CA (0.59 mg/dL; p < 0.01). Serum uric acid levels based on the ABCG2 and SLC2A9 diplotype groups were also compared. The uric acid levels were the lowest in the CC/AA diplotype and highest in the AA/AG diplotype. In addition, the SNP SLC2A9 rs3733591 tended to increase the uric acid levels when the ABCG2 rs2231142 haplotypes were fixed. In conclusion, both the ABCG2 rs2231142 and SLC2A9 rs3733591 polymorphisms may additively elevate blood uric acid levels.

New insight into the management of renal excretion and hyperuricemia: Potential therapeutic strategies with natural bioactive compounds

Hyperuricemia is the result of increased production and/or underexcretion of uric acid. Hyperuricemia has been epidemiologically associated with multiple comorbidities, including metabolic syndrome, gout with long-term systemic inflammation, chronic kidney disease, urolithiasis, cardiovascular disease, hypertension, rheumatoid arthritis, dyslipidemia, diabetes/insulin resistance and increased oxidative stress. Dysregulation of xanthine oxidoreductase (XOD), the enzyme that catalyzes uric acid biosynthesis primarily in the liver, and urate transporters that reabsorb urate in the renal proximal tubules (URAT1, GLUT9, OAT4 and OAT10) and secrete urate (ABCG2, OAT1, OAT3, NPT1, and NPT4) in the renal tubules and intestine, is a major cause of hyperuricemia, along with variations in the genes encoding these proteins. The first-line therapeutic drugs used to lower serum uric acid levels include XOD inhibitors that limit uric acid biosynthesis and uricosurics that decrease urate reabsorption in the renal proximal tubules and increase urate excretion into the urine and intestine via urate transporters. However, long-term use of high doses of these drugs induces acute kidney disease, chronic kidney disease and liver toxicity. Therefore, there is an urgent need for new nephroprotective drugs with improved safety profiles and tolerance. The current systematic review summarizes the characteristics of major urate transporters, the mechanisms underlying the pathogenesis of hyperuricemia, and the regulation of uric acid biosynthesis and transport. Most importantly, this review highlights the potential mechanisms of action of some naturally occurring bioactive compounds with antihyperuricemic and nephroprotective potential isolated from various medicinal plants.

Uric acid and blood pressure in NHANES dated from 2009 to 2018: A cross-sectional research

BACKGROUND AND AIM

This study aimed to explore the association between uric acid (UA) and blood pressure (BP), included systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP).

METHODS AND RESULTS

A cross-sectional study with 22,478 individuals aged from 12 to 80 years (11,443 males and 11,035 females) from the National Health and Nutrition Examination Survey (NHANES) was performed. Multiple linear regression analysis was applied to explore the relationship between UA and BP, Stratified analysis and interaction were performed based on gender, race, age, body mass index (BMI), and alcohol consumption. Significantly positively associations were presented in SBP(β, 0.84 [95% CI, 0.67, 1.00]), DBP(β, 0.23 [95% CI, 0.11, 0.36]), and MAP (β, 0.43 [95% CI, 0.31, 0.55]). The associations were much more stronger between UA and SBP in females (β, 1.04 [95% CI, 0.78, 1.30], p for interaction 0.0003), black group (β, 1.17 [95% CI, 0.77, 1.56], p for interaction 0.0296), age (≥45) group (β, 1.03 [95% CI, 0.68, 1.39], p for interaction <0.0001) and drinking group (β, 0.98 [95% CI, 0.75, 1.21], p for interaction <0.0001). The significant interactions were found between UA and DBP in gender and alcohol consumption (all p for interaction <0.05). In terms of MAP, the significant interactions were found in race, age, and alcohol consumption (all p for interaction <0.05).

CONCLUSIONS

A significantly positively association was found between UA and BP, including SBP, DBP, and MAP.

GCKR and GCK polymorphisms are associated with increased risk of end-stage kidney disease in Chinese patients with type 2 diabetes: The Hong Kong Diabetes Register (1995-2019)

AIMS

Glucokinase (GCK) and glucokinase regulatory protein (GKRP) regulate glucose and lipid metabolism. We investigated the associations of GCKR and GCK polymorphisms with kidney outcomes.

METHODS

Analyses were performed in a prospective cohort who were enrolled in the Hong Kong Diabetes Register between 1995 and 2017. The associations of GCKR rs1260326 and GCK rs1799884 polymorphisms with incident end-stage kidney disease (ESKD), albuminuria and rapid eGFR decline were analysed by Cox regression or logistic regression with adjustment.

RESULTS

6072 patients (baseline mean age 57.4 years; median diabetes duration 6.0 years; 54.5 % female) were included, with a median follow-up of 15.5 years. The GCKR rs1260326 [HR (95 %CI) 1.23 (1.05-1.44) for CT; HR 1.23 (1.02-1.48) for TT] and GCK rs1799884 T alleles [HR 1.73 (1.24-2.40) for TT] were independently associated with increased risk of ESKD versus their respective CC genotypes. GCKR rs1260326 T allele was also associated with albuminuria [OR 1.18 (1.05-1.33) for CT; OR 1.34 (1.16-1.55) for TT] and rapid eGFR decline.

CONCLUSIONS

In Chinese patients with type 2 diabetes, T allele carriers of GCKR rs1260326 and GCK rs1799884 were at high risk for ESKD. These genetic markers may be used to identify high risk patients for early intensive management for renoprotection.

Association between Serum Uric Acid and Hypertension in a Large Cross-Section Study in a Chinese Population

Background: The association of serum uric acid (SUA) with hypertension has been well established in Caucasian populations. However, its association with hypertension in Chinese remained to be clarified. Methods: Consecutive patients, homogeneous in Chinese Han ethnicity, aged ≥18 years, abstracted from the database, admitted from 1 January 2010 to 31 December 2013, were included for potential analysis. The patients were grouped according to the presence or absence of hypertension. Unconditional logistic regression was performed to estimate the association between SUA and hypertension. Its possible interactions with risk factors on hypertension were also explored. Results: A total of 9587 patients were finally analyzed in the current study, where 5692 were with hypertension and 3895 were without hypertension. Per 100 μmol/L higher SUA concentration was associated with multivariable-adjusted odds ratios (95% CI) of 1.25 (1.08−1.22) in males, 1.10 (1.01−1.20) in females, and 1.19 (1.13−1.24) in total. On a categorical scale, when compared with the first quintile, the multivariable-adjusted odds ratios (95% CI) were 1.40 (1.20−1.64) for the 2nd quintile, 1.48 (1.27−1.74) for the 3rd quintile, 1.55 (1.32−1.82) for the 4th quintile, and 1.92 (1.63−2.26) for the 5th quintile, with a p for trend < 0.01. Conclusions: SUA is associated with hypertension in a dose-response manner among the Chinese hospitalized population. Management of SUA could help to the prevention and control of hypertension.

Research Progress on the Relationship between Dietary Patterns and Hyperuricemia

As the final metabolite of purine metabolism, uric acid is critically associated with human health. The serum uric acid level is regulated by diet and the metabolic capacity of the human body. The impaired control of uric acid metabolism and excretion is associated with the increased level of serum uric acid, which ultimately results in hyperuricemia. Hyperuricemia is the "fourth-highest" after hypertension, hyperglycemia, and hyperlipidemia. With progress made in the relationship between diet and hyperuricemia, different dietary patterns and lifestyles have been discussed, such as exercise, the amount intake of meat, seafood, supplements with omega-3 fatty acids, sugar-sweetened soft drinks and energy drinks, and lower-fat-containing foods as well as drinking beer, wine, and spirits in the present article. This study demonstrated that a lower risk of hyperuricemia is substantially correlated with higher baseline adherence to MeDiet, and plant polyphenols can combat hyperuricemia by blocking xanthine oxidase.

Trends in the Contribution of Genetic Susceptibility Loci to Hyperuricemia and Gout and Associated Novel Mechanisms

Hyperuricemia and gout are complex diseases mediated by genetic, epigenetic, and environmental exposure interactions. The incidence and medical burden of gout, an inflammatory arthritis caused by hyperuricemia, increase every year, significantly increasing the disease burden. Genetic factors play an essential role in the development of hyperuricemia and gout. Currently, the search on disease-associated genetic variants through large-scale genome-wide scans has primarily improved our understanding of this disease. However, most genome-wide association studies (GWASs) still focus on the basic level, whereas the biological mechanisms underlying the association between genetic variants and the disease are still far from well understood. Therefore, we summarized the latest hyperuricemia- and gout-associated genetic loci identified in the Global Biobank Meta-analysis Initiative (GBMI) and elucidated the comprehensive potential molecular mechanisms underlying the effects of these gene variants in hyperuricemia and gout based on genetic perspectives, in terms of mechanisms affecting uric acid excretion and reabsorption, lipid metabolism, glucose metabolism, and nod-like receptor pyrin domain 3 (NLRP3) inflammasome and inflammatory pathways. Finally, we summarized the potential effect of genetic variants on disease prognosis and drug efficacy. In conclusion, we expect that this summary will increase our understanding of the pathogenesis of hyperuricemia and gout, provide a theoretical basis for the innovative development of new clinical treatment options, and enhance the capabilities of precision medicine for hyperuricemia and gout treatment.

Sex differences in the human metabolome

BACKGROUND

The sexual dimorphism represents one of the triggers of the metabolic disparities between the organisms, advising about wild implications in research or diagnostics contexts. Despite the mounting recognition of the importance of sex consideration in the biomedical fields, the identification of male- and female-specific metabolic signatures has not been achieved.

MAIN BODY

This review pointed the focus on the metabolic differences related to the sex, evidenced by metabolomics studies performed on healthy populations, with the leading aim of understanding how the sex influences the baseline metabolome. The main shared signatures and the apparent dissimilarities between males and females were extracted and highlighted from the metabolome of the most commonly analyzed biological fluids, such as serum, plasma, and urine. Furthermore, the influence of age and the significant interactions between sex and age have been taken into account.

CONCLUSIONS

The recognition of sex patterns in human metabolomics has been defined in diverse biofluids. The detection of sex- and age-related differences in the metabolome of healthy individuals are helpful for translational applications from the bench to the bedside to set targeted diagnostic and prevention approaches in the context of personalized medicine.

An association study of ABCG2 rs2231142 on the concentrations of allopurinol and its metabolites

ABCG2 is a gene that codes for the human breast cancer resistance protein (BCRP). It is established that rs2231142 G>T, a single nucleotide polymorphism of the ABCG2 gene, is associated with gout and poor response to allopurinol, a uric acid‐lowering agent used to treat this condition. It has also been suggested that oxypurinol, the primary active metabolite of allopurinol, is a substrate of the BCRP. We thus hypothesized that carrying the rs2231142 variant would be associated with decreased oxypurinol concentrations, which would explain the lower reduction in uric acid. We performed a cross‐sectional study to investigate the association between the ABCG2 rs2231142 variant and oxypurinol, allopurinol, and allopurinol riboside concentrations in 459 participants from the Montreal Heart Institute Hospital Cohort. Age, sex, weight, use of diuretics, and estimated glomerular filtration rate were all significantly associated with oxypurinol plasma concentration. No association was found between rs2231142 and oxypurinol, allopurinol and allopurinol riboside plasma concentrations. Rs2231142 was not significantly associated with daily allopurinol dose in the overall population, but an association was observed in men, with T carriers receiving higher doses. Our results do not support a major role of ABCG2 in the pharmacokinetics of allopurinol or its metabolites. The underlying mechanism of the association between rs2231142 and allopurinol efficacy requires further investigation.

Examining an Association of Single Nucleotide Polymorphisms with Hyperuricemia in Chinese Flight Attendants

Background

Both genetic and environmental factors strongly affect serum uric acid (SUA) concentrations. The incidence of hyperuricemia tends to be younger in the Chinese population. In particular, we have found a high prevalence of hyperuricemia among Chinese flight attendants, aged from 20 to 40, in our survey. This study aims to evaluate whether there is an association between gene polymorphisms and hyperuricemia among Chinese flight attendants.

Methods

A total of 532 flight attendants with high and normal serum uric acid levels were recruited. Allele-specific polymerase chain reaction (AS-PCR) was performed using blood samples of enrolled subjects.

Results

Previous studies have reported single nucleotide polymorphisms (SNPs) that are tightly associated with uric acid levels. Among them, six SNPs that are strongly associated with SUA or gout in Asians, for instance ABCG2 (rs2231142, rs72552713 and rs2231137), GCKR (rs780094), SLC2A9 (rs1014290) and SLC17A1 (rs1183201), were selected for AS-PCR analyses. We found that SNPs such as ABCG2 rs2231142, GCKR rs780094 and SLC2A9 rs1014290 are strongly associated with hyperuricemia in male flight attendants, and SLC2A9 rs1014290 among female flight attendants.

Conclusion

Our study provides evidences of an association between SNPs and hyperuricemia in the Chinese flight attendants, and highlights the significance of improving diagnostics and prevention of disease development in uric acid metabolism disorders and gout using these SNPs.

Molecular Quantitative Trait Locus Mapping in Human Complex Diseases

Mapping quantitative trait loci (QTLs) for molecular traits from chromatin to metabolites (i.e., xQTLs) provides insight into the locations and effect modes of genetic variants that influence these molecular phenotypes and the propagation of functional consequences of each variant. xQTL studies indirectly interrogate the functional landscape of the molecular basis of complex diseases, including the impact of non-coding regulatory variants, the tissue specificity of regulatory elements, and their contribution to disease by integrating with genome-wide association studies (GWAS). We summarize a variety of molecular xQTL studies in human tissues and cells. In addition, using the Alzheimer's Disease Sequencing Project (ADSP) as an example, we describe the ADSP xQTL project, a collaborative effort across the ADSP Functional Genomics Consortium (ADSP-FGC). The project's ultimate goal is a reference map of Alzheimer's-related QTLs using existing datasets from multiple omics layers to help us study the consequences of genetic variants identified in the ADSP. xQTL studies enable the identification of the causal genes and pathways in GWAS loci, which will likely aid in the discovery of novel biomarkers and therapeutic targets for complex diseases. © 2022 Wiley Periodicals LLC.

Sex-specific effect of serum urate levels on coronary heart disease and myocardial infarction prevention: A Mendelian randomization study

BACKGROUND AND AIMS

Observational studies have examined serum urate levels in relation to coronary heart disease (CHD) and myocardial infarction (MI). Whether these associations are causal remains controversial, due to confounding factors and reverse causality. We aim to investigate the causality of these associations using Mendelian randomization method.

METHODS AND RESULTS

Instrumental variables were obtained from the largest genome-wide association studies of serum urate (457,690 individuals) to date. Summary statistics were from CARDIoGRAMplusC4D consortium (60,801 CHD cases; 43,676 MI cases), FinnGen (21,012 CHD cases; 12,801 MI cases), UK Biobank (10,157 CHD cases; 7018 MI cases), and Biobank Japan (29,319 CHD cases). Inverse-variance weighted method was applied as the main results. Other statistical methods and reverse MR analysis were conducted in the supplementary analyses. Elevated genetically determined serum urate levels were associated with increased risks of CHD and MI. The association pattern remained for the datasets in FinnGen, the combined results of three independent data sources (CHD: odds ratio (OR), 1.10; 95%CI, 1.06-1.15; p = 4.2 × 10^-6; MI: OR, 1.12; 95%CI, 1.07-1.18; p = 2.7 × 10^-6), and East Asian population. Interestingly, sex-specific subgroup analyses revealed that these associations kept in men only, but not among women in individuals of European ancestry. No consistent evidence was found for the causal effect of CHD or MI on serum urate levels.

CONCLUSION

We provide consistent evidence for the causal effect of genetically predicted serum urate levels on CHD and MI, but not the reverse effect. Urate-lowering therapy may be of cardiovascular benefit in the prevention of CHD and MI, especially for men.

The individual and global impact of copy-number variants on complex human traits

The impact of copy-number variations (CNVs) on complex human traits remains understudied. We called CNVs in 331,522 UK Biobank participants and performed genome-wide association studies (GWASs) between the copy number of CNV-proxy probes and 57 continuous traits, revealing 131 signals spanning 47 phenotypes. Our analysis recapitulated well-known associations (e.g., 1q21 and height), revealed the pleiotropy of recurrent CNVs (e.g., 26 and 16 traits for 16p11.2-BP4-BP5 and 22q11.21, respectively), and suggested gene functionalities (e.g., MARF1 in female reproduction). Forty-eight CNV signals (38%) overlapped with single-nucleotide polymorphism (SNP)-GWASs signals for the same trait. For instance, deletion of PDZK1, which encodes a urate transporter scaffold protein, decreased serum urate levels, while deletion of RHD, which encodes the Rhesus blood group D antigen, associated with hematological traits. Other signals overlapped Mendelian disorder regions, suggesting variable expressivity and broad impact of these loci, as illustrated by signals mapping to Rotor syndrome (SLCO1B1/3), renal cysts and diabetes syndrome (HNF1B), or Charcot-Marie-Tooth (PMP22) loci. Total CNV burden negatively impacted 35 traits, leading to increased adiposity, liver/kidney damage, and decreased intelligence and physical capacity. Thirty traits remained burden associated after correcting for CNV-GWAS signals, pointing to a polygenic CNV architecture. The burden negatively correlated with socio-economic indicators, parental lifespan, and age (survivorship proxy), suggesting a contribution to decreased longevity. Together, our results showcase how studying CNVs can expand biological insights, emphasizing the critical role of this mutational class in shaping human traits and arguing in favor of a continuum between Mendelian and complex diseases.