Genome-wide association analyses identify 18 new loci associated with serum urate concentrations

Metabolic crosstalk and therapeutic interplay between diabetes and hyperuricemia

Hyperuricemia and diabetes mellitus (DM) are prevalent metabolic disorders with high comorbidity, imposing a substantial global public health burden. Their coexistence is not merely additive but synergistic, exacerbating metabolic dysregulation through mechanisms such as insulin resistance and β-cell apoptosis, ultimately establishing a vicious cycle. Both disorders induce acute and chronic damage to vital organs, particularly the cardiovascular, renal systems. Hyperuricemia aggravates diabetic complications, notably diabetic cardiomyopathy, nephropathy and retinopathy via oxidative stress, inflammation, and metabolic dysregulation.Current urate-lowering therapies (ULTs), such as xanthine oxidase inhibitors and urate transporter 1 (URAT1, also known as SLC22A12) antagonists, demonstrate potential benefits in ameliorating diabetic complications but face challenges including safety concerns and dose adjustments. Similarly, several glucose-lowering drugs also exhibit the benefits of improving hyperuricemia. This review summarizes the metabolic crosstalk and therapeutic interplay between hyperuricemia and DM, examines the pathogenic role of uric acid in diabetic complications, and discusses the benefits and challenges of existing ULTs and glucose-lowering drugs in disrupting this cycle of metabolic dysregulation and concurrent organ damage. We hope our findings deepen the comprehension of the intricate metabolic crosstalk between glucose and urate homeostasis, providing novel therapeutic insights for patients with comorbid DM and hyperuricemia.

The association between genetic polymorphisms in GCKR and gout: A systematic review and meta-analysis

BACKGROUND

As far as we know, there are no studies summarizing single nucleotide polymorphism (SNP) in the GCKR gene associated with gout, and the association of SNP in the GCKR gene with gout is controversial.

METHODS

Studies were obtained from PubMed, Embase, Web of Science, and Cochrane Library, last searched on February 20, 2024. We reviewed the reported SNP loci of the GCKR gene associated with gout. A meta-analysis was performed to examine the association of SNPs with gout and to investigate whether this association was consistent across populations.

RESULTS

A total of 11 studies were included. 4 GCKR gene SNP loci associated with gout were identified, namely rs780094, rs1260326, rs6547694, rs780093. Meta-analysis showed that SNPs of the GCKR gene were significantly associated with gout (odds ratio [OR]: 1.27; 95% confidence intervals [CI]: 1.21-1.34). Rs780094 (OR: 1.38; 95%CI:1.31-1.44), rs1260326 (OR: 1.26; 95%CI: 1.13-1.39), and rs780093 (OR: 1.17; 95%CI: 1.06-1.27) were all significantly associated with gout. There were no statistically significant differences in effect sizes for rs780094, rs1260326, and rs780093 across populations.

CONCLUSIONS

We identified 4 SNPs of the GCKR gene associated with gout and demonstrated that all these SNPs are important genetic factors for gout risk.

Gene-environment interaction modifies the association between hyperinsulinemia and serum urate levels through SLC22A12

BACKGROUNDHyperinsulinemia and insulin resistance often accompany elevated serum urate levels (hyperuricemia), a highly heritable condition that triggers gout; however, the underlying mechanisms are unclear.METHODSWe evaluated the association between the index of hyperinsulinemia and the fractional excretion of urate (FEUA) in 162 outpatients. The underlying mechanisms were investigated through single-cell data analysis and kinase screening combined with cell culture experiments. In 377,358 participants of the UK Biobank (UKBB), we analyzed serum urate, hyperinsulinemia, and salt intake. We also examined gene-environment interactions using single nucleotide variants in SLC22A12, which encodes urate transporter 1 (URAT1).RESULTSThe index of hyperinsulinemia was inversely associated with FEUA independently of other covariates. Mechanistically, URAT1 cell-surface abundance and urate transport activity were regulated by URAT1-Thr408 phosphorylation, which was stimulated by hyperinsulinemia via AKT. Kinase screening and single-cell data analysis revealed that serum and glucocorticoid-regulated kinase 1 (SGK1), induced by high salt, activated the same pathway, increasing URAT1. Arg405 was essential for these kinases to phosphorylate URAT1-Thr408. In UKBB participants, hyperinsulinemia and high salt intake were independently associated with increased serum urate levels. We found that SLC22A12 expression quantitative trait locus (eQTL) rs475688 synergistically enhanced the positive association between serum urate and hyperinsulinemia.CONCLUSIONURAT1 mediates the association between hyperinsulinemia and hyperuricemia. Our data provide evidence for the role of gene-environment interactions in determining serum urate levels, paving the way for personalized management of hyperuricemia.FUNDINGACRO Research Grants of Teikyo University; Japan Society for the Promotion of Science; the Japanese Society of Gout and Uric & Nucleic Acids; Fuji Yakuhin; Nanken-Kyoten; Medical Research Center Initiative for High Depth Omics.

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.

Causal relationship between serum urate and asthma: a Mendelian randomization study

BACKGROUND

Previous studies have suggested that elevated urate levels may increase the risk of asthma; however, the nature of this association remains debated. To clarify this uncertainty, we conducted a Mendelian randomization (MR) study to investigate the potential causal relationship.

METHODS

Summary statistics for urate were sourced from the Global Urate Genetics Consortium (GUGC), and those for asthma were obtained from the FinnGen database. Genetic variants strongly associated with urate were selected as instrumental variables (IVs). Univariable and multivariable MR analyses were conducted to investigate the causal relationship between urate and asthma. Subsequently, network MR analyses were performed to reveal the mediating role of urate in the relationship between body mass index (BMI) and asthma.

RESULTS

The univariable MR analysis showed that urate was associated with an increased risk of asthma (IVW OR = 1.13, 95%CI = 1.04-1.23, p = 0.004). This causal relationship remained consistent in multivariable MR analyses, even after adjusting for potential confounders, including smoking initiation, cigarettes per day, alcohol intake frequency, BMI, allergic rhinitis, and gastroesophageal reflux disease (GERD). Furthermore, network MR analyses demonstrated that the proportion of causal effect between BMI and asthma mediated by urate was 18.05% (95%CI = 6.23%-29.88%).

CONCLUSION

Our study confirms that serum urate is associated with an increased risk of asthma, suggesting its potential as a target for both prevention and treatment. Additionally, our findings indicate that urate partially mediates the relationship between BMI and asthma, emphasizing its role in the mechanism underlying BMI-induced asthma.

The mediating roles of anthropo-metabolic biomarkers on the association between beverage consumption and breast cancer risk

BACKGROUND

Breast cancer (BC) is the most common malignancy in women, yet the role of beverage consumption in BC risk remains unclear. Additionally, the contribution of anthropo-metabolic biomarkers as mediators is unknown, limiting the development of effective prevention strategies.

METHODS

This study included 13,567 participants from the Guangzhou Biobank Cohort Study (GBCS), where beverage consumption was assessed at baseline using a food frequency questionnaire. BC cases were identified through cancer registry linkage over a mean follow-up of 14.8 years. Mendelian randomization (MR) analyses were performed to evaluate the causal effects of beverage consumption on BC risk, with a two-step MR approach used to estimate mediation effects.

RESULTS

During follow-up, 243 BC cases were identified. Weekly consumption of ≥ 1 portion of sugar sweetened beverages (SSB), versus < 1 portion, was significantly associated with a higher risk of BC (hazard ratio [HR] 1.58, 95% confidence interval [CI] 1.12-2.23). This association was partly mediated by body mass index (proportion mediated [PM] 4.2%, 95% CI 0.9-17.1%) and uric acid (PM 18.8%, 95% CI 1.5-77.5%). Weekly consumption of > 6 portions of dairy-based milk was associated with a non-significantly higher BC risk (HR 1.41, 95% CI 0.99-2.03), while 3-6 portions of soy milk were associated with a lower BC risk (HR 0.31, 95% CI 0.10-0.98). No significant associations were found for pure fruit juice, coffee, tea, or alcoholic drinks. MR analyses supported the detrimental effect of SSB on BC risk, with high-density lipoprotein cholesterol, polyunsaturated fatty acids to total fatty acids (TFAs) ratio, and omega-6 fatty acids to TFAs ratio mediating 2.44%, 2.73%, and 3.53% of the association, respectively.

CONCLUSION

This study suggested that SSB consumption was a risk factor for BC and identified key anthropo-metabolic biomarkers mediating this relationship. Reducing SSB consumption and addressing associated metabolic pathways may offer effective strategies for BC prevention.

Gout drives metabolic dysfunction-associated steatotic liver disease through gut microbiota and inflammatory mediators

This study explores the relationship between gout and metabolic dysfunction-associated steatotic liver disease (MASLD), two metabolic conditions linked to worsening health outcomes. While hyperuricemia's association with MASLD is established, the specific connection between gout and MASLD remains less explored. Using data from the UK Biobank, the study employs COX proportional hazard models, multi-state survival analysis, and Mendelian randomization to assess the independent and mutual risks of gout and MASLD. Findings indicate a mutual risk increase: male gout patients, those younger than 60, and those with high BMI are particularly susceptible to MASLD, while female MASLD patients are at heightened risk for gout. Shared risk factors for both conditions include high BMI, hypertension, diabetes, and hyperuricemia. The study further identifies a bidirectional causal link, with gout leading to MASLD, mediated by gut microbiota Ruminococcaceae and proteins like IL-2 and GDF11, implicating specific metabolic pathways. The findings highlight a clinical and mechanistic correlation, emphasizing the need for targeted interventions to address these overlapping metabolic pathways in future treatments.

Serum uric acid levels and intracerebral hemorrhage: A two-sample Mendelian randomization study

OBJECTIVE

Previous observational studies have generated controversy regarding the correlation between serum uric acid (UA) levels and intracerebral hemorrhage (ICH), with the causal relationship remaining uncertain. To assess the potential causal relationship between serum UA levels and ICH, two-sample Mendelian randomization analysis was applied.

METHODS

Single-nucleotide polymorphisms (SNPs) closely associated with serum UA were retrieved from the genome-wide association study (GWAS) database, including 580,505 individuals of European descent. A total of 27 and 251 SNPs were chosen as instrumental variables. Summary data for ICH included 1935 cases and 471,578 controls. Two-sample MR analyses, including inverse-variance weighted (IVW), MR-Egger, weighted median, and weighted mode methods, were employed to assess the potential causal relationship between serum UA levels and ICH, with odds ratios (ORs) as effect estimates. Heterogeneity was evaluated using Cochran's Q test, and sensitivity analyses were conducted using the leave-one-out method.

RESULTS

The IVW analysis revealed that a 1 mg/dL increase in serum UA was associated with a 16.5 % higher risk of ICH (OR 1.165, 95 % CI 1.01-1.34, P = 0.034), while a 1 quantile increase in serum UA was associated with a 25.9 % higher risk (OR 1.259, 95 % CI 1.091-1.46, P = 0.002). Cochran's Q test showed no evidence of heterogeneity. No horizontal pleiotropy was detected. The sensitivity analysis using the leave-one-out method supported the robustness and reliability of our results.

CONCLUSION

The study reveals that elevated serum UA levels are causally linked to ICH, suggesting the potential applicability of serum UA as a biomarker for the occurrence of ICH.

Comprehensive Analysis of Uric Acid and Myasthenia Gravis: IGF1R as a Protective Factor and Potential Therapeutic Target

BACKGROUND

Previous studies have suggested that oxidative stress can significantly damage acetylcholine receptors (AChRs), which are implicated in the pathogenesis of myasthenia gravis (MG). Uric acid (UA), a scavenger of peroxynitrite and a natural antioxidant, plays a crucial role in eliminating free radicals in the bloodstream. However, the relationship between UA and MG, as well as the underlying mechanisms, remains insufficiently explored.

METHODS

A meta-analysis was conducted to evaluate the clinical correlation between UA and MG. Subsequently, Mendelian randomization (MR) and bioinformatics analyses were employed to identify the key protein IGF1R. Public datasets, such as TCGA and GEO, along with patient data from our clinical center, were used for a comprehensive analysis of the relationship between IGF1R and UA in MG patients. Additionally, virtual screening and molecular docking were performed to identify small molecules that target IGF1R as potential therapeutic agents for MG.

RESULTS

The meta-analysis revealed a significant association between low UA levels and MG (OR -48.46 [95% CI -63.26, -33.65], p < 0.00001). The two-sample MR analysis indicated a genetic relationship between UA and MG (p = 0.024; p = 0.036). The FUMA analysis and enrichment analysis identified IGF1R as a key protein likely involved in this relationship. Using the thymoma dataset from the TCGA database, we analyzed IGF1R expression in the MG and non-MG groups and found that IGF1R expression was lower in MG patients and was associated with a poor prognosis (p < 0.05). Single-cell RNA-seq data from the GEO database further supported the association between low IGF1R expression and MG, as well as the occurrence of crisis (p < 0.05). Additionally, data from MG patients treated at our center showed that IGF1R expression correlated with UA levels and that higher IGF1R expression was associated with milder clinical phenotypes (ocular phenotypes). Through a virtual screen and molecular docking of small molecules in the DrugBank database, we identified several potential small-molecule drugs that may target IGF1R to treat MG.

CONCLUSIONS

Our study revealed an association between low UA levels and MG and subsequently showed that low IGF1R expression is associated with the onset, severity, and poor prognosis of MG. We also explored the molecular mechanisms underlying the protective role of IGF1R in MG and identified potential drugs for treating MG.

Associations of the ALDH2 rs671 polymorphism and alcohol intake with early-onset gout in a Chinese male cohort

OBJECTIVE

Gout in young people is increasingly common across the world, including in China. This study aimed to identify clinical and genetic associations with early-onset gout in Chinese men.

METHODS

One thousand two hundred and one Chinese men with gout were included. Early-onset gout was defined as the first presentation of gout at <30years. Twenty single nucleotide polymorphisms (SNPs) identified as gout-risk loci or associated with serum urate (SU) levels in East Asian populations were genotyped. Logistic regression was used to evaluate the association of SNPs and clinical factors with early-onset gout.

RESULTS

Four hundred and thirty-three (36.1%) participants were identified as having early-onset gout. These patients had higher SU levels and were more likely to experience gout flares than those with later-onset gout. The ALDH2 rs671 GG genotype was associated with a lower risk of early-onset gout. Compared to those with GG genotype who never drank alcohol before gout onset, individuals with AA or AG genotypes who drank alcohol before gout onset had a higher likelihood of early-onset gout. Additionally, alcohol intake significantly increased the likelihood of gout flares in early-onset gout patients. Moreover, body mass index, sugar-sweetened beverage intake, family history of gout and renal urate underexcretion were associated with early-onset gout.

CONCLUSIONS

The ALDH2 rs671 GG genotype was significantly associated with a lower risk of early-onset gout, while individuals with the AA or AG genotype who consumed alcohol were more susceptible. These findings indicate that alcohol intake is a potentially modifiable risk factor for early-onset gout in genetically susceptible individuals.

Conducting genetic epidemiology research on hyperuricaemia and gout in an indigenous community in Guam - a feasibility study

BACKGROUND

Gout, the most common inflammatory arthritis disease, and hyperuricaemia onset are influenced by environmental and genetic factors. We sought to investigate these factors in an Indigenous community in Guam.

METHODS

In this feasibility study, the University of Guam led the qualitative inquiry with the native community, training (pre-screening of participants, data collection methods, and biospecimen handling), study implementation (outreach and recruitment, data collection, and DNA extraction and quantification), and qualitative and epidemiologic data analyses. Recruitment targets were based on demographic representation in current census data. The University of Otago collaborated on ethics guidance, working with Indigenous communities, and led the genetic sequencing and genetic data analysis. Participants were recruited in Guam from Fall 2019 to Spring 2022.

RESULTS

Of the 359 participants, most self-identified as Native CHamorus (61.6%) followed by Other Micronesians (22.0%), and Filipinos (15.6%). The prevalence of metabolic conditions from highest to lowest were obesity (55.6%), hyperuricaemia (36.0%), hypertension (27.8%), gout (23.0%), diabetes (14.9%), cardiovascular disease (8.4%), kidney disease (7.3%), and liver disease (3.4%). There was variation in the prevalence of metabolic conditions among the major ethnic groups in this study.

CONCLUSIONS

We estimated the prevalence of metabolic conditions, especially gout and hyperuricaemia, and found variation among ethnic groups, all while obtaining the Indigenous community's feedback on the genetic study and building gout research capacity. The results of ongoing genetic sequencing will be used to understand molecular causes of gout in Guam.

Effects of Baicalin on Gout Based on Network Pharmacology, Molecular Docking, and in vitro Experiments

Purpose

Baicalin is a flavonoid of Scutellaria baicalensis Georgi. It possesses antipyretic, analgesic, and anti-inflammatory effects. It has great potential to treat gout. A network pharmacology approach, molecular docking and experimental validation were applied to investigate the pharmacological mechanisms of baicalin in treating gout.

Methods

The potential targets of baicalin were retrieved from the TCMSP, PharmMapper, STITCH, and Swiss Target Prediction databases. The gout-related targets were retrieved from the DrugBank, TTD, and Genecards databases. Then, the potential targets and signaling pathways were acquired via protein-protein interaction (PPI), as well as the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Subsequently, the key targets were selected to dock with baicalin based on molecular docking. Finally, in vitro experiments were conducted to further validate the predictions.

Results

A total of 318 potential targets of baicalin and 752 gout-related targets were screened. TNF, VEGFA, MMP9, PTGS2, and TLR4 might be the hub therapeutic target genes. The TLR4/NF-κB signaling pathway might be the foremost pathway in baicalin against gout. Moreover, molecular docking showed that baicalin combined well with TNF, VEGFA, MMP9, COX-2, and TLR4, respectively. The results of cell experiments suggested that baicalin could reduce the levels of inflammatory cytokines by inhibiting the TLR4/NF-κB signaling pathway in MSU-stimulated THP-1 cells and regulate the expression of these hub targets.

Conclusion

These results revealed that baicalin possesses "multitarget, multipathway, multilevel" regulatory effects. From a therapeutic standpoint, baicalin may be a promising anti-inflammatory agent for alleviating gout.

Spatiotemporal landscape of kidney in a mouse model of hyperuricemia at single-cell level

Serum uric acid is an end-product of purine metabolism. Uric acid concentrations in excess of the physiological range may lead to diseases such as gout, cardiovascular disease, and kidney injury. The kidney includes a variety of cell types with specialized functions such as fluid and electrolyte homeostasis, detoxification, and endocrine functions. Two-thirds of uric acid is excreted through kidney, however, the exploration of markers and new therapeutic targets in renal tissue of hyperuricemia is still lacking. Single-cell and spatial omics techniques represent major milestones in life sciences. The combined measurement of the physical structure and molecular characteristics of tissues facilitates the exploration of the pathophysiological processes underlying disease development and the discovery of possible therapeutic targets. Here, the spatiotemporal atlas of hyperuricemic nephropathy was investigated using single-cell RNA sequencing, spatial transcriptomics, spatial proteomics, and spatial metabolomics in a urate oxidase knockout mouse model. Several emerging targets and pathways especially ribosome and metabolism related to uric acid excretion were discovered and will be investigated further in studies on lowering uric acid.

Association between serum iron status and gout: results from the NHANES and Mendelian randomization study

Aims. Previous observational studies have provided inconsistent evidence for the association between serum iron status and the risk of gout. Moreover, it remains uncertain whether the observed association is causal or due to confounding or reverse causality. This research aimed to investigate the association of serum iron status indicators with the risk of gout and to further examine the causal relationship by the Mendelian randomization (MR) method. Methods. We first conducted a cross-sectional study from the National Health and Nutrition Examination Survey 2017-2018, including a total of 4635 participants. The association of serum iron status indicators with gout risk was evaluated using a multivariable logistic regression model. Furthermore, a two-sample MR study using genetic data from large-scale genome-wide association studies of serum iron status indicators (246 139 individuals) and gout (discovery: 13 179 cases and 75 0634 controls; replication: 5292 cases and 368 788 controls; 2115 cases and 67 259 controls) was conducted to infer causality. Inverse-variance-weighting (IVW) was applied as the main method of MR analysis. A series of sensitivity analyses were used to evaluate the robustness of their relationship. Results. In the cross-sectional study, there was no significant relationship between serum iron status indicators and gout risk. However, IVW results showed that genetically predicted serum iron and transferrin saturation (TSAT) were significantly associated with the increased risk of gout in the discovery analysis [odds ratio (OR): 1.21; 95% confidence interval (CI): 1.10-1.32; P = 9.80 × 10-5 for serum iron and OR: 1.16; 95% CI: 1.08-1.25; P = 7.14 × 10-5 for TSAT]. The replication analysis provided similar results compared with the discovery analysis. Conclusion. Our study provides support for potential causal associations between serum iron and the altered risk of gout. Further investigations are warranted to elucidate the biological processes through which iron influences susceptibility to gout.

Novel Genetic Loci in Early-Onset Gout Derived From Whole-Genome Sequencing of an Adolescent Gout Cohort

OBJECTIVE

Mechanisms underlying the adolescent-onset and early-onset gout are unclear. This study aimed to discover variants associated with early-onset gout.

METHODS

We conducted whole-genome sequencing in a discovery adolescent-onset gout cohort of 905 individuals (gout onset 12 to 19 years) to discover common and low-frequency single-nucleotide variants (SNVs) associated with gout. Candidate common SNVs were genotyped in an early-onset gout cohort of 2,834 individuals (gout onset ≤30 years old), and meta-analysis was performed with the discovery and replication cohorts to identify loci associated with early-onset gout. Transcriptome and epigenomic analyses, quantitative real-time polymerase chain reaction and RNA sequencing in human peripheral blood leukocytes, and knock-down experiments in human THP-1 macrophage cells investigated the regulation and function of candidate gene RCOR1.

RESULTS

In addition to ABCG2, a urate transporter previously linked to pediatric-onset and early-onset gout, we identified two novel loci (Pmeta < 5.0 × 10-8): rs12887440 (RCOR1) and rs35213808 (FSTL5-MIR4454). Additionally, we found associations at ABCG2 and SLC22A12 that were driven by low-frequency SNVs. SNVs in RCOR1 were linked to elevated blood leukocyte messenger RNA levels. THP-1 macrophage culture studies revealed the potential of decreased RCOR1 to suppress gouty inflammation.

CONCLUSION

This is the first comprehensive genetic characterization of adolescent-onset gout. The identified risk loci of early-onset gout mediate inflammatory responsiveness to crystals that could mediate gouty arthritis. This study will contribute to risk prediction and therapeutic interventions to prevent adolescent-onset gout.

Serum Urate and Atrial Fibrillation: A Bidirectional Mendelian Randomization Study

BACKGROUND

Observational studies indicate that serum urate level is associated with atrial fibrillation (AF). However, whether this association is causal remains controversial, due to confounding factors and reverse causality. We aim to evaluate the causal relationship of genetically predicted serum urate level with AF.

METHODS

A bidirectional Mendelian randomization (MR) study was performed. Instrumental variables were obtained from the Global Urate Genetics Consortium (110347 individuals). We obtained summary statistics of AF from two genome-wide association studies (GWAS) data sets for AF. Inverse-variance-weighted method was applied to obtain MR estimates and other statistical methods were conducted in the sensitivity analyses. The reverse MR analysis was performed to evaluate the effect of AF on serum urate levels.

RESULTS

Genetically determined serum urate level was not associated with AF in two studies (OR, 1.03; 95% CI, 0.95-1.11; p = 0.47); (OR, 1.06; 95% CI, 0.99-1.12; p = 0.09). The main results kept robust in the most sensitivity analyses. Multivariable MR analyses suggested that the association pattern did not change, after adjusting for body mass index (BMI), HbA1c: hemoglobin A1c (HbA1c), hypertension, low-density lipoprotein cholesterol (LDL-C) and coronary heart disease. No causal effect of AF on serum urate levels was found in two studies (OR, 1.02; 95% CI, 0.98-1.05; p = 0.30); (OR, 1.00; 95% CI, 0.98-1.03; p = 0.95).

CONCLUSIONS

Our MR study supports no bidirectional causal effect of serum urate levels and AF. This implies that treatments aimed at lowering uric acid may not reduce the risk of AF.

Pediatrics hyperuricemia in clinical practice: A retrospective analysis in 1753 children and adolescents with hyperuricemia

OBJECTIVES

Serum levels of uric acid (S-UA) are influenced by the interaction of genetic and environmental factors; detailed studies of hyperuricemia in children are rare. This retrospective study aimed to analyze the causes, risk factors, and therapeutic approaches associated with the development of hyperuricemia in childhood.

METHODS

In a single-center study, serum uric acid levels were analyzed in 33,900 samples from 13,890 children and adolescents<19 years (6760 girls and 7130 boys) obtained between 2013 and 2023. Hyperuricemia was defined as S-UA>370μmol/L (6.22mg/dL) in girls and>420μmol/L (7.06mg/dL) in boys; mild hyperuricemia was defined as 370-420μmol/L in boys<13 years.

RESULTS

In the analyzed group, hyperuricemia was found in 1753 patients (12.6%), including 586 girls and 864 boys; mild hyperuricemia was found in 303 boys<13 years. The most common associated conditions were obesity with body mass index>95th percentile (27.8% of girls, 26.3% of boys) and chronic kidney disease (18.6% of boys, 11.4% of girls). Hyperuricemia was also relatively common in children with connective tissue disorders (10.6%) or different inherited metabolic disorders (10.7%). Transitory hyperuricemia was found in 19.1% of girls and 10.1% of boys with acute gastroenteritis. Urate-lowering therapy was used in 73 children and adolescents with severe hyperuricemia (S-UA 556±107μmol/L, fraction excretion of UA 3.27±1.98%). Eight treated children had chronic kidney disease, nine were extremely obese, one had combined antiepileptic therapy, and 55 had inherited metabolic diseases, including 26 children with disorders of purine metabolism. The initial daily dose of allopurinol (50-100mg) normalized the S-UA (350±80μmol/L) in a majority of children, except for extremely obese adolescents (weight 98-149kg) where the dose had to be increased to 200-300mg.

CONCLUSIONS

Asymptomatic hyperuricemia is a relatively common biochemical finding in pediatric clinical practice. The etiology of hyperuricemia should be carefully analyzed, and the value of individualized hyperuricemia management and the eventual benefits of urate-lowering therapy in children must be carefully considered.

Downregulation of type I interferon signalling pathway by urate in primary human PBMCs

Type I interferons (IFN1s) mediate innate responses to microbial stimuli and regulate interleukin (IL)-1 and IL-1 receptor antagonist (Ra) production in human cells. This study explores interferon-stimulated gene (ISG) alterations in the transcriptome of patients with gout and stimulated human primary cells in vitro in relation to serum urate concentrations. Peripheral blood mononuclear cells (PBMCs) and monocytes of patients with gout were primed in vitro with soluble urate, followed by lipopolysaccharide (LPS) stimulation. Separately, PBMCs were stimulated with various toll-like receptor (TLR) ligands. RNA sequencing and IL-1Ra cytokine measurement were performed. STAT1 phosphorylation was assessed in urate-treated monocytes. Cytokine responses to IFN-β were evaluated in PBMCs cultured with or without urate and restimulated with LPS and monosodium urate (MSU) crystals. Transcriptomics revealed suppressed IFN-related signalling pathways in urate-exposed PBMCs or monocytes which was supported by diminishment of phosphorylated STAT1. The stimulation of PBMCs with IFN-β did not modify the urate-induced inflammation. Interestingly, in vivo, serum urate concentrations were inversely correlated to in vitro ISG expression upon stimulations with TLR ligands. These findings support a deficient IFN1 signalling in the presence of elevated serum urate concentrations, which could translate to increased susceptibility to infections.

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.

Exploring genetic links between blood metabolites and gout susceptibility

BACKGROUND

Gout, a prevalent form of inflammatory arthritis, has a complex etiology where the causal relationship between metabolites and the disease remains underexplored. This study aims to elucidate the impact of genetically determined blood metabolites on gout.

METHODS

Employing a two-sample bidirectional Mendelian randomization analysis, we examined the association between 1400 blood metabolites and gout. Causal associations were determined using the inverse variance weighted (IVW) method with false discovery rate (FDR) correction. Sensitivity analyses encompassed weighted models, MR-Egger, weighted median, and MR-PRESSO approaches. MR-pleiotropy and Cochran's Q statistic were utilized to evaluate potential heterogeneity and pleiotropy. Additionally, metabolic pathway analyses were conducted to pinpoint relevant pathways.

RESULTS

Of the initial 4 serum metabolites identified, 3 known metabolites-hexanoylglutamine levels, mannose content, and the phosphate to mannose ratio-were found to be causally associated with gout, along with 55 serum metabolites identified as potential predictors of gout (PIVW < 0.05). Furthermore, we discovered 3 metabolic pathways implicated in gouty attacks.

CONCLUSION

Our findings, derived from Mendelian randomization, indicate that the identified metabolites and pathways may serve as biomarkers for clinical screening and prevention of gout. Additionally, they offer novel insights into the mechanisms of the disease and potential drug targets. Key points • Conducted a comprehensive Mendelian randomization study involving 1400 blood metabolites to explore their genetic impact on gout development and progression • Identified three key metabolites-hexanoylglutamine, mannose, and the phosphate-to-mannose ratio-with causal associations to gout, highlighting their potential use as biomarkers for early detection and risk stratification • Discovered 55 additional serum metabolites as potential predictors of gout, offering new insights into the pathophysiology of the disease and identifying high-risk individuals • Revealed three novel metabolic pathways involved in gout attacks, providing new therapeutic targets for precision medicine in gout treatment.

The metabolic sensor AMPK: Twelve enzymes in one

BACKGROUND

AMP-activated protein kinase (AMPK) is an evolutionarily conserved regulator of energy metabolism. AMPK is sensitive to acute perturbations to cellular energy status and leverages fundamental bioenergetic pathways to maintain cellular homeostasis. AMPK is a heterotrimer comprised of αβγ-subunits that in humans are encoded by seven individual genes (isoforms α1, α2, β1, β2, γ1, γ2 and γ3), permitting formation of at least 12 different complexes with personalised biochemical fingerprints and tissue expression patterns. While the canonical activation mechanisms of AMPK are well-defined, delineation of subtle, as well as substantial, differences in the regulation of heterogenous AMPK complexes remain poorly defined.

SCOPE OF REVIEW

Here, taking advantage of multidisciplinary findings, we dissect the many aspects of isoform-specific AMPK function and links to health and disease. These include, but are not limited to, allosteric activation by adenine nucleotides and small molecules, co-translational myristoylation and post-translational modifications (particularly phosphorylation), governance of subcellular localisation, and control of transcriptional networks. Finally, we delve into current debate over whether AMPK can form novel protein complexes (e.g., dimers lacking the α-subunit), altogether highlighting opportunities for future and impactful research.

MAJOR CONCLUSIONS

Baseline activity of α1-AMPK is higher than its α2 counterpart and is more sensitive to synergistic allosteric activation by metabolites and small molecules. α2 complexes however, show a greater response to energy stress (i.e., AMP production) and appear to be better substrates for LKB1 and mTORC1 upstream. These differences may explain to some extent why in certain cancers α1 is a tumour promoter and α2 a suppressor. β1-AMPK activity is toggled by a 'myristoyl-switch' mechanism that likely precedes a series of signalling events culminating in phosphorylation by ULK1 and sensitisation to small molecules or endogenous ligands like fatty acids. β2-AMPK, not entirely beholden to this myristoyl-switch, has a greater propensity to infiltrate the nucleus, which we suspect contributes to its oncogenicity in some cancers. Last, the unique N-terminal extensions of the γ2 and γ3 isoforms are major regulatory domains of AMPK. mTORC1 may directly phosphorylate this region in γ2, although whether this is inhibitory, especially in disease states, is unclear. Conversely, γ3 complexes might be preferentially regulated by mTORC1 in response to physical exercise.

Triglyceride-glucose index and its additive interaction with ABCG2/SLC2A9 polygenic risk score on hyperuricemia in middle age and older adults: findings from the DLCC and BHMC study

OBJECTIVE

We aim to investigate the joint effect of triglyceride-glucose (TyG) index and polygenic risk scores (PRS) of urate transporter genes ABCG2 and SLC2A9 on hyperuricemia.

METHODS

Baseline data from two prospective population-based cohort studies, including 30,453 individuals aged 50 years or older, were used to analyze the association between TyG index and hyperuricemia. A case-control study was then designed from the cohorts to investigate the interaction between genetic predisposition and TyG index on hyperuricemia among 595 matched pairs. PRS was constructed using 14 single nucleotide polymorphisms located in the ABCG2 and SLCA29 genes.

RESULTS

In both sexes, higher TyG index levels were correlated with elevated serum urate (SUA) levels (p values in both sexes < 0.001). In men, per unit increase of TyG was associated with a 1.44-fold (95% confidence interval [CI]: 1.35-1.55) higher risk of hyperuricemia after adjusted for covariates. In women, this estimate was 1.69 (1.51-1.89). Demonstrated by the restrict cubic spline model, TyG index was both linearly and non-linearly associated with elevated SUA (both p values < 0.001). Association between TyG index and hyperuricemia was stronger among people with higher genetic risk, and vice versa. Compared to people with TyG < 9 and PRS < 2, the odds ratios (ORs) (95% CIs) for hyperuricemia in the TyG <9 but PRS ≥2, TyG ≥9 but PRS < 2, TyG ≥9 and PRS ≥2 groups were 3.30 (1.53-7.14), 3.16 (1.23-8.11) and 7.55 (2.76-20.65), respectively. Additive interaction was also significant, with 57.5% (30.5%-84.4%) of the excess risk attributable to the additive gene-TyG index interaction.

CONCLUSIONS

The impact of genetic predisposition on hyperuricemia was significantly greater among individuals with a higher TyG index. Over 50% of the increased risk can be attributed to the interaction, indicating a crucial synergy between genetic factors and TyG index when estimating hyperuricemia risk.

Gout-associated SNP at the IL1RN-IL1F10 region is associated with altered cytokine production in PBMCs of patients with gout and controls

OBJECTIVES

Gout is caused by the response of the innate immune system to monosodium urate (MSU) crystals. A recent gout GWAS identified a signal of genetic association at a locus encompassing IL1RN-IL1F10. Colocalisation analysis using Genotype Tissue Expression Database (GTEx) eQTL data showed that the signal overlaps with genetic control of IL1RN/IL1F10 gene expression. We assess the functional implications of IL1RN rs9973741, the lead gout-associated variant.

METHODS

We conducted functional validation of IL1RN rs9973741 in patients with gout and controls. The transcription level of IL1RN/IL1F10 was investigated in unstimulated or MSU-crystal co-stimulated PBMCs. Ex vivo functional assays were performed in PBMCs stimulated with C16 + MSU crystals or LPS for 24 h. Cytokine levels were assessed by ELISA.

RESULTS

In unstimulated PBMCs, no association of IL1RN rs9973741 (gout risk allele G) to IL1RN expression was observed while IL-1F10 was hindered by low expression at both transcriptional and protein levels. However, G allele carriers showed lower IL1RN expression in PBMCs stimulated with C16/MSU crystal and lower concentrations of circulating IL-1Ra in both controls and gout patients. PBMCs depicted less spontaneous IL-1Ra release in GG homozygous controls and lower IL-1Ra production in response to C16 + MSU crystal costimulation in patients with gout. The G allele was associated with elevated IL-1β cytokine production in response to C16 + MSU crystal stimulation in controls.

CONCLUSIONS

The gout risk allele G associates with lower circulating IL-1Ra, lower IL-1Ra production in PBMC assays and elevated IL-1β production in PBMCs challenged with C16 + MSU crystals but not in unchallenged cells. Our data indicate that the genetic signal that associates with gout at IL1RN-IL1F10 region functions to alter expression of IL-1Ra when stimulated by MSU crystals.

Phyllanthi Fructus ameliorates hyperuricemia and kidney injure via inhibiting uric acid synthesis, modulating urate transporters, and alleviating inflammation

Phyllanthi Fructus, known as Yuganzi (YGZ), is a unique medicine and food homologous fruit with both medicinal and nutritional properties. Its historical use in treating hyperuricemia (HUA) and gout is well-documented. However, the precise therapeutic effects and potential molecular mechanisms remain unclear. In this study, an experimental rat modelling by a high-fat/high-sugar diet and potassium oxonate/adenine oral administration was used to evaluate the pharmacodynamic effects of YGZ. Network pharmacology, molecular docking and molecular dynamics simulation were utilized to elucidate the potential mechanisms. Supplementation with YGZ effectively ameliorated HUA by inhibiting xanthine oxidase activity, and enhancing uric acid excretion through up-regulating of OAT1 and ABCG2, while down-regulating of URAT1. Furthermore, YGZ supplementation enhanced superoxide dismutase activity, reduced malondialdehyde content, and inhibited the secretion of IL1B, IL6, TNFα, ICAM1, VCAM1, TGFβ1, and NF-κB protein expression. Network pharmacology analysis indicated that YGZ influences 138 targets, modulating the disease network via lipid and atherosclerosis, insulin resistance, HIF-1, TNF, IL-17, TLRS, and NF-κB signaling pathways. Molecular docking analysis suggested that organic acids (e.g. ellagic acid, gallic acid) and flavonoids (e.g. quercetin, delphinidin, luteolin, epigallocatechin gallate) exhibited superior binding abilities to key targets (e.g. XDH, ABCG2, URAT1, OAT1, IRS1, PTGS2, TLR4). Noteworthy, molecular dynamics simulations confirmed that epigallocatechin gallate binds to URAT1 with the greatest stability. These results provide substantial evidence for the therapeutic efficacy of YGZ and establish a theoretical foundation for the development of natural products in treating hyperuricemia.

Gout Risk After Total Knee Arthroplasty: A Propensity-score-matched Cohort Study

BACKGROUND/AIM

Gout, characterized by acute inflammatory symptoms and monosodium urate crystal deposits in joints, is prevalent among males and the elderly. Total knee arthroplasty (TKA) is a common treatment for knee osteoarthritis (OA), but its impact on the risk of developing gout is unclear. This study examined the risk of gout in patients undergoing TKA.

PATIENTS AND METHODS

Utilizing the TriNetX research network, a retrospective cohort study was conducted on OA patients without prior gout. The TKA cohort was compared to a non-TKA control group using propensity score matching to balance covariates. The primary outcome was the incidence of gout over a five-year follow-up period.

RESULTS

The study included 38,834 matched pairs of TKA and non-TKA patients. TKA patients had a 15.6% higher risk of developing gout (HR=1.156; 95%CI=1.042-1.284) compared to controls. Sensitivity analyses confirmed the increased risk across various models and follow-up durations.

CONCLUSION

TKA is associated with a higher risk of developing gout, particularly in females and older adults. Clinicians should monitor and manage gout risk in TKA patients, emphasizing preventive measures and early intervention. Further research is needed to understand the underlying mechanisms and improve patient care post-TKA.

MR Corge: sensitivity analysis of Mendelian randomization based on the core gene hypothesis for polygenic exposures

SUMMARY

Mendelian randomization is being utilized to assess causal effects of polygenic exposures, where many genetic instruments are subject to horizontal pleiotropy. Existing methods for detecting and correcting for horizontal pleiotropy have important assumptions that may not be fulfilled. Built upon the core gene hypothesis, we developed MR Corge for performing sensitivity analysis of Mendelian randomization. MR Corge identifies a small number of putative core instruments that are more likely to affect genes with a direct biological role in an exposure and obtains causal effect estimates based on these instruments, thereby reducing the risk of horizontal pleiotropy. Using positive and negative controls, we demonstrated that MR Corge estimates aligned with established biomedical knowledge and the results of randomized controlled trials. MR Corge may be widely applied to investigate polygenic exposure-outcome relationships.

AVAILABILITY AND IMPLEMENTATION

An open-sourced R package is available at https://github.com/zhwm/MRCorge.

A genome-wide association analysis reveals new pathogenic pathways in gout

Gout is a chronic disease that is caused by an innate immune response to deposited monosodium urate crystals in the setting of hyperuricemia. Here, we provide insights into the molecular mechanism of the poorly understood inflammatory component of gout from a genome-wide association study (GWAS) of 2.6 million people, including 120,295 people with prevalent gout. We detected 377 loci and 410 genetically independent signals (149 previously unreported loci in urate and gout). An additional 65 loci with signals in urate (from a GWAS of 630,117 individuals) but not gout were identified. A prioritization scheme identified candidate genes in the inflammatory process of gout, including genes involved in epigenetic remodeling, cell osmolarity and regulation of NOD-like receptor protein 3 (NLRP3) inflammasome activity. Mendelian randomization analysis provided evidence for a causal role of clonal hematopoiesis of indeterminate potential in gout. Our study identifies candidate genes and molecular processes in the inflammatory pathogenesis of gout suitable for follow-up studies.

NUMB dysfunction defines a novel mechanism underlying hyperuricemia and gout

Defective renal excretion and increased production of uric acid engender hyperuricemia that predisposes to gout. However, molecular mechanisms underlying defective uric acid excretion remain largely unknown. Here, we report a rare genetic variant of gout-unprecedented NUMB gene within a hereditary human gout family, which was identified by an unbiased genome-wide sequencing approach. This dysfunctional missense variant within the conserved region of the NUMB gene (NUMBR630H) underwent intracellular redistribution and degradation through an autophagy-dependent mechanism. Mechanistically, we identified the uric acid transporter, ATP Binding Cassette Subfamily G Member 2 (ABCG2), as a novel NUMB-binding protein through its intracellular YxNxxF motif. In polarized renal tubular epithelial cells (RTECs), NUMB promoted ABCG2 trafficking towards the apical plasma membrane. Genetic loss-of-function of NUMB resulted in redistribution of ABCG2 in the basolateral domain and ultimately defective excretion of uric acid. To recapitulate the clinical situation in human gout patients, we generated a NUMBR630H knock-in mouse strain, which showed marked increases of serum urate and decreased uric acid excretion. The NUMBR630H knock-in mice exhibited clinically relevant hyperuricemia. In summary, we have uncovered a novel NUMB-mediated mechanism of uric acid excretion and a functional missense variant of NUMB in humans, which causes hyperuricemia and gout.

Causal relationship between uric acid and stroke: a two-sample mendelian randomization study

Many previous observational studies have disputed whether there is a link between uric acid and stroke. And the causal relationship between uric acid and stroke is unclear. To determine whether there is a causal relationship between uric acid and stroke by using mendelian randomization (MR). Uric acid dataset was obtained from Anna Kottgen et al, with a sample size of 110,347 people, including 2450,548 single nucleotide polymorphisms (SNPs). Stroke pooled data from Malik R et al, publicly available in MEGASTROKE genome-wide association study, included meta-analysis data from 40,585 stroke patients and 406,111 control patients, totaling 8211,693 SNPs. The summary data of genome-wide association study of uric acid and stroke were collected from publicly available online databases. Inverse variance weighting was used to determine the causal relationship between uric acid and stroke. MR-Egger and weighted median model were used for supplementary analysis. Results were then analyzed for heterogeneity, pleiotropy, and sensitivity to ensure no statistical pleiotropy and to reduce bias. A total of 27 SNPs were included in this study after the disequilibrium instrumental variables were excluded. Check the PhenoScanner database for SNPs associated with confounders. In the end, a total of 8 SNPs were excluded. Two SNPs were excluded because the correction direction was the same. Since the F statistic is >10, rs10761587 and rs1825043 are excluded. Finally, 15 SNPs were selected as uric acid instrumental variables. Inverse variance weighting-fixed effect model suggested that there was no causal relationship between uric acid and stroke (odds ratio = 1.004, 95% confidence interval = 0.940, 1.072). MR-Egger and weighted median model also showed the same result. In addition, the results of this study were robust without heterogeneity and pleiotropy. This MR study suggests no support of a causal relationship between uric acid and stroke.

The association between triglyceride glucose index and gout: a cross-sectional analysis based on NHANES 2007-2018

BACKGROUND

The triglyceride glucose (TyG) index, defined as Ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2], provides insights into overall metabolic status. However, the association between the TyG index and gout has not been investigated. Therefore, this study explored the correlation between the TyG index and gout.

METHODS

Using data from the National Health and Nutrition Examination Survey, which was conducted from 2007 to 2018, this study investigated the relationship between the TyG index and gout. Demographic data and potential risk factors were analyzed and compared using t tests for continuous data and chi-square tests for categorical data. Logistic regression and subgroup analysis were performed to examine the association between the TyG index and gout.

RESULTS

A total of 14,924 participants were enrolled, among whom 726 (4.86%) were diagnosed with gout. Without controlling for any covariates, a significant positive correlation was observed between an elevated TyG index and increased risk of gout, with an odds ratio (OR) of 2.07 and a 95% confidence interval (CI) ranging from 1.76 to 2.43. After full adjustment, this association remained statistically significant, with an adjusted OR of 1.43 and a 95% CI from 1.14 to 1.80. Subgroup analyses revealed significant interactions, particularly for females (OR = 2.55; 95% CI: 2.00-3.26), individuals with no military service history (OR = 2.15; 95% CI: 1.66-2.43), and those without diabetes (OR = 2.00; 95% CI: 1.64-2.43).

CONCLUSION

A positive correlation was observed between the TyG index and gout. Consequently, further large-scale prospective studies are warranted for a comprehensive analysis of the role of the TyG index in gout.

Association of cardiovascular disease and urate levels with aortic aneurysm: a bilateral mendelian randomization study

The aim of this study is to investigate the potential causal relationships between coronary artery disease (CAD), myocardial infarction (MI), urate levels, and aortic aneurysm (AA), abdominal aortic aneurysm (AAA), thoracic aortic aneurysm(TAA), aortic dissection (AD) in individuals of European ancestry. To examine the potential causal relationships between CAD, MI, and urate levels with AA, AAA, TAA, AD, respectively, we performed a two-sample Mendelian randomization (MR) analysis. Genetic instruments that reached genome-wide significance (p < 5 × 10 - 8) for risk factors were obtained from genome-wide association studies(GWASs) conducted on individuals of European origin. On the other hand, genetic instruments of AA, AAA, TAA or AD were chosen from the FinnGen cohort. The primary analysis employed the inverse-variance weighted MR method, while sensitivity analyses were conducted using MR-Egger, weighted median MR, MR pleiotropy residual sum and outlier, and Phenoscanner searching. In addition, we performed the MR-Egger intercept analysis to identify potential pleiotropy and utilized Cochran's Q statistics to evaluate heterogeneity. Additionally, we conducted bidirectional Mendelian randomization experiments to mitigate the potential influence of reverse causation. According to the results of our study, there were statistically significant higher risks for AA in relation to CAD/MI(odds ratio (OR) with 95% confidence interval (CI): 1.309 (1.150-1.490), and 1.255 (1.147-1.373). Similarly, there were statistically significant higher risks for AAA in relation to CAD and MI (OR with 95% CI: 1.383 (1.189-1.609), and 1.352 (1.178-1.552). The sensitivity analysis demonstrated that the causative effects of CAD/MI, and AA /AAA, were robust. A positive causal link was observed between CAD/MI, and AA/AAA. Nevertheless, no causal link was found between CAD, MI, urate levels, and TAA .

Cardiovascular risk according to genetic predisposition to gout, lifestyle and metabolic health across prospective European and Korean cohorts

OBJECTIVE

Recent studies have reported that gout is associated with a risk of cardiovascular disease (CVD) later in life. However, the predictive value of genetic predisposition to gout combined with lifestyle habits for CVD risk remains unclear. This study aimed to examine the association between genetic predisposition to gout and lifestyle habits and the risk of developing CVD in two diverse prospective cohorts from different ancestries.

METHODS

A total of 224 689 participants of European descent from the UK Biobank and 50 364 participants of East Asian descent from the Korean Genome and Epidemiology Study were included. The genetic risk for gout was assessed using a polygenic risk score (PRS) derived from a meta-genome-wide association study (n=444 533). The incident CVD risk was evaluated according to genetic risk, lifestyle and metabolic syndrome (MetS).

RESULTS

Individuals at high genetic risk for gout had a higher risk of incident CVD than those with low genetic risk across ancestry. Notably, a reduction in CVD risk by up to 62% (HR 0.38; 95% CI 0.31 to 0.46; p <0.001) was observed in individuals at both low and high genetic risk for gout when they maintained ideal MetS and favourable lifestyle habits.

CONCLUSIONS

Our findings indicate that a higher genetic risk of gout is significantly associated with an increased risk of CVD. Moreover, adherence to a favourable lifestyle can significantly reduce CVD risk, particularly in individuals with high genetic risk. These results underscore the potential of PRS-based risk assessment to improve clinical outcomes through tailored preventative strategies.

Uric Acid Levels and Cardiovascular and Cerebrovascular Diseases: A Mendelian Randomization Study

INTRODUCTION

The relationship between uric acid (UA) levels and cardiovascular and cerebrovascular diseases (CCVD) is controversial. A two-sample Mendelian randomization (MR) study was conducted to explore the causal effects of UA levels on CCVD.

METHODS

Genetic variants strongly associated with UA levels were selected as instrumental variables from the Genome-Wide Association Study (GWAS) dataset. The GWAS data, sourced from the Global Urate Genetics Consortium (GUGC), comprised a sample size of 110,347 individuals. The selected CCVD outcomes included stroke, coronary artery disease (CAD), as well as atrial fibrillation and flutter. The primary analytical approach employed the inverse-variance weighted (IVW) method, supplemented by MR-Egger and weighted median as complementary methods. Sensitivity analysis was performed to test heterogeneity and pleiotropy.

RESULTS

The MR analysis results indicated a causal association between UA levels and stroke (odds ratio [OR]: 1.002; 95% confidence interval [CI]: 1.000-1.003; p = 0.036), CAD (OR: 1.118; 95% CI: 1.044-1.197; p = 0.001), as well as atrial fibrillation and flutter (OR: 1.141; 95% CI: 1.037-1.256; p = 0.007). The results of MR-Egger and weighted median methods confirmed the direction of the IVW results, enhancing the robustness of the findings. No significant anomalies were detected in the sensitivity analysis.

CONCLUSION

The MR study suggests that UA levels exert causal effects on stroke, CAD, as well as atrial fibrillation and flutter.

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.

Association of the ABCG2 rs2231142 variant with the Framingham Cardiovascular Disease Risk score in the Taiwanese population

Background

Serum uric acid (SUA) is an important predictor of cardiovascular events and mortality. The ABCG2 rs2231142 variant (TT genotype) is associated with hyperuricemia (HUA), but the relationship between ABCG2 gene polymorphisms and coronary artery disease (CAD) risk is poorly elucidated. We investigated the association between ABCG2 rs2231142 genetic variants and the Framingham Risk Score for Cardiovascular Disease (FRS-CVD) in a Taiwanese population.

Methods

This cross-sectional study enrolled 139,508 Taiwanese participants aged 30-70 years based on data from the Taiwan Biobank (TWB) database that was obtained from questionnaires, laboratory investigations, anthropometry, and Affymetrix TWB genome-wide single-nucleotide polymorphism (SNP) chip data analysis. The association between ABCG2 rs2231142 and FRS-CVD risk was evaluated using logistic regression analysis.

Results

Compared to those with the GG genotype, participants with the ABCG2 rs2231142 TT genotype had a significantly lower systolic blood pressure, smoking rate, body mass index, triglyceride level, waist circumference, waist-hip ratio, and body fat percentage, but had higher high-density lipoprotein cholesterol level. Despite the same FRS-CVD score, participants with TT genotypes had higher SUA. Even with the same SUA, TT carriers had a lower FRS-CVD than GT and GG carriers. Participants with the TT genotype had significantly lower CVD risk, particularly female participants with HUA and BMI <27 (OR: 0.760, 95 % CI: 0.587-0.985; p = 0.0381) group.

Conclusion

The ABCG2 rs2231142 TT genotype is associated with a lower FRS-CVD, particularly in non-obese hyperuricemic female individuals. The complicated interplay among genetic variations, metabolic profile, and CVD risk provides insights for precision health.

Association between serum iron status and the risk of five bone and joint-related diseases: a Mendelian randomization analysis

Background

According to reports, iron status has been associated with the risk of bone and joint-related diseases. However, the exact role of iron status in the development of these conditions remains uncertain.

Method

We obtained genetic data on iron status, specifically serum iron, ferritin, transferrin saturation (TSAT), and transferrin, as well as data on five common bone and joint-related diseases (osteoarthritis, osteoporosis, rheumatoid arthritis [RA], ankylosing spondylitis [AS], and gout) from independent genome-wide association studies involving individuals of European ancestry. Our primary approach for causal estimation utilized the inverse variance weighted (IVW) method. To ensure the reliability of our findings, we applied complementary sensitivity analysis and conducted reverse causal analysis.

Result

Using the IVW method, we revealed a positive causal relationship between ferritin levels and the risk of osteoarthritis (OR [95% CI], 1.0114 [1.0021-1.0207]). Besides, we identified a protective causal relationship between serum iron levels and TSAT levels in the risk of RA (OR [95% CI] values of serum iron and TSAT were 0.9987 [0.9973-0.9999] and 0.9977 [0.9966-0.9987], respectively). Furthermore, we found a positive causal relationship between serum iron levels and the risk of AS (OR [95% CI], 1.0015 [1.0005-1.0026]). Regarding gout, both serum iron and TSAT showed a positive causal relationship (OR [95% CI] values of 1.3357 [1.0915-1.6345] and 1.2316 [1.0666-1.4221] for serum iron and TSAT, respectively), while transferrin exhibited a protective causal relationship (OR [95% CI], 0.8563 [0.7802-0.9399]). Additionally, our reverse causal analysis revealed a negative correlation between RA and ferritin and TSAT levels (OR [95% CI] values of serum iron and TSAT were 0.0407 [0.0034-0.4814] and 0.0049 [0.0002-0.1454], respectively), along with a positive correlation with transferrin (OR [95% CI], 853.7592 [20.7108-35194.4325]). To ensure the validity of our findings, we replicated the results through sensitivity analysis during the validation process.

Conclusion

Our study demonstrated a significant correlation between iron status and bone and joint-related diseases.

Gout arthritis of the ankle successfully treated with arthroscopic debridement: A case report

INTRODUCTION

Gout is an inflammatory arthritis that causes acute pain due to the accumulation of uric acid crystals. Hyperuricemia primarily causes it, resulting in the deposition of monosodium urate crystals in and around joints. Gout can affect joints such as the metatarsophalangeal joint and the foot's talus bone. Treatment involves addressing hyperuricemia and managing symptoms with medications like febuxostat. Surgical treatment is crucial, especially in cases of chronic tophaceous gout or severe joint damage, including arthroscopic debridement, ankle arthrodesis, or total ankle arthroplasty.

CASE PRESENTATION

A 32-year-old male with a history of hyperuricemia experienced pain in his left ankle for a year. The ankle was swollen and prone to pain when he walked. Magnetic resonance imaging (MRI) tests revealed the thickening and irregular shape of the anterior talofibular ligament (ATFL), suggesting a rupture. The arthroscopic operation revealed a crystal deposit, leading to the diagnosis of gout arthritis and subsequent debridement for the patient. Following the surgery, the patient experienced minimal pain, an improved range of motion, and a significant improvement in swelling within a week. The patient was able to walk with minimal assistance and without aid.

DISCUSSION

Gout arthritis and ATFL injuries share common clinical features, including joint swelling, limited motion, and joint deformity. The presence of monosodium urate (MSU) crystals and inflammation in both conditions complicates diagnosis. Performing arthroscopic debridement surgery in gout arthritis presents challenges due to tophi and inflammation, as well as the risk of articular cartilage damage. Expertise is crucial for successful arthroscopic debridement, with patient selection, preoperative planning, and thorough removal of MSU crystals being key factors.

CONCLUSION

Thorough evaluation, patient selection, preoperative planning, joint identification, removal of MSU crystals, and comprehensive postoperative care are crucial for successful arthroscopic debridement for gout arthritis of the ankle.

Impact of hyperuricemia on CKD risk beyond genetic predisposition in a population-based cohort study

The bidirectional effect of hyperuricemia on chronic kidney disease (CKD) underscores the importance of hyperuricemia as a risk factor for CKD. We evaluated the effect of hyperuricemia on the presence and development of CKD after considering genetic background by calculating polygenic risk scores (PRSs). We employed genome-wide association study summary statistics-excluding the United Kingdom Biobank (UKB) datasets among published CKD Gen Consortium papers-to calculate the PRSs for CKD in white background subjects. To validate PRS performance, we divided the UKB into two datasets to validate and test the data. We used logistic regression analysis to evaluate the association between hyperuricemia and CKD, and performed Kaplan-Meier survival analysis exclusively for subjects with available follow-up data. In total, 438,253 clinical data and 4,307,940 single nucleotide polymorphisms from 459,155 samples were included. We observed a significant positive association between PRS and CKD and the presence and development of CKD. Hyperuricemia significantly increased CKD risk (adjusted odds ratio 1.55, 95% confidence interval 1.48-1.61). The impact of hyperuricemia on CKD was maintained irrespective of PRS range. In addition, negative interaction between hyperuricemia and PRS for CKD was found. Survival analysis indicates that the presence of hyperuricemia significantly increased the risk of CKD development. The PRS for CKD thoroughly reflects the risk of CKD development. Hyperuricemia is a significant indicator of CKD risk, even after incorporating the genetic risk score for CKD. Irrespective of genetic risk, patients with a prospective risk of developing CKD require uric acid monitoring and management.

The pathogenesis of gout: molecular insights from genetic, epigenomic and transcriptomic studies

The pathogenesis of gout involves a series of steps beginning with hyperuricaemia, followed by the deposition of monosodium urate crystal in articular structures and culminating in an innate immune response, mediated by the NLRP3 inflammasome, to the deposited crystals. Large genome-wide association studies (GWAS) of serum urate levels initially identified the genetic variants with the strongest effects, mapping mainly to genes that encode urate transporters in the kidney and gut. Other GWAS highlighted the importance of uncommon genetic variants. More recently, genetic and epigenetic genome-wide studies have revealed new pathways in the inflammatory process of gout, including genetic associations with epigenomic modifiers. Epigenome-wide association studies are also implicating epigenomic remodelling in gout, which perhaps regulates the responsiveness of the innate immune system to monosodium urate crystals. Notably, genes implicated in gout GWAS do not include those encoding components of the NLRP3 inflammasome itself, but instead include genes encoding molecules involved in its regulation. Knowledge of the molecular mechanisms underlying gout has advanced through the translation of genetic associations into specific molecular mechanisms. Notable examples include ABCG2, HNF4A, PDZK1, MAF and IL37. Current genetic studies are dominated by participants of European ancestry; however, studies focusing on other population groups are discovering informative population-specific variants associated with gout.

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.

Sex-specific epigenetic signatures of circulating urate and its increase after BCG vaccination

Background

Urate concentration and the physiological regulation of urate homeostasis exhibit clear sex differences. DNA methylation has been shown to explain a substantial proportion of serum urate variance, mediate the genetic effect on urate concentration, and co-regulate with cardiometabolic traits. However, whether urate concentration is associated with DNA methylation in a sex-dependent manner is unknown. Additionally, it is worth investigating if urate changes after perturbations, such as vaccination, are associated with DNA methylation in a sex-specific manner.

Methods

We investigated the association between DNA methylation and serum urate concentrations in a Dutch cohort of 325 healthy individuals. Urate concentration and DNA methylation were measured before and after Bacillus Calmette-Guérin (BCG) vaccination, used as a perturbation associated with increased gout flares. The association analysis included united, interaction, and sex-stratified analysis. Validation of the identified CpG sites was conducted using three independent cohorts.

Results

215 CpG sites were associated with serum urate in males, while 5 CpG sites were associated with serum urate in females, indicating sex-specific associations. Circulating urate concentrations significantly increased after BCG vaccination, and baseline DNA methylation was associated with differences in urate concentration before and after vaccination in a sex-specific manner. The CpG sites associated with urate concentration in males were enriched in neuro-protection pathways, whereas in females, the urate change-associated CpG sites were related to lipid and glucose metabolism.

Conclusion

Our study enhances the understanding of how epigenetic factors contribute to regulating serum urate levels in a sex-specific manner. These insights have significant implications for the diagnosis, prevention, and treatment of various urate-related diseases and highlight the importance of personalized and sex-specific approaches in medicine.

Shared genetic correlations between kidney diseases and sepsis

Background

Clinical studies have indicated a comorbidity between sepsis and kidney diseases. Individuals with specific mutations that predispose them to kidney conditions are also at an elevated risk for developing sepsis, and vice versa. This suggests a potential shared genetic etiology that has not been fully elucidated.

Methods

Summary statistics data on exposure and outcomes were obtained from genome-wide association meta-analysis studies. We utilized these data to assess genetic correlations, employing a pleiotropy analysis method under the composite null hypothesis to identify pleiotropic loci. After mapping the loci to their corresponding genes, we conducted pathway analysis using Generalized Gene-Set Analysis of GWAS Data (MAGMA). Additionally, we utilized MAGMA gene-test and eQTL information (whole blood tissue) for further determination of gene involvement. Further investigation involved stratified LD score regression, using diverse immune cell data, to study the enrichment of SNP heritability in kidney-related diseases and sepsis. Furthermore, we employed Mendelian Randomization (MR) analysis to investigate the causality between kidney diseases and sepsis.

Results

In our genetic correlation analysis, we identified significant correlations among BUN, creatinine, UACR, serum urate, kidney stones, and sepsis. The PLACO analysis method identified 24 pleiotropic loci, pinpointing a total of 28 nearby genes. MAGMA gene-set enrichment analysis revealed a total of 50 pathways, and tissue-specific analysis indicated significant enrichment of five pairs of pleiotropic results in kidney tissue. MAGMA gene test and eQTL information (whole blood tissue) identified 33 and 76 pleiotropic genes, respectively. Notably, genes PPP2R3A for BUN, VAMP8 for UACR, DOCK7 for creatinine, and HIBADH for kidney stones were identified as shared risk genes by all three methods. In a series of immune cell-type-specific enrichment analyses of pleiotropy, we identified a total of 37 immune cells. However, MR analysis did not reveal any causal relationships among them.

Conclusions

This study lays the groundwork for shared etiological factors between kidney and sepsis. The confirmed pleiotropic loci, shared pathogenic genes, and enriched pathways and immune cells have enhanced our understanding of the multifaceted relationships among these diseases. This provides insights for early disease intervention and effective treatment, paving the way for further research in this field.

Changes in alcohol intake and serum urate changes: longitudinal analyses of annual medical examination database

INTRODUCTION

Despite the established cross-sectional association between alcohol intake and serum urate (SU), its longitudinal association remains unknown. This study aimed to determine whether changes in alcohol intake have a clinically relevant association with SU change.

METHOD

We conducted retrospective analyses using systematically collected annual medical examination data from October 2012 to October 2022 in a Japanese preventive medicine centre. The exposure was changes in alcohol intake between two consecutive visits. The association of SU changes with alcohol intake changes was estimated by mixed-effect linear regression with adjustment for relevant covariates.

RESULTS

We analysed 63 486 participants (median age, 47.0 years; 55% women; 58.6% regular alcohol drinkers with a median of 1.4 drinks/day) with 370 572 visits. The median SU level was 5.3 mg/dL, and 506 (0.8%) participants had diagnoses of gout or hyperuricemia without medication use during the study period. Decreasing one daily alcohol intake had a clinically small association with SU changes (-0.019 (95% CI: -0.021 to -0.017) mg/dL). Beer had the largest association with SU (-0.036 (95% CI: -0.039 to -0.032) mg/dL for one beer decrease). Complete discontinuation of any alcohol from a mean of 0.8 drinks/day was associated with -0.056 mg/dL (95% CI: -0.068 to -0.043) decrease in SU; the association became larger in hyperuricemic participants (-0.110 mg/dL (95% CI: -0.154 to -0.066) for alcohol discontinuation from a mean of 1.0 drinks/day).

CONCLUSIONS

This study revealed changes in alcohol intake had small associations with SU change at the general Japanese population level. Complete discontinuation of alcohol in hyperuricemic participants had only modest improvement in SU.

Association between serum uric acid and colorectal cancer risk in European population: a two-sample Mendelian randomization study

Objectives

This study aimed to explore the potential causal associations between serum uric acid (SUA) and the risk of colorectal cancer, colon cancer and rectal cancer.

Methods

Twenty-six SUA-related single nucleotide polymorphisms which were identified by a large meta-analysis of genome-wide association studies (GWASs) were used as instrumental variables in the two-sample Mendelian randomization (MR) study. Meta-analyses were used to synthesize the results of multiple GWASs which were extracted from the MRC Integrative Epidemiology Unit GWAS database for each type of cancer. The inverse variance weighted (IVW) method was used as the primary MR method to analyze the association between SUA and colorectal cancer risk. Several sensitivity analyses were performed to test the robustness of results.

Results

The IVW method showed that there were no causal relationships between SUA and the risk of colorectal cancer [odds ratio (OR): 1.0015; 95% confidence interval (CI): 0.9975-1.0056] and colon cancer (OR: 1.0015; 95% CI: 0.9974-1.0055). The SUA levels were negative correlated with rectal cancer risk (OR: 0.9984; 95% CI: 0.9971-0.9998). The similar results were observed in both males (OR: 0.9987; 95% CI: 0.9975-0.9998) and females (OR: 0.9985; 95% CI: 0.9971-0.9999). The sensitivity analyses suggested no evidence of heterogeneity or horizontal pleiotropy. The leave-one-out analyses showed that one SNP (rs1471633) significantly drove the causal effect of SUA on rectal cancer risk. The MR-Egger regression and weighted median both showed that there were no causal relationships between SUA and the risk of colorectal cancer and its subtypes.

Conclusion

Overall, there was no linear causal association between SUA and the risk of colorectal cancer. However, further research is needed to investigate the role of higher SUA levels such as hyperuricemia or gout in the occurrence of colorectal cancer.

Trim46 knockout impaired neuronal architecture and caused hypoactive behavior in rats

BACKGROUND

Tripartite motif (TRIM46) is a relatively novel protein that belongs to tripartite motif family. TRIM46 organizes parallel microtubule arrays on the axons, which are important for neuronal polarity and axonal function. TRIM46 is highly expressed in the brain, but its biological function in adults has not yet been determined.

RESULTS

Trim46 knockout (KO) rat line was established using CRISPR/cas9. Trim46 KO rats had smaller hippocampus sizes, fewer neuronal dendritic arbors and dendritic spines, and shorter and more distant axon initial segment. Furthermore, the protein interaction between endogenous TRIM46 and FK506 binding protein 5 (FKBP5) in brain tissues was determined; Trim46 KO increased hippocampal FKBP5 protein levels and decreased hippocampal protein kinase B (Akt) phosphorylation, gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) and glutamate ionotropic receptor NMDA type subunit 1 (NMDAR1) protein levels. Trim46 KO rats exhibited hypoactive behavioral changes such as reduced spontaneous activity, social interaction, sucrose preference, impaired prepulse inhibition (PPI), and short-term reference memory.

CONCLUSIONS

These results demonstrate the significant impact of Trim46 KO on brain structure and behavioral function. This study revealed a novel potential association of TRIM46 with dendritic development and neuropsychiatric behavior, providing new insights into the role of TRIM46 in the brain.

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.

Systemic inflammatory cytokine profiles in patients with gout during flare, intercritical and treat-to-target phases: TNFSF14 as new biomarker

INTRODUCTION

Untreated gout is characterised by monosodium urate (MSU) crystal accumulation responsible for recurrent flares that are commonly separated by asymptomatic phases. Both phases are inflammatory conditions of variable intensity. Gout flares are self-limited inflammatory reactions involving multiple mediators. This study aimed to characterise the inflammatory profiles of gout at different phases.

METHODS

Using the Olink targeted proteomics, levels of 92 inflammation-related proteins were measured in plasma samples of a prospective gout population (GOUTROS), collected at gout flare (T1), the intercritical phase (T2) and after reaching the target serum urate level under urate-lowering therapy (T3). Results were validated in an independent cohort (OLT1177-05) with plasmas collected at T1 and T2. Ex vivo and in vitro experiments were performed to assess the inflammatory properties of new biomarkers.

RESULTS

In total, 21 inflammatory new biomarkers were differentially expressed during the three time-points of gout disease. The levels of four of these proteins (interleukin 6 (IL-6), colony-stimulating factor 1, vascular endothelial growth factor A and tumour necrosis factor superfamily 14 (TNFSF14)) were increased during gout flare in an independent cohort. IL-6 and TNFSF14 had the highest fold change in expression during T1 versus T2 or T3. TNFSF14 was produced at the inflamed joint and enhanced the inflammatory response induced by lipopolysaccharide and MSU crystal stimulation. Conversely, TNFSF14 blockade reduced the inflammatory response. Additionally, single nucleotide polymorphisms of TNFSF14 affected the ability of myeloid cells to produce inflammatory cytokines.

CONCLUSION

Gout flare involves multiple inflammatory mediators that may be used as potential therapeutic targets.

Causal associations of antioxidants with Alzheimer's disease and cognitive function: a Mendelian randomisation study

BACKGROUND

Circulating antioxidants are associated with a lower risk of Alzheimer's disease (AD) in observational studies, suggesting potential target areas for intervention. However, whether the associations are causal remains unclear. Here, we studied the causality between antioxidants and AD or cognitive function using two-sample Mendelian randomisation (MR).

METHODS

Single nucleotide polymorphisms strongly (p<5×10-8) associated with antioxidants (vitamin A, vitamin C, zinc, selenium, β-carotene and urate) and outcomes (AD, cognitive performance and reaction time) were obtained from the largest and most recent genome-wide association studies (GWAS). MR inverse variance weighting (IVW) and MR pleiotropy residual sum and outlier test (MR-PRESSO) were used for data analysis.

RESULTS

Higher genetically determined selenium level was associated with 5% higher risk of AD (OR 1.047, 95% CI 1.005 to 1.091, p=0.028) using IVW. Higher genetically determined urate level was associated with worse cognitive performance (β=-0.026, 95% CI -0.044 to -0.008, p=0.005) using MR-PRESSO. No association between the other antioxidants and AD, cognitive performance and reaction time was found. Similar results were found in the sensitivity analyses.

CONCLUSION

Our results suggest that lifelong exposure to higher selenium may be associated with a higher risk of AD, and higher urate levels could be associated with worse cognitive performance. Further analyses using larger GWAS of antioxidants are warranted to confirm these observations. Our results suggest that caution is needed in the interpretation of traditional observational evidence on the neuroprotective effects of antioxidants.

Mendelian randomization reveals the causal association between gout and hearing impairment in older adults

With the global aging trend escalating, the holistic well-being of the elderly has become a paramount concern within public health. Traditional observational studies often struggle with confounding factors and establishing causality, leaving the relationship between age-related hearing loss (ARHL) and gout largely unexplored. Employing bidirectional two-sample Mendelian randomization (MR) analysis, this investigation elucidated the genetic underpinnings associated with age-related hearing impairment, gout, and urate levels within the IEU Open-GWAS database, thereby uncovering potential causal connections that underlie the intricate interplay between gout, serum urate concentrations, and auditory decline in the geriatric demographic. In the forward MR phase, a cohort of 30 single nucleotide polymorphisms was leveraged to dissect the causal dynamics between ARHL and both gout and urate concentrations. Conversely, in the reverse MR phase, gout and urate levels were posited as the exposome to delineate their impact on hearing acuity, employing an array of models for rigorous validation and sensitivity scrutiny. In the forward MR analysis, a statistically significant correlation was discerned between ARHL and gout (P = .003, odds ratio = 1.01, 95% confidence interval: 1.00-1.02), alongside a notable association with serum urate levels (P = .031, odds ratio = 1.39, 95% confidence interval: 1.03-1.88), intimating that ARHL could potentially influence the incidence of gout and urate concentrations. Conversely, the reverse MR investigation revealed that neither gout nor serum urate levels exerted significant impact on auditory degradation (P > .05), insinuating that these factors might not predominantly contribute to hearing loss. Sensitivity analyses concurred with this inference. This study enriches the comprehension of geriatric health intricacies and unveils that ARHL potentially influences gout and serum urate concentrations. This suggests that monitoring ARHL may play a crucial role in the early identification and management of gout and hyperuricemia, potentially contributing to a comprehensive approach to improving geriatric health outcomes.