Replication of Gout/Urate Concentrations GWAS Susceptibility Loci Associated with Gout in a Han Chinese Population

Anti-inflammatory Properties of Tongfeng Li'an Granules in an Acute Gouty Arthritis Rat Model

OBJECTIVES

To examine the anti-inflammatory properties and underlying mechanisms of Tongfeng Li'an Granules (TFLA), a traditional medicine, in acute gouty arthritis using a rat model.

MATERIALS AND METHODS

We identified 55 major compounds in TFLA via ultrahigh-performance liquid chromatography connected to quadrupole time-of-flight mass spectrometry (UPLC-TQF-MS/MS). Databases were employed for the prediction of potential targets, followed by PPI network construction as well as GO and KEGG analyses. After network-pharmacology-based analysis, a rat gouty arthritis model was used to validate the anti-inflammatory mechanism of TFLA.

RESULTS

UPLC-TQF-MS/MS and network pharmacology analyses revealed 55 active ingredients and 160 targets of TFLA associated with gouty arthritis, forming an ingredient-target-disease network. The PPI network identified 20 core targets, including TLR2, TLR4, IL6, NFκB, etc. Functional enrichment analyses highlighted the Toll-like receptor signaling pathway as significantly enriched by multiple targets, validated in in vivo experiments. Animal experiments demonstrated that TFLA improved pathological changes in gouty joint synovium, with decreased ankle joint circumference, serum IL6, IL10, and TNFα levels, as well as reduced protein and mRNA expression of NLRP3, TLR2, and TLR4 in ankle joint synovial tissue observed in the middle- and high-dose TFLA and positive control groups compared to the model group (p < 0.05).

CONCLUSION

This research elucidated the pharmacological mechanisms of TFLA against gouty arthritis, implicating various ingredients, targets, and signaling pathways. Animal experiments confirmed TFLA's efficacy in alleviating inflammation in acute gouty arthritis by modulating Toll-like receptor signaling and NLRP3 expression.

Development and assessment of the Quality of Life Instruments for Chronic Diseases-Gout (QLICD-GO) (V2.0)

OBJECTIVE

To develop and assess the Quality of Life Instruments for Chronic Diseases-Gout QLICD-GO (V2.0).

METHODS

The instrument was developed using a programmatic decision-making method to combine the general module of the Quality of Life Instruments for Chronic Diseases and a new specific module. The instrument was assessed by measuring the quality of life of 116 patients with gout.

RESULTS

The QLICD-GO (V2.0) included 28 items from the general module of chronic diseases and 12 items in three facets from the specific module. In addition to the field of physiological function, the internal consistency reliability of other fields and dimensions of the instrument was > 0.7, and the split-half reliability was > 0.5. Three common factors were extracted from the specific module, with a cumulative variance contribution rate of 57.54%. The standardized response means of the specific module and the whole instrument were 0.94 and 1.20, respectively.

CONCLUSIONS

The QLICD-GO (V2.0) has good reliability, validity, and responsiveness. The instrument comprehensively and objectively reflects the quality of life of patients with gout, and it can be used to assess treatment regimens developed by medical staff. Key Points • The QLICD-GO (V2.0) has been developed for patients with gout based upon the foundation of the QLICD-GM. • The QLICD-GO reflects the clinical signs and symptoms, drug-related side effects, and psychological changes specific to patients with gout. • Based on the assessment results, the QLICD-GO (V2.0) has good reliability, validity, and responsiveness. • QLICD-GO (V2.0) can objectively and comprehensively reflect the QOL of patients with gout and can be used by clinical staff to assess treatment regimens.

Association between glucokinase regulator gene polymorphisms and serum uric acid levels in Taiwanese adolescents

The glucokinase regulator gene (GCKR) is located on chromosome 2p23. It plays a crucial role in maintaining plasma glucose homeostasis and metabolic traits. Recently, genome-wide association studies have revealed a positive association between hyperuricemia and GCKR variants in adults. This study investigated this genetic association in Taiwanese adolescents. Data were collected from our previous cross-sectional study (Taipei Children Heart Study). The frequencies of various genotypes (CC, CT, and TT) or alleles (C and T) of the GCKR intronic single-nucleotide polymorphism (SNP) rs780094 and the coding SNP rs1260326 (Pro446Leu, a common 1403C-T transition) were compared between a total of 968 Taiwanese adolescents (473 boys, 495 girls) with hyperuricemia or normal uric acid levels on the basis of gender differences. Logistic and linear regression analyses explored the role of GCKR in abnormal uric acid (UA) levels. Boys had higher UA levels than girls (6.68 ± 1.29 and 5.23 ± 0.95 mg/dl, respectively, p < 0.001). The analysis of both SNPs in girls revealed that the T allele was more likely to appear in patients with hyperuricemia than the C allele. After adjusting for confounders, the odds ratio (OR) for hyperuricemia incidence in the TT genotype was 1.75 (95% confidence interval [CI] 1.02–3.00), which was higher than that in the C allele carriers in rs1260326 in the girl population. Similarly, the TT genotypes had a higher risk of hyperuricemia, with an OR of 2.29 (95% CI 1.11–4.73) for rs1260326 and 2.28 (95% CI 1.09–4.75) for rs780094, than the CC genotype in girl adolescents. The T (Leu446) allele of GCKR rs1260326 polymorphism is associated with higher UA levels in Taiwanese adolescent girls.

SLC2A9 rs1014290 Polymorphism is Associated with Prediabetes and Type 2 Diabetes

PURPOSE

To investigate the association of the A/G rs1014290 polymorphism in SLC2A9 with type 2 diabetes (T2DM) and prediabetes mellitus (pre-DM). Patients and Methods. We enrolled 1058 patients who attended the Hebei General Hospital, Shijiazhuang, Hebei Province, China. The patients underwent general testing and oral glucose tolerance tests and were divided into three groups: 352 patients newly diagnosed with T2DM, 358 patients with pre-DM, and 348 healthy controls. The single nucleotide polymorphism (SNP) was detected by ligase detection reactions. The χ ² test, one-way ANOVA, and binary logistic regression analysis were used to analyze the results.

RESULTS

In the T2DM group, the GG genotype frequency at the rs1014290 locus was significantly lower (14.8%) than it was in the healthy controls. Furthermore, the GG genotype group was associated with a reduced risk of T2DM in unadjusted and confounder-adjusted models compared with the risk in the AA genotype group. The G allele in the SLC2A9 rs1014290 locus decreased susceptibility to T2DM. In the pre-DM group, the GG and AG genotype groups had no significant correlation with the risk of pre-DM in any of the models. In the T2DM group, the uric acid level was significantly lower in the GG genotype group. In the T2DM and pre-DM groups, the HOMA-β levels were significantly higher in the GA (P  < 0.001) and GG (P  < 0.001) genotype groups than it was in the AA genotype group, and HOMA-IR was significantly lower in the GA (P  < 0.001) and GG (P  < 0.001) genotype groups than it was in the AA genotype group.

CONCLUSION

The A/G (rs1014290) SNP in SLC2A9 is closely related to the occurrence and development of diabetes.

The association between genetic polymorphisms in ABCG2 and SLC2A9 and urate: an updated systematic review and meta-analysis

Background

Replication studies showed conflicting effects of ABCG2 and SLC2A9 polymorphisms on gout and serum urate. This meta-analysis therefore aimed to pool their effects across studies.

Methods

Studies were located from MEDLINE and Scopus from inception to 17th June 2018. Observational studies in adults with any polymorphism in ABCG2 or SLC2A9, and outcome including gout, hyperuricemia, and serum urate were included for pooling. Data extractions were performed by two independent reviewers. Genotype effects were pooled stratified by ethnicity using a mixed-effect logistic model and a multivariate meta-analysis for dichotomous and continuous outcomes.

Results

Fifty-two studies were included in the analysis. For ABCG2 polymorphisms, mainly studied in Asians, carrying 1–2 minor-allele-genotypes of rs2231142 and rs72552713 were respectively about 2.1–4.5 and 2.5–3.9 times higher odds of gout than non-minor-allele-genotypes. The two rs2231142-risk-genotypes also had higher serum urate about 11–18 μmol/l. Conversely, carrying 1–2 minor alleles of rs2231137 was about 36–57% significantly lower odds of gout. For SLC2A9 polymorphisms, mainly studied in Caucasians, carrying 1–2 minor alleles of rs1014290, rs6449213, rs6855911, and rs7442295 were about 25–43%, 31–62%, 33–64%, and 35–65% significantly lower odds of gout than non-minor-allele-genotypes. In addition, 1–2 minor-allele-genotypes of the latter three polymorphisms had significantly lower serum urate about 20–49, 21–51, and 18–54 μmol/l than non-minor-allele-genotypes.

Conclusions

Our findings should be useful in identifying patients at risk for gout and high serum urate and these polymorphisms may be useful in personalized risk scores.

Trial registration

PROSPERO registration number: CRD42018105275.

Supplementary information

The online version contains supplementary material available at 10.1186/s12881-020-01147-2.

Trans-ancestral dissection of urate- and gout-associated major loci SLC2A9 and ABCG2 reveals primate-specific regulatory effects

Gout is a complex inflammatory arthritis affecting ~20% of people with an elevated serum urate level (hyperuricemia). Gout and hyperuricemia are essentially specific to humans and other higher primates, with varied prevalence across ancestral groups. SLC2A9 and ABCG2 are major loci associated with both urate and gout in multiple ancestral groups. However, fine mapping has been challenging due to extensive linkage disequilibrium underlying the associated regions. We used trans-ancestral fine mapping integrated with primate-specific genomic information to address this challenge. Trans-ancestral meta-analyses of GWAS cohorts of either European (EUR) or East Asian (EAS) ancestry resulted in single-variant resolution mappings for SLC2A9 (rs3775948 for urate and rs4697701 for gout) and ABCG2 (rs2622621 for gout). Tests of colocalization of variants in both urate and gout suggested existence of a shared candidate causal variant for SLC2A9 only in EUR and for ABCG2 only in EAS. The fine-mapped gout variant rs4697701 was within an ancient enhancer, whereas rs2622621 was within a primate-specific transposable element, both supported by functional evidence from the Roadmap Epigenomics project in human primary tissues relevant to urate and gout. Additional primate-specific elements were found near both loci and those adjacent to SLC2A9 overlapped with known statistical epistatic interactions associated with urate as well as multiple super-enhancers identified in urate-relevant tissues. We conclude that by leveraging ancestral differences trans-ancestral fine mapping has identified ancestral and functional variants for SLC2A9 or ABCG2 with primate-specific regulatory effects on urate and gout.

An update on the genetics of hyperuricaemia and gout

A central aspect of the pathogenesis of gout is elevated urate concentrations, which lead to the formation of monosodium urate crystals. The clinical features of gout result from an individual's immune response to these deposited crystals. Genome-wide association studies (GWAS) have confirmed the importance of urate excretion in the control of serum urate levels and the risk of gout and have identified the kidneys, the gut and the liver as sites of urate regulation. The genetic contribution to the progression from hyperuricaemia to gout remains relatively poorly understood, although genes encoding proteins that are involved in the NLRP3 (NOD-, LRR- and pyrin domain-containing 3) inflammasome pathway play a part. Genome-wide and targeted sequencing is beginning to identify uncommon population-specific variants that are associated with urate levels and gout. Mendelian randomization studies using urate-associated genetic variants as unconfounded surrogates for lifelong urate exposure have not supported claims that urate is causal for metabolic conditions that are comorbidities of hyperuricaemia and gout. Genetic studies have also identified genetic variants that predict responsiveness to therapies (for example, urate-lowering drugs) for treatment of hyperuricaemia. Future research should focus on large GWAS (that include asymptomatic hyperuricaemic individuals) and on increasing the use of whole-genome sequencing data to identify uncommon genetic variants with increased penetrance that might provide opportunities for clinical translation.

Influence of Genetic and Non-Genetic Risk Factors for Serum Uric Acid Levels and Hyperuricemia in Mexicans

Risk of hyperuricemia is modified by genetic and environmental factors. Our aim was to identify factors associated with serum uric acid levels and hyperuricemia in Mexicans. A pilot Genome-wide association study GWAS was performed in a subgroup of participants (n = 411) from the Health Workers Cohort Study (HWCS). Single nucleotide polymorphisms (SNPs) associated with serum uric acid levels were validated in all the HWCS participants (n = 1939) and replicated in independent children (n = 1080) and adult (n = 1073) case-control studies. The meta-analysis of the whole HWCS and replication samples identified three SLC2A9 SNPs: rs1014290 (p = 2.3 × 10⁻⁶⁴), rs3775948 (p = 8.2 × 10⁻⁶⁴) and rs11722228 (p = 1.1 × 10⁻¹⁷); and an ABCG2 missense SNP, rs2231142 (p = 1.0 × 10⁻¹⁸). Among the non-genetic factors identified, the visceral adiposity index, smoking, the metabolic syndrome and its components (waist circumference, blood pressure, glucose and hyperlipidemia) were associated with increased serum uric acid levels and hyperuricemia (p < 0.05). Among the female HWCS participants, the odds ratio for hyperuricemia was 1.24 (95% CI, 1.01–1.53) per unit increase in soft drink consumption. As reported in other studies, our findings indicate that diet, adiposity and genetic variation contribute to the elevated prevalence of hyperuricemia in Mexico.

Urate-lowering therapy alleviates atherosclerosis inflammatory response factors and neointimal lesions in a mouse model of induced carotid atherosclerosis

Hyperuricemia (HU) is a cause of gout. Clinical studies show a link between HU and cardiovascular disease. However, the role of soluble serum urate (SU) on atherosclerosis development remains elusive. We aimed to use a new HU mouse model [Uricase/Uox knockout (KO)] to further investigate the relationship between HU and atherosclerosis. A mouse model by perivascular collar placement of induced carotid atherosclerosis was established in male Uox-KO mice. The Uox-KO mice had elevated SU levels and enhanced levels of atherosclerosis inflammatory response proteins. In contrast, Uox-KO mice with carotid atherosclerosis showed severe neointimal changes in histology staining consistent with increases in intimal area and increases in proliferating cell nuclear antigen (PCNA)- and F4/80-positive cells. Allopurinol reduced neointimal areas induced by the perivascular collar in hyperuricemic mice, accompanied by decreased expression of PCNA- and F4/80-positive cells. Urate-lowering treatment alleviated atherosclerosis inflammatory response factors and reactive oxygen species (ROS) intensities in both collar placement Uox-KO mice and urate-stimulated human umbilical vein endothelial cells (HUVECs). In vitro results using HUVECs showed ROS was induced by urate and ROS induction was abrogated using antioxidants. These data demonstrate that urate per se does not trigger atherosclerosis intima lesions in male mice. Urate worsens carotid neointimal lesions induced by the perivascular collar and urate-lowering therapy partially abrogates the effects. The current study warrants clinical studies on the possible benefits of urate-lowering therapy in atherosclerosis patients with HU.

Polymorphisms of ABCG2 and SLC22A12 Genes Associated with Gout Risk in Vietnamese Population

Background and objective: Gout is a common form of inflammatory arthritis caused by the crystallization of uric acid. Previous studies have demonstrated that the genetic predisposition of gout varies in different ethnic populations. However the association study of genetic variants with gout remains unknown in the Vietnamese population. Our study aimed to assess the relationship between polymorphisms in ABCG2 and SLC22A12 and gout susceptibility in Vietnamese. Materials and methods: Genomic DNA was extracted from blood of a total of 170 patients with gout and 351 healthy controls. We genotyped single nucleotide polymorphisms (SNPs): rs72552713, rs12505410 of the ABCG2 gene and rs11231825, rs7932775 of the SLC22A12 gene using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and then confirmed 10% of randomly selected subjects by Sanger sequencing. Results: Three SNPs (rs72552713 and rs12505410 and rs11231825) were in accordance with Hardy–Weinberg Equilibrium (HWE) (p > 0.05) while rs7932775 was not (p < 0.05). For rs72552713, CT genotype was significantly different between gout patient and control groups (p < 0.001) and the T allele was associated with an increased risk of gout (OR = 21.19; 95% CI: 3.00–918.96; p < 0.001). Serum uric acid and hyperuricemia differed significantly between CC and CT genotype groups (p = 0.004 and 0.008, respectively). For rs11231825, a protective effect against gout risk was identified in the presence of the C allele when compared with the T allele (OR = 0.712; 95% CI: 0.526–0.964 p = 0.0302). In contrast, no significant difference of allele frequencies between gout patients and controls was detected for rs12505410 (p > 0.05). However, significant differences in serum uric acid and systolic blood pressure were obtained among gout patients. Conclusion: Our results suggest that ABCG2 rs72552713 and SLC22A12 rs11231825 are likely associated with gout in the Vietnamese population in which T allele may be a risk factor for gout susceptibility.

The Bidirectional Effect of Defective ALDH2 Polymorphism and Disease Prevention

Despite the role of aldehyde dehydrogenase 2 (ALDH2) in the detoxification of endogenous aldehydes, the defective polymorphism (rs671), which is highly prevalent among East Asians, does not show a serious phenotype, such as congenital abnormality. However, unfavorable and favorable impacts of the variant allele, ALDH2*2, on various disease risks have been reported. The underlying mechanisms are often complicated due to the compensatory aldehyde detoxification systems. As the phenotypes emerge due to overlapping environmental factors (e.g., alcohol intake and tobacco smoke) or individual vulnerabilities (e.g., aging and apolipoprotein E ε4 allele), polymorphism is therefore considered to be important in the field of preventative medicine. For example, it is important to recognize that ALDH2*2 carriers are at a high risk of alcohol drinking-related cancers; however, their drinking habit has less adverse effects on physiological indices, such as blood pressure, body mass index, levels of lipids, and hepatic deviation enzymes in the blood, than in non-ALDH2*2 carriers. Therefore, opportunities to reconsider their excessive drinking habit before adverse events occur can be missed. To perform effective disease prevention, the effects of ALDH2*2 on various diseases and the biological mechanisms should be clarified.

Multiple Membrane Transporters and Some Immune Regulatory Genes are Major Genetic Factors to Gout

Gout is a common form of inflammatory arthritis caused by hyperuricemia and the deposition of Monosodium Urate (MSU) crystals. It is also considered as a complex disorder in which multiple genetic factors have been identified in association with its susceptibility and/or clinical outcomes. Major genes that were associated with gout include URAT1, GLUT9, OAT4, NPT1 (SLC17A1), NPT4 (SLC17A3), NPT5 (SLC17A4), MCT9, ABCG2, ABCC4, KCNQ1, PDZK1, NIPAL1, IL1β, IL-8, IL-12B, IL-23R, TNFA, MCP-1/CCL2, NLRP3, PPARGC1B, TLR4, CD14, CARD8, P2X7R, EGF, A1CF, HNF4G and TRIM46, LRP2, GKRP, ADRB3, ADH1B, ALDH2, COMT, MAOA, PRKG2, WDR1, ALPK1, CARMIL (LRRC16A), RFX3, BCAS3, CNIH-2, FAM35A and MYL2-CUX2. The proteins encoded by these genes mainly function in urate transport, inflammation, innate immunity and metabolism. Understanding the functions of gout-associated genes will provide important insights into future studies to explore the pathogenesis of gout, as well as to develop targeted therapies for gout.

[Importance of an Aldehyde Dehydrogenase 2 Polymorphism in Preventive Medicine]

Unlike genetic alterations in other aldehyde dehydrogenase (ALDH) isozymes, a defective ALDH2 polymorphism (rs671), which is carried by almost half of East Asians, does not show a clear phenotype such as a shortened life span. However, impacts of a defective ALDH2 allele, ALDH2*2, on various disease risks have been reported. As ALDH2 is responsible for the detoxification of endogenous aldehydes, a negative effect of this polymorphism is predicted, but bidirectional effects have been actually observed and the mechanisms underlying such influences are often complex. One reason for this complexity may be the existence of compensatory aldehyde detoxification systems and the secondary effects of these systems. There are many issues to be addressed with regard to the ALDH2 polymorphism in the field of preventive medicine, including the following concerns. First, ALDH2 in the fetal stage plays a role in aldehyde detoxification; therefore, prenatal health effects of environmental aldehyde exposure are of concern for ALDH2*2-carrying fetuses. Second, ALDH2*2 carriers are at high risk of drinking-related cancers. However, their drinking habits result in less worsening of physiological findings, such as energy metabolism index and liver functions, compared with non-ALDH2*2 carriers, and therefore opportunities to detect excessive drinking can be lost. Third, personalized medicine such as personalized prescriptions for ALDH2*2 carriers will be required in the clinical setting, and accumulation of evidence is awaited. Lastly, since the ALDH2 polymorphism is not considered in workers' limits of exposure to aldehydes and their precursors, efforts to lower exposure levels beyond legal standards are required.