Combination of Uric Acid and Pro-Inflammatory Cytokines in Discriminating Patients with Gout from Healthy Controls

Advancements in the study of IL-6 and its receptors in the pathogenesis of gout

Gout is an autoinflammatory disease characterized by the deposition of monosodium urate crystals in or around the joints, primarily manifesting as inflammatory arthritis that recurs and resolves spontaneously. Interleukin-6 (IL-6) is a versatile cytokine with both anti-inflammatory and pro-inflammatory capabilities, linked to a variety of inflammatory diseases such as gouty arthritis, rheumatoid arthritis, inflammatory bowel disease, vasculitis, and several types of cancer. The rapid production of IL-6 during infections and tissue damage aids in host defense. However, excessive synthesis of IL-6 and dysregulation of its receptor signaling (IL-6R) might contribute to the pathology of diseases. Recent advancements in clinical and basic research, along with developments in animal models, have established the significant role of IL-6 and its receptors in the pathogenesis of gout, although the precise mechanisms remain to be fully elucidated. This review discusses the role of IL-6 and its receptors in gout progression and examines contemporary research on modulating IL-6 and its signaling pathways for treatment. It aims to provide insights into the pathogenesis of gout and to advance the development of targeted therapies for gout-related inflammation.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Elucidating the mechanism of the Tibetan medicine sanguotang in treating gouty arthritis through network pharmacology and in vivo experiments

BACKGROUND

We explored the mechanisms of Sanguotang (SGT), a Tibetan medicine, in treating gout arthritis (GA).

METHODS

The main active components, action targets, and disease targets of SGT were identified through TCMSP databases. The gene functions were analyzed using protein interaction (PPI) networks, Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and molecular docking. A GA model induced by monosodium urate was established in rats. The ankle joint swelling was observed. The levels of uric acid (UA) and albumin (ALB) in rat serum were measured. Hematoxylin and eosin (HE) staining was conducted to examine the pathological changes in rat ankle joints.

RESULTS

Twenty-nine active components of SGT with proven efficacy and 66 intersection targets were identified, primarily involved in inflammation and immune regulation pathways. The PPI results revealed that the key targets of SGT against GA included ALB, IL6, TNF, TP53, and PTGS. Molecular docking showed favorable binding energy between the ALB protein and the active components. The results from animal experiments demonstrated that SGT effectively alleviated the inflammatory reaction in ankle joints, and decreased UA and ALB levels. Furthermore, SGT effectively inhibited the proliferation of synovial cells in the ankle joint cavity, prevented infiltration of inflammatory cells, and protected synovial tissue, thereby improving GA.

CONCLUSIONS

SGT comprehensively contributes to the treatment of GA by regulating UA metabolism, reducing the release of inflammatory factors, and modulating immune and inflammatory pathways.

Comparison of the therapeutic effects of febuxostat combined with a low-purine diet and allopurinol combined with a low-purine diet on the improvement of gout patients

OBJECTIVE

To compare the clinical efficacy of febuxostat combined with a low-purine diet versus allopurinol combined with a low-purine diet in the treatment of gout.

METHODS

In this prospective controlled trial, 98 gout patients admitted to our hospital from February 2021 to December 2022 were enrolled as study subjects. Patients were randomly assigned to the study group (febuxostat combined with a low-purine diet) and the control group (allopurinol combined with a low-purine diet), with 49 patients in each group. The therapeutic effect was evaluated based on joint function and serum uric acid levels after treatment, and classified into three levels: markedly effective, effective, and ineffective. The levels of inflammatory factors, including tumor necrosis factor-a (TNF-a), cytokine interleukin-1beta (IL-1β), and interleukin (IL)-18 (IL-18), were collected. The Numeric Rating Scale (NRS) was used to assess the degree of pain in patients. Clinical indicators before and 6 months after treatment were compared between the two groups.

RESULTS

There was no statistically significant difference in age and gender between the two groups. After 6 months of treatment, the effective rate in the study group (48 cases, 97.96%) was higher than that in the control group (42 cases, 85.71%), with a statistically significant difference (p = .027). At the same time, the study group had significantly lower levels of serum uric acid (162.39 μmol/L ± 17.23 μmol/L vs. S198.32 μmol/L ± 18.34 μmol/L, p < .001), creatinine (87.39 mmol/L ± 9.76 mmol/L vs. 92.18 mmol/L ± 9.27 mmol/L, p = .014), total cholesterol (3.65 mmol/L ± 0.65 mmol/L vs. 4.76 mmol/L ± 0.73 mmol/L, p < .001), and triglycerides (1.76 mmol/L ± 0.32 mmol/L vs. 2.28 mmol/L ± 0.41 mmol/L, p < .001) compared to the control group, with statistically significant differences (p < .05). After treatment, the levels of inflammatory factors and degree of pain in the study group were significantly lower than those in the control group (all p < .05). During the treatment process, the incidence of adverse reactions in the study group (2 cases, 4.08%) was lower than that in the control group (9 cases, 18.37%), with a statistically significant difference (p = .025).

CONCLUSION

Febuxostat combined with a low-purine diet can reduce inflammatory factors and alleviate the degree of pain in gout patients, significantly improving their clinical symptoms.

Upadacitinib sustained-release tablets for the treatment of chronic refractory gouty arthritis: a case report and literature review

Background

Gouty arthritis (GA) is a crystal-related joint disease caused by the deposition of monosodium urate (MSU) crystals, directly associated with hyperuricemia resulting from purine metabolism disorder and/or reduced uric acid excretion. Acute attacks of typical gouty arthritis are generally relieved through the clinical use of NSAIDs, colchicine, or glucocorticoids. However, managing patients with chronic refractory gout poses challenges due to complications such as multiple tophi, gouty nephropathy, diabetes, and gastrointestinal bleeding. While there have been numerous studies on gout in recent years, research specifically regarding chronic refractory gout remains limited. The management of such cases still faces several unresolved issues, including recurrent disease flare-ups and poor patient compliance leading to inadequate drug utilization and increased risk of side effects. In this report, we present a case of successful improvement in chronic refractory gouty arthritis using the biologic agent upadacitinib sustained-release tablets.

Case presentation

Our case report involves a 53 years-old Asian patient with recurrent gouty arthritis who had a history of over 20 years without regular treatment, presenting with tophi and an increasing number of painful episodes. During hospitalization, various analgesics and anti-inflammatory drugs provided inadequate relief, requiring the use of steroids to alleviate symptoms. However, tapering off steroids proved challenging. We decided to add upadacitinib sustained-release tablets to the treatment regimen, which ultimately improved the patient's condition. After 6 months of follow-up, the patient has not experienced any further acute pain episodes.

Conclusion

This case highlights the potential therapeutic effect of upadacitinib sustained-release tablets during the acute phase of chronic refractory gouty arthritis.

Alterations in articular cartilage frictional properties in the setting of acute gouty arthritis

The tribological behaviour of articular cartilage plays a key role in joint motion; however, there is a gap in research on the effect of hyperuricemic joint fluid on cartilage friction behaviour in acute gouty arthritis. In this study, we carried out a fixed-load scratch experiment to compare the friction and wear of articular cartilage under the lubrication of gouty arthritis arthritic fluid and normal human arthritic fluid, and the results showed that the cartilage friction coefficient of patients with acute gouty arthritis was significantly larger than that of normal human beings, and that the cartilage friction coefficient decreased with the elevation of normal load and sliding speed, and the change with the sliding speed varied more differently from that of normal human beings, and that the cartilage surface wear was more severe after prolonged friction. The wear and tear of the cartilage surface is more severe after prolonged friction. Patients with gouty arthritis should reduce the sudden speed changes such as fast running and variable speed running to maintain the stability of the cartilage surface friction coefficient.

Correlation between gout and dry eye disease

BACKGROUND

Gout is a common form of inflammatory arthritis that can cause a number of serious complications. Complications are common in patients with gout and complicate their management and disease outcome. The recent literature has reported that an increasing number of gout patients are presenting with dry eye symptoms. However, until now, the link between gout and dry eye disease has not been clearly defined. (It is unclear whether the two conditions simply co-exist, whether there are common risk factors, or whether dry eye disease is a complication of gout.) METHODS: A thorough literature search was conducted in the PubMed database to summarize the most recent information on the correlation between gout and dry eye disease and to explore the potential relationship between the pathogenesis of the two. (Objective: Therefore, in this paper, we review the recent literature on the correlation between gout and dry eye disease and explore the potential association between the pathogenesis of both.) RESULTS: Studies in the last five years have shown a correlation between gout and dry eye, i.e., gout is associated with an increased risk of dry eye. The NLRP3-IL-1β signaling pathway may be a potential mechanism for the combination of gout and dry eye disease; factors such as high blood uric acid and xanthine oxidase activation in gout patients may aggravate the development of dry eye disease; reducing the use of visual display terminals; reducing or abstaining from alcohol consumption; and moderate coffee intake may effectively prevent gout and dry eye disease.

CONCLUSIONS

It is an undisputed fact that many gout patients present with dry eye manifestations that seriously affect the quality of life of gout patients, and early detection and treatment of dry eye in gout patients are crucial.

Increased Metallothionein-1 Associated with Gout Activity and Tophi

BACKGROUND AND AIMS

Gout is a chronic self-limiting inflammatory arthritis. An increase in metallothionein-1 (MT-1) has been reported in rheumatoid arthritis and osteoarthritis, and it attenuates inflammation and the pathology of diseases. This study aims to detect MT-1 levels in patients with gout and to explore its correlation with disease activity, clinical indexes, and inflammatory cytokines.

METHODS

The expression of MT-1 messenger RNAs (mRNAs) and protein levels in patients with gout were measured using real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Correlations between MT-1 and clinical indexes or inflammatory mediators were analyzed using Spearman's correlation test.

RESULTS

Compared with healthy controls (HCs, n = 43), patients with active gout (n = 27) showed higher levels of MT-1 mRNA in peripheral blood mononuclear cells and protein in serum, particularly those with tophi. No significant difference in serum MT-1 levels was observed among patients with inactive gout, HCs, and patients with hyperuricemia without gout. Furthermore, no significant difference was observed between patients with gout with kidney damage and HCs. In addition, serum interleukin (IL)-1β, IL-6, and IL-8 levels were significantly increased in patients with active gout, particularly in those with tophi. The serum MT-1 level was positively correlated with C-reactive protein, as well as with IL-1β, IL-6, and IL-18.

CONCLUSION

The higher levels of MT-1 were found in patients with gout, which were correlated with disease activity and gout related pro-inflammatory cytokines. Indicating MT-1 may serve as a new marker for predicting disease activity.Abbreviations: IL-1β: Interleukin 1β; MT-1: Metallothionein-1; CRP: C-Reactive Protein; ROS: Reactive Oxygen Species; IL-10: Interleukin 10; TGF-β: Transforming Growth Factor Beta.

Joint Application of Multiple Inflammatory Cytokines in Diagnosis of Gout Flare

Purpose

This study aimed to explore the accuracy for joint application of inflammatory cytokines in diagnosis of gout flare by comparison with peripheral blood cells.

Methods

We collected the clinical data of 96 acute gout patients and 144 remission gout patients, and compared the levels of peripheral blood cells, inflammatory cytokines and blood biochemistry indexes between acute and remission gout. We respectively assessed the area under curves (AUCs) for single and multiple inflammatory cytokines including C-reactive protein (CRP), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and single and multiple peripheral blood cells including platelet (PLT), white blood cell (WBC), percentages of neutrophils (N%), lymphocytes (L%), eosinophils (E%), basophils (B%) in diagnosis of acute gout by receiver operating characteristic (ROC) curve analysis.

Results

By contrast with remission gout, the levels of PLT, WBC, N%, CRP, IL-1β, IL-6 and TNF-α increased, and the levels of L%, E% and B% decreased in acute gout. The AUCs of PLT, WBC, N%, L%, E% and B% in diagnosis of acute gout were respectively 0.591, 0.601, 0.581, 0.567, 0.608 and 0.635, while the AUC for joint application of these peripheral blood cells was 0.674. Moreover, the AUCs of CRP, IL-1β, IL-6 and TNF-α in diagnosis of acute gout were respectively 0.814, 0.683, 0.622 and 0.746, while the AUC for joint application of these inflammatory cytokines was 0.883, reflecting significantly higher levels than peripheral blood cells.

Conclusion

The joint application of multiple inflammatory cytokines can better distinguish acute gout from remission gout compared with peripheral blood cells.

Association of Total Calcium With Serum Uric Acid Levels Among United States Adolescents Aged 12-19 Years: A Cross-Sectional Study

Aims

Evidence of a link between total calcium (CA) and serum uric acid (SUA) is absent in adolescents. Thus, this study aimed to determine the relationship between total CA levels and SUA levels in United States adolescents.

Methods

A cross-sectional study analyzed a sample composed of 8,309 United States adolescents aged 12–19 years from the National Health and Nutrition Examination Survey database (1999–2006 survey cycle). Multivariable linear regression analyses and multivariable logistic regression analyses were used to assess the correlation of total CA with SUA levels and hyperuricemia. Furthermore, the dose-response relationship of total CA and SUA levels was analyzed using smooth curve fitting (penalized spline method).

Results

According to multivariable linear regression analysis, every 1 mg/dL increase in total CA level is associated with a 0.33 mg/dL (β = 0.33, 95% CI: 0.27–0.40, p < 0.001) increase in SUA. Multivariable logistic regression analyses showed that every 0.1 mg/dL increase in total CA level is linked with an 8% increased risk of hyperuricemia (OR = 1.08, 95% CI: 1.06–1.10, p < 0.001). The analyses of smooth curve fitting revealed that total CA levels were linearly correlated with SUA levels (P_{non–linearity} = 0.152). The results were highly stable in all subgroups. The interaction analysis results presented that race/ethnicity had an interactive role in associating total CA with SUA levels.

Conclusions

In United States adolescents, total CA levels were linearly and positively correlated with SUA levels.