A review on gout: Looking back and looking ahead

Terminalia chebula Retz. extract relieves gout arthritis by inhibiting xanthine oxidase, the uric acid transporter, and NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Gout is a metabolic disorder accompanied by high serum uric acid levels and joint inflammation due to disturbances in purine metabolism in the body. The dried fruit of Terminalia chebula Retz. is recorded in the "Four Medical Tantras" for the treatment of gout and the core anti-gout component of the Tibetan clinical prescription, such as TongFengTangSan. However, the anti-gout efficacy has not been reported yet.

AIM OF STUDY

To evaluate the anti-gout effect and mechanisms of Terminalia chebula Retz. in gout model rats.

MATERIALS AND METHODS

First, the components of the Terminalia chebula Retz. extract were detected and characterized using ultra performance liquid chromatography with quadrupole time-of-flight mass spectrometry technology. A gout model was established using the continuous intragastric administration of 200 mg/kg of potassium oxonate and 300 mg/kg of hypoxanthine for 44 days, and 8 mg monosodium urate suspension was injected once in the joint cavity on the 42nd day. One hour after modeling, Terminalia chebula Retz. extract was administered by gavage at low, medium, and high doses. The corresponding biochemical indicators at the protein and gene levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot.

RESULTS

A total of 149 compounds, comprising 23 phenolic acids, 104 tannins, 5 flavonoids, 14 terpenoids, and three other compounds, were identified in Terminalia chebula Retz. extract using the ultra performance liquid chromatography with quadrupole time-of-flight mass spectrometry method. The in vivo pharmacodynamics experiments showed that Terminalia chebula Retz. extract significantly reduced the serum uric acid level, the ankle swelling level, and the level of inflammatory factors in the gout rats. Terminalia chebula Retz. extract also decreased the serum xanthine oxidase, alanine aminotransferase, aspartate aminotransferase and diamine oxidase activity of the gout rats. The western blot and PCR experiments showed that treatment with Terminalia chebula Retz. extract down-regulated the mRNA and protein levels of urate transporter 1 and glucose transporter 9 in the kidney tissues. An immunofluorescence experiment revealed that Terminalia chebula Retz. extract strengthened the intestinal barrier by the up-regulation on the protein expression of occludin and zonula occludens-1 in the ileum. In addition, Terminalia chebula Retz. extract was found to alleviate inflammation by inactivating the renal NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome and the synovial membranes of joints. Terminalia chebula Retz. treatment down-regulated the protein or mRNA levels of NLRP3 inflammasome family members, including toll-like receptor 4, toll-like receptor 2, NLRP3, nuclear factor kappa-B, apoptosis-associated speck-like protein containing a CARD and interleukin-1β.

CONCLUSION

This study demonstrated that Terminalia chebula Retz. extract alleviated gout symptoms through the dual effects of lowering UA and relieving inflammation through inhibiting NLRP3 inflammasome activation.

Sinomenine alleviates gouty inflammation by inhibiting macrophage M1 polarization and neutrophil extracellular trap formation

Gout is a common inflammatory arthropathy characterized by the deposition of monosodium urate (MSU) crystals, leading to severe pain and swelling. Sinomenine (SIN) is the major active component of Sinomenium acutum. SIN has been demonstrated to exert preventive and therapeutic effects on arthritis in cell-based, animal, and clinical studies. The present study focused on the efficacy and role of SIN in relieving symptoms of gouty inflammation in vivo and in vitro. The anti-inflammatory effects of SIN were evaluated in mice with MSU-induced air-pouch via hematoxylin-eosin (HE) staining, and enzyme-linked immunosorbent assay (ELISA). Transcriptomic analysis revealed that SIN modulates a range of inflammatory pathways associated with gout pathogenesis. Notably, the NOD-like receptor pathway and neutrophil extracellular trap (NET) formation were significantly enriched with the occurrence of gout and significantly improved after SIN treatment. THP-1 macrophages were stimulated with PBS or MSU, with or without SIN. Immunofluorescence (IF) and western blotting (WB) results indicated that SIN suppressed NOD-like receptor thermal protein domain associated protein 3 (NLRP3)/interleukin-1β (IL-1β) expression. Additionally, SIN inhibited macrophage M1 polarization and NET formation. In summary, SIN ameliorates gouty inflammation, likely by regulating the NLRP3/IL-1β pathway, M1 macrophage polarization, and NET formation. Thus, SIN is a promising drug for treating gout.

Therapeutic potential and pharmacological mechanisms of Traditional Chinese Medicine in gout treatment

Gout is a systemic metabolic disorder caused by elevated uric acid (UA) levels, affecting over 1% of the population. The most common complication of gout is gouty arthritis (GA), characterized by swelling, pain or tenderness in peripheral joints or bursae, which can lead to the formation of tophi. At present, western medicines like colchicine, febuxostat and allopurinol are the primary treatment strategy to alleviate pain and prevent flare-ups in patients with GA, but they have significant side effects and increased mortality risks. Traditional Chinese medicine (TCM) has been utilized for thousands of years for the prevention and treatment of GA, demonstrating effective control over serum UA (SUA) levels with fewer side effects. Herein we summarized a total of 541 studies published from 2000 to 2023 in sources including PubMed, Web of Science, the Cochrane Library and Embase, highlighting the therapeutic potential of TCM in treating gout and GA, particularly in combination with modern medical strategies. This review focuses on TCM formulas, Chinese herbal extracts, and active compounds derived from TCM, providing an overview of recent clinical application and the pharmacological research based on animal models and cellular systems. Particularly, the current review categorized the clinical and experimental evidence into the strategies for improving hyperuricemia, decreasing the sudden onset of acute GA and retarding chronic GA progression, supplied further coherent reference and enlightenment for clinicians, investigators of natural product chemistry, researchers in TCM and pharmacology. We hope this article will inspire the development of novel formulas and molecular entities for the treatment of gout and GA.

Jianpi Qingre Tongluo Prescription (Huangqin Qingrechubi Capsule) alleviates inflammation and hypercoagulability by inhibiting the JAK2/STAT3 pathway via CircRNA 104633 downregulation in gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Gouty arthritis (GA) is characterized by intermittent inflammatory pain, which dramatically compromises the quality of life of patients. Huangqin Qingrechubi Capsule (HQC) is an empirical traditional Chinese medicine prescription used to treat GA for over 20 years, with favorable efficacy. However, little is known about the specific mechanism of action of HQC in GA treatment.

PURPOSE

This study probed the mechanism of action of HQC in the treatment of GA from anti-inflammatory and anticoagulation aspects.

METHODS

Initially, a retrospective clinical analysis was performed to observe the effects of HQC on inflammatory and coagulation indexes in GA patients. Subsequently, the expression of CircRNA 104633 and inflammatory and coagulation factors was detected in peripheral blood mononuclear cells (PBMCs) harvested from recruited GA patients before and after HQC treatment, followed by the analysis of the correlation between CircRNA 104633 and other indexes. The anti-inflammatory and anticoagulation mechanisms of HQC in GA treatment via CircRNA 104633 were further investigated through a co-culture model composed of GA-PBMCs and fibroblast-like synoviocytes (FLSs). Finally, a rat model of monosodium urate-induced GA was established for in vivo verification.

RESULTS

HQC reduced the levels of HCRP, ESR, and D-D in GA patients. In the PBMCs of GA patients, HQC decreased CircRNA 104633 expression, and CircRNA 104633 expression was closely related to inflammatory and coagulation indexes. CircRNA 104633 upregulation fostered inflammation and hypercoagulability in GA by activating the JAK2/STAT3 pathway, whilst HQC reversed the imbalance of inflammatory and coagulation factors by downregulating CircRNA 104633. Furthermore, HQC played anti-inflammatory and anticoagulant roles in GA rats by blocking the JAK2/STAT3 pathway.

CONCLUSION

HQC protects against inflammation and hypercoagulability in GA by inhibiting CircRNA 104633 and the JAK2/STAT3 pathway, which supports the development of therapeutic targets and drugs for GA.

Anemoside B4 targets NEK7 to inhibit NLRP3 inflammasome activation and alleviate MSU-induced acute gouty arthritis by modulating the NF-κB signaling pathway

BACKGROUND

Acute gouty arthritis is a metabolic disorder caused by monosodium urate (MSU) accumulation, leading to NLRP3 inflammasome activation and joint inflammation. Anemoside B4 (B4), a pentacyclic triterpenoid saponin, exerts significant anti-inflammatory effects. However, the precise molecular mechanisms underlying its therapeutic action, particularly its targeting of key components in NLRP3 inflammasome activation, remain unclear.

PURPOSE

The aim of this study was to elucidate the therapeutic mechanisms and target of B4 in treating MSU-induced macrophage pyroptosis and acute gouty arthritis, focusing specifically, on its interaction with NEK7, a critical regulator of NLRP3 inflammasome activation.

METHODS

Comprehensive in vitro and in vivo methods were employed to examine the effects and mechanisms of B4. In vitro analyses included Western blot, co-immunoprecipitation (Co-IP), and immunofluorescence assays to assess NLRP3 inflammasome components and NEK7-NLRP3 interactions. The binding of B4 to NEK7 was evaluated using molecular docking, surface plasmon resonance (SPR), cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS), NEK7 gene silencing, and site-specific amino acid mutation experiments. In vivo, MSU-induced acute gouty arthritis mouse models and NEK7 knockdown mouse models were used to demonstrate the therapeutic effects and specificity of B4.

RESULTS

This study provides the first evidence that B4 significantly inhibits MSU-induced inflammation and pyroptosis in macrophages by directly targeting NEK7 and disrupting the NEK7-NLRP3 complex, thereby reducing NLRP3 inflammasome activation. Additionally, B4 effectively suppressed MSU-induced ROS production, mitochondrial damage, and NF-κB activation. In vivo, B4 alleviated symptoms of acute gouty arthritis, reduced NLRP3 expression, and demonstrated specificity for NEK7 in NEK7 knockdown mouse models.

CONCLUSION

This study highlights B4 as an effective inhibitor of NLRP3 inflammasome activation by directly targeting NEK7, thereby mitigating inflammation and pyroptosis in acute gouty arthritis. These findings position B4 as a prospective therapeutic candidate for the management of acute gouty arthritis, providing insights into its molecular targets and mechanisms.

Developing an interpretable machine learning model for diagnosing gout using clinical and ultrasound features

OBJECTIVE

To develop a machine learning (ML) model using clinical data and ultrasound features for gout prediction, and apply SHapley Additive exPlanations (SHAP) for model interpretation.

METHODS

This study analyzed 609 patients' first metatarsophalangeal (MTP1) joint ultrasound data from two institutions. Institution 1 data (n = 571) were split into training cohort (TC) and internal testing cohort (ITC) (8:2 ratio), while Institution 2 data (n = 92) served as external testing cohort (ETC). Key predictors were selected using Random Forest (RF), Least Absolute Shrinkage and Selection Operator (LASSO), and Extreme Gradient Boosting (XGBoost) algorithms. Six ML models were evaluated using standard performance metrics, with SHAP analysis for model interpretation.

RESULTS

Five key predictors were identified: serum uric acid (SUA), deep learning (DL) model predictions, tophus, bone erosion, and double contour sign (DCs). The logistic regression (LR) model demonstrated optimal performance, achieving Area Under the Curve (AUC) values of 0.870 (95% CI: 0.820-0.920) in ITC and 0.854 (95% CI: 0.804-0.904) in ETC. The model showed good calibration with Brier scores of 0.138 and 0.159 in ITC and ETC, respectively.

CONCLUSION

This study developed an interpretable ML model for gout prediction and utilized SHAP to elucidate feature contributions, establishing a foundation for future applications in clinical decision support for gout diagnosis.

Integrative analysis reveals the multilateral inflammatory mechanisms of CD14 monocytes in gout

OBJECTIVES

Gout, prevalent inflammatory arthritis caused by urate crystal deposition, involves immune cell activation, yet the precise role of CD14 monocytes in initiating the inflammatory response is poorly understood. This study aimed to characterise the molecular and cellular landscape of CD14 monocytes in gout using single-cell transcriptomic analysis.

METHODS

Single-cell RNA sequencing was performed on peripheral blood mononuclear cells from 8 gout patients and 6 age- and sex-matched healthy controls. The findings were validated using publicly available datasets. Differential gene expression and pathway enrichment analyses were conducted to identify gout's key molecular regulators and cellular subclusters.

RESULTS

At the molecular level, we identified hypoxia-related pathways, including HIF1A, as key regulators of interleukin-1β production in CD14 monocytes in gout. We also observed significant downregulation of CLEC12A across all CD14 monocyte subclusters. At the cellular level, an S100Ahigh CD14 monocyte subcluster, characterized by high expression of S100A8/A9/A12 and linked to inflammatory and metabolic pathways, was found to drive NLRP3 and CLEC7A inflammasome activation, as well as prostaglandin secretion. In vitro stimulation with monosodium urate crystals revealed that the differentially expressed genes were enriched in S100Ahigh monocytes, highlighting the synergistic role of these pathways in driving gout inflammation. Additionally, gout genome-wide association study-prioritised genes underscored the role of fatty acid metabolism in inflammation, promoting prostaglandin secretion from S100Ahigh monocytes.

CONCLUSIONS

These findings provide new insights into the role of CD14 monocytes in gout pathogenesis, particularly the contribution of hypoxia and fatty acid metabolism pathways, and suggest potential therapeutic targets for precision medicine in gout treatment.

Plug-In Design of the Microneedle Electrode Array for Multi-Parameter Biochemical Sensing in Gouty Arthritis

Gouty arthritis is one of the most common forms of inflammatory arthritis and has brought a significant burden on patients and society. Current strategies for managing gout primarily focus on long-term urate-lowering therapy. With the rapid advancement of point-of-care testing (POCT) technology, continuous monitoring of gout-related biomarkers like uric acid (UA) or inflammatory cytokines can provide rapid and personalized diagnosis for gout management. In this study, a plug-in design of a microneedle electrode array (PIMNA) was developed and integrated into a multi-parameter sensing portable system in combination with embedded circuits and a mobile application. The system enabled real-time, in situ, and dynamic monitoring of biomarkers, including UA, reactive oxygen species (ROS), and pH at gouty joints. The multi-parameter monitoring system demonstrated a wide linear response range, excellent selectivity, stability, reproducibility, and reliable signal transmission performance. In vivo experiments demonstrated the real-time monitoring capability of PIMNA for UA, ROS, and pH, showing the potential to facilitate urate-lowering management and inflammation assessment. Prospectively, the system enables quantitative analysis of the complexity and diversity of gout, presenting promising applications in clinical practice. This work provides a unique strategy with potential for broader applications in gout management and arthritic disease treatment.

Impaired pulmonary function increases the risk of gout: evidence from a large cohort study in the UK Biobank

BACKGROUND

Pulmonary function is increasingly recognized as a key factor in metabolic diseases. However, its link to gout risk remains unclear. The study aimed to investigate the relationship between pulmonary function and the risk of developing gout and the underlying biological mechanisms.

METHODS

Our study included 420,002 participants with complete pulmonary function data from the UK Biobank. Logistic regression was used to evaluate gout prevalence among individuals with different pulmonary function statuses. Propensity score matching (PSM) created balanced groups, while Cox regression gauged the risk association between reduced lung capacity and gout compared with normal function. Mendelian randomization (MR) analysis was used to verify causal associations. Non-linear correlations were assessed with restricted cubic spline (RCS) analysis, and mediation analysis was used to explore the role of blood biomarkers. Mediation analyses were used to investigate the potential mediating role of biomarkers in the association.

RESULTS

Cross-sectional analysis revealed a higher prevalence of gout in individuals with preserved ratio of impaired spirometry (PRISm) of 6.31% and chronic obstructive pulmonary disease (COPD) of 6.26% than in those with normal pulmonary function (3.45%). After adjustment for covariates, both PRISm (odds ratio [OR] 1.24, 95% confidence interval [CI] 1.17-1.31) and COPD (OR 1.14, 95% CI 1.07-1.22) were significantly associated with gout. Longitudinal analysis confirmed that impaired pulmonary function significantly increased the risk of developing gout (hazard ratio [HR] 1.32, 95% CI 1.24-1.40). MR further revealed a potential causal effect of decreased pulmonary function on an increased risk of gout. Subgroup analysis revealed significant interactions between impaired pulmonary function and several factors, including body mass index (BMI), levels of physical activity, and diabetes status, in their associations with the risk of gout. RCS analysis showed a nonlinear relationship between pulmonary function indicators and gout incidence, characterized by an inverse S-shaped curve. Mediation analysis revealed that urate levels (49.1% mediation proportion), C-reactive protein (CRP) levels (6.62%), monocyte counts (1.33%), and neutrophil counts (4.85%) significantly mediated the relationship between pulmonary function and the risk of gout.

CONCLUSIONS

Our study revealed a significant association between impaired pulmonary function and an increased risk of developing gout. The association might be partially mediated by biomarkers including urate levels, inflammatory markers, and immune cell counts.

Mechanism of intestinal flora affecting SLC2A9 transport function to promote the formation of hyperuricemia

Objective

To investigate the structural characteristics of the intestinal flora in obese-hyperuricemic (HUA-W) patients and the mechanisms by which they promote the formation of hyperuricemia.

Methods

120 human fecal samples (60 cases in HC, 30 cases in HUA-N, and 30 cases in HUA-W) and 40 cases in the colonic tissues (20 cases in HC, 10 cases in HUA-N, and 10 cases in HUA-W) were collected. The intestinal flora of faeces was detected by 16s rRNA method; and the expression of SLC2A9 on human colon tissues was detected by RT-qPCR method and immunofluorescence method. 40 obese-hyperuricemia rat models were established (10 rats in Model, 10 rats in HC-FT, 10 rats in HUA-N-FT, and 10 rats in HUA-W-FT), and 10 rats were set up in Control; and the level of uric acid in rat serum, the levels of xanthine oxidase (XOD) activity and uric acid in intestinal fluid were examined. SLC2A9+ Caco-2 cells were produced to simulate the Transwell uric acid transport model, and the Caco-2 cells and SLC2A9+ Caco-2 cells were grown in five different culture media (Blank, Germ-free, HC-germ, HUA-N-germ and HUA-W-germ), and the uric acid levels in the upper and lower layers of the chambers were detected.

Results

The HUA-W intestinal flora showed significant specificity, with a decrease in Bacteroidota and Bacteroidia and an increase in Escherichia and Ruminococcus. There were no significant differences in the fluorescence intensity of the SLC2A9 protein and the SLC2A9 mRNA levels in the colon tissues of the HUA-N and HUA-W (P = 0.447, P = 0.152, P = 0.4799 and P = 0.965, respectively). In rat animal experiments, uric acid levels were significantly higher (P < 0.05) and XOD activity was significantly higher (P < 0.05) in intestinal fluid of HUA-W-FT. In Transwell experiments with SLC2A9+ Caco-2 cells, uric acid levels were increased in the upper compartment and decreased in the lower compartment of HUA-W-germ.

Conclusion

HUA-W intestinal flora may increase XOD activity in the intestinal tract and improve the ability of uric acid transporter protein SLC2A9 to reabsorb uric acid, providing a new theoretical basis for the pathogenesis of hyperuricemia.

Recent Progress and Future Perspectives on Anti-Hyperuricemic Agents

Increased biosynthesis or underexcretion of uric acid (UA or urate) in the body ultimately leads to the development of hyperuricemia. Epidemiological studies indicate that hyperuricemia is closely associated with the occurrence of various diseases such as gout and cardiovascular diseases. Currently, the first-line therapeutic medications used to reduce UA levels primarily include xanthine oxidase (XO) inhibitors, which limit UA production, and urate transporter 1 (URAT1) inhibitors, which decrease urate reabsorption and enhance urate excretion. Despite significant progress in urate-lowering therapies, long-term use of these drugs can cause hepatorenal toxicity as well as cardiovascular complications. Therefore, there is an urgent need for novel anti-hyperuricemic agents with better efficacy and lower toxicity. This perspective mainly focuses on the current research progress and design strategy of anti-hyperuricemic agents, particularly those targeting XO and URAT1. It is our hope that this perspective will provide insights into the challenges and opportunities for anti-hyperuricemic drug discovery.

Mesenchymal stem cells and their extracellular vesicles in bone and joint diseases: targeting the NLRP3 inflammasome

The nucleotide-binding oligomerization domain-like-receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a cytosolic multi-subunit protein complex, and recent studies have demonstrated the vital role of the NLRP3 inflammasome in the pathological and physiological conditions, which cleaves gasdermin D to induce inflammatory cell death called pyroptosis and mediates the release of interleukin-1 beta and interleukin-18 in response to microbial infection or cellular injury. Over-activation of the NLRP3 inflammasome is associated with the pathogenesis of many disorders affecting bone and joints, including gouty arthritis, osteoarthritis, rheumatoid arthritis, osteoporosis, and periodontitis. Moreover, mesenchymal stem cells (MSCs) have been discovered to facilitate the inhibition of NLRP3 and maybe ideal for treating bone and joint diseases. In this review, we implicate the structure and activation of the NLRP3 inflammasome along with the detail on the involvement of NLRP3 inflammasome in bone and joint diseases pathology. In addition, we focused on MSCs and MSC-extracellular vesicles targeting NLRP3 inflammasomes in bone and joint diseases. Finally, the existing problems and future direction are also discussed.

Mechanism of Reactive Oxygen Species-Guided Immune Responses in Gouty Arthritis and Potential Therapeutic Targets

Gouty arthritis (GA) is an inflammatory disease caused by monosodium urate (MSU) crystals deposited in the joint tissues causing severe pain. The disease can recur frequently and tends to form tophus in the joints. Current therapeutic drugs for the acute phase of GA have many side effects and limitations, are unable to prevent recurrent GA attacks and tophus formation, and overall efficacy is unsatisfactory. Therefore, we need to advance research on the microscopic mechanism of GA and seek safer and more effective drugs through relevant targets to block the GA disease process. Current research shows that the pathogenesis of GA is closely related to NLRP3 inflammation, oxidative stress, MAPK, NET, autophagy, and Ferroptosis. However, after synthesizing and sorting out the above mechanisms, it is found that the presence of ROS is throughout almost the entire spectrum of micro-mechanisms of the gout disease process, which combines multiple immune responses to form a large network diagram of complex and tight connections involved in the GA disease process. Current studies have shown that inflammation, oxidative stress, cell necrosis, and pathological signs of GA in GA joint tissues can be effectively suppressed by modulating ROS network-related targets. In this article, on the one hand, we investigated the generative mechanism of ROS network generation and its association with GA. On the other hand, we explored the potential of related targets for the treatment of gout and the prevention of tophus formation, which can provide effective reference ideas for the development of highly effective drugs for the treatment of GA.

Astilbin inhibited neutrophil extracellular traps in gouty arthritis through suppression of purinergic P2Y6 receptor

BACKGROUND

Gouty arthritis (GA), a common inflammatory condition triggered by monosodium urate crystal accumulation, often necessitates safer treatment alternatives due to the limitations of current therapies. Astilbin, a flavonoid from Smilax glabra Roxb, has demonstrated potential in traditional Chinese medicine for its anti-inflammatory properties. However, the anti-GA effect and its underlying mechanism have not been fully elucidated.

PURPOSE

This study aimed to investigate the therapeutic potential of astilbin in GA, focusing on its effects on neutrophil extracellular traps (NETs), as well as the potential molecular target of GA both in vitro and in vivo.

STUDY DESIGN

Firstly, astilbin inhibited the citrullinated histone H3 (Cit h3) protein levels and reduced the NETs formation in neutrophils stimulated by monosodium urate (MSU). Secondly, we wondered the effect of astilbin on migration of neutrophils and dimethyl-sulfoxide (DMSO)-differentiated HL-60 (dHL-60) cells under the stimulation of MSU. Then, the effect of astilbin on suppressing NETs through purinergic P2Y6 receptor (P2Y6R) and Interlukin-8 (IL-8)/ CXC chemokine receptor 2 (CXCR2) pathway was investigated. Also, the relationship between P2Y6R and IL-8/CXCR2 was explored in dHL-60 cells under stimulation of MSU. Finally, we testified the effect of astilbin on reducing NETs in GA through suppressing P2Y6R and then down-regulating IL-8/CXCR2 pathway.

METHODS

MSU was used to induce NETs in neutrophils and dHL-60 cells. Real-time formation of NETs and migration of neutrophils were monitored by cell living imaging with or without MSU. Then, the effect of astilbin on NETs formation, P2Y6R and IL-8/CXCR2 pathway were detected by immunofluorescence (IF) and western blotting. P2Y6R knockdown dHL-60 cells were established by small interfering RNA to investigate the association between P2Y6R and IL-8/CXCR2 pathway. Also, plasmid of P2Y6R was used to overexpress P2Y6R in dHL-60 cells, which was employed to explore the role of P2Y6R in astilbin inhibiting NETs. Within the conditions of knockdown and overexpression of P2Y6R, migration and NETs formation were assessed by transmigration assay and IF staining, respectively. In vivo, MSU-induced GA mice model was established to assess the effect of astilbin on inflammation by haematoxylin-eosin and ELISA. Additionally, the effects of astilbin on neutrophils infiltration, NETs, P2Y6R and IL-8/CXCR2 pathway were analyzed by IF, ELISA, immunohistochemistry (IHC) and western blotting.

RESULTS

Under MSU stimulation, astilbin significantly suppressed the level of Cit h3 and NETs formation including the fluorescent expressions of Cit h3, neutrophils elastase, myeloperoxidase, and intra/extracellular DNA. Also, results showed that MSU caused NETs release in neutrophils as well as a trend towards recruitment of dHL-60 cells to MSU. Astilbin could markedly decrease expressions of P2Y6R and IL-8/CXCR2 pathway which were upregulated by MSU. By silencing P2Y6R, the expression of IL-8/CXCR2 pathway and migration of dHL-60 cells were inhibited, leading to the suppression of NETs. These findings indicated the upstream role of P2Y6R in the IL-8/CXCR2 pathway. Moreover, overexpression of P2Y6R was evidently inhibited by astilbin, causing a downregulation in IL-8/CXCR2 pathway, migration of dHL-60 cells and NETs formation. These results emphasized that astilbin inhibited the IL-8/CXCR2 pathway primarily through P2Y6R. In vivo, astilbin administration led to marked reductions in ankle swelling, inflammatory infiltration as well as neutrophils infiltration. Expressions of P2Y6R and IL-8/CXCR2 pathway were evidently decreased by astilbin and P2Y6R inhibitor MRS2578 either alone or in combination. Also, astilbin and MRS2578 showed notable effect on reducing MSU-induced NETs formation and IL-8/CXCR2 pathway whether used alone or in combination, parallelly demonstrating that astilbin decreased NETs formation mainly through P2Y6R.

CONCLUSION

This study revealed that astilbin suppressed NETs formation via downregulating P2Y6R and subsequently the IL-8/CXCR2 pathway, which evidently mitigated GA induced by MSU. It also highlighted the potential of astilbin as a promising natural therapeutic for GA.

Spatiotemporal Observation of Monosodium Urate Crystals Deposition in Synovial Organoids Using Label-Free Stimulated Raman Scattering

Gout, a common form of arthritis, is characterized by the deposition of monosodium urate (MSU) crystals in joints. MSU deposition in synovial tissues would initiate arthritis flares and recurrence, causing irreversible joint damage. However, the dynamic deposition of MSU crystals in tissues lacks experimental observation. In this study, we used chemical-specific, label-free stimulated Raman scattering (SRS) microscopy to investigate the spatiotemporal deposition and morphological characteristics of MSU crystals in human synovial organoids. Our findings revealed a critical 12-h window for MSU deposition in the lining layer of gouty synovium. Moreover, distinctive inflammatory reactions of the lining and sublining synovial layers in gout using SRS microscopy were further verified by immunofluorescence. Importantly, we identified a crucial proinflammatory role of sublining fibroblast-like synoviocytes, indicating a need for targeted medication treatment on these cells. Our work contributes to the fundamental understanding of MSU-based diseases and offers valuable insights for the future development of targeted gout therapies.

Interpretable machine learning framework to predict gout associated with dietary fiber and triglyceride-glucose index

BACKGROUND

Gout prediction is essential for the development of individualized prevention and treatment plans. Our objective was to develop an efficient and interpretable machine learning (ML) model using the SHapley Additive exPlanation (SHAP) to link dietary fiber and triglyceride-glucose (TyG) index to predict gout.

METHODS

Using datasets from the National Health and Nutrition Examination Survey (NHANES) (2005-2018) population to study dietary fiber, the TyG index was used to predict gout. After evaluating the performance of six ML models and selecting the Light Gradient Boosting Machine (LGBM) as the optimal algorithm, we interpret the LGBM model for predicting gout using SHAP and reveal the decision-making process of the model.

RESULTS

An initial survey of 70,190 participants was conducted, and after a gradual exclusion process, 12,645 cases were finally included in the study. Selection of the best performing LGBM model for prediction of gout associated with dietary fiber and TyG index (Area under the ROC curve (AUC): 0.823, 95% confidence interval (CI): 0.798-0.848, Accuracy: 95.3%, Brier score: 0.077). The feature importance of SHAP values indicated that age was the most important feature affecting the model output, followed by uric acid (UA). The SHAP values showed that lower dietary fiber values had a more pronounced effect on the positive prediction of the model, while higher values of the TyG index had a more pronounced effect on the positive prediction of the model.

CONCLUSION

The interpretable LGBM model associated with dietary fiber and TyG index showed high accuracy, efficiency, and robustness in predicting gout. Increasing dietary fiber intake and lowering the TyG index are beneficial in reducing the potential risk of gout.

Creating machine learning models that interpretably link systemic inflammatory index, sex steroid hormones, and dietary antioxidants to identify gout using the SHAP (SHapley Additive exPlanations) method

Background

The relationship between systemic inflammatory index (SII), sex steroid hormones, dietary antioxidants (DA), and gout has not been determined. We aim to develop a reliable and interpretable machine learning (ML) model that links SII, sex steroid hormones, and DA to gout identification.

Methods

The dataset we used to study the relationship between SII, sex steroid hormones, DA, and gout was from the National Health and Nutrition Examination Survey (NHANES). Six ML models were developed to identify gout by SII, sex steroid hormones, and DA. The seven performance discriminative features of each model were summarized, and the eXtreme Gradient Boosting (XGBoost) model with the best overall performance was selected to identify gout. We used the SHapley Additive exPlanation (SHAP) method to explain the XGBoost model and its decision-making process.

Results

An initial survey of 20,146 participants resulted in 8,550 being included in the study. Selecting the best performing XGBoost model associated with SII, sex steroid hormones, and DA to identify gout (male: AUC: 0.795, 95% CI: 0.746- 0.843, accuracy: 98.7%; female: AUC: 0.822, 95% CI: 0.754- 0.883, accuracy: 99.2%). In the male group, The SHAP values showed that the lower feature values of lutein + zeaxanthin (LZ), vitamin C (VitC), lycopene, zinc, total testosterone (TT), vitamin E (VitE), and vitamin A (VitA), the greater the positive effect on the model output. In the female group, SHAP values showed that lower feature values of E2, zinc, lycopene, LZ, TT, and selenium had a greater positive effect on model output.

Conclusion

The interpretable XGBoost model demonstrated accuracy, efficiency, and robustness in identifying associations between SII, sex steroid hormones, DA, and gout in participants. Decreased TT in males and decreased E2 in females may be associated with gout, and increased DA intake and decreased SII may reduce the potential risk of gout.

Modulation of the dissolution with ASP from a supersaturated solution on a bionic platform for gout pathology crystals

The core to the treatment of gout is the elimination of pathologic crystal, monosodium urate monohydrate (MSUM). The primary treatment available is to gradually dissolve the "culprit crystals" by lowering the blood uric acid concentration with medications, which often takes a long time and in severe cases must still be treated surgically. Herein, we developed a dynamic bionic platform based on a hydrogel composite membrane (HCM) to screen the direct facilitated solubilization of MSUM crystals by small organic molecules in bionic saturated, or even supersaturated, solutions. The customized and biologically safe (NAGA/PEGDA/NIPAM) HCM, which is consistent with the main amino acid composition of articular cartilage, well mimics the entire process of organic molecules leading to the dissolution of MSUM crystals in the joint system. With the verifications of this platform, it is shown that l-aspartic acid (ASP) significantly promotes the dissolution of MSUM crystals not only in saturated but also in supersaturated solutions. Furthermore, a novel mechanism called "crane effect" was used to explain this "dissolution effect" of ASP on MSUM, which stems from the ability of ASP to lock onto the surface of MSUM crystals through hydrogen bonding by virtue of its two carboxyl groups, and simultaneously its amino group lifts the uric acid molecules from the surface of MSUM crystals by virtue of interactions of hydrogen bonding. The results of bulk crystallization, scanning electron microscopy (SEM), powder X-diffraction (PXRD), and density-functional theory (DFT) studies are quantitatively consistent with this hypothetical "crane effect" mechanism. Hence, this HCM-based functional platform could provide entirely novel ideas and methods for drug design and screening for the treatment of pathological crystal diseases of gout.

An Updated Review For Hyperuricemia and Gout Management; Special Focus on the Available Drug Delivery Systems and Clinical Trials

BACKGROUND

Hyperuricemia belongs to metabolic syndromes where increased uric acid levels are identified in the blood serum. Such a syndrome could be responsible for kidney stone formation, gout, hypertension, and chronic kidney diseases. It has been reported that cardiovascular risks have been linked with hyperuricemia. Gout is of the most frequent manifestations due to hyperuricemia; its management involves various pharmacological available options and dietary changes. Throughout the literature, various dosage forms are studied as alternative options to the present drug delivery systems.

OBJECTIVE

To update and summarize the current information for gout and hyperuricemia management.

METHODS

Authors have performed a thorough literature research from 2010-2023 using keywords such as hyperuricemia, gout, diagnosis, guidelines, drug delivery and clinical trials. The databases used were PubMed, ScienceDirect. According to our inclusion criteria, all studies which include the previous terms, as well as drugs or other molecules that can be applied for gout and/or hyperuricemia management, were added.

RESULTS

In this article, authors have summarized the pathogenesis, diagnosis and updated guidelines for gout and hyperuricemia management. Moreover, the authors have reviewed and discussed current drug delivery systems found in the literature, including drugs targeting the above disorders. Finally, the available clinical trials assessing the efficacy of newer drugs or combinations of the past ones, are being discussed.

CONCLUSION

The available drugs and dosage forms are limited, and therefore, scientific society should focus on the development of more efficient drug delivery systems for hyperuricemia and gout management.

Emodin, a Natural Anthraquinone, Increases Uric Acid Excretion in Rats with Potassium Oxonate-Induced Hyperuricemia

The treatment of hyperuricemia and gout is mostly based on lowering serum uric acid levels using drugs, such as allopurinol, or increasing urinary excretion of uric acid. However, some patients still experience adverse reactions to allopurinol and turn to Chinese medicine as an alternative. Therefore, it is crucial to design a preclinical study to obtain more convincing data on the treatment of hyperuricemia and gout with Chinese medicine. This study aimed to explore the therapeutic effect of emodin, a Chinese herbal extract, in a rat model of hyperuricemia and gout. In this study, we used 36 Sprague-Dawley rats, which were randomly divided into six groups for experimentation. Hyperuricemia was induced in rats by intraperitoneal injections of potassium oxonate. The efficacy of emodin in reducing serum uric acid levels was demonstrated by comparing the positive control group with groups treated with three different concentrations of emodin. The inflammatory profiles, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α levels, were unaffected by emodin treatment. In the experimental results, it was observed that the serum uric acid concentration in the vehicle control group was 1.80 ± 1.14, while the concentrations in the moderate and high concentration emodin groups were 1.18 ± 0.23 and 1.12 ± 0.57, resulting in no significant difference in uric acid concentration between these treatment groups and the control group, indicating that emodin has a therapeutic effect on hyperuricemia. The increase in the fractional excretion of uric acid (FEUA) demonstrated that emodin promoted urinary uric acid excretion without significantly affecting the inflammatory profile. Thus, emodin reduced the serum uric acid concentration to achieve effective treatment of hyperuricemia and gout by increasing urinary excretion. These results were supported by the measured serum uric acid and FEUA levels. Our data have potential implications for the treatment of gout and other types of hyperuricemia in clinical practice.