The anatomical pathology of gout: a systematic literature review

Study on the Mechanism of Galangin on Hyperuricemic Nephropathy Based on Metabolomics and Network Pharmacology

Galangin (GAL), a flavonol found in Alpinia officinarum and propolis, is a promising functional food. This study investigated the therapeutic effects and mechanisms of GAL in mice with hyperuricemic nephropathy (HN) by focusing on renal metabolomics and network pharmacology. In this study, we conducted untargeted metabolomic analysis and network pharmacology prediction. Subsequently, a compound-reaction-enzyme-gene network was constructed based on the results of metabolomics and network pharmacology to elucidate potential connections. The results demonstrated that GAL can improve renal interstitial fibrosis and inflammatory infiltration and reduce serum levels of uric acid (UA), urea nitrogen (UREA), and creatinine (CREA). Metabolome analysis indicated that GAL affected thiamine, pyrimidine, nicotinate, nicotinamide, pyruvate, glyoxylate, and dicarboxylate metabolism. Network pharmacology and experimental results showed that GAL reduced the key target expression of the tumor protein P53 (TP53), tumor necrosis factor (TNF), signal transducer and activator of transcription 3 (STAT3), heat shock protein 90 alpha family class A member 1 (HSP90aa1), albumin (ALB), and caspase-3 (CASP3). GAL also downregulated the expression of Janus kinase 2 (JAK2), phospho-JAK2 (P-JAK2), and phospho-STAT3 (P-STAT3). Furthermore, a joint analysis of the metabolome and network pharmacology showed that GAL can reverse HN through amino acid metabolism, nucleotide metabolism, energy metabolism, and endocrine system pathways. GAL can alleviate HN effectively and might play synergistic therapeutic roles through regulating metabolic profiles and the JAK2/STAT3 signaling pathway.

A dynamic study on serum biomarkers and kidney injury in a gosling model of hyperuricemia

Hyperuricemia, a metabolic disorder characterized by elevated serum uric acid levels, poses significant challenges to poultry health and productivity. This study aimed to establish a hyperuricemia model in goslings through a multi-factorial induction approach using a high-purine, high-protein, and high-calcium diet, to investigate its dynamic progression, serological markers, and renal pathology. A total of 160 male Sanhua goslings were randomly assigned to control and model groups and fed either a basal diet or a high-purine, high-protein, and high-calcium diet for 18 days. Key findings revealed significant elevations in serum uric acid, creatinine, and urea nitrogen levels in the model group from day 5 onward, peaking on day 13 (p < 0.01). Activities of xanthine oxidase and adenosine deaminase were consistently higher in the model group, indicating enhanced purine metabolism and oxidative stress. Histopathological analysis showed progressive renal damage, including tubular degeneration, interstitial fibrosis, and glomerular injury, becoming evident by day 7 and severe by day 13. Ultrastructural examination further revealed mitochondrial dysfunction, podocyte effacement, and basement membrane disruption in the model group. Behavioral abnormalities, such as reduced mobility and the "shrinking neck" phenomenon, were observed from day 9, reflecting systemic disease severity. The dynamic expression of fibrosis-related markers, including Col-1, Col-3, and α-SMA, demonstrated the progression of renal fibrosis and extracellular matrix remodeling. These findings identify biomarkers for hyperuricemia progression and suggest potential therapeutic targets. This study establishes a comprehensive framework for understanding hyperuricemia-associated renal pathology and lays the groundwork for developing strategies to mitigate its impact on poultry health and productivity.

Unraveling the impact of miRNAs on gouty arthritis: diagnostic significance and therapeutic opportunities

Gouty arthritis is a prevalent inflammatory illness. Gout attacks begin when there is an imbalance in the body's uric acid metabolism, which leads to urate buildup and the development of the ailment. A family of conserved, short non-coding RNAs known as microRNAs (miRNAs) can regulate post-transcriptional protein synthesis by attaching to the 3' untranslated region (UTR) of messenger RNA (mRNA). An increasing amount of research is pointing to miRNAs as potential players in several inflammatory diseases, including gouty arthritis. miRNAs may influence the progression of the disease by regulating immune function and inflammatory responses. This review mainly focused on miRNAs and how they contribute to gouty arthritis. It also looked at how miRNAs could be used as diagnostic, prognostic, and potential therapeutic targets.

Efficacy and safety of Chinese herbal compound in the treatment of acute gouty arthritis: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The present study aimed to comprehensively assess the efficacy and safety of Chinese herbal compounds in the management of acute gouty arthritis (AGA).

MATERIALS AND METHODS

A systematic search was performed across multiple databases, including PubMed, The Cochrane Library, Embase, Web of Science, CBM, CNKI, VIP, and Wanfang, from their inception until December 1, 2024, to identify relevant randomized controlled trials (RCTs) involving Chinese herbal compounds for AGA. Two independent researchers were responsible for the retrieved literature screening, data extraction, and quality evaluation. A meta-analysis of RCTs that fulfill the inclusion criteria will be executed utilizing Stata 14.0 software. The quality of the outcomes will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

A total of 28 studies, encompassing 2100 participants, were included in the analysis. The meta-analysis showed that compared with conventional Western medicine, Chinese herbal compounds significantly enhance the overall efficacy of AGA treatment (RR = 1.11, 95 %CI (1.05, 1.16), P < 0.00001; Level of evidence: very low). It also demonstrated improvements in the Visual Analogue Scale (VAS) (SMD = -1.46, 95 %CI(-2.17, -0.75), P < 0.00001; Level of evidence: very low), serum uric acid levels (SMD = -0.67, 95 %CI (-1.00, -0.33), P < 0.00001; Level of evidence: very low), blood sedimentation levels (SMD = -0.71, 95 %CI (-1.08, -0.33), P < 0.00001; Level of evidence: very low), C-reactive protein (CRP) levels (SMD = 0.89, 95 %CI(-1.33, -0.45), P < 0.00001; Level of evidence: very low), and the traditional Chinese medicine syndrome score(SMD = -0.93, 95 %CI (-1.37, -0.49), P < 0.00001; Level of evidence: very low). Additionally, a reduced incidence of adverse effects was noted (RR = 0.26, 95 %CI (0.18, 0.39), P < 0.00001; Level of evidence: moderate). Subgroup analysis revealed that regardless of whether the treatment duration was less than or more than 1 week, Chinese herbal compounds were effective in improving the total effective rate of AGA treatment, VAS scores, serum uric acid levels, blood sedimentation levels, CRP levels, and Traditional Chinese medicine symptom scores, while simultaneously decreasing the occurrence of adverse reactions.

CONCLUSION

Chinese herbal compounds demonstrated superior efficacy and safety compared to conventional Western medicine in treating AGA. However, further validation through multicenter, high-quality RCTs is warranted to strengthen this conclusion.

The Design of a Randomized Controlled Active Comparator Strategy Trial for Gout: Treat to Target Serum Urate Versus Treat to Avoid Symptoms

OBJECTIVE

Controversy persists regarding the optimal management of gout in routine primary care. There is a lack of clarity on whether treating to a target serum urate (TTT-SU) versus treating to avoid symptoms (TTASx) is more effective.

METHODS

We designed a randomized controlled comparative effectiveness trial aimed at patients in primary care who have known gout, have elevated SU levels, and had at least one flare in the previous 12 months. The trial was designed to be pragmatic and incorporated structured input from primary care physicians, rheumatologists, and patients. The TTASx strategy group will receive weeklong courses of typical therapies for gout flares, such as colchicine, naproxen, or an oral glucocorticoid. The TTT-SU strategy group will receive urate-lowering therapy (primarily allopurinol) with dose titration to maintain an SU level <6 mg/dL, colchicine (or naproxen) prophylaxis for the first six months of urate-lowering therapy, and access to the same flare therapies as the TTASx group. Two clinicians (nurses or physicians) per site will be trained in each strategy to manage the patients in each arm without contamination. Gout flares are the primary outcome and are assessed every two weeks by trained study staff masked to treatment assignment using a validated questionnaire. The secondary outcome is quality of life. Blood pressure control, kidney function, glycemic control, and coronary atherosclerosis are exploratory secondary outcomes.

RESULTS

Several sites have started prescreening using automated search strategies in their patients' electronic health records. Of the first 1,381 patients found in primary care practices with a history of gout, 691 patients (50%) passed prescreening checks. These potentially eligible participants have a median age of 67 years, 85% are men, median SU levels are 7.2 mg/dL, and 18% are taking low dosages of allopurinol. These patients have been targeted for recruitment efforts that are underway now.

CONCLUSION

This randomized controlled active comparator strategy trial will answer a key question in the treatment of patients with gout in primary care: the comparative effectiveness of TTT-SU versus TTASx in gout. Secondary and exploratory outcomes will add important information regarding the broader extra-articular and quality-of-life effects of lowering SU levels.

Abdominal Abscess as a Rare Manifestation of Gout

Gout is a common inflammatory arthritis in adults. Elevated levels of uric acid lead to the formation of monosodium urate crystals and their deposition in joints, and rarely, other parts of the body. The tissues most frequently involved are synovium, bone, cartilage, skin, tendon, ligament, and kidney. Here, we report an unusual presentation of gout manifesting as an abdominal abscess. A 60-year-old man with a history of opioid abuse, hypertension, and knee gouty arthritis presented to the emergency department with severe right knee pain. During hospitalization, he complained of pain in the left lower abdominal quadrant and developed coffee-ground emesis. Computed tomography showed pneumoperitoneum. The patient underwent laparotomy and was found to have gastric perforation and a large abdominal abscess. Drainage of the abscess revealed necrotic and hemorrhagic fragments of omentum. Microscopic examination showed adipose tissue with fat necrosis, acute inflammation, and fungal hyphae. Eosinophilic, amorphous deposits of polarizable needle-shaped crystals were observed in all sections, indicating the presence of monosodium urate crystals. The combined characteristics suggested intra-abdominal gout with concurrent fungal infection resulting from gastric perforation. This presentation is very rare. Only one occurrence of intra-abdominal gout mimicking a pelvic abscess has been reported in the literature.

Untargeted metabolomics analysis of the urinary metabolic signature of acute and chronic gout

BACKGROUND

Gout is a common kind of inflammatory arthritis with metabolic disorders. However, the detailed pathogenesis of gout is complex and not fully clear. We investigated the urine metabolic profiling of gout patients by ultra-performance liquid chromatograph quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS).

METHOD

Urine metabolites were extracted from 26 acute gout patients, 31 chronic gout patients, and 32 healthy controls. Metabolite extracts were analyzed by UPLC-Q-TOF-MS for untargeted metabolomics. The peak area of creatinine was used to correct the content variations of urine samples for the semi-quantitative analysis. The value of variable importance in the projection (VIP) was obtained through the orthogonal partial least squares-discrimination analysis (OPLS-DA), and several differential metabolites were screened out.

RESULTS

The potential metabolic markers of gout in different stages were found based on the t-test. Finally, 18 different metabolites were identified through Human Metabolome Database (HMDB) and Targeted-MS/MS. The receiver operating characteristic (ROC) curve results revealed that all the screened biomarkers exerted high accuracy and diagnostic value. Pathway analysis indicated that the significantly different metabolites were mainly involved in purine metabolism and amino acid metabolism.

CONCLUSION

The identified potential biomarkers are mainly involved in purine metabolism and amino acid metabolism, which leads us to further explore the pathogenesis of gout. This will lead us to further explore the pathogenesis of gout and provide the basis and ideas for the prevention and treatment of gout.

Surgical Management of Tophaceous Gout in the Upper Limb

PURPOSE

Gouty tophi are a clinical manifestation of hyperuricemia in advanced stages. They can produce pain, functional limitation, and severe deformities. Patients with severe symptoms require short-term symptomatic solutions that standard medical management is not able to provide. The objective of this study was to present the results obtained with the surgical management of tophaceous gout in the upper limb, as well as present a detailed characterization of the disease in the upper limb.

METHODS

Databases of the hand surgery service of a quaternary care hospital were reviewed to identify patients aged >18 years old undergoing tophi resection in the upper limbs between 2014 and 2020. Medical history records were reviewed retrospectively, and the relevant data were extracted to establish demographic profile, clinical presentation, anatomic distribution, postoperative outcomes, and additional procedures required.

RESULTS

The most frequent symptom was pain (83%), followed by limited range of motion (56%), deformity (50%), and daily living/occupational activity limitation (28%). The main indications for surgical management were the presence of deformity, pain, and/or limited range of motion. The most frequently affected anatomic sites were the metacarpophalangeal joints, followed by the elbows, proximal interphalangeal joints, and proximal phalanges. The postoperative complication rate was 28%. The most common complications were operative site infections and wound dehiscence. Decreased pain was associated with surgical resection. Additional procedures, such as extensor tenorrhaphy and local flaps, were required in 47.2% of patients.

CONCLUSION

Surgical resection of tophi can decrease pain. Although surgery is associated with a high rate of complications, most are minor.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Functional Food Potential of Chrysanthemum morifolium, Perilla frutescens, and Sophora japonica in Managing Hyperuricemia through Dual Enzyme Inhibition

Amid growing concerns regarding gout and hyperuricemia associated with high-protein and purine-rich diets, the need for effective prevention and management strategies with minimal side effects has become increasingly critical. This study evaluates the potential of three commonly consumed plant-based functional foods, Chrysanthemum morifolium, Perilla frutescens, and Sophora japonica, inhibiting xanthine oxidase (XO) and adenosine deaminase (ADA), key enzymes in uric acid metabolism. Results from hyperuricemia model mice indicate that this blend significantly reduces serum uric acid levels, mirroring the efficacy of conventional prevention and management strategies such as allopurinol but with fewer adverse effects. Liquid chromatography-mass spectrometry (LC-MS) analysis confirms that flavonoids are the primary bioactive agents, exhibiting a strong affinity for XO. These findings highlight the viability of integrating plant-based functional foods into comprehensive gout management strategies, underscoring their role in enhancing patient health through dietary innovation.

Investigating the involvement of the NLRP3/ASC/caspase-1 and NF-κb/MAPK pathways in the pathogenesis of gouty arthritis: Insights from irradiated and non-irradiated Trifolium alexandrium L. extracts and some metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

Trifolium alexandrinum L. (TA), has traditionally been used in folk medicine for its anti-inflammatory properties against hyperuricemia and gout. However, the specific mechanisms of action of TA have not been thoroughly studied.

AIM OF THE WORK

This study aimed to evaluate the protective effects of irradiated (TR25) and non-irradiated (TR0) Trifolium alexandrinum L. aqueous extract (TAAE), along with two isolated compounds, caffeine (CAF) and saponin (SAP), in a rat model of acute gouty arthritis (GA).

MATERIALS AND METHODS

The GA model was established by injecting a monosodium urate (MSU) suspension into the knee joint. Synovial tissue pathology was assessed, and levels of TNF-α, IL-6, IL-1β, NF-κB, mTOR, AKT1, PI3K, NLRP3, and ASC were measured by ELISA. mRNA expression of ERK1, JNK, and p-38 MAPK was detected using qRT-PCR, and Caspase-1 protein expression was assessed by immunohistochemical analysis. Knee swelling, uric acid levels, liver and kidney function, and oxidative stress markers were also evaluated.

RESULTS

TAAE analysis identified 170 compounds, with 73 successfully identified using LC-HR-MS/MS, including caffeine citrate and theasapogenol B glycoside as the main constituents. The studied materials demonstrated significant protective effects against GA. TR25 administration significantly mitigated knee joint circumference compared to other treatments. It demonstrated potential in alleviating hyperuricemia, renal and hepatic impairments induced by MSU crystals. TR25 also alleviated oxidative stress and reduced levels of IL1β, IL-6, TNF-α, and NF-κB. Weak Caspase-1 immune-positive staining was observed in the TR25 group. TR25 decreased NLRP3 and ASC expression, reducing inflammatory cytokine levels in GA. It effectively inhibited the PI3K, AKT, and mTOR signaling pathways, promoting autophagy. Additionally, TR25 suppressed ERK1, JNK, and p-38 MAPK gene expression in synovial tissue. These effects were attributed to various components in TAAE, such as flavonoids, phenolic acids, tannins, alkaloids, and triterpenes.

CONCLUSION

Importantly, irradiation (25 KGy) enhanced the antioxidant effects and phtchemical contents of TAAE. Additionally, TR0, TR25, CAF, and SAP exhibited promising protective effects against GA, suggesting their therapeutic potential for managing this condition. These effects were likely mediated through modulation of the NLRP3/ASC/Caspase-1 and ERK/JNK/p-38 MAPK signaling pathways, as well as regulation of the PI3K/AKT/mTOR pathway. Further research is warranted to fully elucidate the underlying mechanisms and optimize their clinical applications.

Associations of Changes in Knee Hyaline Cartilage Composition Measured With Dual-Energy Computed Tomography in Gout, Aging and Osteoarthritis

OBJECTIVE

To characterize dual-energy computed tomography (DECT) changes depicting hyaline cartilage changes in gout patients with and without osteoarthritis (OA) and in comparators without gout.

DESIGN

Patients with suspected crystal-associated arthropathy were enrolled and underwent bilateral DECT scans of the knees. Standardized regions of interest were defined in the femorotibial hyaline cartilage. Five DECT parameters were obtained: CT numbers in Hounsfield units (HU) at 80 and 140 kV, the electron density (Rho), the effective atomic number (Zeff), and the dual-energy index (DEI). Zones were compared between patients with gout, with and without knee OA, and between patients with gout and comparators without gout, after adjustment for confounders.

RESULTS

A total of 113 patients with gout (mean age 63.5 ± 14.3 years) and 15 comparators without gout (mean age 75.8 ± 11.5 years) were included, n = 65 (51%) had knee OA, and 466 zones of hyaline cartilage were analyzed. Older age was associated with lower attenuations at 80 kV (P < 0.01) and 140 kV (P < 0.01), and with Rho (P < 0.01). OA was characterized by lower attenuation at 140 kV (P = 0.03), but the lower Rho was nonsignificant after adjustment for confounders. In gout, hyaline cartilage exhibited lower Rho values (adjusted P = 0.04). Multivariable coefficients of association with Rho were -0.21 [-0.38;-0.04] (P = 0.014) for age, -4.15 [-9.0;0.7] (P = 0.093) for OA and 0.73 [-0.1;1.56] (P = 0.085) for monosodium urate volume.

CONCLUSION

Gout was associated with DECT-detected changes in cartilage composition, similar to those observed in older patients, with some similarities and some differences to those seen in OA. These results suggest the possibility of potential DECT biomarkers of OA.

Updates in Ultrasound in Rheumatology

BACKGROUND

The purpose of the authors' narrative review was to outline the current literature regarding the use of ultrasound in main rheumatic disorders and summarize the updates, specifically about rheumatoid arthritis, psoriatic arthritis, and crystal-induced arthropathies.

METHODS

The authors searched on PubMed for articles discussing the major updates regarding the role of ultrasound in the previously mentioned rheumatic conditions.

RESULTS

The authors have provided the updated definitions, new criteria, and diagnostic scores.

CONCLUSIONS

In rheumatology's dynamic landscape, this review provides valuable insights for researchers and clinicians on ultrasound's role in improving patient care and outcomes in rheumatic diseases.

Mononuclear Phagocytes, Cellular Immunity, and Nobel Prizes: A Historic Perspective

The mononuclear phagocyte system includes monocytes, macrophages, some dendritic cells, and multinuclear giant cells. These cell populations display marked heterogeneity depending on their differentiation from embryonic and bone marrow hematopoietic progenitors, tissue location, and activation. They contribute to tissue homeostasis by interacting with local and systemic immune and non-immune cells through trophic, clearance, and cytocidal functions. During evolution, they contributed to the innate host defense before effector mechanisms of specific adaptive immunity emerged. Mouse macrophages appear at mid-gestation and are distributed throughout the embryo to facilitate organogenesis and clear cells undergoing programmed cell death. Yolk sac, AGM, and fetal liver-derived tissue-resident macrophages persist throughout postnatal and adult life, supplemented by bone marrow-derived blood monocytes, as required after injury and infection. Nobel awards to Elie Metchnikoff and Paul Ehrlich in 1908 drew attention to cellular phagocytic and humoral immunity, respectively. In 2011, prizes were awarded to Jules Hoffmann and Bruce Beutler for contributions to innate immunity and to Ralph Steinman for the discovery of dendritic cells and their role in antigen presentation to T lymphocytes. We trace milestones in the history of mononuclear phagocyte research from the perspective of Nobel awards bearing directly and indirectly on their role in cellular immunity.

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.

Peripheral neuropathy in patients with gout, beyond focal nerve compression: a cross-sectional study

Neuropathies secondary to tophus compression in gout patients are well known; however, limited data exist on other types of peripheral neuropathies (PN). Our aim was to describe PN frequency, characteristics, distribution, patterns, and associated factors in gout patients through clinical evaluation, a PN questionnaire, and nerve conduction studies (NCS). This cross-sectional descriptive study included consecutive gout patients (ACR/EULAR 2015 criteria) from our clinic. All underwent evaluation by Rheumatology and Rehabilitation departments, with IRB approval. Based on NCS, patients were categorized as PN + (presence) or PN- (absence). PN + patients were further classified as local peripheral neuropathy (LPN) or generalized somatic peripheral neuropathy (GPN). We enrolled 162 patients, 98% male (72% tophaceous gout). Mean age (SD): 49.4 (12) years; mean BMI: 27.9 (6.0) kg/m2. Comorbidities included dyslipidemia (53%), hypertension (28%), and obesity (23.5%). Abnormal NCS: 65% (n = 106); 52% LPN, 48% GPN. PN + patients were older, had lower education, and severe tophaceous gout. GPN patients were older, had lower education, and higher DN4 scores compared to LPN or PN- groups (p = 0.05); other risk factors were not significant. Over half of gout patients experienced neuropathy, with 48% having multiplex mononeuropathy or polyneuropathy. This was associated with joint damage and functional impairment. Mechanisms and risk factors remain unclear. Early recognition and management are crucial for optimizing clinical outcomes and quality of life in these patients. Key Points Peripheral neuropathies in gout patients had been scarcely reported and studied. This paper report that: • PN in gout is more frequent and more diverse than previously reported. • Mononeuropathies are frequent, median but also ulnar, peroneal and tibial nerves could be injured. • Unexpected, generalized neuropathies (polyneuropathy and multiplex mononeuropathy) are frequent and associated to severe gout. • The direct role of hyperuricemia /or gout in peripheral nerves require further studies.

Correlations of characteristics with tissue involvement in knee gouty arthritis: Magnetic resonance imaging analysis

Objective

This study investigates the MRI features of knee gouty arthritis (KGA), examines its relationship with the extent of tissue involvement, and assesses whether risk factors can predict KGA.

Materials and methods

Patients diagnosed with KGA underwent MRI examinations, and two independent observers retrospectively analyzed data from 44 patients (49 knees). These patients were divided into mild and severe groups based on tissue involvement observed during arthroscopy. MRI features were summarized, and the intraclass correlation coefficient evaluated interobserver reproducibility. Single-factor analysis compared clinical indicators and MRI features between groups, while Cramer's V coefficient assessed correlations. Multivariate logistic regression identified predictors of tissue involvement extent, and a ROC curve evaluated diagnostic performance.

Results

Among 49 knees, 18 had mild and 31 had severe tissue involvement. Key MRI features included ligament sketch-like changes, meniscal urate deposition, irregularly serrated cartilage changes, low-signal signs within joint effusion, synovial proliferation, Hoffa's fat pad synovitis, gouty tophi, bone erosion, and bone marrow edema. The interobserver reliability of the MRI features was good. Significant differences (P < 0.05) were observed between the groups for anterior cruciate ligament (ACL) sketch-like changes, Hoffa's fat pad synovitis, and gouty tophi. ACL sketch-like changes (r = 0.309), Hoffa's fat pad synovitis (r = 0.309), and gouty tophi (r = 0.408) were positively correlated with the extent of tissue involvement (P < 0.05). ACL sketch-like changes (OR = 9.019, 95 % CI: 1.364-61.880), Hoffa's fat pad synovitis (OR = 6.472, 95 % CI: 1.041-40.229), and gouty tophi (OR = 5.972, 95 % CI: 1.218-29.276) were identified as independent predictors of tissue involvement extent (P < 0.05). The area under the ROC curve was 0.862, with a sensitivity of 67.70 %, specificity of 94.40 %, and accuracy of 79.14 %.

Conclusion

This comprehensive analysis of MRI features identifies ligament sketch-like changes, meniscal urate deposition, and low-signal signs within joint effusion as characteristic MRI manifestations of KGA. Irregular cartilage changes are valuable for differential diagnosis in young and middle-aged patients. ACL sketch-like changes, Hoffa's fat pad synovitis, and gouty tophi correlate with tissue involvement severity and are critical in predicting and assessing the extent of tissue involvement in KGA.

Clinical implications of persistent joint pain after gout flare

OBJECTIVES

A subset of gout patients developed persistent joint pain after flares. Analysis of this clinical phenomenon may shed further light on the factors related to worsening gout and even provide clues to its pathogenesis.

METHODS

We analyzed the clinical, laboratory, and ultrasound data of gout patients to explore the associations of these data with persistent joint pain after gout flares.

RESULTS

A total of 1029 gout patients were included: 182 (17.7%) patients with persistent joint pain and 847 (82.3%) patients with nonpersistent joint pain. Patients with persistent joint pain had more total involved joints, more gout flares in the past year, and more joints with simultaneous gout flares (P<0.01). Among the ultrasound-detected lesions, patients with persistent joint pain had a higher incidence of tophus (36.4% vs. 21.1%) and bone erosion (18.6% vs. 8.6%) (P<0.05). Higher UA and lower TBil were found in patients with persistent joint pain (P<0.001). Hypertension (54.9% vs. 38.7%) and metabolic syndrome (58.8% vs. 46.4%) were both more frequent in patients with persistent joint pain (P<0.05). TBil was negatively correlated with the incidence of persistent joint pain (P<0.001, r=-0.190), UA values (P<0.001, r=-0.125), and metabolic syndrome scores (P<0.001, r=-0.192). A correlation curve was fitted using LOESS (locally weighted region).

CONCLUSION

Persistent joint pain after gout flares is a marker of increased disease burden in gout. The significance of the level of total bilirubin for the exacerbation of gout deserves further study.

Analysis of the relationship of refractory gout between potential biomarkers and diet structure and lifestyle based on 1H-NMR

OBJECTIVE

We investigated the different life styles among the diet structures and exercise patterns of 100 patients with refractory gout and 79 healthy volunteers; of these, we selected 39 patients and 20 healthy volunteers for serum proton magnetic resonance (1H-NMR) metabolic network detection. We determined the potential biomarkers of refractory gout and attempted to explore the relation between potential biomarkers and diet structures and exercise patterns.

METHODS

The study employed a questionnaire survey to analyze diet structures and exercise patterns from 100 patients of refractory gout and 79 healthy volunteers. At the same time, using 1H-NMR metabolic technology to analyze the metabolites present in the serum samples obtained from 39 patients of refractory gout (group B) and 20 healthy subjects (group A). Employing MestReNova (Version 8.0.1) to analyze the metabolites maps, collecting the NMR results, further importing into SIMCA-P+ 14.0 software (Umetrics, Sweden) for principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA) statistical analysis. Combining patterns recognition and multivariate statistics, potential biomarkers were searched. Other experimental data, including creatinine and adiponectin, were counted by the SPSS21.0. The measurement data were expressed by X ± S and t test. The counting data were expressed in percent and performed by X2 test.

RESULTS

Our results revealed that patients with gout tended to be obese, and there were differences in their lifestyle with exercise, sleep, and smoking, as well as in their preference for fructose drinks, alcohol, and total and structural distribution of meat, milk, eggs, and so on when compared with the healthy volunteers. Importantly, we found the adiponectin in the gout group was lower as compared to the healthy group. Further, metabolomics in combination with KEGG analysis revealed that the biosynthesis of aminoacyl tRNA, biosynthesis of valine, leucine, and isoleucine, metabolism of alanine, aspartic, and glutamate, metabolism of glycine, serine, and threonine, phenylalanine, glycolysis/gluconeogenesis, ketone body synthesis and degradation, metabolism of D-glutamine, citric acid cycle (TCA cycle), triglyceride metabolism, and others could be used as specific biomarkers of this disease.

CONCLUSION

Recurrent refractory gout and formation of tophus may be related to the diet structures and lifestyles between the patients and the healthy people, and their abnormal metabolic network may be related to the disorder of mitochondrial energy metabolism, which further results in abnormal metabolism of glucose, lipids, amino acids, and deposition of uric acid in joints, peripheral connective tissue, and kidney, inducing an inflammatory response.

Randomized, Double-Blind, Placebo-Controlled, Phase I, Dose- Escalation Study to Evaluate the Tolerance, Pharmacokinetics, Pharmacodynamics and Immunogenicity of PEGylated Urate Oxidase for Injection in Healthy Adults and Hyperuricemia Volunteers: Study Protocol

Introduction

Hyperuricemia is a disease with abnormal purine metabolism, which leads to the increase of urate concentration. It is an independent risk factor for the occurrence and development of metabolic syndrome, type 2 diabetes, hypertension, cardiovascular disease, chronic kidney disease, and gout. The enzyme urate oxidase can metabolize urate to allantoin, resulting in decreased urate concentrations. Pegylated the urate oxidase can extend half-life and decrease immunogenicity of the protein. This trial aims to evaluate the safety, tolerability, pharmacokinetics(PK), pharmacodynamics(PD) and immunogenicity of a new intravenous PEGylated urate oxidase produced by Xiuzheng Bio-Medicine Research Institute Co., Ltd.

Methods and Analysis

A randomized, double-blind, placebo-controlled, phase I, dose escalation study will be conducted in China. In total, 56 subjects will be enrolled in the study, with 24 healthy subjects in the low dose-escalation stage and 32 patients with hyperuricemia in the high dose-escalation stage. There is a bridging between the two stages. Subjects are randomized to PEGylated urate oxidase or the placebo in a 3:1 ratio in each group and followed up for 71 days observation. The primary outcomes include PK, PD, tolerability; the secondary outcomes include safety and immunogenicity.

Ethics and Dissemination

The trial is performed abiding by the Declaration of Helsinki, Good clinical practice (GCP) and the guidelines of China National Medical Products Administration (NMPA). Relevant documents, including protocol, informed consent and drug inspection report, are all approved independently by the Medical Ethics Committee of the Affiliated Hospital of Qingdao University. The first subject was enrolled on January 17, 2022.

Trial Registration

Clinicaltrials, NCT05226013 (Registered April 2, 2022, Retrospectively registered). ChinaDrugTrials, CTR20211801(Registered July 27, 2021).

Emerging Urate-Lowering Drugs and Pharmacologic Treatment Strategies for Gout: A Narrative Review

Hyperuricemia with consequent monosodium urate crystal deposition leads to gout, characterized by painful, incapacitating inflammatory arthritis flares that are also associated with increased cardiovascular event and related mortality risk. This narrative review focuses on emerging pharmacologic urate-lowering treatment (ULT) and management strategies in gout. Undertreated, gout can progress to palpable tophi and joint damage. In oral ULT clinical trials, target serum urate of < 6.0 mg/dL can be achieved in ~ 80-90% of subjects, with flare burden reduction by 1-2 years. However, real-world ULT results are far less successful, due to both singular patient nonadherence and prescriber undertreatment, particularly in primary care, where most patients are managed. Multiple dose titrations commonly needed to optimize first-line allopurinol ULT monotherapy, and substantial potential toxicities and other limitations of approved, marketed oral monotherapy ULT drugs, promote hyperuricemia undertreatment. Common gout comorbidities with associated increased mortality (e.g., moderate-severe chronic kidney disease [CKD], type 2 diabetes, hypertension, atherosclerosis, heart failure) heighten ULT treatment complexity and emphasize unmet needs for better and more rapid clinically significant outcomes, including attenuated gout flare burden. The gout drug armamentarium will be expanded by integrating sodium-glucose cotransporter-2 (SGLT2) inhibitors with uricosuric and anti-inflammatory properties as well as clinically indicated antidiabetic, nephroprotective, and/or cardioprotective effects. The broad ULT developmental pipeline is loaded with multiple uricosurics that selectively target uric acid transporter 1 (URAT1). Evolving ULT approaches include administering selected gut anaerobic purine degrading bacteria (PDB), modulating intestinal urate transport, and employing liver-targeted xanthine oxidoreductase mRNA knockdown. Last, emerging measures to decrease the immunogenicity of systemically administered recombinant uricases should simplify treatment regimens and further improve outcomes in managing the most severe gout phenotypes.

Metabolomic analysis for asymptomatic hyperuricemia and gout based on a combination of dried blood spot sampling and mass spectrometry technology

BACKGROUND

Gout is the most common inflammatory arthritis and closely related to metabolic syndrome, leading to excruciating pain and the decline in quality of patients' life. However, the pathogenesis of gout is still unclear, and novel biomarkers are demanded for the early prediction and diagnosis of gout.

OBJECTIVE

This study aimed at profiling the dysregulated metabolic pathways in asymptomatic hyperuricemia (AHU) and gout and elucidating the associations between AHU, gout and metabolomics, which may aid in performing gout screening.

METHODS

A total of 300 participants, including 114 healthy controls, 92 patients with AHU, and 94 patients with gout, were analyzed by using a combination of dried blood spot (DBS) sampling and mass spectrometry (MS) technology. Multiple algorithms were applied to characterize altered metabolic profiles in AHU and gout. The mainly altered metabolites were identified by random forest analysis.

RESULTS

There were significant differences in AHU and gout compared with control group. The altered metabolites were involved in oxidation of fatty acids, carnitine synthesis, urea cycle, and amino acid metabolism in AHU and gout. Random forest classification of 16 metabolites yielded 3 important features to distinguish gout from AHU.

CONCLUSIONS

Distinct metabolomic signatures were observed in AHU and gout. The selected metabolites may have the potential to improve the early detection of gout.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Amplification of Inflammation by Lubricin Deficiency Implicated in Incident, Erosive Gout Independent of Hyperuricemia

OBJECTIVE

In gout, hyperuricemia promotes urate crystal deposition, which stimulates the NLRP3 inflammasome and interleukin-1β (IL-1β)-mediated arthritis. Incident gout without background hyperuricemia is rarely reported. To identify hyperuricemia-independent mechanisms driving gout incidence and progression, we characterized erosive urate crystalline inflammatory arthritis in a young female patient with normouricemia diagnosed as having sufficient and weighted classification criteria for gout according to the American College of Rheumatology (ACR)/EULAR gout classification criteria (the proband).

METHODS

We conducted whole-genome sequencing, quantitative proteomics, whole-blood RNA-sequencing analysis using serum samples from the proband. We used a mouse model of IL-1β-induced knee synovitis to characterize proband candidate genes, biomarkers, and pathogenic mechanisms of gout.

RESULTS

Lubricin level was attenuated in human proband serum and associated with elevated acute-phase reactants and inflammatory whole-blood transcripts and transcriptional pathways. The proband had predicted damaging gene variants of NLRP3 and of inter-α trypsin inhibitor heavy chain 3, an inhibitor of lubricin-degrading cathepsin G. Changes in the proband's serum protein interactome network supported enhanced lubricin degradation, with cathepsin G activity increased relative to its inhibitors, SERPINB6 and thrombospondin 1. Activation of Toll-like receptor 2 (TLR-2) suppressed levels of lubricin mRNA and lubricin release in cultured human synovial fibroblasts (P < 0.01). Lubricin blunted urate crystal precipitation and IL-1β induction of xanthine oxidase and urate in cultured macrophages (P < 0.001). In lubricin-deficient mice, injection of IL-1β in knees increased xanthine oxidase-positive synovial resident M1 macrophages (P < 0.05).

CONCLUSION

Our findings linked normouricemic erosive gout to attenuated lubricin, with impaired control of cathepsin G activity, compounded by deleterious NLRP3 variants. Lubricin suppressed monosodium urate crystallization and blunted IL-1β-induced increases in xanthine oxidase and urate in macrophages. The collective activities of articular lubricin that could limit incident and erosive gouty arthritis independently of hyperuricemia are subject to disruption by inflammation, activated cathepsin G, and synovial fibroblast TLR-2 signaling.

Three Cases of Gouty Tophus in the Foot Treated by Resection

We encountered three cases of gouty tophus in the foot that required resection. All patients were male and aged 44-68 years at the time of surgery. The lesions were located on the great toe, second toe, and lateral malleolus and were causing ulceration and destruction of the joints. One patient had normal uric acid levels, and another patient had hyperuricemia but no history of attacks and no significant inflammatory symptoms around the gouty tophus, which was attributed to the physical containment of uric acid crystals by the gouty tophus. Given that the crystals were adherent to the surrounding fibrous tissue and cartilage surface, we resected them as far as possible to reduce the total amount of crystals and treated the remaining crystals with uric acid-lowering therapy. There were no complications at the time of surgery. The swelling and bone destruction subsided with continued medical treatment, resulting in significant improvement in quality of life. Patients with gouty tophus should be treated aggressively with medication and monitored to prevent severe joint destruction and ulceration. Excision of the nodule should be considered in cases of exacerbation.

Genetic and Epigenetic Regulation of the Innate Immune Response to Gout

Gout is a disease caused by uric acid (UA) accumulation in the joints, causing inflammation. Two UA forms - monosodium urate (MSU) and soluble uric acid (sUA) have been shown to interact physically with inflammasomes, especially with the nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3), albeit the role of the immune response to UA is poorly understood, given that asymptomatic hyperuricemia does also exist. Macrophage phagocytosis of UA activate NLRP3, lead to cytokines release, and ultimately, lead to chemoattract neutrophils and lymphocytes to the gout flare joint spot. Genetic variants of inflammasome genes and of genes encoding their molecular partners may influence hyperuricemia and gout susceptibility, while also influencing other comorbidities such as metabolic syndrome and cardiovascular diseases. In this review, we summarize the inflammatory responses in acute and chronic gout, specifically focusing on innate immune cell mechanisms and genetic and epigenetic characteristics of participating molecules. Unprecedently, a novel UA binding protein - the neuronal apoptosis inhibitor protein (NAIP) - is suggested as responsible for the asymptomatic hyperuricemia paradox.Abbreviation: β2-integrins: leukocyte-specific adhesion molecules; ABCG2: ATP-binding cassete family/breast cancer-resistant protein; ACR: American college of rheumatology; AIM2: absent in melanoma 2, type of pattern recognition receptor; ALPK1: alpha-protein kinase 1; ANGPTL2: angiopoietin-like protein 2; ASC: apoptosis-associated speck-like protein; BIR: baculovirus inhibitor of apoptosis protein repeat; BIRC1: baculovirus IAP repeat-containing protein 1; BIRC2: baculoviral IAP repeat-containing protein 2; C5a: complement anaphylatoxin; cAMP: cyclic adenosine monophosphate; CARD: caspase activation and recruitment domains; CARD8: caspase recruitment domain-containing protein 8; CASP1: caspase 1; CCL3: chemokine (C-C motif) ligand 3; CD14: cluster of differentiation 14; CD44: cluster of differentiation 44; Cg05102552: DNA-methylation site, usually cytosine followed by guanine nucleotides; contains arbitrary identification code; CIDEC: cell death-inducing DNA fragmentation factor-like effector family; CKD: chronic kidney disease; CNV: copy number variation; CPT1A: carnitine palmitoyl transferase - type 1a; CXCL1: chemokine (CXC motif) ligand 1; DAMPs: damage associated molecular patterns; DC: dendritic cells; DNMT(1): maintenance DNA methyltransferase; eQTL: expression quantitative trait loci; ERK1: extracellular signal-regulated kinase 1; ERK2: extracellular signal-regulated kinase 2; EULAR: European league against rheumatism; GMCSF: granulocyte-macrophage colony-stimulating factor; GWAS: global wide association studies; H3K27me3: tri-methylation at the 27th lysine residue of the histone h3 protein; H3K4me1: mono-methylation at the 4th lysine residue of the histone h3 protein; H3K4me3: tri-methylation at the 4th lysine residue of the histone h3 protein; HOTAIR: human gene located between hoxc11 and hoxc12 on chromosome 12; IκBα: cytoplasmatic protein/Nf-κb transcription inhibitor; IAP: inhibitory apoptosis protein; IFNγ: interferon gamma; IL-1β: interleukin 1 beta; IL-12: interleukin 12; IL-17: interleukin 17; IL18: interleukin 18; IL1R1: interleukin-1 receptor; IL-1Ra: interleukin-1 receptor antagonist; IL-22: interleukin 22; IL-23: interleukin 23; IL23R: interleukin 23 receptor; IL-33: interleukin 33; IL-6: interleukin 6; IMP: inosine monophosphate; INSIG1: insulin-induced gene 1; JNK1: c-jun n-terminal kinase 1; lncRNA: long non-coding ribonucleic acid; LRR: leucine-rich repeats; miR: mature non-coding microRNAs measuring from 20 to 24 nucleotides, animal origin; miR-1: miR followed by arbitrary identification code; miR-145: miR followed by arbitrary identification code; miR-146a: miR followed by arbitrary identification code, "a" stands for mir family; "a" family presents similar mir sequence to "b" family, but different precursors; miR-20b: miR followed by arbitrary identification code; "b" stands for mir family; "b" family presents similar mir sequence to "a" family, but different precursors; miR-221: miR - followed by arbitrary identification code; miR-221-5p: miR followed by arbitrary identification code; "5p" indicates different mature miRNAs generated from the 5' arm of the pre-miRNA hairpin; miR-223: miR followed by arbitrary identification code; miR-223-3p: mir followed by arbitrary identification code; "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; miR-22-3p: miR followed by arbitrary identification code, "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; MLKL: mixed lineage kinase domain-like pseudo kinase; MM2P: inductor of m2-macrophage polarization; MSU: monosodium urate; mTOR: mammalian target of rapamycin; MyD88: myeloid differentiation primary response 88; n-3-PUFAs: n-3-polyunsaturated fatty-acids; NACHT: acronym for NAIP (neuronal apoptosis inhibitor protein), C2TA (MHC class 2 transcription activator), HET-E (incompatibility locus protein from podospora anserina) and TP1 (telomerase-associated protein); NAIP: neuronal apoptosis inhibitory protein (human); Naip1: neuronal apoptosis inhibitory protein type 1 (murine); Naip5: neuronal apoptosis inhibitory protein type 5 (murine); Naip6: neuronal apoptosis inhibitory protein type 6 (murine); NBD: nucleotide-binding domain; Nek7: smallest NIMA-related kinase; NET: neutrophil extracellular traps; Nf-κB: nuclear factor kappa-light-chain-enhancer of activated b cells; NFIL3: nuclear-factor, interleukin 3 regulated protein; NIIMA: network of immunity in infection, malignancy, and autoimmunity; NLR: nod-like receptor; NLRA: nod-like receptor NLRA containing acidic domain; NLRB: nod-like receptor NLRA containing BIR domain; NLRC: nod-like receptor NLRA containing CARD domain; NLRC4: nod-like receptor family CARD domain containing 4; NLRP: nod-like receptor NLRA containing PYD domain; NLRP1: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 1; NLRP12: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 12; NLRP3: nod-like receptor family pyrin domain containing 3; NOD2: nucleotide-binding oligomerization domain; NRBP1: nuclear receptor-binding protein; Nrf2: nuclear factor erythroid 2-related factor 2; OR: odds ratio; P2X: group of membrane ion channels activated by the binding of extracellular; P2X7: p2x purinoceptor 7 gene; p38: member of the mitogen-activated protein kinase family; PAMPs: pathogen associated molecular patters; PBMC: peripheral blood mononuclear cells; PGGT1B: geranylgeranyl transferase type-1 subunit beta; PHGDH: phosphoglycerate dehydrogenase; PI3-K: phospho-inositol; PPARγ: peroxisome proliferator-activated receptor gamma; PPARGC1B: peroxisome proliferative activated receptor, gamma, coactivator 1 beta; PR3: proteinase 3 antigen; Pro-CASP1: inactive precursor of caspase 1; Pro-IL1β: inactive precursor of interleukin 1 beta; PRR: pattern recognition receptors; PYD: pyrin domain; RAPTOR: regulatory associated protein of mTOR complex 1; RAS: renin-angiotensin system; REDD1: regulated in DNA damage and development 1; ROS: reactive oxygen species; rs000*G: single nuclear polymorphism, "*G" is related to snp where replaced nucleotide is guanine, usually preceded by an id number; SLC2A9: solute carrier family 2, member 9; SLC7A11: solute carrier family 7, member 11; SMA: smooth muscular atrophy; Smac: second mitochondrial-derived activator of caspases; SNP: single nuclear polymorphism; Sp3: specificity protein 3; ST2: serum stimulation-2; STK11: serine/threonine kinase 11; sUA: soluble uric acid; Syk: spleen tyrosine kinase; TAK1: transforming growth factor beta activated kinase; Th1: type 1 helper T cells; Th17: type 17 helper T cells; Th2: type 2 helper T cells; Th22: type 22 helper T cells; TLR: tool-like receptor; TLR2: toll-like receptor 2; TLR4: toll-like receptor 4; TNFα: tumor necrosis factor alpha; TNFR1: tumor necrosis factor receptor 1; TNFR2: tumor necrosis factor receptor 2; UA: uric acid; UBAP1: ubiquitin associated protein; ULT: urate-lowering therapy; URAT1: urate transporter 1; VDAC1: voltage-dependent anion-selective channel 1.

Dynamic assessment of the double contour sign by ultrasonography helps to distinguish between gout and calcium pyrophosphate deposition disease

OBJECTIVE

To test whether the double contour (DC) sign has a different dynamic behaviour in gout and calcium pyrophosphate deposition (CPPD) and whether the dynamic assessment of the DC sign increases its accuracy in gout diagnosis.

METHODS

This cross-sectional analysis included patients with gout meeting the 2015 ACR/EULAR classification criteria and patients with crystal-proven diagnosis of CPPD. Hyaline cartilages were explored by ultrasound (US) to detect the DC sign (ie, abnormal hyperechoic band over the superficial margin of hyaline cartilages) and its dynamic behaviour during joint movement was evaluated ((ie, movement of the DC sign together with subchondral bone (DC sign), or in the opposite direction (pseudo DC sign)).

RESULTS

Eighty-one patients with gout and 84 patients with CPPD underwent US assessment. Among them, 47 patients with gout and 9 patients with CPPD had evidence of the DC sign. During dynamic assessment, in all 47/47 patients with gout there was a DC sign. Conversely, in 7/9 (77.8%) patients with CPPD, there was a pseudo DC sign (p<0.01).The presence of DC sign during static assessment had a sensitivity, specificity and accuracy of 58.0% (95% CI 46.5% to 68.9%), 89.3% (95% CI 80.6% to 95.0%) and 73.9% (95% CI 66.5% to 80.5%) for gout, respectively. The dynamic evaluation improved the DC sign's diagnostic performance (p=0.01) as the specificity (97.6% (95% CI 91.7% to 99.7%)) and the accuracy (78.2% (95% CI 71.1% to 84.2%)) increased without loss in sensitivity.

CONCLUSION

The dynamic US assessment of the DC sign may help to differentiate the DC sign due to MSU crystals from the pseudo DC sign seen in CPPD, as they move in opposite directions.

The application of a novel hydrodynamic cavitation device to debride intra-articular monosodium urate crystals

INTRODUCTION

Efficient and complete debridement of intra-articular deposits of monosodium urate crystals is rarely achieved by existing arthroscopic tools such as shavers or radiofrequency ablation, while cavitation technology represents a prospective solution for the non-invasive clearance of adhesions at intra-articular interfaces.

METHODS

Simulation modeling was conducted to identify the optimal parameters for the device, including nozzle diameters and jet pressures. Gouty arthritis model was established in twelve rats that were equally and randomly allocated into a cavitation debridement group or a curette debridement group. A direct injection nozzle was designed and then applied on animal model to verify the effect of the cavitation jet device on the removal of crystal deposits. Image analysis was performed to evaluate the clearance efficiency of the cavitation device and the pathological features of surrounding tissue were collected in all groups.

RESULTS

To maximize cavitation with the practical requirements of the operation, an experimental rig was applied, including a 1 mm direct injection nozzle with a jet pressure of 2.0 MPa at a distance of 20 mm and a nitrogen bottle as high-pressure gas source. With regards to feasibility of the device, the clearance rates in the cavitation group were over 97% and were significantly different from the control group. Pathological examination showed that the deposition of monosodium urate crystals was removed completely while preserving the normal structure of the collagen fibers.

CONCLUSIONS

We developed a promising surgical device to efficiently remove intra-articular deposits of monosodium urate crystals. The feasibility and safety profile of the device were also verified in a rat model. Our findings provide a non-invasive method for the intraoperative treatment of refractory gouty arthritis.

Effect of Bining decoction on gouty nephropathy: a network pharmacology analysis and preliminary validation of gut microbiota in a mouse model

Background

To use network pharmacology and gut microbiota sequencing to investigate the probable mechanism of Bining decoction (BN) in the treatment of gouty nephropathy (GN).

Methods

Firstly, the mechanism of therapeutic effects of BN on GN were collected by integrating network pharmacology. Secondly, the treatment effects of BN against GN in 30 Institute of Cancer Research (ICR) mice were evaluated by performing biochemical tests [uric acid, blood urea nitrogen, and creatinine (UA, BUN, and Cr)] and evaluating the renal weight index. Finally, 16S rRNA sequencing was utilized for elucidating the therapeutical effect of BN in GN.

Results

The results of gut microbiota sequencing analysis showed the abundance of Faecalibaculum, Romboutsia, Bifidobacterium, Bacteroides, Odoribacter, Lachnospiraceae NK4A136 group, unclassified_f__Lachnospiraceae, Roseburia, norank_f__Lachnospiraceae, Lactobacillus, Dubosiella, norank_f__Muribaculaceae, and Turicibacter in the BN group had a significant changed between-group comparisons. Using a network pharmacology-related database, 413 active components of BN were identified, as well as 1,085 GN-associated targets. The 118 targets of disease targets and component targets were mapped, of which the top 10 genes were selected. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that 157 pathways were enriched, which was partially consistent with the metabolic pathways of gut microbiota sequencing analysis.

Conclusions

Combining 16S rRNA gene sequencing and network pharmacology analysis, similar signaling pathways were followed: "Pathways in cancer" and "Adipocytokine signaling pathway". The results reveal that BN increases the abundance of Turicibacter, regulates the expression of JAK2 in the JAK/STAT pathway, increases the beneficial bacteria Turicibacter associated with intestinal butyric acid, which could enhance the intestinal barrier, and exert anti-inflammatory effects.

Extraction optimization, structural characterization and potential alleviation of hyperuricemia by flavone glycosides from celery seeds

Celery seeds are commonly used as condiments and in herbal teas with high medicinal value. In the present study, we investigated the contents of extracts derived under different extraction conditions and determined the optimal conditions for only extracting flavone glycosides from celery seeds. The compositional analysis identified three primary flavone glycosides in the ethanolic extract, and apiin, graveobioside A, and graveobioside B were isolated. Apigenin, luteolin, and chrsyeriol were obtained by the acid hydrolysis of flavone glycosides under high-temperature conditions. Here we investigated the inhibitory activity of apigenin and apiin on xanthine oxidase by reducing the rate of oxidative cytochrome C and found that both apigenin and apiin reduced cytochrome C production, except for low concentrations of apiin. In vivo analysis with hyperuricemia mice and rats showed that apiin had excellent uric acid-lowering effects and high dose-dependence, while apigenin was relatively slightly uric acid-lowering. In addition, the flavone glycoside extracts from celery seeds exhibited similar effects of reducing uric acid with apiin. Surprisingly, in hyperuricemia rats, the uric acid-lowering effects of high-dose apiin and flavone glycoside extracts were almost comparable to that of allopurinol. Besides, our experimental results showed that apigenin could improve uric acid clearance by increasing the glomerular filtration capacity, which was reflected in reducing the renal function parameters SUN and SCr; also, apiin showed better results. This study also showed that celery seeds have a unique medicinal value in treating hyperuricemia and that the flavone glycoside extracts from celery seeds can be developed as medicine for hyperuricemia.

Comparison of MR Findings between Patients with Septic Arthritis and Acute Gouty Arthritis of the Knee

Purpose

To compare the MR findings of septic and acute gouty arthritis of the knee joint.

Materials and Methods

This retrospective study included patients who underwent knee MRI for septic or gouty arthritis at our hospital between October 2012 and October 2018. The MR findings were analyzed for the presence of bone marrow edema, soft tissue edema, abscess, pattern of synovial thickening (frondlike, lamellated, diffuse linear), maximum thickness of the synovium, and joint effusion volume. The gouty (n = 5) and septic arthritis (n = 10) groups were compared using the Wilcoxon rank-sum test and Fisher's exact test.

Results

No statistically significant differences were observed for each item. One patient in the gouty arthritis group and seven in the septic arthritis group had bone marrow edema. Soft tissue abscess formation was only observed in the septic group. The incidence of each synovial thickening pattern was as follows: 100% (diffuse linear) in the gouty arthritis group and 20% (frondlike), 50% (lamellated), and 30% (diffuse linear) in the septic arthritis group.

Conclusion

Differentiation of gouty arthritis and septic arthritis based on imaging findings is difficult. However, lamellated synovial thickening patterns, bone marrow edema, and soft tissue abscess formation are more commonly observed in patients with septic arthritis than in those with gouty arthritis.

Oral Huzhang granules for the treatment of acute gouty arthritis: protocol for a double-blind, randomized, controlled trial

Background

Acute gouty arthritis (GA) is the main clinical manifestation and the most common initial symptom of gout. The treatment of acute GA involves the use of colchicine, non-steroidal anti-inflammatory drugs, and corticosteroids. Because of the side effects of these drugs, their clinical applications are limited. The use of traditional Chinese medicine for the treatment of acute GA has unique advantages. The aim of this trial is to clarify the treatment efficacy, safety, and recurrence control efficacy of Huzhang granules (HZG) in patients with GA showing dampness-heat syndrome.

Methods/design

This double-blind, randomized, controlled trial was planned to be conducted between July 1, 2020, and December 31, 2022. A sample size of 267 participants (89 per group) with GA will be randomly assigned to three treatment groups in the ratio of 1:1:1: HZG, etoricoxib, and placebo groups. The study duration is 13 days, including a 1-day screening period, 5-day intervention period, and 1-week follow-up period. The primary outcome is analgesic effectiveness, assessed as pain in the worst-affected joint, which will be measured using the visual analog scale. Secondary outcomes include the patient’s assessment of pain in the primary study joint, patient’s global assessment of response to therapy, investigator’s global assessment of response to therapy, investigator’s assessment of tenderness and swelling of the study joint, and TCM syndromes. Furthermore, the number, nature, and severity of adverse events will be recorded.

Discussion

This study will provide evidence regarding the clinical efficacy and safety of Chinese medicine treatment for acute gouty arthritis. This study will provide noteworthy findings.

Trial registration

ClinicalTrials.gov NCT04462666. Registered on July 05, 2020 (first version).

Usefulness of ultrasound in the diagnosis of crystal deposition diseases

Gout and calcium pyrophosphate crystal deposition disease (CPPD) are common forms of inflammatory arthritis whose prevalence has increased in recent years. Although the identification of monosodium urate crystals (MSU) and calcium pyrophosphate crystals (CPP) in synovial fluid (SF) by polarized light microscopy are the gold standard for diagnosing these diseases, SF analysis is not always available. An early diagnosis and specific treatment, especially in gout, allows avoiding irreversible structural damage, comorbidities, and a severe impact on the quality of life of patients. Musculoskeletal ultrasound (US) is a noninvasive tool that allows detecting aggregates of microcrystals at multiple anatomical sites and helps to establish a specific diagnosis. The objective of this review is to evaluate the applications of US in the diagnosis and clinical management of the main microcrystalline arthropathies. The US has helped improve our understanding of the natural history of the disease, due to its ability to visualize not only soft tissue inflammation and structural damage, but also the characteristics of MSU and CPP crystal deposition. The anatomical sites of crystal deposition are also a key factor for differential diagnosis in different microcrystalline diseases. The US allows establishing an early diagnosis, especially in asymptomatic hyperuricemia, to discriminate with other inflammatory diseases, to assess the extent of microcrystalline deposition and their sensitivity to change after treatment. Given its increasing availability in clinical practice and strong evidence, US is a bedside imaging technique helping clinicians to improve diagnosis and therapy monitoring in their daily practice.

Clinical Overview of Arthritis with a Focus on Management Options and Preventive Lifestyle Measures for Its Control

ABSTRACT:

Arthritis is the spectrum of conditions that cause swelling and tenderness of one or more body joints with key symptoms of joint pain and stiffness. Its progression is closely tied to age. Although there are a number of arthritis types, such as, ankylosing, gout, joint infections, juvenile idiopathic, reactive and septic; the two most common types are osteoarthritis and rheumatoid arthritis. Osteoarthritis causes the articulating smooth cartilage that covers the ends of bones, where they form a joint, to breakdown. Rheumatoid arthritis is a disease in which the immune system attacks joints, beginning with the cartilaginous lining of the joints. The latter is considered a systemic disease, i.e. affecting many parts of the body, but the respiratory system is involved in 10 to 20 % of all mortality. Osteoarthritis is one of the leading causes of disability globally. Several preventive measures to control arthritis have been suggested, such as the use of analgesics, non-steroid anti-inflammatory drugs, moderate to vigorous physical activity and exercise, reducing sedentary hours, getting adequate sleep and maintaining a healthy body weight. Foods including, a Mediterranean diet rich in fruits and vegetables, fish oil, medicinal plants and microbiota are vital protective methods. The intake of vitamins such as A and C, minerals e.g., selenium and zinc; poly unsaturated and n-3 fatty acids is also a significant preventive measures.

Surgically treated reactive arthritis of the ankle after COVID-19 infection: A case report

A 37-year-old man developed right ankle pain and swelling six days after being diagnosed with coronavirus disease (COVID-19). Despite conservative treatment, his ankle symptoms persisted. Magnetic resonance imaging and computed tomography showed synovial hypertrophy and bone erosion in the ankle. Following arthroscopic synovectomy, performed 69 days after the COVID-19 diagnosis, the pain improved significantly. The clinical course was consistent with that of reactive arthritis following severe acute respiratory syndrome coronavirus 2 infection. The pathological findings resembled rheumatoid nodules. The bone erosion may have originated from the inflammatory pathway, which resembles the mechanism of rheumatoid arthritis.

Gouty Arthropathy: Review of Clinical Manifestations and Treatment, with Emphasis on Imaging

Gout, a crystalline arthropathy caused by the deposition of monosodium urate crystals in the articular and periarticular soft tissues, is a frequent cause of painful arthropathy. Imaging has an important role in the initial evaluation as well as the treatment and follow up of gouty arthropathy. The imaging findings of gouty arthropathy on radiography, ultrasonography, computed tomography, dual energy computed tomography, and magnetic resonance imaging are described to include findings of the early, acute and chronic phases of gout. These findings include early monosodium urate deposits, osseous erosions, and tophi, which may involve periarticular tissues, tendons, and bursae. Treatment of gout includes non-steroidal anti-inflammatories, colchicine, glucocorticoids, interleukin-1 inhibitors, xanthine oxidase inhibitors, uricosuric drugs, and recombinant uricase. Imaging is critical in monitoring response to therapy; clinical management can be modulated based on imaging findings. This review article describes the current standard of care in imaging and treatment of gouty arthropathy.

Distribution of bony erosions in feet and performance of two bone erosion scores: A dual-energy computed tomography study of 61 patients with gout

OBJECTIVES

To assess the distribution of bone erosions and two erosion scores in the feet of patients with gout and analyze the association between erosion scores and monosodium urate (MSU) crystal deposition using dual-energy computed tomography (DECT).

MATERIALS AND METHODS

We included all patients who underwent DECT of both feet between 2016 and 2019 in our radiology department, with positive detection of MSU deposits. Data on sex, age, treatment, serum urate, and DECT urate volumes were obtained. CT images were analyzed to score bone erosions in 31 sites per foot by using the semi-quantitative method based on the Rheumatoid Arthritis MRI Scoring (RAMRIS) system and the Dalbeth-simplified score. Reproducibility for the two scores was calculated with intraclass correlation coefficients (ICCs). Correlations between clinical features, erosion scores and urate crystal volume were analyzed by the Spearman correlation coefficient (r).

RESULTS

We studied 61 patients (mean age 62.0 years); 3,751 bones were scored. The first metatarsophalangeal joint and the midfoot were the most involved in terms of frequency and severity of bone erosions. The distribution of bone erosions was not asymmetrical. The intra- and inter-observer reproducibility was similar for the RAMRIS and Dalbeth-simplified scores (ICC 0.93 vs 0.94 and 0.96 vs 0.90). DECT urate volume was significantly correlated with each of the two erosion scores (r = 0.58-0.63, p < 0.001). There was a high correlation between the two scores (r = 0.96, p < 0.001).

CONCLUSIONS

DECT demonstrates that foot erosions are not asymmetric in distribution and predominate at the first ray and midfoot. The two erosion scores are significantly correlated with DECT urate volume. An almost perfect correlation between the RAMRIS and Dalbeth-simplified scores is observed.

Post-ACL Reconstruction Graft Failure in Severe Gout Arthritis Patient

Introduction

Pain and instability following an anterior cruciate ligament (ACL) reconstruction remain a significant issue. Common causes include infection and inflammation, and mechanical issues such as graft failure.

Case Presentation

A 36-year-old male with an ACL reconstruction six years prior was admitted due to pain and swelling. The ACL graft that had ruptured was found arthroscopically. Numerous gout crystals and tophus were observed inside. This finding is suggested as a cause of this kind of complication.

Discussion

Biological failure is one of the causes of graft failure. Gout arthritis is associated with internal derangement of the joint structures, which is reported in advanced case.

Conclusion

Severe gouty arthritis, even though rare, could be an etiology of graft failure following ACL reconstruction and cause significant morbidity.

Gout Storm

Patient: Male, 55-year-old

Final Diagnosis: Gout • spinal gout

Symptoms: Back pain • fever • incontinence • pain • paresthesia of extremities • tachycardia

Medication: —

Clinical Procedure: Antibiotics • arthrocentesis • biopsy • CT scan • surgery • ultrasonography

Specialty: General and Internal Medicine

Hearing loss due to urate deposition in the middle ear: A case report and literature review

Gout is the most common cause of monoarthritis in men occurring classically in the great toe and the knee. Extra-articular gout manifestations are rare. Only a few cases of head and neck urate crystals deposits have been described in the literature. Precipitations in the middle ear cause conductive hearing loss with common otoscopic anomalies and difficult imaging diagnosis.

We report a case of a healthy 58-years-old man with a middle ear urate deposit causing a progressive hearing loss as the very first symptom of gout. The nature of the deposit was unsure on computer tomography (CT) due to atypical density. The final diagnosis was revealed after surgical procedure and histologic examination.

A review of the literature is also presented. Seven cases of middle ear urate deposit as the first symptom of gout were found and compared.

Progressive conductive hearing loss in middle-aged patients with abnormal otoscopy and middle ear atypical density mass on CT scan must lead to a minimal surgical procedure with a histologic examination to exclude urate crystals deposits.

Middle ear urate deposit can be the very first symptom of gout.

Middle ear deposition causes conductive hearing loss with abnormal otoscopy.

Computer tomography shows an abnormal density mass.

Minimal surgical procedure with histologic examination makes the final diagnosis.

Only seven similar cases have been described.

Limitations of dual-energy CT in the detection of monosodium urate deposition in dense liquid tophi and calcified tophi

OBJECTIVE

Dual-energy CT (DECT) detection of monosodium urate (MSU) crystal deposition has demonstrated good sensitivity and specificity in patients with established gout. However, limitations have been reported with early disease and with low urate burden. We aimed to study the performance of DECT in the detection and quantification of MSU deposition in solid and liquid tophi.

MATERIALS AND METHODS

Patient-derived solid and liquid tophi, suspensions of commercial synthetic, and in-house synthetic MSU crystals were prepared at varying concentrations. DECT was performed at 80 kVp and 150 kVp, and post-processed using Syngo Via gout software (Siemens) that color-coded urate and cortical bone as green and purple, respectively. DECT findings were correlated with ultrasound and microscopic findings. The protocol was reviewed by IRB and considered a non-human subject research.

RESULTS

DECT did not detect urate deposition in either patient-derived liquid tophi or in-house synthetic crystals at any concentration. Lowering the post-processing minimum threshold increased the detection of in-house synthetic crystals but did not change the detection of patient-derived liquid tophi. Areas of calcium-rich purple color-coded regions, masking detection of urate, within the solid tophi and surrounding liquid tophi were noted on DECT. Histology showed co-presence of calcium along with MSU deposition in these.

CONCLUSION

This study illustrates important limitations of DECT for liquid tophi due to subthreshold CT attenuation and for calcified tophi due to the obscuration of urate by calcium. Urate may be either undetectable or underestimated by DECT when these conditions are present.

Curcumin modulates gut microbiota and improves renal function in rats with uric acid nephropathy

It is well known that the progression of hyperuricemia disease often contributes to renal dysfunction. However, there have been few studies on uric acid nephropathy (UAN), especially its relationship with gut microbiota. UAN is usually accompanied by disordered intestinal flora, and damaged gut barrier, which are closely related to tubulointerstitial fibrosis, and systemic inflammation. In previous studies, it has been confirmed that curcumin could alleviate tubulointerstitial fibrosis, and improve renal function through its antioxidant, anti-apoptotic, and anti-inflammatory efficacies. However, the effects curcumin exerts on intestinal flora in uric acid nephropathy are still unknown. Therefore, we used next-generation sequencing technology to investigate the effects of curcumin on gut microbiota in a rat model of UAN induced by adenine and potassium oxonate, and rats were randomly divided into control, model or curcumin treatment groups. The results demonstrated that, compared to the model group, the treatment group showed decreased serum uric acid (156.80 ± 11.90 μmol/L vs. 325.60 ± 18.65 μmol/L, p < 0.001), serum creatinine (66.20 ± 11.88 μmol/L vs. 182.20 ± 8.87 μmol/L, p < 0.001) and BUN level (13.33 ± 3.16 mmol/L vs. 36.04 ± 6.60 mmol/L, p < 0.001). The treatment group also displayed attenuated renal pathological lesions and metabolic endotoxemia (25.60 ± 5.90 ng/mL vs. 38.40 ± 4.98 ng/mL, p < 0.01), and improved tightly linked proteins expression. Besides, curcumin altered the gut microbiota structure in UAN rats. More specifically, curcumin treatment protected against the overgrowth of opportunistic pathogens in UAN, including Escherichia-Shigella and Bacteroides, and increased the relative abundance of bacteria producing short‐chain fatty acids (SCFAs), such as Lactobacillus and Ruminococcaceae. These results suggest that curcumin could modulate gut microbiota, fortify the intestinal barrier, attenuate metabolic endotoxemia, and consequently protect the renal function in UAN rats.

Severe erosive lesion of the glenoid in gouty shoulder arthritis: a case report and review of the literature

Background

Gout is a metabolic disease characterized by recurrent episodes of acute arthritis. Gout has been reported in many locations but is rarely localized in the shoulder joint. We describe a rare case of gouty arthritis involving bilateral shoulder joints and leading to severe destructive changes in the right shoulder glenoid.

Case presentation

A 62-year-old male was referred for pain and weakness in the right shoulder joint for two years, and the pain had increased in severity over the course of approximately nine months. A clinical examination revealed gout nodules on both feet and elbows. A laboratory examination showed a high erythrocyte sedimentation rate (ESR), high levels of C-reactive protein and hyperuricemia, and an imaging examination showed severe osteolytic destruction of the right shoulder glenoid and posterior humeral head subluxation. In addition, the left humeral head was involved and had a lytic lesion. Because a definite diagnosis could not be made for this patient, a right shoulder biopsy was performed. The pathological examination of the specimen revealed uric acid crystal deposits and granulomatous inflammation surrounding the deposits. After excluding infectious and neoplastic diseases, the patient was finally diagnosed with gouty shoulder arthritis.

Conclusions

Gout affecting the bilateral shoulder joints is exceedingly uncommon, and to our knowledge, severe erosion of the glenoid has not been previously reported. When severe erosion is present, physicians and orthopedic surgeons should consider gouty shoulder arthritis according to previous medical history and clinical manifestations.

MRI of the Achilles tendon - a comprehensive pictorial review. Part two

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The abnormalities on MRI should be correlated with the clinical findings.

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Higher signal of the Achilles tendon is a common postoperative finding.

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The fluid signal within the Achilles tendon graft indicates a rupture.

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Postoperative complications of Haglund’s syndrome should be assessed on MRI.

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Elongation of the Achilles tendon is seen after surgical or conservative treatment.

The most common disorder affecting the Achilles tendon is midportion tendinopathy. A focal fluid signal indicates microtears, which may progress to partial and complete rupture. Assessment of Achilles tendon healing should be based on tendon morphology and tension rather than structural signal. After nonoperative management or surgical repair of the Achilles tendon, areas of fluid signal is pathologic because it indicates re-rupture. A higher signal in the postoperative Achilles tendon is a common finding and is present for a prolonged period following surgical intervention and needs to be interpreted alongside the clinical appearance.

Why Does Hyperuricemia Not Necessarily Induce Gout?

Hyperuricemia is a risk factor for gout. It has been well observed that a large proportion of individuals with hyperuricemia have never had a gout flare(s), while some patients with gout can have a normuricemia. This raises a puzzle of the real role of serum uric acid (SUA) in the occurrence of gout flares. As the molecule of uric acid has its dual effects in vivo with antioxidant properties as well as being an inflammatory promoter, it has been placed in a delicate position in balancing metabolisms. Gout seems to be a multifactorial metabolic disease and its pathogenesis should not rely solely on hyperuricemia or monosodium urate (MSU) crystals. This critical review aims to unfold the mechanisms of the SUA role participating in gout development. It also discusses some key elements which are prerequisites for the formation of gout in association with the current therapeutic regime. The compilation should be helpful in precisely fighting for a cure of gout clinically and pharmaceutically.

NEUTROPHIL EXTRACELLULAR TRAPS RELEASE IN GOUT AND PSEUDOGOUT DEPENDS ON THE NUMBER OF CRYSTALS REGARDLESS OF LEUKOCYTE COUNT

OBJECTIVES

Microcrystal-induced arthritis is still an unresolved paradigm for medicine. Overt inflammation may be absent even when crystals occur in synovial fluid. Recently, the production of neutrophil extracellular traps (NETs) embedding monosodium urate crystals (MSU) has been proposed as a possible mechanism of the auto-resolution of the inflammatory phase during gout. We aimed to verify and quantify the release of NETs in synovial fluids during gout and pseudogout attacks and to compare any differences with respect to crystals and neutrophils number, and to analyze activation of necroptosis pathway in synovial fluid from crystal-induced arthritis.

METHODS

Synovial fluid samples were obtained by arthrocentesis from 22 patients presenting acute crystal-induced arthritis, gout or pseudogout (n = 11 each group), and from 10 patients with acute non-crystal arthritis as controls. NETosis was quantified in synovial fluid by nucleic acid stain and by quantification of human neutrophil elastase. Activation of p-MLKL was assessed by western blot.

RESULTS

We observed that synovial fluid neutrophils encountering MSU and CPPD crystals during episodes of gout and pseudogout release NETs in relation to the number of crystals in synovial fluid and irrespective of neutrophil density and type of crystal. This release was accompanied by necroptosis through the activation of the MLKL pathway.

CONCLUSIONS

Our findings suggest that a role of NETs in crystal-induced arthritis is to "trap extracellular particles", including microcrystals. Embedding crystals in aggregates of NETs may be the basis of tophi and CPPD deposition and may have implications for disease evolution, rather than for spontaneous resolution of the acute attack.

Cardiovascular risk in inflammatory arthritis: rheumatoid arthritis and gout

The increased risk of cardiovascular morbidity and mortality in rheumatoid arthritis and gout has been increasingly acknowledged in past decades, with accumulating evidence that gout, just as with rheumatoid arthritis, is an independent cardiovascular risk factor. Although both diseases have a completely different pathogenesis, the underlying pathophysiological mechanisms in systemic inflammation overlap to some extent. Following the recognition that systemic inflammation has an important causative role in cardiovascular disease, anti-inflammatory therapy in both conditions and urate-lowering therapies in gout are expected to lower the cardiovascular burden of patients. Unfortunately, much of the existing data showing that urate-lowering therapy has consistent beneficial effects on cardiovascular outcomes in patients with gout are of low quality and contradictory. We will discuss the latest evidence in this respect. Cardiovascular disease risk management for patients with rheumatoid arthritis and gout is essential. Clinical guidelines and implementation of cardiovascular risk management in daily clinical practice, as well as unmet needs and areas for further investigation, will be discussed.

Xanthine Oxidase and Transforming Growth Factor Beta-activated Kinase 1: Potential Targets for Gout Intervention

BACKGROUND

Gout, inflammatory arthritis caused by the deposition of monosodium urate crystals into affected joints and other tissues, has become one of the major health problems of today's world. The main risk factor for gout is hyperuricemia, which may be caused by excessive or insufficient excretion of uric acid. The incidence is usually in the age group of 30- 50 years, commonly in males. In developed countries, the incidence of gout ranges from 1 to 4%. Despite effective treatments, there has been an increase in the number of cases over the past few decades.

OBJECTIVE

In recent years, the development of targeted drugs in gout has made significant achievements. The global impact of gout continues to increase, and as a result, the focus of disease-modifying therapies remains elusive. In addition, the characterization of available instrumental compounds is urgently needed to explore the use of novel selective and key protein-ligand interactions for the effective treatment of gout. Xanthine oxidase (XO) is a key target in gout to consider the use of XO inhibitors in patients with mild to moderate condition, however, the costs are high, and no other direct progress has been made. Despite many XO inhibitors, a selective potent inhibitor for XO is limited. Likewise, in recent years, attention has been focused on different strategies for the discovery and development of new selectivity ligands against transforming growth factor beta- activated kinase 1 (TAK1), a potential therapeutic target for gout. Therefore, the insight on human XO structure and TAK1 provides a clue into protein-ligand interactions and provides the basis for molecular modeling and structure-based drug design.

CONCLUSION

In this review, we briefly introduce the clinical characteristics, the development of crystal, inhibitors, and crystal structure of XO and TAK1 protein.

Volumetric reduction and dissolution prediction of monosodium urate crystal during urate-lowering therapy - a study using dual-energy computed tomography

METHODS

Baseline and follow-up DECTs were performed under a standard ULT protocol. Monthly dissolution rates were calculated by simple and compound methods. Correlations with average SU were compared and analyzed. Best-fit regression model was identified. MSU dissolution times were plotted against SU at different endpoints.

RESULTS

In 29 tophaceous gout patients, MSU volume reduced from baseline 10.94 ± 10.59 cm³ to 2.87 ± 5.27 cm³ on follow-up (p = .00). Dissolution rate had a stronger correlation with SU if calculated by compound method (Pearson's correlation coefficient r= -0.77, p = .00) and was independent of baseline MSU load. The ensuing dissolution model was logarithmic and explained real-life scenarios. When SU > 0.43 mmol/l, dissolution time approached infinity. It improved to 10-19 months at SU = 0.24 mmol/l. When SU approximated zero (as with pegloticase), dissolution flattened and still took 4-8 months.

CONCLUSION

MSU dissolution is better described as a logarithmic function of SU, which explains, predicts, and facilitates understanding of the dissolution process.

Systemic Urate Deposition: An Unrecognized Complication of Gout?

Gout, an inflammatory arthritis, affects over nine million people in the US with increasing prevalence. Some medical societies do not recommend treating gout unless it is recurrent. While soft tissue urate deposits (tophi), resultant bone erosions, and joint inflammation are frequently recognized in gout, urate crystal deposits in other sites have been thought to be rare. Recent diagnostic testing, such as dual energy computed tomography (DECT), has led to the recognition that urate deposits are not uncommon in other tissues including the vasculature. To understand the potential risks for untreated gout, we reviewed the literature on extra-articular urate deposition documented by autopsy, histopathology, surgery, and radiology, including the heart, blood vessels, kidney, spine, eye, skin, and gastrointestinal system. These studies extend the significance of gout beyond the rheumatologist and emphasize the need for physicians to follow the American College of Rheumatology guidelines to treat subjects with gout to a goal of achieving serum urate <6 mg/dl. Given the growing body of literature on extraarticular urate deposition, further studies and clinical trials are needed to determine the clinical consequences of systemic urate deposition, including if reducing cardiac and vascular urate deposits may provide a survival benefit for this at-risk population.