NLRP3 inflammasome inhibitor cucurbitacin B suppresses gout arthritis in mice.

Gouty arthritis is a common inflammatory disease characterized by monosodium urate (MSU) crystal-induced nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome activation with upregulated caspase 1 protease and IL-1ß in macrophages. Cucurbitacin B (CuB) is a tetracyclic triterpene that possesses a potential anti-inflammatory activity. However, the immunomodulatory and anti-inflammatory effects of CuB on gout have not been well characterized. Therefore, the purpose of the present study was to determine whether CuB exhibits anti-inflammatory effects on gout and to analyze the underlying molecular mechanism. We examined the effects of CuB on various stimuli-activated bone marrow-derived macrophages (BMDMs) and in a mouse model with MSU-induced acute gouty arthritis. Our results demonstrated that CuB effectively suppressed multiple stimuli-activated IL-1ß secretion by interrupting NLRP3 inflammasome complex formation, inhibiting NLRP3 inflammasome activation and suppressing key enzymes of glycolysis in macrophages. Consistent with this, CuB pretreatment also ameliorated MSU-induced arthritis in vivo models of gout arthritis, manifested by reduced foot swelling and inflammatory cell infiltration. Taken together, our data provide the evidence that CuB is an NLRP3 inflammasome inhibitor with therapeutic potential for treating NLRP3 inflammasome-mediated diseases, especially gouty arthritis.

Establishment of a clinical diagnostic model for gouty arthritis based on the serum biochemical profile: A case-control study.

ABSTRACT: The disease progression of gouty arthritis (GA) is relatively clear, with the 4 stages of hyperuricemia (HUA), acute gouty arthritis (AGA), gouty arthritis during the intermittent period (GIP), and chronic gouty arthritis (CGA). This paper attempts to construct a clinical diagnostic model based on blood routine test data, in order to avoid the need for bursa fluid examination and other tedious steps, and at the same time to predict the development direction of GA.Serum samples from 579 subjects were collected within 3 years in this study and were divided into a training set (n = 379) and validation set (n = 200). After a series of multivariate statistical analyses, the serum biochemical profile was obtained, which could effectively distinguish different stages of GA. A clinical diagnosis model based on the biochemical index of the training set was established to maximize the probability of the stage as a diagnosis, and the serum biochemical data from 200 patients were used for validation.The total area under the curve (AUC) of the clinical diagnostic model was 0.9534, and the AUCs of the 5 models were 0.9814 (Control), 0.9288 (HUA), 0.9752 (AGA), 0.9056 (GIP), and 0.9759 (CGA). The kappa coefficient of the clinical diagnostic model was 0.80.This clinical diagnostic model could be applied clinically and in research to improve the accuracy of the identification of the different stages of GA. Meanwhile, the serum biochemical profile revealed by this study could be used to assist the clinical diagnosis and prediction of GA.

Role of T cells in the pathogenesis and treatment of gout.

Though macrophages and neutrophils are considered to be the principal immune cells involved in gout inflammation, recent studies highlight an emerging role of T cell subsets in the pathogenesis of gout. Some studies found that abnormal functions of several T cell subsets and aberrant expressions of their signature cytokines existed in gouty arthritis. Additionally, recent studies also suggested that therapeutic strategies by targeting pro-inflammatory T cell subsets or their related cytokines could ameliorate monosodium urate (MSU) crystals-induced arthritis in mice. The important role of T cells in gouty arthritis may provide some explanation for the absence of acute gout attacks among individuals with severe hyperuricemia or clinical evidence of MSU crystals deposition. Nevertheless, the molecular mechanisms underlying the role of those T cell subsets in gouty arthritis and their role in the initiation, progression and resolution of gouty arthritis are largely elusive, which need to be elaborated in future research. Uncovering the role of those T cell subsets in gout may transform our understanding of gout and facilitate new promising preventive or therapeutic strategies for gouty arthritis.

[Gout arthritis: Pathogenesis, diagnostics and treatment]. / Die Gichtarthritis: Pathogenese, Diagnostik und Behandlung.

The initial presentation of gouty arthritis can be a dramatic event. Chronic gout may lead to the destruction of joints, invalidity and increased mortality. The incidence of this disorder is high, despite effective therapeutic measures. The treatment of refractory cases may be a challenge to the general practitioner and the specialist alike. The article presented here summarizes the current state of diagnostics and treatment of acute and chronic gout.

Imaging of gout: findings and pitfalls. A pictorial review.

Gout is the most common crystal arthropathy, accounting for up to 5% of all arthritis. The hallmark of the disease is hyperuricemia with the subsequent deposition of monosodium urate (MSU) crystals in the intra- and extra-articular soft tissues and bones, leading to inflammation of these tissues. Recurrent intermittent flares can result in chronic gouty arthritis leading to cartilage and bone destruction. The most sensitive and specific imaging methods for diagnosing acute gout are ultrasound and dual energy computed tomography (DECT). In the chronic or tophaceous gout, imaging may depict tophi and their local destructive effect on surrounding tissues with characteristic findings on radiographs. In this pictorial review the imaging features of acute and chronic gout on radiographs, ultrasound, and DECT are presented, as well as imaging pitfalls that one needs to be aware.

Caspase-11 Mediates Neutrophil Chemotaxis and Extracellular Trap Formation During Acute Gouty Arthritis Through Alteration of Cofilin Phosphorylation.

Gout is characterized by attacks of arthritis with hyperuricemia and monosodium urate (MSU) crystal-induced inflammation within joints. Innate immune responses are the primary drivers for tissue destruction and inflammation in gout. MSU crystals engage the Nlrp3 inflammasome, leading to the activation of caspase-1 and production of IL-1ß and IL-18 within gout-affected joints, promoting the influx of neutrophils and monocytes. Here, we show that caspase-11-/- mice and their derived macrophages produce significantly reduced levels of gout-specific cytokines including IL-1ß, TNFα, IL-6, and KC, while others like IFNγ and IL-12p70 are not altered. IL-1ß induces the expression of caspase-11 in an IL-1 receptor-dependent manner in macrophages contributing to the priming of macrophages during sterile inflammation. The absence of caspase-11 reduced the ability of macrophages and neutrophils to migrate in response to exogenously injected KC in vivo. Notably, in vitro, caspase-11-/- neutrophils displayed random migration in response to a KC gradient when compared to their WT counterparts. This phenotype was associated with altered cofilin phosphorylation. Unlike their wild-type counterparts, caspase-11-/- neutrophils also failed to produce neutrophil extracellular traps (NETs) when treated with MSU. Together, this is the first report demonstrating that caspase-11 promotes neutrophil directional trafficking and function in an acute model of gout. Caspase-11 also governs the production of inflammasome-dependent and -independent cytokines from macrophages. Our results offer new, previously unrecognized functions for caspase-11 in macrophages and neutrophils that may apply to other neutrophil-mediated disease conditions besides gout.

Sirt1 inhibits gouty arthritis via activating PPARγ.

OBJECTIVE: To identify the effects of Sirtuin 1 (Sirt1) on gouty arthritis and investigate the underlying mechanisms. METHODS: A gouty arthritis model was established by intra-articular injection of monosodium urate (MSU, 1 mg) crystal solution into the left foot pad of C57BL/6 mice. After pretreating the gouty arthritis mice with intra-articular injection of Sirt1 agonist (Resveratrol, RSV, 20 mg/kg) or peroxisome proliferator-activated receptor γ (PPARγ) inhibitor (T0070907, 1 mg/kg), the degree of joint inflammation of the gouty arthritis mice was evaluated by clinical integration of joint inflammation and hematoxylin and eosin (H&E) staining. The mRNA expression of Sirt1 and PPARγ were determined by real-time polymerase chain reaction (PCR). The expression profiling of inflammatory cytokines and chemokines in mouse joint tissues were determined by multi-factor assay kits. Peritoneal macrophages were isolated from mice and tested the effects of RSV and/or PPARγ on pro-inflammatory cytokines secretion by PCR. RESULTS: Sirt1 agonist significantly suppressed the onset of gouty arthritis induced by MSU and reduced the infiltration of inflammatory cells in the joints. Sirt1 agonist significantly promoted the expression of PPARγ, while decreased the expression of interleukin (IL)-1ß, IL-1α, IL-6, interferon-γ (IFN-γ), monocyte chemotactic protein 1(MCP-1), tumor necrosis factor a (TNF-α), and chemokines (CXCL-1, CXCL-5, CCL-22) induced by MSU in joint tissues. After blocking PPARγ with T0070907 or by siRNA, the anti-inflammatory effect of Sirt1 agonist on gouty arthritis disappeared and the expression of pro-inflammatory molecules were not significantly reduced. CONCLUSIONS: Sirt1 may control the acute onset of gouty arthritis in mice by inhibiting the infiltration of inflammatory cells and the secretion of pro-inflammatory molecules through PPARγ. Key Points • Sirt1 and its activator, RSV, attenuate the severity of gouty arthritis in mice. • Sirt1 inhibits the infiltration of inflammatory cells and the secretion of pro-inflammatory molecules in MSU-induced arthritis. • Sirt1 inhibits inflammation partially dependent on PPARγ.

Crystal-Induced Arthritis After Total Ankle Arthroplasty.

The causes of late-onset pain after total ankle replacement (TAR) are various, and include infection, subsidence, polyethylene spacer failure, osteolysis, and wear. There are few reports of late-onset pain caused by gouty attacks after total knee and hip arthroplasty. In addition, no research has reported gouty attacks after total ankle arthroplasty. Therefore, we report a case of a gouty attack after total ankle replacement. A 43-year-old man presented with pain after total ankle arthroplasty performed 5 years previously. We found a white-yellow crystalline deposit within the synovial tissue during ankle arthroscopy, confirmed by histologic examination.

Hyperuricemia, urine uric excretion, and associated complications in thalassemia patients.

Thalassemia patients have a high cell turnover rate due to chronic hemolysis and ineffective erythropoiesis; therefore, hyperuricemia is anticipated. This study aimed to identify the prevalence of hyperuricemia, gout and nephrolithiasis, conditions associated with serum uric acid (SUA), and urine uric acid excretion (UUA) in thalassemia patients. This was a cross-sectional study in patients aged 15 years or older at Chiang Mai University Hospital. All patients had blood and 24-h urine collection test. We enrolled 112 thalassemia patients in which 67.0% were female, 64.3% had beta thalassemia/Hb E, 76.8% were transfusion dependent, and 59.8% were post splenectomy. The median age was 29 (16-58) years. Mean SUA was 6.7 ± 2.0 mg/dl and hyperuricemia (SUA > 6.8 mg/dl) was found in 47 cases (45.2%). Intact spleen (ORs 4.3, 95%CI 1.55-12.50, p = 0.01) and lower FEuric (ORs 2.08, 95%CI 1.35-3.33, p < 0.01) were associated with hyperuricemia significantly. Seven (6.3%) had gouty arthritis and nine (8%) had microscopic hematuria, one case being confirmed nephrolithiasis. The mean UUA excretion was 981.3 ± 335.0 mg/day and UUA hyperexcretion (> 700 mg/24 h) was found in 83.3%. UUA hyperexcretion patients had renal hyperfiltration 46%, glomerular dysfunction 84%, and tubular dysfunction 7.7%. From our study, hyperuricemia was found in approximately 40% of thalassemia patients but gouty arthritis occurred only in few patients (6%). This may be explained by urinary uric hyperexcretion which is found in over 80%. The significant risk factors for hyperuricemia were intact spleen and lower fraction excretion of uric acid.

[A case of gout secondary to primary myelofibrosis].

A 52-year-old man was referred to our department with a 2-year history of polyarthritis. He was diagnosed as gout due to acute arthritis of bilateral feet dorsum 2 years ago,but he didn't receive any standard treatment. 1 year ago,there were more and more joints evolved during the gout attack, and many subcutaneous nodules occurred. When he presented to our clinic 1 month ago,the urate acid level was as high as 715 µmol/L. Moreover, we could find bone erosion in the X rays of his hand and foot,as well as synovitis,double contour sign and tophus on the ultrasound examination. The diagnosis of gout was clearly and definitely. However, he had leukocytosis and thrombocytosis for 4 years in the past history, and the urate acid level was only 400 µmol/L at that time. He also had well-controlled hypertension. The family history was unremarkable. Furthermore, we found megalosplenia on his physical examination. The bone marrow examination showed myelofibrosis and JAK2 V617F gene was positive. He was diagnosed as primary myelofibrosis and treated with interferon-α, together with urate acid-lowing therapy (febuxostat 60 mg once daily). Following-up for 1 year,the dosage of febuxostat decreased to 40 mg once daily, and the patient didn't have gout attack again, some of the tophus diminished, and the urate acid level ranged from 400 to 500 µmol/L. Gout is a common disease in clinical practice,usually combined with metabolic syndrome,chronic renal failure and specific drugs using (diuretic and calcineurin inhibitors). However,it is relatively rare to see gout associated with myeloproliferative diseases, including polycythemia vera, primary thrombocythemia, primary myelofibrosis and chronic myelocytic leukemia. In these diseases, the turnover of nucleic acids is greatly augmented, and an excess of purine metabolites, including uric acid, is released. In the natural course of gout, the appearance of tophus from the first onset of arthritis usually takes several years. This patient only had one traditional risk factor, but his urate acid level was remarkably high and he developed tophus in a short term. After treatment of primary myelofibrosis, the symptom of gout partially alleviated. Careful physical examination and medical history taking lead to the diagnosis of secondary gout, which should be reminded in the daily practice.

Clinical manifestations and molecular aspects of phosphoribosylpyrophosphate synthetase superactivity in females.

Objectives: Phosphoribosylpyrophosphate synthetase (PRPS1) superactivity is an X-linked disorder characterized by urate overproduction Online Mendelian Inheritance in Man (OMIM) gene reference 300661. This condition is thought to rarely affect women, and when it does, the clinical presentation is mild. We describe a 16-year-old African American female who developed progressive tophi, nephrolithiasis and acute kidney failure due to urate overproduction. Family history included a mother with tophaceous gout who developed end-stage kidney disease due to nephrolithiasis and an affected sister with polyarticular gout. The main aim of this study was to describe the clinical manifestations of PRPS1 superactivity in women. Methods: Whole exome sequencing was performed in affected females and their fathers. Results: Mutational analysis revealed a new c.520 G > A (p.G174R) mutation in the PRPS1 gene. The mutation resulted in decreased PRPS1 inhibition by ADP. Conclusion: Clinical findings in previously reported females with PRPS1 superactivity showed a high clinical penetrance of this disorder with a mean serum urate level of 8.5 (4.1) mg/dl [506 (247) µmol/l] and a high prevalence of gout. These findings indicate that all women in families with PRPS1 superactivity should be genetically screened for a mutation (for clinical management and genetic counselling). In addition, women with tophaceous gout, gout presenting in childhood, or a strong family history of severe gout should be considered for PRPS1 mutational analysis.

Joint Clinical Consensus Statement of the American College of Foot and Ankle Surgeons® and the American Association of Nurse Practitioners®: Etiology, Diagnosis, and Treatment Consensus for Gouty Arthritis of the Foot and Ankle.

Gout is a condition that commonly affects the foot and ankle, and practitioners who treat these structures should be aware of the methods to diagnose and treat this form of arthritis. Practitioners also need to recognize extra-articular manifestations of the disease. Although the acutely red, hot, swollen joint is a common presentation, chronic tophaceous gout can be associated with pain, nodule formation, and cutaneous compromise. Since the underlying causes that lead to excessive monosodium urate deposition may be treatable, early and accurate diagnosis can be very beneficial and may even prevent articular degeneration.

Spinal tophaceous gout presenting in a young adult without pain.

A 26-year-old man with a medical history of gout and morbid obesity presented with a 7-day history of decreased sensation to light touch and temperature from the feet to the level of the nipples. He also noted incomplete voiding. Laboratory investigations showed an elevated serum uric acid level (10.4 mg/dL, reference range: 3.8-8.7 mg/dL) as well as negative rapid plasma reagin and rheumatoid factor. MRI showed inflammatory changes on multiple spinal levels. Laminectomy was performed, with follow-up biopsy revealing multiple multinucleated giant cells and monosodium urate (MSU) crystals. He was ultimately diagnosed with spinal gout. Patient's symptoms did not resolve immediately after surgery. Yet with the administration of intravenous glucocorticoids and a course of non-steroidal anti-inflammatory drugs, he slowly regained sensation, leaving the hospital with complete resolution of symptoms.

Omega-3-carboxylic acids provide efficacious anti-inflammatory activity in models of crystal-mediated inflammation.

This study assesses the efficacy and exposure-response relationship of omega-3-carboxylic acids (OM-3 CA) in models of crystal-based inflammation. Human THP-1 macrophages and primary peripheral blood mononuclear cells exposed to multiple inflammatory crystal types were used to determine the anti-inflammatory potential of omega-3 (OM-3) fatty acids in vitro. Anti-inflammatory effects of OM-3 CA in vivo were tested in rat monosodium urate (MSU) crystal air pouch and rat knee intra-articular MSU injection models. Acute treatment with the OM-3 fatty acid docosahexaenoic acid suppressed MSU-, cholesterol crystal-, and calcium pyrophosphate crystal-mediated interleukin-1ß (IL-1ß) production in vitro. In vivo, OM-3 CA dose-dependently reduced crystal-mediated cell migration, exudate volume, and levels of IL-1ß and prostaglandin E2. Following intra-articular injection of MSU, treatment with OM-3-CA (1 mL/kg) and indomethacin (1 mg/kg) resulted in similar mean reductions in pain (23% and 41%, respectively) and swelling (58% and 50%, respectively), compared with controls. Additionally, in complex formulations of OM-3 fatty acids, high levels of palmitic acid could reduce the in vivo effect on crystal-mediated IL-1ß elevation. OM-3 CA has a broadly efficacious anti-inflammatory effect with a strong exposure-response relationship that could be beneficial in prevention and treatment of crystal arthritis, with potential applications in other IL-1ß-mediated diseases.

Association between acute gouty arthritis and meteorological factors: An ecological study using a systematic review and meta-analysis.

OBJECTIVES: The aims of this study were as follows: (1) to analyze the literature systematically regarding the seasonal and monthly variation of the occurrence of episodes of acute gouty arthritis, and (2) to investigate the relationship between the occurrence of episodes of acute gouty arthritis and meteorological parameters. METHODS: The present authors systematically reviewed databases for articles published before November 2015. Studies with quantitative data on episodes of acute gouty arthritis by months and/or seasons were included. Meteorological data such as the highest temperature, lowest temperature, diurnal temperature range, change in mean temperature between neighboring days, relative humidity and wind speed for the geographic place(s), and study period where and when each study took place were obtained from meteorological websites. RESULTS: Ten studies published between 1920 and 2015 were included. A meta-analysis by season showed that acute gouty arthritis occurred significantly more frequently in spring than in other seasons. Analysis by month showed an increase in episodes of acute gouty arthritis from March to July, being the highest in July. The trend reversed, and episodes of acute gouty arthritis started decreasing from July to September, being the lowest in September. The change in mean temperature between neighboring days was the only meteorological parameter that was significantly correlated with the number of monthly episodes of acute gouty arthritis. CONCLUSIONS: Acute gouty arthritis seems to develop more frequently during the period in which the temperature increases significantly between neighboring days: spring by season and between March and July by month in the northern hemisphere.

[Evidence-based recommendations for diagnostics and treatment of gouty arthritis in the specialist sector : S2e guidelines of the German Society of Rheumatology in cooperation with the AWMF]. / Evidenzbasierte Empfehlung zur Diagnostik und Therapie der Gichtarthritis im fachärztlichen Sektor : S2e-Leitlinie der Deutschen Gesellschaft für Rheumatologie (DGRh) in Kooperation mit der AWMF.

Due to the increasing prevalence of gout, particularly in old age, the disease is becoming of increasing importance in Germany. Gout is one of the most common forms of recurrent inflammatory arthritis and is induced by the deposition of monosodium urate crystals in synovial fluid and other tissues. The principal goals of therapy in chronic gout are the symptomatic treatment of the acute joint inflammation and the causal treatment of the underlying metabolic cause, the hyperuricemia. Only a consistent and permanent reduction of the serum uric acid level ultimately results in an efficient avoidance of further gout attacks and therefore the prevention of structural damage. Due to an often inadequate treatment of gout, the target of healing the disease is often not achieved. A correct and timely diagnosis and adequate assessment of comorbidities associated with gout are, however, of substantial importance for patient and physician to achieve remission of the disease. In order to create a solid basis for a timely and effective treatment of affected patients, in 2016 the German Society of Rheumatology (DGRh) initiated the development of S2e guidelines on gouty arthritis for specialists. This article summarizes these S2e guidelines on the management of gouty arthritis in the specialist sector.

MUSCULOSKELETAL IMPAIRMENT IN PRYMARY HYPOTHYROIDISM.

This article contains bibliographical data concerning the rheumatic clinical manifestations in hypothyroidism: polyarthralgias, lack of recent skill of fine movements of the hands, carpal tunnel syndrome or tarsal, degenerative arthropathy or acute type (gout, chondrocalcinosis), adhesive capsulitis (frozen shoulder syndrome), generalized muscular stiffness, hypothyroid myopathy, secondary osteoarthritis, Dupuytren's contracture, "trigger finger" (also called as stenosing tenosynovitis or trigger thumb) etc. and data on the short history, epidemiology, of these disorders. Review include 60 bibliographical sources.