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-1β 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-1β 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

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.

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.

[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.

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.

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.

Pathogenesis and Clinical Management of Gouty Arthritis

Gout, the most common of the crystal arthritides is a result of disturbed uric acid metabolism and precipitation of urate crystals in extra cellular space of joints, periarticular tissue, bones and other organs. In the West, gout affects around 1% of adult men over 45 years of age. The estimated incidence being 0.6 to 2.1 per 1000 per year, with a prevalence of 9.5 to 13.5 per 1000 persons of all ages.1 The incidence of gout has been on rise globally; potentially attributable to recent shifts in diet, lifestyle, medical care, and increased longevity.2 Gout is three to four times more common in males than in pre-menopausal females; incidence in women increases after menopause and after the age of 60, approaches that in men.3 This update aims to highlight recent developments in understanding pathogenesis of gout along with current management strategies.

Clinical and epidemiological aspects of gout, a dysmetabolic disabling disorder

Gout is a disease caused by disturbances of uric acid metabolism and it manifests as rheumatic pain with various clinical and developmental issues, but without any major diagnosis problems; it might unfavorably interfere with other metabolisms, especially with carbohydrate and lipid metabolism that interact and erode each other.

AIMS

To provide clinical and laboratory data and to follow the development of gout in patients treated in the clinic.

MATERIAL AND METHODS

The study included 28 patients (25 male and 3 female patients) diagnosed with gout, admitted to the First Clinic of Rheumatology of the Clinical Rehabilitation Hospital Iasi during 2012-2013.

RESULTS AND DISCUSSION

A new diagnostic method, dual energy computed tomography, was effective in some selected cases of gout, as it may reveal uric acid crystals with specific densities in the damaged joints and periarticular soft tissues.

CONCLUSIONS

Gout is a disorder that occurs when the uric acid produced by the body is stored in the form of crystals in joints and/or soft tissues. In joints, uric acid crystals precipitate and cause inflammatory arthritis that leads to swelling, redness, heat, pain and joint functional impotence.

The last defence? Surgical aspects of gouty arthritis of hand and wrist

OBJECTIVE

To review the epidemiology, pathophysiology, clinical manifestations, diagnosis, and treatment of gouty arthritis of the hand and wrist, with a focus on the surgical aspects.

DATA SOURCES AND EXTRACTION

Electronic databases including MEDLINE, PubMed, and the Cochrane library were searched with the key words of "gouty arthritis", "hand", "wrist", and "surgical".

STUDY SELECTION

A total of 55 articles were selected for inclusion in this review.

DATA SYNTHESIS

There is no existing study for the overall prevalence of gout in Asia, though one study showed that it was 3.1% in Taiwan. Its pathophysiology entails hyperuricaemia, trauma, lower temperatures, and previous diseases. Gouty arthritis of hand and wrist presents as acute wrist pain, subcutaneous or peritendinous tophi, tenosynovitis, entrapment neuropathy, tendon rupture, or even bone destruction. Demonstration of negatively birefringent crystals in the absence of organisms and a normal white cell count in synovial fluid confirm the diagnosis. Medical treatment including non-steroidal anti-inflammatory drugs, colchicines, allopurinol, uricosuric agents, and lifestyle modifications remain the mainstay of treatment. Surgical treatment options for tophaceous gout involve decompression by aspiration, incision and drainage, tenosynovectomy, shaving procedures, and complex surgical approach. CONCLUSION. While medical treatment remains the mainstay of treatment for gouty arthritis of the hand and wrist, 5% of patients may not respond. In this group, surgery is often performed in advanced stages, but yields less-than-satisfactory outcomes. Gouty arthritis is difficult to treat when it starts to cause stiffness and deformities. Although more studies are needed to evaluate the outcomes, the authors suggest that one possible solution is pre-emptive surgery.

Gouty arthritis in a 15-year-old girl with Bartter's syndrome

A 15-year-old girl, a known case of Bartter's syndrome (BS) for 7 years, developed severe pain in her right knee and right and left ankle. Her older sister had BS and developed end-stage renal disease (ESRD) at the age of 14 years. Her serum uric acid was 12.6 mg/dL, 6 months ago, and 15.4 mg/dL in her recent lab data. Hyperuricemia and gouty arthritis are commonly seen in adults with BS, but to our knowledge there is no report of gouty arthritis in pediatric literature.

[Pathological mechanisms of gouty arthritis]

Gout is a disease caused by the deposition of monosodium urate monohydrate (MSU) crystals. Precise mechanisms underlying the initiation of acute gout, however, are not known. Recent investigations provided novel evidence in the pathology of acute gout. A number of studies indicated that MSU crystals can act as a "danger signal" which resembles exogenous adjuvants, and toll-like receptor(TLR)-mediated pathways and/or MyD88-dependent IL-1 receptor pathways are involved in acute gout. Up-regulation of the triggering receptor expressed on myeloid cells 1(TREM-1) in phagocytes by the stimulation with MSU crystals has been demonstrated. Furthermore, pathological significance of NALP 3 inflammasome in gout has been also demonstrated. These findings provide a new insight into the mechanisms underlying the initiation of MSU crystal-induced acute inflammation.

Gout and related morbid conditions: pharmacological and SPA therapy

Gouty arthritis is estimated to be the most frequent manifestation of inflammatory arthritis in men aged over 40. Hyperuricemia occurs because of both exogenous and genetic factors, which are particularly influential in some populations such as Taiwan aborigines. Current understanding of the disease etiopathogenesis, its clinical manifestations and the stages of its progression are presented here. The criteria for a correct diagnosis of the disease are also reported, pointing out how to distinguish gout from clinical events of different origin but with a very similar symptomatology. A distinction is made between the agents used to relieve the acute attack (colchicine, nonsteroidal anti-inflammatory drugs, corticosteroids) and those used with the purpose of correcting hyperuricemia and preventing recurrences and complications (allopurinol, uricosurics). Mecha-nisms of action, administration routes, doses, side effects and contraindications of every drug are described. Besides pharmacological therapy, the importance and the efficacy of spa therapy is underlined. Finally, perspectives opened by gene therapy are mentioned.

An update on the treatment options for gout and calcium pyrophosphate deposition

Gout and calcium pyrophosphate deposition disease are two common causes of inflammatory joint disease. Despite differences underlying their pathogenesis, their clinical presentation and treatment share some common features. Optimal treatment for both requires prompt resolution of acute synovitis, reduction of chronic joint damage and management of associated conditions. Available therapeutic interventions and future strategies are reviewed in this article.

Gouty arthritis. A primer on late-onset gout

Gouty arthritis, a common source of pain and disability, is the most common form of inflammatory arthritis affecting older people. The authors review the epidemiology and pathogenesis of hyperuricemia and gout, as well as the clinical forms of gouty arthritis. Gout is part of a clinical spectrum of conditions (obesity, diabetes mellitus, hyperlipidemia, coronary artery disease) and need for better patient education on management of these associated conditions is emphasized. The general algorithm of gout management is presented. Clinical particularities of gout presentation in older patients (increased incidence in women, polyarticular onset with hand involvement, earlier development of tophi, association with use of diuretics) are reviewed. Barriers against an optimal control of gout include lack of patient education, presence of comorbid conditions, particularly renal impairment, use of multiple drugs such as diuretics, and cognitive decline. Gout management in older adults remains unsatisfactory.

Signaling Events Involved in Macrophage Chemokine Expression in Response to Monosodium Urate Crystals

Chemokine production has been associated with leukocyte infiltration into the joint during gouty arthritis, and monosodium urate (MSU) crystals, the causative agent of this arthropathy, have been shown to modulate their expression. In the present study, we investigated the transductional mechanisms underlying this cellular regulation in the murine macrophage cell line B10R. We report that MSU crystals rapidly and transiently increase mRNA levels of various chemokines in a concentration-dependent manner. Examination of second messenger activation revealed that macrophage exposure to MSU crystals led to MEK1/2, ERK1/2, and inhibitory protein kappaBalpha phosphorylation as well as to NF-kappaB and AP-1 nuclear translocation. Of interest, specific blockage of the ERK1/2 pathway drastically reduced up-modulation of MSU crystal-mediated chemokine production and activation of nuclear factors. Similarly, selective inhibition of NF-kappaB suppressed NF-kappaB DNA binding activity and the induction of all chemokine transcripts. These findings indicate that ERK1/2-dependent signals seem to be required for AP-1 and NF-kappaB activation and subsequent mRNA expression of the various macrophage chemokines. In addition, transcription and stability assays performed in presence of actinomycin D showed that MSU crystal-mediated MIP-1beta mRNA up-regulation resulted solely from transcriptional control, whereas that of MIP-1alpha, MIP-2, and MCP-1 was due to both gene transcription activation and mRNA posttranscriptional stabilization. Overall, the results of this study help to define the molecular events that govern macrophage chemokine regulation in response to MSU crystals, which is of paramount importance to better understand, and eventually to tame, the inflammatory response during acute gout.

A rare and asymptomatic case of mitral valve tophus associated with severe gouty tophaceous arthritis

Gouty arthritis is characterized by the deposition of monosodium urate crystals in the joints and soft tissues. Clinical manifestations include acute and chronic arthritis and tophaceous deposits. Chronic tophaceous gout has become less common since the introduction of the pharmacological treatment. Moreover, cardiac valve gouty tophi have been very rarely reported.

Clinical manifestations of patients with hyperuricemia

OBJECTIVE

To study the clinical manifestations of patients with hyperuricemia in King Chulalongkorn Memorial Hospital.

METHOD

A cross sectional study of 188 hyperuricemic patients was done at King Chulalongkorn Memorial Hospital. History, physical examination, and blood samples were drawn to assess complete blood count (CBC), blood urea nitrogen (BUN), creatinine (Cr), liver function test (LFT), and serum uric acid in all patients.

RESULTS

Most of the patients (92%) were male, more than 50 years old (69%), the mean age of the patients was 56.7 +/- 12.1 years old. All of the female patients were more than 50 years old. Symptomatic hyperuricemia was found in 93%, the mean duration of symptoms was 63.2 +/- 66.3 months. The mean of the serum uric acid level was 10.0 +/- 2.9 mg/dl. Associated diseases were found in 46% of the patients, and 30% of these patients had more than one disease. Hypertension was the most common followed infrequency by dyslipidemia, diabetes mellitus, ischemic heart disease, and chronic obstructive pulmonary disease consecutively. Renal impairment was detected in about one-third of the patients.

CONCLUSION

This study shows that hyperuricemia is common in elderly, male patients. Associated diseases and renal impairment can befoundfrequently, and the patients should be monitored.