Management of treatment resistant inflammation of acute on chronic tophaceous gout with anakinra

Effectiveness and safety of anakinra in gouty arthritis: A case series and review of the literature

Background

Gout is the most common type of inflammatory arthritis. Nonsteroidal anti-inflammatory drugs, corticosteroids, and colchicine are the first-line agents, although they are contraindicated in many patients. Blockade of IL-1 with anakinra can be an alternative.

Objective

To present a case series of 10 difficult-to-treat gout patients treated with anakinra and perform a scoping review of the effectiveness and safety of anakinra in gout patients.

Methods

A total of 1,519 citations were screened. The reviewers ran a two-stage screening process by title/abstract and full-text reading. Thirty-eight articles finally met the selection criteria and were included for data extraction and synthesis. Experience in difficult-to treat and complex clinical scenarios, such as active infection, hemodialysis, and transplantation, were specifically described.

Results

The study sample comprised 551 patients, from whom 648 flares were finally analyzed. The mean age was 57.9 years, and 82.9% were men. The clinical presentation was polyarticular in 47.5% and tophaceous in 66.9%. Sixty-five patients with an active infection, 41 transplanted patients and 14 in haemodyalisis treated with anakinra are described. More than half of the patients had >1 associated comorbidity. Anakinra was effective both for flares (94%) and for long-term treatment (91%) and well tolerated. In the case of flares, 34 (6.7%) adverse effects were registered. Adverse events were more prevalent in long-term treatment.

Conclusion

Anakinra was effective and safe for management of gout flares in difficult-to-treat patients. It has been used in multiple complex scenarios, such as active infections, dialysis, transplantation, chronic kidney disease, and polyarticular gout. Anakinra has also proven effective as long-term treatment, although there are more concerns about its safety.

Autoinflammatory manifestations in adult patients

Autoinflammatory diseases represent a family of immune-mediated conditions characterized by the unchecked activation of innate immunity. These conditions share common clinical features such as recurrent fever, inflammatory arthritis, and elevation of acute phase reactants, in the absence of an identified infectious etiology, generally without detectable serum autoantibodies, with variable response to glucocorticoids and in some cases colchicine, which represented the mainstay of treatment until cytokine blockade therapies became available. The first autoinflammatory diseases to be described were monogenic disorders caused by missense mutations in inflammasome components and were recognized predominantly during childhood or early adulthood. However, the progress of genetic analyses and a more detailed immunological phenotyping capacity led to the discovery a wide spectrum of diseases, often becoming manifest or being diagnosed in the adult population. The beneficial role of targeting hyperinflammation via interleukin 1 in complex non-immune-mediated diseases is a field of growing clinical interest. We provide an overview of the autoinflammatory diseases of interest to physicians treating adult patients and to analyze the contribution of hyperinflammation in non-immune-mediated diseases; the result is intended to provide a roadmap to orient scientists and clinicians in this broad area.

Treatment Guidelines in Gout

The range of drug treatment options to treat acute and chronic gout has changed dramatically over the last 20 years. Yet, there is general consensus that drug therapy selection, dosing and dose titration, of both traditional and novel agents is far from optimally delivered in clinical practice. Updated guidelines disseminated in the last 5 years, from the American College of Physicians, the European League Against Rheumatism, and the American College of Rheumatology, provide clear guidance to the medical community on how and when to optimally integrate these therapeutic options into practice to improve the medical management of gout.

Natural Products as a Novel Therapeutic Strategy for NLRP3 Inflammasome-Mediated Gout

Gout is the most common form of inflammatory arthritis. It occurs when monosodium urate crystals (MSU) are deposited within joints due to hyperuricemia and persistent elevations of serum uric acid levels. Traditional gout treatment such as urate-lowering therapy is difficult to continue for a long period of time due to the risk of side effects. Recent studies have shown that the modulation of MSU-induced inflammatory responses is dependent on the inflammatory cytokine IL-1β, which has a central role in a chain of processes involving multiple cytokines and mediators. In this regard, the NLRP3 inflammasome is known to play a crucial part and thus has been proposed as a novel target in the treatment for gout. However, the biochemical mechanism for NLRP3 inflammasome activation has not yet been clearly elucidated. Therefore, this report can provide an overview of natural extractions targeted to prevent or treat NLRP3 inflammasome-mediated gout in the MSU-induced gout model. In addition, the research and development of such natural products are suggested as a potential strategy in the treatment of gout.

Efficacy and safety of gout flare prophylaxis and therapy use in people with chronic kidney disease: a Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN)-initiated literature review

Gout flare prophylaxis and therapy use in people with underlying chronic kidney disease (CKD) is challenging, given limited treatment options and risk of worsening renal function with inappropriate treatment dosing. This literature review aimed to describe the current literature on the efficacy and safety of gout flare prophylaxis and therapy use in people with CKD stages 3-5. A literature search via PubMed, the Cochrane Library, and EMBASE was performed from 1 January 1959 to 31 January 2018. Inclusion criteria were studies with people with gout and renal impairment (i.e. estimated glomerular filtration rate (eGFR) or creatinine clearance (CrCl) < 60 ml/min/1.73 m²), and with exposure to colchicine, interleukin-1 inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), and glucocorticoids. All study designs were included. A total of 33 studies with efficacy and/or safety analysis stratified by renal function were reviewed-colchicine (n = 20), anakinra (n = 7), canakinumab (n = 1), NSAIDs (n = 3), and glucocorticoids (n = 2). A total of 58 studies reported these primary outcomes without renal function stratification-colchicine (n = 29), anakinra (n = 10), canakinumab (n = 6), rilonacept (n = 2), NSAIDs (n = 1), and glucocorticoids (n = 10). Most clinical trials excluded study participants with severe CKD (i.e. eGFR or CrCl of < 30 mL/min/1.73 m²). Information on the efficacy and safety outcomes of gout flare prophylaxis and therapy use stratified by renal function is lacking. Clinical trial results cannot be extrapolated for those with advanced CKD. Where possible, current and future gout flare studies should include patients with CKD and with study outcomes reported based on renal function and using standardised gout flare definition.

Off-label use of anti-IL-1 drugs in rheumatic diseases

Interleukin-1 (IL-1) plays a key role in the pathogenesis of different rheumatic diseases. There are now several agents available on the market capable of blocking IL-1. The proven effectiveness and excellent safety of these drugs makes them a possible therapeutic option in the treatment of IL-1 driven diseases, when previous therapies are contraindicated or ineffective. This article discusses the European wide off-label use of these drugs for the treatment of rheumatic diseases.

NLRP3 inflammasome inhibitor INF39 attenuated NLRP3 assembly in macrophages

INF39 is a nontoxic, irreversible, acrylate-based NLRP3 inhibitor and a further optimization of ethyl 2-((2-chlorophenyl) hydroxyl) methyl) acrylate (INF4E). However, the detail mechanism and the direct target of its anti-inflammatory activity is not clear. Here, we show that INF39 is a specific inhibitor for NLRP3 inflammasome activation. INF39 specifically suppresses NLRP3 activation but not the NLRC4 or AIM2 inflammasomes. INF39 has no effect on K⁺ efflux, ROS generation or mitochondrial membrane potential, which are the upstream events of NLRP3 inflammasome activation. In addition, INF39 has no direct inhibitory effect on GSDMD, which is the downstream event of inflammasomes. More importantly, INF39 inhibits the interaction of NEK7-NLRP3, and subsequently inhibits interaction of NLRP3-NLRP3, NLRP3-ASC, ASC oligomerization and speckle formation. Altogether, our study unveils a deeper anti-inflammatory mechanism for INF39 and suggests it could serve as a lead for developing novel therapeutics combating NLRP3-driven diseases.

[Results of the systematic literature search as basis for the "Evidence-based treatment recommendations for familial Mediterranean fever patients with insufficient response or intolerability to colchicine" of the Society for Pediatric and Adolescent Rheumatology and the German Society for Rheumatology]

BACKGROUND

Familial Mediterranean fever (FMF) is a genetic disease of childhood and adulthood which is relatively rare in Germany. It is characterized by recurrent febrile attacks, peritonitis, pleuritis and arthritis. The established treatment with colchicine is effective and well-tolerated by most patients; however, some patients do not adequately respond or do not tolerate this treatment. Biologics can be considered for some of these patients. The Society for Pediatric and Adolescent Rheumatology (GKJR) and the German Society for Rheumatology (DGRh) have agreed to develop joint recommendations for this specific clinical situation.

AIM

Implementation of a systematic literature search (SLR) on the basis of the EULAR recommendations published in 2016 as the foundation for the development of evidence-based treatment recommendations for FMF patients with insufficient response or intolerance to colchicine.

METHODS

The SLR was performed using references from various databases as an update of the SLR carried out by EULAR up to 2014, whereby all articles must have been published between 1 January 2015 and 31 December 2017. The Rayyan abstract tool for the preselection and the classification of the Oxford Centre for Evidence Based Medicine 2009 were used for the preparation of the evidence tables.

RESULTS

The search yielded 360 hits and after duplicate matching 263. A total of 88 publications were included (34%) and 102 excluded (39%), a review of the full publication was necessary for a further 73 (28%) and 43 were discussed more intensively. Finally, 64 publications (24%) remained. A total of 4 case-control studies, 31 cohort studies, 8 case series, 7 controlled studies (including 5 abstracts), 10 reviews, 4 meta-analyses and systematic reviews were accepted.

DISCUSSION

The SLR was carried out in a scientifically accurate and transparent manner according to international standards. The SLR proved to be a good basis for a consensus on the 5 overarching principles and the 10 recommendations, so that the joint activity of the GKJR and DGRh was successfully and even promptly concluded. The recommendations are a solid basis for treating patients of all ages with FMF. The explanations on the problem of colchicine resistance play an important role here.

NLRP3 Inflammasome in Inflammation and Metabolism: Identifying Novel Roles in Postburn Adipose Dysfunction

Inflammasomes are multiprotein complexes that respond to pathogen or host associated damage markers, leading to caspase-1 maturation and processing of pro-inflammatory cytokines. Initially, inflammasomes were implicated primarily in inflammatory and infectious conditions. However, increasing evidence demonstrates broader roles beyond inflammation, including regulation of adipose tissue metabolism after burns. Here, we conducted a search for articles on PubMed, Web of Science, Embase, Scopus, and UpToDate with applied search strategies including a combination of "burns," "trauma," "(NLRP3) inflammasome," "metabolic conditions," "white adipose tissue," "macrophages," "browning," and "lipolysis" and included papers from 2000 to 2020. We discuss unexpected roles for NLRP3, the most characterized inflammasome to date, as a key metabolic driver in a variety of conditions. In particular, we highlight the function of NLRP3 inflammasome in burn trauma, which is characterized by both hyperinflammation and hypermetabolism. We identify a critical part for NLRP3 activation in macrophage dynamics and delineate a novel role in postburn white adipose tissue remodeling, a pathological response associated with hypermetabolism and poor clinical outcomes. Mechanistically, how inflammation and inflammasome activation is linked to postburn hypermetabolism is a novel concept to contemplate, and herein we provide evidence of an immunometabolic crosstalk between adipocytes and infiltrating macrophages.

Ginsenoside Rg3 suppresses the NLRP3 inflammasome activation through inhibition of its assembly

Ginsenoside Rg3 is one of the main constituents of Panax ginseng. Compelling evidence has demonstrated that ginsenoside Rg3 is capable of inhibiting inflammation. However, the mechanism mediating its anti-inflammatory effects remain unclear. Here we show that ginsenoside Rg3 blocks IL-1β secretion and caspase-1 activation through inhibiting LPS priming and the NLRP3 inflammasome activation in human and mouse macrophages. Rg3 specifically inhibits activation of NLRP3 but not the NLRC4 or AIM2 inflammasomes. In addition, Rg3 has no effect on upstream regulation of NLRP3 inflammasome, such as K⁺ efflux, ROS production, or mitochondrial membrane potential. Mechanistically, Rg3 abrogates NEK7-NLRP3 interaction, and subsequently inhibits NLRP3-ASC interaction, ASC oligomerization, and speckle formation. More importantly, Rg3 can reduce IL-1β secretion induced by LPS in mice and protect mice from lethal endotoxic shock. Thus, our findings reveal an anti-inflammatory mechanism for Rg3 and suggest its potential use in NLRP3-driven diseases.

Autoinflammation: Lessons from the study of familial Mediterranean fever

Autoinflammatory disorders represent a heterogeneous group of systemic inflammatory diseases caused by genetic or acquired defects in key components of the innate immunity. Familial Mediterranean fever (FMF) is the most common among the other clinical phenotypes of the rare hereditary periodic fevers (HPFs) syndromes. FMF is associated with mutations in the MEFV gene encoding pyrin and is characterized by recurrent, often stress-provoked attacks of fever and serositis, but sometimes also by chronic subclinical inflammation. FMF is prevalent in Greece and other countries of the eastern Mediterranean region. Over the last 17 years, our group has focused on FMF as a model suitable for the research on innate immunity and particularly the role of neutrophils. Therefore, the study of Greek patients with FMF has yielded lessons across several levels: the epidemiology of the disease in Greece, the spectrum of its clinical manifestations and potential overlaps with other idiopathic inflammatory conditions, the demonstration of its rather complex and heterogeneous genetic background and the suggestion of a novel mechanism involved in the crosstalk between environmental stress and inflammation. Mechanistically, during FMF attack, neutrophils release chromatin structures called neutrophil extracellular traps (NETs), which are decorated with bioactive IL-1β. REDD1 (regulated in development and DNA damage responses 1), that encodes a stress-related mTOR repressor, has been found to be the most significantly upregulated gene in neutrophils during disease attacks. Upon adrenergic stress, REDD1-induced autophagy triggers a pyrin-driven IL-1β maturation, and the release of IL-1β-bearing NETs. Consequently, not only the mode of action of IL-1β-targeting therapies is explained, but also new treatment prospects emerge with the evaluation of old or the design of new drugs targeting autophagy-induced NETosis. Information gained from FMF studies may subsequently be applied in more complex but still relevant inflammatory conditions, such as adult-onset Still's disease, gout, ulcerative colitis and Behçet's disease.

Phytochemicals as Novel Therapeutic Strategies for NLRP3 Inflammasome-Related Neurological, Metabolic, and Inflammatory Diseases

Several lines of evidence point out the relevance of nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome as a pivotal player in the pathophysiology of several neurological and psychiatric diseases (i.e., Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), amyotrophic lateral sclerosis, and major depressive disorder), metabolic disorders (i.e., obesity and type 2 diabetes) and chronic inflammatory diseases (i.e., intestinal inflammation, arthritis, and gout). Intensive research efforts are being made to achieve an integrated view about the pathophysiological role of NLRP3 inflammasome pathways in such disorders. Evidence is also emerging that the pharmacological modulation of NLRP3 inflammasome by phytochemicals could represent a promising molecular target for the therapeutic management of neurological, psychiatric, metabolic, and inflammatory diseases. The present review article has been intended to provide an integrated and critical overview of the available clinical and experimental evidence about the role of NLRP3 inflammasome in the pathophysiology of neurological, psychiatric, metabolic, and inflammatory diseases, including PD, AD, MS, depression, obesity, type 2 diabetes, arthritis, and intestinal inflammation. Special attention has been paid to highlight and critically discuss current scientific evidence on the effects of phytochemicals on NLRP3 inflammasome pathways and their potential in counteracting central neuroinflammation, metabolic alterations, and immune/inflammatory responses in such diseases.

Epigallocatechin-3-Gallate Prevents Acute Gout by Suppressing NLRP3 Inflammasome Activation and Mitochondrial DNA Synthesis

Gout is a chronic inflammatory disease evoked by the deposition of monosodium urate (MSU) crystals in joint tissues. The nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is responsible for the gout inflammatory symptoms induced by MSU crystals. We investigated whether epigallocatechin-3-gallate (EGCG) suppresses the activation of the NLRP3 inflammasome, thereby effectively preventing gouty inflammation. EGCG blocked MSU crystal-induced production of caspase-1(p10) and interleukin-1β in primary mouse macrophages, indicating its suppressive effect on the NLRP3 inflammasome. In an acute gout mouse model, oral administration of EGCG to mice effectively alleviated gout inflammatory symptoms in mouse foot tissue injected with MSU crystals. The in vivo suppressive effects of EGCG correlated well with the suppression of the NLRP3 inflammasome in mouse foot tissue. EGCG inhibited the de novo synthesis of mitochondrial DNA as well as the production of reactive oxygen species in primary mouse macrophages, contributing to the suppression of the NLRP3 inflammasome. These results show that EGCG suppresses the activation of the NLRP3 inflammasome in macrophages via the blockade of mitochondrial DNA synthesis, contributing to the prevention of gouty inflammation. The inhibitory effects of EGCG on the NLRP3 inflammasome make EGCG a promising therapeutic option for NLRP3-dependent diseases such as gout.

Tranilast directly targets NLRP3 to treat inflammasome-driven diseases

The dysregulation of NLRP3 inflammasome can cause uncontrolled inflammation and drive the development of a wide variety of human diseases, but the medications targeting NLRP3 inflammasome are not available in clinic. Here, we show that tranilast (TR), an old anti‐allergic clinical drug, is a direct NLRP3 inhibitor. TR inhibits NLRP3 inflammasome activation in macrophages, but has no effects on AIM2 or NLRC4 inflammasome activation. Mechanismly, TR directly binds to the NACHT domain of NLRP3 and suppresses the assembly of NLRP3 inflammasome by blocking NLRP3 oligomerization. In vivo experiments show that TR has remarkable preventive or therapeutic effects on the mouse models of NLRP3 inflammasome‐related human diseases, including gouty arthritis, cryopyrin‐associated autoinflammatory syndromes, and type 2 diabetes. Furthermore, TR is active ex vivo for synovial fluid mononuclear cells from patients with gout. Thus, our study identifies the old drug TR as a direct NLRP3 inhibitor and provides a potentially practical pharmacological approach for treating NLRP3‐driven diseases.

The Long Pentraxin 3 Contributes to Joint Inflammation in Gout by Facilitating the Phagocytosis of Monosodium Urate Crystals

The purpose of this study was to investigate the role of pentraxin 3 (PTX3), a pivotal component of the innate immune system, in gout. Levels of PTX3 and IL-1β in human samples were evaluated by ELISA. Development of murine gout was evaluated through the levels of cytokines (PTX3, CXCL1, and IL-1β) and neutrophil recruitment into the joint cavity. Phagocytosis of monosodium urate (MSU) crystals and caspase-1 activation were determined by flow cytometer. Acute gout patients showed elevated concentration of PTX3 in plasma and synovial fluid as compared with healthy and osteoarthritic subjects. Moreover, there was a positive correlation between intra-articular PTX3 and IL-1β levels. PTX3 was induced in the periarticular tissue of mice postinjection of MSU crystals. Importantly, Ptx3-deficient mice showed reduced inflammation in response to MSU crystal injection compared with wild-type mice, including reduction of neutrophil recruitment into the joint cavity and IL-1β and CXCL1 production. Interestingly, addition of PTX3 in vitro enhanced MSU crystal phagocytosis by monocytes and resulted in higher production of IL-1β by macrophages. This contribution of PTX3 to the phagocytosis of MSU crystals and consequent production of IL-1β occurred through a mechanism mainly dependent on FcγRIII. Thus, our results suggest that PTX3 acts as a humoral pattern recognition molecule in gout facilitating MSU crystal phagocytosis and contributing to the pathogenesis of gouty arthritis.

Anakinra for the treatment of acute gout flares: a randomized, double-blind, placebo-controlled, active-comparator, non-inferiority trial

OBJECTIVES

To evaluate the efficacy and safety of anakinra in treating acute gout flares in a randomized, double-blind, placebo-controlled, active comparator, non-inferiority (NI) trial.

METHODS

Patients with a crystal-proven acute gout flare were randomized (1: 1) to treatment with anakinra or treatment as usual (free choice: either colchicine, naproxen or prednisone). The primary end point was the change in pain between baseline and the averaged pain score on days 2-4 measured on a five-point rating scale. NI of anakinra would be established if the upper bound of the 95% CI of the numeric difference in changed pain scores between treatment groups did not exceed the NI limit of 0.4 in favour of treatment as usual, in the per-protocol (PP) and intention-to-treat (ITT) populations, assessed in an analysis of covariance model. Secondary outcomes included safety assessments, improvement in pain, swelling, tenderness and treatment response after 5 days, assessed using linear mixed models and binary logistic regression models.

RESULTS

Forty-three patients received anakinra and 45 treatment as usual. Anakinra was non-inferior (mean difference; 95% CI) to treatment as usual in both the PP (-0.13; -0.44, 0.18) and ITT (-0.18; -0.44, 0.08) populations. No unexpected or uncommon (serious) adverse events were observed in either treatment arm. Analyses of secondary outcomes showed that patients in both groups reported similar significant reductions in their gout symptoms.

CONCLUSION

Efficacy of anakinra was shown to be non-inferior to treatment as usual for the treatment of acute gout flares, suggesting that anakinra is an effective treatment alternative for acute gout flares.

TRIAL REGISTRATION

Het Nederlands Trial Register, www.trialregister.nl, NTR5234.

Anakinra Therapy for Non-cancer Inflammatory Diseases

Interleukin-1 (IL-1) is the prototypical inflammatory cytokine: two distinct ligands (IL-1α and IL-1β) bind the IL-1 type 1 receptor (IL-1R1) and induce a myriad of secondary inflammatory mediators, including prostaglandins, cytokines, and chemokines. IL-1α is constitutively present in endothelial and epithelial cells, whereas IL-1β is inducible in myeloid cells and released following cleavage by caspase-1. Over the past 30 years, IL-1-mediated inflammation has been established in a broad spectrum of diseases, ranging from rare autoinflammatory diseases to common conditions such as gout and rheumatoid arthritis (RA), type 2 diabetes, atherosclerosis, and acute myocardial infarction. Blocking IL-1 entered the clinical arena with anakinra, the recombinant form of the naturally occurring IL-1 receptor antagonist (IL-1Ra); IL-1Ra prevents the binding of IL-1α as well as IL-1β to IL-1R1. Quenching IL-1-mediated inflammation prevents the detrimental consequences of tissue damage and organ dysfunction. Although anakinra is presently approved for the treatment of RA and cryopyrin-associated periodic syndromes, off-label use of anakinra far exceeds its approved indications. Dosing of 100 mg of anakinra subcutaneously provides clinically evident benefits within days and for some diseases, anakinra has been used daily for over 12 years. Compared to other biologics, anakinra has an unparalleled record of safety: opportunistic infections, particularly Mycobacterium tuberculosis, are rare even in populations at risk for reactivation of latent infections. Because of this excellent safety profile and relative short duration of action, anakinra can also be used as a diagnostic tool for undefined diseases mediated by IL-1. Although anakinra is presently in clinical trials to treat cancer, this review focuses on anakinra treatment of acute as well as chronic inflammatory diseases.

The inflammasome as a target for pain therapy

The interleukin-1 family of cytokines are potent inducers of inflammation and pain. Proteolytic activation of this family of cytokines is under the control of several innate immune receptors that coordinate to form large multiprotein signalling platforms, termed inflammasomes. Recent evidence suggests that a wide range of inflammatory diseases, cancers, and metabolic and autoimmune disorders, in which pain is a common complaint, may be coordinated by inflammasomes. Activation of inflammasomes results in cleavage of caspase-1, which subsequently induces downstream initiation of several potent pro-inflammatory cascades. Therefore, it has been proposed that targeting inflammasome activity may be a novel and effective therapeutic strategy for these pain-related diseases. The purpose of this narrative review article is to provide the reader with an overview of the activation and regulation of inflammasomes and to investigate the potential therapeutic role of inflammasome inhibition in the treatment of diseases characterized by pain, including the following: complex regional pain syndrome, gout, rheumatoid arthritis, inflammatory pain, neuropathic pain, chronic prostatitis, chronic pelvic pain syndrome, and fibromyalgia. We conclude that the role of the inflammasome in pain-associated diseases is likely to be inflammasome subtype and disease specific. The currently available evidence suggests that disease-specific targeting of the assembly and activity of the inflammasome complex may be a novel therapeutic opportunity for the treatment of refractory pain in many settings.

Tranilast directly targets NLRP3 to treat inflammasome-driven diseases

The dysregulation of NLRP3 inflammasome can cause uncontrolled inflammation and drive the development of a wide variety of human diseases, but the medications targeting NLRP3 inflammasome are not available in clinic. Here, we show that tranilast (TR), an old anti-allergic clinical drug, is a direct NLRP3 inhibitor. TR inhibits NLRP3 inflammasome activation in macrophages, but has no effects on AIM2 or NLRC4 inflammasome activation. Mechanismly, TR directly binds to the NACHT domain of NLRP3 and suppresses the assembly of NLRP3 inflammasome by blocking NLRP3 oligomerization. In vivo experiments show that TR has remarkable preventive or therapeutic effects on the mouse models of NLRP3 inflammasome-related human diseases, including gouty arthritis, cryopyrin-associated autoinflammatory syndromes, and type 2 diabetes. Furthermore, TR is active ex vivo for synovial fluid mononuclear cells from patients with gout. Thus, our study identifies the old drug TR as a direct NLRP3 inhibitor and provides a potentially practical pharmacological approach for treating NLRP3-driven diseases.

Treatment of Inflammatory Diseases with IL-1 Blockade

Background

Autoinflammatory diseases are distinct from autoimmune diseases. Whereas autoinflammatory diseases are due to dysfunctional T-cells and B-cells, autoinflammatory diseases are due to overproduction of macrophage cytokines particularly interleukin-1 beta (IL-1β). A causative role for IL-1 in autoinflammatory diseases is derived from clinical studies blocking the IL-1 receptor or neutralizing monoclonal antibodies or soluble receptors.

Methods

A review was performed of clinical trials in autoinflammatory diseases using the IL-1 receptor antagonist (anakinra), the soluble IL-1 receptor (rilonacept), antibodies to IL-1β (canakinumab, gevokizumab) and anti-IL-1α (xilonix).

Findings

Anakinra blocks the IL-1 Receptor type 1 (IL-1R1) and therefore blocks the activities of both IL-1α and IL-1β. Off-label use of anakinra is common for a broad spectrum of inflammatory diseases. Neutralization of IL-1β is used to treat hereditary autoinflammatory diseases but also atherosclerosis. Rilonacept reduces arterial wall inflammation in patients with chronic kidney disease. Neutralization of IL-1α has prolonged life in patients with advanced metastatic colorectal cancer. Compared to other cytokine blocking therapies, reducing the activities of IL-1 has an excellent safety record.

Conclusions

Blocking IL-1 therapies can be used to treat a wide-spectrum of acute and chronic inflammatory diseases.

Identification of a selective and direct NLRP3 inhibitor to treat inflammatory disorders

Jiang et al. identify a selective and direct small-molecule inhibitor for NLRP3 and provide solid evidence showing that NLRP3 can be targeted in vivo to combat inflammasome-driven diseases.

The NLRP3 inflammasome has been implicated in the pathogenesis of a wide variety of human diseases. A few compounds have been developed to inhibit NLRP3 inflammasome activation, but compounds directly and specifically targeting NLRP3 are still not available, so it is unclear whether NLRP3 itself can be targeted to prevent or treat diseases. Here we show that the compound CY-09 specifically blocks NLRP3 inflammasome activation. CY-09 directly binds to the ATP-binding motif of NLRP3 NACHT domain and inhibits NLRP3 ATPase activity, resulting in the suppression of NLRP3 inflammasome assembly and activation. Importantly, treatment with CY-09 shows remarkable therapeutic effects on mouse models of cryopyrin-associated autoinflammatory syndrome (CAPS) and type 2 diabetes. Furthermore, CY-09 is active ex vivo for monocytes from healthy individuals or synovial fluid cells from patients with gout. Thus, our results provide a selective and direct small-molecule inhibitor for NLRP3 and indicate that NLRP3 can be targeted in vivo to combat NLRP3-driven diseases.

Anti-inflammatory panacea? The expanding therapeutics of interleukin-1 blockade

PURPOSE OF REVIEW

Blockade of interleukin (IL)-1 signaling is one of the oldest biologic therapies, yet the use of these agents is on the rise as the role of IL-1 activation is being recognized in a wide spectrum of inflammatory disorders. This review will cover established and emerging uses of IL-1 antagonism in rheumatic diseases.

RECENT FINDINGS

Expanding off-label indications for IL-1 blockade include neutrophil-dominant skin diseases, including pyoderma gangrenosum, hidradenitis supperativa, and pustular psoriasis. There is also increasing evidence for the use of IL-1 blockade in heart failure associated with rheumatic diseases. Somatic mosaicism in NLRP3 may explain the onset of later-in-life presentations of periodic fevers which are responsive to IL-1 blockade. Of importance, clinical response to anti-IL-1 therapy does not always denote protection from autoinflammatory disease complications such as macrophage activation syndrome or amyloidosis.

SUMMARY

Indications for IL-1 blocking therapies will likely continue to broaden, but given the rarity of many rheumatic diseases which respond to such treatment, rigorous, large clinical trials for each indication are unlikely to occur. Thus, recommended use of these medications will often fall to the discretion of the astute physician. However, medication cost and hurdles of insurance approval, rather than drug efficacy, may be the primary limitation for more widespread use.

Gout: will the "King of Diseases" be the first rheumatic disease to be cured?

Gout is the most common inflammatory arthritis in adults in the Western world. Characterized by hyperuricemia and the effects of acute and chronic inflammation in joints and bursa, gout leads to an agonizing, chronically painful arthritis. Arthritis can also be accompanied by urate nephropathy and subcutaneous urate deposits (tophi). Exciting new developments in the last decade have brought back the focus on this interesting, crystal-induced chronic inflammatory condition. New insights include the role of NALP3 inflammasome-induced inflammation in acute gout, the characterization of diagnostic signs on ultrasound and dual-energy computed tomography imaging modalities, the recognition of target serum urate less than 6 mg/day as the goal for urate-lowering therapies, and evidence-based treatment guidelines. A better understanding of disease mechanisms has enabled drug discovery - three new urate-lowering drugs have been approved in the last decade, with several more in the pipeline. We now recognize the important role that environment and genetics play in the causation of gout. A focus on the cardiac, renal, and metabolic comorbidities of gout will help translational research and discovery over the next decade.

Roles of the NLRP3 inflammasome in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, and persistent inflammation in circulatory and renal tissues is an important pathophysiological basis for DN. The essence of the microinflammatory state is the innate immune response, which is central to the occurrence and development of DN. Members of the inflammasome family, including both "receptors" and "regulators", are key to the inflammatory immune response. Nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) and other inflammasome components are able to detect endogenous danger signals, resulting in activation of caspase-1 as well as interleukin (IL)-1β, IL-18 and other cytokines; these events stimulate the inflammatory cascade reaction, which is crucial for DN. Hyperglycaemia, hyperlipidaemia and hyperuricaemia can activate the NLRP3 inflammasome, which then mediates the occurrence and development of DN through the K⁺ channel model, the lysosomal damage model and the active oxygen cluster model. In this review, we survey the involvement of the NLRP3 inflammasome in various signalling pathways and highlight different aspects of their influence on DN. We also explore the important effects of the NLRP3 inflammasome on kidney function and structural changes that occur during DN development and progression. It is becoming more evident that NLRP3 inflammasome targeting has therapeutic potential for the treatment of DN.

Innate immune perturbations, accumulating DAMPs and inflammasome dysregulation: A ticking time bomb in ageing

Ageing has pronounced effects on the immune system, including on innate immune cells. Whilst most studies suggest that total numbers of different innate immune cell populations do not change dramatically during ageing, many of their functions such as phagocytosis, antigen presentation and inflammatory molecule secretion decline. In contrast, many endogenous damage-associated molecular patterns (DAMPs) accumulate during ageing. These include reactive oxygen species (ROS) released from damaged mitochondria, extracellular nucleotides like ATP, high mobility group box (HMGB) 1 protein, oxidized low density lipoprotein, amyloid-beta (Aβ), islet amyloid polypeptide and particulates like monosodium urate (MSU) crystals and cholesterol crystals. Some of these DAMPs trigger the activation of inflammasomes, cytosolic danger sensing signalling platforms that drive both the maturation of specific pro-inflammatory mediators such as IL-1β, as well as the initiation of pro-inflammatory pyroptotic cell death. Herein, we review the evidence that dysregulated inflammasome activation, via altered innate immune cell functions and elevated levels of DAMPs, contributes to the establishment of chronic, low-grade inflammation (characterized by elevated levels of IL-6 and C-reactive protein) and the development of age-related pathological processes.

Treating rheumatological diseases and co-morbidities with interleukin-1 blocking therapies

The inflammatory cytokines IL-1α and IL-1β orchestrate local and systemic inflammatory responses underlying a broad spectrum of diseases. Three agents for reducing IL-1 activities are currently available. Anakinra is a recombinant form of the naturally occurring IL-1 receptor antagonist. Anakinra binds to the IL-1 receptor and prevents the activity of IL-1α and IL-1β. The soluble decoy receptor rilonacept and the neutralizing mAb canakinumab block IL-1β. A mAb directed against the IL-1 receptor and a neutralizing anti-human IL-1α are in clinical trials. The availability of therapies specifically targeting IL-1 unveiled the pathological role of IL-1-mediated inflammation in a broadening list of diseases. Conditions effectively treated with agents blocking IL-1 range from classic rheumatic diseases, such as RA and gout, to autoinflammatory syndromes, such as systemic JIA and FMF. However, IL-1 antagonism is also effective against highly prevalent inflammatory diseases, namely cardiovascular diseases and type 2 diabetes, conditions that are frequently encountered as co-morbidities in patients with rheumatic diseases. Thereby, IL-1 inhibition has the potential to lift the burden of disease for patients with rheumatic conditions, but also to provide clinical benefits beyond the efficacy on osteoarticular manifestations.

The NLRP3 inflammasome and stroke

Inflammasome pattern recognition receptors, which belong to the family of multi-meric proteins, play an important role in innate immunity, including NLRPs, NLRC, and NAIP. Among these receptors, NLRP3 (nucleotide-binding domain (NOD)-like receptor protein 3) inflammasome may activate the inflammation and participate in atherosclerosis, pathophysiology of myocardial infarction, resultin ischemia/reperfusion injury and stroke and other cardiovascular diseases. Effective regulation of NLRP3 may help prevent or even treat stroke. In recent years, the role of inflammation in stroke has attracted much attention, and the in-depth study of its mechanism of action is gradually clear. This mini-review focuses on the association of regulatory mechanisms of NLRP3 inflammasome with the development of stroke, which may supply some clues for future therapies and novel drug targets for stroke.

Interleukin-1 as a common denominator from autoinflammatory to autoimmune disorders: premises, perils, and perspectives

A complex web of dynamic relationships between innate and adaptive immunity is now evident for many autoinflammatory and autoimmune disorders, the first deriving from abnormal activation of innate immune system without any conventional danger triggers and the latter from self-/non-self-discrimination loss of tolerance, and systemic inflammation. Due to clinical and pathophysiologic similarities giving a crucial role to the multifunctional cytokine interleukin-1, the concept of autoinflammation has been expanded to include nonhereditary collagen-like diseases, idiopathic inflammatory diseases, and metabolic diseases. As more patients are reported to have clinical features of autoinflammation and autoimmunity, the boundary between these two pathologic ends is becoming blurred. An overview of monogenic autoinflammatory disorders, PFAPA syndrome, rheumatoid arthritis, type 2 diabetes mellitus, uveitis, pericarditis, Behçet's disease, gout, Sjögren's syndrome, interstitial lung diseases, and Still's disease is presented to highlight the fundamental points that interleukin-1 displays in the cryptic interplay between innate and adaptive immune systems.

An expanding role for interleukin-1 blockade from gout to cancer

There is an expanding role for interleukin (IL)-1 in diseases from gout to cancer. More than any other cytokine family, the IL-1 family is closely linked to innate inflammatory and immune responses. This linkage is because the cytoplasmic segment of all members of the IL-1 family of receptors contains a domain, which is highly homologous to the cytoplasmic domains of all toll-like receptors (TLRs). This domain, termed "toll IL-1 receptor (TIR) domain," signals as does the IL-1 receptors; therefore, inflammation due to the TLR and the IL-1 families is nearly the same. Fundamental responses such as the induction of cyclo-oxygenase type 2, increased surface expression of cellular adhesion molecules and increased gene expression of a broad number of inflammatory molecules characterizes IL-1 signal transduction as it does for TLR agonists. IL-1β is the most studied member of the IL-1 family because of its role in mediating autoinflammatory disease. However, a role for IL-1α in disease is being validated because of the availability of a neutralizing monoclonal antibody to human IL-1α. There are presently three approved therapies for blocking IL-1 activity. Anakinra is a recombinant form of the naturally occurring IL-1 receptor antagonist, which binds to the IL-1 receptor and prevents the binding of IL-1β as well as IL-1α. Rilonacept is a soluble decoy receptor that neutralizes primarily IL-1β but also IL-1α. Canakinumab is a human monoclonal antibody that neutralizes only IL-1β. Thus, a causal or significant contributing role can be established for IL-1β and IL-1α in human disease.

Interventions for tophi in gout

BACKGROUND

Tophi develop in untreated or uncontrolled gout. Their presence can lead to severe and potentially fatal complications. To date there have been no systematic reviews focused on the management of tophi in gout.

OBJECTIVES

To assess the benefits and harms of non-surgical and surgical treatments for the management of tophi in gout.

SEARCH METHODS

We searched three databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE. We handsearched American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts from 2010 to 2011, references from included studies and trial registries. We completed the most recent search on 20 May 2013.

SELECTION CRITERIA

All published randomised controlled trials (RCTs) or controlled clinical trials with quasi-randomised methods of allocating participants to treatment examining interventions for tophi in gout in adults. Possible interventions included urate-lowering pharmacological treatment (e.g. benzbromarone, probenecid, allopurinol, febuxostat, pegloticase), surgical removal or other interventions such as haemodialysis.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data from titles, abstracts and selected studies for detailed review, and extracted data and risk of bias independently. Major outcomes were number of participants with complete resolution of tophi, number of study participant withdrawals due to adverse events, joint pain reduction, function, quality of life, serum urate normalisation and total adverse events.

MAIN RESULTS

Only one study, at low risk of all biases, met the inclusion criteria. This was the pooled results from two RCTs (225 participants, 145 with tophi at baseline) randomised to one of three arms; pegloticase infusion every two weeks (biweekly), monthly pegloticase infusion (pegloticase infusion alternating with placebo infusion every two weeks) and placebo. Moderate-quality evidence from one study indicated that biweekly pegloticase 8 mg infusion reduced tophi in the subset of participants with tophi, but increased withdrawals due to adverse events in all participants, and monthly infusion appeared to result in less benefit.Biweekly pegloticase treatment resulted in resolution of tophi in 21/52 participants compared with 2/27 who received placebo (risk ratio (RR) 5.45, 95% confidence intervals (CI) 1.38 to 21.54; number needed to treat for an additional beneficial outcome (NNTB) 3 (95% CI 2 to 6).Eleven of 52 participants with monthly pegloticase treatment had complete resolution of one or more tophi compared with 2/27 who received placebo (RR 2.86, 95% CI 0.68 to 11.97).Participant-reported pain relief of 30% or greater, function, quality of life, serum urate normalisation, were reported for all participants but not separately for those with tophi; therefore, we did not include the results.Pegloticase administered biweekly resulted in more withdrawals due to adverse events compared with placebo (15/85 participants with pegloticase versus 1/43 participants with placebo; RR 7.59, 95% CI 1.04 to 55.55; number needed to treat for an additional harmful outcome (NNTH) 7, 95% CI 4 to 17). Pegloticase administered monthly also resulted in more withdrawals due to adverse events than placebo (16/84 participants with pegloticase versus 1/43 participants with placebo; RR 8.19, 95% CI 1.12 to 59.71; NNTH 6, 95% CI 4 to 14). Most withdrawals were due to infusion reactions.Total adverse events were high in all treatment groups: 80/85 participants administered pegloticase biweekly reported an adverse event compared with 41/43 from the placebo group (RR 0.99, 95% CI 0.91 to 1.07); 84/84 participants administered pegloticase monthly reported an adverse event versus 41/43 in the placebo group (RR 1.05, 95% CI 0.98 to 1.14). As 80% of adverse events were due to flares of gout, probably unrelated to the drug treatment per se, this may explain the high rate of adverse events in the placebo group - who were essentially untreated.

AUTHORS' CONCLUSIONS

This study showed pegloticase is probably beneficial in the management of tophi in gout, in terms of resolution of tophi, but with a high risk of adverse infusion reactions. However, there is a need for more RCT data considering other interventions, including surgical removal of tophi.

Fasinumab (REGN475), an antinerve growth factor monoclonal antibody, for the treatment of acute sciatic pain: results of a proof-of-concept study

OBJECTIVE

To evaluate the efficacy and safety of subcutaneously administered fasinumab (REGN475), a nerve growth factor-neutralizing antibody, in patients with acute sciatic pain receiving standard of care therapy.

METHODS

This was a double-blind, parallel-group, proof-of-concept study. Patients with unilateral, moderate-to-severe sciatic pain of 2-16 weeks' duration were randomized to a subcutaneous dose of placebo (n=51), fasinumab 0.1 mg/kg (n=53), or 0.3 mg/kg (n=53); follow-up was 12 weeks. Pain was assessed in a daily diary using a numerical rating scale (NRS) (0= no pain, 10= worst pain) for average and worst leg and back pain. The primary efficacy end point was the area under the curve of NRS scores for average leg pain from baseline to week 4. Key secondary end points included changes in average and worst leg and back pain from baseline to the end of week 4 and to each weekly study visit. Patient functioning (Oswestry Disability Index) and concomitant analgesic use were also assessed. Safety and tolerability were evaluated by treatment-emergent adverse events (TEAEs).

RESULTS

Demographic and clinical characteristics were similar among the treatment groups; 141 (88.7%) patients completed the study. For the primary end point, mean ± standard deviation area under the curve values from baseline to week 4 were not significantly different between placebo (96.8±6.0) and fasinumab 0.1 mg/kg (112.7±58.3; P=0.0610) or fasinumab 0.3 mg/kg (112.4±55.8; P=0.0923). All secondary efficacy end points of changes in pain and function demonstrated responses that were similar between placebo and fasinumab groups. Incidence of TEAEs was 45.1%, 50.9%, and 64.8% in the placebo, fasinumab 0.1mg/kg, and fasinumab 0.3 mg/kg groups, respectively. The most commonly reported TEAEs included paresthesia, arthralgia, pain in extremity, and headache.

CONCLUSION

Administration of fasinumab provided no significant clinical benefit compared with placebo for the pain or functional limitations associated with acute sciatica. Fasinumab was generally well tolerated and incidence of TEAEs appeared to be dose related.

Rilonacept for Gout Flare Prevention in Patients Receiving Uric Acid-lowering Therapy: Results of RESURGE, a Phase III, International Safety Study

Objective.

To evaluate the safety and efficacy of once-weekly subcutaneous rilonacept 160 mg for prevention of gout flares in patients initiating or continuing urate-lowering therapy (ULT).

Methods.

This phase III study was conducted in the United States, South Africa, Europe, and Asia. Adults (n = 1315, 18–80 yrs) with gout, who were initiating or continuing ULT, were randomized to treatment with weekly subcutaneous injections of rilonacept 160 mg or placebo for 16 weeks followed by a 4-week safety followup. The primary endpoint was safety, assessed by adverse events (AE) and laboratory values. Efficacy was a secondary endpoint.

Results.

Demographic and clinical characteristics were similar between treatments; predominantly male (87.8%), mean age 52.7 ± 11.3 years. Patients with ≥ 1 AE were 66.6% with rilonacept versus 59.1% placebo, with slightly more AE-related withdrawals with rilonacept (4.7% vs 3.0%) because of the greater incidence of injection site reactions (15.2% rilonacept, 3.3% placebo). Serious AE were similar in both groups, as were serious infections (0.9% placebo, 0.5% rilonacept); no tuberculosis or opportunistic infections occurred. Most common AE were headache, arthralgia, injection site erythema, accidental overdose, and pain in extremity. Of the 6 deaths, only 1 in the placebo group was considered treatment-related. At Week 16, rilonacept resulted in 70.3% fewer gout flares per patient (p < 0.0001), fewer patients with ≥ 1 and ≥ 2 gout flares (p < 0.0001), and 64.9% fewer gout flare days (p < 0.0001) relative to placebo.

Conclusion.

Weekly subcutaneous administration of rilonacept 160 mg showed no new safety signals. The safety profile was consistent with previous studies. Rilonacept also significantly reduced the risk of gout flares. Clinicaltrials.gov identifier NCT00856206; EudraCT No. 2008-007784-16.

Effects of Modified Simiao Decoction on IL-1 β and TNF α Secretion in Monocytic THP-1 Cells with Monosodium Urate Crystals-Induced Inflammation

Simiao pill, a Chinese herbal formula containing four herbs, has been used in the treatment of gouty arthritis for many years. The aim of this study was to explore the effects of modified Simiao decoction (MSD) on IL-1β and TNFα secretion in monocytic THP-1 cells with monosodium urate (MSU) crystals-induced inflammation. The MSU crystals-induced inflammation model in THP-1 cells was successfully established by the stimulation of phorbol 12-myristate 13-acetate (PMA) and MSU crystals. Then, the MSD-derived serum or control serum extracted from rat was administered to different treatment groups. The morphology of MSU crystals and THP-1 cells was observed. IL-1β and TNFα protein expression in supernatant of THP-1 cells were determined by ELISA. Our data demonstrated that MSU crystals induced time-dependent increase of IL-1β and TNFα. Moreover, MSD significantly decreased IL-1β release in THP-1 cells with MSU crystals-induced inflammation. These results suggest that MSD is promising in the treatment of MSU crystals-induced inflammation in THP-1 cells. MSD may act as an anti-IL-1 agent in treating gout. The underlying mechanism may be related to NALP3 inflammasome which needs to be validated in future studies.

The emerging role of biotechnological drugs in the treatment of gout

One of the most important therapeutic advances obtained in the field of rheumatology is the availability of the so-called bio(techno)logical drugs, which have deeply changed treatment perspectives in diseases such as rheumatoid arthritis and ankylosing spondylitis. According to the steadily increasing attention on gout, due to well-established prognostic and epidemiology implications, in the last 5 years, the same change of perspective has been observed also for this disease. In fact, several bio(techno)logical agents have been investigated both for the management of the articular gout symptoms, targeting mainly interleukin-1β, as well as urate-lowering therapies such as recombinant uricases. Among the IL-1β inhibitors, the majority of studies involve drugs such as anakinra, canakinumab, and rilonacept, but other compounds are under development. Moreover, other potential targets have been suggested, as, for example, the TNF alpha and IL-6, even if data obtained are less robust than those of IL-1β inhibitors. Regarding urate-lowering therapies, the recombinant uricases pegloticase and rasburicase clearly showed their effectiveness in gout patients. Also in this case, new compounds are under development. The aim of this review is to focus on the various aspects of different bio(techno)logical drugs in gouty patients.

How is inflammation initiated? Individual influences of IL-1, IL-18 and HMGB1

Pro-inflammatory cytokines are crucial for fighting infection and establishing immunity. Recently, other proteins, such as danger-associated molecular patterns (DAMPs), have also been appreciated for their role in inflammation and immunity. Following the formation and activation of multiprotein complexes, termed inflammasomes, two cytokines, IL-1β and IL-18, along with the DAMP High Mobility Group Box 1 (HMGB1), are released from cells. Although these proteins all lack classical secretion signals and are released by inflammasome activation, they each lead to different downstream consequences. This review examines how various inflammasomes promote the release of IL-1β, IL-18 and HMGB1 to combat pathogenic situations. Each of these effector molecules plays distinct roles during sterile inflammation, responding to viral, bacterial and parasite infection, and tailoring the innate immune response to specific threats.

Divergence of IL-1, IL-18, and cell death in NLRP3 inflammasomopathies

The inflammasome is a cytoplasmic multiprotein complex that promotes proinflammatory cytokine maturation in response to host- and pathogen-derived signals. Missense mutations in cryopyrin (NLRP3) result in a hyperactive inflammasome that drives overproduction of the proinflammatory cytokines IL-1β and IL-18, leading to the cryopyrin-associated periodic syndromes (CAPS) disease spectrum. Mouse lines harboring CAPS-associated mutations in Nlrp3 have elevated levels of IL-1β and IL-18 and closely mimic human disease. To examine the role of inflammasome-driven IL-18 in murine CAPS, we bred Nlrp3 mutations onto an Il18r-null background. Deletion of Il18r resulted in partial phenotypic rescue that abolished skin and visceral disease in young mice and normalized serum cytokines to a greater extent than breeding to Il1r-null mice. Significant systemic inflammation developed in aging Nlrp3 mutant Il18r-null mice, indicating that IL-1 and IL-18 drive pathology at different stages of the disease process. Ongoing inflammation in double-cytokine knockout CAPS mice implicated a role for caspase-1-mediated pyroptosis and confirmed that CAPS is inflammasome dependent. Our results have important implications for patients with CAPS and residual disease, emphasizing the need to explore other NLRP3-mediated pathways and the potential for inflammasome-targeted therapy.

Treating inflammation by blocking interleukin-1 in humans

IL-1 is a master cytokine of local and systemic inflammation. With the availability of specific IL-1 targeting therapies, a broadening list of diseases has revealed the pathologic role of IL-1-mediated inflammation. Although IL-1, either IL-1α or IL-1β, was administered to patients in order to improve bone marrow function or increase host immune responses to cancer, these patients experienced unacceptable toxicity with fever, anorexia, myalgias, arthralgias, fatigue, gastrointestinal upset and sleep disturbances; frank hypotension occurred. Thus it was not unexpected that specific pharmacological blockade of IL-1 activity in inflammatory diseases would be beneficial. Monotherapy blocking IL-1 activity in a broad spectrum of inflammatory syndromes results in a rapid and sustained reduction in disease severity. In common conditions such as heart failure and gout arthritis, IL-1 blockade can be effective therapy. Three IL-1blockers have been approved: the IL-1 receptor antagonist, anakinra, blocks the IL-1 receptor and therefore reduces the activity of IL-1α and IL-1β. A soluble decoy receptor, rilonacept, and a neutralizing monoclonal anti-interleukin-1β antibody, canakinumab, are also approved. A monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α are in clinical trials. By specifically blocking IL-1, we have learned a great deal about the role of this cytokine in inflammation but equally important, reducing IL-1 activity has lifted the burden of disease for many patients.

The Central Role of Anti-IL-1 Blockade in the Treatment of Monogenic and Multi-Factorial Autoinflammatory Diseases

Inherited autoinflammatory diseases are secondary to mutations of proteins playing a pivotal role in the regulation of the innate immunity leading to seemingly unprovoked episodes of inflammation. The understanding of the molecular pathways involved in these disorders has shed new lights on the pattern of activation and maintenance of the inflammatory response and disclosed new molecular therapeutic targets. Cryopyrin-associated periodic syndrome (CAPS) represents the prototype of an autoinflammatory disease. The study of the pathophysiological consequence of mutations in the cryopyrin gene (NLRP3) allowed the identification of intracellular pathways responsible for the activation and secretion of the potent inflammatory cytokine interleukin-1β (IL-1β). It became clear that several multi-factorial inflammatory conditions display a number of pathogenic and clinical similarities with inherited autoinflammatory diseases. The dramatic effect of interleukin-1 (IL-1) blockade in CAPS opened new perspectives for the treatment of other inherited and multi-factorial autoinflammatory disorders. Several IL-1 blockers are now available on the market. In this review we outline the more recent novelties in the treatment with different IL-1 blockers in inherited and multi-factorial autoinflammatory diseases.

Treatment of acute gouty arthritis in complex hospitalized patients with anakinra

OBJECTIVE

To report our experience with the efficacy and safety of anakinra for acute gouty arthritis in medically complex hospitalized patients.

METHODS

We reviewed the hospital charts of 26 patients treated with anakinra for crystal-induced arthritis since 2007. Demographics, comorbid conditions, reason for anakinra use, response to treatment, and any adverse outcomes were recorded.

RESULTS

Twenty-six patients received 40 courses of anakinra therapy. In 67% of patients, pain improved significantly within 24 hours, and complete resolution of signs and symptoms of gout occurred by day 5 in 72.5% of patients. Seven patients received multiple courses with no decrement in response with repeated treatments. Anakinra was well tolerated and no adverse outcomes were attributed to the medication. Only 1 patient appeared to be refractory to this form of interleukin-1 inhibition.

CONCLUSION

Anakinra is an effective and safe alternative treatment for acute gouty arthritis in medically complex hospitalized patients who fail or cannot undergo more conventional therapy.

NLRP3 and IL-1β in macrophages as critical regulators of metabolic diseases

The activation of the NLRP3 inflammasome leads to the autocleavage and activation of caspase-1. Caspase-1 cleaves several substrates, including the pro-inflammatory cytokine IL-1β. Inflammation, in particular IL-1β, has long been associated with the progression of metabolic disorders, and recent evidence suggests that the NLRP3 inflammasome plays a critical role in this inflammation. This review concentrates on the activation of NLRP3 during the development of metabolic disorders and the effect this activation has on the inflammatory state as well as the metabolic state of the cell.

Current concepts in the treatment of gouty arthritis

Gouty arthritis is an extremely painful condition that causes functional impairment. Gouty arthritis has become increasingly complex because of multiple comorbidities, iatrogenic factors and hyperuricemia that is refractory to treatment. In this review, we present a general overview of gouty arthritis including its pathophysiology, clinical presentations, diagnosis, predisposing factors and prophylactic therapy for preventing gouty arthritis flares.

How metabolism generates signals during innate immunity and inflammation

The interplay between immunity, inflammation, and metabolic changes is a growing field of research. Toll-like receptors and NOD-like receptors are families of innate immune receptors, and their role in the human immune response is well documented. Exciting new evidence is emerging with regard to their role in the regulation of metabolism and the activation of inflammatory pathways during the progression of metabolic disorders such as type 2 diabetes and atherosclerosis. The proinflammatory cytokine IL-1β appears to play a central role in these disorders. There is also evidence that metabolites such as NAD(+) (acting via deacetylases such as SIRT1 and SIRT2) and succinate (which regulates hypoxia-inducible factor 1α) are signals that regulate innate immunity. In addition, the extracellular overproduction of metabolites such as uric acid and cholesterol crystals acts as a signal sensed by NLRP3, leading to the production of IL-1β. These observations cast new light on the role of metabolism during host defense and inflammation.