What makes gouty inflammation so variable?

Acute gout arthritis flares contribute dominantly to gout-specific impaired health-related quality of life, representing a progressively increasing public health problem. Flares can be complex and expensive to treat, partly due to the frequent comorbidities. Unmet needs in gout management are more pressing given the markedly increasing gout flare hospital admission rates. In addition, chronic gouty arthritis can cause joint damage and functional impairment. This review addresses new knowledge on the basis for the marked, inherent variability of responses to deposited urate crystals, including the unpredictable and self-limited aspects of many gout flares. Specific topics reviewed include how innate immunity and two-signal inflammasome activation intersect with diet, metabolism, nutritional biosensing, the microbiome, and the phagocyte cytoskeleton and cell fate. The paper discusses the roles of endogenous constitutive regulators of inflammation, including certain nutritional biosensors, and emerging genetic and epigenetic factors. Recent advances in the basis of variability in responses to urate crystals in gout provide information about inflammatory arthritis, and have identified potential new targets and strategies for anti-inflammatory prevention and treatment of gouty arthritis

The inflammatory process of gout and its treatment.

Gouty arthritis is a characteristically intense acute inflammatory reaction that erupts in response to articular deposits of monosodium urate (MSU) crystals. Important recent molecular biologic advances in this field have given us a clear picture of the mechanistic basis of gouty inflammation. The innate immune inflammatory response is critically involved in the pathology of gout. Specifically, MSU crystals promote inflammation directly by stimulating cells via Toll-like receptor signaling and by providing a surface for cleavage of C5 and formation of complement membrane attack complex (C5b-9), culminating in secretion of cytokines, chemokines, and other inflammatory mediators with a dramatic influx of neutrophils into the joint. Despite the detailed mechanistic picture for gouty inflammation, there are no placebo-controlled, randomized clinical studies for any of the therapies commonly used, although comparative studies have demonstrated that many nonsteroidal anti-inflammatory drugs are equivalent to indomethacin with respect to controlling acute gouty attacks. In general, the first line of anti-inflammatory therapy for acute gout is nonsteroidal anti-inflammatory drugs, and the selective cyclo-oxygenase-2 inhibitor celecoxib can be used where appropriate. The second line of treatment is glucocorticosteroids, given systemically (oral, intravenous, or intramuscular) or intra-articularly. Alternatively, synthetic adrenocorticotropic hormone is effective, partly via induction of adrenal glucocorticosteroids and partly via rapid peripheral suppression of leukocyte activation by melatonin receptor 3 signaling. The third line of treatment is oral colchicine, which is highly effective when given early in an acute gouty attack, but it is poorly tolerated because of predictable gastrointestinal side effects

Patients Prescribed Anakinra for Acute Gout Have Baseline Increased Burden of Hyperuricemia, Tophi, and Comorbidities, and Ultimate All-Cause Mortality.

Objective:The interleukin-1 (IL-1) receptor antagonist anakinra is an effective, off-label option in acute gout flares, when conventional therapy options are narrowed. We performed a retrospective, randomized, case-controlled study to gain clinical insight on baseline factors for gout patients most likely to receive anakinra, and ultimate mortality of those who received anakinra. Methods:Of 1451 gout patients seen between January 2003 and January 2015 in a Veterans Affairs (VA) rheumatology group practice, under stringent managed care principles, 13 (100% male), who received anakinra at least once for flares, were compared with 1:4 age- and sex-matched gout controls. Each patient's first rheumatology encounter was studied by factor analysis for variables associated with later anakinra. Results:At baseline, patients that received anakinra had higher urate burden (palpable tophi [10/13] vs controls [16/52], P = .003), serum urate ([10.6 mg/dL] vs controls [7.6 mg/dL], P < .0001), and East Asian descent ([7/13] vs [16/52], P = .041). The anakinra group had higher ultimate all-cause mortality ([6/13] vs controls [7/52], relative risk [RR] = 3.43, 95% confidence interval [CI] = 1.39-8.48, P = .0076). Factor analysis showed baseline visit palpable tophus and statin use to be most strongly associated with later anakinra use. Increased mortality of anakinra users, as per a factorial analysis, was linked more strongly to comorbidities than to anakinra. Conclusions:At baseline rheumatology gout encounter, higher urate, palpable tophi, statin prescription, and East Asian descent were associated with later anakinra use for flares. Mortality was more closely associated to the presence of comorbidities at baseline rheumatology visit than to anakinra prescription

Systematic review and quality analysis of emerging diagnostic measures for calcium pyrophosphate crystal deposition disease.

ObjectivesCalcium pyrophosphate crystal deposition disease (CPPD) is common, yet prevalence and overall clinical impact remain unclear. Sensitivity and specificity of CPPD reference standards (conventional crystal analysis (CCA) and radiography (CR)) were meta-analysed by EULAR (published 2011). Since then, new diagnostic modalities are emerging. Hence, we updated 2009-2016 literature findings by systematic review and evidence grading, and assessed unmet needs.MethodsWe performed systematic search of full papers (PubMed, Scopus/EMBASE, Cochrane 2009-2016 databases). Search terms included CPPD, chondrocalcinosis, pseudogout, ultrasound, MRI, dual energy CT (DECT). Paper selection, data abstraction, EULAR evidence level, and Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 bias and applicability grading were performed independently by 3 authors.ResultsWe included 26 of 111 eligible papers, which showed emergence in CPPD diagnosis of ultrasound (U/S), and to lesser degree, DECT and Raman spectroscopy. U/S detected CPPD crystals in peripheral joints with sensitivity >80%, superior to CR. However, most study designs, though analytical, yielded low EULAR evidence level. DECT was marginally explored for CPPD, compared with 35 published DECT studies in gout. QUADAS-2 grading indicated strong applicability of U/S, DECT and Raman spectroscopy, but high study bias risk (in ∼30% of papers) due to non-controlled designs, and non-randomised subject selection.ConclusionsThough CCA and CR remain reference standards for CPPD diagnosis, U/S, DECT and Raman spectroscopy are emerging U/S sensitivity appears to be superior to CR. We identified major unmet needs, including for randomised, blinded, controlled studies of CPPD diagnostic performance and rigorous analyses of 4 T MRI and other emerging modalities

Gout. Novel therapies for treatment of gout and hyperuricemia

In the past few decades, gout has increased not only in prevalence, but also in clinical complexity, the latter accentuated in part by a dearth of novel advances in treatments for hyperuricemia and gouty arthritis. Fortunately, recent research reviewed here, much of it founded on elegant translational studies of the past decade, highlights how gout can be better managed with cost-effective, well-established therapies. In addition, the advent of both new urate-lowering and anti-inflammatory drugs, also reviewed here, promises for improved management of refractory gout, including in subjects with co-morbidities such as chronic kidney disease. Effectively delivering improved management of hyperuricemia and gout will require a frame shift in practice patterns, including increased recognition of the implications of refractory disease and frequent noncompliance of patients with gout, and understanding the evidence basis for therapeutic targets in serum urate-lowering and gouty inflammation

Npp1 promotes atherosclerosis in ApoE knockout mice.

Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) generates inorganic pyrophosphate (PP(i)), a physiologic inhibitor of hydroxyapatite deposition. In a previous study, we found NPP1 expression to be inversely correlated with the degree of atherosclerotic plaque calcification. Moreover, function-impairing mutations of ENPP1, the gene encoding for NPP1, are associated with severe, artery tunica media calcification and myointimal hyperplasia with infantile onset in human beings. NPP1 and PP(i) have the potential to modulate atherogenesis by regulating arterial smooth muscle cell (SMC) differentiation and function, including increase of pro-atherogenic osteopontin (OPN) expression. Hence, this study tested the hypothesis that NPP1 deficiency modulates both atherogenesis and atherosclerotic intimal plaque calcification. Npp1/ApoE double deficient mice were generated by crossing mice bearing the ttw allele of Enpp1 (that encodes a truncation mutation) with ApoE null mice and fed with high-fat/high-cholesterol atherogenic diet. Atherosclerotic lesion area and calcification were examined at 13, 18, 23 and 28 weeks of age. The aortic SMCs isolated from both ttw/ttw ApoE(-/-) and ttw/+ ApoE(-/-) mice demonstrated decreased Opn expression. The 28-week-old ttw/ttw ApoE(-/-) and ttw/+ ApoE(-/-) had significantly smaller atherosclerotic lesions compared with wild-type congenic ApoE(-/-) mice. Only ttw/ttw but not ttw/+ mice developed artery media calcification. Furthermore in ttw/+ mice, there was a tendency towards increased plaque calcification compared to ApoE(-/-) mice without Npp1 deficiency. We conclude that Npp1 promotes atherosclerosis, potentially mediated by Opn expression in ApoE knockout mice

Adherence to guidelines and the Screening Tool of Older Persons' potentially inappropriate Prescriptions criteria for colchicine dosing for gout treatment in beneficiaries of the Nova Scotia Seniors' Pharmacare Program Clinical Therapeutics

Purpose: Colchicine is commonly used in the management of gout; however, older persons have higher risks of toxicity. Accordingly, the Screening Tool of Older Person’s potentially inappropriate Prescriptions (STOPP) criteria for colchicine consider 43 months of treatment as potentially inappropriate in older persons. Recent evidence also suggests lower dosing of colchicine is as effective and results in fewer toxicities than high-dose colchicine. The objectives of this study were to determine the dose, duration, and prescribers of colchicine and to evaluate adherence to the STOPP criteria and international guidelines for colchicine in older persons. Methods: A retrospective, observational study was conducted from April 1, 2006 to March 31, 2011 to evaluate colchicine use. Nova Scotia Seniors’ Pharmacare Program beneficiaries who met inclusion criteria for an incident case of gout and who filled at least 1prescription for colchicine during the study period were included. Colchicine dose and duration were reported descriptively. Multivariate logistic regression was used to identify predictors of the study population in making a claim for colchicine 490 and 4180 days. Findings: A total of 518 persons were dispensed 1327 courses of colchicine during the study period. The mean daily dose of colchicine ranged from 1.39 to 1.50 mg. Colchicine doses 41.2 mg were prescribed in approximately one-third of the study population. Colchicine was prescribed for 490 days in 14.2% of treatment courses and for 4180 days in 8.1% of treatment courses. Female sex was the only predictor of treatment duration 490 days. Implications: This study is the first to report on colchicine dose and duration using STOPP criteria in a specific cohort of older persons with incident gout. Strategies to improve colchicine prescribing in older persons are needed