SciCombinator

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Concept: Rheumatoid arthritis

303

Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the “inflammatory reflex,” is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases.

Concepts: Inflammation, Cytokine, Interleukin 1, Rheumatoid arthritis, Vagus nerve, Autoimmune disease, Vagus nerve stimulation, Tumor necrosis factor-alpha

242

Folklore remedies for pain and inflammation in rheumatoid arthritis include the application of magnets and copper to the skin. Despite the popular use of devices containing magnets or copper for this purpose, little research has been conducted to evaluate the efficacy of such treatments.

Concepts: Inflammation, Clinical trial, Rheumatoid arthritis, Rheumatology, Pain, Non-steroidal anti-inflammatory drug, Anti-inflammatory, Acupuncture

199

A high circulating concentration of interleukin 6 is associated with increased risk of coronary heart disease. Blockade of the interleukin-6 receptor (IL6R) with a monoclonal antibody (tocilizumab) licensed for treatment of rheumatoid arthritis reduces systemic and articular inflammation. However, whether IL6R blockade also reduces risk of coronary heart disease is unknown.

Concepts: Immune system, Rheumatoid arthritis, Osteoclast, Interleukin, Interleukin 6, Tocilizumab, Interleukin-6 receptor, Ciliary neurotrophic factor

198

Signals controlling the generation of regulatory B (Breg) cells remain ill-defined. Here we report an “auto”-regulatory feedback mechanism between plasmacytoid dendritic cells (pDCs) and Breg cells. In healthy individuals, pDCs drive the differentiation of CD19(+)CD24(hi)CD38(hi) (immature) B cells into IL-10-producing CD24(+)CD38(hi) Breg cells and plasmablasts, via the release of IFN-α and CD40 engagement. CD24(+)CD38(hi) Breg cells conversely restrained IFN-α production by pDCs via IL-10 release. In systemic lupus erythematosus (SLE), this cross-talk was compromised; pDCs promoted plasmablast differentiation but failed to induce Breg cells. This defect was recapitulated in healthy B cells upon exposure to a high concentration of IFN-α. Defective pDC-mediated expansion of CD24(+)CD38(hi) Breg cell numbers in SLE was associated with altered STAT1 and STAT3 activation. Both altered pDC-CD24(+)CD38(hi) Breg cell interactions and STAT1-STAT3 activation were normalized in SLE patients responding to rituximab. We propose that alteration in pDC-CD24(+)CD38(hi) Breg cell interaction contributes to the pathogenesis of SLE.

Concepts: Cell nucleus, Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus

194

There is strong diurnal variation in the symptoms and severity of chronic inflammatory diseases, such as rheumatoid arthritis. In addition, disruption of the circadian clock is an aggravating factor associated with a range of human inflammatory diseases. To investigate mechanistic links between the biological clock and pathways underlying inflammatory arthritis, mice were administered collagen (or saline as a control) to induce arthritis. The treatment provoked an inflammatory response within the limbs, which showed robust daily variation in paw swelling and inflammatory cytokine expression. Inflammatory markers were significantly repressed during the dark phase. Further work demonstrated an active molecular clock within the inflamed limbs and highlighted the resident inflammatory cells, fibroblast-like synoviocytes (FLSs), as a potential source of the rhythmic inflammatory signal. Exposure of mice to constant light disrupted the clock in peripheral tissues, causing loss of the nighttime repression of local inflammation. Finally, the results show that the core clock proteins CRYPTOCHROMES 1 and 2 repressed inflammation within the FLSs, and provide novel evidence that a CRYPTOCHROME activator has anti-inflammatory properties in human cells. We conclude that under chronic inflammatory conditions, the clock actively represses inflammatory pathways during the dark phase. This interaction has exciting potential as a therapeutic avenue for treatment of inflammatory disease.-Hand, L. E., Hopwood, T. W., Dickson, S. H., Walker, A. L., Loudon, A. S. I., Ray D. W., Bechtold, D. A., Gibbs, J. E. The circadian clock regulates inflammatory arthritis.

Concepts: Inflammation, Interleukin 1, Asthma, Rheumatoid arthritis, Vasculitis, Anti-inflammatory, Circadian rhythm, C-reactive protein

179

BACKGROUND: Musculoskeletal conditions (MSCs) are widely prevalent in present-day society, with resultant high healthcare costs and substantial negative effects on patient health and quality of life. The main aim of this overview was to synthesize evidence from systematic reviews on the effects of exercise therapy (ET) on pain and physical function for patients with MSCs. In addition, the evidence for the effect of ET on disease pathogenesis, and whether particular components of exercise programs are associated with the size of the treatment effects, was also explored. METHODS: We included four common conditions: fibromyalgia (FM), low back pain (LBP), neck pain (NP), and shoulder pain (SP), and four specific musculoskeletal diseases: osteoarthritis (OA), rheumatoid arthritis (RA), ankylosing spondylitis (AS), and osteoporosis (OP). We first included Cochrane reviews with the most recent update being January 2007 or later, and then searched for non-Cochrane reviews published after this date. Pain and physical functioning were selected as primary outcomes. RESULTS: We identified 9 reviews, comprising a total of 224 trials and 24,059 patients. In addition, one review addressing the effect of exercise on pathogenesis was included. Overall, we found solid evidence supporting ET in the management of MSCs, but there were substantial differences in the level of research evidence between the included diagnostic groups. The standardized mean differences for knee OA, LBP, FM, and SP varied between 0.30 and 0.65 and were significantly in favor of exercise for both pain and function. For NP, hip OA, RA, and AS, the effect estimates were generally smaller and not always significant. There was little or no evidence that ET can influence disease pathogenesis. The only exception was for osteoporosis, where there was evidence that ET increases bone mineral density in postmenopausal women, but no significant effects were found for clinically relevant outcomes (fractures). For LBP and knee OA, there was evidence suggesting that the treatment effect increases with the number of exercise sessions. CONCLUSIONS: There is empirical evidence that ET has beneficial clinical effects for most MSCs. Except for osteoporosis, there seems to be a gap in the understanding of the ways in which ET influences disease mechanisms.

Concepts: Osteoporosis, Back pain, Rheumatoid arthritis, Osteoarthritis, Acupuncture, Arthritis, Ankylosing spondylitis, Musculoskeletal disorders

172

The aim is to characterize subgroups or phenotypes of rheumatoid arthritis (RA) patients using a systems biology approach. The discovery of subtypes of rheumatoid arthritis patients is an essential research area for the improvement of response to therapy and the development of personalized medicine strategies.

Concepts: Medicine, Evolution, Rheumatoid arthritis, Rheumatology, Systems biology

171

Anti-drug antibodies (ADAs) against biologic agents may be clinically significant and potentially alter a biologic drug’s treatment efficacy. This systematic review aims to 1) determine the prevalence of ADAs against infliximab, etanercept, adalimumab, and ustekinumab in psoriasis patients; 2) ascertain whether ADAs are associated with changes in drug efficacy; and 3) explore the use of concomitant methotrexate to prevent ADA formation. Through a systematic search using MEDLINE and EMBASE from January 29, 1950 to March 29, 2013, we identified 25 studies that met the inclusion criteria. Of 7,969 psoriasis patients, 950 patients tested positive for ADAs. Antibodies against infliximab, etanercept, adalimumab, and ustekinumab were reported in 5.4%-43.6%, 0.0%-18.3%, 6.6%-44.8%, and 3.8%-5.5% of patients, respectively. Anti-infliximab antibodies were associated with lower serum infliximab concentrations in three studies and decreased treatment response in five studies. ADAs against etanercept were non-neutralizing and not associated with any apparent effects on clinical response. Anti-adalimumab antibodies were associated with lower serum adalimumab concentrations in three of five studies and reduced clinical efficacy in four studies. Two of six studies reported that anti-ustekinumab antibodies were associated with lower PASI responses, and three ustekinumab studies noted that most of these antibodies were neutralizing. Although the use of concomitant methotrexate with biologic agents to prevent ADA formation in other immune-mediated diseases is promising, their use in psoriasis is sparse. ADA development remains a challenge with biologic therapies and therefore should be considered in psoriasis patients who experience diminished treatment response. This article is protected by copyright. All rights reserved.

Concepts: Monoclonal antibodies, Rheumatoid arthritis, Infliximab, Ankylosing spondylitis, Psoriatic arthritis, Psoriasis, Etanercept, Adalimumab

171

Accompanying the increased use of biologic and non-biologic antirheumatic agents, patients with RA have been exposed to an increased risk of Pneumocystis jirovecii infection, which causes acute fulminant P. jirovecii pneumonia (PCP). Mortality in this population is higher than in HIV-infected individuals. Several guidelines and recommendations for HIV-infected individuals are available; however, such guidelines for RA patients remain less clear. Between 2006 and 2008 we encountered a clustering event of P. jirovecii infection among RA outpatients. Through our experience with this outbreak and a review of the recent medical literature regarding asymptomatic colonization and its clinical significance, transmission modes of infection and prophylaxis of PCP, we have learned the following lessons: PCP outbreaks among RA patients can occur through person-to-person transmission in outpatient facilities; asymptomatic carriers serve as reservoirs and sources of infection; and short-term prophylaxis for eradication of P. jirovecii is effective in controlling PCP outbreaks among RA outpatients.

Concepts: Epidemiology, Rheumatoid arthritis, Rheumatology, Methotrexate, Cyclophosphamide, Disease-modifying antirheumatic drug, Hydroxychloroquine, Sulfasalazine

171

BACKGROUND: Uveitis is an autoimmune disease of the eye that refers to any of a number of intraocular inflammatory conditions. Because it is a rare disease, uveitis is often overlooked, and the possible associations between uveitis and extra-ocular disease manifestations are not well known. The aim of this study was to characterise uveitis in a large sample of patients and to evaluate the relationship between uveitis and systemic diseases. METHODS: The present study is a cross-sectional study of a cohort of patients with uveitis. Records from consecutive uveitis patients who were seen by the Uveitis Service in the Department of Ophthalmology at the Medical University of Vienna between 1995 and 2009 were selected from the clinical databases. The cases were classified according to the Standardization of Uveitis Nomenclature Study Group criteria for uveitis. RESULTS: Data were available for 2619 patients, of whom 59.9% suffered from anterior, 14.8% from intermediate, 18.3% from posterior and 7.0% from panuveitis. 37.2% of all cases showed an association between uveitis and extra-organ diseases; diseases with primarily arthritic manifestations were seen in 10.1% of all cases, non-infectious systemic diseases (i.e., Behcet’s disease, sarcoidosis or multiple sclerosis) in 8.4% and infectious uveitis in 18.7%. 49.4% of subjects suffering from anterior uveitis tested positively for the HLA-B27 antigen. In posterior uveitis cases 29% were caused by ocular toxoplasmosis and 17.7% by multifocal choroiditis. CONCLUSION: Ophthalmologists, rheumatologists, infectiologists, neurologists and general practitioners should be familiar with the differential diagnosis of uveitis. A better interdisciplinary approach could help in tailoring of the work-up, earlier diagnosis of co-existing diseases and management of uveitis patients.

Concepts: Medicine, Epidemiology, Medical terms, Infection, Rheumatoid arthritis, Ophthalmology, Ankylosing spondylitis, Uveitis