Mechanisms governing the normal resolution processes of inflammation are poorly understood, yet their elucidation may lead to a greater understanding of the pathogenesis of chronic inflammation. The removal of neutrophils and their potentially histotoxic contents is one prerequisite of resolution. Engulfment by macrophages is an important disposal route, and changes in the senescent neutrophil that are associated with their recognition by macrophages are the subject of this investigation. Over 24 h in culture an increasing proportion of human neutrophils from peripheral blood or acutely inflamed joints underwent morphological changes characteristic of programmed cell death or apoptosis. Time-related chromatin cleavage in an internucleosomal pattern indicative of the endogenous endonuclease activation associated with programmed cell death was also demonstrated. A close correlation was observed between the increasing properties of apoptosis in neutrophils and the degree of macrophage recognition of the aging neutrophil population, and a direct relationship between these parameters was confirmed within aged neutrophil populations separated by counterflow centrifugation into fractions with varying proportions of apoptosis. Macrophages from acutely inflamed joints preferentially ingested apoptotic neutrophils and histological evidence was presented for occurrence of the process in situ. Programmed cell death is a phenomenon of widespread biological importance and has not previously been described in a cell of the myeloid line. Because it leads to recognition of intact senescent neutrophils that have not necessarily disgorged their granule contents, these processes may represent a mechanism for the removal of neutrophils during inflammation that also serves to limit the degree of tissue injury.

The American Rheumatism Association sub-committe on classification criteria for gout analyzed data from more than 700 patients with gout, pseudogout, rheumatoid arthritis, or septic arthritis. Criteria for classifying a patient as having gout were a) the presence of characteristic urate crystals in the joint fluid, and/or b) a topus proved to contain urate crystals by chemical or polarized light microscopic means, and/or c) the presence of six of the twelve clinical, laboratory, and X-ray phenomena listed in Table 5.

Only a few autoantibodies that are more or less specific for RA have been described so far. The rheumatoid factor most often tested for is not very specific for RA, while the more specific antiperinuclear factor for several reasons is not routinely used as a serological parameter. Here we show that autoantibodies reactive with synthetic peptides containing the unusual amino acid citrulline, a posttranslationally modified arginine residue, are specifically present in the sera of RA patients. Using several citrulline-containing peptide variants in ELISA, antibodies could be detected in 76% of RA sera with a specificity of 96%. Sera showed a remarkable variety in the reactivity pattern towards different citrulline-containing peptides. Affinity-purified antibodies were shown to be positive in the immunofluorescence-based antiperinuclear factor test, and in the so-called antikeratin antibody test, and were reactive towards filaggrin extracted from human epidermis. The specific nature of these antibodies and the presence of these antibodies early in disease, even before other disease manifestations occur, are indicative for a possible role of citrulline-containing epitopes in the pathogenesis of RA.

This report shows that interleukin (IL) 17-producing T helper type 17 (Th17) cells predominantly express CC chemokine receptor (CCR) 6 in an animal model of rheumatoid arthritis (RA). Th17 cells induced in vivo in normal mice via homeostatic proliferation similarly express CCR6, whereas those inducible in vitro by transforming growth factor beta and IL-6 additionally need IL-1 and neutralization of interferon (IFN) gamma and IL-4 for CCR6 expression. Forced expression of RORgamma t, a key transcription factor for Th17 cell differentiation, induces not only IL-17 but also CCR6 in naive T cells. Furthermore, Th17 cells produce CCL20, the known ligand for CCR6. Synoviocytes from arthritic joints of mice and humans also produce a large amount of CCL20, with a significant correlation (P = 0.014) between the amounts of IL-17 and CCL20 in RA joints. The CCL20 production by synoviocytes is augmented in vitro by IL-1beta, IL-17, or tumor necrosis factor alpha, and is suppressed by IFN-gamma or IL-4. Administration of blocking anti-CCR6 monoclonal antibody substantially inhibits mouse arthritis. Thus, the joint cytokine milieu formed by T cells and synovial cells controls the production of CCL20 and, consequently, the recruitment of CCR6+ arthritogenic Th17 cells to the inflamed joints. These results indicate that CCR6 expression contributes to Th17 cell function in autoimmune disease, especially in autoimmune arthritis such as RA.

Immunoglobulins are the major secretory products of the adaptive immune system. Each is characterized by a distinctive set of glycoforms that reflects the wide variation in the number, type, and location of their oligosaccharides. In a given physiological state, glycoform populations are reproducible; therefore, disease-associated alterations provide diagnostic biomarkers (e.g., for rheumatoid arthritis) and contribute to disease pathogenesis. The oligosaccharides provide important recognition epitopes that engage with lectins, endowing the immunoglobulins with an expanded functional repertoire. The sugars play specific structural roles, maintaining and modulating effector functions that are physiologically relevant and can be manipulated to optimize the properties of therapeutic antibodies. New molecular models of all the immunoglobulins are included to provide a basis for informed and critical discussion. The models were constructed by combining glycan sequencing data with oligosaccharide linkage and dynamics information from the Glycobiology Institute experimental database and protein structural data from "The Protein Data Bank."

OBJECTIVE

To compare the incidence of cardiovascular (CV) events in persons with rheumatoid arthritis (RA) with that in people from the general population, adjusting for traditional CV risk factors.

METHODS

Two hundred thirty-six consecutive patients with RA were assessed for the 1-year occurrence of 1) CV-related hospitalizations, including myocardial infarction, stroke or other arterial occlusive events, or arterial revascularization procedures, or 2) CV deaths. Both outcomes were ascertained by medical records or death certificates. For comparison, we used CV events that occurred during an 8-year period among participants in an epidemiologic study of atherosclerosis and CV disease who were ages 25-65 years at study entry. We calculated the age- and sex-stratified incidence rate ratio (IRR) of CV events between the 2 cohorts and used Poisson regression to adjust for age, sex, smoking status, diabetes mellitus, hypercholesterolemia, systolic blood pressure, and body mass index.

RESULTS

Of the 236 RA patients, 234 were observed for 252 patient-years, during which 15 CV events occurred. Of these, 7 incident events occurred during the 204 patient-years contributed by patients ages 25-65 years, for an incidence of 3.43 per 100 patient-years. In the comparison cohort, 4,635 community-dwelling persons were followed up for 33,881 person-years, during which 200 new events occurred, for an incidence of 0.59 per 100 person-years. The age- and sex-adjusted IRR of incident CV events associated with RA was 3.96 (95% confidence interval [95% CI] 1.86-8.43). After adjusting for CV risk factors using Poisson regression, the IRR decreased slightly, to 3.17 (95% CI 1.33-6.36).

CONCLUSIONS

The increased incidence of CV events in RA patients is independent of traditional CV risk factors. This suggests that additional mechanisms are responsible for CV disease in RA. Physicians who provide care to individuals with RA should be aware of their increased risk of CV events and implement appropriate diagnostic and therapeutic measures.

OBJECTIVE

To develop a set of disease activity measures for use in rheumatoid arthritis (RA) clinical trials, as well as to recommend specific methods for assessing each outcome measure. This is not intended to be a restrictive list, but rather, a core set of measures that should be included in all trials.

METHODS

We evaluated disease activity measures commonly used in RA trials, to determine which measures best met each of 5 types of validity: construct, face, content, criterion, and discriminant. The evaluation consisted of an initial structured review of the literature on the validity of measures, with an analysis of data obtained from clinical trials to fill in gaps in this literature. A committee of experts in clinical trials, health services research, and biostatistics reviewed the validity data. A nominal group process method was used to reach consensus on a core set of disease activity measures. This set was then reviewed and finalized at an international conference on outcome measures for RA clinical trials. The committee also selected specific ways to assess each outcome.

RESULTS

The core set of disease activity measures consists of a tender joint count, swollen joint count, patient's assessment of pain, patient's and physician's global assessments of disease activity, patient's assessment of physical function, and laboratory evaluation of 1 acute-phase reactant. Together, these measures sample the broad range of improvement in RA (have content validity), and all are at least moderately sensitive to change (have discriminant validity). Many of them predict other important long-term outcomes in RA, including physical disability, radiographic damage, and death. Other disease activity measures frequently used in clinical trials were not chosen for any one of several reasons, including insensitivity to change or duplication of information provided by one of the core measures (e.g., tender joint score and tender joint count). The committee also proposes specific ways of measuring each outcome.

CONCLUSIONS

We propose a core set of outcome measures for RA clinical trials. We hope this will decrease the number of outcomes assessed and standardize outcomes assessments. Further, we hope that these measures will be found useful in long-term studies.

OBJECTIVE

To evaluate the efficacy, pharmacokinetics, immunogenicity, and safety of multiple infusions of a chimeric monoclonal anti-tumor necrosis factor alpha antibody (cA2) (infliximab; Remicade, Centocor, Malvern, PA) given alone or in combination with low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients.

METHODS

In a 26-week, double-blind, placebo-controlled, multicenter trial, 101 patients with active RA exhibiting an incomplete response or flare of disease activity while receiving low-dose MTX were randomized to 1 of 7 groups of 14-15 patients each. The patients received either intravenous cA2 at 1, 3, or 10 mg/kg, with or without MTX 7.5 mg/week, or intravenous placebo plus MTX 7.5 mg/week at weeks 0, 2, 6, 10, and 14 and were followed up through week 26.

RESULTS

Approximately 60% of patients receiving cA2 at 3 or 10 mg/kg with or without MTX achieved the 20% Paulus criteria for response to treatment, for a median duration of 10.4 to >18.1 weeks (P < 0.001 versus placebo). Patients receiving cA2 at 1 mg/kg without MTX became unresponsive to repeated infusions of cA2 (median duration 2.6 weeks; P=0.126 versus placebo). However, coadministration of cA2 at 1 mg/kg with MTX appeared to be synergistic, prolonging the duration of the 20% response in >60% of patients to a median of 16.5 weeks (P < 0.001 versus placebo; P=0.006 versus no MTX) and the 50% response to 12.2 weeks (P < 0.001 versus placebo; P=0.002 versus no MTX). Patients receiving placebo infusions plus suboptimal low-dose MTX continued to have active disease, with a Paulus response lasting a median of 0 weeks. A 70-90% reduction in the swollen joint count, tender joint count, and C-reactive protein level was maintained for the entire 26 weeks in patients receiving 10 mg/kg of cA2 with MTX. In general, treatment was well tolerated and stable blood levels of cA2 were achieved in all groups, except for the group receiving 1 mg/kg of cA2 alone, at which dosage antibodies to cA2 were observed in approximately 50% of the patients.

CONCLUSIONS

Multiple infusions of cA2 were effective and well tolerated, with the best results occurring at 3 and 10 mg/kg either alone or in combination with MTX in approximately 60% of patients with active RA despite therapy with low-dose MTX. When cA2 at 1 mg/kg was given with low-dose MTX, synergy was observed. The results of the trial provide a strategy for further evaluation of the efficacy and safety of longer-term treatment with cA2.

Epigenetic mechanisms integrate genetic and environmental causes of disease, but comprehensive genome-wide analyses of epigenetic modifications have not yet demonstrated robust association with common diseases. Using Illumina HumanMethylation450 arrays on 354 anti-citrullinated protein antibody-associated rheumatoid arthritis cases and 337 controls, we identified two clusters within the major histocompatibility complex (MHC) region whose differential methylation potentially mediates genetic risk for rheumatoid arthritis. To reduce confounding factors that have hampered previous epigenome-wide studies, we corrected for cellular heterogeneity by estimating and adjusting for cell-type proportions in our blood-derived DNA samples and used mediation analysis to filter out associations likely to be a consequence of disease. Four CpGs also showed an association between genotype and variance of methylation. The associations for both clusters replicated at least one CpG (P < 0.01), with the rest showing suggestive association, in monocyte cell fractions in an independent cohort of 12 cases and 12 controls. Thus, DNA methylation is a potential mediator of genetic risk.

Tumour necrosis factor alpha (TNF alpha) is a critical inflammatory mediator in rheumatoid arthritis, and may therefore be a useful target for specific immunotherapy. In support of this hypothesis, we previously observed beneficial responses in patients with active rheumatoid arthritis after open-label administration of a chimeric monoclonal antibody to TNF alpha (cA2). We now report the results of a four-centre, randomised double-blind trial of a single infusion of 1 or 10 mg/kg cA2 compared with placebo in 73 patients with active rheumatoid arthritis. The primary endpoint of the study was the achievement at week 4 of a Paulus 20% response, an amalgam of six clinical, observational, and laboratory variables. Intention-to-treat analysis of data from individual patients showed only 2 of 24 placebo recipients responding at this time, compared with 11 of 25 patients treated with low-dose cA2 (p = 0.0083) and 19 of 24 patients treated with high-dose cA2 (p < 0.0001). Over half of the high-dose cA2 patients responded by the more stringent 50% Paulus criteria at this time (p = 0.0005). The magnitude of these responses was impressive, with maximum mean improvements in individual disease-activity assessments, such as tender or swollen-joint counts and in serum C-reactive protein, exceeding 60% for patients on high-dose treatment. There were two severe adverse events. 1 patient on 1 mg/kg cA2 developed pneumonia ("possibly" treatment-related) and 1 on 10 mg/kg had a fracture ("probably not" treatment-related). The results provide the first good evidence that specific cytokine blockade can be effective in human inflammatory disease and define a new direction for the treatment of rheumatoid arthritis.

Rheumatoid arthritis is a systemic inflammatory disorder that mainly affects the diarthrodial joint. It is the most common form of inflammatory arthritis, and has a substantial societal effect in terms of cost, disability, and lost productivity. Although the pathogenesis of rheumatoid arthritis remains incompletely understood, much insight into the cellular and molecular mechanisms involved has been gained in the past decade. On the basis of these insights, new therapies have been developed, and clinical trials have shown the efficacy of aggressive treatment of patients with active disease. In this review, we discuss improvements in our understanding of the pathophysiology of inflammatory synovitis in rheumatoid arthritis, and improvements in therapy for patients with the disorder. The past decade has seen substantial advances in these areas. Future studies will be directed at improving methods for early diagnosis and identification of patients with progressive disease, and at improving methods to identify candidates for subclasses of disease-modifying antirheumatic drugs (DMARDs). Long-term safety and efficacy data for the new DMARD agents and combination regimens will also further delineate efficacy and toxicity and thus the appropriate clinical context for use of these therapeutic approaches. The continuing elucidation of pathophysiological pathways relevant in rheumatoid arthritis, coupled with continuing advances in biotechnology and rational drug design, offer substantial hope for the continued development of increasingly potent and specific pharmacotherapy for treatment of rheumatoid arthritis.

OBJECTIVE

To develop evidence-based EULAR recommendations for cardiovascular (CV) risk management in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA).

METHODS

A multidisciplinary expert committee was convened as a task force of the EULAR Standing Committee for Clinical Affairs (ESCCA), comprising 18 members including rheumatologists, cardiologists, internists and epidemiologists, representing nine European countries. Problem areas and related keywords for systematic literature research were identified. A systematic literature research was performed using MedLine, Embase and the Cochrane library through to May 2008. Based on this literature review and in accordance with the EULAR's "standardised operating procedures", the multidisciplinary steering committee formulated evidence-based and expert opinion-based recommendations for CV risk screening and management in patients with inflammatory arthritis.

RESULTS

Annual CV risk assessment using national guidelines is recommended for all patients with RA and should be considered for all patients with AS and PsA. Any CV risk factors identified should be managed according to local guidelines. If no local guidelines are available, CV risk management should be carried out according to the SCORE function. In addition to appropriate CV risk management, aggressive suppression of the inflammatory process is recommended to further lower the CV risk.

CONCLUSIONS

Ten recommendations were made for CV risk management in patients with RA, AS and PsA. The strength of the recommendations differed between RA on the one hand, and AS and PsA, on the other, as evidence for an increased CV risk is most compelling for RA.

We examine here several diseases that are associated with inappropriate activation of the chemokine network. Detailed comment has been restricted to pathological states for which there are compelling data either from clinical observations or animal models. These include cardiovascular disease, allergic inflammatory disease, transplantation, neuroinflammation, cancer and HIV-associated disease. Discussion focuses on therapeutic directions in which the rapidly evolving chemokine field appears to be headed.

OBJECTIVE

To investigate the presence and role of interleukin-17 (IL-17) in rheumatoid arthritis (RA), and its regulation by antiinflammatory cytokines.

METHODS

The production of IL-17 was measured in supernatants of RA, osteoarthritis (OA), and normal synovial tissue pieces cultured ex vivo. Quantification of IL-17 was performed using a specific biologic assay. IL-17 gene expression was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR)-techniques. Immunohistochemistry was used to evaluate the frequency of IL-17-positive cells in synovium. The secretion of IL-17 by synovium was measured in the presence of IL-4, IL-13, and IL-10. In addition, the contributions of exogenous and endogenous IL-17 to IL-6 production by RA synovium were studied.

RESULTS

Functional IL-17 was spontaneously produced by 16 of 18 RA (mean +/- SEM 41.7+/-11.4 units/ml), 2 of 12 OA (5.3+/-4.5 units/ml), and 0 of 3 normal synovial explant cultures. IL-17 messenger RNA expression was demonstrated by RT-PCR in 4 of 5 RA and 0 of 3 OA synovial samples. By immunostaining of RA synovium, IL-17-producing cells were found in the T cell-rich area. Addition of both IL-4 and IL-13 completely inhibited the production of IL-17, whereas IL-10 had no effect. Addition of exogenous IL-17 to RA synovium resulted in an increase in IL-6 production, whereas that of a blocking anti-IL-17 antibody reduced production of IL-6.

CONCLUSIONS

The T cell cytokine IL-17 was found to be highly produced by RA, but not by OA, synovium. Its production and function were down-regulated by IL-4 and IL-13. These results indicate that IL-17 contributes to the active, proinflammatory pattern that is characteristic of RA. Through the contribution of IL-17, some Th1-like T cells appear to mediate synovial inflammation.

OBJECTIVE

Tumor necrosis factor (TNF) is an important proinflammatory cytokine that mediates inflammatory synovitis and articular matrix degradation in rheumatoid arthritis (RA). We investigated the ability of adalimumab, a human anti-TNF monoclonal antibody, to inhibit the progression of structural joint damage, reduce the signs and symptoms, and improve physical function in patients with active RA receiving concomitant treatment with methotrexate (MTX).

METHODS

In this multicenter, 52-week, double-blind, placebo-controlled study, 619 patients with active RA who had an inadequate response to MTX were randomized to receive adalimumab 40 mg subcutaneously every other week (n = 207), adalimumab 20 mg subcutaneously every week (n = 212), or placebo (n = 200) plus concomitant MTX. The primary efficacy end points were radiographic progression at week 52 (total Sharp score by a modified method [TSS]), clinical response at week 24 (improvements of at least 20% in the American College of Rheumatology core criteria [ACR20]), and physical function at week 52 (disability index of the Health Assessment Questionnaire [HAQ]).

RESULTS

At week 52, there was statistically significantly less radiographic progression, as measured by the change in TSS, in the patients receiving adalimumab either 40 mg every other week (mean +/- SD change 0.1 +/- 4.8) or 20 mg weekly (0.8 +/- 4.9) as compared with that in the placebo group (2.7 +/- 6.8) (P < or = 0.001 for each comparison). In addition, there were statistically significant changes in the components of the TSS. At week 24, ACR20 responses were achieved by 63% and 61% of patients in the adalimumab 40 mg every other week and 20 mg weekly groups, respectively, versus 30% of patients in the placebo group (P < or = 0.001 for each comparison). At week 52, ACR20 responses were achieved by 59% and 55% of patients taking adalimumab 40 mg every other week and 20 mg weekly, respectively, versus 24% of patients taking placebo (P < or = 0.001 for each comparison). At week 52, physical function as measured by the HAQ demonstrated statistically significant improvement with adalimumab 40 mg every other week and 20 mg weekly compared with placebo (mean change in HAQ score -0.59 and -0.61, respectively, versus -0.25; P < or = 0.001 for each comparison). A total of 467 patients (75.4%) completed 52 weeks of treatment. Adalimumab was generally well tolerated. Discontinuations occurred in 22.0% of adalimumab-treated patients and in 30.0% of placebo-treated patients. The rate of adverse events (both serious and nonserious) was comparable in the adalimumab and placebo groups, although the proportion of patients reporting serious infections was higher in patients receiving adalimumab (3.8%) than in those receiving placebo (0.5%) (P < or = 0.02), and was highest in the patients receiving 40 mg every other week.

CONCLUSIONS

In this 52-week trial, adalimumab was more effective than placebo at inhibiting the progression of structural joint damage, reducing the signs and symptoms, and improving physical function in patients with active RA who had demonstrated an incomplete response to MTX.

BACKGROUND

A substantial number of patients with rheumatoid arthritis have an inadequate or unsustained response to tumor necrosis factor alpha (TNF-alpha) inhibitors. We conducted a randomized, double-blind, phase 3 trial to evaluate the efficacy and safety of abatacept, a selective costimulation modulator, in patients with active rheumatoid arthritis and an inadequate response to at least three months of anti-TNF-alpha therapy.

METHODS

Patients with active rheumatoid arthritis and an inadequate response to anti-TNF-alpha therapy were randomly assigned in a 2:1 ratio to receive abatacept or placebo on days 1, 15, and 29 and every 28 days thereafter for 6 months, in addition to at least one disease-modifying antirheumatic drug. Patients discontinued anti-TNF-alpha therapy before randomization. The rates of American College of Rheumatology (ACR) 20 responses (indicating a clinical improvement of 20 percent or greater) and improvement in functional disability, as reflected by scores for the Health Assessment Questionnaire (HAQ) disability index, were assessed.

RESULTS

After six months, the rates of ACR 20 responses were 50.4 percent in the abatacept group and 19.5 percent in the placebo group (P<0.001); the respective rates of ACR 50 and ACR 70 responses were also significantly higher in the abatacept group than in the placebo group (20.3 percent vs. 3.8 percent, P<0.001; and 10.2 percent vs. 1.5 percent, P=0.003). At six months, significantly more patients in the abatacept group than in the placebo group had a clinically meaningful improvement in physical function, as reflected by an improvement from baseline of at least 0.3 in the HAQ disability index (47.3 percent vs. 23.3 percent, P<0.001). The incidence of adverse events and peri-infusional adverse events was 79.5 percent and 5.0 percent, respectively, in the abatacept group and 71.4 percent and 3.0 percent, respectively, in the placebo group. The incidence of serious infections was 2.3 percent in each group.

CONCLUSIONS

Abatacept produced significant clinical and functional benefits in patients who had had an inadequate response to anti-TNF-alpha therapy.

BACKGROUND

Rheumatoid arthritis may be associated with an increased risk of cardiovascular disease. We compared the incidence rates of myocardial infarction and stroke in subjects with and without rheumatoid arthritis.

RESULTS

A prospective cohort study was conducted among the 114 342 women participating in the Nurses' Health Study who were free of cardiovascular disease and rheumatoid arthritis at baseline in 1976. All self-reported cases of rheumatoid arthritis were confirmed by medical record review. Fatal and nonfatal myocardial infarctions and strokes were similarly confirmed. Multivariate pooled logistic regression was used to adjust for potential cardiovascular risk factors. Five hundred twenty-seven incident cases of rheumatoid arthritis and 3622 myocardial infarctions and strokes were confirmed during 2.4 million person-years of follow-up. The adjusted relative risk of myocardial infarction in women with rheumatoid arthritis compared with those without was 2.0 (95% confidence interval [CI], 1.23 to 3.29). For stroke, the adjusted relative risk was 1.48 (95% CI, 0.70 to 3.12). Women who had rheumatoid arthritis for at least 10 years had a risk for myocardial infarction of 3.10 (95% CI, 1.64 to 5.87).

CONCLUSIONS

In this large prospective cohort of women, participants with rheumatoid arthritis had a significantly increased risk of myocardial infarction but not stroke compared with those without rheumatoid arthritis. If these data are confirmed, aggressive coronary heart disease prevention strategies should be tested for persons with rheumatoid arthritis.

The irreversible destruction of the cartilage, tendon, and bone that comprise synovial joints is the hallmark of both rheumatoid arthritis (RA) and osteoarthritis (OA). While cartilage is made up of proteoglycans and type II collagen, tendon and bone are composed primarily of type I collagen. RA is an autoimmune disease afflicting numerous joints throughout the body; in contrast, OA develops in a small number of joints, usually resulting from chronic overuse or injury. In both diseases, inflammatory cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) stimulate the production of matrix metalloproteinases (MMPs), enzymes that can degrade all components of the extracellular matrix. The collagenases, MMP-1 and MMP-13, have predominant roles in RA and OA because they are rate limiting in the process of collagen degradation. MMP-1 is produced primarily by the synovial cells that line the joints, and MMP-13 is a product of the chondrocytes that reside in the cartilage. In addition to collagen, MMP-13 also degrades the proteoglycan molecule, aggrecan, giving it a dual role in matrix destruction. Expression of other MMPs such as MMP-2, MMP-3 and MMP-9, is also elevated in arthritis and these enzymes degrade non-collagen matrix components of the joints. Significant effort has been expended in attempts to design effective inhibitors of MMP activity and/or synthesis with the goal of curbing connective tissues destruction within the joints. To date, however, no effective clinical inhibitors exist. Increasing our knowledge of the crystal structures of these enzymes and of the signal transduction pathways and molecular mechanisms that control MMP gene expression may provide new opportunities for the development of therapeutics to prevent the joint destruction seen in arthritis.

Network meta-analysis synthesizes direct and indirect evidence in a network of trials that compare multiple interventions and has the potential to rank the competing treatments according to the studied outcome. Despite its usefulness network meta-analysis is often criticized for its complexity and for being accessible only to researchers with strong statistical and computational skills. The evaluation of the underlying model assumptions, the statistical technicalities and presentation of the results in a concise and understandable way are all challenging aspects in the network meta-analysis methodology. In this paper we aim to make the methodology accessible to non-statisticians by presenting and explaining a series of graphical tools via worked examples. To this end, we provide a set of STATA routines that can be easily employed to present the evidence base, evaluate the assumptions, fit the network meta-analysis model and interpret its results.

Among the fatty acids, it is the omega-3 polyunsaturated fatty acids (PUFA) which possess the most potent immunomodulatory activities, and among the omega-3 PUFA, those from fish oil-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)--are more biologically potent than alpha-linolenic acid (ALA). Some of the effects of omega-3 PUFA are brought about by modulation of the amount and types of eicosanoids made, and other effects are elicited by eicosanoid-independent mechanisms, including actions upon intracellular signaling pathways, transcription factor activity and gene expression. Animal experiments and clinical intervention studies indicate that omega-3 fatty acids have anti-inflammatory properties and, therefore, might be useful in the management of inflammatory and autoimmune diseases. Coronary heart disease, major depression, aging and cancer are characterized by an increased level of interleukin 1 (IL-1), a proinflammatory cytokine. Similarly, arthritis, Crohn's disease, ulcerative colitis and lupus erythematosis are autoimmune diseases characterized by a high level of IL-1 and the proinflammatory leukotriene LTB(4) produced by omega-6 fatty acids. There have been a number of clinical trials assessing the benefits of dietary supplementation with fish oils in several inflammatory and autoimmune diseases in humans, including rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, lupus erythematosus, multiple sclerosis and migraine headaches. Many of the placebo-controlled trials of fish oil in chronic inflammatory diseases reveal significant benefit, including decreased disease activity and a lowered use of anti-inflammatory drugs.