Interleukin-6 blockade raises LDL via reduced catabolism rather than via increased synthesis: a cytokine-specific mechanism for cholesterol changes in rheumatoid arthritis.

OBJECTIVES: Patients with rheumatoid arthritis (RA) have reduced serum low-density lipoprotein cholesterol (LDL-c), which increases following therapeutic IL-6 blockade. We aimed to define the metabolic pathways underlying these lipid changes. METHODS: In the KALIBRA study, lipoprotein kinetic studies were performed on 11 patients with severe active RA at baseline and following three intravenous infusions of the IL-6R blocker tocilizumab. The primary outcome measure was the fractional catabolic rate (FCR) of LDL. RESULTS: Serum total cholesterol (4.8 vs 5.7 mmol/L, p=0.003), LDL-c (2.9 vs 3.4 mmol/L, p=0.014) and high-density lipoprotein cholesterol (1.23 vs 1.52 mmol/L, p=0.006) increased following tocilizumab therapy. The LDL FCR fell from a state of hypercatabolism to a value approximating that of the normal population (0.53 vs 0.27 pools/day, p=0.006). Changes in FCR correlated tightly with changes in serum LDL-c and C-reactive protein but not Clinical Disease Activity Index. CONCLUSIONS: Patients with RA have low serum LDL-c due to hypercatabolism of LDL particles. IL-6 blockade normalises this catabolism in a manner associating with the acute phase response (and thus hepatic IL-6 signalling) but not with RA disease activity as measured clinically. We demonstrate that IL-6 is one of the key drivers of inflammation-driven dyslipidaemia.

MicroRNA-34a dependent regulation of AXL controls the activation of dendritic cells in inflammatory arthritis.

Current treatments for rheumatoid arthritis (RA) do not reverse underlying aberrant immune function. A genetic predisposition to RA, such as HLA-DR4 positivity, indicates that dendritic cells (DC) are of crucial importance to pathogenesis by activating auto-reactive lymphocytes. Here we show that microRNA-34a provides homoeostatic control of CD1c+ DC activation via regulation of tyrosine kinase receptor AXL, an important inhibitory DC auto-regulator. This pathway is aberrant in CD1c+ DCs from patients with RA, with upregulation of miR-34a and lower levels of AXL compared to DC from healthy donors. Production of pro-inflammatory cytokines is reduced by ex vivo gene-silencing of miR-34a. miR-34a-deficient mice are resistant to collagen-induced arthritis and interaction of DCs and T cells from these mice are reduced and do not support the development of Th17 cells in vivo. Our findings therefore show that miR-34a is an epigenetic regulator of DC function that may contribute to RA.

Ankylosing spondylitis patients display altered dendritic cell and T cell populations that implicate pathogenic roles for the IL-23 cytokine axis and intestinal inflammation.

OBJECTIVE: AS is a systemic inflammatory disease of the SpA family. Polymorphisms at loci including HLA-B27, IL-23R and ERAP-1 directly implicate immune mechanisms in AS pathogenesis. Previously, in an SpA model, we identified HLA-B27-mediated effects on dendritic cells that promoted disease-associated Th17 cells. Here we extend these studies to AS patients using deep immunophenotyping of candidate pathogenic cell populations. The aim of our study was to functionally characterize the immune populations mediating AS pathology. METHODS: Using 11-parameter flow cytometry, we characterized the phenotype and functions of lymphocyte and myeloid cells from peripheral blood, and the synovial phenotype of AS patients and age-matched healthy controls. RESULTS: Significantly fewer circulating CD1c-expressing dendritic cells were observed in AS patients, offset by an increase in CD14(-) CD16(+) mononuclear cells. Ex vivo functional analysis revealed that this latter population induced CCR6 expression and promoted secretion of IL-1ß and IL-6 when co-cultured with naive CD4(+) T cells. Additionally, systemic inflammation in AS patients significantly correlated with increased proportions of activated CCR9(+) CD4(+) T cells. CONCLUSION: CD14(-) CD16(+) mononuclear cells may contribute to AS by promoting Th17 responses, and antigen-presenting cells of mucosal origin are likely to contribute to systemic inflammation in AS.

Role for TNF in atherosclerosis? Lessons from autoimmune disease.

Inflammatory pathways have been implicated in the initiation and progression of cardiovascular diseases. Accelerated atherosclerosis has been described in patients with chronic inflammatory diseases, particularly rheumatoid arthritis, disproportionate to individuals' detectable traditional vascular risk factors. This finding suggests that other pathways associated with inflammation might account for increased vascular risk in such diseases. Highly specific biologic agents can precisely block the activity of cytokines generated during inflammatory cascades; the effects of these inflammatory moieties on vascular physiology and overall risk of cardiovascular events has been directly evaluated. This review summarizes key epidemiologic, physiologic and model data, which together suggest that tumor necrosis factor, a pivotal cytokine in the inflammatory cascade, is directly involved in vascular pathophysiology and that its inhibition might confer an overall advantage to the recipient. Moreover, such data obtained in chronic inflammatory diseases likely have relevance to primary atherosclerosis.

Psoriatic arthritis: current topics.

Psoriatic arthritis is a common inflammatory arthropathy that occurs in approximately 25% of psoriasis patients. Due to significant advances in therapeutics--mainly the advent of biologic therapy--the disease has been subject to intense investigation recently. This review summarizes recent investigations of disease pathogenesis and clinical treatment. Clinical responses to tumor necrosis factor-blocking agents appear robust and superior to traditional disease-modifying drug responses, whereas other interventions, such as costimulation blockade, require more investigation. The pathogenesis of the disease appears related to T helper 17-polarized immune responses that target skin, joints, and the enthesial compartment. Finally, new insights into the disorder's genetic antecedents are emerging as more cohorts of patients undergo advanced genetic screening methods.

Do the pleiotropic effects of statins in the vasculature predict a role in inflammatory diseases?

Pleiotropic effects are now described for the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (or statins) that might have utility in the context of chronic inflammatory autoimmune disease. Here we discuss the pharmacology and established uses of statins and in this context describe potential anti-inflammatory and immune-modulatory effects. An extensive in vitro data set defines roles for statins in modifying endothelial function, particularly with respect to adhesion molecule expression and apoptosis. Broader effects on leukocyte function have now emerged including altered adhesion molecule expression, cytokine and chemokine release and modulation of development of adaptive immune responses via altered MHC class II upregulation. In vivo data in several inflammatory models, including collagen-induced inflammatory arthritis and experimental autoimmune encephalomyelitis, suggest that such effects might have immune-modulatory potential. Finally, a recent clinical trial has demonstrated immunomodulatory effects for statins in patients with rheumatoid arthritis. Together with their known vasculoprotective effects, this growing body of evidence provides compelling support for longer-term trials of statin therapy in human disease such as rheumatoid arthritis.

Trial of Atorvastatin in Rheumatoid Arthritis (TARA): double-blind, randomised placebo-controlled trial.

BACKGROUND: Rheumatoid arthritis is characterised by inflammatory synovitis, articular destruction, and accelerated atherogenesis. HMG-CoA (3-hydroxy-3-methylglutarylcoenzyme A) reductase inhibitors (statins) mediate clinically significant vascular risk reduction in patients without inflammatory disease and might have immunomodulatory function. We postulated that statins might reduce inflammatory factors in rheumatoid arthritis and modify surrogates for vascular risk. METHODS: 116 patients with rheumatoid arthritis were randomised in a double-blind placebo-controlled trial to receive 40 mg atorvastatin or placebo as an adjunct to existing disease-modifying antirheumatic drug therapy. Patients were followed up over 6 months and disease activity variables and circulating vascular risk factors were measured. Coprimary outcomes were change in disease activity score (DAS28) and proportion meeting EULAR (European League Against Rheumatism) response criteria. Analysis was by intention to treat. FINDINGS: At 6 months, DAS28 improved significantly on atorvastatin (-0.5, 95% CI -0.75 to -0.25) compared with placebo (0.03, -0.23 to 0.28; difference between groups -0.52, 95% CI -0.87 to -0.17, p=0.004). DAS28 EULAR response was achieved in 18 of 58 (31%) patients allocated atorvastatin compared with six of 58 (10%) allocated placebo (odds ratio 3.9, 95% CI 1.42-10.72, p=0.006). C-reactive protein and erythrocyte sedimentation rate declined by 50% and 28%, respectively, relative to placebo (p<0.0001, p=0.005, respectively). Swollen joint count also fell (-2.69 vs -0.53; mean difference -2.16, 95% CI -3.67 to -0.64, p=0.0058). Adverse events occurred with similar frequency in patients allocated atorvastatin and placebo. INTERPRETATION: These data show that statins can mediate modest but clinically apparent anti-inflammatory effects with modification of vascular risk factors in the context of high-grade autoimmune inflammation.

Explaining how "high-grade" systemic inflammation accelerates vascular risk in rheumatoid arthritis.

There is intense interest in mechanisms whereby low-grade inflammation could interact with conventional and novel vascular risk factors to promote the atheromatous lesion. Patients with rheumatoid arthritis (RA), who by definition manifest persistent high levels of inflammation, are at greater risk of developing cardiovascular disease. Mechanisms mediating this enhanced risk are ill defined. On the basis of available evidence, we argue here that the systemic inflammatory response in RA is critical to accelerated atherogenesis operating via accentuation of established and novel risk factor pathways. By implication, long-term suppression of the systemic inflammatory response in RA should be effective in reducing risk of coronary heart disease. Early epidemiological observational and clinical studies are commensurate with this hypothesis. By contrast, risk factor modulation with conventional agents, such as statins, may provide unpredictable clinical benefit in the context of uncontrolled systemic inflammatory parameters. Unraveling such complex relationships in which exaggerated inflammation-risk factor interactions are prevalent may elicit novel insights to effector mechanisms in vascular disease generally.

A novel anti-inflammatory role for simvastatin in inflammatory arthritis.

3-Hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) exert favorable effects on lipoprotein metabolism, but may also possess anti-inflammatory properties. Therefore, we explored the activities of simvastatin, a lipophilic statin, in a Th1-driven model of murine inflammatory arthritis. We report in this study that simvastatin markedly inhibited not only developing but also clinically evident collagen-induced arthritis in doses that were unable to significantly alter cholesterol concentrations in vivo. Ex vivo analysis demonstrated significant suppression of collagen-specific Th1 humoral and cellular immune responses. Moreover, simvastatin reduced anti-CD3/anti-CD28 proliferation and IFN-gamma release from mononuclear cells derived from peripheral blood and synovial fluid. Proinflammatory cytokine production in vitro by T cell contact-activated macrophages was suppressed by simvastatin, suggesting that such observations have direct clinical relevance. These data clearly illustrate the therapeutic potential of statin-sensitive pathways in inflammatory arthritis.

"5D" Outcome in 52 patients with rheumatoid arthritis surviving 20 years after initial disease modifying antirheumatic drug therapy.

OBJECTIVE: Evaluation of a complex and variable disease such as rheumatoid arthritis (RA) poses a challenge particularly over the medium to long term. A practical framework to evaluate clinically relevant outcomes over the long term is the "5D" approach of Fries, described in 1980. We describe the 20 year outcome in 52 survivors of a 123 patient cohort in terms of change in discomfort, disability, drug side effects, dollar costs, and deaths. METHODS: We studied 123 patients with RA allocated to their first disease modifying antirheumatic drug (DMARD) between 1977 and 1979. All were under the overall care of one physician over the 20 years and were maintained where possible taking a single DMARD. Baseline demographic variables, the Ritchie Articular Index (RAI), Lee functional index, and erythrocyte sedimentation rate (ESR) were initially recorded. The extent to which the demographic and disease variables contributed to need for joint replacement surgery was assessed. Therapies for comorbidity were also documented. RESULTS: At cohort inception mean age was 50 years, RAI was 35, and median disease duration 5.5 years. F:M ratio was 90:33; 96% of patients were positive for rheumatoid factor (RF). Initial median ESR was 55 mm/h. At 20 years, 9 patients (7% of original cohort, 14% of survivors) were lost to followup and 62 (50%) had died. In the 52 survivors RAI, a surrogate for disability, showed a significant improvement (p < 0.0001), but disability measured by Lee functional index showed a deterioration (p = 0.018); 50% underwent joint replacement surgery. Initial ESR and mean ESR over the first 10 years of followup were significantly higher in those who required surgery. Nonsteroidal antiinflammatory drug (NSAID) use declined, but at least 2 deaths and 4 renal deaths that may have been related to therapy were attributed to NSAID use. No unexpected DMARD toxicity or mortality occurred. Concomitant therapy for comorbidity, in particular for cardiovascular disease, osteoporosis, and gastrointestinal disease, increased: more than 60% were on these therapies at 20 year followup. CONCLUSION: Strategies to improve the outcome of RA in all dimensions should include: earlier referral for expert assessment; avoidance of NSAID gastrointestinal and nephrotoxicity; a more intensive effort to identify effective management of comorbidity and those likely to have a poor outcome. Such patients require sustained, intensive therapy to minimize later disability.