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ID PMID Title PublicationDate abstract
21814017 [RANKL signal and osteoimmunology]. 2011 Aug The bony skeleton enables the locomotive activity, the storage of calcium, and the harboring of the hematopoietic stem cells from which blood and immune cells are derived. The immune and skeletal systems share various molecules including cytokines, signaling molecules, transcription factors and membrane receptors. Investigation into rheumatoid arthritis (RA) as well as cloning of RANKL and various bone phenotypes found in immune-compromised gene deficient mice has highlighted the importance of the dynamic interplay between the both systems. These findings have recently led to both the emergence and subsequent rapid evolution of the field of osteoimmunology. The scope of osteoimmunology has been extended to encompass a wide range of molecular and cellular interactions, the elucidation of which will provide a scientific basis for future therapeutic approaches to diseases related to the immune and skeletal systems.
21601539 Altered glycosylation and expression of plasma alpha-1-acid glycoprotein and haptoglobin i 2011 Jun 15 Altered glycosylation patterns in plasma proteins are found to be associated with the pathogenesis of various malignancies and autoimmune disorders. Our previous studies demonstrated the occurrence of some differentially glycosylated plasma proteins in rheumatoid arthritis (RA) patients. The current study was conducted to evaluate the alterations in expression and glycosylation of major acute phase proteins from wheat germ agglutinin enriched RA patients' plasma. Immunoblotting studies revealed a significant enhancement in the plasma levels of alpha-1 acid glycoprotein (AGP) and haptoglobin (Hp) in RA patients with respect to healthy controls. Monosaccharide analysis by high performance anion exchange-chromatography with pulse amperometric detection showed significant variations in the relative percentage of galactose, glucosamine and mannose in AGP and of mannose in Hp in RA patients. Altered patterns of mannosylation in AGP and Hp were also established by enzyme linked immunosorbent assay and Western blotting using Concanavalin-A lectin. These results could give information for understanding the disease pathogenesis and may provide an insight into the development and progression of the disease.
21360522 Tumor necrosis factor therapy and the risk of serious infection and malignancy in patients 2011 Jun OBJECTIVE: To conduct a meta-analysis of the rates of serious infection and malignancy in patients with early rheumatoid arthritis (RA) who have started anti-tumor necrosis factor (anti-TNF) therapy and had not received treatment with disease-modifying antirheumatic drugs (DMARDs) or methotrexate (MTX). METHODS: A systematic literature search was conducted through the summer of 2009. All studies included were randomized, double-blind, placebo-controlled trials involving patients with early RA who were started on anti-TNF therapy without prior DMARD/MTX use. Six trials met the inclusion criteria for the meta-analysis, comprising a total of 2,183 patients receiving biologic therapy and 1,236 patients receiving MTX. The data extracted were from published trials. RESULTS: A pooled odds ratio (OR) (determined using Mantel-Haenszel methods, with a continuity correction designed for sparse data) was calculated for serious infections (requiring hospitalization) and malignancies, comparing anti-TNF therapy to MTX control. The pooled OR for serious infections was 1.28 (95% confidence interval [95% CI] 0.82-2.00) and that for malignancies was 1.08 (95% CI 0.50-2.32). There was no significant difference in either the rate of serious infections or the rate of malignancies between the anti-TNF therapy group and the control group. CONCLUSION: Whereas other meta-analyses have shown an increased risk of serious infection and malignancy in patients receiving anti-TNF therapy, the results of the present meta-analysis show that there is not an increased risk when the patients have early disease and have not previously been treated with DMARDs and/or MTX.
22231145 Heme oxygenase 1 attenuates interleukin-1β-induced cytosolic phospholipase A2 expression 2012 Jul OBJECTIVE: Reactive oxygen species (ROS) produced by cytokines induce the expression of inflammatory mediators in rheumatoid arthritis (RA). Heme oxygenase 1 (HO-1) exerts an antiinflammatory effect. The aim of this study was to examine the mechanisms underlying interleukin-1β (IL-1β)-induced cytosolic phospholipase A2 (cPLA2) expression through ROS generation as modulated by HO-1 in RA synovial fibroblasts (RASFs). METHODS: IL-1β-induced ROS generation was determined by flow cytometry. The involvement of MAPKs and NADPH oxidase (NOX)/ROS in IL-1β-induced cPLA2 expression was investigated using pharmacologic inhibitors and transfection with small interfering RNAs (siRNAs) and was analyzed by Western blotting and promoter assay. Overexpression of HO-1 was performed by transfection of RASFs with a recombinant adenovirus containing human HO-1 plasmid. SCID mice with inflammation caused by IL-1β were infected with adenovirus containing HO-1. Histologic characterization of joint inflammation and local expression of cPLA2 were evaluated after treatment. RESULTS: IL-1β-induced cPLA2 expression was mediated through NOX activation/ROS production, which was attenuated by N-acetylcysteine (NAC; a scavenger of ROS), the inhibitors of NOX (diphenyleneiodonium chloride and apocynin), MEK-1/2 (U0126), and JNK-1/2 (SP600125), transfection with the respective siRNAs, and the overexpression of HO-1 in RASFs. IL-1β-induced cPLA2 expression was mediated through recruitment of activator protein 1 (AP-1) to the cPLA2 promoter region, which was attenuated by NAC and overexpression of HO-1. Furthermore, HO-1 overexpression inhibited IL-1β-mediated cPLA2 expression in SCID mice. CONCLUSION: In RASFs, IL-1β induced cPLA2 expression via activation of p42/p44 MAPK and JNK-1/2, leading to p47phox phosphorylation, ROS production, and AP-1 activation. The induction of HO-1 exerted protective effects on the pathogenesis of RA.
22170561 CD147 induces angiogenesis through a vascular endothelial growth factor and hypoxia-induci 2012 Jun OBJECTIVE: Rheumatoid arthritis (RA) is an inflammatory and angiogenic disease. However, the molecular mechanisms that promote angiogenesis in RA have not been clearly identified. Our objective was to study the role of CD147 in angiogenesis and determine whether the strategy in which CD147 is suppressed might be useful in reducing angiogenesis in RA. METHODS: Correlations among expression levels of CD147, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1α (HIF-1α) were determined by immunohistochemistry staining. RA fibroblast-like synoviocytes (FLS) cells were cultured under various conditions, and the production of VEGF and HIF-1α was examined by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. The SCID mouse coimplantation model of RA (SCID-HuRAg) was established, mice were treated with CD147 monoclonal antibody, infliximab, or both CD147 and infliximab, and the volume of the grafts and the average vascular density were measured and analyzed. Western blot analyses were performed to examine the potential signaling pathways. RESULTS: The expression levels of CD147 showed significantly positive correlations with VEGF and HIF-1α levels, as well as with vascular density, in RA synovium. After small interfering RNA transfection or after addition of specific antibodies for CD147, the production of VEGF and HIF-1α were significantly reduced. The expression of VEGF and HIF-1α decreased more after CD147 inhibition than after infliximab treatment in the engrafted tissues in SCID-HuRAg mice. The phosphatidylinositol 3-kinase/Akt pathway may be involved in this process. CONCLUSION: CD147 induces up-regulation of VEGF and HIF-1α in RA FLS, further promotes angiogenesis, and leads to the persistence of synovitis. Inhibition of CD147 may be a promising target for novel therapeutic strategies.
22427827 Non-enzymatic decomposition of collagen fibers by a biglycan antibody and a plausible mech 2012 Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory and destructive joint disorder that affects tens of millions of people worldwide. Normal healthy joints maintain a balance between the synthesis of extracellular matrix (ECM) molecules and the proteolytic degradation of damaged ones. In the case of RA, this balance is shifted toward matrix destruction due to increased production of cleavage enzymes and the presence of (autoimmune) immunoglobulins resulting from an inflammation induced immune response. Herein we demonstrate that a polyclonal antibody against the proteoglycan biglycan (BG) causes tissue destruction that may be analogous to that of RA affected tissues. The effect of the antibody is more potent than harsh chemical and/or enzymatic treatments designed to mimic arthritis-like fibril de-polymerization. In RA cases, the immune response to inflammation causes synovial fibroblasts, monocytes and macrophages to produce cytokines and secrete matrix remodeling enzymes, whereas B cells are stimulated to produce immunoglobulins. The specific antigen that causes the RA immune response has not yet been identified, although possible candidates have been proposed, including collagen types I and II, and proteoglycans (PG's) such as biglycan. We speculate that the initiation of RA associated tissue destruction in vivo may involve a similar non-enzymatic decomposition of collagen fibrils via the immunoglobulins themselves that we observe here ex vivo.
21982911 Determination of four pyridine alkaloids from Tripterygium wilfordii Hook. f. in human pla 2011 Nov 15 A novel liquid chromatography-atmospheric-pressure chemical ionization-mass spectrometry (LC-APCI/MS) method was developed and validated for the simultaneous determination of four sesquiterpene pyridine alkaloids (wilfortrine, wilfordine, wilforgine and wilforine) in human plasma. The chromatographic separation was performed on a Shim-pack XR-ODS column using an ammonium acetate buffer solution-acetonitrile in a gradient program. The detection was achieved by an ion trap mass spectrometry in the positive selected ion monitoring (SIM) mode. The method utilized acetonitrile as protein precipitation solvent and followed by solid-phase extraction (SPE). Calibration curves were linear for the four alkaloids over the range of 0.5-100.0 μg/L with the limits of quantification of 0.5 μg/L, while the method exhibited the recovery of 86.5-98.6%, intra- and inter-day RSDs of less than 8.2% and 12.8%, respectively. Methodology was validated in line with the EU requirements (Commission Decision 2002/657/EC). Results of incurred samples demonstrated excellent reproducibility. To our knowledge, this is the first analytical method for simultaneous determination of the four sesquiterpene pyridine alkaloids in plasma. The method was applicable to clinical pharmaceutical research of alkaloids in rheumatoid arthritis volunteer patients after oral administrations.
22825627 Increased synovial expression of IL-27 by IL-17 in rheumatoid arthritis. 2012 Dec OBJECTIVES AND DESIGN: Interleukin (IL) 17 plays an important role in synovial inflammation and bone destruction in rheumatoid arthritis (RA), while IL-27 exerts a regulatory role in T cell-mediated immune responses. Our aim was to study the influence of IL-17 on IL-27 production in RA. MATERIALS AND METHODS: Following injection of IL-17 in the knee joint of CIA mice, synovium was examined for IL-17 and IL-27 expression by western blot, real-time PCR, and immunohistochemistry. IL-17 and IL-27 levels were measured by ELISA in mouse bone marrow-derived dendritic cells (BM-DCs) and in synovial fluid (SF) macrophages from RA patients. RESULTS: IL-17 exacerbated disease progression in CIA mice. Histological analysis showed increased pannus formation associated with cartilage and bone erosion following injection with IL-17. The expression of IL-27 was increased in CIA mice. The expression of IL-17 and IL-27 was increased more in IL-17-injected CIA mice than in control mice. The majority of cells expressing IL-27 were co-localized with synovial macrophages. Increased expression of IL-27 by application of recombinant IL-17 was confirmed in CIA BM-DCs and in SF macrophages from RA patients. CONCLUSION: IL-17 enhanced expression of IL-27 in synovial macrophages from RA patients and CIA mice, indicating an interaction between IL-17 and IL-27 as an autoregulatory mechanism.
23540824 Primary care attitudes to methotrexate monitoring. 2012 BACKGROUND: Rheumatoid arthritis affects 1% of the UK population. First-line treatment is with the immunosuppressant, methotrexate (MTX). This is generally regarded as a safe and effective medication when taken at the right dose, with appropriate monitoring. Very occasionally it causes serious harm or death. In 2006, the National Patient Safety Agency issued a safety alert following increasing reports of prescribing errors and toxicity. Over the last decade, Northwick Park Hospital has seen two MTX-related deaths and other morbidity. Repeat prescriptions and monitoring are generally undertaken in primary care, although concerns have been raised about variation in local practice. Poor communication and inadequate monitoring are safety concerns. Duplication of monitoring has cost implications. Local (hospital Shared Care Guidelines (SCG) ) and national guidelines, from the British Society of Rheumatology (BSR), on MTX monitoring are freely available and accessible. METHOD: We surveyed our local GP community to better understand their practice and establish where patient care could be improved. RESULTS: We contacted 86 practices, of which 31 replied (a response rate of 36%). On average, there was one patient on MTX per 743 in the practice (0.13%), ranging from 0-0.5%. All GPs admitted they repeated MTX prescriptions, but only 77.4% monitored these. Of those who did monitor, 58.6% were aware of local guidelines and only 48.4% were aware of national guidelines. A total of 26.7% of GPs were monitoring and prescribing MTX but not aware of any guidelines. Among this number, 37.5% did not feel they needed further education. CONCLUSION: Serious safety concerns have been raised, including the poor response rate. Any doctor prescribing MTX should also be monitoring according to guidelines. Low numbers of patients on MTX per practice are surprising, possibly reflecting inadequate records or under-diagnosis. With these data, we have encouraged commissioners to fund a computer monitoring system accessible to primary and secondary care for improved patient safety, and to ultimately save costs by reducing duplication of work.
20861148 Detection and evaluation of a drug safety signal concerning pancreatic cancer: lessons fro 2011 Jan OBJECTIVES: A high incidence of pancreatic cancer (PCa) in patients exposed to was observed in the German biologics register. To evaluate this possible safety signal, a concerted analysis with the national biologics registers in the UK and Sweden was performed. METHODS: Patients with enrolled in the British Society of Rheumatology Biologics Register (BSRBR), the Swedish Rheumatology Register (SRR) or the German Biologics Register [Rheumatoid Arthritis Observation of Biologic Therapy (RABBIT)] were analysed. The patients were exposed to biologic or conventional DMARDs. Outcomes were obtained from physician reports, health authorities and via linkage to national cancer and death registers. Age- and gender-standardized incidence ratios (SIRs) of PCa were calculated based on the expected rates available from the individual national cancer registers. RESULTS: Data from 5126 (Germany), 16 930 (UK) and 19 351 (Sweden) RA patients were available for the analysis. The highly discrepant prescription rates of LEF in the respective countries resulted in 11 343 (Germany), 30 787 (UK) and 2518 (S) patient-years of exposure to LEF. Compared with the general population, the incidence of PCa in patients ever exposed to LEF corresponded to a SIR of 3.1 (95% CI 1.3, 6.5) in Germany, 1.05 (95% CI 0.5, 2.1) in the UK and 1.8 (95% CI 0.1, 10.2) in Sweden. CONCLUSION: The results of the replication analyses do not support the hypothesis of an increased risk of PCa in patients exposed to treatment with LEF. However, they do not completely rule out concerns, and therefore further verification in other data sets is recommended.
22328739 A phase II, double-blind, randomised, placebo-controlled study of BMS945429 (ALD518) in pa 2012 Jul BACKGROUND: Interleukin 6 (IL-6) plays a key role in the inflammatory cascade in rheumatoid arthritis. BMS945429 is a humanised, monoclonal antibody that potently binds IL-6. OBJECTIVE: To conduct aphase II study to determine the efficacy and safety of BMS945429 in patients with active rheumatoid arthritis and an inadequate response to methotrexate. METHODS: Patients were randomised 1:1:1:1 to BMS945429 (80, 160 or 320 mg; administered intravenously) or placebo plus methotrexate during this 16-week, double-blind trial. The primary efficacy end point was the proportion of patients with a 20% improvement in American College of Rheumatology responses (ACR20) at week 12. Additional end points included ACR50 and ACR70 responses and 28-joint Disease Activity Scores (DAS28). RESULTS: Of 127 randomised and treated patients, 116 completed the trial. ACR20 responders at week 12 were 81% (80 mg; p<0.0001 vs placebo), 71% (160 mg; p=0.0005 vs placebo), 82% (320 mg; p<0.0001 vs placebo) and 27% (placebo), respectively. By week 16, 14% (80 mg), 28% (160 mg) and 44% (320 mg) of BMS945429 patients were in DAS28 remission (DAS28 score <2.6). Statistically significant and clinically meaningful improvements in health-related quality of life (HRQoL) were reported in all active treatment groups. Administration of BMS945429 was associated with increases in liver enzymes and in serum cholesterol. There were no serious infections, infusion reactions or apparent immunogenicity. CONCLUSIONS: In this phase II study, BMS945429 was associated with rapid and significant improvements in disease activity and HRQoL in patients with active rheumatoid arthritis and an inadequate response to methotrexate.
22411464 The human microbiome: at the interface of health and disease. 2012 Mar 13 Interest in the role of the microbiome in human health has burgeoned over the past decade with the advent of new technologies for interrogating complex microbial communities. The large-scale dynamics of the microbiome can be described by many of the tools and observations used in the study of population ecology. Deciphering the metagenome and its aggregate genetic information can also be used to understand the functional properties of the microbial community. Both the microbiome and metagenome probably have important functions in health and disease; their exploration is a frontier in human genetics.
22850274 Exaggerated circulating Th-1 cytokine response in early rheumatoid arthritis patients with 2012 Nov BACKGROUND: Immunohistochemical studies of the rheumatoid nodule (RN) suggest it is a Th1 granuloma, with focal vasculitis, yet the pathogenesis remains unclear and little is known about circulating cytokines in these patients. OBJECTIVE: We studied circulating cytokines in DMARD-naïve RA patients to investigate associations with subcutaneous RN. METHODS: 149 DMARD-naïve adults with early RA (symptom duration ≤ 2 years) were assessed using the Simplified Disease Activity Index (SDAI), and hand and feet radiographs were scored using the modified Larsen method. Circulating cytokines and growth factors representative of T-helper cell 1(Th1) and Th2 cell, macrophages, and fibroblasts were measured using the Bio-Plex® suspension array system. RESULTS: Of 149 patients, 34 (22.8%) had subcutaneous RN, and these patients had more severe disease with higher mean swollen joint counts (p=0.02), SDAI (p=0.04) and modified Larsen scores (p=0.004). There were no differences in Rheumatoid Factor or anti-cyclic citrullinated peptide antibody positivity between patients with RN and those without RN. Patients with RN showed significantly higher levels of circulating IL-12 (p=0.02), IL-2 (p=0.048), and VEGF (p=0.033) levels, with a trend towards higher levels of IL-7 (p=0.056), IFN-γ (p=0.059) and IL-8 (p=0.074) compared to those without RN. CONCLUSIONS: DMARD-naïve early RA patients with RN had more severe disease than those without RN, and showed an exaggerated circulating Th1 and macrophage cytokine profile.
22166956 Implication of clusterin in TNF-α response of rheumatoid synovitis: lesson from in vitro 2012 Feb 13 Recently clusterin (CLU) was reported to be an inhibitor of NF-κB pathway and involved in rheumatoid arthritis (RA) synovitis. This study was designed to decipher the molecular network linked to CLU expression in FLS (fibroblast-like synoviocytes) and evaluate the consequences of its low expression in conditions of TNF-α stimulation. FLS were transfected with siRNA for CLU or not and cultured for 24 and 48 h with TNF-α or not. Pan-genomic gene expression was assayed by DNA microarray. The gene network around CLU and gene interactions were analyzed with the Ingenuity Pathway Analysis software. Downregulation of CLU resulted in modification of the expression of genes known to be directly linked to CLU and for almost 5% of the tested genes (857 out of 17,225); the upregulation of a small group of gene (e.g., TIAM1) emphasizes the hypothetical role of CLU in the pseudotumoral characteristic of FLS. The comparison of gene expression with or without TNF stimulation allowed the classification of sampled with good concordance. Moreover, differential comparison showed that CLU downregulation in RA led to a profound modification of the TNF-α response as three sets of genes emerged: 497 genes modulated by siCLU transfection with TNF stimulation, 356 genes modified because of TNF stimulation only, and 484 genes modulated during TNF stimulation with CLU expression (e.g., IL-8 and Wnt signaling genes). Using a global two-way ANOVA we could identify a set of genes defining a molecular signature of TNF response directly influenced by CLU. These results (based on differential gene expression patterns) argue that CLU downregulation in FLS alters their aggressiveness in RA synovitis.
21608334 Effects of adalimumab treatment on vascular disease associated with early rheumatoid arthr 2011 Mar BACKGROUND: Increased cardiovascular morbidity has become a leading cause of mortality in rheumatoid arthritis (RA). Tumor necrosis factor-alpha (TNFa) inhibitors may influence flow-mediated vasodilation (FMD) of the brachial artery, common carotid intima-media thickness (ccIMT) and arterial stiffness indicated by pulse-wave velocity (PWV) in RA. OBJECTIVES: To assess the effects of adalimumab treatment on FMD, ccIMT and PWV in early RA. METHODS: Eight RA patients with a disease duration < or =1 year received 40 mg adalimumab subcutaneously every 2 weeks. Ultrasound was used to assess brachial FMD and ccIMT. PWV was determined by arteriograph. These parameters were correlated with C-reactive protein, vonWillebrand factor (vWF), immunoglobulin M (IgM)-rheumatoid factor (RF), anti-CCP levels and 28-joint disease activity score (DAS28). RESULTS: Adalimumab therapy successfully ameliorated arthritis as it decreased CRP levels (P = 0.04) and DAS28 (P < 0.0001). Endothelial function (FMD) improved in comparison to baseline (P < 0.05). ccIMT decreased after 24 weeks, indicating a mean 11.9% significant improvement (P = 0.002). Adalimumab relieved arterial stiffness (PWV) after 24 weeks. Although plasma vWF levels decreased only non-significantly after 12 weeks of treatment, an inverse correlation was found between FMD and vWF (R = -0.643, P = 0.007). FMD also inversely correlated with CRP (R = -0.596, P= 0.015). CRP and vWF also correlated with each other (R = 0.598, P = 0.014). PWV and ccIMT showed a positive correlation (R = 0.735, P = 0.038). CONCLUSIONS: Treatment with adalimumab exerted favorable effects on disease activity and endothelial dysfunction. It also ameliorated carotid atherosclerosis and arterial stiffness in patients with early RA. Early adalimumab therapy may have an important role in the prevention and management of vascular comorbidity in RA.
22660800 Serum S100A8/A9, but not follistatin-like protein 1 and interleukin 18, may be a useful bi 2012 Jul OBJECTIVE: S100A8/A9, follistatin-like protein 1, and interleukin 18 (IL-18) have been suggested as biomarkers of disease activity in patients with systemic juvenile idiopathic arthritis or adult-onset Still's disease (AOSD). We investigated the clinical significance of these factors in AOSD. METHODS: Blood samples were collected from 36 patients with AOSD, 40 patients with rheumatoid arthritis (RA), and 33 healthy controls. Of the patients with AOSD, followup samples were collected from 16 patients after resolution of disease activity. RESULTS: Serum levels of S100A8/A9 (11.77 ± 8.84 μg/ml) in AOSD patients were higher than those in RA patients (3.53 ± 3.43 μg/ml; p < 0.001) and controls (2.49 ± 1.83 μg/ml; p < 0.001). Follistatin-like protein 1 levels in AOSD were not different from those in RA and controls. IL-18 levels in AOSD (7560.3 ± 7577.6 pg/ml) were higher than those in RA (217.7 ± 292.1 pg/ml; p < 0.001) and controls (139.2 ± 86.2 pg/ml; p < 0.001). The sensitivity and specificity of IL-18 for diagnosing AOSD was highest with a cutoff value of 366.1 pg/ml. Serum S100A8/A9 correlated with leukocyte count, erythrocyte sedimentation rate, C-reactive protein, ferritin, and systemic disease score; however, IL-18 correlated only with ferritin and systemic disease score. S100A8/A9 was decreased after disease activity was resolved in followup of AOSD patients (9.96 ± 7.35 μg/ml in active AOSD vs 3.6 ± 4.77 μg/ml in resolved cases; p = 0.001). The change of S100A8/A9 was well correlated with that of systemic disease score. CONCLUSION: The data suggest that serum S100A8/A9 may be a useful biomarker for evaluating disease activity in patients with AOSD.
22615393 K-RAS GTPase- and B-RAF kinase-mediated T-cell tolerance defects in rheumatoid arthritis. 2012 Jun 19 Autoantibodies to common autoantigens and neoantigens, such as IgG Fc and citrullinated peptides, are immunological hallmarks of rheumatoid arthritis (RA). We examined whether a failure in maintaining tolerance is mediated by defects in T-cell receptor activation threshold settings. RA T cells responded to stimulation with significantly higher ERK phosphorylation (P < 0.001). Gene expression arrays of ERK pathway members suggested a higher expression of KRAS and BRAF, which was confirmed by quantitative PCR (P = 0.003), Western blot, and flow cytometry (P < 0.01). Partial silencing of KRAS and BRAF lowered activation-induced phosphorylated ERK levels (P < 0.01). In individual cells, levels of these signaling molecules correlated with ERK phosphorylation, attesting that their concentrations are functionally important. In confocal studies, B-RAF/K-RAS clustering was increased in RA T cells 2 min after T-cell receptor stimulation (P < 0.001). Overexpression of B-RAF and K-RAS in normal CD4 T cells amplified polyclonal T-cell proliferation and facilitated responses to citrullinated peptides. We propose that increased expression of B-RAF and K-RAS lowers T-cell activation thresholds in RA T cells, enabling responses to autoantigens.
22123992 Hypoxia differentially affects IL-1β-stimulated MMP-1 and MMP-13 expression of fibroblast 2012 Mar OBJECTIVES: To further understand the expression regulation of MMP-1 and MMP-13 under physiological and pathological conditions, we investigated the combined effects of hypoxia and pro-inflammatory stimuli on the expression of MMP-1 and MMP-13 in rheumatoid synovial fibroblasts. METHODS: Synovial fibroblasts were cultured under either hypoxic or normoxic conditions in the presence of IL-1β stimulation. The culture supernatant was analysed for secreted levels of VEGF, MMP-1 and MMP-13. Their gene expression was quantified with real-time and semi-quantitative PCR. Another group of cells was transfected with small-interfering RNA (siRNA) specific for hypoxia-inducible factor-1 α (HIF-1α). The protein levels of HIF-1α were detected by western blot analysis. RESULTS: In response to 10 ng/ml of IL-1β under normoxia, the levels of MMP-1 and MMP-13 increased compared with the levels observed under hypoxia. IL-1β stimulation under hypoxia induced a 2-fold increase in the level of MMP-1 and a 2-fold decrease in the level of MMP-13 compared with cells cultured under normoxia. A similar pattern of differential expression for MMP-1 and MMP-13 was observed with 1 and 5 ng/ml IL-1β, but not at 0.1 ng/ml. The differential expression of MMPs under the combined effect of IL-1β and hypoxia was significantly attenuated by silencing HIF-1α with siRNA. CONCLUSIONS: Hypoxia in arthritic joints may differentially affect the IL-1β-stimulated expression of MMP-1 and MMP-13 in rheumatoid synovial fibroblasts. This effect is dependent on HIF-1α expression. This hypoxia-mediated differential effect should be taken into consideration when testing the efficiency of therapies that target HIF-1α.
21724724 Early postoperative mortality following joint arthroplasty: a systematic review. 2011 Jul OBJECTIVE: To perform a systematic review of 30- and 90-day mortality rates in patients undergoing hip or knee arthroplasties. METHODS: Five databases were searched for English-language studies of mortality in hip or knee arthroplasties and the following data were extracted: patient characteristics (age, sex, ethnicity), arthroplasty characteristics (unilateral vs bilateral, hip vs knee), system factors (hospital volume and surgeon volume), year of study, etc. Mortality rates were compared across variable categories; proportions were compared using relative risk ratios and 95% confidence intervals. RESULTS: Out of 650 titles and abstracts, 80 studies qualified for analysis. Of these, 35%, 34%, and 31% of studies provided 30-, 90-, and > 90-day mortality rates. Overall 30-day mortality rates across all types of arthroplasties were 0.3%; 90-day, 0.7%. For those reports with specific rates, 30-day mortality was significantly higher in men than women [1.8% vs 0.4%, respectively; relative risk (RR) 3.93, 95% CI 3.30-4.68] and in bilateral versus unilateral procedures (0.5% vs 0.3%; RR 1.6, 95% CI 1.49-1.72), but no differences were noted by the underlying diagnosis of osteoarthritis (OA) versus rheumatoid arthritis (0.4% vs 0.3%; RR 0.77, 95% CI 0.48-1.24). 90-day mortality showed nonsignificant trends favoring women, OA as the underlying diagnosis, and unilateral procedures. CONCLUSION: Several demographic and surgical factors were associated with higher 30-day mortality rates following knee and hip arthroplasties. More studies are needed to examine the effect of body mass index, comorbidities, and other modifiable factors, in order to identify interventions to lower mortality rates following arthroplasty procedures.
21492465 Single nucleotide polymorphisms at the TRAF1/C5 locus are associated with rheumatoid arthr 2011 Apr 14 BACKGROUND: Genetic variants in TRAF1C5 and PTPN22 genes have been shown to be significantly associated with arthritis rheumatoid in Caucasian populations. This study investigated the association between single nucleotide polymorphisms (SNPs) in TRAF1/C5 and PTPN22 genes and rheumatoid arthritis (RA) in a Han Chinese population. We genotyped SNPs rs3761847 and rs7021206 at the TRAF1/C5 locus and rs2476601 SNP in the PTPN22 gene in a Han Chinese cohort composed of 576 patients with RA and 689 controls. The concentrations of anti-cyclic citrullinated peptide antibodies (CCP) and rheumatoid factor (RF) were determined for all affected patients. The difference between the cases and the controls was compared using χ2 analysis. RESULTS: Significant differences in SNPs rs3761847 and rs7021206 at TRAF1/C5 were observed between the case and control groups in this cohort; the allelic p-value was 0.0018 with an odds ratio of 1.28 for rs3761847 and 0.005 with an odds ratio of 1.27 for rs7021206. This significant association between rs3761847 and RA was independent of the concentrations of anti-CCP and RF. No polymorphism of rs2476601 was observed in this cohort. CONCLUSIONS: We first demonstrated that genetic variants at the TRAF1/C5 locus are significantly associated with RA in Han Chinese, suggesting that TRAF1/C5 may play a role in the development of RA in this population, which expands the pathogenesis role of TRAF1/C5 in a different ethnicity.