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ID PMID Title PublicationDate abstract
16447222 The impact of glycosylation on HLA-DR1-restricted T cell recognition of type II collagen i 2006 Feb OBJECTIVE: Type II collagen (CII) is a candidate autoantigen implicated in the pathogenesis of rheumatoid arthritis (RA). Posttranslational glycosylation of CII could alter intracellular antigen processing, leading to the development of autoimmune T cell responses. To address this possibility, we studied the intracellular processing of CII for presentation of the arthritogenic glycosylated epitope CII(259-273) to CD4 T cells in macrophages from HLA-DR1-transgenic mice. METHODS: HLA-DR1-transgenic mice were generated on a class II major histocompatibility complex-deficient background, and T cell hybridomas specific for the glycosylated and nonglycosylated epitope CII(259-273) were developed. Subcellular fractionation of macrophages was used to localize CII degradation to particular compartments and to identify the catalytic subtype of proteinases involved. RESULTS: We showed that the glycosylated CII(259-273) epitope required more extensive processing than did the nonglycosylated form of the same epitope. Dense fractions containing lysosomes were primarily engaged in the processing of CII for antigen presentation, since these compartments contained 1) enzyme activity that generated antigenic CII fragments bearing the arthritogenic glycosylated epitope, 2) the antigenic CII fragments themselves, 3) CII peptide-receptive HLA-DR1 molecules, and 4) peptide/HLA-DR1 complexes that could directly activate T cell hybridomas. Degradation of CII by dense fractions occurred optimally at pH 4.5 and was abrogated by inhibitors of serine and cysteine proteinases. CONCLUSION: Processing of the arthritogenic glycosylated CII(259-273) epitope, which is implicated in the induction of autoimmune arthritis, is more stringently regulated than is processing of the nonglycosylated form of the same epitope. Mechanisms of intracellular processing of the glycosylated epitope may constitute novel therapeutic targets for the treatment of RA.
16859835 Methtrexate-associated lymphoproliferative disorders. A clinicopathological study of 13 Ja 2006 We conducted clinicopathological and immunohistochemical analyses to investigate the prevalence of Epstein-Barr virus (EBV) among 13 cases with methotrexate (MTX)-associated lymphoproliferative disorder (LPD). The subjects of this study were four men and nine women ranging in age from 53 to 78 years (mean: 63 years). All 13 patients had received low dose MTX therapy for 1-13 years before the onset of LPD (mean: 5.8 years). LPDs were found at extranodal sites in six cases, and the disease stage was advanced in seven cases. The present study confirmed certain aspects of a previous observation made in the USA, including the following findings (i) the cases commonly showed diffuse large B-cell lymphomas (n=4) and Hodgkin lymphomas (HL) (n=3), (ii) EBV-encoded small RNA (EBER) + cells were identified in seven cases (60%), which is a much higher percentage than would be expected in lymphomas occurring in a general population, and (iii) three cases of polymorphous small lymphocytic or lymphoplasmacytic infiltrate achieved spontaneous remission of LPDs after MTX withdrawal. Of seven cases of EBER + in our series, three cases were PSLLPI, and two were HL. EBER + tumor cells were detected in only two (30%) of the seven cases with non-Hodgkin lymphomas. The present study suggests that EBV- associated non-Hodgkin lymphomas comprise only a portion of all non-Hodgkin lymphomas among MTX-associated LPDs.
15331393 Increased expression of CCL18, CCL19, and CCL17 by dendritic cells from patients with rheu 2005 Mar BACKGROUND: Dendritic cells (DC) have a role in the regulation of immunity and tolerance, attracting inflammatory cells by the production of various chemokines (CK). Fc gamma receptors (Fc gamma R) may be involved in regulation of the DC function. OBJECTIVE: To assess the expression of CK by immature (iDC) and mature DC (mDC) and its regulation by Fc gamma R in patients with RA and healthy donors (HC). METHODS: Expression of CK by DC from patients with RA and from HC was determined by real time quantitative PCR and ELISA. DC were derived from monocytes following standardised protocols. To study the potential regulation by Fc gamma R, iDC were stimulated with immune complexes (IC) during lipopolysaccharide (LPS) induced maturation. The presence of CK was studied in synovial tissue from patients with RA, osteoarthritis, and healthy subjects by RT-PCR and immunohistochemistry. RESULTS: iDC from patients with RA had markedly increased mRNA levels of the CK CCL18 and CXCL8. Upon maturation with LPS, expression of CCL18, CCL19, CXCL8, CCL3, and CCL17 increased dramatically, reaching significantly higher levels in patients with RA. Monocytes failed to express these CK, except for CXCL8 and CCL3. IC-mediated triggering of the Fc gamma R on DC from patients with highly active RA down regulated all CK, whereas the reverse was seen when DC from patients with low disease activity and healthy donors were stimulated. CCL18 was significantly increased in RA synovial tissue. CONCLUSION: Increased CK expression by DC was found in patients with RA. This expression is partly regulated by Fc gamma R triggering and results in an inhibitory DC subtype in RA upon Fc gamma R-mediated triggering.
17265571 Pooled analysis of thrombotic cardiovascular events in clinical trials of the COX-2 select 2006 Dec BACKGROUND: A pooled analysis of randomized clinical trials data was performed to compare the rate of thrombotic cardiovascular events (thrombotic events) in patients taking the COX-2 selective inhibitor (coxib) etoricoxib, a traditional NSAID, or placebo. METHODS: Data collected during all phase IIb/III etoricoxib clinical trials > or = 4 weeks in duration were evaluated. The pooled data set includes clinical information from approximately 6500 patient-years (PYs) of drug exposure in patients diagnosed with rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), or chronic low back pain (CLBP). Patients were treated with either etoricoxib (> or = 60 mg/day), the traditional NSAIDs naproxen (1000 mg/day), ibuprofen (2400 mg/day), diclofenac (150 mg/day), or placebo. The Relative risks (RRs) based on time to first occurrence of a thrombotic event in the etoricoxib group versus the comparator traditional NSAIDs or versus placebo were determined using patient-level data. RESULTS: In the pooled dataset, a total of 74 thrombotic events occurred in 69 patients. The RRs for thrombotic events were 1.11 (95%CI: 0.32, 3.81) for etoricoxib (N = 2818) versus placebo (N = 1767); 0.83 (95%CI: 0.26, 2.64) for etoricoxib (N = 1266) versus the combined non-naproxen traditional NSAID group (ibuprofen and diclofenac; N = 718); and 1.70 (95%CI: 0.91, 3.18) for etoricoxib (N = 1960) versus naproxen (N = 1497). CONCLUSIONS: There was no discernible difference in the incidence of thrombotic events in patients treated with etoricoxib versus non-naproxen traditional NSAIDs in this limited dataset. A trend toward more events with etoricoxib versus naproxen was observed. Despite the limited dataset available for this pooled analysis, these results are consistent with findings for other coxibs.
16463007 Positive effect of alendronate on bone mineral density and markers of bone turnover in pat 2006 INTRODUCTION: Alendronate has been described to have a bone-sparing effect in patients treated with moderate and high dosages of prednisone for heterogeneous diseases, however no data are available on groups of patients with the same underlying diseases who receive chronic low-dose prednisone treatment. The objective of the investigation reported here was, therefore, to study the effect of alendronate on bone mineral density (BMD) of the lumbar spine and hips in patients with rheumatoid arthritis (RA) who are on chronic low-dose prednisone treatment. METHODS: A total of 163 patients with RA, according to the ACR-criteria, were enrolled in a double-blind, placebo-controlled trial. The patients were treated with low-dose prednisone (
15983753 [Surgical therapy for hand infections Part 2]. 2005 Jul Due to its function, anatomy, and exposition to multiple pathogens, the hand is highly susceptible to infection. Most of these infections are post-traumatic. Isolates of pathogens from infected hands contain mainly Staphylococcus aureus and ss-haemolytic group A streptococci. But differential diagnosis also includes pyoderma gangrenosum, tumors of the hand, rheumatoid arthritis, and articular gout, as they may mimic hand infections. Infections of the hand can lead to massive tissue damage that needs to be reconstructed. The selection of methods depends on the localization and size of defects and includes primary closure, split- and full-thickness skin grafts, and more complex operations such as local, regional, and distant flaps.
15868631 Risk factors associated with rheumatic complaints: a WHO-ILAR COPCORD study in Shantou, So 2005 May OBJECTIVE: To validate the differences of the prevalence of rheumatic symptoms between the north and south part of China and to investigate the associated risk factors for rheumatic complaints in Shantou, China. METHODS: Four samples together comprising 10,638 people > or = 16 years of age were surveyed in 1987, 1992, 1995, and 1999. The protocol of the ILAR-China Collaborative Study or the WHO-ILAR COPCORD Core Questionnaire was implemented. Data on rheumatic symptoms that were part of these surveys were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints was increasing in the Shantou area during the recent decade (in 1987 11.6%, 1992 12.5%, 1995 16.0%, and 1999 19.8%). However, it was still lower than the rate in Beijing, China, in 1987 (40.0%). Rheumatic symptoms were more prevalent in women than in men, and were more frequently seen in the elderly than in young people. The most frequently involved site was the low back followed by the knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in the urban school-age population group. The prevalence of knee pain was significantly higher in people living in multi-story buildings without elevators compared with those living in single-story houses. The peak value of bone mineral density (BMD) in the Shantou population was 0.839 +/- 0.085 g/cm2 in men, and 0.723 +/- 0.064 g/cm2 in women, significantly higher than that reported in 13 other provinces and cities of China including Beijing. The sense of seeking a physician's care was higher in the population with a higher prevalence of rheumatic symptoms than that in the group with a lower prevalence of complaints. However, no significant difference was found in the rate of disability among the different population samples. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than in Beijing. Socioeconomic status, environmental differences (e.g., Shantou in the southern and Beijing in the northern part of China), sex, age, occupation, ergonomics, BMD, and awareness of seeking medical care might all be risk factors associated with the prevalence of rheumatic complaints.
15787743 The inhibitory effect of altered collagen II peptide on HLA-DRB1-restricted T-cell activat 2005 Mar It has been known that rheumatoid arthritis (RA)-associated antigenic peptides CII263-272 are coupled with human leucocyte antigen (HLA)-DRB1 and recognized by T-cell receptor (TCR), which in turn induced T-cell proliferation and pathogenesis of RA. Non-T-cell-stimulating type II collagen (CII) peptides might be generated by removing the amino acids responsible for TCR contact and keeping the HLA-DR-binding residues intact. In this study, a panel of altered CII peptides (APs) with consecutive or single substitutions of the TCR-contacting residues were synthesized. Through peptide binding and T-cell activation assays, we demonstrated that altered CII263-272 peptides with substitution of the TCR-contacting residues did not or barely induced T-cell activation; one of the best non-T-cell-stimulating peptide AP268-270 inhibited the binding of wild-type CII263-272 to HLA-DR1 and T-cell activation triggered by wild-type CII263-272 and HA306-318 in a dose-response manner. These data suggest that removal of the TCR-contacting residues of CII263-272 leads to HLA-DRB1 binding and low T-cell-stimulating peptides, which could potentially inhibit the T-cell response induced by HLA-DRB1-binding antigenic peptides.
16329093 Tissue trafficking patterns of effector memory CD4+ T cells in rheumatoid arthritis. 2005 Dec OBJECTIVE: Clonal populations of CD4+,CD28- T cells accumulating in rheumatoid arthritis functionally resemble end-differentiated, nondividing, short-lived effector memory cells that reside in peripheral tissues. We undertook this study to examine the tissue niche for CD4+,CD28- T cells and the signals regulating their survival and tissue homing patterns. METHODS: Chemokine receptor expression on CD4+,CD28- T cell clones and peripheral blood lymphocytes was assessed by multicolor cytometry. In vitro chemotaxis and transendothelial migration were examined in a Transwell system. In vivo tissue-homing patterns were established by adoptively transferring fluorescence-labeled T cell clones into SCID mice engrafted either with rheumatoid synovium or with human lymph nodes. RESULTS: CD4+,CD28- T cell clones adoptively transferred into human tissue-SCID mouse chimeras infiltrated rheumatoid synovium but preferentially homed to lymph nodes. Such T cells coexpressed the chemokine receptors CCR7, CCR5, and CXCR4 and migrated in response to both inflammatory chemokines (CCL5) and homing chemokines (CXCL12). T cell receptor crosslinking abrogated chemotactic responsiveness. In contrast, interleukin-12 stimulation induced the up-regulation of CCR5 and a shift in the in vivo homing pattern away from the lymph nodes toward the inflamed synovium. CONCLUSION: CD4+,CD28- T cells resemble both short-lived effector memory cells and long-lived central memory cells, and they find a niche both in inflamed synovium and in lymph nodes. Nonspecific cytokine stimulation, not antigen recognition, triggers the transition from the lymph node to the synovium. By maintaining CCR7 expression, these end-differentiated T cells can home to lymphoid organs, enhance their survival, support clonal expansion, and perpetuate autoreactivity.
17121619 Role of anti-tumour necrosis factor-alpha therapeutic agents in the emergence of infection 2006 Dec There is increasing interest concerning the possible impact of anti-tumour necrosis factor (TNF)-alpha therapeutic agents on the emergence of infections. However, these agents do not seem to increase the incidence of adverse infectious events significantly. Published observations concern mostly infections of the urinary and upper respiratory tracts that develop in the setting of co-morbidities, such as anterior or concomitant immunosuppressive treatment. Infliximab appears to increase the risk of tuberculosis, but this effect has not been observed with other anti-TNF-alpha agents. To better characterise the adverse infectious effects associated with these agents, physicians should be encouraged to notify the microbiological data relating to all cases.
16199245 Cardiovascular safety of lumiracoxib: a meta-analysis of all randomized controlled trials 2005 Aug BACKGROUND: The cardiovascular (CV) safety of non-steroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase-2 inhibitors has been the subject of considerable debate. OBJECTIVE: The objective of this study was to determine the risk of CV events with lumiracoxib by meta-analysis of all completed, randomized controlled trials (RCTs) of > or =1 week and up to 1 year in duration of patients with osteoarthritis and rheumatoid arthritis. METHODS: The Novartis Lumiracoxib Clinical Trial Database, which includes all clinical studies conducted to date with lumiracoxib, was reviewed. Data were extracted from RCTs of > or =1 week and up to 1 year in duration, the maximum study duration; 34,668 patients were included in standard and cumulative meta-analyses. Twenty-two RCTs of lumiracoxib 100 to 1200 mg daily were identified; 22,781 patients were included in 1-year trials. Mean age of the patients was 61.5 years and 74% were female. More than 50% of the patients in these studies had hypertension at baseline and 6% had diabetes. Parameters analyzed were the Antiplatelet Trialists' Collaboration (APTC) composite CV end point of myocardial infarction (MI), stroke (ischemic and hemorrhagic), and CV death; MI alone; and stroke alone. Twenty-one of the 22 RCTs have been published. RESULTS: For all 3 parameters, relative risk (RR) was calculated versus non-naproxen NSAIDs, naproxen, and placebo. The results were as follows: for the APTC end point versus non-naproxen NSAIDs: RR 0.83, 95% CI, 0.46-1.51; versus naproxen: RR 1.49, 95% CI, 0.94-2.36; versus placebo: RR 1.08, 95% CI, 0.41-2.86; for MI alone versus non-naproxen NSAIDs: RR 0.80, 95% CI, 0.28-2.25; versus naproxen: RR 1.69, 95% CI, 0.82-3.48; versus placebo: RR 1.27, 95% CI, 0.25-6.56; and for stroke alone versus non-naproxen NSAIDs: RR 0.91, 95% CI, 0.35-2.35; versus naproxen: RR 1.42, 95% CI, 0.70-2.91; versus placebo: RR 0.59, 95% CI, 0.13-2.74. Cumulative meta-analyses of lumiracoxib versus all comparators (placebo, diclofenac, ibuprofen, celecoxib, rofecoxib, and naproxen) did not find any significant differences in APTC, MI alone, or stroke alone. CONCLUSION: This meta-analysis of 34,668 patients receiving > or =1 week and up to 1 year of treatment found no evidence that lumiracoxib was associated with a significant increase in CV risk compared with naproxen, placebo, or all comparators (placebo, diclofenac, ibuprofen, celecoxib, rofecoxib, and naproxen).
16508938 Sphingosine 1-phosphate/sphingosine 1-phosphate receptor 1 signaling in rheumatoid synoviu 2006 Mar OBJECTIVE: Sphingosine 1-phosphate (S1P) is involved in various pathologic conditions and has been implicated as an important mediator of angiogenesis, inflammation, cancer, and autoimmunity. This study was undertaken to examine the role of S1P/S1P1 signaling in the pathogenesis of rheumatoid arthritis (RA). METHODS: We examined S1P1 messenger RNA (mRNA) and protein levels in RA synoviocytes and MH7A cells by reverse transcriptase-polymerase chain reaction and Western blotting. We also performed S1P1 immunohistochemistry analysis in synovial tissue from 28 RA patients and 18 osteoarthritis (OA) patients. We investigated the effects of S1P on proliferation by WST-1 assay, and its effects on tumor necrosis factor alpha (TNFalpha)- or interleukin-1beta (IL-1beta)-induced cyclooxygenase 2 (COX-2) expression and prostaglandin E2 (PGE2) production in RA synoviocytes and MH7A cells by Western blotting and enzyme-linked immunosorbent assay, respectively. Finally, we examined whether these effects of S1P were sensitive to pertussis toxin (PTX), an inhibitor of the Gi/Go proteins. RESULTS: S1P1 mRNA and protein were detected in RA synoviocytes and MH7A cells. S1P1 was more strongly expressed in synovial lining cells, vascular endothelial cells, and inflammatory mononuclear cells of RA synovium compared with OA synovium. S1P increased the proliferation of RA synoviocytes and MH7A cells. S1P alone significantly enhanced COX-2 expression and PGE2 production. Moreover, S1P enhanced expression of COX-2 and production of PGE2 induced by stimulation with TNFalpha or IL-1beta in RA synoviocytes and MH7A cells. These effects of S1P were inhibited by pretreatment with PTX. CONCLUSION: These findings suggest that S1P signaling via S1P receptors plays an important role in cell proliferation and inflammatory cytokine-induced COX-2 expression and PGE2 production by RA synoviocytes. Thus, regulation of S1P/S1P1 signaling may represent a novel therapeutic target in RA.
16634808 Imatinib mesylate inhibits proliferation of rheumatoid synovial fibroblast-like cells and 2006 May Receptors for platelet-derived growth factor (PDGF) are abundantly expressed on synovial fibroblast-like (SFL) cells from patients with rheumatoid arthritis (RA), and stimulation with PDGF enhances both the anchorage-dependent and -independent growth of RA-SFL cells. To elucidate the molecular mechanisms responsible for the excessive growth of RA-SFL cells and to seek a novel molecular-targeting therapy for RA, we examined the expression of adapter proteins and the effect of the specific inhibition of PDGF receptor activation by imatinib mesylate. Cultured SFL cells were used in the present study after 2-5 passages. The anchorage-dependent and -independent growth patterns of the SFL cells were evaluated using a tetrazolium-based assay and colony formation in 0.3% agar, respectively. Adapter proteins Gab1 and Gab2 were expressed in RA-SFL cells, and both proteins were rapidly (< 1 min) tyrosine-phosphorylated after the stimulation of RA-SFL cells with 10 ng/ml of PDGF and, to a lesser extent, after stimulation with 100 ng/ml of epidermal growth factor (EGF). The inhibition of PDGF receptor tyrosine kinase activation by 1 microM or less of imatinib mesylate specifically suppressed the PDGF-dependent, but not EGF-dependent, tyrosine phosphorylation of various proteins. Moreover, imatinib mesylate abolished both the anchorage-dependent and -independent proliferation of RA-SFL cells induced by PDGF stimulation. These results suggest that Gab adapter proteins are expressed and likely to be involved in the growth signalling of rheumatoid synovial cells and that imatinib mesylate, a key drug in the treatment of chronic myeloid leukaemia, may also be effective for the treatment of RA.
15930530 Epidemiology of total knee replacement in the United States Medicare population. 2005 Jun BACKGROUND: There are limited population-based data on the utilization and outcomes of total knee replacement. The aim of the present study was to describe the rates of primary and revision total knee replacement and selected outcomes in persons older than sixty-five years of age in the United States. METHODS: Using Medicare claims, we computed annual incidence rates of unilateral elective primary and revision total knee replacement among United States Medicare beneficiaries in the year 2000. Poisson regression was used to assess the relationships between demographic characteristics and the incidence rates of primary and revision knee replacement. Proportional hazards models were used to examine the relationships between the ninety-day rates of complications and demographic and clinical factors. RESULTS: The rate of primary knee replacement was lower in blacks than in whites and in those qualifying for Medicaid supplementation than in those with higher incomes. The complications observed during the ninety days following primary knee replacement included mortality (0.7%), readmission (0.9%), pulmonary embolus (0.8%), wound infection (0.4%), pneumonia (1.4%), and myocardial infarction (0.8%). The complications observed during the ninety days following revision knee replacement were mortality (1.1%), readmission (4.7%), pulmonary embolus (0.5%), wound infection (1.8%), pneumonia (1.4%), and myocardial infarction (1.0%). Blacks had higher rates of mortality, readmission, and wound infection after primary knee replacement than whites did. Patients who qualified for Medicaid supplementation had higher complication rates, particularly after primary knee replacement. CONCLUSIONS: Overall, the rates of postoperative complications during the ninety days following total knee replacement are low. In the United States, blacks and individuals with low income undergo total knee replacement less frequently and generally have higher rates of adverse outcomes following primary knee replacement.
15818703 Urinary type II collagen helical peptide (HELIX-II) as a new biochemical marker of cartila 2005 Apr OBJECTIVE: Type II collagen, which consists of a large helical domain and telopeptides at each end, is the most abundant protein of cartilage matrix. The aim of this study was to develop a biochemical marker reflecting the degradation of the helical region of type II collagen and to evaluate its clinical performance in patients with osteoarthritis (OA) and rheumatoid arthritis (RA). METHODS: We developed a competitive polyclonal antibody-based enzyme-linked immunosorbent assay (ELISA) using the 622-632 peptide derived from the sequence of the alpha1 chain of human type II collagen (HELIX-II) as immunogen and standard. We measured urinary levels of HELIX-II peptide and C-terminal crosslinking telopeptide of type II collagen (CTX-II) in 90 patients with knee OA (73% women; mean +/- SD age 63.0 +/- 8.0 years, mean +/- SD disease duration 6.1 +/- 6.8 years), 89 patients with early RA (disease duration /=0.5 units/year), with an odds ratio (OR) of 5.9 (95% confidence interval [95% CI] 2.0-17.2) after adjustment for serum C-reactive protein (CRP) levels and baseline joint damage. Patients with increased levels of both urinary HELIX-II and CTX-II had the highest risk of progression (OR 17.5 [95% CI 3.1-99]). CONCLUSION: The HELIX-II ELISA is specific for type II collagen degradation, has adequate technical performance, and can distinguish patients with knee OA or RA from healthy controls. Elevated HELIX-II levels are associated with increased risk of radiographic progression in RA independently of CRP levels, baseline joint damage, and urinary CTX-II levels. The HELIX-II ELISA should be useful for the clinical investigation of patients with arthritis and for identifying RA patients at higher risk of progression.
16511915 Simvastatin inhibits production of interleukin 6 (IL-6) and IL-8 and cell proliferation in 2006 Mar OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory disease in which the synovial environment is characterized by intense immunological activity. Evidence suggests that statins modulate immune functions and may have a beneficial effect on patients with RA. We investigated whether simvastatin could inhibit the expression of interleukin 6 (IL-6) and IL-8 and cell proliferation induced by tumor necrosis factor-alpha (TNF-alpha) in fibroblast-like synoviocytes (FLS) obtained from RA patients undergoing joint replacement therapy. METHODS: RA FLS were cultured with or without 0.05-10 microM simvastatin for 12 h. Cytokine mRNA expression and secretion levels were detected using real-time PCR and ELISA, respectively. Cell proliferation of FLS induced by TNF-alpha was determined by MTT assay. RESULTS: Real-time PCR analysis revealed that the levels of IL-6 and IL-8 mRNA expressed by FLS were reduced by simvastatin in a dose-dependent manner. Levels of IL-6 and IL-8 in FLS culture supernatants were decreased by simvastatin in a time-dependent and dose-dependent manner. MTT assay revealed that simvastatin could inhibit proliferation of FLS induced by TNF-alpha. These effects of simvastatin on IL-6 and IL-8 production and cell proliferation were reversed in the presence of mevalonic acid or geranylgeranyl-pyrophosphate, but not with farnesyl-pyrophosphate. CONCLUSION: Our results suggest that the beneficial effect of simvastatin in RA patients may involve inhibition of IL-6 and IL-8 production, as well as reduction of cell proliferation.
16239393 What does tumour necrosis factor excess do to the immune system long term? 2005 Nov Members of the tumour necrosis factor (TNF)/TNF-receptor (TNF-R) superfamily coordinate the immune response at multiple levels. For example, TNF, LTalpha, LTbeta and RANKL provide signals required for lymphoid neogenesis, CD27, OX-40, 4-1BB and CD30 deliver costimulatory signals to augment immune responses, while pro-apoptotic members such as TNF, CD95L and TRAIL may contribute to the termination of the response. Biological identity of individual family members has been revealed through studies of gain of function or gene deficient mutants. Most notable are the development of spontaneous inflammatory polyarthritis in human TNF-globin transgenic mice, the auto-inflammatory syndromes resulting from mutations in the 55-kDa TNF-R, and, in particular, the obligatory role for the RANKL/RANK axis in osteoclastogenesis and bone remodelling. A growing appreciation of the molecular basis of signalling pathways transduced by TNF-R has provided a framework for better understanding the biology of this expanding family. For while the rapid and robust activation of NF-kappaB and MAPK pathways is typical of acute TNF-R engagement, the molecular basis of sustained receptor signalling remains a mystery, in spite of its relevance to chronic inflammatory and immune responses. Focusing on T cells, this report describes some of the molecular footprints of sustained TNF-R engagement and illustrates how these may influence immune function. A common theme arising is that prolonged TNF stimulation alters signalling thresholds over time. The authors propose that one major outcome of long term exposure to TNF is a state of localised IL-2 deficiency at sites of inflammation. The implications of this deficiency are discussed.
15880344 Elevated CXCL16 expression by synovial macrophages recruits memory T cells into rheumatoid 2005 May OBJECTIVE: Directional migration of leukocytes is orchestrated by the regulated expression of chemokine receptors and their ligands. The receptor CXCR6 is abundantly expressed by Th1-polarized effector/memory lymphocytes accumulating at inflammatory sites. This study was undertaken to examine the presence of CXCR6+ T cells and of CXCL16, the only ligand for CXCR6, in the joints of patients with rheumatoid arthritis (RA). METHODS: Flow cytometry analysis of the expression of CXCR6 by peripheral blood and synovial fluid (SF) T cells. In addition, by performing conventional and real-time reverse transcriptase-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay, we determined the expression of CXCL16 and its protease ADAM-10 within synovium and by cultured macrophages. SF T cell migration was studied with the Transwell system. RESULTS: Accumulation of CXCR6+ T cells within RA SF coincided with highly elevated levels of CXCL16+ macrophages. In vitro studies revealed that monocytes started to express CXCL16 upon differentiation into macrophages, and that RA SF and tumor necrosis factor (TNF) enhanced CXCL16 expression. Moreover, RA patients responding to anti-TNF therapy showed a strongly decreased CXCL16 expression, whereas nonresponding patients did not. Interestingly, ADAM-10, a recently identified protease of CXCL16, was abundantly expressed by CXCL16+ macrophages in vitro and in RA in vivo, which resulted in increased levels of cleaved CXCL16 in RA SF relative to controls. Finally, CXCR6+ T cells from RA SF were attracted by CXCL16. CONCLUSION: These data provide evidence that enhanced production of CXCL16 in RA synovia leads to recruitment of CXCR6+ memory T cells, thereby contributing to the inflammatory cascade associated with RA pathology.
17054880 Cytokine-induced osteoclastic bone resorption in charcot arthropathy: an immunohistochemic 2006 Oct BACKGROUND: Charcot arthropathy is a chronic, progressive destructive process affecting bone architecture and joint alignment in people lacking protective sensation. The etiologic factors leading to progressive bone resorption have not been elucidated. The purpose of this study was to histologically examine surgical specimens with Charcot arthropathy for cell type and immunoreactivity of known cytokine mediators of bone resorption. METHODS: Tissue samples of 20 specimens with known Charcot arthropathy were stained for Hematoxylin and Eosin (H&E) to quantify cell type. Nine of the specimens were stained with interleukin-1 (IL-1) antibody, nine with tumor necrosis factor (TNF) alpha antibody, and nine with interleukin-6 (IL-6) antibody. Distribution of staining was graded as focal (less than 10% of cells), moderate (10% to 50% of cells), and diffuse (more than 50% of cells) by two independent investigators. Inflammatory cells in tissue sections of rheumatoid synovium served as a positive control. RESULTS: Osteoclasts were seen in excessive numbers lining the resorptive bone lacunae. There was a disproportionate increase in osteoclasts to osteoblasts in the Charcot-reactive bone. In each case, osteoclasts demonstrated immunoreactivity for IL-1, IL-6 and TNF-alpha with a grade of moderate or diffuse reactivity. CONCLUSION: The findings of excessive osteoclastic activity in the environment of cytokine mediators of bone resorption (IL-1, IL-6, and TNF-alpha) suggest enhanced bone resorption through the stimulation of osteoclastic progenitor cells as well as mature osteoclasts. Alteration in the synthesis, secretion, or activity of these important regulatory molecules through the use of pharmacologic agents may, in turn, alter bone remodeling and loss and lead to accelerated healing without collapse or malalignment.
17015691 RANTES modulates TLR4-induced cytokine secretion in human peripheral blood monocytes. 2006 Oct 15 Monocytes are the key regulators of joint inflammation and destruction in rheumatoid arthritis; hence, suppression of their recruitment into the joint may be therapeutically beneficial. Chemokines, including RANTES, are highly expressed in the joints of patient with rheumatoid arthritis, and they promote leukocyte trafficking into the synovial tissue. Because endogenous TLR4 ligands are expressed in the rheumatoid joint, the TLR4 ligand LPS was used to characterize the effects of RANTES on the TLR4-mediated induction of TNF-alpha and IL-6. Using peripheral blood (PB) monocytes, RANTES decreased LPS-induced IL-6 transcriptionally, whereas TNF-alpha was suppressed at the posttranscriptional level. RANTES signaled through p38 MAPK, and this signaling was further enhanced by LPS stimulation in PB monocytes, resulting in the earlier and increased secretion of IL-10. Inhibition of p38 by short-interfering RNA or a chemical inhibitor, as well as neutralization of IL-10, reversed the RANTES-mediated suppression of LPS-induced IL-6 and TNF-alpha. Further, when rheumatoid arthritis synovial fluid was added to PB monocytes, the neutralization of RANTES in fluid reduced the LPS-induced IL-10 and increased TNF-alpha. In conclusion, the results of this study suggest that RANTES down-regulates TLR4 ligation-induced IL-6 and TNF-alpha secretion by enhancing IL-10 production in PB monocytes. These observations suggest that the therapeutic neutralization of RANTES, in addition to decreasing the trafficking of leukocytes, may have a proinflammatory effect at the site of established chronic inflammation.