Browse

Search for: rheumatoid arthritis    methotrexate    autoimmune disease    biomarker    gene expression    GWAS    HLA genes    non-HLA genes   

ID PMID Title PublicationDate abstract
16996245 The outcome of pregnancy following pre-pregnancy or early pregnancy alendronate treatment. 2006 Nov In spite of a substantial increase in the use of bisphosphonates at child bearing age, very little is known regarding its use in pregnancy. We describe the outcome of 24 pregnancies after pre-pregnancy or early pregnancy alendronate therapy. Based on the pregnancy outcome it seems that alendronate does not impose a major teratogenic risk.
18840450 Ajulemic acid, a synthetic cannabinoid acid, induces an antiinflammatory profile of eicosa 2008 Nov 7 AIMS: To better understand mechanisms whereby Ajulemic acid (AjA), a synthetic antiinflammatory cannabinoid, promotes resolution of acute and chronic inflammation in animal models, we investigated its influence on cyclooxygenase 2 (COX2) expression and eicosanoid production in human fibroblast-like synovial cells (FLS). MAIN METHODS: FLS isolated from tissue obtained at joint replacement surgery or cultured from synovial fluid were treated for 60 min with AjA (10-30 microM), then stimulated with tumor necrosis factor alpha (TNFalpha). COX2 mRNA was measured by hybridization/colorimetric assay of whole cell lysates collected 4 h after stimulation. To determine effects on arachidonic acid release, FLS were incubated with (14)C-arachidonic acid for 20 h then treated with AjA (8-32 microM). Arachidonic acid release was measured by scintillation counting. Prostaglandins (PG) were measured by enzyme linked immunosorbent assay (ELISA) in cell supernatants collected 4 and 24 h after stimulation. KEY FINDINGS: AjA increased the steady state levels of COX2 mRNA in and arachidonic acid release from FLS. Treatment of FLS with AjA increased 15-deoxy-delta(12,14)-PGJ(2) (15d-PGJ(2)) production in a concentration dependent manner, but did not affect PGE(2) production significantly. SIGNIFICANCE: The capacity of AjA to increase selectively and markedly 15d-PGJ(2), an eicosanoid which facilitates resolution of inflammation, suggests that AjA may have value as a therapeutic agent for the treatment of rheumatoid arthritis (RA) and other diseases characterized by acute and chronic inflammation.
18203762 The synovitis of "non-inflammatory" orthopaedic arthropathies: a quantitative histological 2008 Aug OBJECTIVE: To quantify inflammatory changes in synovial membranes from orthopaedic "non-inflammatory" arthropathies (Orth. A). METHODS: Synovial membranes from patients with femur fracture, avascular necrosis of the femur, plica syndrome, and meniscus and/or ligament injury (n = 23); rheumatoid arthritis (n = 28); osteoarthritis (OA; n = 25); and from normal controls (n = 10) were assessed by light microscopy, a histological synovitis score, immunostaining for CD3, CD20, CD38, CD68, Ki-67 and von Willebrand factor, and with an immunohistochemical inflammation score. RESULTS: Orth. A histology varied between normal and markedly inflamed. Predominant abnormalities were mild lining hyperplasia, scattered inflammatory cells and small perivascular infiltrates. The synovitis score classified Orth. A as "mild synovitis". Inflammatory cells occurred frequently: CD68+ cells in 100% of Orth. A specimens; CD3+, 91%; CD38+, 70%; and CD20+, 39%. Orth. A had 36% greater lining thickness (p = 0.04), 40% higher vascular density (p = 0.009) and 51.3-fold higher CD38+ cell density (p = 0.02) than normal controls; and 60% fewer subintimal Ki-67+ cells (p = 0.003), 42% fewer CD68+ lining cells (p<0.01) and 40% fewer subintimal CD68+ cells (p<0.01) than OA. The immunohistochemical inflammation score was 2.2-fold higher in Orth. A than in controls (p = 0.048) and similar to OA, with three Orth. A specimens showing marked inflammation. CONCLUSIONS: Synovial membranes from "non-inflammatory" arthropathies featured neovascularisation and inflammation intermediate between normal and OA synovium. These results expand previous findings that mechanical joint injury may lead to a mild-to-moderate synovitis.
18612206 Power of genetic association studies in the presence of linkage disequilibrium and allelic 2008 OBJECTIVES: The calculation of the power and sample size required for association studies is essential, particularly for follow-up of genome-wide association studies, where much genotyping is required to replicate the original finding and identify the true disease susceptibility mutation. METHODS: In this paper, we derive equations for estimation of sample sizes for the transmission disequilibrium test (TDT) and for case-control studies, in the presence of allelic heterogeneity and indirect association - where the genotyped tagging SNP is in linkage disequilibrium (LD) with the true mutation. Using data from NOD2 and PTPN22, we show that the true sample sizes required to detect association may be incorrect when calculated under the assumption of a single mutation and complete LD with the genotyped marker. RESULTS: The true sample sizes may be lower when allelic heterogeneity acts in a recessive model across mutations, or increased when mutations lie on different alleles of a common tagging SNP. CONCLUSION: Calculating power and sample size under a range of realistic models of LD and allelic heterogeneity is essential to ensure that association studies have sufficient power to detect mutations.
18503406 Management of chronic nonmalignant pain with nonsteroidal antiinflammatory drugs. Joint op 2008 Jun Chronic nonmalignant pain is a major burden on the health care system in the United States. Frequently, nonsteroidal antiinflammatory drugs (NSAIDs) are used to assist in the management of various chronic pain syndromes. Although evidence is accumulating on the potential toxicities associated with NSAIDs, clear recommendations are lacking to guide the appropriate use of these drugs. Equivocal data, especially with respect to cardiovascular risk, further confuse a clear treatment pathway when assessing pharmacotherapy. Originally, cyclooxygenase selectivity appeared to be a determining factor in choosing an agent because of the presumed lack of effect on the cardiovascular and gastrointestinal renal systems. This theory, however, was recently dispelled. To provide guidance on the selection of an NSAID for various chronic pain syndromes, members of the Ambulatory Care, Cardiology, and Pain and Palliative Care Practice and Research Networks of the American College of Clinical Pharmacy evaluated evidence-based use of NSAIDs for frequently encountered pain syndromes, with special focus on the adverse effects of this class of agents.
17035286 A qualitative study to identify factors influencing COXIB prescribed by family physicians 2006 Dec INTRODUCTION: Cyclo-oxygenase-2 inhibiting (COXIB) anti-inflammatories have been the drug class prescribed for a large number of cases of musculoskeletal (MSK) disorders in Canada over the past 5 years. The Alberta Improvements for MSK Disorders (AIMS) initiative sought to better understand the COXIB prescribing situation by funding several studies. The objective of this qualitative study was to determine the factors underlying primary care physicians' medication prescribing behaviour during an office visit for an MSK disorder, with particular emphasis on the prescribing of COXIBs. METHODS: The target respondents were Alberta primary care physicians chosen from a stratified random sample to meet a wide range of characteristics. Individual, semi-structured interviews were used to assess decision pathways in four real cases chosen by the physician. A total of 19 interviews were conducted and analysed using an analytic inductive approach. RESULTS: Factors judged as being important to decision pathways in relation to COXIB prescribing for MSK disease included safety, patient characteristics, affordability to patients, availability of samples, drug company marketing practices, habit formation, time contstraints, previous clinical experience of doctors and/or patient with certain drugs and doctors' perception of absolute versus relative risk. Interpretation. Most physicians preferentially prescribed COXIBs subsequent to a complicated, multifactorial, but essentially patient-centred, decision-making process.
16456878 Achilles tendon rupture and its association with fluoroquinolone antibiotics and other pot 2006 Nov BACKGROUND: Case reports and observational studies have implicated fluoroquinolone antibiotic exposure as a risk factor for Achilles tendon rupture (ATR), an uncommon condition for which there are few formal studies. We sought to quantify the strength of association between exposure to fluoroquinolone antibiotics and the occurrence of ATR, accounting for other risk factors. METHODS: This was a case-control study nested within a health insurer cohort. Cases of ATR were identified and confirmed using patterns of health insurance claims that were validated through sampled medical record review. Information on risk factors, including fluoroquinolone exposure, came from health insurance claims. RESULTS: There were 947 cases of ATR and 18 940 controls. A dispensing of a fluoroquinolone antibiotic in the past 6 months was more common among ATR cases than controls, although not significantly so (odds ratio (OR) = 1.2; 95% confidence interval (CI) = 0.9-1.7), and exposure to a higher cumulative fluoroquinolone dose was more strongly associated (OR = 1.5, 95%CI = 1.0-2.3). Other risk factors for ATR were trauma (OR = 17.2, 95%CI = 14.0-20.2), male sex (OR = 3.0, 95%CI = 2.6-3.5), injected corticosteroid administration (OR = 2.2, 95%CI = 1.6-2.9), obesity (OR = 2.0, 95%CI = 1.2-3.1), rheumatoid arthritis (OR = 1.9, 95%CI = 1.0-3.7), skin or soft tissue infections (OR = 1.5, 95%CI = 0.9-2.3), oral corticosteroids (OR = 1.4, 95%CI = 1.0-1.8), and non-fluoroquinolone antibiotics (OR = 1.2, 95%CI = 1.1-1.5). CONCLUSIONS: The elevation in ATR risk associated with fluoroquinolones was similar in magnitude to that associated with oral corticosteroids or non-fluoroquinolone antibiotics. Trauma and male sex were more strongly associated with ATR, as were obesity and injected corticosteroids.
18625622 IL-6 receptor inhibition with tocilizumab improves treatment outcomes in patients with rhe 2008 Nov OBJECTIVES: The phase III RADIATE study examined the efficacy and safety of tocilizumab, an anti-IL-6 receptor monoclonal antibody in patients with rheumatoid arthritis (RA) refractory to tumour necrosis factor (TNF) antagonist therapy. METHODS: 499 patients with inadequate response to one or more TNF antagonists were randomly assigned to receive 8 mg/kg or 4 mg/kg tocilizumab or placebo (control) intravenously every 4 weeks with stable methotrexate for 24 weeks. ACR20 responses, secondary efficacy and safety endpoints were assessed. RESULTS: ACR20 was achieved at 24 weeks by 50.0%, 30.4% and 10.1% of patients in the 8 mg/kg, 4 mg/kg and control groups, respectively (less than p<0.001 both tocilizumab groups versus control). At week 4 more patients achieved ACR20 in 8 mg/kg tocilizumab versus controls (less than p = 0.001). Patients responded regardless of most recently failed anti-TNF or the number of failed treatments. DAS28 remission (DAS28 <2.6) rates at week 24 were clearly dose related, being achieved by 30.1%, 7.6% and 1.6% of 8 mg/kg, 4 mg/kg and control groups (less than p = 0.001 for 8 mg/kg and p = 0.053 for 4 mg/kg versus control). Most adverse events were mild or moderate with overall incidences of 84.0%, 87.1% and 80.6%, respectively. The most common adverse events with higher incidence in tocilizumab groups were infections, gastrointestinal symptoms, rash and headache. The incidence of serious adverse events was higher in controls (11.3%) than in the 8 mg/kg (6.3%) and 4 mg/kg (7.4%) groups. CONCLUSION: Tocilizumab plus methotrexate is effective in achieving rapid and sustained improvements in signs and symptoms of RA in patients with inadequate response to TNF antagonists and has a manageable safety profile. TRIAL REGISTRATION NUMBER: NCT00106522.
17644543 Cytokines, autoantibodies and viral antibodies in premorbid and postdiagnostic sera from p 2008 Jun OBJECTIVE: To assess the timing of changes in cytokines, cytokine-related markers, autoantibodies and viral antibodies in the pathogenesis of rheumatoid arthritis (RA). METHODS: Case-control study nested in a prospective cohort of 31 330 blood donors in Oslo, Norway. Forty-nine donors developed RA up to 23 years after their most recent blood donation. Stored sera from these donors (case sera) and a sex- and age-matched sample of 245 healthy donors (control sera), and postdiagnostic sera from 33 of the 49 RA cases, were analysed for a panel of cytokines and cytokine-related markers, autoantibodies and antibodies against Epstein-Barr virus and parvovirus B19. RESULTS: Cytokines and cytokine-related markers were generally negative in case sera from >5 years before the diagnosis of RA. In the 5-year interval immediately before the diagnosis of RA, more case than control sera were positive (odds ratios >2) for interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist, IL-4, IL-10, tumour necrosis factor-alpha and soluble tumour necrosis factor receptor I. In postdiagnostic sera, however, 11 of 16 examined cytokines and cytokine-related markers were statistically significantly elevated compared with control sera. Seropositivity for IgG antibodies against cyclic citrullinated peptides and for IgM and IgA rheumatoid factors were seen in case sera from up to 18 years before the diagnosis of RA. IgG antibodies against Epstein-Barr virus and parvovirus B19 did not differ significantly between case and control sera. CONCLUSIONS: Cytokines and cytokine-related markers appear to be upregulated rather late in RA pathogenesis. In contrast, IgM rheumatoid factor and IgG anti-cyclic citrullinated peptide autoantibodies may precede the diagnosis of RA by up to two decades.
16319097 VIP down-regulates TLR4 expression and TLR4-mediated chemokine production in human rheumat 2006 May OBJECTIVES: Vasoactive intestinal peptide (VIP) has demonstrated therapeutic effects in arthritis by inhibiting both innate and acquired immune responses. We investigated the potential effects of VIP in the regulation of Toll-like receptor (TLR) expression and function in synovial fibroblasts from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: Cultured fibroblast-like synoviocytes (FLS) were obtained from patients with RA and OA. The effects of VIP on basal or TNF-alpha or lipopolysaccharide (LPS)-induced TLR2, TLR4 and MyD88 expression and its effects on TLR4-mediated CCL2 and CXCL8 chemokine production were studied by reverse transcription-polymerase chain reaction, western blotting and enzyme-linked immunosorbent assay. RESULTS: TLR2, TLR4 and MyD88 mRNA expression was increased in RA FLS compared with OA FLS. The largest increase was observed for TLR4 and there was also overexpression at the protein level in RA FLS. TLR4 and MyD88 mRNA and proteins were induced by LPS and TNF-alpha in RA FLS. VIP down-regulated the induced but not the constitutive expression of TLR4 and MyD88 in RA FLS. VIP treatment decreased CCL2 and CXCL8 chemokine production in response to TLR4 activation with LPS in RA FLS. CONCLUSIONS: We demonstrate that VIP down-regulates LPS and TNF-alpha activation of TLR4 expression and the TLR4 functional response in terms of proinflammatory chemokine production. These studies suggest that the pleiotropic anti-inflammatory actions of VIP involve inhibitory effects on TLR4 expression and signalling.
17555825 Therapeutic application of anti-arthritis, pain-releasing, and anti-cancer effects of bee 2007 Aug Bee venom (BV) therapy (BVT), the therapeutic application of BV, has been used in traditional medicine to treat diseases, such as arthritis, rheumatism, pain, cancerous tumors, and skin diseases. BV contains a variety of peptides, including melittin, apamin, adolapin, the mast-cell-degranulating (MCD) peptide, enzymes (i.e., phospholipase [PL] A(2)), biologically active amines (i.e., histamine and epinephrine), and nonpeptide components which have a variety of pharmaceutical properties. BV has been reported to have anti-arthritis effects in several arthritis models. Melittin, a major peptide component of BV, has anti-inflammatory and anti-arthritis properties, and its inhibitory activity on nuclear factor kappaB (NF-kappaB) may be essential for the effects of BV. The anti-nociceptive effects of BV have also been demonstrated in thermal, visceral, and inflammatory pain models. Apcupoint stimulation (apipuncture) therapy into subcutaneous region may be important in the BV-induced anti-nociceptive effects. Multiple mechanisms, such as activation of the central and spinal opiod receptor, and alpha(2)-adrenergic activity, as well as activation of the descending serotonergic pathway have been suggested. The inhibition of c-Fos expression in the spinal cord by BV apipuncture in several nociceptive models is also reported to be a possible mechanism. BV also has anti-cancer activity. The cell cytotoxic effects through the activation of PLA(2) by melittin have been suggested to be the critical mechanism for the anti-cancer activity of BV. The conjugation of cell lytic peptide (melittin) with hormone receptors and gene therapy carrying melittin can be useful as a novel targeted therapy for some types of cancer, such as prostate and breast cancer.
17963656 Applicability of the mini-subvastus total knee arthroplasty technique: an analysis of 725 2007 Fall Recent total knee arthroplasty (TKA) studies suggest a more rapid functional recovery with minimally invasive surgical (MIS) techniques. These studies often fail to disclose the percentage of primary TKA that underwent the MIS technique, raising the concern that positive clinical outcomes are a result of patient selection. This study evaluates the applicability of the mini-subvastus technique in one surgeon's consecutive primary TKA patients. The applicability was determined utilizing a computer record review to determine the percentage of primary TKA patients in which the surgeon utilized a MIS surgical technique. The mini-subvastus approach was applied to 99% of 732 consecutive primary TKA. There was no patient selection based on age or weight. Traditional TKA, utilizing a medial parapatellar arthrotomy, was more likely to be performed on patients with a diagnosis of traumatic arthritis and in knees that required stems or augments. Preoperative tibiofemoral angle and mean knee deformity were not predictors of which procedure would be utilized. Despite employing this new surgical approach in nearly all primary TKAs, there was no increase in the complication rate. This high applicability rate with the mini-subvastus technique obviates concerns that the positive clinical outcomes in these patients are a result of patient selection.
18678578 Local delivery of a recombinant adenoassociated vector containing a tumour necrosis factor 2009 Aug OBJECTIVE: To examine the safety and tolerability of a single intra-articular injection of rAAV2-TNFR:Fc, an adenoassociated virus serotype 2 vector containing the cDNA for the human tumour necrosis factor-immunoglobulin Fc fusion gene (tgAAC94), in subjects with inflammatory arthritis. METHODS: In a double-blind, placebo-controlled, phase 1, dose-escalation study, 15 subjects with inflammatory arthritis (14 with rheumatoid arthritis and 1 with ankylosing spondylitis) not receiving tumour necrosis factor alpha (TNFalpha) inhibitors with persistent moderate (grade 2) or severe (grade 3) swelling in a target joint due to inflammatory arthritis received a single intra-articular injection of rAAV2-TNFR:Fc at 1 x 10(10) (n = 5) or 1 x 10(11) (n = 6) DNase resistant particles per ml joint volume or placebo (n = 4) into a knee (n = 14) or ankle (n = 1). Safety was assessed through adverse event monitoring. As a secondary objective, changes in injected joint tenderness and swelling scores, each measured on a four-point scale, were evaluated. RESULTS: Intra-articular injections of rAAV2-TNFR:Fc were well tolerated with no major safety issues. One event, mild knee pruritus, was considered probably related. Synovial fluid TNFR:Fc protein was not detected (nor expected) at the doses used. At 12 weeks after injection, a two-point decrease in swelling was noted in 2/11 and 2/4 subjects injected with rAAV2-TNFR:Fc and placebo, respectively. CONCLUSION: A single dose of intra-articular rAAV2-TNFR:Fc appears to be safe and well tolerated in subjects without concurrent systemic TNFalpha antagonist use. It is thus feasible to proceed with larger trials to further test the safety and efficacy of local TNFR:Fc gene transfer as a therapeutic modality for patients with inflammatory arthritis.
17158212 Pregnancy in rheumatology patients exposed to anti-tumour necrosis factor (TNF)-alpha ther 2007 Apr OBJECTIVES: Anti-tumour necrosis factor (TNF)-alpha therapies are considered category B drugs for pregnancy. Although sometimes prescribed to women of reproductive age, data in humans are limited with regard to safety for a developing fetus. The objectives of the present article are to report experience of anti-TNF-alpha use in pregnancy, and review the international literature. METHODS: Since 1999 the present authors have used anti-TNF-alpha (infliximab, etanercept, adalimumab) to treat patients with various chronic rheumatic conditions. All patients were prospectively followed during their treatment time and data were systematically collected. RESULTS: In a group of 442 patients treated with anti-TNF, three women with RA unexpectedly became pregnant One treated with etanercept chose a therapeutic termination at two and a half months, despite of any ultrasound anomaly, and satisfactory fetal growth. The other two patients (one with adalimumab exposure and one with etanercept exposure) delivered healthy infants. The following perinatal complications were observed: prematurity, neonatal jaundice, neonatal urinary Escherichia coli infection and adrenal congenital hyperplasia of probable hereditary origin. CONCLUSIONS: To date, there is no evidence that TNF-alpha antagonists are associated with embryo toxicity, teratogenicity or increased pregnancy loss. However, caution should be taken when anti-TNF agents are used during pregnancy, as human experience is still extremely limited, particularly in patients with rheumatic diseases among whom there are several alarming reports. The potential risk should be balanced against the known risks associated with DMARDs and steroid therapy. Large registries will be necessary before firm conclusions can be drawn.
18270228 Use of bisphosphonates and dual-energy X-ray absorptiometry scans in the prevention and tr 2008 Apr BACKGROUND: Patients treated with steroids are at risk of glucocorticoid-induced osteoporosis. Appropriate investigations and therapeutic agents can decrease rate of bone loss and fracture. AIM: To review adherence to current UK guidelines for the prevention of glucocorticoid-induced osteoporosis in rheumatology outpatient clinics. DESIGN: Retrospective case note review. METHODS: The management of patients taking glucocorticoids who attended outpatient rheumatology clinics at a Teaching Hospital NHS Trust over a 4-week period was reviewed against current UK recommendations for prevention and treatment of osteoporosis (Bone and Tooth Society, National Osteoporosis Society, Royal College of Physicians. Glucocorticoid-induced osteoporosis: guidelines for prevention and treatment. London: Royal College Physicians, 2002). RESULTS: Over the study period, 519 patients attended rheumatology outpatient clinics, amongst whom 104 were current glucocorticoid users. Most patients had been taking oral steroids for over 12 months (n = 79, 76%). The majority had also received steroids by at least one other route (n = 67, 64.4%). According to the guidelines, 51 patients, at relatively low risk of osteoporosis (<65 years, no previous fragility fracture) should have been referred for bone density assessment; of these, 27 (53%) had received a DEXA scan. In total, 58 subjects fulfilled criteria for bisphosphonates (>65 years, fragility fracture, T-score <-1.5) and, of these, 51 (87.9%) were appropriately treated. In 21 cases, a DEXA scan had been performed when guidelines recommended that treatment could commence without further assessment. DISCUSSION: The findings indicate a high level of awareness of glucocorticoid-induced osteoporosis amongst UK rheumatologists. Most patients identified to be at high risk of bone loss were offered treatment. Although encouraging, current practice could potentially be improved, particularly through more targeted use of DEXA scanning.
16912945 Antirheumatic drugs and the risk of tuberculosis. 2006 Sep 15 BACKGROUND: We aimed to quantify the rate of Mycobacterium tuberculosis disease (TB) among a cohort of patients with rheumatoid arthritis (RA) and to assess whether the independent use of disease-modifying antirheumatic drugs (DMARDs) is associated with the risk of developing TB. METHODS: The study was performed using the PharMetrics Patient-Centric database (PharMetrics). The cohort consisted of all subjects with > or =1 occurrence of a diagnosis of RA during an inpatient or outpatient visit during the period of September 1998 through December 2003. Conditional logistic regression was used in a nested case-control analysis to estimate the rate ratio (RR) of TB with any use of biological or traditional DMARDs during the year before the index date. We also assessed the interaction between DMARDs and the current use of corticosteroids. RESULTS: The cohort consisted of 112,300 patients with RA. A total of 386 cases of TB were identified, which resulted in an overall rate of 2.19 cases per 1000 person-years. The adjusted RR of TB for biological DMARD use is 1.5 (95% CI, 1.1-1.9). Use of traditional DMARDs was also independently associated with TB (RR, 1.2; 95% CI, 1.0-1.5). RRs of developing TB disease with the use of biological or traditional DMARD were lower among current users of corticosteroids than among noncurrent users of corticosteroids. CONCLUSION: We found that the use of biological and traditional DMARDs is associated with an increased risk of developing TB in patients with RA, mainly among noncurrent users of corticosteroids.
18635595 Dissecting the contribution of innate and antigen-specific pathways to the breach of self- 2009 Jun BACKGROUND: The relative roles of innate immunity and antigen-specific T cells in rheumatoid arthritis remain controversial. Previous studies demonstrated that T-helper type 1 cells of irrelevant antigen specificity (ovalbumin) induced a transient arthritis in BALB/c mice, which recapitulates many of the pre-articular and articular features of human disease and is associated with the emergence of autoreactive T and B-cell responses to joint-specific antigens. However, the mechanisms underlying this phenomenon were unclear. OBJECTIVES: The aim of this study was to dissect the relative contribution of innate and heterologous antigen-specific pathways to the breach of self-tolerance and pathology observed in this model and how this may result from modified T and B-cell interactions. METHODS: To address this issue, experimental arthritis was elicited either by a non-specific inflammatory stimulus alone, by activation of T cells of an irrelevant specificity or a combination of both. RESULTS: The non-specific inflammatory response generated by lipopolysaccharide led to articular inflammation and cartilage erosion, but did not break tolerance to joint-specific antigens. In contrast, local activation of T cells of an irrelevant specificity produced a similar pathological picture but, in addition, induced T-cell responses to unrelated joint-specific antigens with associated activation of autoreactive B cells. These effects could be further potentiated by the addition of lipopolysaccharide. CONCLUSION: These data demonstrate that non-specific inflammation alone is insufficient to breach self-tolerance. In contrast, T cells of an irrelevant specificity, when triggered locally in an antigen-specific manner, can breach self-tolerance leading to arthritis and autoantibody production, which can then be amplified in a non-specific manner.
18465883 Towards absolute quantification of therapeutic monoclonal antibody in serum by LC-MS/MS us 2008 Jun 1 Although LC-MS methods are increasingly used for the absolute quantification of proteins, the lack of appropriate internal standard (IS) hinders the development of rapid and standardized analytical methods for both in vitro and in vivo studies. Here, we have developed a novel method for the absolute quantification of a therapeutic protein, which is monoclonal antibody (mAb). The method combines liquid chromatography tandem mass spectrometry (LC-MS/MS) and protein cleavage isotope dilution mass spectrometry with the isotope-labeled mAb as IS. The latter was identical to the analyzed mAb with the exception that each threonine contains four (13)C atoms and one (15)N atom. Serum samples were spiked with IS prior to the overnight trypsin digestion and subsequent sample cleanup. Sample extracts were analyzed on a C18 ACE column (150 mm x 4.6 mm) using an LC gradient time of 11 min. Endogenous mAb concentrations were determined by calculating the peak height ratio of its signature peptide to the corresponding isotope-labeled peptide. The linear dynamic range was established between 5.00 and 1000 microg/mL mAb with accuracy and precision within +/-15% at all concentrations and below +/-20% at the LLOQ (lower limit of quantification). The overall method recovery in terms of mAb was 14%. The losses due to sample preparation (digestion and purification) were 72% from which about 32% was due to the first step of the method, the sample digestion. This huge loss during sample preparation strongly emphasizes the necessity to employ an IS right from the beginning. Our method was successfully applied to the mAb quantification in marmoset serum study samples, and the precision obtained on duplicate samples was, in most cases, below 20%. The comparison with enzyme-linked immunosorbent assay (ELISA) showed higher exposure in terms of AUC and Cmax with the LC-MS/MS method. Possible reasons for this discrepancy are discussed in this study. The results of this study indicate that our LC-MS/MS method is a simple, rapid, and precise approach for the therapeutic mAb quantification to support preclinical and clinical studies.
16385498 Anti-tumor necrosis factor therapy increases synovial osteoprotegerin expression in rheuma 2006 Jan OBJECTIVE: Treatment of rheumatoid arthritis (RA) with tumor necrosis factor (TNF)-blocking agents, including etanercept and infliximab, has resulted in reductions in the radiographic progression of RA. However, the exact mechanism by which this protection occurs has not been determined. In order to add to such knowledge, we investigated the effect of anti-TNF therapy on the expression of osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL) in synovial tissue. METHODS: The expression of OPG and RANKL in synovial biopsy specimens was evaluated by immunohistochemistry. Serial synovial biopsy specimens were obtained from 18 patients with RA, before and after treatment with etanercept (9 patients) or infliximab (9 patients). Biopsy specimens were evaluated by double-blind semiquantitative analysis and image analysis. The in vitro effect of TNF antagonists on the RANKL/OPG expression in osteoblasts and endothelial cells was evaluated by Western blotting. Statistical analysis was performed using Wilcoxon's signed rank test, followed by the Bonferroni correction for multiple comparisons of paired samples. The results of in vitro experiments were evaluated by one-way analysis of variance, with Tukey's post hoc test. RESULTS: Treatment with both infliximab and etanercept increased the expression of OPG in synovial tissue. After 8 weeks of treatment, neither infliximab nor etanercept influenced RANKL expression. In both groups of patients, the RANKL:OPG ratio decreased following therapy. In vitro, both of the TNF antagonists mimicked the in vivo effect, inducing a decrease in the RANKL:OPG ratio in TNF-primed osteoblasts and endothelial cells. CONCLUSION: Therapy with TNF antagonists in RA modulates the OPG/RANKL system, a potential mechanism that could explain the retardation of radiographic damage observed following anti-TNF therapy.
17882114 Current understanding of osteoporosis according to the position of the World Health Organi 2007 Jul The study documents a general change of position on osteoporosis (definition, diagnosis, aim of treatment). Taking into consideration a multifactorial nature of bone fragility in osteoporosis we do not diagnose "osteoporosis" but a total, individual 10-year fracture risk (AR-10) on the basis of independent and self-sufficient risk factors. These are: advanced age, prior fragility fracture, parental history of proximal femur fracture, low BMI, low bone mass, glicocortycosteroids treatment, rheumatoid arthritis, smoking, overuse of alcohol. The treatment should be implemented in persons burdened with a fracture risk higher than a population risk. The intervention threshold is a result of an agreement and a result of work of various working groups of experts. According to Johnell AR-10 below 8% does not require a therapeutical intervention; above 14% justifies the treatment independently of BMD measurement. AR-10 between 8% and 14% is an indication for BMD measurement precising fracture risk. The aim of the treatment is to decrease fracture risk. It combines a limitation of fracture risk factors effects including fall prevention and improvement of bone quality with applying pharmacotherapy. This study highlights that a bone mineral measurement, so far accepted as a criteria for diagnosis of osteoporosis or its exclusion should not be made in aim of diagnosis but to evaluate an absolute fracture risk. Spinal X-rays are performed in aim to diagnose vertebral fractures, which mean a multiple increase of risk of further fractures. The principles of low bone mass differential diagnosis and current possibility of pharmacological treatment are also described. Guidelines for fall avoidance in fracture prevention are described.