Robert Dinser

Synovial fibroblasts spread rheumatoid arthritis to unaffected joints

Active rheumatoid arthritis originates from few joints but subsequently affects the majority of joints. Thus far, the pathways of the progression of the disease are largely unknown. As rheumatoid arthritis synovial fibroblasts (RASFs) which can be found in RA synovium are key players in joint destruction and are able to migrate in vitro, we evaluated the potential of RASFs to spread the disease in vivo. To simulate the primary joint of origin, we implanted healthy human cartilage together with RASFs subcutaneously into severe combined immunodeficient (SCID) mice. At the contralateral flank, we implanted healthy cartilage without cells. RASFs showed an active movement to the naive cartilage via the vasculature independent of the site of application of RASFs into the SCID mouse, leading to a marked destruction of the target cartilage. These findings support the hypothesis that the characteristic clinical phenomenon of destructive arthritis spreading between joints is mediated, at least in part, by the transmigration of activated RASFs.

Update on the profile of the EUSTAR cohort: an analysis of the EULAR Scleroderma Trials and Research group database

Objectives Systemic sclerosis (SSc) is a rare disease requiring multicentre collaboration to reveal comprehensive details of disease-related causes for morbidity and mortality. Methods The European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) group initiated a database to prospectively gather key data of patients with SSc using a minimal essential dataset that was reorganised in 2008 introducing new items. Baseline visit data of patients who were registered between 2004 and 2011 were analysed using descriptive statistics. Results In June 2011, 7655 patients (2838 with diffuse cutaneous (dc) and 4481 with limited cutaneous (lc) SSc who fulfilled the American College of Rheumatology diagnostic criteria had been registered in 174 centres, mainly European. The most prominent hallmarks of disease were Raynauds phenomenon (96.3%), antinuclear antibodies (93.4%) and a typical capillaroscopic pattern (90.9%). Scleroderma was more common on fingers and hands than on any other part of the skin. Proton pump inhibitors (65.2%), calcium channel blockers (52.7%), and corticosteroids (45.3%) were most often prescribed. Among the immunosuppressant agents, cyclophosphamide was used more often in dcSSc than in lcSSc. Conclusions The EUSTAR database provides an abundance of information on the true clinical face of SSc that will be helpful in improving the classification of SSc and its subsets and for developing more specific therapeutic recommendations.

Fibroblast activation protein is expressed by rheumatoid myofibroblast-like synoviocytes

Fibroblast activation protein (FAP), as described so far, is a type II cell surface serine protease expressed by fibroblastic cells in areas of active tissue remodelling such as tumour stroma or healing wounds. We investigated the expression of FAP by fibroblast-like synoviocytes (FLSs) and compared the synovial expression pattern in rheumatoid arthritis (RA) and osteoarthritis (OA) patients. Synovial tissue from diseased joints of 20 patients, 10 patients with refractory RA and 10 patients with end-stage OA, was collected during routine surgery. As a result, FLSs from intensively inflamed synovial tissues of refractory RA expressed FAP at high density. Moreover, FAP expression was co-localised with matrix metalloproteinases (MMP-1 and MMP-13) and CD44 splice variants v3 and v7/8 known to play a major role in the concert of extracellular matrix degradation. The pattern of signals appeared to constitute a characteristic feature of FLSs involved in rheumatoid arthritic joint-destructive processes. These FAP-expressing FLSs with a phenotype of smooth muscle actin-positive myofibroblasts were located in the lining layer of the synovium and differ distinctly from Thy-1-expressing and non-proliferating fibroblasts of the articular matrix. The intensity of FAP-specific staining in synovial tissue from patients with RA was found to be different when compared with end-stage OA. Because expression of FAP by RA FLSs has not been described before, the findings of this study highlight a novel element in cartilage and bone destruction of arthritic joints. Moreover, the specific expression pattern qualifies FAP as a therapeutic target for inhibiting the destructive potential of fibroblast-like synovial cells.

Evaluation of latent tuberculosis infection in patients with inflammatory arthropathies before treatment with TNF-α blocking drugs using a novel flow-cytometric interferon-γ release assay

OBJECTIVE To compare the efficacy of the conventional skin test and a novel flow cytometric whole blood assay in the diagnosis of latent tuberculosis infection (LTBI) in patients with rheumatological diseases evaluated for treatment with TNF-alpha-blocking agents. METHODS Prospective study of 97 consecutively enrolled patients, who were assessed for the presence of LTBI through clinical history, Mendel-Mantoux skin testing and chest X-ray. In addition, T-cell reactivity towards tuberculin (PPD, purified protein derivative) and the Mycobacterium tuberculosis-specific proteins ESAT-6 and CFP-10 was determined ex vivo using a flow cytometric whole blood assay. RESULTS After standard screening, 15% of patients receiving TNF-alpha-blocking therapy were pretreated with isoniazide (INH), another 5% of patients did not receive TNF-alpha-blocking therapy because of LTBI. PPD-reactivity in the skin was observed in 14% of patients compared with 39% with the whole blood test. Analysis of the M. tuberculosis-specific response to ESAT-6 and CFP-10 revealed positive results in 16% of patients. Using a decision tree incorporating history, chest X-ray and either skin-test or ESAT-6/CFP-10 results, 18 or 22% of the patients, respectively, were classified as latently infected with M. tuberculosis. Four patients treated with INH because of a positive skin reaction did not show reactivity to ESAT-6/CFP-10 in the whole blood assays. Another six patients not pretreated with INH because of negative skin tests would have received INH, had the results of the whole blood assay been taken into account. CONCLUSION The Mendel-Mantoux skin test has a low sensitivity and specificity for the diagnosis of LTBI in this cohort of patients, potentially resulting in both over- and under-treatment with prophylactic INH when compared with the flow cytometric analysis of whole blood T-cell reactivity to proteins specific to M. tuberculosis. Use of T-cell based in vitro tests may help to refine diagnostic testing for LTBI.

Disruption of Extracellular Matrix Structure May Cause Pseudoachondroplasia Phenotypes in the Absence of Impaired Cartilage Oligomeric Matrix Protein Secretion

Pseudoachondroplasia and multiple epiphyseal dysplasia are two dominantly inherited chondrodysplasias associated with mutations in cartilage oligomeric matrix protein (COMP). The rarely available patient biopsies show lamellar inclusions in the endoplasmic reticulum. We studied the pathogenesis of these chondrodysplasias by expressing several disease-causing COMP mutations in bovine primary chondrocytes and found that COMP-associated chondrodysplasias are not exclusively storage diseases. Although COMP carrying the mutations D469Δ and D475N was retained within the endoplasmic reticulum, secretion of COMP H587R was only slightly retarded. All pseudoachondroplasia mutations impair cellular viability and cause a disruption of the extracellular matrix formed in alginate culture irrespective of the degree of cellular retention. The mutation D361Y associated with the clinically milder disease multiple epiphyseal dysplasia gave mild retention and limited matrix alterations, but the transfected cells showed normal viability. The effect of mutated COMP on matrix formation and cell-matrix interaction may be a major element in the pathogenesis of COMP-associated chondrodysplasias.

Animal models for arthritis

Animal models for rheumatic diseases complement human investigations to study in detail pathogenic hypotheses and therapeutic strategies. An overview of animal studies in the last years shows examples for ideas taken from bench to bedside and from bedside to bench. Depending on the disease studied, progress includes a refinement of physiological and pathogenic thinking and a better definition of promising cellular and molecular therapeutic targets.

Endocardial and myocardial involvement in systemic sclerosis – is there a relevant inflammatory component?

OBJECTIVES Myocardial manifestations of systemic sclerosis are mainly due to fibrotic remodeling. We report on two cases, where an endocardial and myocardial inflammation may be a relevant component of cardiac disease. CASE SERIES Case 1 presented with fulminant tricuspid failure in the absence of pulmonary hypertension and with newly developing systemic sclerosis. Myocardial biopsy and MRI supported endocardial and myocardial inflammation. Treatment with cyclophosphamide resulted in stabilization of cardiac function and normalization of cardiac enzymes. The patient died due to infectious complications. Case 2, also newly developed systemic sclerosis, presented with renal crisis and pulmonary alveolitis. Elevated cardiac troponin T persisted in the presence of cyclophosphamide treatment, subsequent MRI suggested myocardial inflammation. After stepping up treatment by addition of rituximab cardiac enzymes normalized and cardiac function stabilized. CONCLUSION We hypothesize that low-grade endocardial and myocardial inflammation may be more relevant in systemic sclerosis than appreciated previously.

Antitumor necrosis factor-α antibody-coupled gold nanorods as nanoprobes for molecular optoacoustic imaging in arthritis

Optoacoustic molecular imaging can provide spatially resolved information about the presence of molecular markers in vivo. We synthesized elongated gold nanorods having an absorption maximum in the range of 1064 nm modified with the antibodies infliximab and certolizumab for targeting TNF-α to detect inflammation in arthritic mouse knees. We showed an differential enhancement of optoacoustic signal amplitudes after the injection of infliximab-, but not certolizumab-modified and PEGylated control particles on arthritic and healthy control mice by using a fast-scanning optoacoustic imaging platform based on a pulsed Nd:YAG laser and a single focused ultrasound transducer. The excellent photoacoustic properties of the gold nanorods confirmed the overexpression of TNF-α in arthritic knees. Due to the uncomplicated coupling chemistry and the scalability of ultrasound-based imaging approaches, these results potentially allow a transfer to various preclinical and clinical applications. From the Clinical Editor: Gold nanorods were modified with TNF-α targeting antibodies and used to detect inflammation in arthritic mouse knees via optoaoustic imaging. A fast-scanning optoacoustic imaging platform based on a pulsed Nd:YAG laser and a single focused ultrasound transducer was utilized for imaging. The excellent photoacoustic properties of these gold nanorods confirmed the overexpression of TNF-α, paving the way towards further preclinical and future clinical applications.

Arthritis in patients with systemic sclerosis

BACKGROUND Systemic sclerosis (SSc) is a connective tissue diseases characterised by excessive thickening of the dermis in addition to affection of internal organs. Many patients experience musculoskeletal symptoms, but arthritis is still considered to be a rare manifestation. Therefore, we analysed a cohort of SSc patients in our department and related the findings to published data. METHODS Clinical data on inpatients with SSc between February 2007 and February 2008 were analysed retrospectively for the presence of clinically overt and documented arthritis. In addition, X-rays of these patients were reassessed. A systematic literature search using PubMed was performed to find studies on arthritis in SSc patients; suitable studies were included in a meta-analysis based on the random-effect-model. The search terms were scleroderma, systemic sclerosis, arthritis, inflammatory joint disease, hand involvement, foot involvement and musculoskeletal findings in various combinations. Original articles not written in English and articles which were not dealing with arthritis in SSc patients were excluded from the study. We included articles in which the examined cohorts corresponds to the ACR- or LeRoy criteria for SSc and arthritis was diagnosed based on clinical and/or radiological data. All manuscripts were read and reviewed by two independent investigators. RESULTS In our cohort of 58 patients, 31% had signs of arthritis, 19% clinically and 26% radiologically. In a meta-analysis of 7 studies, a prevalence of 26% (95% CI [16.7, 36.1]) for radiologically detectable arthritis in SSc patients was observed. For clinical arthritis, the prevalence was calculated to be 23% (95% CI [14.9, 30.9]). Of interest, no difference in the occurrence of arthritis in diffuse and limited SSc was observed radiologically (OR=1.1, 95% CI [0.47, 2.57]) or clinically (OR=1.11, 95% CI [0.6, 2.05]). CONCLUSION Arthritis is frequent manifestation of SSc. Its role in joint dysfunction has to be established in further studies.

Expression of Brachyury in mesenchymal progenitor cells leads to cartilage-like tissue that is resistant to the destructive effect of rheumatoid arthritis synovial fibroblasts

Our objectives were to determine the chondrogenic potential of a murine Brachyury‐transformed mesenchymal progenitor cell line in the presence of rheumatoid arthritis‐activated synovial fibroblasts (RASFs). Brachyury‐transformed mesenchymal progenitor cells were implanted alone or combined with RASFs isolated from diseased human joints in each of six immunodeficient SCID mice. De novo tissue formation was analysed by histology and immunohistochemistry after 60 days. Spheroid nodules resembling cartilage morphologically and by the expression of proteoglycans and collagen II developed in four of six implants in the absence and in five of six implants in the presence of RASFs. No evidence for hypertrophic differentiation could be observed. Mesenchymal progenitor cells transformed with Brachyury are able to produce a cartilage like tissue in vivo over an extended period of time that is resistant to the destructive effect of RASF. This observation may provide opportunities for a cell‐based reconstructive treatment in joint disease. Copyright