PubMed Health⌕ Search

Biomedical subjects

D Baeten

Publications and source records attributed to D Baeten.

At least 37 records · Page 2Linked to original sources

Immunomodulatory effects of anti-tumor necrosis factor alpha therapy on synovium in spondylarthropathy: histologic findings in eight patients from an open-label pilot study.

OBJECTIVE: To assess the effects of treatment with anti-tumor necrosis factor alpha (anti-TNFalpha) on synovial histology in patients with spondylarthropathy (SpA) in order to confirm the effect on peripheral synovitis and to investigate the immunologic mechanisms involved in anti-TNFalpha therapy. METHODS: Patients with treatment-resistant SpA were treated with infliximab (5 mg/kg) at weeks 0, 2, and 6 in an open-label pilot study. In 8 patients, synovial biopsy tissues obtained at baseline, week 2, and week 12 were used for histologic and immunohistochemical evaluation. RESULTS: In all 8 patients (3 with ankylosing spondylitis, 1 with undifferentiated SpA, and 4 with psoriatic arthritis), there was a clear clinical improvement in the peripheral arthritis after anti-TNFalpha therapy. Histologic analysis of the synovial biopsy tissues indicated that the synovial lining layer thickness tended to decrease, with a significant reduction of CD55+ synoviocytes, at week 12. In the sublining layer, vascularity was reduced at week 12, with a decreased endothelial expression of vascular cell adhesion molecule 1 but not intercellular adhesion molecule 1, platelet endothelial cell adhesion molecule 1, and E-selectin. Although at week 2 and week 12, the number of neutrophils and CD68+ macrophages in the sublining layer was decreased, the overall degree of inflammatory infiltration remained unchanged. This could be related to the lymphocyte infiltration since at week 12, only CD4+ cells (but not CD3+, CD45RO+, and CD8+ cells) tended to decrease, while CD20+ lymphocytes and plasma cells were clearly increased. CONCLUSION: The reduction in lining layer thickness, vascularity, and infiltration with neutrophils and macrophages paralleled the beneficial effect of anti-TNFalpha therapy on peripheral synovitis in 8 patients with different subtypes of SpA. The adhesion molecule expression, T cell infiltration, and, most important, B cell infiltration seemed to contrast with previous observations in RA. Although these preliminary data need to be confirmed in a larger cohort, they suggest distinct immunomodulatory mechanisms of anti-TNFalpha in SpA.

Adjuvants, Immunologic↗

Expression of host defense scavenger receptors in spondylarthropathy.

OBJECTIVE: Reactive arthritis (ReA) is postulated to be caused by a defective host defense against gram-negative bacteria. HLA-B27 could play a role in this process, but does not account for the many HLA-B27 negative patients. The objective of this study was to test the expression of 3 macrophage scavenger receptors (SRs) that are responsible for innate immunity against gram-negative bacteria: SR class A type I (SR-AI), SR-AII, and the macrophage receptor with collagenous structure (MARCO). We postulate that defects in such receptors might also contribute to the host risk factors that increase the predisposition to ReA and perhaps other subtypes of spondylarthropathy (SpA). METHODS: Peripheral blood, synovial fluid, and synovial tissue samples were obtained from patients with recent Salmonella infection, ReA, other SpA, and rheumatoid arthritis (RA). The expression of SRs receptors was assessed by semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: Evaluation of the peripheral blood mononuclear cells (PBMC) from 4 patients who were recently infected with Salmonella, showed that PBMC from 2 patients who developed ReA expressed positive levels of MARCO, while PBMC from 2 patients who recovered from infection without sequelae did not. The synovial fluid mononuclear cells (SFMC) from some ReA patients expressed MARCO, but the levels were only moderate. The level of MARCO in the SFMC from the SpA patient group was low. In marked contrast, MARCO expression was high in almost all samples of RA SFMC. These findings also extended to synovial tissues. CONCLUSION: Expression of the host defense gene MARCO was susceptible to modulation, not only during infections, but also in the inflammatory arthritis conditions RA and SpA. MARCO is a variable to be considered as a candidate factor that might contribute to ReA.

Adolescent↗

Specific presence of intracellular citrullinated proteins in rheumatoid arthritis synovium: relevance to antifilaggrin autoantibodies.

OBJECTIVE: To investigate the presence of citrullinated proteins in the synovial membrane of patients with rheumatoid arthritis (RA) and controls, and to analyze a possible relationship with antifilaggrin autoantibody (AFA) reactivity. METHODS: Synovial biopsy samples were obtained from 88 consecutive patients undergoing needle arthroscopy for knee synovitis associated with RA (n = 36), spondylarthropathy (n = 35), osteoarthritis (n = 9), or other diagnoses (n = 8). Tissue sections were stained with 2 different anticitrulline polyclonal antibodies and an antifilaggrin monoclonal antibody (mAb). The phenotype of citrulline-positive cells and the colocalization with affinity-purified AFA were investigated by double immunofluorescence on frozen sections. RESULTS: Studies with the first antibody showed that citrulline is expressed intracellularly in the lining and sublining layers of RA synovial tissue. Staining with the second antibody, monospecific for proteins containing modified citrulline, and with anti-inducible nitric oxide synthetase confirmed the presence of citrullinated proteins rather than free citrulline in the synovium. Citrulline-positive cells were detected in 50% of the RA patients (18 of 36) but in none of the controls (0 of 52). The anticitrulline reactivity colocalized with affinity-purified AFA reactivity, although stainings with the antifilaggrin mAb indicated the absence of filaggrin in the synovium. CONCLUSION: Intracellular citrullinated proteins, which are not recognized by an antifilaggrin mAb, are expressed in RA but not in control synovium. The high specificity of this finding and the colocalization with AFA reactivity boost the interest in citrullinated proteins as possible triggers of autoimmune responses in RA. Moreover, this is the first description of a specific histologic marker for RA synovium.

Adult↗

The proportion of Th1 cells, which prevail in gut mucosa, is decreased in inflammatory bowel syndrome.

T lymphocytes and their cytokines have an important role in the regulation of immune responses in the gut and in the pathogenesis of intestinal inflammation such as in Crohn's disease. The aim of this study was to analyse the Th1/Th2 cytokine profile (IFN-gamma, IL-2, IL-4 and IL-10) in intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) in Crohn's disease (CD) and ulcerative colitis (UC) in relation to healthy controls (C). Colonic and ileal biopsy specimens were obtained from controls (n = 13) and patients with CD (n = 32). Colonic biopsies were obtained from patients with UC (n = 11). Intracytoplasmic IFN-gamma, IL-2, IL-4 and IL-10 were determined by flow cytometry after PMA-ionomycin stimulation in IEL and LPL. In colonic LPL, a significant proportional decrease of IFN-gamma and IL-2 producing CD3+ cells was observed in patients with CD and UC compared to controls. In ileal LPL, a similar tendency was found although differences were not significant. In IEL no differences in cytokine profiles could be observed. Flow cytometric analysis of intracytoplasmic cytokines at single cell level showed a proportional decrease of IFN-gamma and IL-2 producing T cells in colonic lamina propria in patients with inflammatory bowel disease.

Adolescent↗

Flow cytometric analysis of gut mucosal lymphocytes supports an impaired Th1 cytokine profile in spondyloarthropathy.

OBJECTIVE: To quantify the fraction of gut mucosal lymphocytes expressing the T helper type 1 (Th1) cytokines, interferon gamma (IFNgamma) and interleukin (IL)2, and the Th2 cytokines, IL4 and IL10, at the single cell level in patients with spondyloarthropathy (SpA) in comparison with healthy controls. METHODS: An improved extraction protocol was used for the enrichment of intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) from colonic and ileal biopsy specimens obtained from patients with SpA (n=20) and healthy controls (n=13). After stimulation with phorbol ester/ionomycin, expression of the intracellular cytokines IFNgamma, IL2, IL4, and IL10 was determined in CD3+, CD3+CD8+ and CD3+CD8- T cells by flow cytometry. RESULTS: In colonic LPLs, a significant decrease in IFNgamma-producing CD3+ cells was observed (p=0.02) in patients with SpA. In the CD3+CD8- subset, the proportion of cells producing IFNgamma and IL2 was decreased in patients with SpA (p=0.021 and p=0.027 respectively). In ileal LPLs, the percentage of IL10-producing CD3+CD8- cells was significantly increased (p=0.046). CONCLUSION: An impaired Th1 cytokine profile is observed in gut mucosal lymphocytes from patients with SpA. This adds to the existing evidence that the gut mucosal immune apparatus is involved in the pathogenesis of SpA.

Adult↗

Impaired Th1 cytokine production in spondyloarthropathy is restored by anti-TNFalpha.

OBJECTIVES: To evaluate the effect of anti-TNFalpha on the Th1 and Th2 cytokines in patients with spondyloarthropathy (SpA). METHODS: Peripheral blood mononuclear cells (PBMC) were obtained from 20 patients with active SpA treated with infliximab (5 mg/kg). For comparison, PBMC were also obtained from 15 healthy controls and 19 patients with active rheumatoid arthritis (RA). After stimulation with PMA/ionomycin, the intracellular cytokines interleukin (IL)2, IL4, IL10, and interferon (IFN)gamma were determined in CD3+ T cells and in CD3+/CD56+ natural killer (NK) T cells by flow cytometry. RESULTS: At baseline the percentage of T cells positive for IFNgamma (p=0.020) and IL2 (p=0.046) was decreased in patients with SpA compared with healthy controls, while IL10 (p=0.001) was increased. This cytokine profile, confirmed by the mean fluorescence intensities (MFI), was more pronounced in CD3+/CD8- cells and contrasted with higher IL2 production in RA. NK T cells, characterised by high IL4 and IL10 numbers, were also increased in patients with SpA (p=0.017). Treatment with infliximab induced a significant and persistent increase in IFNgamma and IL2 in patients with SpA. Moreover, there was a transient decrease in IL10 and NK T cells in patients with high baseline values, resulting in values comparable with those of healthy controls. This switch in cytokine profile was seen in both the CD3+/CD8- and CD3+/CD8+ subsets. CONCLUSIONS: Before treatment patients with SpA had an impaired Th1 cytokine profile compared with healthy controls and patients with RA. TNFalpha blockade induced restoration of the Th1 cytokines, resulting in a normal cytokine balance. These data confirm the effect of anti-TNFalpha on the immune changes in SpA, and provide insights into the mechanisms involved in TNFalpha blockade.

Adult↗

Culture of chondrocytes in alginate surrounded by fibrin gel: characteristics of the cells over a period of eight weeks.

OBJECTIVE: To produce tissue engineered cartilage by human articular chondrocytes in vitro for further use in in vivo manipulations for the treatment of cartilage defects. METHODS: Human articular chondrocytes were cultured in 0.5%, 1.0%, and 2.0% of alginate for up to four weeks. The optimal concentration of an alginate matrix for cell replication and for aggrecan synthesis by chondrocytes was determined. DNA content in the different culture conditions was measured after two and four weeks. Aggrecan synthesis rates and accumulation in the surrounding extracellular matrix were assessed by [(35)S]sulphate incorporation after the same periods of culture. To follow the outgrowth of chondrocytes from the alginate beads, chondrocytes were cultured for four weeks in 0.5 or 1.0% alginate surrounded by 0.25 or 0.5% fibrin gel. DNA content of each culture was measured after different culture periods. Finally, human chondrocytes in 1.0% alginate beads were embedded in 0.5% fibrin gel for eight weeks. Immunohistochemical analysis for aggrecan, type I and II collagen was performed weekly. RESULTS: At two weeks the DNA content in each culture significantly increased in 0.5 and 1.0% alginate cultures in comparison with baseline values. This increase continued until week 4 at the three alginate concentrations. Aggrecan synthesis at two weeks was highest in 0.5 and 1.0% alginate cell cultures. At four weeks aggrecan synthesis rates decreased independently of the alginate concentrations. Aggrecan mainly accumulated in the interterritorial matrix. Proliferation of chondrocytes in alginate and outgrowth of these cells in the surrounding fibrin gel were evident throughout the culture period. The accumulation of aggrecan and type II collagen around the cells, in alginate as well as in fibrin gel, gradually increased over the culture period. Type I collagen appeared after six weeks in alginate and in the surrounding fibrin. CONCLUSION: Human chondrocytes proliferate in this culture system, show an outgrowth into the surrounding fibrin, and synthesise a cartilage-like matrix for up to eight weeks.

Aggrecans↗

Chemical agents and enzymes used for the extraction of gut lymphocytes influence flow cytometric detection of T cell surface markers.

Chemical agents (DTT, EDTA) and enzymes (collagenase, DNAse) are often used for the generation of a single cell suspension from tissue samples. In this study, flow cytometry was used to examine the effect of chemical agents and enzymes on the expression of cell membrane markers of T lymphocytes from tonsils and peripheral blood. Expression of CD4, CD8, CD25, CD38, L-selectin, CD44, alphaEbeta7 and alpha4beta7 were studied. Incubation of lymphocytes with DTT and EDTA resulted in a decrease of CD38, alphaEbeta7 and alpha4beta7 expression. Incubation with collagenase A and DNAse resulted in a decrease of CD25, L-selectin, alphaEbeta7 and alpha4beta7. The results of this study indicate that a careful interpretation is necessary for phenotypic descriptions of lymphocyte populations obtained by enzymatic isolation techniques.

Adolescent↗

Human cartilage gp-39+,CD16+ monocytes in peripheral blood and synovium: correlation with joint destruction in rheumatoid arthritis.

OBJECTIVE: To investigate the expression of human cartilage (HC) gp-39, a possible autoantigen in rheumatoid arthritis (RA), in peripheral blood and synovium, to characterize its cellular source, and to analyze correlations with clinical features. METHODS: The expression of HC gp-39 in synovium and peripheral blood mononuclear cells (PBMC) was assessed by immunohistochemistry and flow cytometry. Synthesis and secretion were investigated by both reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: PBMC expressing HC gp-39 were increased in RA patients compared with spondylarthropathy patients (P = 0.0029) and with healthy control subjects (P = 0.0013). HC gp-39+ cells were also slightly overrepresented in RA synovium (P = 0.01). In both blood and synovium, HC gp-39+ cells were identified as CD14dim,CD16+ monocytes, a phenotype which can differentiate from classic CD14++ monocytes by maturation in vitro. HC gp-39 messenger RNA was detected in RA synovium and PBMC, and PBMC secreted HC gp-39 in vitro. The number of HC gp-39+ PBMC correlated with serum levels of C-reactive protein (r = 0.39, P = 0.003) and HC gp-39 (r = 0.52, P = 0.014). HC gp-39 expression in RA synovial lining correlated with joint destruction (r = 0.77, P < 0.001). CONCLUSION: CD16+ monocytes, a cellular source of HC gp-39 in vivo, are overrepresented in both RA peripheral blood and synovial tissue. The presence of HC gp-39+ cells in RA synovium is correlated with the degree of joint destruction. These data support a role of these cells in the local autoimmune response that leads to chronic inflammation and joint destruction.

Adipokines↗

Focal up-regulation of E-cadherin-catenin complex in inflamed bowel mucosa but reduced expression in ulcer-associated cell lineage.

The E-cadherin-catenin complex is important for the maintenance of epithelial architecture. We studied its expression in Crohn disease, ulcerative colitis, acute ileitis, and controls. Immunohistochemical stainings for E-cadherin, alpha-catenin, beta-catenin and gamma-catenin were performed. E-cadherin messenger RNA (mRNA) was detected using riboprobes. In active inflammation, there was up-regulation of the complex. In particular, epithelium adjacent to ulcers showed increased expression of protein and mRNA, but in ulcer-associated cell lineage, the intensity of staining was weak to negative. In focal inflammation, up-regulation was found in affected areas. Reparative epithelium growing over denuded areas showed weaker expression. Since structural or functional perturbation in any of the molecules of the E-cadherin-catenin complex results in loss of intercellular adhesion, the preexistent epithelium may benefit from up-regulation to try to maintain its normal architecture under inflammatory conditions. Reduced expression in reparative epithelium and ulcer-associated cell lineage could facilitate the motility of these cells.

Cadherins↗

Comparative study of the synovial histology in rheumatoid arthritis, spondyloarthropathy, and osteoarthritis: influence of disease duration and activity.

OBJECTIVES: To compare the macroscopic and microscopic characteristics of synovial tissue in rheumatoid arthritis (RA), spondyloarthropathy (SpA), and osteoarthritis (OA) after exclusion of possible biases induced by disease duration or activity, or both. METHODS: Synovial biopsy specimens were obtained by needle arthroscopy in patients with early RA (n=16), late RA (n=14), early SpA (n=23), and OA (n=12). Macroscopic and microscopic features were scored on a four point scale and analysed as a function of disease duration (early versus late RA), local and systemic disease activity, and diagnosis. RESULTS: Except for the maximal synovial lining thickness, no significant differences were seen between early and late RA. For disease activity, synovial histology was only weakly correlated with C reactive protein in RA, but seemed to be strongly dependent on effusion of the biopsied joint in all disease groups. After stratification for local disease activity, no disease related differences were found in patients without joint effusion. In contrast, important differences were found between patients with RA and SpA with active joint effusion. Synovial vascularity was macroscopically increased in SpA versus RA (p=0.017). A straight vessel pattern was only seen in RA, while tortuous vessels were preferentially seen in SpA. Vascularity was also microscopically increased in SpA compared with RA (p=0.031), and correlated with the macroscopic vascularity (r(s)=0.36, p=0.036). CD3+ (p=0.008), CD4+ (p=0.008), and CD20+ (p=0.024) lymphocytes were overrepresented in RA compared with SpA. The integrin expression in RA was characterised by a decrease of alphaVbeta3 in the synovial lining (p=0.006) and an increase of alphaVbeta5 in the sublining (p<0.001). CONCLUSIONS: The immune architecture of the synovial membrane is more dependent on local disease activity than on disease duration. Synovium obtained from clinically affected joints shows important histological differences between RA and SpA.

Adolescent↗

Subclinical gut inflammation in spondyloarthropathy patients is associated with upregulation of the E-cadherin/catenin complex.

OBJECTIVE: Previously an upregulation of E-cadherin and its associated molecules alpha-catenin, beta-catenin and plakoglobin has been demonstrated in clinically overt inflammatory bowel disease (IBD). The aim of this study was to investigate the expression of the E-cadherin/catenin complex in subclinically inflamed bowel mucosa from spondyloarthropathy (SpA) patients. METHODS: Ileal and colonic biopsy specimens from 19 SpA patients with subclinical inflammatory gut lesions and from seven controls were stained with monoclonal antibodies against E-cadherin, beta-catenin and plakoglobin and a polyclonal antibody against alpha-catenin. E-cadherin mRNA was detected using a riboprobe. Inflammation was histologically classified into acute, chronic active and chronic quiescent forms. RESULTS: In acute and chronic active bowel inflammation of SpA patients, upregulation of the E-cadherin/catenin glycoprotein complex could be observed. Chronic lesions in a quiescent state did not show such an upregulation. Furthermore, chronic inflammation was associated with an increase in E-cadherin mRNA. CONCLUSIONS: As some of the SpA patients with subclinical gut inflammation develop IBD, upregulation of the E-cadherin/catenin complex in inflamed bowel mucosa from SpA patients may point to early cellular changes in the development of IBD. However, at present it cannot be excluded that increased E-cadherin/catenin complex expression is a bystander phenomenon of active inflammation.

Acute Disease↗

Effects of a loading dose regimen of three infusions of chimeric monoclonal antibody to tumour necrosis factor alpha (infliximab) in spondyloarthropathy: an open pilot study.

OBJECTIVE: To evaluate the efficacy and safety of a loading dose regimen of three intravenous infusions with infliximab in patients with active spondyloarthropathy. METHODS: A monocentre, open-label pilot study of 21 patients with different subtypes of spondyloarthropathy was conducted. Treatment resistant patients with active disease (fulfilling inclusion criteria) received three infusions of 5 mg/kg infliximab (at weeks 0, 2, and 6). Standard clinical assessments were performed at baseline, and on days 3, 7, and 14, and from then on every two weeks. In patients who fulfilled criteria for ankylosing spondylitis, axial assessment was performed at baseline and on days 14, 42, and 84. RESULTS: In all global assessments (visual analogue scale of patient global assessment, patient pain assessment, doctor global assessment), erythrocyte sedimentation rate, and C reactive protein, a highly significant decrease could be seen already at day 3 (compared with baseline), which was maintained up to day 84. In patients with peripheral disease (n=18), tender and swollen joint count significantly decreased. In patients with axial disease (n=11), functional and disease activity indices significantly improved. Moreover in eight patients with psoriatic arthritis a significant decrease of the psoriasis area and severity index was observed. The treatment was well tolerated in all patients; no significant adverse events were seen. CONCLUSION: In this open-label pilot study of a loading dose regimen of three infusions of chimeric monoclonal antibody to tumour necrosis factor alpha in patients with active spondyloarthropathy, there was a fast and significant improvement of axial and peripheral articular manifestations, without major adverse experiences.

Adult↗

Needle arthroscopy of the knee with synovial biopsy sampling: technical experience in 150 patients.

Needle arthroscopy is an office-based technique allowing direct visualisation of the knee cavity and selective sampling of the synovial membrane. We performed needle arthroscopy in 150 patients with synovitis of the knee (1) to evaluate the diagnostic potential in early arthritis, (2) to perform therapeutic lavage in persistent inflammatory synovitis and (3) to assess the balance between technical feasibility, safety and patient comfort on the one hand, and the relevance of the obtained macro- and microscopic information for diagnosis and research purposes on the other. After disinfection of the leg and local anaesthesia of the skin and joint, a 1.8-2.7 mm needle arthroscope was introduced into the knee. Synovial fluid was aspirated and lavage of the joint cavity was performed to allow macroscopic evaluation of hyperaemia and hypertrophy of the synovial membrane. Biopsies were taken at inflamed sites, followed by another lavage to remove blood and debris. Needle arthroscopy of the knee is a simple and easy to perform technique made particularly attractive by the local anaesthesia and the ambulatory setting. It allows good macroscopic evaluation of synovial inflammation and selective sampling of the synovial membrane. Biopsies are suitable for RNA and DNA extraction, bacterial or lymphocyte culture, and cell isolation. Because samples were sometimes too small for representative histology, we switched from a 1.8 mm to a 2.7 mm biopsy forceps with good results. In nearly all cases the arthroscopy was well tolerated. Moreover, some patients reported relief of symptoms and even improvement of mobility after lavage of the inflamed joint. No major complications were noted. It was concluded that needle arthroscopy of the knee is a simple, safe and well-tolerated technique, with promising perspectives as a diagnostic, scientific and possibly therapeutic tool in rheumatic diseases.

Adolescent↗

A comparative phenotypical analysis of rheumatoid nodules and rheumatoid synovium with special reference to adhesion molecules and activation markers.

OBJECTIVES: (1) To analyse the in situ expression of adhesion molecules in rheumatoid nodules. (2) To compare the endothelial expression of adhesion molecules in synovial tissue and subcutaneous nodules obtained from the same patients. (3) To compare the expression of adhesion molecules and activation markers on T cell lines from nodules and synovium. METHODS: (1) Immunohistochemical analysis by APAAP technique of E selectin, CD44, ICAM-1, PECAM-1, and VCAM-1 was performed on 10 rheumatoid nodules from seven patients with rheumatoid arthritis (RA); nodules and synovium were simultaneously analysed from three patients. (2) T cell lines were generated from RA nodules (n = 7) and synovium (n = 7) by interleukin 2 expansion, and subsequently characterised by flow cytometry for surface expression of alpha E beta 7, alpha 4 beta 7, CD44, L selectin, LFA-1a, PECAM-1, and CD30. RESULTS: (1) In rheumatoid nodules, the palisading layer strongly stains for ICAM-1 and PECAM-1, but less pronounced for CD44. VCAM-1 staining was usually negative. ICAM-1 is upregulated in the vessels surrounding the central zone of fibrinoid necrosis. The immunohistological picture in different nodules derived from the same patient was similar. (2) The endothelial expression of adhesion molecules is comparable in RA nodules and synovium on an individual level, except for E selectin, which is overexpressed in nodule endothelium. (3) T cell lines from nodules and synovium display similar adhesion molecule profiles. However, the expression of CD30, a T cell activation marker linked with Th2 subsets, is higher in nodules compared with synovium. CONCLUSION: These data support a recirculation hypothesis of T cells between articular and extra-articular manifestations in RA, although the activation state of the T cells in each of these localisations may differ.

Adult↗