p53 overexpression in synovial tissue from patients with early and longstanding rheumatoid arthritis compared with patients with reactive arthritis and osteoarthritis.
(41/3207)
OBJECTIVE: The p53 tumor suppressor gene is overexpressed in synovial tissue (ST) from patients with longstanding rheumatoid arthritis (RA), and may contain somatic mutations. The aim of this study was to determine p53 expression in ST from RA patients in different stages of the disease, compared with disease controls. METHODS: ST biopsy specimens were obtained from the knee joints of 31 RA patients in varying disease phases, 8 patients with reactive arthritis (ReA), 10 patients with inflammatory osteoarthritis (OA), and 6 control patients (4 with meniscus pathology, 2 with vascular insufficiency). ST was also obtained from the clinically uninvolved knee joints of 9 RA patients. Expression of p53 was determined by immunohistology with DO1 monoclonal antibody (mAb) in all patients and by Western blot analysis with DO7 mAb in a subgroup of the patients. RESULTS: The p53 protein was detected by immunohistology in 10 of the 13 patients with early RA (duration <6 months) and in 12 of the 14 patients with longstanding RA (duration >5 years). The p53 protein was also demonstrated in clinically uninvolved knee joints. Western blots revealed immunoreactive p53 in ST extracts from all RA patients. Expression of p53 was about twice as high in ST from patients with longstanding RA as in early RA samples, but the difference did not reach statistical significance. Small amounts of p53 were also detected in ST from ReA and OA patients, although the expression in RA synovium was significantly higher. Immunohistologic analysis of normal ST gave negative results for p53. CONCLUSION: This study shows that p53 overexpression is specific for RA, compared with OA and ReA. This phenomenon is probably secondary to increased production of wild-type p53 protein in response to DNA damage and secondary to somatic mutations caused by the genotoxic local environment in inflamed ST. Of interest, p53 overexpression can also be found in the earliest stages of RA and in clinically uninvolved joints. (+info)
C-myc antisense oligodeoxynucleotides can induce apoptosis and down-regulate Fas expression in rheumatoid synoviocytes.
(42/3207)
OBJECTIVE: To investigate the role of c-myc in the pathogenesis of rheumatoid arthritis (RA) and the mechanism of synovial apoptosis. METHODS: Using cultured human synoviocytes from patients with RA and c-myc antisense oligodeoxynucleotides (AS ODN), we examined the inhibition of cell proliferation by the MTT assay and the induction of apoptosis with TUNEL staining and fluorescence microscopy. In addition, the effect of c-myc on down-regulation of Fas expression was analyzed by flow cytometry, cytotoxicity assay, and reverse transcriptase-polymerase chain reaction. RESULTS: Treatment with c-myc AS ODN induced inhibition of cell proliferation, along with down-regulation of c-Myc protein and c-myc messenger RNA (mRNA) expression. The morphologic changes of synovial cell death were typical of apoptosis. In addition, c-myc AS ODN treatment down-regulated expression of Fas mRNA but not Fas antigen. Analysis of the involvement of the caspase cascade revealed that the cytotoxic activity of c-myc AS ODN was completely blocked by inhibitors of both caspase 1 (YVAD-FMK) and caspase 3 (DEVD-FMK). CONCLUSION: Our results strongly suggest that c-myc AS ODN might be a useful therapeutic tool in RA and clarify that cell death by c-myc AS ODN is induced through the caspase cascade, similar to Fas-induced apoptosis. In addition, combination therapy with anti-Fas antibody and c-myc AS ODN reduced Fas-dependent cytotoxicity. (+info)
Human interleukin-17: A T cell-derived proinflammatory cytokine produced by the rheumatoid synovium.
(43/3207)
OBJECTIVE: To investigate the presence and role of interleukin-17 (IL-17) in rheumatoid arthritis (RA), and its regulation by antiinflammatory cytokines. METHODS: The production of IL-17 was measured in supernatants of RA, osteoarthritis (OA), and normal synovial tissue pieces cultured ex vivo. Quantification of IL-17 was performed using a specific biologic assay. IL-17 gene expression was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR)-techniques. Immunohistochemistry was used to evaluate the frequency of IL-17-positive cells in synovium. The secretion of IL-17 by synovium was measured in the presence of IL-4, IL-13, and IL-10. In addition, the contributions of exogenous and endogenous IL-17 to IL-6 production by RA synovium were studied. RESULTS: Functional IL-17 was spontaneously produced by 16 of 18 RA (mean +/- SEM 41.7+/-11.4 units/ml), 2 of 12 OA (5.3+/-4.5 units/ml), and 0 of 3 normal synovial explant cultures. IL-17 messenger RNA expression was demonstrated by RT-PCR in 4 of 5 RA and 0 of 3 OA synovial samples. By immunostaining of RA synovium, IL-17-producing cells were found in the T cell-rich area. Addition of both IL-4 and IL-13 completely inhibited the production of IL-17, whereas IL-10 had no effect. Addition of exogenous IL-17 to RA synovium resulted in an increase in IL-6 production, whereas that of a blocking anti-IL-17 antibody reduced production of IL-6. CONCLUSION: The T cell cytokine IL-17 was found to be highly produced by RA, but not by OA, synovium. Its production and function were down-regulated by IL-4 and IL-13. These results indicate that IL-17 contributes to the active, proinflammatory pattern that is characteristic of RA. Through the contribution of IL-17, some Th1-like T cells appear to mediate synovial inflammation. (+info)
Blood-induced joint damage: a canine in vivo study.
(44/3207)
OBJECTIVE: To investigate the direct and indirect (via synovial inflammation) effects of intraarticular bleeding on cartilage in vivo. METHODS: Right knees of 14 beagle dogs were injected with autologous blood on days 0 and 2. Cartilage matrix proteoglycan turnover, collagen damage, and synovial inflammation of these knees, including the cartilage-destructive properties of the synovial tissue, were determined and compared with those of the left control knees on day 4 (short-term effects; n = 7) and day 16 (long-term effects; n = 7). RESULTS: Injected knees had a diminished content of proteoglycans in the cartilage matrix, and release of proteoglycans was enhanced (days 4 and 16). The synthesis of proteoglycans was significantly inhibited on day 4 but was enhanced on day 16. On day 4 more collagen was denatured in the injected joint than in the control joint; this effect was no longer detectable on day 16. Synovial tissue showed signs of inflammation on day 4 and day 16 but had cartilage-destructive properties only on day 16. CONCLUSION: In vivo exposure of articular cartilage to blood for a relatively short time results in lasting changes in chondrocyte activity and in cartilage matrix integrity, changes that may predict lasting joint damage over time. Interestingly, the direct effect of blood on cartilage precedes the indirect effect via synovial inflammation. (+info)
One-step reverse transcriptase PCR method for detection of Borrelia burgdorferi mRNA in mouse Lyme arthritis tissue samples.
(45/3207)
A one-step reverse transcriptase PCR (RT-PCR) method for detection of Borrelia burgdorferi mRNA in infected C3H mice is described. This simple procedure, less prone to nucleic acid cross-contamination than the standard method, was found to be 10-fold more sensitive than a classical two-step RT-PCR assay. By using one-step RT-PCR, flagellin mRNAs were detected in synovial and heart tissues from all seven infected mice tested. (+info)
Cytokine production by synovial T cells in rheumatoid arthritis.
(46/3207)
OBJECTIVE: To investigate the production of cytokines by T cells in patients with rheumatoid arthritis (RA), reactive arthritis (REA) and osteoarthritis (OA). METHODS: The lymphokines interleukin (IL)-2, IL-4, interferon gamma (IFN-gamma) and tumour necrosis factor beta (TNF-beta), as well as the monokines IL-1, IL-6 and TNF-alpha, were measured by immunoassays in sera and synovial fluid (SF) from patients with RA, REA and OA. In addition, cytokine expression was studied by immunohistochemistry in synovial membrane tissue sections from patients with RA and OA. RESULTS: Almost 60% of RA sera contained at least one of the cytokines investigated, though in low concentrations, whereas cytokines were generally not detectable in sera from REA and OA patients. In contrast, cytokines were found in virtually all SF; thus, the majority of SF from RA patients contained IFN-gamma (median level 17 pg/ml) in addition to the monokines IL-6 (4700 pg/ml) and TNF-alpha (157 pg/ml). IFN-gamma and IL-6 (but not TNF-alpha) were also frequently measured in SF from REA patients, whereas OA samples typically contained only IL-6. Immunohistochemical analysis of tissue sections from RA patients revealed lymphokine expression in 0.1-0.3% of T cells, particularly IL-2 and IFN-gamma, and to a lesser extent also IL-4. Interestingly, the expression of TNF-alpha and IL-6 by synovial T cells was also observed. The majority of cytokine-expressing T cells were CD4-positive T-helper cells typically found in perivascular areas, whereas cytokine-producing CD8-positive T cells were found distributed throughout the synovium. As expected, in specimens from OA patients, T cells were much less abundant and expression of cytokines could not be detected. CONCLUSION: These data clearly demonstrate production of cytokines by T cells in RA synovial tissue, indicating that activated T cells play a role in the pathophysiological events of RA. (+info)
Collagenase, cathepsin B and cathepsin L gene expression in the synovial membrane of patients with early inflammatory arthritis.
(47/3207)
OBJECTIVE: To examine the expression of the matrix metalloproteinase, MMP-1, and the cysteine proteases, cathepsin B (CB) and cathepsin L (CL), in the synovial membrane (SM) of patients with early inflammatory arthritis. METHODS: Samples of SM were obtained by blind needle biopsy or needle arthroscopy from inflamed knees of 28 patients with early inflammatory arthritis (mean disease duration 10.2 months, range 2 weeks-18 months). Sixteen patients had rheumatoid arthritis (RA), nine psoriatic arthritis and there was one each with ankylosing spondylitis, gout and an undifferentiated arthritis. Comparison was made with tissue from two patients with established erosive RA and three normal synovial tissue samples. In situ hybridization was performed using digoxigenin-labelled RNA probes. RESULTS: MMP-1, CB and CL were expressed in all patients with early arthritis and in established erosive RA, whereas normal synovium showed only scanty expression. The three proteases were prominent in perivascular infiltrates and endothelial cells of early arthritis tissue. MMP-1 was observed primarily in the lining layer, but was also evident in the sublining area. CB and CL were expressed to a lesser extent in the lining layer, and were present mainly in the subintima. The three proteases were not found in lymphoid aggregrates. No differences were observed between the disease categories. CONCLUSIONS: The detection of MMP-1, CB and CL in the synovium shortly after symptom onset implies that the potential for joint destruction exists at a very early stage in the disease. In addition, the perivascular and endothelial cell expression suggests a role for these proteases in mononuclear cell influx to the inflamed synovium and in angiogenesis. (+info)
Finger joint synovitis in rheumatoid arthritis: quantitative assessment by magnetic resonance imaging.
(48/3207)
OBJECTIVE: To assess quantitatively, by magnetic resonance imaging (MRI), the synovial membrane volume in second to fifth metacarpophalangeal (MCP) joints in patients with rheumatoid arthritis and healthy controls, and to compare the synovial membrane volumes with a more easily obtained semi-quantitative score for hypertrophic synovial membrane. PATIENTS AND METHODS: MCP joints of the dominant hand of 37 patients and five controls were examined clinically and by MRI. Laboratory assessments were performed. RESULTS: Median synovial membrane volumes were considerably larger in clinically active rheumatoid arthritis (RA) joints (e.g. 0.97 ml in the second MCP joint) than in clinically inactive joints (0.54 ml) and control joints (0.04 ml). Nevertheless, group distributions overlapped and marked volume differences were found within clinically uniform groups. The semi-quantitative score was highly correlated with the synovial volumes (Spearman rho = 0.79; P < 0.00001). Synovial membrane volumes were poorly related to the presence of rheumatoid factor and to laboratory markers of inflammation. CONCLUSION: These findings suggest that synovial membrane volumes, as determined by MRI, in finger joints are related to clinical signs of synovitis, but also that the volumes may vary more than what can be accounted for by the clinical appearances. A semi-quantitative score may be sufficient for more routine purposes. (+info)