Connective tissue activation. xxxv. detection of connective tissue activating peptide–iii isoforms in synovium from osteoarthritis and rheumatoid arthritis patients: patterns of interaction with other synovial cytokines in cell culture

Objective. To determine whether extracts of unincubated osteoarthritis (OA) and rheumatoid arthritis (RA) synovial tissue contain connective tissue activating peptide–III (CTAP-III) isoforms and prostaglandin E₂ (PGE₂), and whether such extracts have growth-promoting activity, and to determine whether binary combinations of CTAP-III with other cytokines reported to be present in synovial tissue lead to synergistic, additive, or inhibitory effects on growth. Methods. Acid–ethanol extracts of human synovium were examined for growth-promoting activity by measuring formation of ¹⁴C-glycosaminoglycan (¹⁴CGAG) and ³H-DNA in synovial cell cultures; PGE₂ was measured by enzyme immunoassay, and CTAP-III isoforms were identified by Western blotting of extracted proteins separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Growth-promoting activity of CTAP-III and other cytokines was tested in synovial cultures treated with the agonists singly and in binary combination, by measuring changes in synthesis of ¹⁴C-GAG and ³H-DNA. Results. Platelet-derived CTAP-III and a cleavage isoform with the electrophoretic mobility of CTAP-III–des 1–15/neutrophil-activating peptide–2 (NAP-2) and PGE₂ were found in biologically active extracts of synovial samples from patients with RA and OA. Five growth factors (recombinant epidermal growth factor [rEGF], recombinant interleukin-1β [rIL-1β], basic fibroblast growth factor [bFGF], PGE₁, and PGE₂) in binary combination with CTAP-III showed synergism in stimulating GAG synthesis; two (recombinant platelet-derived growth factor type BB [rPDGF-BB] and recombinant transforming growth factor β [rTGFβ]) had an additive effect. In combination with CTAP-III, rEGF and rPDGF-BB had a synergistic effect in promoting DNA synthesis, rTGFβ and rbFGF had an additive effect, and rIL-1β, PGE₁, and PGE₂ were antagonistic. Conclusions. The results suggest that, in addition to endogenous factors, CTAP-III and other plateletderived cytokines may play roles in regulating synovial cell metabolism in RA and OA, and that combinations of growth factors may be more significant than single agents in amplification or suppression of important cell functions.     

Connective tissue activation. XXVIII. A connective tissue activating peptide from human urine

A protein factor in human urine which has the ability to activate connective tissue cells has been identified and partially purified; it appears to be different from epidermal growth factor and IgG. This urinary connective tissue activating factor (CTAP-U) is nondialyzable, labile to protease, stable to thiols, heat, and acid, and has an acidic isoelectric point. Purified preparations of CTAP-U have biologic activities that cause human connective tissue cells to synthesize incremental amounts of 14C-hyaluronic acid, 35S-proteoglycans, and 3H-DNA in vitro. The cell spectrum responsive to this substance includes human synovial cells, human chondrocytes, and skin fibroblasts. CTAP-U does not react with antisera to connective tissue activating peptide-III or to antibodies against IgG or its Fc and Fab fragments. Furthermore, CTAP-U does not cross-react in a radioreceptor assay for insulin, basic somatomedin, or epidermal growth factor-urogastrone. Utilizing standardized isolation conditions, CTAP-U preparations with these properties have been isolated from the urine of 6 normal individuals.     

Measurement of beta-thromboglobulin connective tissue activating peptide-III platelet antigen concentrations in pathologic synovial fluids

Concentrations of the human platelet proteins beta-thromboglobulin (beta-TG) and connective tissue activating peptide (CTAP)-III were measured in synovial fluid (SF) samples by radioimmunoassay of their common beta-T/CTAP antigen. beta-T/CTAP antigen concentrations were higher in rheumatoid SF than in samples from osteoarthritis patients. When concurrent SF and plasma samples were compared, SF antigen levels were weakly correlated with plasma antigen concentrations. Incubation of fresh polymorphonuclear leukocytes with antigen in SF resulted in apparent destruction of the antigen. Our study confirms the presence of a platelet-derived growth factor antigen in the pathologic joint, and suggests that leukocytes may participate in its clearance from inflamed joints.     

Neuropeptides in synovium of patients with rheumatoid arthritis and osteoarthritis

The presence of neural elements in synovial tissue proper has earlier been suggested on the basis of nonspecific silver impregnation techniques and is now confirmed in a study based on specific demonstration of cytoskeletal neurofilaments and various neuropeptides. With both the neurofilament and neuropeptide antisera, nerves were seen predominantly in a perivascular location, there being fewer nerves freely in the stromal tissue. In the synovium of patients with rheumatoid arthritis (RA), free stromal nerves stained with neurofilament antiserum often lacked neuropeptide immunoreactivity, while this was not the case in normal synovium or synovial samples from patients with osteoarthritis (OA). Furthermore, the intensity of staining of neurotransmitter peptides was weaker in RA than in OA or normal synovial tissue. It is suggested that neurogenic inflammation may play a role in RA and that neuropeptide nerves possibly release their mediators in RA.     

Virus antibodies in serum and synovial fluid of patients with rheumatoid arthritis and other connective tissue diseases.

Rubella and influenza A (H3N2) haemagglutination inhibition (HI) antibody titres and measles complement-fixing (CF), haemagglutination inhibition (HI), haemolysis inhibition (HLI), and ribonucleoprotein gel precipitation (RNP-GP) antibody titres were studied in the serum and synovial fluid of twenty patients with rheumatoid arthritis (RA), two patients with ankylosing spondylitis, and two patients with Reiter's syndrome. Antibody titres were also studied in the serum and CSF of four patients with systemic lupus erythematosus (SLE), one patient with dermatomyositis, and in the synovial fluid only of five patients with osteoarthritic knee effusions. Antibodies were found with each serological technique used in the synovial fluid of RA patients and the antibody titres were usually at about the same level as in the serum. The mean measles (HI, HLI, and RNP-GP) antibody titres were 4 to 6 times higher in the synovial fluid of RA patients than in synovial fluid of patients with osteoarthritic knee effusions, but a corresponding difference was not found in rubella and influenza A antibody titres. The mean measles antibody titres (CF, HI, HKI, and RNP-GP) were consistently higher in the synovial fluid of RA patients without rheumatoid factor than in the synovial fluid of RA patients with rheumatoid factor. In serum this difference was observed only with measles CF titres. The mean measles, antibody titres were consistently lower in the serum and synovial fluid of the RA patients without the synovial fluid haemolytic complement than in the RA patients with this haemolytic complement. No similar differences were found in the rubella and influenza antibody titres. No significant measles antibody titres were found in the CSF of patients with SLE or dermatomyositis.     

Extravascular fibrin formation and dissolution in synovial tissue of patients with osteoarthritis and rheumatoid arthritis.

Fibrin deposition is a prominent finding in the synovium of patients with rheumatoid arthritis (RA). Macrophages are found in increased numbers in RA synovium, and these cells are known to produce a variety of procoagulant and anticoagulant molecules. Using immunohistologic techniques, the content and distribution of several important components of the coagulation system in the synovium of patients with RA, osteoarthritis (OA), or traumatic joint abnormalities requiring surgery were investigated. Samples from 3 patients from each category were examined in detail. RA synovium (compared with that of patients with OA or joint trauma) had increased numbers of macrophages and increased expression/content of fibrinogen, tissue factor, factor XIII, tissue transglutaminase, cross-linked fibrin (fibrin D dimer), urokinase-type plasminogen activator, and alpha 2-plasmin inhibitor. Macrophage content in RA synovium was increased in both the lining cell areas and the interstitial cell areas. Fibrinogen was distributed throughout the tissue in all samples and was greater in RA synovium. In trauma and OA synovia, tissue factor was seen only in association with vessels (endothelial cells), but in RA synovium, it was markedly increased throughout the tissues. While fibrin D dimer was seen in small amounts in synovial lining cell areas of trauma and OA synovia, it was present in increased amounts in the lining cell and interstitial cell areas of RA synovium. Factor XIII and tissue transglutaminase were present in scant amounts in trauma and OA synovia, but there were increased amounts of both (especially tissue transglutaminase) in RA synovium in the vessel, lining cell, and interstitial cell areas. Urokinase and alpha 2-plasmin inhibitor were also markedly increased in RA synovium. These results suggest that in inflamed synovium, there is ongoing extravascular tissue fibrin formation and dissolution that correlates with the degree of inflammation and macrophage content. Extravascular coagulation/fibrinolysis in RA represents a potential target for therapeutic intervention in this disease.     

Complement activation in synovial fluid and tissue from patients with juvenile rheumatoid arthritis

Synovial fluid (SF) and synovial tissue from 10 patients with juvenile rheumatoid arthritis were examined. The SFs were heterogeneous with respect to the degree of complement activation. Quantification of C3dg and the terminal complement complex revealed a positive correlation between activation of the early and the late parts of the cascade in all patients. The amount of C-reactive protein and the number of white blood cells in the SF correlated significantly with the degree of complement activation. Weak deposits of C3, C3dg, or terminal complement complex were observed in a few vessels in the synovial tissue from 5 of the patients. There was no correlation between complement activity in SF and in the corresponding tissue. Furthermore, there was no correlation between clinical activity in the joints and the degree of complement activation. It is concluded that there is a discrepancy between synovial tissue and synovial fluid with respect to complement activation. C-reactive protein may, to some extent, be responsible for activation in SF, and the accumulation of white blood cells may be due to complement activation products.     

Intracellular oxidative activation in synovial fluid neutrophils from patients with rheumatoid arthritis but not from other arthritis patients

OBJECTIVE: To compare total and intracellular oxidative activation of blood and synovial fluid (SF) neutrophils from patients with rheumatoid arthritis (RA) and other arthritides with blood donor neutrophils. METHODS: Peripheral blood and SF samples were obtained from 26 gonarthritis patients (13 RA, 13 non-RA) attending the rheumatology unit for therapeutic joint aspiration. Isolated neutrophils were stimulated by a formylated tripeptide (fMLF) or by microbeads coated with collagen-I. Formation of superoxide-anion-derived reactive oxygen species (ROS) was studied by luminol-enhanced chemiluminescence. Paired samples of blood and SF neutrophils from patients with active arthritis were compared with blood neutrophils from patients in remission and from 47 healthy blood donors. RESULTS: SF neutrophils from patients with RA, but not from non-RA patients, showed high baseline intracellular ROS production. Blood neutrophils from arthritis patients in remission existed in a primed state as revealed by more rapid oxidative response after collagen-bead challenge and a more pronounced response after fMLF stimulation compared to healthy blood donors. Blood neutrophils from RA patients with ongoing gonarthritis, however, did not differ from healthy blood donors concerning oxidative activation, whereas blood neutrophils from non-RA patients with gonarthritis showed a significantly lower peak ROS production. CONCLUSIONS: A novel finding with pathogenetic implications in our study is that SF neutrophils from patients with RA, but not other arthritides, are activated and produce ROS intracellularly. This implies that synovial neutrophils in RA are engaged in the processing of endocytosed material.     

Expression of membrane-type matrix metalloproteinases in synovial tissue from patients with rheumatoid arthritis or osteoarthritis

We investigated the expression of membrane-type matrix metalloproteinase (MT-MMP) and matrix metalloproteinase (MMP) mRNAs in synovial tissue from patients with rheumatoid arthritis (RA, n = 5) or osteoarthritis (OA, n = 5) by Northern blot analysis. Northern analysis demonstrated strong expression of MT1-MMP, MT3-MMP, MMP-1, and MMP-3 and weak expression of MT2-MMP and MMP-8 in synovial tissue from patients with RA or OA. MT4-MMP was not detected. No significant difference was shown in the expression of MT-MMP mRNAs between RA and OA. Synovial tissue of RA or OA patients expressed MT-MMPs as well as MMPs. These results indicate that, in addition to MMPs, MT1-MMP, MT3-MMP, and probably MT2-MMP may play a role in the degradation of bone and cartilage matrix in RA and OA. Such information may provide a clue to the development of a novel therapeutic approach targeted on the prevention of joint destruction. Received: April 30, 2000 / Accepted: September 19, 2000     

Detection of stromelysin in synovial fluid and serum from patients with rheumatoid arthritis and osteoarthritis

Summary Stromelysin levels were measured using a one-step sandwich immunoassay in synovial fluid (SF) obtained from 31 patients with rheumatoid arthritis (RA) (31 samples) and 13 patients with osteoarthritis (OA) (13 samples) and in serum from 81 patients with RA (106 samples), 12 with OA (14 samples), 12 with gouty arthritis (gout) (14 samples), and 8 with osteoporosis (OP) (14 samples) to identify differences in the levels in these diseases as well as correlations with clinical parameters in RA. SF stromelysin levels were significantly higher in RA than in OA, and rose with increasing joint destruction in the former. No significant correlations were found between the SF stromelysin level in RA and various clinical parameters, except for the volume of SF which showed a correlation. Serum levels of stromelysin were highest in RA, gout, OA, and osteoporosis in decreasing order, and in RA were correlated with the Steinbrocker Stage. A significant correlation was also found between the serum stromelysin level and number of swollen joints, and correlations with the Lansbury index, ESR, CRP, WBC and Plt. The stromelysin level in SF was thought to be a useful parameter of local joint involvement and that in serum of the severity of systemic joint inflammation.     

Osteoprotegerin expression in synovial tissue from patients with rheumatoid arthritis,spondyloarthropathies and osteoarthritis and normal controls

OBJECTIVES: To demonstrate the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) in synovial tissue from rheumatoid arthritis (RA) patients, establish the cell lineage expressing OPG and compare the expression of OPG in RA, spondyloarthropathies, osteoarthritis and normal synovial tissue. METHODS: Synovial biopsy specimens were obtained at arthroscopy from 16 RA and 12 spondyloarthropathy patients with active synovitis of a knee joint, six RA patients with no evidence of active synovitis, 10 patients with osteoarthritis and 18 normal subjects. Immunohistological analysis was performed using monoclonal antibodies (mAb) to detect OPG and RANKL expression. In addition, dual immunohistochemical evaluation was performed with lineage-specific monoclonal antibodies (macrophages, fibroblasts and endothelial cells) and OPG to determine the cell lineages expressing OPG. The sections were evaluated by computer-assisted image analysis and semiquantitative analysis. RESULTS: Two patterns of OPG expression were seen, one exclusively in endothelial cells and one expressed predominantly in macrophages in the synovial lining layer. Both patterns of OPG staining could be blocked with excess recombinant OPG. Endothelial and synovial lining expression of OPG was seen in all synovial tissues except those from patients with active RA. In contrast, RANKL expression was seen predominantly in synovial tissue from patients with active disease, mainly in sublining regions, particularly within areas of lymphocyte infiltration. CONCLUSIONS: OPG expression on macrophage type synovial lining cells as well as endothelial cells is deficient in RA patients with active synovitis, in contrast to that seen in spondyloarthropathy patients with active synovitis. This deficiency in OPG expression in the inflamed joint of RA patients may be important in the development of radiologically defined joint erosions.     

Distribution of mast cells in human synovial tissue of patients with osteoarthritis and rheumatoid arthritis

Mast cells are demonstrated in synovial membranes of patients with osteo-arthritis and rheumatoid arthritis using a new staining principle based on interaction of heparin in mast cell granules with peroxidase labeled avidin. It was found that mast cell numbers in the subsynovial layer of patients with rheumatoid arthritis were significantly lower than those in patients suffering from osteo-arthritis. This decrease can be mainly attributed to patients with rheumatoid arthritis whose synovitis was characterized by a distinct histomorphological pattern consisting of lining cell ulcers and granulation tissue. However, when mast cell numbers in rheumatoid arthritis and osteo-arthritis patients were compared without respect to mast cell distribution in the subsynovial layer or the stratum fibrosum, no statistical differences between the diseases could be observed.     

Lymphocytes eluted from synovial tissue of juvenile rheumatoid arthritis patients.

Synovial tissues from 11 patients with juvenile rheumatoid arthritis were investigated. The elution of lymphocytes was performed according to a procedure previously described for synovial tissue of adult rheumatoid arthritis patients (1). The T lymphocytes were pre dominant (mean: 71%) in all cell suspensions studied, whereas the average proportion of B lymphocytes was 4%. In addition, Fc-receptor-bearing lymphocytes were demonstrable (mean: 8%). Transformation of the lymphocytes was induced by the unspecific mitrogens phytohemagglutinin, pokeweed mitogen, and concanavallin A, whereas antigens such as ppd and candida albicans antigen were usually ineffective.     

Connective tissue activation. XXXII. Structural and biologic characteristics of mesenchymal cell-derived connective tissue activating peptide-V

Connective tissue activating peptide-V (CTAP-V) is a single-chain, mesenchymal cell-derived anionic protein with large and small molecular forms (Mr of 28,000 and 16,000, respectively), as defined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proteins have similar specific activities with respect to stimulation of hyaluronic acid and DNA formation in human synovial fibroblast cultures. S-carboxymethylation or removal of sialic acid residues did not modify CTAP-V biologic activity. Rabbit antibodies raised separately against each of the purified CTAP-V proteins reacted, on immunodiffusion and on Western blot, with each antigen and neutralized mitogenic activity. The amino-terminal amino acid sequence of the CTAP-V proteins, determined by 2 laboratories, confirmed their structural similarities. The amino-terminal sequence through 37 residues was demonstrated for the smaller protein. The first 10 residues of CTAP-V (28 kd) were identical to the N-terminal decapeptide of CTAP-V (16 kd). The C-terminal sequence, determined by carboxypeptidase Y digestion, was the same for both CTAP-V molecular species. The 2 CTAP-V peptides had similar amino acid compositions, whether residues were expressed as a percent of the total or were normalized to mannose. Reduction of native CTAP-V protein released sulfhydryl groups in a protein:disulfide ratio of 1:2; this suggests that CTAP-V contains 2 intramolecular disulfide bonds. Clearly, CTAP-V is a glycoprotein. The carbohydrate content of CTAP-V (16 kd) and CTAP-V (28 kd) is 27% and 25%, respectively. CTAP-V may have significance in relation to autocrine mechanisms for growth regulation of connective tissue cells and other cell types.     

Characteristics of the protease activity in synovial fluid from patients with rheumatoid arthritis and osteoarthritis.

OBJECTIVE: To clarify which proteases are specifically activated in the lesions of rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: The activity levels of the serine proteases of the coagulation and fibrinolytic systems, and of elastase and collagenase as controls, in synovial fluid from 27 RA patients and 28 OA patients were measured using fluorogenic synthetic substrates which had methylcoumarylamide (MCA) at their COOH-termini. The thrombin-antithrombin III complex (TAT) content was also measured by ELISA. RESULTS: Among the proteases, thrombin-like activity was the highest in both RA and OA. The profiles of protease activity were similar in RA and OA, but their activities were in general significantly higher in RA than in OA (p < 0.01). The levels of both thrombin-like activity and TAT were about 7.5-fold higher in RA than in OA, while the levels of CRP and fibrinogen were only about 2-fold higher. Biochemical characterization of the thrombin-like activity in the synovial fluid of RA patients showed that this activity was due to thrombin. Thrombin-like activity positively correlated with the TAT concentration in RA (r = 0.750, p < 0.0001), but not in OA. CONCLUSION: Activation of the coagulation system was more marked in RA than in OA, strongly suggesting that in RA there is an imbalance between thrombin and its inhibitors, and that thrombin is more closely linked to the pathogenesis of RA than to that of OA. Our results also show that analysis of the synovial fluid may be useful to estimate the activation of the coagulation system in RA, but not that of the fibrinolytic system.     

Safety and efficacy of mizoribine in patients with connective tissue diseases other than rheumatoid arthritis

The objective of this study was to examine the safety and efficacy of mizoribine (MZR), an inhibitor of inosine monophosphate dehydrogenase, in patients with connective tissue diseases (CTDs) other than rheumatoid arthritis. We identified all patients who had ever been treated with MZR for CTDs at our institution during the period from January 2001 to May 2011. A retrospective review of medical records was performed to evaluate safety and efficacy of MZR. A total of 63 patients (13 induction and 50 maintenance therapy with MZR) were included. During 70.2 patient-years of follow-up, only one patient required discontinuation of MZR due to an adverse event. Doses of PSL were significantly decreased at last follow-up in both the induction (45.2 ± 15.6 vs. 8.4 ± 5.7 mg/day, p < 0.01) and the maintenance group (12.4 ± 7.6 vs. 9.3 ± 6.4 mg/day, p < 0.01). MZR appears to be a safe and well-tolerated steroid-sparing agent in patients with CTDs.