Collagenase 3 production by human osteoarthritic chondrocytes in response to growth factors and cytokines is a function of the physiologic state of the cells.
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OBJECTIVE: We investigated the response of human osteoarthritic (OA) chondrocytes, in terms of collagenase 3 production, to growth factors and cytokines involved in the anabolism and catabolism of articular cartilage, and explored the major signaling pathways leading to its up-regulation. METHODS: Human OA chondrocytes were treated with the following factors: the proinflammatory cytokine interleukin-1beta (IL-1beta), the growth factors basic fibroblast growth factor (bFGF), platelet-derived growth factor BB (PDGF-BB), parathyroid hormone (PTH), insulin-like growth factor 1 (IGF-1), transforming growth factor gamma1 (TGFbeta1), and TGFbeta2, the protein kinase (PK) activator antagonists for PKC, PKA, and PKG pathways, and phospholipase A2 and tyrosine kinases, as well as the antiinflammatory cytokines IL-4, IL-10, and IL-13. Collagenase 3 expression and synthesis were determined. Comparison was made with collagenase 1. RESULTS: The human OA chondrocyte population could be divided into 2 categories: the L chondrocytes, showing low collagenase 3 basal synthesis levels and high sensitivity to IL-1beta stimulation; and the H chondrocytes, high collagenase 3 basal synthesis levels and low IL-1beta inducibility. In L chondrocytes, all growth factors stimulated collagenase 3 production. In H chondrocytes, PTH, IGF-1, and TGFbeta had little or no impact; bFGF slightly stimulated it and PDGF-BB showed the same pattern as in the L chondrocytes. The effects of all growth factors, except TGFbeta, on collagenase 1 synthesis followed those of collagenase 3, albeit to a higher degree. Interestingly and unlike collagenase 3, the effects of TGFbeta on collagenase 1 could not be related to the state of the cells, but rather, depended on the isoform. Indeed, TGFbeta2 did not induce collagenase 1 synthesis, whereas TGFbeta1 stimulated it. Among the PK activators tested, phorbol myristate acetate was the strongest inducer, suggesting a major involvement of the PKC pathway. IL-13 inhibited collagenase 3 production, IL-4 had little effect, and IL-10 had none. CONCLUSION: This study shows that collagenase 3 production in human OA chondrocytes depends on the physiologic state of the cell. TGFbeta might be responsible for the change in cells from the L to the H state. Importantly, our in vitro data implicate TGFbeta2 as a possible in vivo agent capable of specifically triggering collagenase 3 production over that of collagenase 1 in OA cartilage. (+info)
Treatment with calcitonin suppresses the responses of bone, cartilage, and synovium in the early stages of canine experimental osteoarthritis and significantly reduces the severity of the cartilage lesions.
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OBJECTIVE: To relate the rate of bone resorption to serum levels of both hyaluronan (HA) and antigenic keratan sulfate (KS) in canine experimental osteoarthritis (OA) and to evaluate the effects of calcitonin on these parameters and the OA lesions of the unstable knee. METHODS: Twenty-two dogs underwent anterior cruciate ligament transection (ACLT) and 6 dogs underwent sham operation. Urinary pyridinium crosslinks were quantified by high-performance liquid chromatography. Immunoassays quantified hyaluronan (HA) and antigenic KS. Macroscopic and histologic OA lesions were scored. Calcitonin treatment was started on day 14 postsurgery and stopped on either day 49 or day 104 postsurgery. Control dogs and all treated dogs were killed on day 105. RESULTS: All ACLT joints developed OA. In contrast to sham-operated animals, all operated dogs exhibited an early and sustained rise in the levels of their urinary and serum markers. Calcitonin markedly reduced the levels of these markers and the severity of OA lesions. Furthermore, the longer the period of calcitonin therapy, the lower the score of the OA lesions. CONCLUSION: Bone, synovium, and articular cartilage all appear to be involved in the state of hypermetabolism that develops in unstable joints. Furthermore, the rate of bone resorption increases markedly in the early stages of this OA model and is likely to contribute to cartilage breakdown. Since calcitonin reduced the severity of OA changes, this form of therapy may have benefits for humans who have recently experienced a traumatic knee injury. (+info)
Altered mechanics of cartilage with osteoarthritis: human osteoarthritis and an experimental model of joint degeneration.
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OBJECTIVE: Studies of cartilage mechanics seek to determine the fundamental relationships between mechanical behavior and the composition and structure of healthy cartilage and to determine mechanisms for changes associated with degeneration. METHOD: The mechanics of normal and osteoarthritic (OA) human articular cartilage are reviewed. Studies of the initiation and pathogenesis of cartilage degeneration in the anterior cruciate ligament transection (ACLT) model of joint instability are also presented. RESULTS: In human cartilage with OA, tensile, compressive and shear behaviors are dramatically altered. These changes present as decreases in the modulus or stiffness of OA cartilage in tension, compression and shear loading, and increases in the propensity to swell as compared to healthy cartilage. In the ACL transection model of OA, similar changes in the mechanics of cartilage have been observed. In addition, changes in structure, composition, and as metabolism consistent with human OA have been found. Deterioration of the collagen-proteoglycan solid network, which appears to be focused at the articular surface, has been the earliest cartilage changes in the model. It remains to be determined if the initial disruption of the cartilage surface is a direct result of mechanical forces or a product of altered chondrocyte activity. CONCLUSIONS: These data and continued research using experimental models of OA provide a basis for our understanding of the pathogenesis and the time course of events in OA and will lead to the development of better procedures for disease intervention and treatment. (+info)
Animal models of arthritis: relevance to human disease.
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Animal models of arthritis are used to evaluate potential antiarthritis drugs for clinical use. Therefore capacity of the model to predict efficacy in human disease is one of the most important criteria in model selection. Animal models of rheumatoid arthritis (RA) with a proven track record of predictability include rat adjuvant arthritis, rat type II collagen arthritis, mouse type II collagen arthritis, and antigen-induced arthritis in several species. Agents currently in clinical use (or trials) that are active in these models include corticosteroids, methotrexate, nonsteroidal anti-inflammatory drugs, cyclosporin A, leflunomide, interleukin-1 receptor antagonist, and soluble tumor necrosis factor receptors. For some of these agents, the models also predict that toxicities seen at higher doses for prolonged periods would preclude dosing in humans at levels that might provide disease-modifying effects. Animal models of osteoarthritis (OA) include mouse and guinea pig spontaneous OA, meniscectomy and ligament transection in guinea pigs, meniscectomy in rabbits, and meniscectomy and cruciate transection in dogs. None of these models have a proven track record of predictability in human disease because there are no agents that have been proven to provide anything other than symptomatic relief in human OA. Efficacy data and features of the various models of RA and OA are discussed with emphasis on their proven relevance to human disease. (+info)
5'-Nucleotidase as a marker of both general and local inflammation in rheumatoid arthritis patients.
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OBJECTIVES: To evaluate measurements of serum and synovial fluid 5'-nucleotidase (5'N) activity as a marker of general and local inflammation in arthritis, and to resolve a contradiction in the literature as to whether or not the activity of 5'N in the synovial fluids of rheumatoid arthritis (RA) patients is raised in comparison with that in the synovial fluids of other arthritis patients. METHODS: Assays for 5'N were carried out in the presence of inhibitors of other phosphatases, AMP deaminase and of 5'N itself. RESULTS: The 5'N activity in the synovial fluid of RA patients was both significantly higher (mean 1.7-fold) and had a greater variance than that in the synovial fluids of other arthritis patients, and the contradiction in the literature was resolved. There was a strong correlation between the 5'N activity in the sera of RA patients and their erythrocyte sedimentation rate. There was no significant correlation between the 5'N in the serum and synovial fluid for the RA patients, in marked contrast to the strong correlation between the two 5'N activities shown by the osteoarthritis patients. The 5'N activity was greater in the synovial fluid than in the serum for virtually all the patients, showing that it was being made locally. CONCLUSIONS: The 5'N activity in the serum (which came mostly from the liver) could be used as a marker of general inflammation, whereas the 5'N in the synovial fluid was mostly produced locally, and could be used as a marker of joint inflammation, particularly for the RA patients. (+info)
Immunohistochemical study of Fas antigen expression in synovial tissues from patients with rheumatoid arthritis.
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OBJECTIVE: To investigate the location and expression of Fas (Apo-1, CD-95) antigen in synovial tissue from rheumatoid arthritis (RA). METHODS: Immunohistochemical technique was used to identify the location and expression of Fas antigen in synovial tissues from 27 RA, 11 osteoarthritis (OA), 7 ankloysing spondylitis (AS), 3 pigmented villo-hyperplastic synovitis, 1 juvenile rheumatoid (JRA) patients and 5 "normal" control subjects. RESULTS: Fas was strongly expressed by synoviocytes and infiltrated lymphocytes in approximately two-thirds of RA patients (16/27). However, only weak expression occurred on lymphocytes in 3 of 11 OA, 1 of 7 AS patients and 1 of 5 "normal" subjects. The stain-positive substance in the forms of rings, granules, or dust was deposited on the cell membrane and in cytoplasm. CONCLUSION: The expression of Fas may be involved in the mechanism of synovium proliferation and abnormal activation of local lymphocytes in RA. (+info)
Type IX collagen immunoreactive peptides in synovial fluids from arthritis patients.
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OBJECTIVES: To determine whether type IX collagen-related peptides can be detected in the synovial fluids of arthritis patients and to assess their potential as molecular markers of arthritis. PATIENTS/METHODS: Synovial fluids from a set of carefully diagnosed arthritis patients and from healthy volunteers were used. Hydroxyproline assays were carried out to determine the content and concentration of collagen. Collagen cross-link determinations were conducted by reversed-phase HPLC. SDS PAGE and immunoblotting were used to identify the collagenous components, and N-terminal sequencing was performed to confirm these identities. RESULTS: All the synovial fluids were found to contain measurable amounts of collagen at similar concentrations. This appeared to be mainly high-molecular-weight material consisting of type I and type IX collagens, but not type II collagen. However, other smaller molecular weight type IX immunoreactive peptides were detected which were more apparent in the synovial fluids from arthritis patients. These peptides were also found to contain non-collagenous material. Collagen cross-links were also present in the arthritis synovial fluids. CONCLUSION: Collagenous material can be detected in all synovial fluids and the presence of pyridinoline cross-links indicates that at least some of this is derived from a mature collagen matrix. Type IX immunoreactive peptides were identified, but were found to contain significant amounts of non-collagenous material, and their presence, even at lower levels, in synovial fluids from normal subjects limits their potential for use as molecular markers of disease. Nevertheless, this is the first report of type IX collagen-related fragments in synovial fluids. (+info)
Chondroitin sulphation patterns in synovial fluid in osteoarthritis subsets.
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OBJECTIVES: To determine concentrations of chondroitin sulphate (CS) disaccharides in knee synovial fluid (SF) from normal subjects and patients with osteoarthritis (OA) or rheumatoid arthritis (RA), to test whether these variables differ between different diseases and subsets of OA. METHODS: OA was subdivided into large joint OA (LJOA), nodal generalised OA (NGOA), and OA with calcium pyrophosphate crystal deposition (CPA), with 25, 9, and 11 people in each subset respectively. The SF of 13 normal subjects was also volunteered for analysis along with 15 RA patients. Clinical assessment of inflammation (0-6) was undertaken on OA and RA knees. Concentrations of unsaturated CS disaccharides Deltadi6S and Deltadi4S were measured by capillary zone electrophoresis. RESULTS: Concentrations of Deltadi6S were lower in RA (5.90 ng/ml) and OA (13.24 ng/ml) fluids compared with normal (21.0 ng/ml) but no significant differences were seen between disease and normal fluids for Deltadi4S (about 4-6 ng/ml). The ratio of Deltadi6S:Deltadi4S were RA+info)