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ABSTRACT: Tenascin-C (TN-C) is expressed in the cartilage of osteoarthritis (OA). We examined whether TN-C was involved in cartilage repair of the diseased joints. Human articular cartilage samples were obtained from patients with OA and those with normal joints.
Immunohistochemistry testing of TN-C, chondroitin sulfate (CS), and proliferating cell nuclear antigen (PCNA) was performed. Chondrocytes were isolated from human cartilage and cultured. After treatment with TN-C, chondrocyte proliferation s was analyzed by bromodeoxyuridine (BrdU) incorporation assay using an enzyme-linked immunosorbent assay kit. Glycosaminoglycan content was determined by dimethylmethylene blue (DMMB) assay. The mRNA expression of aggrecan was also analyzed, by quantitative real-time polymerase chain reaction (PCR).
In osteoarthritic cartilage, increased TN-C staining was observed with the degeneration of articular cartilage in comparison with normal cartilage. TN-C staining was shown in the cartilage surface overlying CS-positive areas. In addition, the expression of PCNA in the positive areas for TN-C was significantly higher than that in the negative areas. Treatment of human articular chondrocytes with 10 μg/ml TN-C accelerated chondrocyte proliferation, increased the proteoglycan amount in culture, and increased the expression of aggrecan mRNA.
Our findings indicate that the distribution of TN-C is related to CS production and chondrocyte proliferation in osteoarthritic cartilage and that TN-C has effects on DNA synthesis, proteoglycan content, and aggrecan mRNA expression in vitro. TN-C may be responsible for repair in human osteoarthritic cartilage.
Journal of Orthopaedic Science 09/2010; 15(5):666-73. · 0.84 Impact Factor
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ABSTRACT: Osteopontin (OPN) is an extracellular matrix glycoprotein that has been recognized as a potential inflammatory cytokine. The function of OPN is modulated by protease digestion, and a thrombin-cleaved form of OPN is involved in the pathogenesis of various inflammatory disorders. We examined thrombin-cleaved OPN products in synovial fluid from patients with rheumatoid arthritis (RA) and osteoarthritis (OA).
Synovial fluid samples were obtained from knees of 20 patients with RA and 111 patients with OA. Thrombin-cleaved OPN product was determined using Western blotting. Levels of thrombin- cleaved and full-length OPN in synovial fluid were determined by ELISA. Synovia were analyzed by immunohistochemistry using an antibody specific to the thrombin-cleaved form.
Immunoblotting showed the presence of thrombin-cleaved OPN in synovial fluid from patients with RA and OA. ELISA results showed no difference between concentrations of full-length OPN in the synovial fluid of RA and OA patients; however, thrombin-cleaved OPN concentrations in RA synovial fluid samples were roughly 30-fold higher compared with OA samples (p < 0.001). Synovial fluid concentrations of thrombin-cleaved OPN in RA did not correlate with C-reactive protein levels. Immunohistochemistry of the synovium showed stronger reactivity in RA than in OA samples.
Local generation of thrombin-cleaved OPN was increased in RA joints. Thrombin-cleaved OPN may be a useful biochemical marker of RA.
The Journal of Rheumatology 02/2009; 36(2):240-5. · 3.69 Impact Factor
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ABSTRACT: The anatomic femoral component and Harris-Galante porous II (HGPII) cup were developed to provide more reliable bone ingrowth. We performed 20 cementless total hip arthroplasties (THAs) with anatomic stem/HGPII cup with 22-mm head in 14 consecutive patients, and evaluated the clinical and radiological results for a mean follow-up of 12.8 years. The all-anatomically designed stem provided excellent clinical and radiographic results. Four acetabular components underwent revision: three for fracture of the locking mechanism and wear of the polyethylene liner and one for the locking mechanism failure with dislocation of the HGPII cup. The abduction angles of the four revised acetabular components were apparently higher. The survivorship 13 years after surgery was 78%. Our findings show good long-term results using the anatomic femoral component, while the HGPII cup combined with 22-mm head seems to have poor durability due to locking mechanism failure.
International Orthopaedics 02/2008; 33(2):381-5. · 2.03 Impact Factor
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ABSTRACT: Expression of tenascin-C reappears in articular cartilage of persons with osteoarthritis (OA), while it is almost abolished in normal mature cartilage. Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is upregulated in OA cartilage and is involved in the progression of OA, and stimulates tenascin-C expression in other types of cells. We investigated regulation of tenascin-C expression by TNF-alpha through nuclear factor-alphaB (NF-kappaB) in OA cartilage in vivo and in vitro.
Human articular cartilages were obtained from patients with OA and immunofluorescence examination of tenascin-C and the activated RelA subunit was performed. Cultured chondrocytes isolated from human OA cartilage were treated with TNF-alpha and with SN50. Activation of RelA subunit of NF-kappaB was examined by immunolabeling. Changes in tenascin-C protein concentrations were determined by immunofluorescence of cells after monensin treatment and Western blot analysis of the cell lysates, and mRNA levels were analyzed by quantitative real-time polymerase chain reaction.
Increased intensity of tenascin-C staining was observed in the damaged cartilage compared with normal cartilage. Activated RelA staining in chondrocyte nuclei was prominent in tenascin-C-positive areas of OA cartilage. Treatment of cultured chondrocytes by TNF-alpha induced translocation of activated RelA to the nuclei, followed by upregulation of tenascin-C expression in both mRNA and protein. Treatment with SN50 inhibited increases of RelA and tenascin-C expression in chondrocytes.
TNF-alpha stimulated tenascin-C expression through NF-kappaB signaling with RelA activation in cultured OA chondrocytes, suggesting involvement of tenascin-C in OA cartilage remodeling.
The Journal of Rheumatology 02/2008; 35(1):147-52. · 3.69 Impact Factor
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ABSTRACT: Tenascin-C (TN-C) is a hexameric glycoprotein component of extracellular matrix, and alternative RNA splicing creates two major TN-C size variants (the small and large variants). The large TN-C variants play key roles in many pathologic conditions in adults, including tumorigenesis, regeneration, and inflammation. This cross-sectional study compared levels of large TN-C variants in synovial fluid of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Synovial fluid samples were obtained from knees of 26 patients with advanced RA and 79 with advanced OA. Expression of TN-C splice variants was examined using Western blotting. The levels of large TN-C variants in synovial fluid were determined by an enzyme-linked immunosorbent assay. Synovium were analyzed for TN-C by immunohistochemistry. Immunoblotting showed the presence of large TN-C variants in synovial fluid from patients with RA and OA. However, levels of large TN-C variants were fourfold higher in RA samples compared with OA samples (p < 0.01). Synovial fluid levels of TN-C in RA did not correlate with C-reactive protein levels. Immunohistochemistry of the synovium showed stronger reactivity in RA samples than in OA samples. These results indicate that local synthesis of TN-C is increased during rheumatic disease.
Journal of Orthopaedic Research 05/2007; 25(5):563-8. · 2.81 Impact Factor
