AB0091 SYNDECAN-4 IS INCREASED IN OSTEOARTHRITIC KNEE, BUT NOT HIP OR SHOULDER, ARTICULAR HYPERTROPHIC CHONDROCYTES. (June 2019)

• Record Type: Journal Article
• Authors: Sanchez, Christelle; Lambert, Cécile; Dubuc, Jean-Emile; Bertrand, Jessica; Pap, Thomas; Henrotin, Yves
• Is Part Of: Annals of the rheumatic diseases. Volume 78(2019)Supplement 2
• Page Start: 1508
• Page End: 1508
• Publication Date: 2019-06
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2019-eular.1454
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: Syndecan-4 plays a critical role in cartilage degradation during osteoarthritis (OA). Objectives: To investigate the expression and localization of syndecan-4 in different OA joint tissues. Methods: Syndecan-4 mRNA levels were quantified by RT-PCR in human OA primary cells to compare non-hypertrophic vs hypertrophic articular chondrocytes, non-sclerotic vs sclerotic subchondral osteoblasts and normal/reactive vs inflamed fibroblasts-like synoviocytes. Syndecan-4 was localized by immunohistochemistry in knee, hip or shoulder OA bone/cartilage biopsies. Syndecan-4 was quantified by immmunoassay in chondrocytes culture supernatant and cell fraction. Results: By immunohistochemistry, syndecan-4 was observed in chondrocytes clusters in the superficial zone of OA knee, but not in OA hip or shoulder cartilage. No staining was observed in the deep zone of cartilage and in subchondral bone. No difference between syndecan-4 expression level in sclerotic and non-sclerotic osteoblasts was observed. Syndecan-4 tended to be increased in inflamed synoviocytes compared to normal/reactive ones but difference was not significant. Differentiated hypertrophic chondrocytes from knee, but not from hip cartilage, expressed more syndecan-4 than non-hypertrophic cells. Using an immunoassay for the extracellular domain of syndecan-4, we found 68% of the syndecan-4 in the culture supernatant of OA chondrocytes culture, suggesting that a large majority of the syndecan-4 is shed and released in the extracellular medium. The shedding rate was not affected by hypertrophic differentiation state of the chondrocytes or their joint origin. Conclusion: Syndecan-4 could be related to the hypertrophic differentiation of the OA chondrocytes, but the pathway seems to be knee specific. Even if chondrocytes clusters are seen in OA knee, hip and shoulder cartilage and hypertrophic differentiation appears in knee and hip OA articular chondrocytes, syndecan-4 synthesis only increased in knee. These findings suggests the presence of biochemical difference between articular cartilage according to their location and that syndecan-4 could be a biochemical marker specific for knee OA. Disclosure of Interests: None declared