Interleukin-6 is elevated in synovial fluid of patients with focal cartilage defects and stimulates cartilage matrix production in an in vitro regeneration model

AI Tsuchida, Michiel Beekhuizen, M (Marijn) Rutgers, Gerjo van Osch, JEJ (Joris) Bekkers, AGJ Bot, B Geurts, WJA Dhert, DBF Saris, LB Creemers

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Abstract

Introduction: This study aimed to determine whether, as in osteoarthritis, increased levels of interleukin-6 (IL-6) are present in the synovial fluid of patients with symptomatic cartilage defects and whether this IL-6 affects cartilage regeneration as well as the cartilage in the degenerated knee. Methods: IL-6 concentrations were determined by ELISA in synovial fluid and in conditioned media of chondrocytes regenerating cartilage. Chondrocytes were obtained from donors with symptomatic cartilage defects, healthy and osteoarthritic donors. The effect of IL-6 on cartilage regeneration and on metabolism of the resident cartilage in the knee was studied by both inhibition of endogenous IL-6 and addition of IL-6, in a regeneration model and in osteoarthritic explants in the presence of synovi Results: Synovial fluid of patients with symptomatic cartilage defects contained more IL-6 than synovial fluid of healthy donors (P = 0.001) and did not differ from osteoarthritic donors. IL-6 production of osteoarthritic chondrocytes during cartilage regeneration was higher than that of healthy and defect chondrocytes (P < 0.001). Adding IL-6 increased GAG production by healthy chondrocytes and decreased GAG release by osteoarthritic chondrocytes (P < 0.05). Inhibition of IL-6 present in osteoa Conclusions: Our results support a modest anabolic role for IL-6 in cartilage matrix production. Targeting multiple cytokines, including IL-6, may be effective in improving cartilage repair in symptomatic cartilage defects and osteoarthritis.
Original languageUndefined/Unknown
JournalArthritis Research & Therapy
Volume14
Issue number6
DOIs
Publication statusPublished - 2012

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