title: Interleukin-1-induced interleukin-6 is required for the inhibition of proteoglycan synthesis by interleukin-1 in human articular cartilage.
abstract: Cartilage from normal controls, patients with osteoarthritis, and patients with rheumatoid arthritis produced no interleukin-6 (IL-6) in culture. However, IL-1 induced massive production of IL-6 (up to 135 ng/ml) in cartilage from all 3 sources, in a dose-dependent manner (in some cases, a peak value was reached). The levels of induced IL-6 were similar to those found in rheumatoid arthritis synovial fluid. At IL-1 concentrations that induced almost complete inhibition of proteoglycan (PG) synthesis, IL-6 production could still be increased considerably. Exogenous IL-6 inhibited PG synthesis by up to 25%. IL-1-induced inhibition of PG synthesis was reversed by antibodies against recombinant human IL-6. These results suggest that IL-6 is required for the IL-1-induced inhibition of PG synthesis.
authors.affiliation: Department of Rheumatology, University Hospital, Utrecht, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Nietfeld
authors.forename: B
authors.initials: B
authors.lastname: Wilbrink
authors.forename: M
authors.initials: M
authors.lastname: Helle
authors.forename: J L
authors.initials: JL
authors.lastname: van Roy
authors.forename: W
authors.initials: W
authors.lastname: den Otter
authors.forename: A J
authors.initials: AJ
authors.lastname: Swaak
authors.forename: O
authors.initials: O
authors.lastname: Huber-Bruning
mesh_terms: D000328:Adult; D000367:Age Factors; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism*; D002675:Child, Preschool; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology / Q000502:physiology*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D010003:Osteoarthritis / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000494:pharmacology; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D011509:Proteoglycans; D011994:Recombinant Proteins