Endocrine journal
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We simultaneously measured the concentrations of parathyroid hormone related peptide (PTHrP) and cytokines in synovial fluid (SF) to clarify the relationship between PTHrP and cytokine network in the SF of elderly patients with arthritis. SF was collected from knee joints of five RA patients aged 66+/-11 years old and nine osteoarthritis (OA) patients aged 80+/-9 years old. PTHrP in SF was measured by enzyme-linked immunosorbent assay (ELISA), whereas tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8) in SF were all measured by ELISA. ⋯ In the culture of synovial cells from RA and OA, PTHrP was produced in RA more than OA after phorbol 12-mysistate 13-acetate (TPA) stimulation. These results indicate that PTHrP and cytokines, especially IL-6, might be involved in the inflammatory processes of elderly RA and OA. This is the first study in which PTHrP and cytokine levels were simultaneously examined in synovial fluid of elderly RA and OA.