The aim of this study was to determine if the anticytokine neuropeptide α- melanocyte-stimulating hormone (a-MSH) occurs, along with interleukin 1 receptor antagonist (IL-lra) and soluble tumor necrosis factor receptor (sTNFr), in synovial fluid of patients with rheumatoid arthritis (RA), juvenile chronic arthritis (JCA), or osteoarthritis. The data show that α-MSH does occur in the synovial fluid and its concentrations are greater in patients with RA than in those with osteoarthritis. Synovial fluid concentrations of IL-lra and sTNFr were likewise greater in RA. Further, concentrations of α-MSH, IL-l-ra, and sTNFr were greater in patients with polyarticular/systemic-onset JCA than in those with pauciarticular disease, that is in patients with greater joint inflammation. Concentrations of α-MSH were greater in synovial fluid than in plasma in a substantial proportion of patients, suggesting local production of the peptide; this is the first indication that the anticytokine molecule a-MSH is produced within a site of inflammation. Further, it appears that local production of α-MSH is induced particularly in those arthritic joints that have more intense inflammatory reactions. This finding, combined with previous evidence of the marked anti-inflammatory activity of α-MSH, suggests that the peptide acts locally to modulate proinflammatory influences in rheumatic diseases.
- Arthritis, juvenile chronic
- Interleukin-1 receptor antagonist
- Rheumatoid arthritis
- Tumor necrosis factor receptor, soluble
- α-Melanocyte stimulating hormone
ASJC Scopus subject areas
- Endocrine and Autonomic Systems