Effect of the late complement components C5b-9 and of platelet-derived growth factor on the prostaglandin release of human synovial fibroblast-like cells.

We examined the prostaglandin E (PGE) synthesis of cultured adherent synovial fibroblast-like cells (SFC) from patients with osteoarthritis (OA) in the noninflammatory state as well as with rheumatoid arthritis (RA). In cells from RA patients the spontaneous PGE release was generally higher compared to that of OA patients, but decreased fast with time in culture. After cell passage, similar PGE baseline levels were seen in cells of the two patient groups. The cells could then be stimulated by the terminal complement components C5b-9 or C5b-8. PGE synthesis was also stimulated by the platelet-derived growth factor (PDGF), interleukin-1 (IL-1), or lipopolysaccharide (LPS). The amount of PGE synthesis after incubation with PDGF, LPS and IL-1 was comparable to that released after C5b-9. Thus, like other inflammatory mediators C5b-9 and PDGF trigger the increased PGE production by SFC and thus may participate in the development of synovial inflammation and contribute to the pathogenesis of RA.