The prostaglandin analogs, misoprostol and SC-46275, potently inhibit cytokine release from activated human monocytes

Inflammatory mediator release is one of the body's responses to tissue injury and inflammation. These mediators, such as interleukin-1 beta (I1-1 beta), tumor necrosis factor (TNF-alpha), and products of arachidonic acid metabolism, are themselves proinflammatory. Purified human monocytes stimulated in vitro with E. coli-derived lipopolysaccharide (LPS) will release these key cytokines along with various other eicosanoid mediators. Monocytes incubated with LPS and the prostaglandin E-1 analog, misoprostol, released significantly lower levels of cytokines compared to monocytes incubated with LPS alone. Eicosanoid release was also affected by misoprostol. SC-46275, a more potent mucosal protective PGE1 analog, also altered the release of cytokines and eicosanoids from human monocytes. However SC-46275 inhibited I1-1 beta release with an IC50 value of 9 microM compared to 75 microM for misoprostol. SC-46275 and misoprostol both inhibited TNF-alpha release. These data suggest there is a potential immunomodulatory role for prostaglandin analogs in the therapeutic treatment of inflammatory diseases such as ulcerative colitis, Crohn's disease, and autoimmune inflammatory diseases of the central nervous system.