Oral spermine administration inhibits nitric oxide-mediated intestinal damage and levels of systemic inflammatory mediators in a mouse endotoxin model

Enhanced intestinal nitric oxide production observed during sepsis is thought to play a central role in lipopolysaccharide-induced intestinal damage. In contrast intestinal polyamines, both from endogenous and exogenous origin, are essential for the maintenance of mucosal integrity. Polyamines have been shown to inhibit lipopolysaccharide-induced nitric oxide release in vitro and have been claimed to exert additional antiinflammatory actions. In this study, the effect of the polyamine spermine on the release of the proinflammatory mediators nitric oxide and tumor necrosis factor-alpha by a murine macrophage cell line was investigated. Furthermore, we investigated whether oral spermine administration inhibits lipopolysaccharide-induced intestinal inducible nitric oxide synthase and nitrotyrosine expression and modulates the release of inflammatory mediators. Our results show that although spermine inhibited lipopolysaccharide-induced nitric oxide release in a murine macrophage cell line, no effect on tumor necrosis factor-alpha or release was observed. In addition, oral spermine administration inhibited intestinal inducible nitric oxide synthase and nitrotyrosine expression suggesting a protective effect of spermine on lipopolysaccharide-induced intestinal damage. In parallel a decrease in serum levels of the proinflammatory mediators nitrate, nitrite, and interferon-gamma and an increase in the antiinflammatory cytokine interleukin-10 was observed, although tumor necrosis factor-alpha levels were unaffected. These results indicate that spermine inhibits lipopolysaccharide-induced nitric oxide release in vitro as well as in vivo. Further, intraluminally derived polyamines modulate the systemic immune response. It is concluded that oral spermine administration might have therapeutic perspectives for several disorders characterized by systemic inflammation and intestinal damage.