Effects of fucoidans and heparin on reactions of neutrophils induced by IL-8 and C5a.

Fucose-containing sulfated polysaccharides (fucoidans) from brown algae exhibit anti-inflammatory activity in vivo, however, there is only limited knowledge about their mode of action. Potential targets may be the chemokine interleukin 8 (IL-8) and the anaphylatoxin C5a, as they are closely linked to inflammatory processes. In this study, two fucoidans from Saccharina latissima and Fucus vesiculosus, and unfractionated heparin (UFH) were examined for their binding properties to IL-8 and C5a and their effects on IL-8- and C5a-induced reactions of polymorphonuclear neutrophils (PMN). As proved by a competitive sulfated polysaccharide-coating-ELISA, both fucoidans bind to IL-8 and C5a, whereby they showed higher affinity to IL-8. Whereas UFH displayed only moderate effects, the fucoidans concentration-dependently reduced the IL-8- and C5a-induced intracellular calcium release, Erk1/2 phosphorylation and chemotaxis of PMN. Their inhibitory potency is dependent on the target protein, but also other aspects than the binding turned out to play a role.