Inhibition of selectin-mediated cell adhesion and prevention of acute inflammation by nonanticoagulant sulfated saccharides - Studies with carboxyl-reduced and sulfated heparin and with trestatin A sulfate

Selectins play a major role in the inflammatory reaction by initiating neut rophil attachment to activated vascular endothelium, Some heparin preparati ons can interact with L- and P-selectin; however, the determinants required for inhibiting selectin-mediated cell adhesion have not yet been character ized. We now report that carboxyl-reduced and sulfated heparin (prepared by chemical modifications of porcine intestinal mucosal heparin leading to th e replacement of carboxylates by O-sulfate groups) and trestatin A sulfate (obtained by sulfation of trestatin A, a non-uronic pseudo-nonasaccharide e xtracted from Streptomyces dimorphogenes) exhibit strong anti-P-selectin an d anti-L-selectin activity while lacking antithrombin-mediated anticoagulan t activity. In vitro experiments revealed that both compounds inhibited P-s electin- and L-selectin-mediated cell adhesion under laminar flow condition s. Moreover, carboxyl-reduced and sulfated heparin and trestatin A sulfate were also active in vivo, as assessed by experiments showing 1) that microi nfusion of trestatin A sulfate reduced by 96% leukocyte rolling along rat m esenteric postcapillary venules and 2) that both compounds inhibited (by 58 -81%) neutrophil migration into thioglycollate-inflamed peritoneum of BALB/ c mice. These results indicate that nonanticoagulant sulfated saccharides t argeted at P-selectin and L-selectin may have therapeutic potential in infl ammatory disorders.