Adhesion of thrombin-stimulated and unstimulated blood platelets to collagen in the presence of Proteus mirabilis lipopolysaccharides

Adhesion of blood platelets to collagen may be involved in pathogenesis of septic shock after damage of endothelial cells by LPS or inflammatory cytok ines. Therefore, analysis of platelet adhesion in the presence of endotoxin seems to be of great importance. We studied in vitro the effects of LPSs ( S1959, R110, R45) from Proteus mirabilis (smooth and rough types differing significantly in their composition) on the adhesion of unstimulated and thr ombin-stimulated platelets to collagen. The adhesion was measured by a stat ic method as absorbance of cell attached proteins. In this work we report t hat adhesion of resting platelets to collagen was stimulated by all tested LPSs. The effects were dependent on the doses of LPSs. In the presence of L PSs the inhibition of adhesion of thrombin-treated platelets to collagen wa s observed. The results presented in this paper indicate that LPSs from Pro teus mirabilis may act directly on blood platelets and stimulate adhesion o f resting platelets to collagen. On the other hand, LPSs can have an inhibi tory effect on adhesion of thrombin-stimulated platelets to collagen.