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Oxidatively-modified fibrinogen induces platelet aggregation and potentiates ADP-induced platelet aggregation and production of active oxygen forms in zymosan-stimulated leukocytes. Fibrinogen induces IL-8 production in primary culture of endothelial cells from human umbilical vein; the oxidized form of fibrinogen is more active, similarly as during induction of the expression cell adhesion molecules (P-selectin and ICAM-1). Oxidized fibrinogen (10 and 20% oxidation degree) impairs microrheological properties of the blood, sharply reduces erythrocyte deformability, modifies blood viscosity, and reduces suspension stability of the blood. Oxidized fibrinogen modified blood clotting parameters and ADP-, ristocetin-, and collagen-induced platelet aggregation in whole blood. Oxidized fibrinogen disordered the formation of fibrin clot and blood clotting process. Platelet aggregation was activated in response to ADP, but not to ristocetin and collagen, the degree of activation increased in direct proportion to the degree of fibrinogen oxidation. This indicates the "dysregulatory" effect of oxidized fibrinogen on platelets. The formation of platelet complexes with polymorphonuclear leukocytes was intensified in the presence of oxidized fibrinogen; polymorphonuclear leukocyte luminol-dependent fluorescence intensity in the presence of platelets increased after incubation with oxidized fibrinogen in comparison with native fibrinogen. Hence, oxidized fibrinogen plays an important role in the development of atherosclerosis and its complications (thromboses).

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We studied hemolytic activity of gold nanoparticles added to the whole blood (ex vivo) and of nanoparticles coated and not coated with plasma components on erythrocytes in hypotonic medium (osmotic hemolysis) in vitro. Gold nanoparticles did not stimulate erythrocyte hemolysis after 4-h incubation with the whole blood ex vivo. Hemolysis tended to increase in the presence of small gold nanoparticles (5, 10, 20 nm) at the maximum concentration of 20 μM (by gold content) used in our study in comparison with the control. This tendency was detected during the 1st hour of the nanoparticles incubation with blood. Gold nanoparticles in the used concentrations (up to 20 μM of gold) coated with plasma components after preincubation with autologous plasma and nanoparticles without coating caused no osmotic hemolysis of erythrocytes in vitro.