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).
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.
Recently, we showed that tetrasaccharide selectin ligand SiaLeX provided targeted delivery of liposomes loaded in the bilayer with melphalan lipophilic prodrug to tumour endothelium followed by severe injury of tumour vessels in a Lewis lung carcinoma model. Here, we study the impact of SiaLeX ligand on the interactions of liposomes with human umbilical vein endothelial cells (HUVEC) using flow cytometry, spectrofluorimetry and confocal microscopy. Liposomes composed of egg phosphatidylcholine/yeast phosphatidylinositol/1,2-dioleoyl glycerol ester of melphalan, 8:1:1, by mol, and varying percentages of lipophilic SiaLeX conjugate were labelled with BODIPY-phosphatidylcholine. The increase in SiaLeX content in liposomes led to a proportional increase in their uptake by cytokine-activated cells as opposed to non-activated HUVEC: for 10% SiaLeX liposomes, binding avidity and overall accumulation increased 14- and 6-fold, respectively. The early stages of intracellular traffic of targeted liposomes in the activated cells were monitored by co-localisation with the trackers of organelles. Endocytosis of SiaLeX liposomes occurred mostly via clathrin-independent pathways, which does not contradict the available literature data on E-selectin localisation in the plasma membrane. Using dual fluorescence labelling, with rhodamine-labelled phospholipid and calcein encapsulated at self-quenching concentrations, we found that SiaLeX liposomes undergo rapid (within minutes) internalisation by activated HUVEC accompanied by the disruption of liposomes; non-activated cells consumed a negligible dose of liposomes during at least 1.5h. Our data evidence the selective effect of SiaLeX formulations on activated endothelial cells and indicate their potential for intracellular delivery of melphalan lipophilic prodrug.
Oxidized forms of fibrinogen similarly to initial non-oxidized fibrinogen induced expression of P-selectin and ICAM-1 cell adhesion molecules in the cultured endothelial cells derived from human umbilical vein. The effect of oxidized fibrinogen on the expression of adhesion molecules was more pronounced. These data attest to more active participation of oxidized forms of fibrinogen into inflammation in the vascular wall, the first stage of atherogenesis.
Previously, we showed that incorporation of methotrexate (MTX) in the form of a lipophilic prodrug (MTXDG) in 100-nm lipid bilayer liposomes of egg phosphatidylcholine can allow one to reduce toxicity and improve the antitumor efficiency of MTX in a mouse model of T-cell leukemic lymphoma. However, in our hemocompatibility tests in vitro, MTX liposomes caused complement (C) activation, obviously due to binding on the liposome surface and fragmentation of the C3 complement factor. In this work, we studied the interactions of MTX liposomes carrying stabilizing molecules phosphatidylinositol (PI), ganglioside GM1, or a lipid conjugate of N-carboxymethylated oligoglycine (CMG) in the bilayer with subpopulations of human blood leukocytes. Liposomes labeled with BODIPY-phosphatidylcholine were incubated with whole blood (30 min and 1 h, 37C), blood cells were lysed with a hypotonic buffer, and the fluorescence of the liposomes bound but not internalized by the leukocytes was quenched by crystal violet. Cell suspensions were analyzed by flow cytometry. Incorporation of MTXDG dramatically enhanced the phagocytosis of liposomes of any composition by monocytes. Neutrophils consumed much less of the liposomes. Lymphocytes did not accumulate liposomes. The introduction of PI into MTX liposomes practically did not affect the specific consumption of liposomes by monocytes, while CMG was likely to increase the consumption rate regardless of the presence of MTXDG. The GM1 ganglioside presumably shielded MTX liposomes from phagocytosis by one of the monocyte populations and increased the efficiency of monocyte uptake by another population, probably one expressing C3b-binding receptors (C3b was detected on liposomes after incubation with blood plasma). MTX liposomes were shown to have different effects on TNF- production by activated leukocytes, depending on the structure of the stabilizing molecule.
Angiogenin isolated from cow milk induces the production of cytokines IL-1beta, IL-6, and TNF-alpha in human leukocytes; the level of production of each cytokine depends on the concentration of the preparation, and the dynamics of production depends on the time from the beginning of induction. Simultaneous treatment with angiogenin and phytohemagglutinin had an additive effect on the production of cytokines, the time of this effect manifestation being individual for each cytokine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.