Erythrocyte-Derived Microparticles Supporting Activated Protein C-Mediated Regulation of Blood Coagulation

摘要: Elevated levels of erythrocyte-derived microparticles are present in the circulation medical conditions affecting red blood cells. Erythrocyte-derived expose phosphatidylserine thus providing a suitable surface for procoagulant reactions leading to thrombin formation via tenase and prothrombinase complexes. Patients with elevated circulating have increased generation vivo. The aim study was investigate whether able support anticoagulant protein C system. were isolated using ultracentrifugation after incubation freshly prepared erythrocytes ionophore A23187 or from outdated erythrocyte concentrates, different preparations yielding similar results. According flow cytometry analysis, exposed phoshatidylserine bound lactadherin, annexin V, S, which is cofactor activated C. assemble complexes stimulate plasma-based assay both presence absence added tissue factor. addition inhibited dose-dependent fashion. effect by monoclonal antibody that prevents binding S also attenuated anti-TFPI antibodies. In microparticles, degrading cofactors FVIIIa FVa, respectively. Protein stimulated Arg306-cleavage whereas efficient inhibition depended on synergistic activity FV. summary, microparticle system, may be important balance initiation propagation coagulation