title: Peroxynitrite may affect fibrinolysis via the reduction of platelet-related fibrinolysis resistance and alteration of clot structure.
abstract: We tested the hypothesis that in vitro peroxynitrite (ONOO(-), a product of activated inflammatory cells) may affect fibrinolysis in human blood through the reduction of platelet-related fibrinolysis resistance. It was found that ONOO(-) (25-300 µM) accelerated lysis of platelet-fibrin clots (in PRP) dose-dependently, whereas fibrinolysis of platelet-free clots was slightly inhibited by ≥ 1000 µM stressor. Concentrations of ONOO(-) affecting the lysis of platelet-rich clots, inhibited clot retraction (CR) in a dose-dependent manner. Thromboelastometry (ROTEM) measurements performed in PRP showed that treatment with ONOO(-) (threshold conc. 100 µM) prolongs clotting time, and reduces alpha angle, and clot formation velocity parameters indicating for reduced thrombin formation rate. In PRP, ONOO(-) (threshold conc. 100 µM) reduced the collagen-evoked exposure of phosphatidylserine (PS) on platelets' plasma membrane, the shedding of platelet-derived microparticles (PMP), and inhibited platelet-dependent thrombin generation (measured in artificial system), dose-dependently. As judged by confocal microscopy, similar ONOO(-) concentrations altered the architecture of clots formed in collagen-treated PRP. Clots formed in the presence of ONOO(-) were less dense and were composed of thicker fibers, which make them more susceptible to lysis. In platelet-depleted plasma, ONOO(-) (up to milimolar concentration) did not alter clot structure. Blockage of PS exposed on platelets resulted in an alteration of clot architecture toward more prone to lysis. ONOO(-), at lysis-affecting concentrations, inhibited the collagen-evoked secretion of fibrinolytic inhibitors from platelets. We conclude that physiologically relevant ONOO(-) concentrations may accelerate the lysis of platelet-fibrin clots predominantly via downregulation of platelet-related mechanisms including: platelet secretion, clot retraction, platelet procoagulant response, and the alteration in clot architecture associated with it.
authors.affiliation: Department of Physical Chemistry, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Misztal
authors.affiliation: Department of Physical Chemistry, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Rusak
authors.affiliation: Department of Biology, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Brańska-Januszewska
authors.affiliation: Department of Biology, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland.
authors.forename: Halina
authors.initials: H
authors.lastname: Ostrowska
authors.affiliation: Department of Physical Chemistry, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland. Electronic address: mtomask@umb.edu.pl.
authors.forename: Marian
authors.initials: M
authors.lastname: Tomasiak
mesh_terms: D000293:Adolescent; D000328:Adult; D001777:Blood Coagulation / Q000502:physiology*; D001792:Blood Platelets / Q000378:metabolism*; D005260:Female; D005342:Fibrinolysis / Q000502:physiology*; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D030421:Peroxynitrous Acid / Q000378:metabolism*; D055815:Young Adult
chemical_list: D030421:Peroxynitrous Acid
keywords: Clot structure; Fibrinolysis; Inflammation; Peroxynitrite; Platelet-related fibrinolysis resistance; Platelets