Hemostatic conditions following autologous transfusion of fresh vs stored platelets in experimental endotoxemia: an open-label randomized controlled trial with healthy volunteers

Background: Platelet increment is reportedly lower for maximum stored platelet concentrates (PCs) and during pyrexia, and in vitro function differs between fresh and stored PCs. However, little is known about the function of fresh and stored platelets during inflammation. Objectives: The aim was to study differences in hemostatic function after transfusion of fresh or stored PCs in a human model of experimental endotoxemia. Methods: Thirty-six healthy male subjects received either 2 ng/kg lipopolysaccharide (LPS) or a control (physiological saline 0.9%) and were randomly assigned to subsequently receive an autologous transfusion of either fresh (2-days-old) or stored (7-days-old) platelets, or saline control. Extracellular vesicles (EVs) were determined using flow cytometry, thrombin–antithrombin complex (TATc) was assessed using enzyme-linked immunosorbent assay, and hemostatic function was assessed using rotational thromboelastometry (ROTEM). Results: LPS infusion caused a marked increase in TATc, EVs and fibrinolysis. Thromboelastometry data revealed that following infusion of LPS, subjects exhibited in general a hypocoagulable state compared with those not receiving LPS. Platelet transfusions led to a reduced clotting time and an augmentation in clot strength, indicated by maximum clot firmness, solely among subjects undergoing endotoxemia. There were no significant differences in TATc or amount of EVs release after transfusion of fresh or stored platelets. Conclusion: A significant increase in TATc and EVs as well as a difference in hemostatic function after endotoxemia were observed. During endotoxemia, platelet transfusion resulted in enhanced coagulation and hemostatic function; however, no substantial differences were observed between transfusion of fresh or stored PCs.