Morphofunctional state of platelets in their concentrates depending on storage time

Background.Evaluation of the functional state of platelets in the composition of concentrates is necessary to improve the methods of their production, optimize storage conditions and terms, increase therapeutic efficacy, and reduce the risk of transfusion complications. Aim.Comprehensive study of the morphofunctional state of platelets during the storage of their concentrates. Material and methods.202samples of human platelet apheresis concentrates were studied for storage periods of up to 17days at a temperature of 2224C. The functional state of platelets was assessed using flow cytometry for the expression of P-selectin, active IIb3 integrin, and phosphatidylserines before and after biochemical stimulation. In addition, the mitochondrial potential of platelets, the concentration of intracellular adenosine triphosphate, contractile properties, induced aggregation, and morphological characteristics were studied according to scanning electron microscopy. Statistical analysis was performed by analysis of variance (ANOVA or KruskalWallis). Results.In non-activated platelets during storage, the spontaneous expression of P-selectin increased by an average of 7times, and phosphatidylserines by 3times. The induced expression of P-selectin, integrin IIb3 and phosphatidylserines was the highest on the day of receiving the concentrate and gradually decreased during storage to 1/2of the initial level. Platelet aggregation activity in response to collagen stimulation progressively decreased by an average of 100times, in response to the TRAP peptide by 1.5times. In contrast to the expression of activation markers, the ability of platelets to compress plasma clots in most samples changed slightly, within a few percent; in single samples, the contractile function dropped to zero by 47days of storage, which was combined with platelet hyperactivation and depletion. The mitochondrial potential of platelets and the content of adenosine triphosphate were relatively constant. Morphologically, discoid platelets predominated, however, starting from the 1st day of storage, spindle-shaped platelets, and from the 3rd day spherical forms and microaggregates of platelets accumulated. Conclusion.Platelets in the composition of concentrates initially have a high functional potential, which gradually decreases due to progressive spontaneous activation with a simultaneous decrease in reactivity and structural changes.