The effect of pre-storage leukoreduction on the levels of expression and shedding of the pro-inflammatory molecule P-Sel in random PRP platelets

During storage, functional activity of platelets is affected by platelet storage lesion (PSL). The over-expression of P-Selectin is one of the most important evidence of platelet activation, thereby monitoring P-Sel expression and shedding can be considered as an index for performance in platelet concentrates. Ten PRP-platelet concentrates obtained from Tehran Regional Educational Blood Transfusion Center were subdivided into two groups of usual platelets and leuko-reduced platelets following pre-storage filtration. Flow-cytometery and ELISA were used to evaluate P-Sel expression and shedding, respectively. Data were analyzed by one way-Anova and Mann-Whitney U tests using Graphpad software. In filtered products, P-Sel expression on days 1, 3 and 5 after storage were 13.5 ± 1.8%, 15.2 ± 1.2% and 27.4 ± 2.5%, respectively. The results showed a sinificant increase of expression in day 5, compared to that in day 1 and 3. In non-filtered products, P-Sel expression on days 1, 3 and 5 were 7.4 ± 1.7%, 21 ± 2%, and 10 ± 2.2%, respectively. Increased expression in day 3 was followed by a significant decrease in day 5, that might be due to the loss of receptors via shedding and/or microparticulation during platelet post-activation. The levels of soluble P-Sel in filtered products were significantly less than unfiltered products in day 3. Considering the expression and shedding of P-Sel, this study proposes that the leuko-reduction process favor less PSL effect during the storage of platelet products.