Blockade of P₂Y₁₂ and P₂Y₁ as well as PI3K p110β inhibition profoundly inhibits hypothermic ECC-induced P-selectin expression on platelets and platelet microparticles.

<p>Prior to (“before circ.”) and after hypothermic ECC (28°C, 30 minutes) flow cytometric analysis of P-selectin expression on platelets and PMPs was performed in groups treated with either PBS as control, 2-MeSAMP and MRS2179 (100 µM each; “P₂Y block”), propylene glycol (“PG”) as control, TGX-221 to inhibit PI3K p110β (2.2 µM; “TGX”) or a combination of 2-MeSAMP and MRS2179 (100 µM each) as well as TGX-221 (2.2 µM; “P₂Y block + TGX”). Representative dot plot indicating the identification of PMPs, single platelets and aggregates according to their size and granularity (A). Representative histogram overlay including a marker to identify percentages of P-selectin expressing platelets before circulation without additional stimulation (grey filled), before circulation with addition of ADP (20 µM; grey solid line) as well as 30 minutes after hypothermic ECC (black solid line) (B). Percentages of platelets (C) and PMPs (D) expressing P-selectin are depicted. Data in (C) and (D) are given as means (n = 6) and SD; groups were compared using RM-ANOVA with Bonferroni’s multiple comparison test; *p<0.05; **p<0.01, ***p<0.001.