부산대학교 도서관

The PI3K/Akt signaling pathway has been implicated in playing an important role in platelet activation during hemostasis and thrombosis involving platelet‐matrix interaction and platelet aggregation. Its role in non‐physiological shear stress (NPSS)‐induced platelet activation relevant to high‐shear blood contacting medical devices (BCMDs) is unclear. In the context of blood cells flowing in BCMDs, platelets are subjected to NPSS (>100 Pa) with very short exposure time (<1 s). In this study, we investigated whether NPSS with short exposure time induces platelet activation through the PI3K/Akt signaling pathway. Healthy donor blood treated with or without PI3K inhibitor was subjected to NPSS (150 Pa) with short exposure time (0.5 s). Platelet activation indicated by the surface P‐selectin expression and activated glycoprotein (GP) IIb/IIIa was quantified using flow cytometry. The phosphorylation of Akt, activation of the PI3K signaling, was characterized by western blotting. Changes in adhesion behavior of NPSS‐sheared platelets on fibrinogen, collagen, and von Willebrand factor (vWF) were quantified with fluorescent microscopy by perfusing the NPSS‐sheared and PI3K inhibitor‐treated blood through fibrinogen, collagen, and vWF‐coated microcapillary tubes. The results showed that the PI3K/Akt signaling was involved with both NPSS‐induced platelet activation and platelet‐matrix interaction. NPSS‐sheared platelets exhibited exacerbated platelet adhesion on fibrinogen, but had diminished platelet adhesion on collagen and vWF. The inhibition of PI3K signaling reduced P‐selectin expression and GPIIb/IIIa activation with suppressed Akt phosphorylation and abolished NPSS‐enhanced platelet adhesion on fibrinogen in NPSS‐sheared blood. The inhibition of PI3K signaling can attenuate the adhesion of unsheared platelets (baseline) on collagen and vWF, while had no impact on adhesion of NPSS‐sheared platelets on collagen and vWF. This study confirmed the important role of PI3K/Akt signaling pathway in NPSS‐induced platelet activation. The finding of this study suggests that blocking PI3K/Akt signaling pathway could be a potential method to treat thrombosis in patients implanted with BCMDs. [ABSTRACT FROM AUTHOR]