(408c) Blood Group Alters Platelet Binding Kinetics and Translocation Dynamics Under Arterial Shear

Platelets play a critical role in thrombosis and type O blood is associated with a lower risk of heart attack. It is known that the expression of blood group antigens alters platelet proteins. Understanding the coupling between platelet binding kinetics and the hydrodynamics of blood flow is essential to the mechanism of blood-type-specific platelet functions. In this study, we performed in-vitro experiments using microfluidic channels to compare the platelet adhesion dynamics between healthy type O and non-O blood¹. We explain our findings using a model² that takes into account both the platelet binding kinetics and the surrounding blood flow conditions.

The process of platelet adhesion is initiated by glycoprotein (GP)Ib and GPIIbIIIa receptors on the platelet surface binding with von Willebrand factor (VWF) on the vascular walls. The characteristic translocating motion of platelets near a VWF-bound surface is a net result of multiple bond formation and breaking events in channel flow. Based on our experimental measurements of the rate of platelet adhesion and the translocation velocity, we deduce from our theoretical model that the GPIb-VWF binding rate are significantly lower for type O compared to non-O platelets. Therefore platelets from type O donors interact less with VWF under arterial shear than non-O platelets. Our results suggest a potential mechanism for the reduced risk of myocardial infarction associated with blood type O.

1. E.Dunne, Q.M.Qi, E.S.G.Shaqfeh, J.M.O’Sullivan, I.Schoen, A.J.Ricco, J.O’Donnell and D.Kenny, “Blood group alters platelet binding kinetics to von Willebrand factor and consequently platelet function”, Blood, 133, 12 (2018).
2. Q.M.Qi, E.Dunne, I.Oglesby, J.Cowman, A.J.Ricco, D.Kenny and E.S.G.Shaqfeh, “In-vitro measurement and modeling of platelet adhesion on VWF-coated surfaces in channel flow”, Biophysical Journal, 116, 6 (2019)