Molecular Mechanism of Shear Stress-Induced Platelet Aggregation

Blood circulating in vessels is exposed to shear stress caused by the force necessary to produce flow; the difference in velocity between layers situated at varying distances from the vessel wall determines the shear rate, which is directly proportional to the shear force and inversely proportional to the viscosity of blood. Previous studies have demonstrated that exposure of platelets to shear stress leads to aggregation in the absence of exogenous agonists (1) (2). Under high shear stress, which may mimic the rheological situation existing in certain districts of the arterial circulation, von Willebrand factor (vWf) may have a crucial role in the formation of the irreversible platelet aggregates (3) (4) . However, the precise molecular mechanism of shear stress-induced platelet aggregation (SIPA) has yet to be clarified.