Involvement of multiple adhesion receptor-ligand interactions in platelet aggregation under high shear flow. Under conditions of rapid blood flow (typically wall shear rates > 1000 s−1), the initial tethering of platelets to the surface of immobilized platelets involves VWF-GPIb interaction. This adhesive interaction is rapidly reversible and at shear rates up to 10 000 s−1 does not readily support stable platelet-platelet adhesion, resulting in platelet movement (translocation) across the thrombus surface. Platelet stimulation by one or more soluble agonists during translocation promotes the binding of VWF and fibronectin to integrin αIIbβ3, leading to sustained platelet-platelet adhesion. At elevated shear rates, the principal role of the fibrin(ogen)-integrin αIIbβ3 interaction is to stabilize formed aggregates.
