Contribution of distinct adhesive interactions to platelet aggregation in flowing blood

Aggregation of blood platelets contributes to the arrest of bleeding at sites of vascular injury, but it can occlude atherosclerotic arteries and precipitate diseases such as myocardial infarction. The bonds that link platelets under flow conditions were identified using confocal videomicroscopy in real time. Glycoprotein (GP) Ib alpha and von Willebrand factor (VWF) acted in synergy with alpha(IIb)beta(3) and fibrinogen to sustain platelet accrual at the apex of thrombi where three-dimensional growth resulted in increasing shear rates. The specific function of distinct adhesion pathways in response to changing hemodynamic conditions helps to explain hemostatic and thrombotic processes. (C) 1999 by The American Society of Hematology.