Platelet Aggregation

Platelet aggregation is the process by which platelets adhere to each other at sites of vascular injury, forming a platelet plug that is essential for hemostasis and the prevention of excessive bleeding. This process is also central to thrombosis, where inappropriate clot formation can lead to pathological conditions such as heart attack or stroke. The central event involves the activation of integrin αIIbβ3 (GPIIb/IIIa), which binds fibrinogen and von Willebrand factor (vWF), bridging adjacent platelets. Other receptors like P2Y1 and P2Y12 also play a role. It's a complex process influenced by shear stress and involves multiple pathways beyond just fibrinogen-αIIbβ3 bridging.

Targeted by antiplatelet drugs which inhibit various steps in the aggregation process, such as thromboxane A2 production or P2Y12 receptor signaling.