What is the main function of von Willebrand factor?

What is the main function of von Willebrand factor?

• A. Bridges platelet GPIb to collagen
• B. Stabilizes Factor VIII
• C. Activates platelet aggregation
• D. Inhibits coagulation

Answer: (A)

von Willebrand factor’s primary job is to mediate initial platelet adhesion by acting as a bridge between platelets and exposed collagen at the injury site. When a vessel is damaged, collagen is exposed, and vWF binds to this collagen while also binding to the platelet receptor GPIb-IX-V. This tethering helps platelets stick to the damaged wall, especially in high-shear vessels, setting the stage for the platelet plug to form. A secondary role of von Willebrand factor is to stabilize Factor VIII in the circulation, prolonging its half-life and supporting the coagulation cascade. But vWF does not activate platelet aggregation directly, and it does not inhibit coagulation.

von Willebrand factor’s primary job is to mediate initial platelet adhesion by acting as a bridge between platelets and exposed collagen at the injury site. When a vessel is damaged, collagen is exposed, and vWF binds to this collagen while also binding to the platelet receptor GPIb-IX-V. This tethering helps platelets stick to the damaged wall, especially in high-shear vessels, setting the stage for the platelet plug to form.

A secondary role of von Willebrand factor is to stabilize Factor VIII in the circulation, prolonging its half-life and supporting the coagulation cascade. But vWF does not activate platelet aggregation directly, and it does not inhibit coagulation.