von Willebrand Factor, Shear Stress, and ADAMTS13 in Hemostasis and Thrombosis

von Willebrand factor (VWF), an adhesive glycoprotein whose deficiency is best known for causing bleeding in patients with von Willebrand disease (VWD), is a complex molecule with a myriad of mysterious properties including its dependence on shear stress for adhesive functions. The discovery of ADAMTS13 has provided a critical impetus for understanding the regulation of VWF activity by shear stress. This communication reviews the current knowledge in VWF homeostasis and illustrates how this knowledge may help understand the changes affecting patients with various conditions including thrombotic thrombocytopenic purpura, VWD, hemolytic uremic syndrome, aortic stenosis, and ventricular assist devices.