Von Willebrand factor

Von Willebrand factor is a multimeric glycoprotein which appears to be one of the most important clotting factors providing an implementation of bleeding stop mechanism. This hemostatic protein represents a poly-functional molecule which performs its physiologic functions by taking an active part in initiation of platelets adhesion in the area of vessel endothelium damage. Moreover, von Willebrand factor bonds with collagen which is exposed when a vessel wall is damaged. Another important feature of von Willebrand factor is co-factor activity related to clotting factor VIII, manifesting in stabilization of the latter, providing its physiological clearance and its delivery to the vessel endothelium damage site. Genetically determined quantitative or qualitative von Willebrand factor deficiency leads to development of the most frequent hemostasis system disease — von Willebrand disease. The unique feature of von Willebrand factor is a waveform pattern of its functional activity. Von Willebrand factor may also appear as a ligand for large platelet integrin αIIbβ3 (GPIIb/IIIa). The role of von Willebrand factor in angiogenesis process is currently actively studied. It was shown that absence of von Willebrand factor promotes processes of angiogenesis which is manifested in significant increase of proliferation rate of endothelium cells in vitro.