What is the receptor for von Willebrand factor?
Two distinct platelets receptor for VWF, the glycoprotein GPIbα in the GPIb-IX-V complex and the integrin αIIbβ3 (GPIIb-IIIa complex) are localised on platelet membrane.
What is the role of von Willebrand factor?
Von Willebrand factor (VWF) is a large multimeric glycoprotein that performs two critical functions in primary hemostasis: it acts as a bridging molecule at sites of vascular injury for normal platelet adhesion, and under high shear conditions, it promotes platelet aggregation.
Where is von Willebrand factor expressed?
Von Willebrand factor (VWF) is a highly adhesive procoagulant molecule that mediates platelet adhesion to endothelial and subendothelial surfaces. Normally it is expressed exclusively in endothelial cells (ECs) and megakaryocytes.
How does vasopressin work in von Willebrand disease?
DDAVP is used as a hemostatic agent for the treatment of von Willebrand’s disease. However, its cellular mechanisms of action have not been elucidated. DDAVP, a specific agonist for the vasopressin V2 receptor (V2R), exerts its antidiuretic effect via a rise in cAMP in kidney collecting ducts.
How is von Willebrand factor activated?
The protein is activated by flowing blood and thus has the potential to stimulate the formation of blood clots even in the absence of vessel damage. In order to prevent unnecessary clotting, VWF is regulated by an enzyme known as ADAMTS13.
Is von Willebrand a coagulation factor?
Von Willebrand factor is involved in the early stages of blood clotting, and also carries the important clotting protein factor VIII. In people with VWD, the amount of Von Willebrand factor clotting protein in the blood is lower than normal or doesn’t work as it should.
What are the roles of the von Willebrand factor in primary hemostasis and secondary hemostasis?
In primary hemostasis it binds to the platelet glycoprotein 1b and links it to the injured endothelium and other platelets. In secondary hemostasis, it binds to factor FVIII and protects it from early clearance.
How is von Willebrand factor released?
von Willebrand factor (vWF) circulates in the blood in two distinct compartments. One, plasma vWF, is synthesized and released from endothelial cells; the second, synthesized by megakaryocytes, circulates in platelets primarily stored in the alpha granules.
What activates tissue factor?
Tissue factor (TF) is a transmembrane receptor for Factor VII/VIIa (FVII/VIIa). It is constitutively expressed by cells surrounding blood vessels. The endothelium physically separates this potent “activator” from its circulating ligand FVII/FVIIa and prevents inappropriate activation of the clotting cascade.
What is the difference between vasopressin and desmopressin?
Desmopressin (1-deamino-8-O-arginine-vasopressin, DDAVP) is a synthetic analogue of arginine vasopressin. It has 10 times the antidiuretic action of vasopressin, but 1500 times less vasoconstrictor action.
What DDAVP stand for?
Desmopressin (also known as DDAVP, which stands for 1-deamino-8-D-arginine vasopressin) is a synthetic medicine that boosts levels of factor VIII (FVIII) and von Willebrand factor (VWF) to prevent or control bleeding.
What secretes von Willebrand?
von Willebrand factor (vWF) and platelets are the key components of blood that initiate clots. vWF is a large multimeric glycoprotein. It is produced by endothelial cells, stored in the form of ultralarge (UL) vWF multimers in Weibel–Palade bodies, then secreted by exocytosis of the Weibel–Palade bodies (6, 7).