The role of von Willebrand factor in thrombus formation

Von Willebrand Factor (vWF) is a chemical factor that is produced by either the the endothelium or megakaryocytes. It is one of the factors involved in platelet function, thus very important in the blood clotting process of the body. It is usually activated or released in response to exposure to collagen and its role in platelet plug formation is to link platelets to collagen. Absence of vWF will cause prolonged bleeding.

The effects of shear strain on  vWF is considered in this article. vWF is a very large blood glycoprotein which ranges in size from approx. 500kDa to 20,000kDa.  It plays a crucial role in haemostasis and thrombosis by acting as a bridge between platelets and the injured endothelium under conditions of high shear stress. Large oligomers are more efficient at doing this as proven by research, it doesn't work well when broken up into many strands or chains. And, it is said that patients with Ventricular Assist Device (VAD) develop Type IIA acquired von Willebrand disease (AVWD), which is characterized by a loss of high molecular weight (HMW) oligomers. Patients suffer from bleeds, especially gastrointestinal (GI) bleeding. It is hypothesized that increased shear strain on blood will cause greater loss of HMW oligomers, contributing to AVWD.

I found this article interesting due to the fact that during the summer, I was doing some research with my professor learning the effect the shear stress in patients with ventricular assist device upon blood damage which causes acquired von Willebrand syndrome. I hope you will like the article as much as I did as it is fascinating to know that such a small factor in the platelet function can cause such a huge influence on the patients' blood clotting process and think how does it affect patients with VAD? Food for thought. Plus, we will be learning about platelets and coagulation in Chapter 16.

URL:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702526/