Blood Clot Glue
March Meeting 2010
WASHINGTON, D.C. — Your blood is loaded with a gluey molecule called von Willebrand Factor (vWF). Normally, this gigantic protein (the second-largest in our body) tumbles about freely through the bloodstream. Cut your finger, and it becomes sticky, attaching to the site of injury and causing platelets to clump together to start the process of plugging the wound with a clot. Charles Sing and Alfredo Alexander-Katz of the Massachusetts Institute of Technology have discovered the secret to this stickiness, a principle that could be exploited to create artificial compounds that could sense leaks and seal leaky pipes from the inside. After injury occurs, the vWF stretches out, exposing sticky bits usually hidden on the inside.
This shape change happens because injury causes the blood vessels to constrict, which changes the flow inside and creates forces that, from the molecule's perspective, pull the ends in opposite directions. "It's triggered by mechanical forces, in this case by flows," said Alexander-Katz. The finding may also help researchers to better understand medical conditions such as von Willebrand Disease—in which vWF is defective or deficient and excess bleeding occurs—and thrombotic thrombocytopenic purpura, a life-threatening condition in which the molecule works too well and forms clots that travel through the circulatory system.
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