Stories about: blood clots

“Shapeshifter” that regulates blood clotting is visually captured for the first time

GIF of VWF, which regulates blood clotting, elongating and relaxing on loop
A single molecule of von Willebrand factor is visually captured, as it elongates and relaxes in response to blood flow conditions, for the very first time. Credit: Springer/Wong labs (Boston Children’s Hospital and Harvard Medical School)

We are normally born with a highly sophisticated array of molecules that act as “sentries,” constantly scanning our bodies for injuries such as cuts and bruises. One such molecular sentry, known as von Willebrand factor (VWF), plays a critical role in our body’s ability to stop bleeding.

To prevent hemorrhage or life-threatening blood clots, VWF must strike a delicate balance between clotting too little or too much. Researchers have long suspected that the mechanical forces and shear stress of blood flow could be closely-related to VWF’s function.

“In some ways, like in the movie Star Wars, VWF may be considered a Jedi knight in our body that can use ‘the force’ to guard the bloodstream,” says Timothy Springer, PhD, of Boston Children’s Hospital and Harvard Medical School (HMS).

It has not been possible to witness exactly how VWF senses and harnesses these mechanical forces — until now.

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Putting the squeeze on blood clots to stop a stroke

Blood should flow through an artery like water through a hose. The stress of a blockage can encourage clots to form, potentially resulting in a heart attack or stroke. Donald Ingber thinks the same forces could be used to help dissolve clots. (Beth Kingery/Flickr)

Grab a garden hose. Put your thumb over the end, but not all the way, and turn the water on. What happens? The water coming out of the hose gets squeezed as it tries to push past your thumb, putting a lot of force on the molecules in the water and making a big spray.

Now do the same thing with an artery: Partially block it with a clot and let blood flow through it. In this case, the force you’ve created in the artery could be lethal—creating fertile ground for blood clots that could lead to a stroke or heart attack.

But what if that combination of force and pressure could be used to stop something like a stroke instead? What if it could release a clot-dissolving drug on the spot? Donald Ingber, MD, PhD, a member of Boston Children’s Hospital’s Vascular Biology Program, had wondered that for many years. To find out, Ingber, who also directs the Wyss Institute for Biologically Inspired Engineering at Harvard, had his team start with a simple question: How do clots form?

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