Nav: Home

An injectable UW polymer could keep soldiers, trauma patients from bleeding to death

March 10, 2015

Most military battlefield casualties die before reaching a surgical hospital. Of those soldiers who might potentially survive, most die from uncontrolled bleeding.

In some cases, there's not much medics can do -- a tourniquet won't stop bleeding from a chest wound, and clotting treatments that require refrigerated or frozen blood products aren't always available in the field.

That's why University of Washington researchers have developed a new injectable polymer that strengthens blood clots, called PolySTAT. Administered in a simple shot, the polymer finds any unseen or internal injuries and starts working immediately.

The new polymer, described in a paper featured on the cover of the March 4 issue of Science Translational Medicine, could become a first line of defense in everything from battlefield injuries to rural car accidents to search and rescue missions deep in the mountains. It has been tested in rats, and researchers say it could reach human trials in five years.

In the initial study with rats, 100 percent of animals injected with PolySTAT survived a typically-lethal injury to the femoral artery. Only 20 percent of rats treated with a natural protein that helps blood clot survived.

"Most of the patients who die from bleeding die quickly," said co-author Dr. Nathan White, an assistant professor of emergency medicine who teamed with UW bioengineers and chemical engineers to develop the macromolecule.

"This is something you could potentially put in a syringe inside a backpack and give right away to reduce blood loss and keep people alive long enough to make it to medical care," he said.

The UW team was inspired by factor XIII, a natural protein found in the body that helps strengthen blood clots.

Normally after an injury, platelets in the blood begin to congregate at the wound and form an initial barrier. Then a network of specialized fibers -- called fibrin -- start weaving themselves throughout the clot to reinforce it.

If that scaffolding can't withstand the pressure of blood pushing against it, the clot breaks apart and the patient keeps bleeding.

Both PolySTAT and factor XIII strengthen clots by binding fibrin strands together and adding "cross-links" that reinforce the latticework of that natural bandage.

"It's like the difference between twisting two ropes together and weaving a net," said co-author Suzie Pun, the UW's Robert J. Rushmer Professor of Bioengineering. "The cross-linked net is much stronger."

But the synthetic PolySTAT offers greater protection against natural enzymes that dissolve blood clots. Those help during the healing process, but they work against doctors trying to keep patients from bleeding to death.

The enzymes, which cut fibrin strands, don't target the synthetic PolySTAT bonds that are now integrated into the clot. That helps keep the blood clots intact in the critical hours after an injury.

"We were really testing how robust the clots were that formed," said lead author Leslie Chan, a UW doctoral student in bioengineering. "The animals injected with PolySTAT bled much less, and 100 percent of them lived."

The synthetic polymer offers other advantages over conventional hemorrhaging treatments, said White, who also treats trauma patients at Harborview Medical Center.

Blood products are expensive, need careful storage, and they can grow bacteria or carry infectious diseases, he said. Plus, the hundreds of proteins introduced into a patient's body during a transfusion can have unintended consequences.

After a traumatic injury, the body also begins to lose a protein that's critical to forming fibrin. Once those levels drop below a certain threshold, existing treatments stop working and patients are more likely to die.

In the study, researchers found PolySTAT worked to strengthen clots even in cases where those fibrin building blocks were critically low.

The UW team also used a highly specific peptide that only binds to fibrin at the wound site. It does not bind to a precursor of fibrin that circulates throughout the body. That means PolySTAT shouldn't form dangerous clots that can lead to a stroke or embolism.

Though the polymer's initial safety profile looks promising, researchers said, next steps include testing on larger animals and additional screening to find out if it binds to any other unintended substances. They also plan to investigate its potential for treating hemophilia and for integration into bandages.
-end-
Funding came from the National Institutes of Health and its National Center for Advancing Translational Science, the UW Institute of Translational Health Sciences, the Washington Research Foundation, an NIH-supported UW Bioengineering Cardiovascular Training Grant and discretionary funds from private donations.

For more information, contact Pun at spun@uw.edu or White at whiten4@uw.edu.

University of Washington

Related Protein Articles:

A direct protein-to-protein binding couples cell survival to cell proliferation
The regulators of apoptosis watch over cell replication and the decision to enter the cell cycle.
A protein that controls inflammation
A study by the research team of Prof. Geert van Loo (VIB-UGent Center for Inflammation Research) has unraveled a critical molecular mechanism behind autoimmune and inflammatory diseases such as rheumatoid arthritis, Crohn's disease, and psoriasis.
Resurrecting ancient protein partners reveals origin of protein regulation
After reconstructing the ancient forms of two cellular proteins, scientists discovered the earliest known instance of a complex form of protein regulation.
Sensing protein wellbeing
The folding state of the proteins in live cells often reflect the cell's general health.
Protein injections in medicine
One day, medical compounds could be introduced into cells with the help of bacterial toxins.
Discovery of an unusual protein
Scientists from Bremen discover an unusual protein playing a significant role in the Earth's nitrogen cycle.
Protein aggregation: Protein assemblies relevant not only for neurodegenerative disease
Amyloid fibrils play a crucial role in neurodegenerative illnesses. Scientists from Heinrich Heine University Düsseldorf (HHU) and Forschungszentrum Jülich have now been able to use cryo-electron microscopy (cryo-EM) to decode the spatial structure of the fibrils that are formed from PI3K SH3 domains - an important model system for research.
Old protein, new tricks: UMD connects a protein to antibody immunity for the first time
How can a protein be a major contributor in the development of birth defects, and also hold the potential to provide symptom relief from autoimmune diseases like lupus?
Infection-fighting protein also senses protein misfolding in non-infected cells
Researchers at the University of Toronto have uncovered an immune mechanism by which host cells combat bacterial infection, and at the same time found that a protein crucial to that process can sense and respond to misfolded proteins in all mammalian cells.
Quorn protein builds muscle better than milk protein
A study from the University of Exeter has found that mycoprotein, the protein-rich food source that is unique to Quorn products, stimulates post-exercise muscle building to a greater extent than milk protein.
More Protein News and Protein Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.