Thursday, August 25, 2016

In Combat and Car Accidents, Nanoparticles Could Fight Internal Bleeding

Injury is the number one cause of death in Americans ages 1-44. Resulting from violence and accidents, injuries claim nearly 200,000 lives per year in the United States alone. A team of researchers from the University of Maryland, Baltimore County is fighting back with a simple, nanoparticle-based technology to reduce blood loss from internal injuries.

Nanoparticles (green) help form clots in an injured liver. The researchers added color to the scanning electron microscopy image after it was taken.
Image Credit: Andrew Shoffstall, Ph.D
Whether injuries are sustained in car accidents or combat, the key to saving a life and improving outcomes is often to stop the bleeding quickly. You can tackle external bleeding with pressure, stiches, and other methods, but internal bleeding is a different story. Surgery is really the only intervention that stops internal bleeding.

Earlier this week a research team led by Erin Lavik announced progress on a completely different kind of treatment for internal bleeding, one that could be administered in the field immediately, even when the extent and location of the internal injuries are unknown. This work was presented at the 252nd National Meeting and Exposition of the American Chemical Society.

When a blood vessel is damaged and the body starts bleeding, platelets in the blood stream are “activated” and they clump together at the injury site and form clots. This is the first stage in the healing process and is the body’s method of stopping blood loss. Often this response is enough, but sometimes blood loss can outpace clotting and cause death.

Lavik and her team designed nanoparticles that can be injected into the bloodstream to speed up clotting. These particles travel through the body and bind to activated platelets. They act as a kind of bridge between platelets, helping them connect and therefore clot faster. Made out of the same material as degradable sutures, the nanoparticles don’t stay in the blood stream very long (maybe a couple of minutes) unless they bind to activated platelets. Nanoparticles in clots stay in the body longer, but degrade over time as the wound heals.

The dream is that medics and emergency responders could carry this technology into the field and administer the nanoparticles as soon as possible after a traumatic injury. For victims of IEDs, car accidents, and other circumstances that cause multiple traumas, this could be huge. Because the nanoparticles aren’t directed at a certain part of the body, they promote healing anywhere platelets are activated. In other words, you can treat injuries that you don’t even know about.

This technology hasn’t been tested in humans yet, but experiments on the lab bench and in rodents indicate that it works. Blood clots form faster at injury sites when the nanoparticles are present. An experiment on rodents with a femoral artery wound showed the bleeding time cut in half when they were injected with the nanoparticles as compared to a control group injected with saline. Another test, this one involving a liver wound, showed an increased survival rate among rodents injected with the nanoparticles.

Lavik never set out to develop a technology to stop internal bleeding. A professor of chemical, biochemical, and environmental engineering, her primary area of interest is the central nervous system. What started as a 6-month project to explore the impact of hemorrhaging on spinal cord injuries and brain injuries turned into a much deeper pursuit when her team realized there were no real tools to stop internal bleeding other than surgery.

Now, more than six years later, her team is just starting to explore whether the technique they developed is effective in slowing and stopping blood loss from spinal cord injuries and brain injuries. If so, perhaps they will be able to finally test the question that started it all.

Although their approach is direct, the devil is in the subtleties. For example, tests showed that early versions of the nanoparticles triggered immune system responses. Of course you don’t want to treat an injury with something that the body might fight, so the team had to find a way around this. Another important consideration is whether the nanoparticles can lead to clotting at non-injury sites. So far there is no evidence of this, but it’s one of many safety concerns that needs to be thoroughly studied.

Will this work in humans? Is it safe? Early evidence is promising, but getting to the point of human trials will require a lot more tests, planning, and paperwork. If the results continue to be promising, though, it could revolutionize trauma care within 5-10 years.

Kendra Redmond

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