Platelets can quickly stanch the bleeding from a cut in your finger, but the hemorrhaging caused by a car crash or a battlefield injury might overwhelm the blood-clotting abilities of these cell fragments. Now, researchers report that they have designed a potential helper for such situations, a synthetic platelet that they show can curtail blood loss in animals.
After an injury, platelets stick to the walls of damaged vessels, to each other, and to clotting proteins, forming a plug. Platelet transfusions can boost clotting in trauma patients, wounded soldiers, and people with low platelet counts because of disease or cancer treatment. But platelets obtained from donated blood have several drawbacks, including a shelf life of only 5 days–versus 6 weeks for red blood cells–and a risk of bacterial infections.
Researchers have devised replacement platelets, such as red blood cells outfitted with a three-amino-acid sequence called RGD that natural platelets latch on to, thus potentially inducing a clot. So far, none of these alternatives has reached the emergency room. “If there was a suitable platelet substitute, that would be a tremendous achievement for clinical medicine,” says hematologist Marcel Levi of the University of Amsterdam in the Netherlands.
Platelet helper. Artificial platelets (green) crowd a blood clot.
CREDIT: J. BERTRAM ET AL., SCIENCE TRANSLATIONAL MEDICINE