Artificial Platelets Catalyze Clotting
Researchers reported they have designed a synthetic platelet that can potentially help in fatal hemorrhaging. Naturally, platelets can quickly stop the bleeding from a small cut, but the hemorrhaging caused by a car crash or a battlefield wound might overwhelm the cell fragments. After an injury, platelets attach to the walls of the damaged vessels and to each other creating a plug. Platelet transfusions can increase clotting in wounded patients, wounded soldiers, and patients with low platelet counts. However, donated platelets have its limitations. It has a shelf life of only 5 days--versus 6 weeks for red blood cells--and a risk of bacterial infections. Six years ago, James Bertram, then a graduate student at Yale University, started developing a substitute for platelets. His design used spheres “about one-tenth the diameter of a platelet and composed of the same biodegradable polyester used in absorbable sutures.” The spheres carry molecules of polyethylene glycol with RGD (3-sequence amino acid). The idea is that the spheres will attach to the platelets and help create a clot. It was tested on rats that had a cut in a large vessel in their hind leg. An injection of the synthetic platelets, given right after the cut, reduced the bleeding time by 23%.The team now wants to use the synthetic platelets in larger animals, such as pigs, that are more similar to humans. Some experts see the results as promising but some say it isn’t. John Hess, a hematologist at the University of Maryland School of Medicine in Baltimore, argued that patients with severe bleeding are losing large amounts of platelets, so an approach that relies on recruiting platelets might not work.
M. Leslie, “ Artificial Platelets Catalyze Clotting,” Science, 12/16/2009.
http://news.sciencemag.org/sciencenow/2009/12/16-02.html
, [02/17/2010].
0 comments:
Post a Comment