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FYI Research: |
Inside your body, platelets rush to the site of an injury and activate, sticking together to clot your blood. But take these cells and try to store them, and they lose some of their power. Once put back inside the body, stored liquid platelets can rejuvenate in a few hours and help prevent bleeding. But they’re not fast enough or reliable enough to stop acute bleeding from a gunshot wound or other injury. A new Carolina startup company, created with the help of the University's Office of Technology Development, is well on its way to a solution-—a method of freeze-drying platelets that preserves their function. Tom Fischer, associate professor of pathology and lab medicine, and other researchers behind Hemocellular Therapeutics have developed freeze-dried platelets that have been shown in more than 250 studies in rabbits, dogs, and pigs to stop acute bleeding. The researchers plan to have a product ready for testing in humans within 18 months. The key to their technology, Fischer said, is a process called molecular cross-linking, which involves adding a molecule of paraformaldehyde to the cells. “The molecule has a reactive chemical group on each end of it. So it’s got two active parts, and it will sit down and join two proteins together on the surface of the platelet so that they are then stabilized,” he said. “We end up with a net-like structure all over the surface of the cell that gives it a little strength so that it won’t rupture when frozen due to ice expansion.” This structure preserves the platelets so they can survive the freeze-drying process. Paraformaldehyde is a reactive derivative of formaldehyde. That sounds a bit scary--formaldehyde in a blood product? But, Fischer said, paraformaldehyde doesn’t “persist in the product.” Any chemical that doesn’t react with the cells is washed away before freeze-drying. For many years, scientists have been “fixing” cells with paraformaldehyde to preserve cell structure for viewing under a microscope. But the fixing usually destroys the function of the cells. Hemocellular’s technology preserves the cells and their function. Marjorie Read, emeritus professor of pathology, is the “real innovator” behind this technology, Fischer said. “Doctor Read’s brainstorm was finding the sweet spot--the point where the platelets were cross-linked just enough to preserve them but their function was not destroyed,” he said. “Her genius was to first ask the question ‘Well, can we do this?’ And then she went in the lab and did it.” Read achieved that result in 1992. Since Read’s retirement, Fischer has continued the work. “So 11 years later, we’ve shown that not only does the cross-linking work, but the lyophilized [freeze-dried] platelets can retain function to stop bleeding in animals, and can be stored for a long period of time,” Fischer said. The paraformaldehyde also sterilizes the platelets, reducing risk of infection. Other research groups have done work on methods of freeze-drying platelets, but Hemocellular’s technology is the closest to becoming a usable product. Researchers at the University of California, Davis, for example, have been preserving platelets before freeze-drying by adding a sugar called trehalose. But these platelets have not yet been shown to retain their function, Fischer said. Now Fischer and Arthur Bode, cofounder of Hemocellular and a pathology professor at East Carolina University, are working to meet FDA requirements so the product can progress to the next step—testing in human clinical trials. “We’re working on getting every little detail worked out,” Fischer said, “to make sure we have a very consistent manufacturing process.” For information about reporting inventions of your own, contact the Office of Technology Development at 966-3929 or visit their web site at http://research.unc.edu/otd. |