ANAHEIM, Calif., March 24 -- A new protein-like polymer that supports the growth of endothelial cells and could be used for blood vessel replacement has been designed by researchers at the California Institute of Technology.
Each year, more than 500,000 people undergo vein or artery replacement therapy, often due to atherosclerosis, a form of hardening of the arteries. The research was presented here today during the week-long national meeting of the American Chemical Society, the world's largest scientific society.
The new material is expected to aid patients who cannot supply their own replacement veins. Typically, replacement of damaged veins or arteries is done by using another blood vessel from elsewhere in the person's body, generally a saphenous vein from the legs or the internal mammary artery that runs along the inside of the breast bone. CalTech's David Tirrell, Ph.D., says, "If a person has atherosclerosis in one artery, he or she may well have it in others. So, often those replacement arteries are not available." Even when they can be used, he points out, success rates are only about 70 percent after five years and even lower with current synthetic polymers used for vascular replacement.
The new polymer, which Tirrell describes as a biomaterial, is "closer to proteins, which gives us more flexibility with respect to the kinds of cellular interactions and mechanical properties we can achieve." Genetic engineering was used to produce analogues of the polymer's key component, elastin, a protein similar to collagen and an essential part of elastic fibers in mammals. Tirrell also credits University of Minnesota researcher Dan Urry with much of the early groundbreaking work on biomedical uses of elastin.
The polymer would be implanted in place of the diseased portion of the artery or vein, says Tirrell, and serve as a matrix within which the body could form its own layer of endothelial cells, which normally line a blood vessel. The cells also could be introduced to the polymer before implantation, he notes. The next step for the new polymer is testing it in laboratory animals, which Tirrell says could be done within the next year or so.
A nonprofit organization with a membership of nearly 159,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
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