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时间:2019-03-08 01:10:03166网络整理admin

By Matt Walker DAMAGED blood vessels could soon be replaced with artificial tubes built from a polymer tailor-made by bacteria. Each year, over half a million people worldwide require surgery to replace blocked vessels with healthier tubes taken from elsewhere in the body. But sometimes there are not enough vessels to go around. “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,” says David Tirrell of the California Institute of Technology in Pasadena. Up to a third of transplants also fail within five years, he says. Tirrell and colleagues have devised a way to build artificial blood vessels that could be implanted in place of a natural vein or artery. The researchers genetically engineered bacteria to produce a polymer similar to elastin, the stretchy protein that lines the walls of blood vessels. This similarity to a real proteins is the key to the biomaterial. The idea is that the protein substitute will be woven to form the basic structure of a blood vessel. Once implanted, layers of endothelial blood vessel cells should grow on the polymer matrix. Cells from a patient could even be grown on the artificial vessels before implantation. Other teams are working on similar ways of creating artificial vessels (This Week, 27 February, p 10). Tirrell hopes to test the polymer matrix on animals within a year. But Colin Caro, a physiologist at Imperial College, London, says much will depend on the elastic properties of the polymer and its effect on blood flow. “It may be a breakthrough,