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. 鈥淚f a person has
atherosclerosis in one artery, he or she may well have it in others. So, often
those replacement arteries are not available,鈥� 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.
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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. 鈥淚t may be a
breakthrough, but it will take years to find out how well it works.鈥�
