These grafts worked well in animals, but testing in humans is still a few years off
WEDNESDAY, April 7 (HealthDay News) -- Blood vessels engineered from laboratory-grown stem cells have worked well in animals, researchers say, and might someday replace the synthetic products now in use.
When needed for procedures such as bypass surgery, blood vessels now are usually taken from the person's body. Artificial grafts are used about 40 percent of the time, but those grafts are far from perfect, explained Stephen E. McIlhenny, a postdoctoral researcher at Thomas Jefferson University Hospital in Philadelphia. He was scheduled to report on the advance at an American Heart Association conference Thursday in San Francisco.
Artificial vessels "never become arterial-like," McIlhenny said. "They have been shown to close readily within one to three years, and they never contract or otherwise respond to changes in blood pressure."
By contrast, the tissue-engineered blood vessels that have been successfully tested in animals do behave more like the real thing because "they contain components of the natural artery," McIlhenny said.
The process of building such blood vessels starts with the extraction of human fat tissue from the region around the belly button, he said. "We isolate the cellular fraction of the tissue and further purify it," McIlhenny explained. "Then we differentiate them by cellular and mechanical means. These stem cells acquire the markers of the endothelial cells that line the interior of arteries."
The cells then are grown on a scaffold consisting of protein. The result is "a biological conduit that is more biomedical in nature than synthetic material," McIlhenny said.
The work done by the Thomas Jefferson researchers involved 10 rabbits. Five had stem-cell-derived grafts inserted in the aorta, the main heart artery, and five had grafts of the bare protein scaffold. After eight week
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