Patients with coronary heart disease may one day have the treatment option of generating new arteries.
Researchers at Duke University Medical Center published a report last week stating that they had bioengineered durable blood vessels using blood cells from elderly cardiac disease patients—those most in need of better artery graft options.
Currently, about 50 percent of coronary artery bypass grafts fail within 10 years of completed procedures due to infections or the old age of vessels used for transplants.
The growth of the vessels from patients’ own blood cells would facilitate the replacement of arteries with more dependable grafts.
The researchers—led by Laura Niklason, associate professor of biomedical engineering—grew the arteries by inducing growth of cells from the saphenous leg veins, which are currently used in bypass surgery.
Niklason said the idea to culture replacement blood vessels from elderly patients’ cells first came to mind when she was a resident of anesthesiology at Massachusetts General Hospital.
“During my residency I can always remember doctors looking in all kinds of areas for strong, healthy vessels,” said Niklason. “I concluded it would be very beneficial to grow vessels independently.”
Niklason first grew and implanted vessels in pigs in 1999, but when she turned to humans, she had to face the challenge of the cells’ short life cycles caused by a lack of telomerase—an enzyme that prevents cell shortening following cell division.
She joined forces with Christopher Counter, associate professor of pharmacology and cancer biology, and the researchers induced telomerase expression in the cells, which prolonged the cells’ life cycles.
Although the created vessels withstood simulation blood pulses and produced improved levels of collagen to support vessel structure, Niklason said the arteries only reached about half the strength that would be needed for actual implantation.
She added that cells were immersed in salt solutions during operations for patient safety purposes, which likely led to the degradation of cells.
“Strength levels will be altered in later runs by changing conditions to better support collagen production,” Niklason said.
Before eventually having a refined version of the treatment approved by the Food and Drug Administration, risks for unhealthy tumor growth must be further assessed and certain conditions changed for cell growth.
Though research is ongoing, Niklason hopes the procedure can be implemented in several years.
“Niklason’s discovery is exciting in that it gives you a great chance to make new grafts to replace other major conduits that provide very little success,” said Christopher Kontos, assistant professor of medicine in cardiology.
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