A Duke University Medical Center researcher, using a novel "bioreactor" system that mimics the fetal environment, has used cells taken from adult pigs' arteries to grow blood vessels that look and act like the real thing. When implanted back into the same animals, the arteries functioned much like native vessels, said Dr. Laura Niklason, who published the results of her team's experiments in the April 16 issue of the journal Science.
While there are many biological and technical hurdles to be overcome before such an approach could be considered for use in humans, such as to treat heart disease, the researchers said this development represents a significant advance in the field of tissue engineering.
"We are very excited that after many years, we have produced a bio-engineered tissue that appears functional in animals," said Niklason, an anesthesiologist and bioengineer at Duke.
The engineered vessels, which were grown in a bioreactor that provided nutrients and pulsed the growing vessels much like a heart would, were as strong as native vessels, could hold a suture without ripping and responded to drugs in much the same manner as native vessels would.
The series of experiments was funded by two grants from the National Institutes of Health and one from the Foundation for Anesthesia Education and Research. "While we still have much work to accomplish before moving into human studies, these results not only demonstrated the feasibility of culturing autologous arteries, but also that the pulsatile approach was very effective," Niklason said.
To create the arteries, Niklason fashioned a tube from a thin sheet of a biodegradable polymer which, like a sponge, is 97 percent air. Smooth muscle cells were collected from the animal arteries and were impregnated throughout the polymer tube. Once placed within the bioreactor, the tube was bathed with similar nutrients found in native vessels.