Using arterial cells from a two-year-old child, the Duke team reported in 2003 that when the hTERT gene was introduced into smooth muscle cells, key components of an artery, the life span of the cells was extended long enough to form arteries in the laboratory.
In the latest experiments, the researchers took cells from the saphenous vein of four men between the ages of 47 and 74 who were undergoing coronary artery bypass surgery. The saphenous vein is located in the lower leg and is often used to bypass blockages in arteries around the heart. The team isolated smooth muscle and endothelial cells, grew them in culture and treated them with hTERT.
To create the new arteries, the researchers fashioned a tube from a thin sheet of a biodegradable polymer that was 97 percent air, much like a sponge. The treated smooth muscle cells were then impregnated throughout the polymer tube. The bioreactor pulsed a vitamin and nutrient solution through and around the tube, approximating as closely as possible the conditions that would exist in nature.
Once the smooth muscle cells proliferated and filled all the spaces within the dissolving polymer scaffolding, the researchers added endothelial cells, which line the interior of blood vessels, to complete the artery. Vessels grew for up to seven weeks.
"While the resulting vessels looked like natural vessels, they were not strong enough to be implanted into humans successfully," Niklason said. "However, th
Contact: Richard Merritt
Duke University Medical Center