ANN ARBOR---A spongy plastic material impregnated with two kinds of growth factor has been shown to encourage the formation of healthy new blood vessels in living rats, according to a tissue engineering research team at the University of Michigan.
The ability to grow new blood vessels in a controlled fashion could lead to better treatments for coronary artery disease, to speed wound healing, or to help diabetic patients who are suffering from peripheral vascular disease.
"This new approach allows us to deliver a controlled dose of growth factors to a specific tissue," said David J. Mooney, a professor of biologic and materials science in U-M's College of Engineering and School of Dentistry. "To grow a replacement tissue cell by cell, you need a combination of growth factors delivered in the right sequence at the proper time and in the right place. Just injecting a large amount of it with a needle doesn't work."
Coronary artery disease occurs when blocked vessels fail to deliver enough blood and oxygen to the heart muscle itself. The coronary bypass operation, which is performed nearly 3 million times per year in the United States, involves removing an artery or vein from one part of the body and then stitching it onto the threatened area of the heart. The ribcage must be cut open, and the heart's beating is stopped during the procedure.
However, this polymer may be able to grow new vessels on site with much less invasive surgery.
Two naturally-occurring growth factor chemicals are key to the formation of proper blood vessels, VEGF, the Vascular Endothelial Growth Factor, and PDGF, the Platelet-Derived Growth Factor. But simply basting an area of tissue with both chemicals does not result in satisfactory angiogenesis, or vessel development. The vessels may form, but they end up falling apart because they are not constructed properly. And if VEGF levels fall too low, vessels are even subject to "pruning and remodel
Contact: Colleen Newvine
University of Michigan