Though Borschel and Brown are plastic surgeons, perhaps the widest applications for this technique are in cardiac surgery. For example, patients undergoing coronary artery bypass might benefit from tissue engineered donor vessels. For people receiving bypass surgery or a tissue transfer after an injury, surgeons often harvest blood vessels from the leg, sternum or arm. But taking tissue from these areas can cause problems in that location.
Donor tissue is not an option because the body would reject the foreign cells. The engineered tissue would be injected with the host's own cells, reducing the risk of rejection.
In this study, researchers harvested the iliac (groin) grafts from rats. They then stripped this tissue of its cells using a detergent solution. The acellular tissue was injected with endothelial cells from genetically identical rats before being grafted into the rat's femoral artery. A control group of rats received grafts of acellular tissue not re-engineered with the new rat's cells.
The resulting blood vessels were monitored every 48 hours and examined closely after four weeks and again at three months. At four weeks, eight of the nine recellularized grafts remained open and functioning, while three of the five acellularized control grafts had clotted. One group of recellularized grafts was viable at three months. The recellularized grafts also demonstrated structural characteristics similar to normal vessels.
"This is a very close collaboration between three areas: clinical, engineering and basic biology," says study co-author Robert G. Dennis, Ph.D., assistant professor of biomedical engineering at U-M.
Researchers are now looking at ways to use this technology. In one application, researchers have created a biochamber that contracts like a heart. The pressure stimulates the endothelial cells into the chamber, helping new cells to grow and tak
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Contact: Nicole Fawcett
nfawcett@umich.edu
734-764-2220
University of Michigan Health System
22-Oct-2003