The February 12, 2007, issue of the Wall Street Journal (page A1), Ron Winslow highlights the pioneering work of McGowan Institute scientist Stephen Badylak, DVM, PhD, MD. In the 1980s, Dr. Badylak identified the importance of extracellular matrix, which scientists say harbors signaling molecules that help direct the development of cells into tissue, during an experiment in which he used a portion of a dog's intestine to fashion a makeshift aorta for its heart. Not only was the dog's tail wagging the morning after the surgery, but months later, an examination revealed that the transplanted intestine part had morphed into a vessel that looked much like an aorta. Somehow, it had sensed where it was in the body and had remodeled itself to take on the structural traits of an aorta. There was hardly any scarring.
Subsequent research has helped Dr. Badylak and his colleagues understand the mechanisms behind this remarkable tissue remodeling. That research to a layer of intestinal lining called the submucosa, a form of extracellular matrix. Dr. Badylak's team found that extracting the submucosa from the intestine and putting patches of it at injury sites triggered a novel healing response: As the implanted matrix material broke down, healthy living tissue, not scar tissue, repaired the damage. Matrix from bladders, liver and other organs induced a similar reaction.
The matrix, considered a medical device by the Food and Drug Administration, is now commonly used in rotator-cuff procedures and Achilles-tendon repairs. Other orthopedic-products companies have developed similar technology that they market as an alternative or adjunct to conventional orthopedic procedures. Over 1,000,000 patients world-wide have benefited by some form of this matrix.
In 2005 a 68-year-old hobby shop owner accidentally lopped about three-eighths of an inch off the top of his middle finger on the propeller of a model airplane. A novel treatment was devised using a powdered version of the extracellular matrix which was applied to the end of the severed finger every other day for 10 days; in four weeks, the wound was healed. In four months the finger resembled the original finger prior to the accident.
Using a similar strategy, five soldiers at a Texas military base are about to participate in a remarkable test to see if they can regrow portions of fingers they lost in the war in Iraq.
Doctors plan to treat them with a powdered version of the extracellular matrix, harvested from pig bladders. The experimental procedure is expected to begin late this spring; surgeons will reopen the skin around what's left of the soldiers' fingers. Matrix will be applied three times a week for at least two weeks. During each application, researchers will look for new tissue and for complications. If no problems arise in the first five soldiers, the doctors will treat five more, and then assess the procedure thoroughly. They hope to know within a couple of months after treatment begins whether it works.
Illustration: This salamander, pictured in an undated photo, has been made to grow an extra arm out of its natural left arm as the result of an experimental procedure. Salamanders are being studied to find out how they naturally regrow limbs that have been chopped off. –Pittsburgh Post-Gazette
UPMC News Bureau (02/12/07)
Pittsburgh Post-Gazette (02/21/07)