ARLINGTON, Va., March 21, 2002 --- Biomedical engineers at the University of California, San Diego, have received a patent for an experimental gene therapy to prevent blood vessels from reclosing after balloon angioplasty.

In animal trials, the therapy cut in half the incidence of clogged arteries.

"In some sense, the procedure of angioplasty is tailor-made for delivering gene therapy," said Shu Chien, M.D., Ph.D., professor of bioengineering and medicine and director of the Whitaker Institute of Biomedical Engineering at UCSD. "The therapeutic genes can be given through the catheter during angioplasty, so no additional invasive procedures are required."

Angioplasty is a common treatment for opening clogged arteries. A catheter with a balloon at the tip is inserted in the artery and the balloon is inflated to press against the artery wall and open the vessel. A side effect of the treatment can be damage to the blood vessel wall, which can trigger a series of events that cause the wall to thicken and attract a new buildup of plaque. One-third of angioplasty patients experience a reclogging of the arteries (restenosis) in the weeks or months following the procedure.

Chien has identified a protein called RAS that is critical to this reclogging process. His gene therapy uses RasN17, which blocks the function of RAS. RasN17 is delivered to the site of the angioplasty through the same catheter that is used to open the artery.

Chien's group has tested the therapy in pigs, which have a circulatory system similar to that of humans. One group of pigs was treated with RasN17, another group was not. The group that received the gene therapy had 56 percent less artery wall thickening than the pigs that did not receive the gene.

Results of the animal experiments have been published in the Journal of Surgical Research.

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Frank Blanchard (703) 528-2430