A modified gene and an antiviral drug may help prevent reblockage of arteries in heart patients who have had balloon angioplasty, researchers reported Friday.
In a study at the University of Michigan, researchers experimenting with pigs showed that blockages after angioplasty could be reduced by putting into blood vessel cells an altered gene that made new blood vessel cells sensitive to the antiviral drug ganciclovir.Dr. Gary J. Nabel of the University of Michigan, one of the lead authors of the study published in the journal Science, said the gene causes the formation of what he calls "suicide enzyme" in the target cells.
Nabel said that the gene technique offers promise for correcting a serious problem, called restenosis, for heart patients treated for artery blockage with balloon angioplasty.
In balloon angioplasty therapy, a catheter is threaded through blood vessels to the site of a blockage. A balloon-like tube is then inflated, pushing the material forming the blockage away from the center of the vessel and allowing better blood flow.
But the process also injures the vessel wall, Nabel said. The body responds by growing new cells to replace those that were injured.
In about 40 percent of the cases, too many cells are grown and the result is that the artery is again blocked. Researchers have been trying for years to find a way to prevent this cell overgrowth.
Nabel said the gene and drug therapy starts a cascade effect that helps keep arteries open.
"The nice thing about this strategy is that no other cells of the body are subjected to the toxic form of the drug," Nabel said. He said the technique does affect "bystander cells" that are dividing inappropriately, but it leaves normal cells alone.