Busting blood clots with a nanoparticle
Experimental drug delivery may improve heart attack treatment
By Nathan Seppa
ORLANDO, Fla. — Nanosized gobs containing a blood clot–dissolving drug can seek out trouble spots in the body and break down blockages responsible for heart attacks, Japanese researchers reported November 14 at a meeting of the American Heart Association. The microscopic packaging seems to improve the drug’s potency and might limit its main drawback — a risk of internal bleeding — by focusing its effect at the clot.
Although the technology has been tested only in pigs, some doctors find the early results intriguing. “This could be a tremendous step forward,” said Roger Blumenthal, a cardiologist at the Johns Hopkins University School of Medicine in Baltimore. If it tests well in people, he said, this controllable form of the clot-busting drug, called tPA, might be a boon for heart attack patients in remote areas that lack hospitals equipped to deliver the highest standard of care for heart attacks.
About half of people for whom heart attacks are fatal die before reaching a hospital and getting angioplasty, in which doctors thread a balloon-tipped catheter up to the heart to prop open blocked coronary arteries with mesh cylinders called stents. With every minute that passes after a heart attack begins, part of the heart muscle is damaged by lack of blood. “It’s one thing to have a heart attack in a metropolitan area,” Blumenthal said. “But sometimes a catheterization lab may be four hours away.” A safer form of tPA, a drug that has largely gone out of use for heart attacks in the United States because of its internal bleeding risk, could play a role In such rural areas, he said.
The Japanese team, led by cardiologist Yoshihiko Saito of Nara Medical University in Kashihara, tested a form of tPA made safer by packaging it in a coating of gelatin-based nanoparticles that prevent tPA from releasing in the blood stream.