Researchers have found a way to prevent the blood vessels of persons with heart disease from constricting when faced with stress. The results, announced today at the annual American Heart Association meeting in New Orleans, could someday lead to a better treatment for coronary artery disease.
The work, by a team of cardiologists at Johns Hopkins University, involves raising blood levels of nitric oxide, a compound that sends messages between cells. Nitric oxide is known to play a critical role in regulating a normal response to stress in which the arteries widen to accommodate increased blood flow to the heart. For reasons that are unclear, the blood vessels of people with coronary artery disease respond to stress by narrowing, which can lead to a heart attack.
In the study, eight subjects--four with coronary artery disease and four without--plunged their hands into icy water, an act that stimulates the "fight or flight" response of stress. Those in the diseased group experienced a narrowing of blood vessels. The team then gave this group arginine, an amino acid essential to the production of nitric oxide. In the second stress test, the vascular activity of the diseased group resembled that of the nondiseased group. Administering arginine had no effect on healthy subjects.
While cardiologists hail the study as illuminating, they caution that it is just a first step toward a better treatment for coronary artery disease. The finding "may someday underpin a therapeutic approach," says William Kussmaul, a cardiologist at Hahnemann University in Philadelphia.