Beta-blockers for heart patients a double-edged sword

Washington, Nov 22 (ANI): Researchers from University of Illinois have discovered that a particular class of heart medications called beta-blockers can have a helpful as well as harmful effect depending on their molecular activity.

The study showed that use of carvedilol in combination with inhibitors of angiotensin-converting enzyme (ACE inhibitors) may be of the greatest benefit to cardiac patients, and has significant clinical implications on which beta-blockers patients should take.

"I think this is really good stuff," said Kevin Xiang, a professor of molecular and integrative physiology at the University of Illinois led the study.

"It definitely will help people along the way to understand how to further manipulate this system. Beta blockers are still the most commonly used drug for heart disease," Xiang added.

Beta-blockers that target both the alpha- and beta-receptors on the heart muscle offer the most benefit to cardiac patients, while those that target only the beta-receptors can actually undermine the structure and function of the heart.

Patients with heart disease usually have higher levels of catecholamines - hormones that activate the beta-adrenergic receptors to stimulate cardiac muscle contraction.

A 2003 study showed that the beta-blocker carvedilol produced a greater survival benefit than another drug, metoprolol tartrate. Carvedilol targets both the beta- and alpha-adrenergic receptors.

The new study unveiled an elegant intracellular signalling system in which beta-receptor activation modulates alpha-adrenergic signaling.

It showed that blocking the beta-receptor alone promotes cardiac remodelling via growth of cardiac fibroblasts induced by alpha-adrenergic receptor signaling. The growth of fibroblasts in the heart further damages the integrity and function of the heart.

The study appears in journal Circulation Research published by the American Heart Association. (ANI)