Enzyme May Unlock Clues to Heart Failure
Newly discovered compound directs cardiac stress response
FRIDAY, July 15, 2005 (HealthDay News) -- Scientists have identified an enzyme they say is key to the heart's response to such stimuli as exercise or stress. It could also prove valuable for research into heart failure.
This cardiac response enzyme -- phosphoinositide 3-kinase (PI (3) K) -- governs the function of beta-adrenergic receptors lying on the surface of heart cells. These receptors are protein switches, activated by the hormone adrenaline, that enhance the heart's pumping action in response to stress or exercise.
In people with heart failure, chronic stress can result in an excess of adrenaline. This over-stimulates the beta-adrenergic receptors, resulting in receptor desensitization and loss, according to researchers at Duke University Medical Center researchers in Durham, N.C.
However, the team has also discovered that blocking certain actions of PI (3) K can help maintain these heart receptors.
"We've uncovered new details of the first step of heart failure, in which heart receptors that normally allow the heart to adapt in the face of changing conditions are lost, rendering the heart unable to pump enough blood to meet the needs of the body's other organs," cardiologist and geneticist Dr. Howard Rockman said in a prepared statement.
"If we could prevent his loss of heart receptors, we might improve heart function in patients with heart failure," he said.
The study will be published in the August issue of the journal Nature Cell Biology.
The American Heart Association has more about heart failure.