Exploiting the body's own ability to fight heart attack; raising questions about anti-depressants, painkillers, beta-blockers

Doctors have long observed that when faced with a heart attack, people who have had a previous one oftentimes fare better than patients who have never had one. Scientists have been working for 25 years to understand one reason why – a process known as ischemic preconditioning, where a temporary restriction of blood flow somehow strengthens cardiac tissues down the road, reports Tom Rickey from the University of Rochester Medical Center.

In the latest research, published in the journal Circulation Research, a group led by Paul Brookes, Ph.D., and graduate student Andrew Wojtovich developed new methods in the effort to track down one of the key molecular agents involved. That molecule, known as the mitochondrial ATP-sensitive potassium channel, or mKATP, is central to ischemic preconditioning, but it has proven elusive for scientists seeking to isolate and describe it. (Read more about their study here.)

Brookes’ team also discovered that mKATP is inhibited by fluoxetine, (Prozac.) It’s the latest in a list of medications that have been shown in the laboratory to impede ischemic preconditioning, Brookes said. Others include painkillers known as cox-2 inhibitors, as well as beta-blockers that are used frequently to treat high blood pressure and heart problems.

Because medications like anti-depressants and beta-blockers are used so widely in patients who have had heart problems, scientists should take a close look at their possible effects on ischemic preconditioning, Brookes said, noting that the drugs have not been linked to any cardiac difficulties in people.