Doctors have long known that the creation of a "mini heart attack" - by cutting off and then restoring blood flow to arteries - can actually reduce the damage from a subsequent major heart attack.
Now they may know how that protective effect occurs, according to research from the University of Rochester Medical Centre (URMC), in New York.
The method, called "ischaemic preconditioning" (IPC), somehow shields heart tissue against damage caused by subsequent, prolonged blood vessel blockages.
In their study on rat hearts, the URMC team found that IPC caused more of an important molecule called nitro-linoleic acid (LNO2) to be produced inside cells damaged by a sudden drop in blood supply (ischaemia).
"LNO2 appears to be important in the mechanism by which IPC triggers the body's natural defence mechanisms against heart attack before the major attack comes," Paul S. Brookes, an associate professor of anaesthesiology and of pharmacology and physiology, said in an URMC news release.
"Obviously, this natural response, when it follows a major heart attack, is often too little too late. Our hope is that boosting the effect in patients at high risk, perhaps by administering LNO2 beforehand, will reduce heart attack damage in the future. Even sooner, we may be able to dramatically reduce reperfusion injury suffered in surgical settings," Brookes said.
The findings, published in the current issue of Cardiovascular Research, could lead to the development of new drugs to treat people at high risk for heart attack or stroke. It may also help in efforts to find ways to prevent damage caused when heart surgeons temporarily cut off blood flow to perform coronary artery bypass graft surgeries.
(HealthDayNews, December 2008)