BBC Sunday, 29 April, 2001, 23:04 GMT 00:04 UK

Drug limits heart attack damage

Heart attacks can leave survivors with permanent damage A drug which appears to be able to "mop up" damaging molecules produced after a heart attack could improve recovery.

A cardiac arrest, in which the muscles of the heart stop because they are starved of oxygen, can lead to severe tissue damage.

This severely hampers the chances of a patient making a full recovery.

Much of this tissue damage is caused by molecules called "free radicals" which are produced in large quantities in the heart muscle during a heart attack.

Free radicals can cause sufficient damage to cell DNA to trigger individual cells to die.

Once the blood flow is re-established by doctors following a heart attack, these molecules move to other areas of tissue and can cause widespread cell death and the formation of scar tissue.

Encouraging results

The more scar tissue replaces heart muscle, the less efficient the heart will be at pumping blood.

The new drug, developed by Wake Forest University School of Medicine, has been tested on animal hearts - and the results have been encouraging.

In rats, the drug M40403, administered after heart attack but before the blood flow has been fully restored, seemed to have a protective effect against the free radicals.

Dr Mark Payne, associate professor of paediatric cardiology at Wake Forest, said: "The applications of this research are enormous. More animal studies need to be completed before we can move to clinical trials, but I am optimistic.

"Normally these cells have coping mechanisms to deal with free radicals that are generated within the cells in low amounts.

'Overwhelmed'

"But when the heart has suffered an attack, the cells become overwhelmed and cannot cope with the enormous burst of free radicals that are produced when blood flow is re-established to the injured regions of the heart.

"As a result, the cells die and are replaced by scar tissue."

The principal advantage of M40403 is the size of its molecules.

These are tiny enough to penetrate into tissues such as the brain and the heart.

Good diet

The same molecule has also been used in animals to try to reduce stroke damage.

Free radicals are frequently mentioned in relation to good diet, as they are theoretically implicated in the development of some cancers.

It is suggested their ability to damage cell DNA may trigger abnormal growth and division - a feature of cancer development.

It is suggested that consumption of vitamins A, C and E can help remove them from circulation because the vitamins can bind to the free radicals and neutralise their effects.

-- Anonymous, April 29, 2001