Cocktail of two drugs heals damaged hearts

A cocktail of drugs has been found in trials with animals to heal damaged heart muscle.

According to researchers at the Children's Hospital in Boston, the first chemical overcomes a natural process that stops heart muscle cells from growing and dividing, while the second encourages blood vessels to regrow.

The drug cocktail was trialled on rats following stimulated heart attacks by constricting a coronary artery, but human trials of the treatment are not expected in the immediate future, as the work is still at the basic stages.

Cardiograms of the rats three months after treatment showed that the hearts of those given both drugs were pumping almost as well as those of healthy rats.

Rats injected with only one of the chemicals showed only a temporary improvement.

Study author Felix Engel, an instructor in pediatrics at the hospital, says he is interested in the molecular mechanisms of how the drugs work, and is currently searching for more efficient drugs in order to develop therapies that would be appropriate for humans.

The study nevertheless demonstrates that it is possible to rescue heart muscle, which does not occur naturally after a heart attack.

Following a heart attack the damaged heart muscle is replaced by scar tissue, which can impair the heart's pumping capacity and lead to life-threatening abnormal heart rhythms.

Felix Engel and Mark Keating demonstrated in earlier research that heart cells could multiply in a petri dish if a drug blocked a particular enzyme.

This new trial added a molecule designated FGF1, which stimulates growth of blood vessels, to the treatment given to some of the 120 rats with stimulated heart attacks.

Further tests are now being conducted to see if the treatment is effective when the drugs are administered many hours after a heart attack.

The trick now says Engel is to develop a method of delivering the treatment to the proper location in the body, as FGF1 has the potential for serious side effects if it goes to places other than the heart, and the p38 MAP kinase inhibitor has been shown to damage the liver.

According to the American Heart Association, coronary heart disease (CHD) is the leading cause of death in the United States; and, in adults, heart attacks cause 1 out of every 5 deaths.

The National Institutes of Health (NIH) says more than 1.2 million heart attacks occur each year in the United States and about 460,000 of these are fatal.

Approximately 300,000 people die annually from heart attacks before they can receive medical treatment.

According to the World Health Organization (WHO), coronary heart disease accounts for about 17 million (approximately 30%) deaths annually throughout the world and it is estimated that by the year 2010, heart disease will be the leading cause of death in the world.

The findings will be published in next week's issue of the Proceedings of the National Academy of Sciences, and will be available online this week.