A missing enzyme conveys major heart protection in pre-cli...( DURHAM N.C. Mice born without a cer...)

DURHAM, N.C. Mice born without a certain enzyme can resist the normal effects of a heart attack and retain nearly normal function in the heart's ventricles and still-oxygenated heart tissue, according to a study by researchers at Duke University Medical Center.

The findings raise the possibility of a therapy that could stimulate the growth of blood vessels and limit damage from a heart attack as well as prevent an attack from occurring at all, the scientists said.

Normal mice that went through the same experiment had full heart attacks, suffering damage to their heart pumps and a lack of oxygen in their heart tissues, which are typical effects of a heart attack.

The scientists found that in mice lacking the enzyme GNSOR (or S-nitrosoglutathione reductase) the blood was able to get around the blockage point that normally would cut off blood to the heart because of remarkable capillary growth in these animals.

"There were blood vessels everywhere in these mice born without the enzyme," said Jonathan Stamler, M.D., a Duke professor of medicine and biochemistry and author of the study published in the Proceedings of the National Academy of Sciences online on March 27. "The hope is that this discovery someday could result in a therapy for new blood vessel growth that could be a sort of natural bypass in humans. Perhaps it could also benefit patients with peripheral artery disease, who cannot walk, for example, but who might be able to grow new blood vessels in their legs."

Stamler said his research group might look into the question of improving peripheral artery disease.

"Normally if you block the major artery to a heart, oxygen tension drops in the tissues you can't get oxygen to the tissues and they die," Stamler said. "This appears to be a major step forward in the science of stimulating blood vessel growth around the heart, which many people have been trying to do."

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