Small Doses of Toxic Gases Protects Mice from Heart Failure

by VR Sreeraman on Nov 12 2008 11:43 AM

Despite its rotten-egg smell and high toxicity, hydrogen sulfide in small doses helps protect mice from heart failure, according to research published Tuesday on an experimental treatment that one day could benefit humans.

Potentially life-threatening for miners and sewer workers, hydrogen sulfide has been recently found in the human body and mammals in general, where it is produced in minute quantities and linked to multiple physiological benefits.

The colorless, flammable gas helps regulate blood pressure and reduce inflammation, said the study's chief author David Lefer, professor of surgery at Emory University School of Medicine, in Atlanta, Georgia.

Hydrogen sulfide, the researchers said, appears to stimulate heart muscle cells to produce their own antioxidants and molecules that stave off programmed cell death, a response to the loss of blood flow.

The study was presented at the American Heart Association's annual conference meeting since the weekend at New Orleans, Louisiana.

To test hydrogen sulfide's effects on the heart, the scientists created a model of cardiac failure in mice by blocking their left coronary arteries either temporarily for an hour or permanently, causing part of their heart muscles to die.

Some of the laboratory mice were treated with a solution of hydrogen sulfide administered intravenously once a day, for a week. The rest made up the control group and were left untreated.

Four weeks later, researchers tested both groups' heart capacity through their "ejection fraction," a measure of heart function.

The mice treated with hydrogen sulfide showed an ejection fraction 33 percent higher than the control group (36 percent compared to 27 percent), the researchers said.

"Our results show that hydrogen sulfide can blunt the impact of heart failure on heart function and mortality in a mouse model of heart failure," said the study's co-author John Calvert, assistant professor at Emory University.

Heart failure, a leading cause of hospitalization for the elderly, occurs when the heart muscle cannot pump enough blood to meet the body's needs.

Previous injury to the heart muscle from a heart attack, obesity, diabetes or high blood pressure are all contributing factors.

The research was funded by the National Institutes of Health, the American Diabetes Association and by a research grant from the biotechnology firm Ikaria Holdings.