Smelly gas helps hearts
2008-11-12 20:49
Washington - Despite its rotten-egg smell and high toxicity, hydrogen sulphide in small doses helps protect mice from heart failure, according to research published on Tuesday on an experimental treatment that one day could benefit humans.
Potentially life-threatening for miners and sewer workers, hydrogen sulphide 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 colourless, 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 sulphide, 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 sulphide'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 sulphide 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 sulphide showed an ejection fraction 33% higher than the control group (36% compared to 27%), the researchers said.
"Our results show that hydrogen sulphide 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 hospitalisation 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.