Fearsome-Smelling Gas Could Have Beneficial Uses in Medicine

A single breath of hydrogen sulfide, a gas best known for its rotten-egg smell, can kill. But at low concentrations, hydrogen sulfide could protect vital organs during surgery, research conducted by a new Emory University School of Medicine professor suggests.

David Lefer, PhD, professor of surgery, came to Emory this summer from Albert Einstein College of Medicine in New York.

Lefer and his co-workers recently showed that delivering hydrogen sulfide to the liver can reduce damage caused by loss and restoration of blood flow in a mouse model of liver surgery. The results are published in the August issue of the American Journal of Physiology, Heart and Circulatory Physiology.

"As a gas, hydrogen sulfide has a number of advantages," Lefer says. "It diffuses across cell membranes, it can be delivered quickly and it protects cells via several basic biochemical pathways."

The authors show that hydrogen sulfide reduces inflammation and oxidative stress when blood flow to the liver is cut off. In the study, hydrogen sulfide is given intravenously, but Lefer says it may be possible to deliver it via inhalation or orally.

Lefer says liver surgery is just one example of a situation where hydrogen sulfide may be beneficial. He and colleagues at Albert Einstein previously showed that hydrogen sulfide can limit scarring and inflammation in the heart muscles of mice after a simulated heart attack. It appears to do so by protecting the mitochondria, the cell's mini-power plants, from structural damage.

Lefer notes that hydrogen sulfide resembles another poisonous gas that has attracted considerable scientific attention over the last decade, nitric oxide. Both gases regulate blood pressure and play key roles in controlling oxidative stress.

Oxidative stress means an abundance of reactive oxygen species, harmful oxygen-containing molecules that interfere with relaxation of blood vessels and trigger the formation of lesions leading to heart attack and stroke.

Lefer says he came to Emory because of opportunities to collaborate with several scientists who work on oxidative stress.

The research was funded by the National Institutes of Health, the American Diabetes Association and a research grant from the biotechnology firm Ikaria Holdings. Lefer is a paid consultant for Ikaria, which is developing technology for hydrogen sulfide delivery.

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