Hydrogen sulfide may protect against Alzheimer's disease

Scientists at Johns Hopkins University have shown in experiments on mice that hydrogen sulfide gas can protect aging brain cells from Alzheimer's disease. The discovery of the biochemical reactions that make this possible opens the door to developing new drugs for neurodegenerative diseases. The findings are published in Proceedings of the National Academy of Science.

The human body normally synthesizes small amounts of hydrogen sulfide, which helps regulate functions throughout the body from cellular metabolism to dilation of blood vessels. Gases have previously been shown to be major cell-mediated molecules of particular importance in the brain. They act through a variety of mechanisms to ensure rapid messaging between cells. In the case of hydrogen sulfide, modification of target proteins occurs through a process called chemical sulfhydration, which alters their activity.

Previous studies have shown that sulfhydration levels in the brain decrease with age, a trend that increases in patients with Alzheimer's disease. In the current work, scientists studied genetically modified mice with simulated Alzheimer's disease. The mice were injected with the compound NaGYY, which slowly releases hydrogen sulfide molecules as it travels through the body. The researchers then tested the mice for changes in memory and motor function over a 12-week period.

Behavioral tests showed that hydrogen sulfide improved cognitive and motor function by 50 percent compared to mice that were not injected with NaGYY. The treated animals could remember better and seem more physically active. Thus, by correcting the levels of hydrogen sulfide in the brain, scientists were able to successfully reverse some of the symptoms of Alzheimer's disease.