Hydrogen sulfide is best known for the stench of rotten eggs, but tiny amounts of the gas produced naturally in the brain may play a critical role in protecting memory — and its absence could contribute to Alzheimer's disease.
Researchers at Johns Hopkins Medicine have identified a protein called CSE (Cystathionine γ-lyase) as a surprising new player in brain health, according to Science Daily. In experiments with genetically engineered mice, animals that lacked the CSE protein developed memory loss, increased oxidative stress, DNA damage, and weakened blood-brain barriers — all hallmarks of Alzheimer's disease.
The challenge is that hydrogen sulfide is toxic in large amounts, making direct delivery to the brain impractical. Instead, the research team, led by associate professor Bindu Paul, is focused on understanding how the brain naturally regulates the extremely small quantities of the gas present in healthy neurons. "The findings suggest that this 'rotten egg' gas, when carefully regulated, may actually protect brain cells and support memory," the researchers reported.
The work builds on years of research at Johns Hopkins. In 2014, a team led by professor emeritus Solomon Snyder found that CSE supported brain health in mice with Huntington's disease. By 2021, the group had shown that CSE was malfunctioning in mice with Alzheimer's, and that tiny injections of hydrogen sulfide helped protect neurons. The new study, published in the Proceedings of the National Academy of Sciences, deepens that picture and is supported by a new grant from the National Institutes of Health.
If further research confirms the findings in humans, boosting CSE activity could offer an entirely new therapeutic strategy — one that works not by clearing amyloid plaques, the traditional target, but by restoring the brain's own chemical defenses.
