Smelling flatulence, beneficial for those suffering from Alzheimer’s, study reveals

Instead of stopping to smell the flowers, scientists suggest stopping to smell the flatulence. While the thought may be enough to turn your stomach, scientists at Johns Hopkins Medicine say the gas behind that rotten-egg odor, known as hydrogen sulfide, may help protect aging brain cells from Alzheimer’s disease.

Although the smelly gas is very toxic in large quantities, in smaller doses it can provide some important health benefits, according to Johns Hopkins researchers in a study published in the journal Proceedings of the National Academies of Science.

“Our new data strongly link aging, neurodegeneration, and cell signaling through hydrogen sulfide and other gaseous molecules within the cell,” says the study’s corresponding author, Dr. Bindu Paul.

The human body naturally creates small amounts of hydrogen sulfide, which helps regulate the functions of the entire body. Gases can facilitate communication between cells and the brain.

Hydrogen sulfide modifies key proteins through a process called chemical sulfhydration, according to Dr. Solomon Snyder, co-author of the study. Sulfhydration levels in the brain decrease with age, according to scientists, who point out that this trend is more prevalent in Alzheimer’s patients.

“Here, using the same method, we now confirm a decrease in sulfhydration in the Alzheimer’s brain,” said collaborator Milos Filipovic.

As part of the study, scientists at Johns Hopkins Medicine examined mice genetically modified to mimic human Alzheimer’s disease.

A hydrogen sulfide-bearing compound called NaGYY, which slowly released molecules of passenger hydrogen sulfide throughout the body. Over a period of 12 weeks, changes in the mice’s memory and motor function were assessed.

Behavioral tests showed that hydrogen sulfide improved cognitive and motor function by 50 percent compared to rodents that did not receive the injections. Mice that received the treatment were better able to remember platform location changes and appeared more physically active than those that had simulated Alzheimer’s disease but did not receive the treatment.

“The results showed that the behavioral effects of Alzheimer’s disease could be reversed by introducing hydrogen sulfide; but the researchers also wanted to investigate how the brain reacted chemically to the gas molecule,” reads a Johns Hopkins Medicine news release about the study.

key enzyme

A series of experiments revealed a change in a common enzyme called glycogen synthase ß (GSK3ß). When healthy levels of hydrogen sulfide are present, GSK3ß acts as a signaling molecule.

The researchers found that in the absence of hydrogen sulfide, GSK3ß is excessively attracted to another brain protein called Tau.

When GSK3ß and Tau interact, Tau causes clumps inside nerve cells. According to the researchers, as these clumps grow, the tangled proteins block communication between the nerves, eventually causing them to die.

“This leads to the impairment and eventual loss of cognition, memory, and motor function that are hallmarks of Alzheimer’s disease,” the news release states.

“Understanding the cascade of events is important to design therapies that can block this interaction, as hydrogen sulfide is able to do,” said Daniel Giovinazzo, doctoral student and first author of the study.

Until a few years ago, researchers lacked the tools necessary to mimic the way the body produces small amounts of hydrogen sulfide inside cells.

“The compound used in this study does just that, and shows that by correcting brain levels of hydrogen sulfide, we could successfully reverse some aspects of Alzheimer’s disease,” says collaborator Matt Whiteman.