Gas that smells like rotten eggs could protect against Alzheimer’s

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  • Hydrogen sulphide is a gas known for smelling like rotten eggs
  • A recent study shows that the gas might be useful in protecting brains against Alzheimer's disease
  • This opens up the possibility for developing new treatments to combat neurodegenerative disease


Alzheimer's disease is a progressive illness characterised by the degeneration of brain tissue, and is the leading cause of dementia.

A new study published in Proceedings of the National Academy of Science of the United States of America (PNAS) found that hydrogen sulphide may help protect the brain against ageing, which may lead to Alzheimer’s disease.

What is hydrogen sulphide?

Hydrogen sulphide is a chemical compound (in the form of a gas) that has a foul odour like rotten eggs. The gas is produced in very small quantities by our bodies, and also "occurs naturally in sewers, manure pits, well water, oil and gas wells, and volcanoes".

The field of gasotransmission indicates that gases (such as hydrogen sulphide) play a vital role in cellular messaging between molecules in the brain. The problem is that gases cannot be stored in vesicles (structures inside or outside a cell) like neurotransmitters, and as a result, gases act through a different mechanism to accelerate cellular messaging.

Cellular messaging with hydrogen sulphide involves modifying "target proteins" through a process called chemical sulfhydration. 

"Our new data firmly link ageing, neurodegeneration and cell signalling using hydrogen sulfide and other gaseous molecules within the cell," says Dr Bindu D. Paul, lead corresponding author of the study.

Mice with Alzheimer's

A new method is being used by a number of studies to show that sulfhydration levels in the brain decrease with age, and even more so in the case of Alzheimer's disease (AD).

"Here, using the same method, we now confirm a decrease in sulfhydration in the AD brain," says one of the collaborators, Milos Filipovic.

For the purpose of the study, the researchers used mice that had been genetically engineered to mimic Alzheimer's disease. They injected the mice with a compound carrying hydrogen sulphide, that slowly releases the gas through the body.

They then conducted behavioural tests on the mice for a period of 12 weeks and found that cognitive and motor function improved by 50% compared to the mice that did not receive the injections.

"Understanding the cascade of events is important to designing therapies that can block this interaction like hydrogen sulfide is able to do," says co-author Daniel Giovinazzo.

Matt Whiteman, a collaborator of the study, concluded:

"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."

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