Carbon monoxide could help to protect cells against damage from Alzheimer's disease, according to new research.
Scientists at the University of Leeds have found that the gas may protect against amyloid beta, a hallmark of the condition.
Although carbon monoxide is toxic in large quantities, small amounts are present in the body, where they play important roles such as helping to regulate blood pressure. In the brain, the gas helps nerve cells to communicate with each other.
Previous research has shown that increased levels of carbon monoxide are present in the brains of people with Alzheimer's, and the team from the University of Leeds set out to establish the role it might play in the condition.
They placed nerve cells in a dish and added the toxic amyloid protein, which builds up in the brains of those with Alzheimer's and forms sticky clumps around cells. Their results showed that this caused around half of the cells to die.
However, far fewer cells died when carbon monoxide was added, suggesting it was able to prevent some of the damage caused by amyloid.
Earlier research carried out by the same team had indicated that amyloid may cause damage by activating an enzyme called AMPK, which is important for regulating the amount of energy available to cells.
In the latest study, they discovered that carbon monoxide prevented amyloid from activating this enzyme.
Study co-author Dr Mark Dallas, who is now based at the University of Reading, said: "Our study builds on a body of work linking carbon monoxide to Alzheimer's, and suggests that the increased amounts we see in people with the disease may be a result of a mechanism the brain uses to protect itself."
He added that while the role of carbon dioxide in Alzheimer's is not yet fully understood, the team's research could provide a new lead in the search for new treatments.
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