Dementia breakthrough: Alzheimer’s disease symptoms may NOT start in brain

Dementia affects 850,000 in the UK and is a leading killer, and Alzheimer’s disease is its most common form.

The condition has long been associated with the brain since it affects memory, thinking, information processing and decision-making.

But new research suggests that it may actually begin elsewhere in the body.

A study by the University of British Columbia found that breakdowns in other areas could trigger brain-related symptoms.

In a study using mice, scientists found that an Alzheimer’s-causing protein, amyloid-beta, could travel - like cancer - to the brain from other parts of the body.

It is the first time researchers have shown that when the protein develops outside the brain it could still contribute to Alzheimer’s.

Past studies have associated amyloid-beta with cognitive decline.

In Alzheimer’s sufferers it forms clumps - or ‘plaques’ - that smother brain cells.

Amyloid-beta is produced in blood platelets, blood vessels and muscles, and its precursor protein is found in several other organs in addition to the brain.

The researchers believe that future Alzheimer’s drugs could now target the kidney or liver, and remove the toxic protein from the blood before it reaches the brain.

This may be more effective than drugs that directly target the brain, which is complex, sensitive and often hard to reach. 

It is thought that a drug could bind to amyloid-beta throughout the body in a way that allows the kidneys and liver to clear it out.

“The blood-brain barrier weakens as we age,” said Dr Weihong Song, from the University of British Columbia.

“That might allow more amyloid beta to infiltrate the brain, supplementing what is produced by the brain itself and accelerating the deterioration."

The findings suggest that Alzheimer’s is a ‘whole body’ problem, rather than one just related to the brain.

“Alzheimer's disease is clearly a disease of the brain, but we need to pay attention to the whole body to understand where it comes from, and how to stop it," added Song.