New evidence that Alzheimer's disease is infectiousS

Alzheimer's disease is caused in part by a build-up of protein debris in the brain. Scientists already knew that this protein debris, called amyloid peptides, is infectious. But now it turns out that it's easier to catch than they thought.

Neurologist Yvonne S. Eisele and her team had already proven that mice could catch Alzheimers from each other, but only if the brain of a healthy mouse was injected with amyloids from mouse who already had Alzheimer's symptoms. Now a further study reveals that injecting mice with the amyoids anywhere on their bodies ultimately results in Alzheimer's as well.

Amyloid peptides are misfolded proteins, junk molecules that a healthy brain can clear away and reabsorb back into the body. But Alzheimer's sets in when the amyloids aren't cleared away, and they harden into plaques. What Eisele's new research shows is that even if these amyloids enter the body through the arm, they can find their way to the brain and potentially cause Alzheimer's.

A release about the study explains:

[An amyloid peptide called] beta-amyloid can also cause mishap when introduced outside the brain. When the researchers injected beta-amyloid-containing brain extract in the bodies of mice, the animals developed symptoms of Alzheimer's after several months. While it remains unclear how the injected beta-amyloid caused disease, the authors believe that mechanisms exist allowing for the transport of beta-amyloid from peripheral tissues to the brain.

No, this does not mean you can "catch" Alzheimer's from somebody by brushing against them, or by touching them when you have a cut on your arm. You'd have to scrape a chunk of infected gray matter out of someone's skull, and then inject it into your body, before the situation got dangerous.

What the study does show is that amyloids could be building up elsewhere in people's bodies and then finding their way into their brains. And could help researchers figure out how Alzheimer's develops.

Or it could lead to a seriously creepy science fiction movie where a supervillain steals the brains of Alzheimer's patients and injects people with them secretly in order to wreak havoc.

Read the full scientific paper via Science