Australian
researchers have come up with a non-invasive ultrasound technology that clears
the brain of neurotoxic amyloid plaques - structures that are responsible for
memory loss and a decline in cognitive function in Alzheimer’s patients.
If a
person has Alzheimer’s disease, it’s usually the result of a build-up of two
types of lesions - amyloid plaques, and neurofibrillary tangles. Amyloid
plaques sit between the neurons and end up as dense clusters of beta-amyloid
molecules, a sticky type of protein that clumps together and forms plaques.
Neurofibrillary
tangles are found inside the neurons of the brain, and they’re caused by
defective tau proteins that clump up into a thick, insoluble mass. This causes
tiny filaments called microtubules to get all twisted, which disrupts the
transportation of essential materials such as nutrients and organelles along
them, just like when you twist up the vacuum cleaner tube.
As we
don’t have any kind of vaccine or preventative measure for Alzheimer’s - a
disease that affects 343,000 people in Australia, and 50 million worldwide -
it’s been a race to figure out how best to treat it, starting with how to clear
the build-up of defective beta-amyloid and tau proteins from a patient’s brain.
Now a team from the Queensland Brain Institute (QBI) at the University of
Queensland have come up with a pretty promising solution for removing the
former.
Publishing
in Science Translational Medicine, the team describes the technique as using a
particular type of ultrasound called a focused therapeutic ultrasound, which
non-invasively beams sound waves into the brain tissue. By oscillating
super-fast, these sound waves are able to gently open up the blood-brain
barrier, which is a layer that protects the brain against bacteria, and stimulate
the brain’s microglial cells to activate. Microglila cells are basically
waste-removal cells, so they’re able to clear out the toxic beta-amyloid clumps
that are responsible for the worst symptoms of Alzheimer’s.
The
team reports fully restoring the memory function of 75 percent of the mice they
tested it on, with zero damage to the surrounding brain tissue. They found that
the treated mice displayed improved performance in three memory tasks - a maze,
a test to get them to recognise new objects, and one to get them to remember
the places they should avoid.
"We’re
extremely excited by this innovation of treating Alzheimer’s without using drug
therapeutics," one of the team, Jürgen Götz, said in a press release.
"The word ‘breakthrough’ is often misused, but in this case I think this
really does fundamentally change our understanding of how to treat this
disease, and I foresee a great future for this approach."
The
team says they’re planning on starting trials with higher animal models, such
as sheep, and hope to get their human trials underway in 2017.
BEC
CREW
18 MAR
2015
You can
hear an ABC radio interview with the team
here.
https://radio.abc.net.au/programitem/peOWD0e2P3?play=true
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