Previously, ultrasounds were used to activate tiny nanobubbles and release drugs past the blood-brain barrier. This is the first time however that ultrasounds alone were demonstrated to improve memory in mice. Professor Jürgen Götz, the director of the Clem Jones Centre for Ageing Dementia Research in Australia and one of the study's authors, said:
“We’re extremely excited by this innovation of treating Alzheimer’s without using drug therapeutics.
The ultrasound waves oscillate tremendously quickly, activating microglial cells that digest and remove the amyloid plaques that destroy brain synapses.
The word ‘breakthrough’ is often mis-used, 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.”
Alzheimer's is linked to neurotoxic amyloid plaques that cause memory loss and cognitive decline. Plaques consist of largely insoluble deposits of an apparently toxic protein peptide, or fragment, called beta-amyloid. We now know that some people develop some plaques in their brain tissue as they age.
Götz's team genetically modified mice to produce amyloid plaques, then treated these with focused ultrasound beams which stimulate microglial cells. These are part of the brain’s immune system, and once activated they engulf and absorb the plaques. The ultrasound sessions almost completely cleared the plaques in 75% of the animals, without apparent damage to brain tissue.
We still do not know whether amyloid plaques themselves cause Alzheimer's or whether they are a by-product of the Alzheimer's disease process. Even so, the mice who had their plaques cleared showed improved memory comparable to normal mice.
Professor Götz said:
“This treatment restored memory function to the same level of normal healthy mice.
We’re also working on seeing whether this method clears toxic protein aggregates in neurodegenerative diseases other than Alzheimer’s and whether this also restores executive functions, including decision-making and motor control.”
The researchers said a human clinical trial is years away. They envision a mobile device that can be taken home by patients and used several times a year. This could be much more effective than any Alzheimer’s treatment currently used. A lot cheaper too, considering treatments can be as stiff as $25,000.
“With an ageing population placing an increasing burden on the health system, an important factor is cost, and other potential drug treatments using antibodies will be expensive
In contrast, this method uses relatively inexpensive ultrasound and microbubble technology which is non-invasive and appears highly effective,” according to Gotz.
The next trial is slated to test whether the treatment also works on sheep. Findings appeared in the journal Science Translational Medicine.
