LONDON — Scientists think they might have found a new weapon in the fight against Alzheimer’s disease — not in the form of a drug but in focused beams of ultrasound.
While the approach has been tested only on mice, researchers said it proved surprisingly good at clearing tangles of plaques linked to Alzheimer’s in the animals’ brains and improving their memory, as measured by tests such as navigating a maze.
In the past, high-energy ultrasound has been combined with injected microbubbles, which vibrate in response to sound waves, to get drugs across the so-called blood brain barrier.
But the new research, published on Wednesday in the journal Science Translational Medicine, is the first demonstration that ultrasound alone might have a beneficial effect on the memory-robbing condition.
“Our research was very exploratory, and we really didn’t expect to see such a massive effect,” said Juergen Goetz of the University of Queensland in Brisbane, Australia, one of the study’s authors. “I’m really excited by this.”
After several weeks of treating mice that had been genetically altered to produce amyloid plaques, the scientists found that the ultrasound almost completely cleared the plaques in 75 percent of the animals, without apparent damage to brain tissue.
While there still is some debate as to whether plaques are a cause or a symptom of Alzheimer’s, the experiment found that, across three tests, the treated mice had improved memory compared with untreated ones.
The technique works by stimulating microglial cells, which form part of the brain’s immune system, to engulf and absorb the plaques.
Goetz stressed that his research, which used an ultrasound machine from Philips, was at a very early stage and won’t be tested on people for several years.
Several hurdles must be overcome first, including long-term checks for side effects in animals and much more research into whether the approach will work with thicker skulls and larger brains.
The next step is to treat sheep, with data from that experiment expected later this year.
Ultrasound devices capable of penetrating the human brain already are being tested for other conditions, with the Israeli company InSightec pioneering it for tremors and chronic pain.
Dementia, of which Alzheimer’s is the most common form, affects close to 50 million people worldwide.