14 Mar 2015

Could ultrasound scans be used to treat Alzheimer's?

From This Way Up, 12:40 pm on 14 March 2015

Australian researchers have shown that medical ultrasound can help rid the brain of the toxic protein that causes Alzheimer's disease.

Alzheimer's is caused by the accumulation in the brain of a protein called beta-amyloid, which builds up to form plaques that can lead to a progressive loss of mental faculties. 40 million people worldwide are already affected by the disease, and that number is expected to triple over the next 50 years as the world population ages. So treatment of the disease is a major priority.

Dr Chris Smith of the Naked Scientists told This Way Up's Simon Morton about a study by two University of Queensland researchers, Gerhard Leinenga and Jurgen Gotz.  Writing in Science Translational Medicine, they have shown that a simple medical ultrasound might be all that's needed to reverse beta-amyloid accumulation.

The duo reasoned that it might be possible to wash out the amyloid from the brain if the blood brain barrier, which isolates the brain from the bloodstream, could be opened up temporarily. To do this, they injected mice with a mixture of "microbubbles". These circulate harmlessly in the bloodstream, but when they are hit by ultrasound waves they collapse in on themselves and create a miniature shock wave.

Dr Smith says that although the treatment involves mice the results look do look promising, with a 58% reduction in beta-amyloid detected in treated mice compared to the control cases, and significantly improved memory and cognitive function.

"Here what they are saying is when we pop these tiny bubbles it temporarily turns off the blood brain barrier...that proteins called albumins leach in from the bloodstream and they bind onto the beta-amyloid and they encourage it to be taken up by immune cells called micro-gliol cells; these are the macrophages or eating cells of the central nervous system and they scavenge this stuff, they devour it and sequester it away....so they are saying we might be able to pull the same stunt in people."