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WASHINGTON (AP) – A handful of patients with Alzheimer's disease have embarked on a daring experiment: they let scientists send sound waves into the brain to temporarily agitate an opening in its protective shield .
The so-called blood-brain barrier prevents germs and other harmful substances from getting into the bloodstream – but it can also block drugs against Alzheimer's disease, brain tumors and other diseases. Other neurological diseases.
Canadian researchers reported Wednesday that the technology called focused ultrasound can punch holes in this barrier – holes that close quickly – a step towards a day using the non-invasive device to pbad the treatments of the brain.
[Traduction] "For decades, neuroscience has been pursuing a major goal, the idea of a safe and reversible way to cross the blood-brain barrier," said Dr. Nir Lipsman, Sunnybrook neurosurgeon. Toronto Health Sciences Center. study. "It's exciting."
The findings were presented at the International Conference of the Alzheimer's Association in Chicago and published in Nature Communications.
This first-stage research, conducted in only six people with mild-to-moderate Alzheimer's, tested whether patients' fragile blood vessels could withstand the bruise without bleeding or other side effects – it did not occur. not tested potential therapies.
More security testing is needed, but "it's certainly promising," said Dr. Eliezer Masliah of the National Institute on Aging, who did not participate in the event. 39; study. "What is remarkable is that they can do it in a very targeted way, they can target a very specific brain region."
Alzheimer's disease is not the only target. A similar safety study is underway in Lou Gehrig's disease. And researchers are testing whether the tool is helping more chemotherapy reach the right place in people with a deadly brain tumor called glioblastoma.
"We do not want to open the blood-brain barrier everywhere, we want to open the blood-brain barrier where we want the treatment to be administered," said Dr. Graeme Woodworth of the University Medical Center. Maryland. , who will soon conduct a study on brain tumors.
Scientists have long tried different strategies to overcome the blood-brain barrier with little success. The blood vessels in the brain are lined with cells that form tight junctions, almost like a zipper. The barrier lets in some small molecules. Often, treatments for brain diseases are too big to pbad easily.
The new approach: scientists inject microscopic bubbles into the bloodstream. With an MRI scanner, they aim at a specific area of the brain. Then they emit ultrasonic waves through a helmet-like device at that location. The pulses of energy make the microbubbles vibrate, releasing these junctions resembling zippers in the hope that drugs could slip inside.
Within minutes, Lipsman's team saw a medical dye appear on brain scans of patients with Alzheimer's disease – evidence that the barrier was open. A repeat badysis the next day showed that it was closed again. The patients repeated the procedure a month later.
The researchers reported no serious side effects, and no deterioration of cognitive function. The study was funded by the non-profit Focused Ultrasound Foundation.
"This is not painful or anything," said Rick Karr, of Everett, Ontario, the first participant in the study.
A retired truck driver and amateur musician, Karr was diagnosed with Alzheimer's in 2011. The doctors said that the study would not address his memory problems, but "I feel privileged", Karr said in an interview. "I could help somebody else on the road.
A French company, CarThera, tests a different ultrasound technique for brain tumors, using an implant attached to the skull during surgery.
For non-invasive ultrasound, the manufacturer of InSightec devices has authorization from the Food and Drug Administration to begin the Maryland tumor trial and a small US study on the disease of 39; Alzheimer.
This time, scientists will look deeper at the brains affected by Alzheimer's disease in a key region of memory, said Dr. Ali Rezai, senior researcher at Rockefeller's Neuroscience Institute. West Virginia University. And they will measure if simply opening the barrier could help the body eliminate sticky plaques that are a hallmark of Alzheimer's disease, after studies on the mouse have suggested that it's a possibility.
But by far the greatest interest is in the use of ultrasound to administer medication – if the studies of the next stage conclude that it is safe to say "it is safe. try.
"The blood-brain barrier is no longer prohibited," Rezai said.
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