Microbubbles injected into the blood vibrate under ultrasound, temporarily forcing cells lining the blood-brain barrier apart. This may allow amyloid-fighting antibodies to slip into brain tissue (shown) or rouse cells that clean up the protein.
Ultrasound combined with microbubbles has been a promising new way of penetrating the blood-brain barrier (see flashbacks below). Once microbubbles are injected, an ultrasound probe is pointed toward the treatment site. As microbubbles pass through the ultrasound beam, they vibrate and deform in different ways, pushing on cells within the blood-brain barrier. This pushing and shoving seems to open up temporary passages in the barrier, allowing drugs to be pushed through that would otherwise have a next to zero chance of reaching the brain. In a new development, researchers now are finally showing that this technique may work in allowing neurological conditions to be treated with existing and future drugs that are naturally blocked by the blood-brain barrier.
The team from The University of Queensland in Australia have successfully removed amyloid plaque from the brain and restored memory in a mouse model of Alzheimer’s disease. They injected the mice with the microbubbles and swept the ultrasound beam across the entire brain. The treatment was repeated almost daily. After these treatments the mice were put through three memory intensive tasks. Compared to the control group that received microbubbles but no ultrasound, the mice showed “full restoration of memory in all three tasks,” according to the researchers. The next step is to try this out in clinical trials. We hope these results can be replicated and brought to practice as soon as possible.
Some details from the study abstract in Science Translational Medicine:
Spinning disk confocal microscopy and high-resolution three-dimensional reconstruction revealed extensive internalization of Aβ into the lysosomes of activated microglia in mouse brains subjected to SUS, with no concomitant increase observed in the number of microglia. Plaque burden was reduced in SUS-treated AD mice compared to sham-treated animals, and cleared plaques were observed in 75% of SUS-treated mice. Treated AD mice also displayed improved performance on three memory tasks: the Y-maze, the novel object recognition test, and the active place avoidance task.
Flashbacks: Temporarily Opening Up the Blood-Brain Barrier Using Ultrasound Waves…; Microbubbles Help Ultrasound See Blood Vasculature Like Never Before…; Non-Invasive Brain Acoustic Drug Delivery…; Blood-Brain Barrier Opened With Ultrasound Implants to Let Drugs Through…
Study in Science Translational Medicine: Scanning ultrasound removes amyloid-β and restores memory in an Alzheimer’s disease mouse model…
More from Science/AAAS News: Ultrasound therapies target brain cancers and Alzheimer’s disease…
