Gerhard Leinenga and Jürgen Götz from the University of Queensland in Brisbane, Australia have developed an ultrasound method that has proven to reverse the effects of Alzheimer’s disease in mice. The method also overcomes the problem of transport of drugs across the blood-brain barrier. The development was reported in the edition of the journal Science.
Scanning ultrasound was attenuated to stimulate microglial cells in the fluid surrounding the brain. Microglial cells are a naturally occurring part of the brains immune system and are known to destroy the amyloid plaques that cause the memory loss and other symptoms of Alzheimer’s disease. The method was found to clear 75 percent of the amyloid plaques in mice that had Alzheimer’s disease in a few weeks of regular treatment. The sound waves produced by ultrasound are high energy but they can be controlled so that no damage occurs to healthy tissues.
The method works by creating bubbles at the interface of the blood-brain barrier. The bubbles allow microglial cells to pass through the blood-brain barrier in greater numbers than they normally could. The microglial cells destroy the plaques that cause Alzheimer’s more rapidly because more of the cells can reach the parts of the brain that are damaged by Alzheimer’s.
The procedure has produced similar results in monkeys. The researchers plan on testing the technique on sheep next before they try it on humans. The technique also offers a method for more efficient Alzheimer’s drug delivery across the blood-brain barrier. The major impediment to higher efficacy of Alzheimer’s drugs is making more of the drug cross the blood-brain barrier. The trick will be to find the frequency of ultrasound that allows more drugs into the brain without damaging normal brain tissue and function.
