As a researcher, Nathan McDannold, Ph.D. is on a quest to improve the delivery of drugs to the brain. “Most drugs don’t actually get into the brain when you inject them into the body or if a person takes a pill because of the blood-brain barrier,” he explains. “It places a big limitation on what drugs you can use.”
In preclinical studies a decade ago, McDannold and his colleagues made an important discovery: the blood-brain barrier (BBB) could be temporarily disrupted without causing damage. Doing so involved the use of pulsed, low power ultrasound combined with small microbubbles filled with a contrast agent for ultrasound imaging.
Since then, McDannold’s goal has been to translate this discovery into safe and effective patient therapies that not only treat brain disorders but also precisely target where drugs are delivered. He is now investigating the use of MR-guided focused ultrasound in opening the BBB. The approach has so far proven successful and safe in large animal models.
Encouraging research has also been performed by Eun-Joo Park, Ph.D., a research fellow on McDannold’s team. “She looked at treating breast cancer metastases in the brain using Herceptin,” McDannold explains. “A lot of patients get breast cancer, and they respond well to drugs. But when it metastasizes to the brain, they don’t respond to the drugs very well anymore. So, we hope that by disrupting the blood-brain barrier in the tumor and around it, we can get drugs into the brain and help these patients.”
McDannold envisions many brain disorders benefitting from focal drug delivery. “There are some results in animals showing that we can actually clear out some of the plaques that are formed in Alzheimer’s. There are other applications for diseases like Parkinson’s or multiple sclerosis, potentially,” he observes. “This stuff is really wide open for us to look at. We’re just sort of scratching the surface and developing the technology that will enable a lot of other research.”
Written by Ellen C., McKenna