Just like how our body’s lymphatic system helps clear waste and deliver nutrients, the brain has its own “glymphatic” system responsible for waste removal and nutrient distribution. Problems in this system can contribute to brain diseases like Alzheimer’s and stroke.
Exciting news comes from researchers at Washington University in St. Louis’s McKelvey School of Engineering. They’ve discovered a way to positively affect this glymphatic system using ultrasound, a safe and non-drug method. This breakthrough can provide new insights into brain diseases and overall brain function. The study’s findings were published on May 15 in the Proceedings of the National Academy of Sciences.
The team, led by Hong Chen, an associate professor of biomedical engineering and neurological surgery, introduced a technique they call FUSMB. This method involves focused ultrasound combined with tiny circulating bubbles. The ultrasound travels through the scalp and skull to target specific brain regions. Previous research showed that these bubbles amplify the ultrasound’s effects on blood vessels, creating a pumping action. This helps substances, like medications or gene therapies, reach the brain more effectively.
“Intranasal delivery offers a new, non-invasive way to explore the glymphatic pathway in intact brains,” explained Chen. This approach could be a game-changer for understanding how the glymphatic system works in humans, which has been a challenge due to the lack of non-invasive methods.
In their study, the team introduced a special tracer through the nose, and then used focused ultrasound on the brain’s thalamus area after injecting microbubbles into the bloodstream. They found that FUSMB improved the movement of the tracer around blood vessels in the brain.
To ensure the accuracy of their findings, they compared their results with three control groups using different combinations of ultrasound, microbubbles, and the tracer. All control group mice showed lower tracer movement, confirming that the enhanced movement was indeed due to the focused ultrasound combined with microbubbles.
The researchers further validated their findings by using the FUSMB technique after directly injecting the tracer into the cerebral spinal fluid, a commonly used but invasive method. They found that FUSMB also boosted tracer movement around the blood vessels in the brain, proving its effectiveness.
The team investigated different types of blood vessels, including arterioles, capillaries, and venules, for their role in enhancing tracer movement using both intranasal and injected delivery. They observed improved tracer movement in both arterioles and capillaries with both delivery methods. The fluorescence was brighter along arterioles compared to capillaries and venules.
This groundbreaking research opens the door to using ultrasound and microbubbles as a non-invasive and drug-free way to enhance waste removal in the brain. This could potentially help alleviate brain diseases caused by glymphatic system issues, as stated by Dezhuang (Summer) Ye, a postdoctoral research associate on the team.
Looking ahead, Chen’s team plans to use this non-invasive method to tackle neurodegenerative diseases like Alzheimer’s and Parkinson’s. This discovery offers hope for more effective treatments in the future.
-A Balanced Brain is a Better Brain for a Happier Life-