PhD Defence Merel Margaretha van der Thiel

Keywords: Brain, Alzheimer’s disease, MRI, waste clearance
 

"A clear look into the brain: MRI insights into the cerebral waste clearance system and cognitive decline"

Brain cells use oxygen and nutrients when they are active, which generates waste products. Recently, scientists rediscovered a waste clearance system in the brain, which works like a sewage system. Fluid flows into the brain through "pipes" called perivascular spaces around blood vessels. It then exchanges with the fluid around brain cells to collect and flush out waste. In diseases like Alzheimer’s disease, this system may malfunction, leading to a buildup of toxic waste products around brain cells. This then contributes to cell damage and leads to dementia.  

This thesis optimized advanced MRI techniques to track how water—and waste—move through the brain. The findings showed that in people with Alzheimer’s disease dementia, fluid movement is more restricted, likely due to waste buildup, which impairs the brain’s clearance system. Additionally, this research suggested that if the blood vessels within the ”pipes” (perivascular spaces) are stiffer and less healthy, this also reduces waste clearance. 
These MRI methods are safe, non-invasive, and useful for monitoring how well the brain clears waste products over time. In the future, they could also help Alzheimer’s trials by tracking the effectiveness of treatments in clearing brain waste. 

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