Researchers in the US have found key biological markers relating to the breakdown of the blood-brain barrier are associated with thinking problems and occur independently to changes in the hallmark Alzheimer’s protein’s amyloid and tau. The results are published today (Monday 14 January) in the scientific journal Nature Medicine.
Researchers at the University of Southern California looked at spinal fluid samples from 161 individuals and took MRI scans from participants who did not have memory-related conditions, like vascular dementia.
Important barriers exist between the blood supply and brain as protection against damage and infection. In this study, researchers looked at signs that indicated this blood-brain barrier had broken down.
This involved using MRI brain scans to look at changes to the leakiness of blood vessels in the hippocampus, one of the regions of the brain first affected by Alzheimer’s disease.
The team found that this leakiness was associated with thinking problems even in people without signs of established Alzheimer’s brain changes.
Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK. said:
“The blood-brain barrier plays a crucial role in keeping our brains protected from harm. While we know that the blood-brain barrier breaks down in Alzheimer’s, we tend to think of this as a consequence of the build-up of hallmark Alzheimer’s proteins amyloid and tau. In this in-depth study, researchers found that signs of blood-brain barrier breakdown were linked to thinking problems regardless of whether amyloid and tau proteins were building up in the brain.
“This study didn’t follow participants over time to see if those with signs of blood-brain barrier breakdown went on to develop Alzheimer’s disease and this will be an important question for future research. It is too early to suggest that changes to the brain’s blood vessels could be used in the clinic to help diagnose people with memory and thinking problems sooner, but what is clear, is that the breakdown to the blood-brain barrier warrants more research attention.
“While the build-up of amyloid and tau remain squarely in the sights of scientists working to develop new treatments for Alzheimer’s, we need researchers to approach this challenge from as many different angles as possible. Only through continued investment into dementia research will we be able to understand the biological mechanisms underpinning memory problems, improve diagnosis and ultimately bring about a life-changing dementia treatment.”