New research may have found a link between abnormal levels of amyloid protein in the blood and changes to microstructures, the combination of which may signal the development of Alzheimer’s disease. The study findings are published in Alzheimer’s & Dementia. [1]
The change in the brain can be seen on an MRI and, along with a blood test, could lead to new way to detect early Alzheimer’s disease, even in patients who display no clinical symptoms of dementia.
Researchers from 1Florida Alzheimer’s Disease Research Center and the University of Florida (UF) College of Health and Human Performance conducted a study on 128 volunteers, some of whom had been diagnosed with dementia. The participants underwent a PET scan, used to detect amyloid plaque in the brain, which typically signals that a patient has Alzheimer’s disease.
In the study, some participants showed no sign of plaque on imaging scans and were free of symptoms. However, they still had elevated levels of amyloid proteins in their blood. Researchers gave that cohort a diffusion MRI scan, only to discover structural abnormalities that coincided with high levels of the protein.
The changes seen in the brain are consistent with Alzheimer’s, the researchers noted, and it may mean that PET scans are not sufficient to spot the disease in its early stages.
“Previously people would say one of the earliest events you would see is amyloid positivity in the brain on a PET scan,” senior author of the study David Vaillancourt, PhD, from UF College of Health and Human Performance said in a statement. “Our findings suggest there seem to be events occurring both in the blood and in the brain before you detect amyloid positivity in the brain.”
Diffusion MRI results for the patients flagged as potentially having early Alzheimer’s displayed abnormal levels of free-water in the brain, or fluid unconstrained by tissue, often a sign of dead cells and inflammation. Related research has shown free-water is a sign of atrophy in the brain and a biomarker for neurodegenerative disorders such as Parkinson’s.
While the researchers are hesitant to say the combination of excess free-water and amyloid in the blood is definitively a sign of Alzheimer’s, it’s a warning sign for follow-up assessments like cognitive assessments and additional brain imaging to monitor potential progression of neurodegeneration.
This research will hopefully lead to earlier interventions, Vaillancourt said. It opens the door for more studies to find a true biomarker for early stages of the disease. As a next step, his research team plans to follow up with the study participants to see if free-water detected on an MRI eventually leads to positive findings for plaque on a PET scan.
“We want to follow them over time to better understand the trajectory of change,” Vaillancourt added.
The full study is available by here.
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