Brain regions with a negative correlation between blood flow and tau. Alzheimer's disease and mild cognitive impairment on the left, cognitively normal on the right. Photo credit: Albrecht et al., JNeurosci 2020
In Alzheimer's disease, impaired blood flow to the brain regions coincides with the build-up of tau proteins. This relationship intensifies as cognition declines, according to new research published in JNeurosci.
Vascular function decreases, and amyloid-β and tau protein build up as Alzheimer's disease progresses, leading to neuron death. As with the proverbial chicken and egg, it remains unclear whether impaired blood flow is or is causing a faulty protein build-up, or whether the two symptoms occur for unrelated reasons.
Albrecht et al. used MRI and PET to compare blood flow and tau formation in the brain of older adults. Perception ranges from cognitively normal to signs of mild cognitive impairment. Areas with elevated tau levels had decreased blood flow, especially in the lower temporal gyrus, one of the first regions in which tau accumulated in Alzheimer's disease before cognitive symptoms were manifested. The relationship was for a separate data pool from the Alzheimer's Disease Neuroimaging Initiative, in which people with mild cognitive impairment and Alzheimer's dementia participated. The correlation between tau and vascular function was stronger in people with greater cognitive impairment and higher amyloid-β levels. It also appeared in more areas of the brain as the disease increased in severity. These results suggest that targeted vascular function could be key to the prevention and treatment of Alzheimer's disease.
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JNeurosci (2020). DOI: 10.1523 / JNEUROSCI.1230-20.2020
Society for Neuroscience
Brain regions with impaired blood flow show higher tau values (2020, October 12)
accessed on October 12, 2020
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