One of the biggest mysteries involving Alzheimer’s disease may soon be uncovered.
The question has been whether Alzheimer’s starts at independent regions of the brain at different times, or if it spread to neuroanatomically connected areas.
A new study by Columbia University Medical Center (CUMC) researchers strongly supports the latter, demonstrating that abnormal tau protein, a key feature seen in the brains of those with Alzheimer's, propagates along linked brain circuits, "jumping" from neuron to neuron.
The findings, published in the online journal PloS One, open new opportunities for developing therapies to halt Alzheimer’s progression, researchers said.
"Earlier research, including functional MRI studies in humans, have also supported this pattern of spread," researchers said. "But these various findings do not definitively show that Alzheimer's spreads directly from one brain region to another."
CUMC researchers developed a transgenic mouse in which the gene for abnormal human tau protein is expressed predominantly. The brains of the mice were analyzed at different time points over 22 months to map the protein’s spread.
The researchers found that as the mice aged, the abnormal human tau spread along a linked anatomical pathway.
"This pattern very much follows the staging that we see at the earliest stages of human Alzheimer's disease," researchers said.
The findings of the study have important implications for therapy.
"If, as our data suggest, tau pathology starts in the entorhinal cortex and emanates from there, the most effective approach may be to treat Alzheimer's the way we treat cancer—through early detection and treatment, before it has a chance to spread," researchers said. "The best way to cure Alzheimer's may be to identify and treat it when it is just beginning, to halt progression.”