Alzheimer’s disease damages the brain before any symptoms begin to appear, new research suggests. This is part of a new two-step model of Alzheimer’s progression, which features an early “silent” stage of brain damage.
Alzheimer’s affects roughly 5.8 million Americans, according to the U.S. Centers for Disease Control and Prevention. The progressive disease is the most common form of dementia and is associated with memory loss and cognitive decline in the brain regions involved in thought, memory and language.
The disease is associated with a buildup of abnormal proteins inside and around our brain cells, the accumulation of which was thought to occur during the earliest stage of the disease. However, according to new research, this destructive protein accumulation might occur further down the disease’s timeline than we once thought.
With the help of sophisticated brain-mapping tools, a team of Seattle researchers from the Allen Institute of Brain Science and the University of Washington analyzed the brains of 84 deceased donors at various stages of cognitive decline.
What they found were two distinct phases during the disease’s progression. The first was marked by an increase in inflammation and the loss of three key brain cell types. The second was marked by the distinctive buildup of abnormal proteins and brain cell loss seen in Alzheimer’s patients.
A doctor holds up a brain scan. Alzheimer’s disease may progress in two distinct phases, new research suggests.
Makhbubakhon Ismatova/Getty
“One of the challenges to diagnosing and treating Alzheimer’s is that much of the damage to the brain happens well before symptoms occur,” Richard Hodes, director of the National Institutes of Health’s National Institute on Aging and one of the study’s co-authors, said in a statement.
“The ability to detect these early changes means that, for the first time, we can see what is happening to a person’s brain during the earliest periods of the disease,” he said.
Hodes continued: “The results fundamentally alter scientists’ understanding of how Alzheimer’s harms the brain and will guide the development of new treatments for this devastating disorder.”
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Reference
Gabitto, M.I., Travaglini, K.J., Rachleff, V.M., Kaplan, E.S., Long, B., Ariza, J., Ding, Y., Mahoney, J.T., Dee, N., Goldy, J., Melief, E.J., Agrawal, A., Kana, O., Zhen, X., Barlow, S. T., Brouner, K., Campos, J., Campos, J., Carr, A.J., Lein, E.S. (2024). Integrated multimodal cell atlas of Alzheimer’s disease. Nature Neuroscience, 1–18. https://doi.org/10.1038/s41593-024-01774-5
