Alzheimer’s: hidden phase of “early” brain damage revealed by neuroscientists

Alzheimer’s disease damages the brain before any symptoms begin to appear, new research suggests. This is part of a new two-stage model of Alzheimer’s disease progression that features an early, “silent” stage of brain damage.

Alzheimer’s disease affects about 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 regions of the brain involved in thinking, memory and language.

The disease is associated with an accumulation of abnormal proteins in and around brain cells, the accumulation of which occurred during the early stage of the disease. However, according to new research, this destructive accumulation of proteins may occur further along the disease timeline than we thought.

With the help of sophisticated brain mapping tools, a team of Seattle researchers from the Allen Institute for Brain Science and the University of Washington analyzed the brains of 84 deceased donors in various stages of cognitive decline.

What they found were two distinct phases during disease progression. The first was marked by increased inflammation and the loss of three main types of brain cells. The second was marked by the distinct accumulation of abnormal proteins and loss of brain cells seen in Alzheimer’s patients.

“One of the challenges in diagnosing and treating Alzheimer’s disease is that much of the damage to the brain happens well before symptoms occur,” said Richard Hodes, director of the National Institute on Aging at the National Institutes of Health and one of the study’s co-authors. in a statement.

“The ability to detect these changes early means that, for the first time, we can see what is happening to a person’s brain during the early periods of the disease,” he said.

Hodes continued: “The results fundamentally alter scientists’ understanding of how Alzheimer’s disease harms the brain and will guide the development of new treatments for this devastating disease.”

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Reference

Gabitto, MI, Travaglini, KJ, Rachleff, VM, Kaplan, ES, Long, B., Ariza, J., Ding, Y., Mahoney, JT, Dee, N., Goldy, J., Melief, EJ, Agrawal , A., Kana, O., Zhen, X., Barlow, S.T., Brouner, K., Campos, J., Campos, J., Carr, A.J., Lein, E.S. (2024). Integrated multimodal cellular atlas of Alzheimer’s disease. Natural Neuroscience, 1–18. https://doi.org/10.1038/s41593-024-01774-5