A new National Institutes of Health-funded study reveals that the brain-destructive culprit of Alzheimer’s disease destroys brain cells in essentially two stages. The Nature Neuroscience study describes how, with the use of sophisticated techniques for brain mapping, the disease progresses.
First, this initial destruction phase is subtle and slow; it begins long before memories falter. And it affects only a small number of vulnerable brain cells. In contrast, the second phase strikes faster and destroys more of the brain. Researchers have linked the second phase to the onset of symptoms. And also to the sudden appearance of plaques tangles and other hallmark manifestations of Alzheimer’s.
Because brain damage begins long before symptoms do, it is even difficult to diagnose the disease. The study helps scientists detect those early changes and points to new insights into how the disease begins. Richard J. Hodes, M.D., director of the NIH National Institute on Aging explained, “The results fundamentally alter scientists’ understanding of how Alzheimer’s harms the brain. They will guide the development of new treatments.”
The researchers studied the brains of 84 individuals to spot the main changes that occur with the disease. The group concentrated on a sort of cellular called an inhibitory neuron, which helps in controlling the activity of the brain. The destruction of neurons in the early stage can, in turn, activate problems in the brain’s circuits, which are closely linked to the onset of Alzheimer’s.
Using sophisticated genetic analysis, investigators in the study also focused their attention on the middle temporal gyrus. A part of the brain involved in the mediation of memory, language, and vision. This particular region of the brain is one of the most frequently affected by Alzheimer’s. By comparing data from people with Alzheimer’s to that from healthy donors, researchers pieced together the sequence of events in the disease’s progression.
Traditionally, scientists have believed that Alzheimer’s damage progresses in distinct stages. With cell death inflammation, and plaque buildup accumulating over time. This paper presented the disease as a two-stage process. One in which slow changes are made and another in which rapid damage coincides with the appearance of symptoms.
In that study, researchers also showed that the loss of SST neurons-essentially. A type of inhibitory neuron-is at the heart of Alzheimer’s-related brain dysfunction. That was surprising because, for years, scientists had believed the disease mainly killed excitatory neurons, which promote activity in the brain.
This study is a subset of the greater Seattle Alzheimer’s Disease Brain Cell Atlas project. This work also highlights the impacts of new technologies developed through the NIH’s BRAIN Initiative. The new tools also allow researchers to detect cellular changes in the brain early on that will help scientists in developing better diagnostics. And treatments for Alzheimer’s disease and other dementias.
ANI
