Scientists Just Discovered A Potential New Alzheimer's Cause

Yahoo

12-02-2025

The exact cause of Alzheimer's disease has long evaded scientists, but experts typically suggest there are likely several factors (like genetics, environment, and lifestyle) that contribute to its development. We already know that getting good sleep, exercise, a heart-healthy diet, and regular socialization can lower your risk for the disease. But no one has yet been able to pinpoint why some develop the devastating condition while others don't. Now, new research published in the journal Alzheimer's & Dementia suggests that there could actually be a single, simple cause of Alzheimer's disease.
This hypothesis is pretty radical, and goes against what most experts in the field believe. But understanding the root cause (or causes) can help prevent, diagnose, and treat Alzheimer's in the future.
Here's what one new scientific model suggests about Alzheimer's cause, and what it means for us.
Meet the experts: Carol Huseby, PhD, is assistant professor in the Banner Neurodegenerative Disease Research Center at Arizona State University; Verna Porter, MD, is a neurologist and director of the Dementia, Alzheimer's Disease, and Neurocognitive Disorders at Pacific Neuroscience Institute at Providence Saint John's Health Center in Santa Monica, CA. Michal Schnaider Beeri, PhD, is the director of the Herbert and Jacqueline Krieger Klein Alzheimer's Research Center at Rutgers Robert Wood Johnson Medical School
The study analyzed existing research and data, including a 2022 study that found most biological pathways can be linked to Alzheimer's disease, and proposed that "stress granules" may be the reason Alzheimer's disease develops in some people and not others.
Specifically, the researchers explored how the presence of these "stress granules" disrupt molecule movement between a cell's nucleus (the center part of a cell that contains genetic material) and its cytoplasm (the jelly-like substance that surrounds the nucleus where important chemical processes occur). The disruptions mess with a slew of essential biological processes, including cell survival and metabolism, and gene expression, the researchers theorized. The changes in gene expression then lead to some of the key markers seen in Alzheimer's patients: tau protein tangles and inflammation.
It's important to point out that this hypothesis is based on a scientific model using available data—not something that has been tested and proven.
What are "stress granules" and how are they connected to Alzheimer's?
As the paper explains, "stress granules" are basically clumps of proteins and RNA (a nucleic acid in cells with similar structures to DNA) that form when a cell is under stress.
These clumps form temporarily in the cell in response to stress in the environment. They help the cell press "pause" on normal functioning until it recovers.
Under normal circumstances, these "stress granules" actually serve an important purpose: helping protect the cell, then dissolving when the stressful event is over. But in people with Alzheimer's disease, the granules seem don't dissolve, which keeps essential molecules from moving in and out of the cell's nucleus as they normally would, explains study co-author Carol Huseby, PhD, assistant professor in the Banner Neurodegenerative Disease Research Center at Arizona State University.
'If stress is chronic, the cell's normal business is affected, such as making new molecules, transporting molecules, and recycling of molecules,' she says. That can eventually harm the cell and could lead to the progression of Alzheimer's disease.
It's important to note that the scientists are talking about biological stress here, not psychological. "The 'stress' causing these granules in biology is different from emotional stress," says Michal Schnaider Beeri, PhD, director of the Herbert and Jacqueline Krieger Klein Alzheimer's Research Center at Rutgers Robert Wood Johnson Medical School. "Biological stress refers to various challenges to the cell. Emotional stress, while it can have physical effects, is a psychological experience. While both types of stress can impact health, they operate through very different mechanisms at the cellular level."
There are a lot of potential stressors that cause these granules to form, including exposure to toxins, traumatic brain injury, viruses, oxidative stress, and genetic mutations, Huseby says. Getting sick or being exposed to things like pollution and pesticides can also put stress on your body—and your cells.
While this study suggests there could be a link between cell stress and Alzheimer's, there is also an established link between psychological stress and the disease.
'Chronic stress increases cortisol levels, which can shrink the hippocampus,' says Verna Porter, MD, is a neurologist and director of the Dementia, Alzheimer's Disease, and Neurocognitive Disorders at Pacific Neuroscience Institute at Providence Saint John's Health Center in Santa Monica, CA. (The hippocampus is involved in learning and memory.) Having anxiety and depression is also linked with a higher risk of dementia, she points out.
Overall, 'all indications point to cell stress as occurring early in disease,' Huseby says. 'The key to understanding Alzheimer's disease is to understand when the disease is first detected before too many neurons are lost,' she continues. 'This information will lead to the most effective early treatments for Alzheimer's disease.'
Again, there's a lot experts still don't know about why some people end up developing Alzheimer's disease. And this study is just one hypothesis. But taking these steps may help lower your risk, according to the Alzheimer's Association:
Exercise regularly
Quit smoking (or don't pick up the habit!)
Manage high blood pressure and diabetes
Eat a heart-healthy diet
Try to maintain a healthy weight
Stay socially connected
Stimulate your brain with new activities and challenges
Doing what you can to manage stress levels, like practicing mindfulness, meditating, or doing relaxing hobbies, may also help, Dr. Porter says.
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