New Study Suggests One Singular Cause For Alzheimer’s Disease

Alzheimer’s disease continues to puzzle scientists who not only want to identify the exact cause of the disease but discover a cure for this neurodegenerative disorder. So far, investigations have focused on age, genetic changes, the buildup of abnormal tau and amyloid proteins, and lifestyle as causes of Alzheimer’s. While these are key factors, scientists say they still do not fully understand the root cause of Alzheimer’s and why some people develop the disease and others do not.

Researchers at Arizona State University (ASU) believe they have found the answer, even though it vastly differs from the views of other researchers and previous studies. In their new study, the ASU team suggests there is a single culprit behind Alzheimer’s disease: Stress granules.

According to Michael Schnaider Beeri, director of the Herbert and Jacqueline Krieger Klein Alzheimer’s Research Center at Rutgers Robert Wood Johnson Medical School, the “stress” is biological, not emotional.

“Biological stress refers to various challenges to the cell,” Beeri explained to Women’s Health Magazine. “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.”

The ASU research team explains that stress granules are clumps of proteins and RNA (a type of nucleic acid in cells with structures similar to DNA) that form when a cell is under stress. They cause the cell to temporarily stop normal functions until it recovers. The stress granules usually protect the cell during stressful conditions and dissolve after the event is over.

However, the granules don’t seem to dissolve in people with Alzheimer’s disease and prevent essential molecules from moving in and out of the cell’s nucleus as they normally would, explains Carol Huseby, the study’s co-author and an 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,” Huseby said. This can ultimately damage the cells and may contribute to the progression of Alzheimer’s disease.

According to Huseby, exposure to toxins, traumatic brain injury, viruses, oxidative stress, and genetic mutations are among the many potential stressors that cause stress granules to form. Getting sick or exposed to pollutants and pesticides can also stress the body and cells.

The ASU Study

In their new study, the ASU team members analyzed existing research and data, including a 2022 study on Alzheimer’s progression, and proposed that “stress granules” may be the reason Alzheimer’s disease develops in some people and not others.

Researchers examined how stress granules interfere with the movement of molecules between a cell’s nucleus (the central part containing genetic material) and its cytoplasm (the jelly-like substance that surrounds the nucleus where essential chemical processes take place).

The ASU team compared the disruption of the nucleus-to-cytoplasm “transit system” to a “clogged highway preventing the movement of critical goods, leaving resources stuck, and causing chaos on both sides of the communication hub.”

The researchers theorized that the disruptions interfere with many essential biological processes, including cell survival, metabolism, and gene expression—the process by which genes produce the proteins essential for cell function. Changes in gene expression can lead to the development of tau protein tangles and inflammation, two of the key markers seen in Alzheimer’s patients.

Paul Coleman, a research professor at ASU’s Banner Neurodegenerative Disease Research Center, who led the study, said in a statement: “Our proposal, focusing on the breakdown of communication between the nucleus and cytoplasm leading to massive disruptions in gene expression, offers a plausible framework to comprehensively understand the mechanisms driving this complex disease. Studying these early manifestations of Alzheimer’s could pave the way for innovative approaches to diagnosis, treatment, and prevention, addressing the disease at its roots.”

The research was published in February in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

Psychological Stress Can Also Lead to Alzheimer’s

While the ASU study suggests a possible link between cell stress and Alzheimer’s, the relationship between psychological stress and Alzheimer’s has already been established.

“Chronic stress increases cortisol levels, which can shrink the hippocampus,” Dr. Verna Porter, 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, told Women’s Health Magazine. The hippocampus is involved in learning and memory. Dr. Porter noted that anxiety and depression are linked to a higher risk of dementia.

Overall, “all indications point to cell stress as occurring early in the disease,” Huseby said. “The key to understanding Alzheimer’s disease is to understand when the disease is first detected before too many neurons are lost. This information will lead to the most effective early treatments for Alzheimer’s disease.”

How To Lower Your Risk for Alzheimer’s

Nearly seven million people in the United States aged 65 and older live with Alzheimer’s disease, the most common form of dementia, according to the Alzheimer’s Association. Alzheimer’s is a progressive brain disorder that causes memory loss, confusion, disorientation, and other cognitive decline. The symptoms worsen as the disease progresses, and Alzheimer’s can severely disrupt an individual’s daily living activities as the disease’s symptoms worsen.

The exact cause of Alzheimer’s is not known, but existing research suggests age, genetics, and brain changes, including the buildup of abnormal proteins in the brain, can contribute to the development of the disease.

As the disease worsens, individuals experience more cognitive decline and a decreased capacity to manage their daily activities, such as bathing, eating, and dressing.

According to the Alzheimer’s Association, there are steps to take to lower the risk of developing the disease, such as: