Scientists uncover 'root cause' of Alzheimer's disease in breakthrough study

Alzheimer's disease is one of the top ten leading causes of death in the United States. While there are medicines to manage symptoms of the neurodegenerative disease, there is no specific cure for it yet. It is estimated that nearly 7 million Americans are living with Alzheimer's and by the year 2050, this number may rise to nearly 13 million.
Although many people tend to mistake Alzheimer's disease for dementia, in fact - both are not the same. However, it is the most common type of dementia. Dementia is a general term for a decline in mental ability, while Alzheimer's is a specific brain disease.
There is no definitive cause of Alzheimer's disease pinpointed by scientists yet, but many of the risk factors include genetics, age, environment, and lifestyle reasons could lead to its development.
Maintaining a healthy lifestyle like eating a balanced diet, regular exercise, sleeping for sufficient hours, and socializing can help prevent the disease.

In a new research published in the journal Alzheimer’s & Dementia scientists have found a single cause of development of Alzheimer’s disease and that is the formation of stress granules.
While the hypothesis challenges everything that the experts have so far believed, but gives hope that the knowledge of the root cause can help with the breakthrough in Alzheimer's treatment.

The study took into account existing studies, which included 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.
Stress granules are described as clumps of proteins and RNA (a nucleic acid in cells with similar structures to DNA) that form when a cell is under stress.
Researchers discovered how these "stress granules" interrupt molecule movement between a cell's nucleus and its cytoplasm. This messes with a range of other important biological processes too, including cell survival and metabolism, and gene expression, said the researchers.
The changes in gene expression further lead to some of the key markers seen in Alzheimer's patients - tau protein tangles and inflammation.
These stress granules form temporarily in the cell in response to stress in the environment. They help the cell press "pause" on normal functioning until it recovers. While stress granules typically help protect the cell, in individuals with Alzheimer’s disease, they fail to dissolve, preventing essential molecules from moving in and out of the cell’s nucleus as they should, explains study co-author Carol Huseby, PhD, assistant professor at 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.
The stress referred to here is biological stress and 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."
Scientists say exposure to toxins, traumatic brain injury, viruses, oxidative stress and genetic mutations can lead to stress granules formation. Getting sick or exposure to pollution and pesticides can also put stress on the biological processes.
Alzheimer's disease is normally seen in people over 65 years old and as the disease progresses, memory problems worse. It is common for people to forget recent events, names, or where things are. Having trouble finding words, reading, or writing is also related to Alzheimer's disease.
As the condition advances, individuals may struggle with decision-making, confusion, and changes in personality or behavior. Early diagnosis and proper care can help manage symptoms and improve quality of life.
Common causes of Alzheimer’s disease include genetic factors, aging, and abnormal protein buildup in the brain (amyloid plaques and tau tangles). Lifestyle factors like poor diet, lack of exercise, and cardiovascular issues may also contribute. Chronic inflammation and oxidative stress can further increase the risk.