Virginia Tech researchers find that muscle function could lead to early Alzheimer’s diagnosis

It doesn’t take much thought to pick up a pencil, open a door, or even type this sentence.

The process happens almost instantaneously. But in that split second, the brain sends a signal along specialized nerves, or motor nerves, telling the receiving muscle what to do, also known as contraction.

Each contraction produces a given amount of force — are you yanking the door open or tapping the keyboard?

But sometimes, the brain or the associated systems don’t operate the way they should, even for simple tasks.

One disease that affects the underlying nature of the brain is Alzheimer’s disease, which develops over time, sometimes slowly or even decades before diagnosis.

Researchers from Virginia Tech's College of Agriculture and Life Sciences found that declining skeletal muscle health in a model of Alzheimer’s disease was caused by impaired peripheral nerve function. That might be an early indicator — before mental impairment or clinical diagnosis — that could allow for treatment or interventions to delay or prevent Alzheimer’s disease.

“Alzheimer’s is extremely hard to identify at a preclinical level because we don’t have a good understanding how the disease develops before cognition is impaired,” said Joshua Drake, assistant professor in the Department of Human Nutrition, Foods, and Exercise and principal investigator on the project. “But what we can look at are the ways the body changes before diagnosis and use that to identify people that could be at risk.”

The research, done in collaboration with the University of Arkansas, was recently published in Function, an American Physiological Society journal, and was funded by the National Institutes of Health.

The study has two major takeaways, according to Drake.

• The researchers are adding to the argument that Alzheimer’s disease is a systemic pathology and it likely has broader implications for the entire body.
• It could lead to identifying people with the disease earlier and potentially improve their quality of life.

Additioanlly, early changes in communication to skeletal muscle in Alzheimer’s disease may alter how muscles adapt to lifestyle interventions, such as exercise.

“We’re building off a body of literature that’s been out there in the clinical space showing that people who develop Alzheimer’s disease have had profound skeletal muscle loss before cognitive symptoms,” Drake said.

What the research team did was zero in on why this may be the case and that the issues are not a problem with the muscle itself, but rather a change in the way the brain communicates with the muscles through the nervous system. This also changes the way muscles adapt to exercise.

“This gives us a potential avenue to identify someone that might be at risk,” Drake said. “Can we measure nerve function in a peripheral limb as an indicator for increased risk of Alzheimer’s disease? That’s what our findings suggest.”

Additionally, Siobhan Craige, assistant professor in the Department of Human Nutrition, Foods, and Exercise; Robert Grange, professor in the department and the director of the Metabolism Core at Virginia Tech; and Steve Poelzing, a professor in the Fralin Biomedical Research Institute at VTC, contributed to the research. Matthew H. Brisendine, a Ph.D. candidate in human nutrition, foods, and exercise was the lead author.