Eye Exam May Aid in Early Alzheimer's Detection

A recent study offers important insight into how Alzheimer’s disease begins within the brain. The innovative findings suggest screening for the disease could become a part of annual exams.

University of Texas, Galveston (UTMB) researchers found a relationship between inflammation, a toxic protein and the onset of the disease. The study also identified a way that doctors can detect early signs of Alzheimer’s by looking at the back of patients’ eyes.

“Early detection of Alzheimer’s warning signs would allow for early intervention and prevention of neurodegeneration before major brain cell loss and cognitive decline occurs,” said lead author Ashley Nilson, a neuroscience graduate student.

“Using the retina for detecting AD and other neurodegenerative diseases would be non-invasive, inexpensive, and could become a part of a normal screening done at patient checkups.”

UTMB researchers have previously found evidence that a toxic form of tau protein may underlie the early stages of Alzheimer’s. Brain cells depend on tau protein to form highways for the cell to receive nutrients and get rid of waste.

In some neurodegenerative diseases like Alzheimer’s, the tau protein changes into a toxic form called tau oligomers and begins clumping into neurofibrillary tangles. When this happens, molecular nutrients can no longer move to where they are needed and the oligomers produce toxic effects leading to the eventual death of the brain cells.

Emerging research suggests inflammation within the brain plays an important role in Alzheimer’s development and progression. Inflammation and loss of connections between nerves within the brain happen before the formation of the tangles that are characteristic of this disease.

It’s possible that the tau oligomers may be responsible for this inflammation, explain the researchers.

In the new study, UTMB researchers detailed the relationship between inflammation, toxic tau and Alzheimer’s onset. They accomplished this by performing systematic analyses of brain and examinations of retina samples from people with Alzheimer’s and a mouse model of Alzheimer’s.

Their results, as published in the Journal of Alzheimer’s Disease, suggests that the toxic tau may induce inflammation in Alzheimer’s. The toxic tau spreads between connected brain regions, which may initiate inflammation in these new regions. The vicious cycle of toxic tau, inflammation and cell death spreads throughout the brain over time.

A positive finding is the discovery that an eye exam can detect retina tissue that shows evidence of toxic tau and inflammation early in the disease process.

This early detection of degeneration of nerve cells due to chronic inflammation induced by the tau oligomers may allow therapeutic medications to reduce inflammation and therefore minimize the damage of Alzheimer’s and related diseases, said senior author Dr. Rakez Kayed, associate professor in the UTMB Department of Neurology.

Source: University of Texas, Galveston