Scientists at Cedars-Sinai have discovered important changes in the retina that may help detect Alzheimer’s disease earlier. Their research shows that the retina, which is directly connected to the brain, can reveal signs of the disease long before major cognitive decline occurs. This finding could lead to new, non-invasive ways to diagnose and monitor Alzheimer’s disease.
Alzheimer’s disease is a progressive condition that damages memory and thinking skills. It has no single test for diagnosis, and by the time symptoms become obvious, much of the brain damage has already occurred. This study provides new evidence that examining the retina could help identify the disease at an earlier stage.
Over 14 years, the researchers analyzed retina and brain tissue samples from 86 human donors. They compared samples from people with normal brain function to those with mild cognitive impairment (an early stage of Alzheimer’s) and those with more advanced Alzheimer’s disease.
The team studied the proteins, cells, and structural changes in these retinas and linked them to brain changes and cognitive function.
One of the biggest discoveries was the buildup of amyloid beta 42, a toxic protein that is known to play a major role in Alzheimer’s disease. This protein accumulated in the ganglion cells of the retina, similar to how it collects in the brain. The researchers also found:
- Higher numbers of immune cells called astrocytes and microglia surrounding amyloid beta plaques.
- Up to 80% fewer microglial cells that normally help clear out amyloid beta, making it harder for the brain and retina to remove harmful proteins.
- Increased inflammation and cell death in the retina, which mirrors the damage seen in the brain.
These changes were found in people who had very mild or no cognitive symptoms, suggesting that the retina could act as an early warning sign for Alzheimer’s. The study also found that retinal changes matched brain damage in areas responsible for memory, navigation, and time perception.
The researchers believe these findings could help doctors develop new tests and treatments for Alzheimer’s. If the retina can provide early signs of the disease, it may allow for earlier interventions to slow or prevent cognitive decline.
The study was led by Dr. Yosef Koronyo and published in Acta Neuropathologica.
If you care about dementia, please read studies about low choline intake linked to higher dementia risk, and how eating nuts can affect your cognitive ability.
For more information about brain health, please see recent studies that blueberry supplements may prevent cognitive decline, and results showing higher magnesium intake could help benefit brain health.
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