It may one day be possible to detect Alzheimer disease (AD) early and monitor its development or response to treatment with an eye scan. The same research team that in 2011 provided evidence that amyloid-β plaques in retinas of deceased patients with AD correlated with plaque burden in their brains has now shown in a small, proof-of-concept trial that these protein deposits can be detected in the retinas of living patients.
“We were able to detect increased signal of beta-amyloid pathology in the retina of AD patients, representing the first ability to noninvasively image beta-amyloid deposits and quantify their amount in the retina,” said researcher Maya Koronyo-Hamaoui, PhD, an associate professor in neurosurgery and biomedical sciences at the Cedars-Sinai Medical Center in Los Angeles.
The researchers developed a retinal amyloid index (RAI), a value that denotes amyloid burden in the retina, using a modified curcumin fluorochrome and a modified scanning laser ophthalmoscope. RAI scores were on average 2.1-fold higher in patients with AD than in cognitively normal control subjects. The findings were published in JCI Insight.
The method is now in different stages of clinical trials in the United States, Europe, and Australia. “We are testing larger cohorts of living patients for the possible relationship between retinal amyloid pathology and the gold standard amyloid-PET brain imaging and other AD biomarkers,” Koronyo-Hamaoui said.
As studies suggest the level of amyloid burden does not always correlate with AD, further research is needed to validate methods that propose using amyloid-β as a diagnostic biomarker for the disease.
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Abbasi J. A Retinal Scan for Alzheimer Disease. JAMA. 2017;318(14):1314. doi:10.1001/jama.2017.15192