December 12, 2017
Researchers are getting closer to developing an eye scan to detect Alzheimer’s disease at its earliest stages, before symptoms become prominent. The simple tests could one day offer an inexpensive way to detect impending Alzheimer’s or track its progress.
Early detection, followed by early treatment, may offer the best hope for effectively treating Alzheimer’s and slowing or preventing its progression, experts say. Current drugs may offer mild relief for some patients but do nothing to modify the downward course of the disease, in part because of the advanced state of the disease.
The eye scan in development, described in a paper in the journal JCI Insight, uses optical scans of the retina, the layer of cells at the back of the eye. The scans look for the buildup of beta-amyloid, a toxic protein that is a hallmark of Alzheimer’s disease. In Alzheimer’s disease, beta-amyloid levels build up and clumps together to form plaques in the brain. The same process may also create beta-amyloid deposits in the eyes as well, the new study shows.
For the study, researchers at Cedars-Sinai Medical Center in Los Angeles used an imaging technique from the company NeuroVision Imaging that had first been tested in mice. The study looked at 16 patients with Alzheimer’s and compared them with healthy peers. The researchers also examined the eyes and brains of several dozen volunteers with Alzheimer’s who had died.
The researchers found that those with Alzheimer’s were nearly five-times more likely than those without the disease to have plaques in their eyes, which appeared as brown spots on the scans. Buildup of beta-amyloid in the eye also correlated with plaque buildup in the brain.
“This is the first study demonstrating the potential to image and quantify retinal findings related to beta-amyloid plaques noninvasively in living patients using a retinal scan with high resolution,” said Maya Koronyo-Hamaoui, an associate professor of Neurosurgery and Biomedical Sciences at Cedars-Sinai and the leading author of the study. “Findings from this study strongly suggest that retinal imaging can serve as a surrogate biomarker to investigate and monitor Alzheimer’s disease.”
Beta-amyloid deposits can currently be detected to some degree in the brains of those with Alzheimer’s using PET scans and spinal fluid tests. But those tests are expensive and require fairly elaborate preparation and execution. An effective eye scan would be an easier way to monitor Alzheimer’s progression.
“The retina may offer a unique opportunity for us to easily and conveniently detect and monitor Alzheimer’s disease,” said Dr. Keith Black, the chair of the Department of Neurosurgery at Cedars-Sinai. “We know that Alzheimer’s begins as many as 10 or 20 years before cognitive decline becomes evident, and we believe that potential treatments may be more effective if they can be started early in the process. “
The study was a preliminary one in a small number of patients. More testing is needed to verify the findings. But they suggest that an eye scan could one day be effective in detecting the earliest stages of Alzheimer’s, before memory loss and thinking problems become evident. And early detection may offer the best hope for effective treatment.
“Our hope is that eventually the investigational eye scan will be used as a screening device to detect the disease early enough to intervene and change the course of the disorder with medications and lifestyle changes,” said Dr. Black.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Yosef Koronyo, Keith L. Black, Maya Koronyo-Hamaoui, et al: Retinal amyloid pathology and proof-of-concept imaging trial in Alzheimer’s disease. JCI Insight, Aug. 17, 2017