Blood vessel abnormalities in the eye are a major factor in the progression of Alzheimer’s disease, according to research from Cedars-Sinai investigators published in the peer-reviewed journal Alzheimer's & Dementia: The Journal of the Alzheimer's Association. These changes correspond to changes in the brain, offering a new possibility for early diagnosis.
Investigators compared blood vessels in retinas collected from 24 human donors with Alzheimer’s disease, 10 donors with mild cognitive impairment and 27 with normal cognition.
In patients with Alzheimer’s disease and mild cognitive impairment, they found one of the earliest signs of Alzheimer’s disease to date: disruption of the blood-retinal barrier, where tightly joined cells prevent harmful substances from entering the retinal tissue.
Damage to the blood-retinal barrier was strongly associated with a condition called cerebral amyloid angiopathy (CAA)—the accumulation of amyloid proteins in small blood vessels—and other vascular disease in the brain.
The study also found that deposits of a protein called amyloid beta 40 accumulated in the retinal arteries of Alzheimer’s disease patients, making the arteries stiff, disrupting blood flow and preventing the arteries from clearing harmful substances from the retina.
