Various Retinal Changes May Be a Biomarker for Alzheimer’s Disease

In a study published in Acta Neuropathologica, clinical researchers examined the link between specific retinal changes and mild cognitive impairment in Alzheimer’s disease patients. Based on the data in the study, researchers predict that retinal changes may be a biomarker for Alzheimer’s.

“Our study is the first to provide in-depth analyses of the protein profiles and the molecular, cellular, and structural effects of Alzheimer’s disease in the human retina and how they correspond with changes in the brain and cognitive function,” said Maya Koronyo-Hamaoui, PhD, professor of Neurosurgery, Neurology, and Biomedical Sciences at Cedars-Sinai and senior author of the study, in the press release.

According to the WHO, roughly 55 million people globally have dementia, with 60–80% of dementia patients having an Alzheimer’s disease diagnosis.

The diagnosis process for Alzheimer’s disease and other types of dementia can be complicated. Standard diagnostic tools may include neurocognitive tests, brain scans, blood tests, and other devices.

As researchers continue to understand Alzheimer’s, they constantly look for new and effective screening tools. Data shows that early diagnosis often correlates with extended lifespans, slower disease progression, and improved quality of life.

In a 2022 interview with LifeSciencesIntelligence, Steven R. Smith, MD, Chief Scientific Officer at Advent Health, explained that early diagnosis of Alzheimer’s improves patient preparedness for disease progression, allows patients to make lifestyle and medication changes to slow disease progression, and results in long-term savings.

The recent study led by investigators at Cedars-Sinai may have helped identify additional Alzheimer’s biomarkers for early diagnostics. The study looked at a cohort of 86 subjects who died at various stages of cognition. Clinicians looked at molecular, cellular, and structural factors that could be detected in the retina and compared them with dementia progression.

The first factor the investigators looked at was the presence of specific proteins in the retina. According to the publication, a qualitative analysis of the superior and inferior temporal retinas showed that patients with mild cognitive impairment or Alzheimer’s disease had higher levels of amyloid β-protein (Aβ42) forms and novel intraneuronal Aβ oligomers (AβOi).

Beyond the higher levels of β-amyloid plaques, the researchers also noted that astrocytes and microglia were packed around these plaques; however, microglia were not effectively clearing the proteins from the retina and brain.

“These findings give us a deeper understanding of the effects of Alzheimer’s disease on the retina,” said Keith L. Black, MD, chair of the Department of Neurosurgery and the Ruth and Lawrence Harvey Chair in Neuroscience at Cedars-Sinai and a co-author of the study, in the press release. “Because these changes correspond with changes in the brain and can be detected in the earliest stages of impairment, they may lead us to new diagnostics for Alzheimer’s disease and a means to evaluate new forms of treatment.”