Changes in the retina can be linked to parts of the brain of healthy subjects at risk of Alzheimer’s

UCC-UCM, 26 July 2022. In subjects who are cognitively healthy but have a high genetic risk of developing Alzheimer’s, correlations have been demonstrated between the retina and various brain structures which suffer changes as a result of the disease, such as the entorhinal cortex, the lingual gyrus and the hippocampus. This is the main conclusion of the research led by the Ramón Castroviejo Institute for Ophthalmological Research (IIORC) of the Complutense University of Madrid (UCM).

The novelty of the study, published in Alzheimer's Research & Therapy, lies in the fact that for the first time it has examined the corelations between the retinal areas and the cerebral structures most affected in Alzheimer’s, a disease in which up to two decades can pass before the first appearance of symptoms.

“This means that the retina, which is an easily accessible tissue, may provide information on the state of the brain and the changes taking place in it”, notes Inés López-Cuenca, IIORC researcher and lead author of the work.

Participating in the research with UCM were the San Carlos Clinical Hospital and the Technical University of Madrid, as part of a COGDEM study.

Next step: studying vision

To carry out the research, a group of patients was included whose fathers or mothers suffered from Alzheimer’s and who had a mutation in their gene ApoE ɛ4, which predisposes them to suffer from the disease.

The IIORC gave them ophthalmological examinations, including Optical Coherence Tomography (OCT). These tests were then compared with those of the magnetic resonance imaging (MRI) carried out by the Neurological Service of the San Carlos University Clinical Hospital of Madrid, and resulting in measurements of more than 20 different brain structures from both hemispheres.

“We have seen that these participants already show changes in some areas of the retina measured with OCT, while the brain MRI is still normal”, says López-Cuenca.

As well as the structure of the retina, the UCM group is collecting data on patients’ eyesight, to discover how the visual network operates in these phases of the disease which are still asymptomatic.