Changes in the retina may be linked to parts of the brain in healthy people with Alzheimer’s disease

Summary: In cognitively healthy individuals at genetic risk for Alzheimer’s disease, retinal changes are associated with changes in the entorhinal cortex, hippocampus, and lingual gyrus. Changes in the retina can be used to track changes in brain structures associated with Alzheimer’s disease in people with genetic risk factors, researchers say.

A source: MCU

In subjects who were cognitively healthy but had a high genetic risk for Alzheimer’s disease, connections between the retina and various brain structures affected by the disease, such as the entorhinal cortex, lingual gyrus, and hippocampus, were demonstrated.

This is the main conclusion of a study led by the Ramon Castroviejo Ophthalmic Research Institute (IIORC) of the Complutense University of Madrid (UCM).

The novelty of the study published in Alzheimer’s Research and Therapy, It is the first to study the relationship between the areas of the retina most affected in Alzheimer’s disease and the brain structures.

“This means that the retina, which is an easily accessible tissue, can provide information about the state of the brain and the changes that occur in it,” notes IORC researcher and lead author of the paper Ines López-Cuenca.

The San Carlos Clinical Hospital and the Technical University of Madrid participated in the study with UCM as part of the COGDEM study.

Next step: visual inspection

A group of patients whose father or mother suffered from Alzheimer’s disease and had a mutation in their ApoE ɛ4 gene was included in the study.

A group of patients whose father or mother suffered from Alzheimer’s disease and had a mutation in their ApoE ɛ4 gene was included in the study. Image is in the public domain

The IORC provided them with ophthalmological examinations, including optical coherence tomography (OCT). These tests were then compared with magnetic resonance imaging (MRI) tests performed by the Neurological Service of the San Carlos University Clinical Hospital in Madrid, which measured more than 20 different brain structures from both hemispheres.

“We saw that these participants were showing changes in some areas of the retina as measured by OCT, while brain MRI was still normal,” says López-Cuenca.

As with the structure of the retina, the UCM team is collecting data from patients’ perspectives to learn how the visual network functions during these phases of the disease.

This is Alzheimer’s research news

Author: Maria Milan
A source: MCU
The connection: Maria Milan – MCU
Photo: Image is in the public domain

Original research: Open access.
“Connectivity between retinal layers and brain regions in asymptomatic first-degree relatives of sporadic forms of Alzheimer’s disease: an exploratory analysis” Ines López-Cuenca et al. Alzheimer’s Research and Therapy

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It shows the researcher and the test subject

Abstract

Connectivity between retinal layers and brain regions in asymptomatic first-degree relatives of sporadic Alzheimer’s disease: an exploratory analysis

Background

The two main genetic risk factors for sporadic Alzheimer’s disease (AD) are family history and the ɛ4 allele of apolipoprotein E. The brain and retina are part of the central nervous system and share pathophysiological mechanisms in AD.

Methods

We conducted a cross-over study with 30 participants without a family history of ApoE ɛ4 (ApoE ɛ4−) as a control group and 34 participants with familial AD (FH+) and carriers. from at least one ɛ4 allele (ApoE ɛ4+). We analyzed the association of macular volume of retinal layers and peripapillary retinal nerve fiber layer (pRNFL) thickness measured by optical coherence tomography (OCT) with brain area parameters measured by magnetic resonance imaging (MRI) in participants at high genetic risk. developing AD (FH+ ApoE ɛ4+).

Results

We observed a significant reduction in some macular regions of (i) macular RNFL (mRNFL), (ii) inner plexiform layer (IPL), (iii) inner nuclear layer (INL) in the FH + ApoE ɛ4 + group compared to the control group. , and (iv) outer plexiform layer (OPL). Furthermore, in the FH+ ApoE ɛ4+ group, retinal sectors showing statistically significant volume reduction are associated with brain regions affected in the early stages of AD. In the same group, peripapillary retinal nerve fiber layer (pRNFL) did not show statistically significant changes in thickness compared to the control group. However, these sectors have also been found to be associated with brain regions involved in the disease.

Conclusions

Cognitively healthy participants have a high genetic risk of developing sporadic forms of AD, with significant associations with retinal changes in the entorhinal cortex, lingual gyrus, and hippocampus.

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