Retinal maculo‐papillary OCT and hippocampal and others cerebral areas MRI in subjects with a family history of Alzheimer's disease and allelic characterization for ApoE ɛ4

Abstract

AbstractPurpose: In addition to advanced age, genetic inheritance is another predisposing factor for the development of Alzheimer's disease (AD). Retinal changes already exist in preclinical stages, so the aim of this study was to analyse possible retinal changes in subjects at high risk of developing AD using OCT and correlate them with brain areas analysed by magnetic resonance imaging (MRI).Methods: Macular and peripapillary OCT and brain MRI were performed in 64 cognitively healthy subjects. 30 controls were subjects with no family history of AD and carrying no ApoE ɛ4 allele (FH− ApoE ɛ4−), while 34 subjects had an affected first‐degree relative and at least one ɛ4 allele (FH+ ApoE ɛ4+).Results: We observed in the FH+ ApoE ɛ4+ group compared to the control group a significant volume reduction in the following macular areas: (i) macular RNFL (mRNFL), (ii) inner plexiform layer (IPL); (iii) inner nuclear layer (INL) and (iv) outer plexiform layer (OPL). Moreover, in the FH+ ApoE ɛ4+ group the retinal sectors that showed a statistically significant decrease in volume correlated with brain areas that are affected in the early stages of AD, such as the lingual gyrus, the hippocampal region and the entorhinal cortex. In the same group, no statistically significant changes in thickness were found in the peripapillary retinal nerve fibre layer (pRNFL) compared to the control group. However, correlations of these sectors with brain areas involved in this pathology were also found.Conclusions: In cognitively healthy subjects at high genetic risk of developing sporadic forms of AD, there are significant correlations between the changes observed in the retina and brain areas closely related to AD, such as the lingual gyrus, the hippocampal area and the entorhinal cortex.