Differences in resting-state brain networks and gray matter between APOE ε2 and APOE ε4 carriers in non-dementia elderly

Zhiyuan Wang; Jing Pang; Ruizhi Zhou; Jianjiao Qi; Xianglong Shi; Bin Han; Xu Man; Qingqing Wang; Jinping Sun

doi:10.3389/fpsyt.2023.1197987

Differences in resting-state brain networks and gray matter between APOE ε2 and APOE ε4 carriers in non-dementia elderly

Front Psychiatry. 2023 Aug 10:14:1197987. doi: 10.3389/fpsyt.2023.1197987. eCollection 2023.

Authors

Zhiyuan Wang¹, Jing Pang², Ruizhi Zhou², Jianjiao Qi³, Xianglong Shi², Bin Han⁴, Xu Man¹, Qingqing Wang³, Jinping Sun³

Affiliations

¹ Institute of Integrative Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China.
² Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, China.
³ Department of Emergency Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China.
⁴ Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China.

Abstract

Background: Apolipoprotein E (APOE) ε2 and APOE ε4 are the most distinct alleles among the three APOE alleles, both structurally and functionally. However, differences in cognition, brain function, and brain structure between the two alleles have not been comprehensively reported in the literature, especially in non-demented elderly individuals.

Methods: A neuropsychological test battery was used to evaluate the differences in cognitive performance in five cognitive domains. Independent component analysis (ICA) and voxel-based morphometry (VBM) were used separately to analyze resting-state functional magnetic resonance imaging (rs-fMRI) data and the structure MRI data between the two groups. Finally, correlations between differential brain regions and neuropsychological tests were calculated.

Results: APOE ε2 carriers had better cognitive performance in general cognitive, memory, attention, and executive function than APOE ε4 carriers (all p < 0.05). In ICA analyses of rs-fMRI data, the difference in the resting-state functional connectivity (rsFC) between two groups is shown in 7 brain networks. In addition, VBM analyses of the T1-weighted image revealed that APOE ε2 carriers had a larger thalamus and right postcentral gyrus volume and a smaller bilateral putamen volume than APOE ε4 carriers. Finally, differences in brain function and structure may be might be the reason that APOE ε2 carriers are better than APOE ε4 carriers in cognitive performance.

Conclusion: These findings suggest that there are significant differences in brain function and structure between APOE ε2 carriers and APOE ε4 carriers, and these significant differences are closely related to their cognitive performance.

Keywords: APOE ε2; APOE ε4; independent component analysis; non-dementia elderly; resting-state functional magnetic resonance imaging; voxel-based morphometry.