Abstract
Background
Carrying the Apolipoprotein (APOE) ε4 allele lowers age of onset and increases Alzheimer's disease (AD) risk. Neuropathological findings suggest a mixed etiology in many AD patients, and vascular pathology is common.
Objective
This study tested the interactive effect of APOE status and multiple vascular comorbidities on white matter (WM) microstructure in aging and early AD.
Methods
195 participants from the VPH-DARE@IT dataset were stratified in low/high vascular burden based on the Framingham Risk Score (BMI version). Tract-based spatial statistics was used for WM analyses.
Results
There was a main effect of APOE, with APOE ɛ4 carriers having higher fractional anisotropy (FA) and lower axial diffusivity (AxD), mean diffusivity (MD), and radial diffusivity (RD) than non-carriers. There was a main effect of vascular burden with lower FA and higher AxD, MD, and RD in the high-burden than the low-burden group. A significant interaction between APOE genotype and vascular burden was also found for all diffusion indices. Post-hoc comparisons revealed lower left hemisphere WM integrity when comparing the low risk group (i.e., non-carriers low burden) to intermediate risk groups (i.e., non-carriers high burden or ɛ4 carriers low burden). The contrasts between the two intermediate risk groups showed altered WM integrity bilaterally. Only the non-carriers high burden showed greater alterations in WM integrity when compared with the high risk group (i.e., ɛ4 carriers high burden) mainly in right hemisphere tracts.
Conclusions
These findings indicate an interactive effect of a risk gene and vascular comorbidities on WM integrity in aging and early AD.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
