Abstract Details

Title Protective Effect of APOE-e2 on Cortical Thickness and Volume in a Cerebrovascular Registry

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) S36 - Cerebrovascular Disease and Interventional Neurology: Basic and Translational Science (2:48 PM-3:00 PM)

Poster/Presentation
Number 010

Background Studies have shown a negative association of APOE-ε4 allele with regional cortical thickness and volume. The role of the APOE-ε3 allele has been considered neutral in several studies. The protective role of APOE-ε2 against cortical thinning has not been well established.

Objective To compare cortical thickness across APOE genotypes, and to assess the potential protective effect of APOE2 on brain cortical thinning and grey matter volume.

Design/Methods From a biomarker cerebrovascular registry, 187 individuals with APOE testing and MRI brain from 2010 to 2020 were included. APOE genotype tested were ε2ε2, ε2ε3, ε2ε4, ε3ε3, ε3ε4, ε4ε4, stratified to APOE-ε2 carrier or APOE-ε2 non-carrier. Cortical thickness, cortical volume and gray matter volume were estimated on T1-weighted images using FreeSurfer. Measures of brain atrophy were compared across APOE genotypes, and between ε2 vs non-ε2 allele carriers. Mini-Mental Status Examination (MMSE) were compared between groups.

Results In our cohort (n=187), mean age was 60±16 years and 55.4% were female. Of the APOE genotypes, 18.5% were APOE-ε2 carriers (ε2ε2 3, ε2ε3 33), 81.5% were APOE-ε2 non-carriers (ε3ε3 114, ε3ε4 43, ε4ε4 2). Compared to ε2 non-carriers, ε2 carriers were less likely to have hypertension, diabetes, coronary artery disease, and had higher LDL (p<0.05). Across APOE genotypes, cortex was thickest in ε2ε2 (2.35 mm) and thinnest in ε4ε4 (1.92 mm) (p = 0.0137). APOE-ε2 carriers had significantly thicker cortex (2.13 mm vs 1.96 mm, p=0.001), larger cortical volume (313.26 cm3 vs 266.09 cm3, p=<0.001) and grey matter volumes (459.93 cm3 vs 411.01 cm3, p=0.001), compared to ε2 non-carriers. There was no difference in MMSE between ε2carriers vs non-carriers (24.4 vs 25.6, p=0.316).

Conclusions Our study suggested a protective effect of APOE-ε2 allele against cortical thinning and grey matter volume loss. Future study may examine the effect of APOE-ε2 on brain resilience after brain injury such as stroke.

Authors/Disclosures
Hossam Youssef, MD PRESENTER	Mr. Youssef has nothing to disclose.
Nihas R. Mateti	Mr. Mateti has nothing to disclose.
Erik Middlebrooks	No disclosure on file
Nilufer Taner, MD, PhD, FAAN (Mayo Clinic)	The institution of Dr. Taner has received research support from NIH.
James F. Meschia, MD, FAAN (Mayo Clinic)	The institution of Dr. Meschia has received research support from NINDS. The institution of Dr. Meschia has received research support from NINDS.
Michelle P. Lin, MD (Mayo Clinic Florida)	Dr. Lin has nothing to disclose.