Logo image
Multimodal characterization of older APOE2 carriers reveals selective reduction of amyloid load
Journal article   Open access   Peer reviewed

Multimodal characterization of older APOE2 carriers reveals selective reduction of amyloid load

Michel J Grothe, Sylvia Villeneuve, Martin Dyrba, David Bartrés-Faz, Miranka Wirth and Alzheimer's Disease Neuroimaging Initiative
Neurology, Vol.88(6), pp.569-576
02/07/2017
DOI: 10.1212/WNL.0000000000003585
PMCID: PMC5304459
PMID: 28062720
url
https://doi.org/10.1212/WNL.0000000000003585View
Published (Version of record) Open Access

Abstract

To comprehensively assess neurobiological effects of the protective APOE2 allele in the aged brain using a cross-sectional multimodal neuroimaging approach. Multimodal neuroimaging data were obtained from a total of 572 older individuals without dementia (cognitively normal and mild cognitive impairment) enrolled in the Alzheimer's Disease Neuroimaging Initiative and included assessments of regional amyloid load with AV45-PET, glucose metabolism with fluorodeoxyglucose-PET, and gray matter volume with structural MRI. Imaging indexes of APOE2 carriers were contrasted to risk-neutral APOE3 homozygotes, and analyses were controlled for age, sex, education, and clinical diagnosis. Additional models examined genotype-specific effects of age on the imaging markers. In region-of-interest-based analyses, APOE2 carriers had significantly less precuneal amyloid pathology and did not show the typical age-related increase in amyloid load, although the age × genotype interaction was only trend-level significant. In contrast, parietal metabolism and hippocampal volume did not differ between APOE2 and APOE3 genotypes, and both groups showed comparable negative effects of age on these markers. The amyloid specificity of APOE2-related brain changes was corroborated in 2 complementary analyses: spatially unbiased voxel-wise analyses showing widespread reductions in amyloid deposition but no differences in gray matter volume or metabolism and an analysis of CSF-based biomarkers showing a significant effect on amyloid but not on tau pathology. Regarding the range of Alzheimer disease biomarkers considered in the present study, the APOE2 allele appears to have a relatively selective effect on reduced accumulation of amyloid pathology in the aged brain.
Neuroimaging Magnetic Resonance Imaging Brain - diagnostic imaging Humans Male Positron-Emission Tomography Brain - metabolism Multimodal Imaging Aging - genetics Amyloid - metabolism Gray Matter - metabolism Female Cognitive Dysfunction - diagnostic imaging Radiopharmaceuticals Apolipoprotein E2 - genetics Cognitive Dysfunction - metabolism Organ Size Aging - pathology Gray Matter - diagnostic imaging Apolipoprotein E3 - genetics Glucose - metabolism Fluorodeoxyglucose F18 Heterozygote Aged Biomarkers - cerebrospinal fluid Aging - metabolism

Details

Logo image