In Pre-Clinical AD Small Vessel Disease is Associated With Altered Hippocampal Connectivity and Atrophy.
Am J Geriatr Psychiatry
; 31(2): 112-123, 2023 02.
Article
in En
| MEDLINE
| ID: mdl-36274019
ABSTRACT
OBJECTIVE:
Small Vessel Disease (SVD) is known to be associated with higher AD risk, but its relationship to amyloidosis in the progression of AD is unclear. In this cross-sectional study of cognitively normal older adults, we explored the interactive effects of SVD and amyloid-beta (Aß) pathology on hippocampal functional connectivity during an associative encoding task and on hippocampal volume.METHODS:
This study included 61 cognitively normal older adults (age range 65-93 years, age mean ± standard deviation 75.8 ± 6.4, 41 [67.2%] female). PiB PET, T2-weighted FLAIR, T1-weighted and face-name fMRI images were acquired on each participant to evaluate brain Aß, white matter hyperintensities (WMH+/- status), gray matter density, and hippocampal functional connectivity.RESULTS:
We found that, in WMH (+) older adults greater Aß burden was associated with greater hippocampal local connectivity (i.e., hippocampal-parahippocampal connectivity) and lower gray matter density in medial temporal lobe (MTL), whereas in WMH (-) older adults greater Aß burden was associated with greater hippocampal distal connectivity (i.e., hippocampal-prefrontal connectivity) and no changes in MTL gray matter density. Moreover, greater hippocampal local connectivity was associated with MTL atrophy.CONCLUSION:
These observations support a hippocampal excitotoxicity model linking SVD to neurodegeneration in preclinical AD. This may explain how SVD may accelerate the progression from Aß positivity to neurodegeneration, and subsequent AD.Key words
Full text:
1
Database:
MEDLINE
Main subject:
Alzheimer Disease
/
Hippocampus
Type of study:
Observational_studies
/
Risk_factors_studies
Limits:
Aged
/
Aged80
/
Female
/
Humans
/
Male
Language:
En
Journal:
Am J Geriatr Psychiatry
Journal subject:
GERIATRIA
/
PSIQUIATRIA
Year:
2023
Type:
Article