Early cerebral amyloid-β accumulation and hypermetabolism are associated with subtle cognitive deficits before accelerated cerebral atrophy

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Abstract

Aims
Alzheimer’s disease (AD) is characterized by the accumulation of amyloid beta (Aβ) in the brain. The deposition of Aβ is believed to initiate a detrimental cascade, including cerebral hypometabolism, accelerated brain atrophy, and cognitive problems—ultimately resulting in AD. However, the timing and causality of the cascade resulting in AD are not yet fully established. Therefore, we examined whether early Aβ accumulation affects cerebral glucose metabolism, atrophy rate, and age-related cognitive decline before the onset of neurodegenerative disease.

Methods
Participants from the Metropolit 1953 Danish Male Birth Cohort underwent brain positron emission tomography (PET) imaging using the radiotracers [11C]Pittsburgh Compound-B (PiB) (N = 70) and [18F]Fluorodeoxyglucose (FDG) (N = 76) to assess cerebral Aβ accumulation and glucose metabolism, respectively. The atrophy rate was calculated from anatomical magnetic resonance imaging (MRI) scans conducted presently and 10 years ago. Cognitive decline was examined from neurophysiological tests conducted presently and ten or 5 years ago.

Results
Higher Aβ accumulation in AD-critical brain regions correlated with greater visual memory decline (p = 0.023). Aβ accumulation did not correlate with brain atrophy rates. Increased cerebral glucose metabolism in AD-susceptible regions correlated with worse verbal memory performance (p = 0.040).

Conclusions
Aβ accumulation in known AD-related areas was associated with subtle cognitive deficits. The association was observed before hypometabolism or accelerated brain atrophy, suggesting that Aβ accumulation is involved early in age-related cognitive dysfunction. The association between hypermetabolism and worse memory performance may be due to early compensatory mechanisms adapting for malfunctioning neurons by increasing metabolism.
OriginalsprogEngelsk
TidsskriftGeroScience
Vol/bind46
Sider (fra-til)769–782
Antal sider14
ISSN2509-2715
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
Open access funding provided by Copenhagen University The study was supported by the Lundbeck Foundation, the Independent Research Fund Denmark, and the Novo Nordisk Foundation, and by a Nordea Foundation Grant to the Center for Healthy Ageing at the University of Copenhagen. The Copenhagen Ageing and Midlife Biobank are supported by grants from the Velux Foundation (VELUX26145 and 31539). MBV was funded by a grant from the Lundbeck Foundation (R347-2020–217).

Publisher Copyright:
© 2023, The Author(s).

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