Browse by author
Lookup NU author(s): Professor David BrooksORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
Background: The average human lifespan has increased dramatically over the past century. However, molecular and physiological alterations of the healthy brain during aging remain incompletely understood. Generalized synaptic restructuring may be an important contributor to healthy aging and could contribute to the observed reduced metabolism in the aged brain, but in vivo evidence is lacking. Objective: The objective of this study was to assess healthy brain aging using [18F]FDG as a measure of cerebral glucose consumption and [11 C]UCB-J PET as an indicator of synaptic density. Method: Using in vivo PET imaging and the novel synaptic-vesicle-glycoprotein 2A (SV2A) radioligand [11C]UCB-J alongside with the fluorodeoxyglucose radioligand [18F]FDG, we obtained SUVR-1 values for 14 pre-defined volume-of-interest brain regions defined on MRI T1 scans. Regional differences in relative [18F]FDG and [11C]UCB-J uptake were investigated using a voxel-wise approach. Finally, correlations between [11C]UCB-J, [18F]FDG PET, and age were examined. Results: Using in vivo [11C]UCB-J PET we found widespread cortical reduction of synaptic density in a cohort of older HC subjects (N=15) compared with young HC subjects (N=11). However, no reduction persisted after partial volume correction and corrections for multiple comparison. Our study confirms previously reported synaptic stability during aging. Regional differences in relative [18F]FDG and [11C]UCB-J uptake were observed with up to 20% higher [11C]UCB-J uptake in the amygdala and temporal lobe and up to 34% higher glucose metabolism in thalamus, striatum, occipital, parietal and frontal cortex. Significant correlation was seen between age and [18F]FDG SUVR-1 in all 14 selected brain regions. Discussion and Conclusion: In vivo PET using [11C]UCB-J does not support a cortical decrease of synaptic density during aging. Thus, loss of synaptic density may be unrelated to aging and does not seem to be a sufficient explanation for the recognized reduction in brain metabolism during aging. Our study also demonstrates that the relationship between glucose consumption and synaptic density is not uniform throughout the human brain with implications for our understanding of neuroenergetics.
Author(s): Andersen KB, Hansen AK, Knudsen K, Schacht AC, Damholdt MF, Brooks DJ, Borghammer P
Publication type: Article
Publication status: Published
Journal: Nuclear Medicine and Biology
Year: 2022
Volume: 112-113
Pages: 52-58
Print publication date: 01/09/2022
Online publication date: 08/07/2022
Acceptance date: 28/06/2022
Date deposited: 11/07/2022
ISSN (print): 0969-8051
ISSN (electronic): 1872-9614
Publisher: Elsevier
URL: https://doi.org/10.1016/j.nucmedbio.2022.06.007
DOI: 10.1016/j.nucmedbio.2022.06.007
ePrints DOI: 10.57711/hwrc-d225
Altmetrics provided by Altmetric
