Publication Type Academic Article
Authors Kang Y, Rúa S, Kaunzner U, Perumal J, Nealon N, Qu W, Kothari P, Vartanian T, Kuceyeski A, Gauthier S
Journal Mol Imaging Biol
Volume 22
Issue 6
Pagination 1600-1608
Date Published 12/01/2020
ISSN 1860-2002
Keywords Inflammation, Multiple Sclerosis, Positron-Emission Tomography, Receptors, GABA
Abstract PURPOSE: The γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter and essential for normal brain function. The GABAergic system has been shown to have immunomodulatory effects and respond adaptively to excitatory toxicity. The association of the GABAergic system and inflammation in patients with multiple sclerosis (MS) remains unknown. In this pilot study, the in vivo relationship between GABAA binding and the innate immune response is explored using positron emission tomography (PET) with [11C] flumazenil (FMZ) and [11C]-PK11195 PET (PK-PET), a measure of activated microglia/macrophages. PROCEDURES: Sixteen MS patients had dynamic FMZ-PET and PK-PET imaging. Ten age-matched healthy controls (HC) had a single FMZ-PET. GABAA receptor binding was calculated using Logan reference model with the pons as reference. Distribution of volume ratio (VTr) for PK-PET was calculated using image-derived input function. A hierarchical linear model was fitted to assess the linear association between PK-PET and FMZ-PET among six cortical regions of interest. RESULTS: GABAA receptor binding was higher throughout the cortex in MS patients (5.72 ± 0.91) as compared with HC (4.70 ± 0.41) (p = 0.002). A significant correlation was found between FMZ binding and PK-PET within the cortex (r = 0.61, p < 0.001) and among the occipital (r = 0.61, p = 0.012), parietal (r = 0.49, p = 0.041), and cingulate (r = 0.32, p = 0.006) regions. CONCLUSIONS: A higher GABAA receptor density in MS subjects compared with HC was observed and correlated with innate immune activity. Our observations demonstrate that immune-driven GABAergic abnormalities may be present in MS.
DOI 10.1007/s11307-020-01501-z
PubMed ID 32394283
PubMed Central ID PMC8769531
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