Distribution Pattern of the Monoamine Oxidase B Ligand, 18F-THK5351, in the Healthy Brain.

Abstract

BACKGROUND:

18F-THK5351 PET estimates the concentrations of monoamine oxidase B (MAO-B) that are preferentially located in astrocytes and can be used to visualize and quantify ongoing astrogliosis. To study images of astrogliosis in neurological disorders, it is essential to understand the detailed binding sites of 18F-THK5351 as the MAO-B ligand under normal conditions. In this study, we examined the detailed distribution pattern of 18F-THK5351 in the healthy brain by comparing 18F-THK5351 uptake between subjects taking and not taking the MAO-B inhibitor.

METHODS:

Ten healthy controls (HCs: 67.4 [SD, 15.1] years) and 4 patients with Parkinson disease taking the MAO-B inhibitor underwent 18F-THK5351 PET. The uptake ratio index (URI) was defined to quantify 18F-THK5351 uptake, using the cerebellum as a reference region. The cerebellar URI was set to zero.

RESULTS:

For HCs, regions with URI ≥1 were preferentially observed in the following order: the striatum, globus pallidus, thalamus, hypothalamus, amygdala, periaqueductal gray, substantia nigra, medulla, hippocampus, and pons. The peak URI values in the corresponding regions were 2.93, 2.47, 2.12, 2.04, 1.84, 1.68, 1.67, 1.37, 1.20, and 1.11, respectively. For all patients with Parkinson disease taking the MAO-B inhibitor, the URI values in all these regions were significantly decreased (Z score >2) and were reduced from 60.4% to 99.9%, compared with HCs.

CONCLUSIONS:

This study presented the detailed distribution pattern of 18F-THK5351 in HCs and suggests that 18F-THK5351 uptake largely reflects MAO-B concentrations under normal conditions.

• Authors: Kenji Ishibashi, Yoshiharu Miura, Tetsuro Tago, Jun Toyohara, Mana Higashihara, Atsushi Iwata, Kenji Ishii
• Journal: Clinical nuclear medicine (Clin Nucl Med) Vol. 47 Issue 7 Pg. e489-e495 (Jul 01 2022) ISSN: 1536-0229 [Electronic] United States
• PMID: 35675140 (Publication Type: Journal Article)
• Copyright: Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.

Chemical References

• Aminopyridines
• Ligands
• Monoamine Oxidase Inhibitors
• Quinolines
• THK5351

Topics

• Aminopyridines (pharmacokinetics)
• Brain (diagnostic imaging, metabolism)
• Gliosis (metabolism)
• Humans
• Ligands
• Monoamine Oxidase Inhibitors (therapeutic use)
• Parkinson Disease (diagnostic imaging, metabolism)
• Positron-Emission Tomography
• Quinolines (pharmacokinetics)