Microglia imaging in methamphetamine use disorder: a positron emission tomography study with the 18 kDa translocator protein radioligand
[F-18]FEPPA.
Addict Biol 2021;
26:e12876. [PMID:
32017280 DOI:
10.1111/adb.12876]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/08/2020] [Accepted: 01/12/2020] [Indexed: 01/19/2023]
Abstract
Activation of brain microglial cells, microgliosis, has been linked to methamphetamine (MA)-seeking behavior, suggesting that microglia could be a new therapeutic target for MA use disorder. Animal data show marked brain microglial activation following acute high-dose MA, but microglial status in human MA users is uncertain, with one positron emission tomography (PET) investigation reporting massively and globally increased translocator protein 18 kDa (TSPO; [C-11](R)-PK11195) binding, a biomarker for microgliosis, in MA users. Our aim was to measure binding of a second-generation TSPO radioligand, [F-18]FEPPA, in brain of human chronic MA users. Regional total volume of distribution (VT ) of [F-18]FEPPA was estimated with a two-tissue compartment model with arterial plasma input function for 10 regions of interest in 11 actively using MA users and 26 controls. A RM-ANOVA corrected for TSPO rs6971 polymorphism was employed to test significance. There was no main effect of group on [F-18]FEPPA VT (P = .81). No significant correlations between [F-18]FEPPA VT and MA use duration, weekly dosage, blood MA concentrations, regional brain volumes, and self-reported craving were observed. Our preliminary findings, consistent with our earlier postmortem data, do not suggest substantial brain microgliosis in MA use disorder but do not rule out microglia as a therapeutic target in MA addiction. Absence of increased [F-18]FEPPA TSPO binding might be related to insufficient MA dose or blunting of microglial response following repeated MA exposure, as suggested by some animal data.
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