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. 2017 Feb 1;174(2):118-124.
doi: 10.1176/appi.ajp.2016.16020171. Epub 2016 Sep 9.

Imaging Microglial Activation in Untreated First-Episode Psychosis: A PET Study With [18F]FEPPA

Sina Hafizi  1 , Huai-Hsuan Tseng  1 , Naren Rao  1 , Thiviya Selvanathan  1 , Miran Kenk  1 , Richard P Bazinet  1 , Ivonne Suridjan  1 , Alan A Wilson  1 , Jeffrey H Meyer  1 , Gary Remington  1 , Sylvain Houle  1 , Pablo M Rusjan  1 , Romina Mizrahi  1
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Imaging Microglial Activation in Untreated First-Episode Psychosis: A PET Study With [18F]FEPPA

Sina Hafizi et al. Am J Psychiatry. .

Abstract

Objective: Neuroinflammation and abnormal immune responses are increasingly implicated in the pathophysiology of schizophrenia. Previous positron emission tomography (PET) studies targeting the translocator protein 18 kDa (TSPO) have been limited by high nonspecific binding of the first-generation radioligand, low-resolution scanners, small sample sizes, and psychotic patients being on antipsychotics or not being in the first episode of their illness. The present study uses the novel second-generation TSPO PET radioligand [18F]FEPPA to evaluate whether microglial activation is elevated in the dorsolateral prefrontal cortex and hippocampus of untreated patients with first-episode psychosis.

Method: Nineteen untreated patients with first-episode psychosis (14 of them antipsychotic naive) and 20 healthy volunteers underwent a high-resolution [18F]FEPPA PET scan and MRI. Dynamic PET data were analyzed using the validated two-tissue compartment model with arterial plasma input function with total volume of distribution (VT) as outcome measure. All analyses were corrected for TSPO rs6971 polymorphism (which is implicated in differential binding affinity).

Results: No significant differences were observed between patients and healthy volunteers in microglial activation, as indexed by [18F]FEPPA VT, in either the dorsolateral prefrontal cortex or the hippocampus. There were no significant correlations between [18F]FEPPA VT and duration of illness, clinical presentation, or neuropsychological measures after adjusting for multiple testing.

Conclusions: The lack of significant differences in [18F]FEPPA VT between groups suggests that microglial activation is not present in first-episode psychosis.

Keywords: Imaging; Microglia; Neuroinflammation; PET; Psychosis; Schizophrenia.

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Figures

FIGURE 1
FIGURE 1. Total Distribution Volume (VT) of [18F]FEPPA in Patients With First-Episode Psychosis and Healthy Volunteers Across Different Regions of Interesta
aHorizontal black lines represent mean values.
FIGURE 2
FIGURE 2. Relationship Between [18F]FEPPA VT in Hippocampus and RBANS Total Score in First-Episode Psychosis
See this image and copyright information in PMC

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References

    1. Kreutzberg GW. Microglia: a sensor for pathological events in the CNS. Trends Neurosci. 1996;19:312–318. - PubMed
    1. Gehrmann J, Matsumoto Y, Kreutzberg GW. Microglia: intrinsic immuneffector cell of the brain. Brain Res Brain Res Rev. 1995;20:269–287. - PubMed
    1. Carbonell WS, Murase S, Horwitz AF, et al. Migration of perilesional microglia after focal brain injury and modulation by CC chemokine receptor 5: an in situ time-lapse confocal imaging study. J Neurosci. 2005;25:7040–7047. - PMC - PubMed
    1. Burguillos MA, Deierborg T, Kavanagh E, et al. Caspase signalling controls microglia activation and neurotoxicity. Nature. 2011;472:319–324. - PubMed
    1. Venneti S, Wiley CA, Kofler J. Imaging microglial activation during neuroinflammation and Alzheimer’s disease. J Neuroimmune Pharmacol. 2009;4:227–243. - PMC - PubMed

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