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[ 18 F] GE 180 positron emission tomographic imaging indicates a potential double‐hit insult in the intrahippocampal kainate mouse model of temporal lobe epilepsy
Author(s) -
Brackhan Mirjam,
Bascuñana Pablo,
Ross Tobias L.,
Bengel Frank M.,
Bankstahl Jens P.,
Bankstahl Marion
Publication year - 2018
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.14009
Subject(s) - epileptogenesis , status epilepticus , translocator protein , epilepsy , kainate receptor , hippocampus , temporal lobe , microdialysis , positron emission tomography , nuclear medicine , medicine , statistical parametric mapping , pathology , neuroscience , inflammation , psychology , magnetic resonance imaging , central nervous system , radiology , glutamate receptor , neuroinflammation , ampa receptor , receptor
Summary Objective Accumulating evidence suggests that brain inflammation, elicited by epileptogenic insults, is involved in epilepsy development. Noninvasive nuclear imaging of brain inflammation in animal models of epileptogenesis represents a diagnostic in vivo approach with potential for direct translation into the clinic. Here, we investigated up‐regulation of the translocator protein ( TSPO ) indicative of microglial activation by serial [ 18 F] GE 180 positron emission tomographic ( PET ) imaging in a mouse model of temporal lobe epilepsy. Methods As epileptogenic insult, a status epilepticus ( SE ) was induced in mice by intrahippocampal injection of kainate. Post‐ SE mice injected with kainate and sham‐injected mice were subjected to [ 18 F] GE 180 PET scans before SE and at 2 days, 5‐7 days, 2 weeks, 3 weeks, 7 weeks, and 14 weeks postinsult. For data evaluation, brain regions ipsilateral and contralateral to the injection site were outlined by coregistration with a standard mouse brain atlas, and percentage of injected dose per cubic centimeter was calculated. In addition, a statistical parametric mapping analysis, comparing post‐ SE mice to baseline, sham mice to baseline, and post‐ SE to sham mice was performed. Results Following SE , elevations in [ 18 F] GE 180 uptake were most prominent in the ipsilateral hippocampus, occurring between 2 days and at least 7 weeks after SE , with a peak at 5‐7 days after SE . In the contralateral hippocampus and other epilepsy‐associated brain regions, increased tracer uptake was observed with a similar time profile but to a lesser extent. Moderate enhancement of tracer uptake was also evident in mice after sham surgery. Significance TSPO in vivo imaging reliably detects brain inflammation during epileptogenesis. These inflammatory processes most prominently affect the hippocampus ipsilateral to the injection site. Inflammation induced by the traumatic insult associated with surgery synergistically contributes to total brain inflammation and may also contribute to epileptogenesis. The revealed time course of neuroinflammation will help to identify appropriate time points for anti‐inflammatory, potentially antiepileptogenic treatment.