title: Increased in vivo expression of an inflammatory marker in temporal lobe epilepsy.
abstract: Animal studies and clinical observations suggest that epilepsy is associated with inflammation. Translocator protein (TSPO) (18 kDa), a marker of inflammation, is increased in vitro in surgical samples from patients with temporal lobe epilepsy. TSPO can be measured in the living human brain with PET and the novel radioligand (11)C-PBR28. In this study, we sought to determine whether in vivo expression of TSPO is increased ipsilateral to the seizure focus in patients with temporal lobe epilepsy.
  
  
  METHODS
  Sixteen patients with unilateral temporal lobe epilepsy and 30 healthy subjects were studied with (11)C-PBR28 PET and MRI. Uptake of radioactivity after injection of (11)C-PBR28 was measured from regions of interest drawn bilaterally onto MR images. Brain uptake from ipsilateral and contralateral hemispheres was compared using a paired-samples t test.
  
  
  RESULTS
  We found that brain uptake was higher ipsilateral to the seizure focus in the hippocampus, parahippocampal gyrus, amygdala, fusiform gyrus, and choroid plexus but not in other brain regions. This asymmetry was more pronounced in patients with hippocampal sclerosis than in those without.
  
  
  CONCLUSIONS
  We found increased uptake of radioactivity after injection of (11)C-PBR28 ipsilateral to the seizure focus in patients with temporal lobe epilepsy, suggesting increased expression of TSPO. Studies in larger samples are required to confirm this finding and determine the clinical utility of imaging TSPO in temporal lobe epilepsy.
authors.affiliation: Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1026, USA.
authors.forename: Jussi
authors.initials: J
authors.lastname: Hirvonen
authors.forename: William C
authors.initials: WC
authors.lastname: Kreisl
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujita
authors.forename: Irene
authors.initials: I
authors.lastname: Dustin
authors.forename: Omar
authors.initials: O
authors.lastname: Khan
authors.forename: Shmuel
authors.initials: S
authors.lastname: Appel
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Cheryl
authors.initials: C
authors.lastname: Morse
authors.forename: Victor W
authors.initials: VW
authors.lastname: Pike
authors.forename: Robert B
authors.initials: RB
authors.lastname: Innis
authors.forename: William H
authors.initials: WH
authors.lastname: Theodore
mesh_terms: D000328:Adult; D001692:Biological Transport; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D054022:Cerebrum / Q000000981:diagnostic imaging / Q000378:metabolism; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011743:Pyrimidines / Q000378:metabolism; D018079:Receptors, GABA / Q000378:metabolism*; D055815:Young Adult
chemical_list: C526315:(methyl-(11)C)N-acetyl-N-(2-methoxybenzyl)-2-phenoxy-5-pyridinamine; D015415:Biomarkers; D011743:Pyrimidines; D018079:Receptors, GABA; C499229:TSPO protein, human