title: Influence of TSPO genotype on 11C-PBR28 standardized uptake values.
abstract: (11)C-PBR28 binds to the high-affinity state of the translocator protein 18 kDa (TSPO). A single-nucleotide polymorphism (rs6971) within the human TSPO gene determines the affinity state of the TSPO. The rs6971 genotype determines whether individuals express the high-, low-, or mixed-affinity phenotype of TSPO. The rs6971 genotype corresponds to in vivo (11)C-PBR28 binding, as measured quantitatively by total volume of distribution. However, it is not known whether standardized uptake value (SUV) can detect differences in brain (11)C-PBR28 uptake by TSPO genotype.
  
  
  METHODS
  Thirty-two older adults (71.8 ± 7.94 y old) underwent (11)C-PBR28 PET scanning; rs6971 genotype was imputed after genomewide genotyping. SUV was extracted for several brain regions. The sample included 19 C/C carriers (high-affinity phenotype), 12 T/C carriers (mixed-affinity), and 1 T/T carrier (low-affinity) for rs6971.
  
  
  RESULTS
  SUV was 30% lower in T/C subjects than in C/C subjects.
  
  
  CONCLUSIONS
  The results indicate that brain (11)C-PBR28 SUV is sensitive to TSPO genotype.
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. kkyoder@iupui.edu
authors.forename: Karmen K
authors.initials: KK
authors.lastname: Yoder
authors.forename: Kwangsik
authors.initials: K
authors.lastname: Nho
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Risacher
authors.forename: Sungeun
authors.initials: S
authors.lastname: Kim
authors.forename: Li
authors.initials: L
authors.lastname: Shen
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Saykin
mesh_terms: D000368:Aged; D001692:Biological Transport / Q000235:genetics; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D049268:Positron-Emission Tomography; D011743:Pyrimidines / Q000378:metabolism*; D018079:Receptors, GABA / Q000235:genetics*; D012015:Reference Standards
chemical_list: C526315:(methyl-(11)C)N-acetyl-N-(2-methoxybenzyl)-2-phenoxy-5-pyridinamine; D011743:Pyrimidines; D018079:Receptors, GABA; C499229:TSPO protein, human
keywords: 11C-PBR28; TSPO; genotype; positron emission tomography