Influence of TSPO genotype on 11C-PBR28 standardized uptake values

• Published in: The Journal of nuclear medicine (1978) Vol. 54; no. 8; pp. 1320 - 1322
• Main Authors: Yoder, Karmen K, Nho, Kwangsik, Risacher, Shannon L, Kim, Sungeun, Shen, Li, Saykin, Andrew J
• Format: Journal Article
• Language: English
• Published: United States 01.08.2013
• Subjects: Aged; Biological Transport - genetics; Brain - diagnostic imaging; Brain - metabolism; Female; Genotype; Humans; Male; Polymorphism, Single Nucleotide; Positron-Emission Tomography; Pyrimidines - metabolism; Receptors, GABA - genetics; Reference Standards; 11C-PBR28; TSPO; positron emission tomography; genotype
• ISSN: 1535-5667; 0161-5505; 1535-5667
• DOI: 10.2967/jnumed.112.118885

(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. 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. SUV was 30% lower in T/C subjects than in C/C subjects. The results indicate that brain (11)C-PBR28 SUV is sensitive to TSPO genotype.