title: Preclinical properties of 18F-AV-45: a PET agent for Abeta plaques in the brain.
abstract: beta-amyloid plaques (Abeta plaques) in the brain, containing predominantly fibrillary Abeta peptide aggregates, represent a defining pathologic feature of Alzheimer disease (AD). Imaging agents targeting the Abeta plaques in the living human brain are potentially valuable as biomarkers of pathogenesis processes in AD. (E)-4-(2-(6-(2-(2-(2-(18)F-fluoroethoxy)ethoxy)ethoxy)pyridin-3-yl)vinyl)-N-methyl benzenamine ((18)F-AV-45) is such as an agent currently in phase III clinical studies for PET of Abeta plaques in the brain.
  
  
  METHODS
  In vitro binding of (18)F-AV-45 to Abeta plaques in the postmortem AD brain tissue was evaluated by in vitro binding assay and autoradiography. In vivo biodistribution of (18)F-AV-45 in mice and ex vivo autoradiography of AD transgenic mice (APPswe/PSEN1) with Abeta aggregates in the brain were performed. Small-animal PET of a monkey brain after an intravenous injection of (18)F-AV-45 was evaluated.
  
  
  RESULTS
  (18)F-AV-45 displayed a high binding affinity and specificity to Abeta plaques (K(d), 3.72 +/- 0.30 nM). In vitro autoradiography of postmortem human brain sections showed substantial plaque labeling in AD brains and not in the control brains. Initial high brain uptake and rapid washout from the brain of healthy mice and monkey were observed. Metabolites produced in the blood of healthy mice after an intravenous injection were identified. (18)F-AV-45 displayed excellent binding affinity to Abeta plaques in the AD brain by ex vivo autoradiography in transgenic AD model mice. The results lend support that (18)F-AV-45 may be a useful PET agent for detecting Abeta plaques in the living human brain.
authors.affiliation: Avid Radiopharmaceutical Inc., Philadelphia, Pennsylvania, USA.
authors.forename: Seok Rye
authors.initials: SR
authors.lastname: Choi
authors.forename: Geoff
authors.initials: G
authors.lastname: Golding
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Zhuang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Lim
authors.forename: Franz
authors.initials: F
authors.lastname: Hefti
authors.forename: Tyler E
authors.initials: TE
authors.lastname: Benedum
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kilbourn
authors.forename: Daniel
authors.initials: D
authors.lastname: Skovronsky
authors.forename: Hank F
authors.initials: HF
authors.lastname: Kung
mesh_terms: D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds / Q000378:metabolism* / Q000493:pharmacokinetics; D000818:Animals; D001345:Autoradiography; D001554:Benzene / Q000378:metabolism* / Q000493:pharmacokinetics; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D005026:Ethylene Glycols / Q000378:metabolism* / Q000493:pharmacokinetics; D005260:Female; D000882:Haplorhini; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D049268:Positron-Emission Tomography; D014018:Tissue Distribution
chemical_list: D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D005026:Ethylene Glycols; C545186:florbetapir; D001554:Benzene