title: A dual fluorinated and iodinated radiotracer for PET and SPECT imaging of β-amyloid plaques in the brain.
abstract: We report a fluorinated and iodinated radiotracer as a probe for PET/SPECT to detect of β-amyloid (Aβ) plaques in the brain of patients with Alzheimer's disease (AD). We successfully designed and synthesized the fluorinated and iodinated aurone derivative (3) and its radiolabels ([(125)I]3 and [(18)F]3). In binding experiments in vitro, 3 showed high affinity for Aβ aggregates (K(i)=6.81nM). In brain sections of AD model mice, 3 intensely stained Aβ plaques. Furthermore, a specific plaque labeling signal was observed on the autoradiography of postmortem AD brain sections using [(125)I]3. In biodistribution experiments using normal mice, [(125)I]3 and [(18)F]3 displayed good uptake into and a rapid washout from the brain, properties highly desirable for Aβ imaging agents. These results suggest that 3 may function as a PET/SPECT dual imaging agent for detecting Aβ plaques in AD brains.
authors.affiliation: Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ono
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kimura
authors.forename: Shinya
authors.initials: S
authors.lastname: Kagawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nishii
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fuchigami
authors.forename: Mamoru
authors.initials: M
authors.lastname: Haratake
authors.forename: Morio
authors.initials: M
authors.lastname: Nakayama
authors.forename: Hideo
authors.initials: H
authors.lastname: Saji
mesh_terms: D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D001345:Autoradiography; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods*; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D016229:Amyloid beta-Peptides; D005462:Fluorine Radioisotopes; D007457:Iodine Radioisotopes