title: Metabolic imaging with gallium-68- and indium-111-labeled low-density lipoprotein.
abstract: Low-density lipoprotein (LDL) labeled with either gallium-68 (68Ga) or indium-111 (111In) was evaluated as a potential PET or SPECT radiopharmaceutical for determination of hepatic lipoprotein metabolism in rabbits. Gallium-68 or 111In was linked to LDL via diethylenetriaminepentaacetic acid (DTPA) with a 25-70% radiochemical yield. Studies in vivo that compared 68Ga- or 111In-DTPA-LDL with dilactitol-[125I]-tyramine LDL and 131I-LDL showed that both 68Ga- and 111In-labeled LDL behaved as residualizing radiotracers. Localization of radioactivity within the liver of normal rabbits was visualized clearly with [68Ga]DTPA-LDL by PET and with [111In]DTPA-LDL by gamma scintigraphy. Significant differences were observed in hepatic uptake of normal compared with hypercholesterolemic rabbits in which low-capacity LDL receptor-mediated catabolism was saturated. Gallium-68 and 111In-DTPA-LDL are attractive radiopharmaceuticals for noninvasive delineation of tissue LDL metabolism under normal and pathophysiologic conditions.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO 63110.
authors.forename: S M
authors.initials: SM
authors.lastname: Moerlein
authors.forename: A
authors.initials: A
authors.lastname: Daugherty
authors.forename: B E
authors.initials: BE
authors.lastname: Sobel
authors.forename: M J
authors.initials: MJ
authors.lastname: Welch
mesh_terms: D000818:Animals; D005710:Gallium Radioisotopes; D007205:Indium Radioisotopes; D008074:Lipoproteins / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000493:pharmacokinetics*; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism*; D011817:Rabbits; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
chemical_list: D005710:Gallium Radioisotopes; D007205:Indium Radioisotopes; D008074:Lipoproteins; D008077:Lipoproteins, LDL