title: Evaluation of atherosclerotic lesions using dextran- and mannan-dextran-coated USPIO: MRI analysis and pathological findings.
abstract: Magnetic resonance imaging (MRI) can detect atherosclerotic lesions containing accumulations of ultrasmall superparamagnetic iron oxides (USPIO). Positing that improved USPIO with a higher affinity for atherosclerotic plaques would yield better plaque images, we performed MRI and histologic studies to compare the uptake of dextran- and mannan-dextran-coated USPIO (D-USPIO and DM-USPIO, respectively) by the atherosclerotic walls of rabbits. We intravenously injected atherosclerotic rabbits with DM-USPIO (n = 5) or D-USPIO (n = 5). Two rabbits were the controls. The doses delivered were 0.08 (dose 1) (n = 1), 0.4 (dose 2) (n = 1), or 0.8 (dose 3) (n = 3) mmol iron/Kg. The dose 3 rabbits underwent in vivo contrast-enhanced magnetic resonance angiography (MRA) before and 5 days after USPIO administration. Afterwards, all animals were euthanized, the aortae were removed and subjected to in vitro MRI study. The signal-to-noise ratio (SNR) of the aortic wall in the same region of interest (ROI) was calculated in both in vivo and in vitro studies. Histological assessment through measurement of iron-positive regions in Prussian blue-stained specimens showed that iron-positive regions were significantly larger in rabbits injected with DM- rather than D-USPIO (P < 0.05) for all doses. In vivo MRA showed that the SNR-reducing effect of DM- was greater than that of D-USPIO (P < 0.05). With in vitro MRI scans, SNR was significantly lower in rabbits treated with dose 2 of DM-USPIO compared with D-USPIO treatment (P < 0.05), and it tended to be lower at dose 3 (P < 0.1). In conclusion, we suggest that DM-USPIO is superior to D-USPIO for the study of atherosclerotic lesions in rabbits.
authors.affiliation: Department of Radiology, Shiga University of Medical Science, Otsu, Shiga, Japan. keikot@belle.shiga-medac.jp
authors.forename: Keiko
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Norihisa
authors.initials: N
authors.lastname: Nitta
authors.forename: Akinaga
authors.initials: A
authors.lastname: Sonoda
authors.forename: Ayumi
authors.initials: A
authors.lastname: Nitta-Seko
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ohta
authors.forename: Masashi
authors.initials: M
authors.lastname: Takahashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Murata
authors.forename: Kenichi
authors.initials: K
authors.lastname: Mukaisho
authors.forename: Masashi
authors.initials: M
authors.lastname: Shiomi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tabata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nohara
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000175:diagnosis* / Q000473:pathology; D002460:Cell Line; D020099:Coated Materials, Biocompatible; D003911:Dextrans; D006938:Hyperlipoproteinemia Type II / Q000473:pathology; D008264:Macrophages / Q000502:physiology; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000706:statistics & numerical data; D058185:Magnetite Nanoparticles; D008351:Mannans; D051379:Mice; D050997:Nanomedicine; D010587:Phagocytosis; D011817:Rabbits; D059629:Signal-To-Noise Ratio
chemical_list: D020099:Coated Materials, Biocompatible; D003911:Dextrans; D058185:Magnetite Nanoparticles; D008351:Mannans