title: Bioluminescence and magnetic resonance imaging of macrophage homing to experimental abdominal aortic aneurysms.
abstract: Macrophage infiltration is a prominent feature of abdominal aortic aneurysm (AAA) progression. We used a combined imaging approach with bioluminescence (BLI) and magnetic resonance imaging (MRI) to study macrophage homing and accumulation in experimental AAA disease. Murine AAAs were created via intra-aortic infusion of porcine pancreatic elastase. Mice were imaged over 14 days after injection of prepared peritoneal macrophages. For BLI, macrophages were from transgenic mice expressing luciferase. For MRI, macrophages were labeled with iron oxide particles. Macrophage accumulation during aneurysm progression was observed by in situ BLI and by in vivo 7T MRI. Mice were sacrificed after imaging for histologic analysis. In situ BLI (n  =  32) demonstrated high signal in the AAA by days 7 and 14, which correlated significantly with macrophage number and aortic diameter. In vivo 7T MRI (n  =  13) at day 14 demonstrated T₂* signal loss in the AAA and not in sham mice. Immunohistochemistry and Prussian blue staining confirmed the presence of injected macrophages in the AAA. BLI and MRI provide complementary approaches to track macrophage homing and accumulation in experimental AAAs. Similar dual imaging strategies may aid the study of AAA biology and the evaluation of novel therapies.
authors.affiliation: Divisions of Vascular Surgery and Cardiovascular Medicine and the Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Miyama
authors.forename: Monica M
authors.initials: MM
authors.lastname: Dua
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Schultz
authors.forename: Hisanori
authors.initials: H
authors.lastname: Kosuge
authors.forename: Masahiro
authors.initials: M
authors.lastname: Terashima
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Pisani
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Dalman
authors.forename: Michael V
authors.initials: MV
authors.lastname: McConnell
mesh_terms: D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis* / Q000473:pathology*; D002465:Cell Movement; D005290:Ferric Compounds / Q000378:metabolism; D005295:Ferrocyanides; D037502:Galectin 3 / Q000378:metabolism; D007150:Immunohistochemistry; D008163:Luminescent Measurements / Q000379:methods*; D008264:Macrophages / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013194:Staining and Labeling
chemical_list: D005290:Ferric Compounds; D005295:Ferrocyanides; D037502:Galectin 3; C000499:ferric oxide; C000170:ferric ferrocyanide