title: Imaging rhodopsin degeneration in vivo in a new model of ocular ischemia in living mice.
abstract: Delivery of antibodies to monitor key biomarkers of retinopathy in vivo represents a significant challenge because living cells do not take up immunoglobulins to cellular antigens. We met this challenge by developing novel contrast agents for retinopathy, which we used with magnetic resonance imaging (MRI). Biotinylated rabbit polyclonal to chick IgY (rIgPxcIgY) and phosphorylthioate-modified oligoDNA (sODN) with random sequence (bio-sODN-Ran) were conjugated with NeutrAvidin-activated superparamagnetic iron oxide nanoparticles (SPION). The resulting Ran-SPION-rIgPxcIgY carries chick polyclonal to microtubule-associated protein 2 (MAP2) as Ran-SPION-rIgP/cIgY-MAP2, or to rhodopsin (Rho) as anti-Rho-SPION-Ran. We examined the uptake of Ran-SPION-rIgP/cIgY-MAP2 or SPION-rIgP/cIgY-MAP2 in normal C57black6 mice (n = 3 each, 40 μg/kg, i.c.v.); we found retention of Ran-SPION-rIgP/cIgY-MAP2 using molecular contrast-enhanced MRI in vivo and validated neuronal uptake using Cy5-goat IgPxcIgY ex vivo. Applying this novel method to monitor retinopathy in a bilateral carotid artery occlusion-induced ocular ischemia, we observed pericytes (at d 2, using Gd-nestin, by eyedrop solution), significant photoreceptor degeneration (at d 20, using anti-Rho-SPION-Ran, eyedrops, P = 0.03, Student's t test), and gliosis in Müller cells (at 6 mo, using SPION-glial fibrillary acidic protein administered by intraperitoneal injection) in surviving mice (n ≥ 5). Molecular contrast-enhanced MRI results were confirmed by optical and electron microscopy. We conclude that chimera and molecular contrast-enhanced MRI provide sufficient sensitivity for monitoring retinopathy and for theranostic applications.
authors.affiliation: *Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA, and Schepens Eye Research Institute/Massachusetts Eye and Ear Infirmary, Harvard Medical School, Cambridge, Massachusetts, USA.
authors.forename: Jiaqian
authors.initials: J
authors.lastname: Ren
authors.affiliation: *Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA, and Schepens Eye Research Institute/Massachusetts Eye and Ear Infirmary, Harvard Medical School, Cambridge, Massachusetts, USA.
authors.forename: Yinching I
authors.initials: YI
authors.lastname: Chen
authors.affiliation: *Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA, and Schepens Eye Research Institute/Massachusetts Eye and Ear Infirmary, Harvard Medical School, Cambridge, Massachusetts, USA.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Mackey
authors.affiliation: *Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA, and Schepens Eye Research Institute/Massachusetts Eye and Ear Infirmary, Harvard Medical School, Cambridge, Massachusetts, USA philipl@mgh.harvard.edu.
authors.forename: Philip K
authors.initials: PK
authors.lastname: Liu
mesh_terms: D000818:Animals; D002545:Brain Ischemia; D002339:Carotid Arteries; D003287:Contrast Media; D005131:Eye Injuries / Q000378:metabolism*; D007511:Ischemia / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D012164:Retinal Diseases / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*
chemical_list: D003287:Contrast Media; D012243:Rhodopsin
keywords: chimeric MR CA; nanotechnology; retinopathy; target-guided delivery strategies