Near-infrared fluorescence imaging of murine atherosclerosis using an oxidized low density lipoprotein-targeted fluorochrome

Int J Cardiovasc Imaging. 2014 Jan;30(1):221-31. doi: 10.1007/s10554-013-0320-9. Epub 2013 Oct 30.

Abstract

The aim of this study was to explore the feasibility of detecting plaques using an NIR797 fluorochrome-labeled, anti-oxLDL antibody (anti-oxLDL-NIR797) and near-infrared fluorescence (NIRF) imaging in a murine model of atherosclerosis. Anti-mouse oxLDL polyclonal antibodies were conjugated to NIR797 dyes to synthesis oxLDL-targeted NIRF probe. In situ and ex vivo NIRF imaging of the high-cholesterol diet-induced atherosclerotic lesions of apoE-/- mice (baseline) as well as ex vivo NIRF imaging in the progression and regression group (without or with atorvastatin treatment for another 8 weeks) were performed 24 h after an intravenous injection of 1 mg/kg of anti-oxLDL-NIR797, while phosphate-buffered saline (PBS) was used for the controls. The plaque areas were investigated using Oil Red O (ORO) staining. Aortas isolated from the apoE-/- mice 24 h post-injection exhibited a selective, strong, heterogeneous NIRF signal enhancement in the aortic root, arch, and bifurcation, whereas the PBS and competitive inhibition groups had limited NIRF signal changes (p < 0.05). There was a significant correlation between ORO staining and NIRF in the atherosclerotic aortas that received anti-oxLDL-NIR797. Immunofluorescence studies confirmed the colocalization of the oxLDL/macrophages and NIR797 fluorochromes. Furthermore, the atherosclerotic lesions of atorvastatin-treated mice showed reduced anti-oxLDL-NIR797 uptake and oxLDL expression. These results indicate that NIRF plaque imaging is feasible with an oxLDL-targeted NIRF probe. Thus, oxLDL-based molecular imaging of atherosclerotic plaques is feasible and may provide important methods for characterizing vulnerable plaques and monitoring the response to therapeutic interventions for atherosclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / metabolism*
  • Aorta / drug effects
  • Aorta / metabolism*
  • Aorta / pathology
  • Aortic Diseases / drug therapy
  • Aortic Diseases / genetics
  • Aortic Diseases / metabolism*
  • Aortic Diseases / pathology
  • Apolipoproteins E / deficiency
  • Apolipoproteins E / genetics
  • Atherosclerosis / drug therapy
  • Atherosclerosis / genetics
  • Atherosclerosis / metabolism*
  • Atherosclerosis / pathology
  • Atorvastatin
  • Cell Line
  • Cholesterol, Dietary
  • Disease Models, Animal
  • Disease Progression
  • Feasibility Studies
  • Fluorescent Dyes / metabolism*
  • Heptanoic Acids / pharmacology
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Isothiocyanates / metabolism*
  • Lipoproteins, LDL / immunology
  • Lipoproteins, LDL / metabolism*
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Optical Imaging*
  • Plaque, Atherosclerotic
  • Pyrroles / pharmacology
  • Time Factors

Substances

  • Antibodies
  • Apolipoproteins E
  • Cholesterol, Dietary
  • Fluorescent Dyes
  • Heptanoic Acids
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Isothiocyanates
  • Lipoproteins, LDL
  • Pyrroles
  • oxidized low density lipoprotein
  • Atorvastatin