Detection of amyloid plaques targeted by USPIO-Aβ1-42 in Alzheimer's disease transgenic mice using magnetic resonance microimaging.

Abstract

Amyloid plaques are one of the pathological hallmarks of Alzheimer's disease (AD). The visualization of amyloid plaques in the brain is important to monitor AD progression and to evaluate the efficacy of therapeutic interventions. Our group has developed several contrast agents to detect amyloid plaques in vivo using magnetic resonance microimaging (μMRI) in AD transgenic mice, where we used intra-carotid mannitol to enhance blood-brain barrier (BBB) permeability. In the present study, we used ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, chemically coupled with Aβ1-42 peptide to detect amyloid deposition along with mannitol for in vivo μMRI by femoral intravenous injection. A 3D gradient multi-echo sequence was used for imaging with a 100μm isotropic resolution. The amyloid plaques detected by T2*-weighted μMRI were confirmed with matched histological sections. Furthermore, two different quantitative analyses were used. The region of interest-based quantitative measurement of T2* values showed contrast-injected APP/PS1 mice had significantly reduced T2* values compared to wild-type mice. In addition, the scans were examined with voxel-based morphometry (VBM) using statistical parametric mapping (SPM) for comparison of contrast-injected AD transgenic and wild-type mice. The regional differences seen in VBM comparing USPIO-Aβ1-42 injected APP/PS1 and wild-type mice correlated with the amyloid plaque distribution histologically, contrasting with no differences between the two groups of mice without contrast agent injection in regions of the brain with amyloid deposition. Our results demonstrated that both approaches were able to identify the differences between AD transgenic mice and wild-type mice, after injected with USPIO-Aβ1-42. The feasibility of using less invasive intravenous femoral injections for amyloid plaque detection in AD transgenic mice facilitates using this method for longitudinal studies in the pathogenesis of AD.

• Authors: Jing Yang, Youssef Zaim Wadghiri, Dung Minh Hoang, Wai Tsui, Yanjie Sun, Erika Chung, Yongsheng Li, Andrew Wang, Mony de Leon, Thomas Wisniewski
• Journal: NeuroImage (Neuroimage) Vol. 55 Issue 4 Pg. 1600-9 (Apr 15 2011) ISSN: 1095-9572 [Electronic] United States
• PMID: 21255656 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• Amyloid beta-Peptides
• Contrast Media
• Dextrans
• Magnetite Nanoparticles
• Peptide Fragments
• amyloid beta-protein (1-42)
• ferumoxtran-10

Topics

• Alzheimer Disease (complications, diagnosis)
• Amyloid beta-Peptides
• Animals
• Contrast Media
• Dextrans
• Drug Delivery Systems (methods)
• Magnetic Resonance Imaging (methods)
• Magnetite Nanoparticles
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Peptide Fragments
• Plaque, Amyloid (complications, diagnosis)
• Reproducibility of Results
• Sensitivity and Specificity