Magnetic Resonance Imaging of Brain Inflammation Using Microparticles of Iron Oxide

Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK.
Methods in molecular biology (Clifton, N.J.) (Impact Factor: 1.29). 01/2011; 680:103-15. DOI: 10.1007/978-1-60761-901-7_7
Source: PubMed

ABSTRACT For molecular magnetic resonance imaging (mMRI), microparticles of iron oxide (MPIO) create potent hypointense contrast effects that extend a distance far exceeding their physical size. The potency of the contrast effects derive from their high iron content and are significantly greater than that of ultra-small particles of iron oxide (USPIO), commonly used for MRI. Due to their size and incompressible nature, MPIO are less susceptible to nonspecific vascular egress or uptake by endothelial cells. Therefore, MPIO may be useful contrast agents for detection of endovascular molecular targets by MRI. This Chapter describes the methodology of a novel, functional MPIO probe targeting vascular cell adhesion molecule-1 (VCAM-1), for detection of acute brain inflammation in vivo, at a time when pathology is undetectable by conventional MRI. Protocols are included for conjugation of MPIO to mouse monoclonal antibodies against VCAM-1 (VCAM-MPIO), the validation of VCAM-MPIO binding specificity to activated endothelial cells in vitro, and the application of VCAM-MPIO for in vivo targeted MRI of acute brain inflammation in mice. This functional molecular imaging tool may potentially accelerate accurate diagnosis of early cerebral vascular inflammation by MRI, and guide specific therapy.

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    • "Ultra high-field neuroimaging combined with injections of iron oxide nanoparticles is emerging as a neuroimaging method to visualize inflammatory phenomena at the cellular level by marking activated microglia in early inflammatory stages. This method shows greater regional binding of contrast agent even in the absence of frank disruptions to blood-brain barrier permeability and with greater spatial resolution than Gadolinium contrast approaches (see references [57] [58] [59] [60] for reviews). Magnetic resonance molecular imaging has been used in acute ischemic stroke to identify endothelial activation by targeting biomolecular agents [61]. "
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