MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors.

Enzyme-responsive PARACEST MRI contrast agents: a new biomedical imaging approach for studies of the proteasome.

Yoo B, Raam MS, Rosenblum RM, Pagel MD

Case Center of Imaging Research and Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.

Proteases are important biomarkers for many biological processes and are popular targets for therapeutics investigations. A protease can be detected by monitoring changes in the paramagnetic chemical exchange saturation transfer (PARACEST) effect of a MRI contrast agent that serves as a substrate for the protease. To translate this type of responsive PARACEST MRI contrast agent to in vivo applications, the sensitivity, timing, specificity and validation of the response of the agent must be evaluated. This report demonstrates that PARACEST MRI contrast agents can be used to detect nanomolar concentrations of proteases, can be designed to preferentially detect the protease caspase-3 relative to caspase-8, and can be detected within the 15 min time frame of typical MRI studies. The response can be validated using an unresponsive PARACEST MRI contrast agent as a control. A survey of the MEROPS database shows that this approach may also be applied to detect other proteases, and therefore may represent a new platform technology for studies of the proteasome. Copyright (c) 2007 John Wiley & Sons, Ltd.

Published 7 September 2007 in Contrast Media Mol Imaging, 2(4): 189-198.
Full-text of this article is available online (may require subscription).

© 2005-2008 MRI Research Today. All Rights Reserved.