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Magn Reson Med. 2011 Jan;65(1):239-49. doi: 10.1002/mrm.22597.

Indirectly probing Ca(2+) handling alterations following myocardial infarction in a murine model using T(1)-mapping manganese-enhanced magnetic resonance imaging.

Author information

1
Small Animal Imaging, Department of Radiology, Medical College of Georgia, Augusta, Georgia 30912, USA.

Abstract

Prolonged ischemia causes cellular necrosis and myocardial infarction (MI) via intracellular calcium (Ca(2+)) overload. Manganese-enhanced MRI indirectly assesses Ca(2+) influx movement in vivo as manganese (Mn(2+)) is a Ca(2+) analog. To characterize myocardial Mn(2+) efflux properties, T(1)-mapping manganese-enhanced MRI studies were performed on adult male C57Bl/6 mice in which Ca(2+) efflux was altered using pharmacological intervention agents or MI-inducing surgery. Results showed that (1) Mn(2+) efflux rate increased exponentially with increasing Mn(2+) doses; (2) SEA0400 (a sodium-calcium exchanger inhibitor) decreased the rate of Mn(2+) efflux; and (3) dobutamine (a positive inotropic agent) increased the Mn(2+) efflux rate. A novel analysis technique also delineated regional features in the MI mice, which showed an increased Mn(2+) efflux rate in the necrosed and peri-infarcted tissue zones. The T(1)-mapping manganese-enhanced MRI technique characterized alterations in myocardial Mn(2+) efflux rates following both pharmacologic intervention and an acute MI. The Mn(2+) efflux results were consistent with those in ex vivo studies showing an increased Ca(2+) concentration under similar conditions. Thus, T(1)-mapping manganese-enhanced MRI has the potential to indirectly identify and quantify intracellular Ca(2+) handling in the peri-infarcted tissue zones, which may reveal salvageable tissue in the post-MI myocardium.

PMID:
20872864
DOI:
10.1002/mrm.22597
[Indexed for MEDLINE]
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