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Comparative study of iodine-123-labeled hypericin and 99mTc-labeled hexakis [2-methoxy isobutyl isonitrile] in a rabbit model of myocardial infarction.
|Title||Comparative study of iodine-123-labeled hypericin and 99mTc-labeled hexakis [2-methoxy isobutyl isonitrile] in a rabbit model of myocardial infarction.|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Cona MM, Feng Y, Li Y, Chen F, Vunckx K, Zhou L, Van Slambrouck K, Rezaei A, Gheysens O, Nuyts J, Verbruggen A, Oyen R, Ni Y|
|Journal||Journal of cardiovascular pharmacology|
|Date Published||2013 Sep|
Identification of myocardial infarction (MI) by imaging is critical for clinical management of ischemic heart disease. Iodine-123-labeled hypericin (I-Hyp) is a new potent infarct avid agent. We sought to compare target selectivity and organ distribution between I-Hyp and the myocardial perfusion agent, technetium-99m-labeled hexakis [2-methoxy isobutyl isonitrile] (Tc-Sestamibi) in rabbits with acute MI. Hypericin was radiolabeled with I using iodogen as oxidant, and Tc-Sestamibi was prepared from a commercial kit and radioactive sodium pertechnetate. Rabbits (n = 6) with 24-hour-old MI received I-Hyp intravenously and received Tc-Sestamibi 9 hours later. They were studied by dual-isotope simultaneous acquisition micro single photon emission computed tomography/computed tomography (DISA-μSPECT/CT), tissue gamma counting (TGC), autoradiography, and histology. After purification, I-Hyp was obtained with radiochemical purity around 99%. DISA-μSPECT/CT images showed I-Hyp retention in infarcted but not in normal myocardium. By TGC, accumulation values reached 1.175 ± 0.096 percentage of injected dose per gram (%ID/g) and 0.028 ± 0.007%ID/g in infarcted myocardium and normal myocardium with high tracer concentration in liver, intestines, and gallbladder. Tc-Sestamibi was prepared with radiochemical purity over 95%. DISA-μSPECT/CT showed no accumulation in MI and high initial radioactivity levels in normal myocardium that were rapidly cleared as confirmed by TGC (0.011 ± 0.003%ID/g). Liver and intestines were clearly visualized. By TGC, gallbladder and kidneys show moderate Tc-Sestamibi uptake. The selectivity of I-Hyp for infarcted myocardium and Tc-Sestamibi for normal myocardium was confirmed. I-Hyp distribution in rabbits is characterized by hepatobiliary excretion. Tc-Sestamibi undergoes hepatorenal elimination.
|Alternate Journal||J. Cardiovasc. Pharmacol.|