Dynamic expression of tenascin-C after myocardial ischemia and reperfusion: Assessment by125i-anti-tenascin-c antibody imaging

Tenascin-C, an extracellular matrix glycoprotein, appears only in the early stages of embryonic development. It is not normally expressed in the adult heart but does reappear transiently in distinct areas in association with active tissue remodeling. The aim of this study was to explore serial changes in the expression of tenascin-C after myocardial ischemia and reperfusion, using 125I-labeled anti-tenascin-C antibody (125I-TNC-Ab) in a rat model of acute ischemia and reperfusion. Methods: The left coronary artery was occluded for 20or30min, followedbyreperfusion for 1, 3, or 7 d in rats with 20 min of ischemia and for 1, 3, 7, 14, or 28 d inrats with30min ofischemia.Atthe timeofthe study,125I-TNC-Ab (1.0-2.5 MBq) was injected. Three to 5 h later, to verify the area at risk,99mTc- methoxyisobutylisonitrile (100-200 MBq) was injected intravenously just after the left coronary artery reocclusion and the rats were sacrificed 1 min later. Dual-tracer autoradiography was performed to assess125I-TNC-Ab uptake and the area at risk. Results: In rats with 20 min of ischemia, 125I-TNC-Ab uptake peaked at 3 d after reperfusion, followed by faint uptake after 7 d (uptake ratios at 1, 3, and 7 d after reperfusion were 1.81 ± 0.53, 2.46 ± 0.79, and 1.23 ± 0.17, respectively [P < 0.05 vs. 3 d]). In rats with 30 min of ischemia, uptake was high at 1 and 3 d after reperfusion (2.99 ± 0.90 and 2.71 ± 0.80, respectively), decreased at 7 and 14 d (1.94 ± 0.23 and 2.06 ± 0.37, respectively), and was weak at 28 d (1.47 ± 0.27, P < 0.005 vs. 1 d, P < 0.05 vs. 3 d). Conclusion: These data indicate that125I-TNC-Ab imaging may be a way to monitor myocardial injury and its repair process after ischemia and reperfusion by visualizing tenascin-C expression. COPYRIGHT © 2010 by the Society of Nuclear Medicine, Inc.