RT Journal Article SR Electronic T1 Cardioprotective Effects of Erythropoietin in Rats Subjected to Ischemia–Reperfusion Injury: Assessment of Infarct Size with 99mTc-Annexin V JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1694 OP 1700 DO 10.2967/jnumed.107.050260 VO 49 IS 10 A1 Tomoki Doue A1 Katsuichi Ohtsuki A1 Kazuma Ogawa A1 Masashi Ueda A1 Akihiro Azuma A1 Hideo Saji A1 Harry W. Strauss A1 Hiroaki Matsubara YR 2008 UL http://jnm.snmjournals.org/content/49/10/1694.abstract AB Administration of erythropoietin (EPO) during or immediately after myocardial ischemia can reduce subsequent myocardial apoptosis, a key phenomenon in myocardial ischemia–reperfusion injury. In this study, we assessed the effect of EPO on 99mTc-annexin V myocardial uptake and whether the accumulation of 99mTc-annexin V can predict cardiac remodeling and functional deterioration. Methods: Eighteen rats with left coronary artery (LCA) occlusion were randomized to receive either an intravenous injection of EPO (EPO group) or saline (nontherapy [nT] group) immediately after release of the occlusion. After 20 min of LCA occlusion and 30 min of reperfusion, the rats were injected with 99mTc-annexin V. One hour after 99mTc-annexin V injection, the LCA was reoccluded and 201Tl was injected intravenously, and the rats were sacrificed 1 min later. The heart was removed and sectioned, and dual-tracer autoradiography was performed to evaluate the distribution of the area at risk (defined on the thallium autoradiograph) and the area of apoptosis (defined on the annexin autoradiograph). Adjacent histologic specimens had deoxyuridine triphosphate nick-end labeling (TUNEL) staining to confirm the presence of apoptosis and were compared with autoradiography. Another 16 rats were randomized to EPO and nT groups and underwent echocardiography immediately after release of the LCA occlusion and at 2 and 4 wk after surgery. Results: The areas of 99mTc-annexin V accumulation in the EPO group were smaller than those in the nT group, though the 201Tl defect areas of these 2 groups were comparable (area ratio, 0.318 ± 0.038 vs. 0.843 ± 0.051, P < 0.001, for annexin and 24.8 ± 2.1 vs. 25.9 ± 2.6 mm2, P = NS, for thallium). 99mTc-annexin V accumulation correlated with the density of TUNEL-positive cells (r = 0.886, P < 0.001). In the nT group, left ventricular end-diastolic dimension (Dd) increased from baseline at 2 wk by 34.7% ± 3.8% and remained stable at 34.9% ± 5.0% at 4 wk after coronary occlusion. In the EPO group, Dd increased by 8.5% ± 2.1% (P < 0.01 vs. nT at 2 wk) and 13.2% ± 2.8% (P < 0.01 vs. nT at 4 wk). In the nT group, the left ventricular percentage of fractional shortening decreased by 42.2% ± 3.4% and 52.9% ± 3.4% at 2 and 4 wk, respectively, whereas in the EPO group it decreased 9.0% ± 1.9% at 2 wk (P < 0.01 vs. nT at 2 wk) and 11.1% ± 6.7% at 4 wk (P < 0.01 vs. nT at 4 wk). Conclusion: This study demonstrated that a single treatment with EPO immediately after release of coronary ligation suppressed cardiac remodeling and functional deterioration. 99mTc-annexin V autoradiographs and TUNEL staining confirm that this change is due to a decrease in the extent of myocardial apoptosis in the ischemic/reperfused region.