Postconditioning Accelerates Myocardial Inflammatory Resolution Demonstrated by 14C-Methionine Imaging and Attenuates Ventricular Remodeling After Ischemia and Reperfusion

• Published in: Circulation Journal Vol. 83; no. 12; pp. 2520 - 2526
• Main Authors: Taki, Junichi, Inaki, Anri, Wakabayashi, Hiroshi, Matsunari, Ichiro, Imanaka-Yoshida, Kyoko, Ogawa, Kazuma, Hiroe, Michiaki, Shiba, Kazuhiro, Kinuya, Seigo
• Format: Journal Article
• Language: English
• Published: The Japanese Circulation Society 25.11.2019
• Subjects: Methionine; Myocardial infarction; Post infarct inflammation; Postconditioning; Ventricular remodeling
• ISSN: 1346-9843; 1347-4820; 1347-4820
• DOI: 10.1253/circj.CJ-19-0462

Background:Methionine uptake after myocardial infarction has been proven to reflect myocardial inflammation. The effect of postconditioning on the post-infarction inflammatory process, however, remains to be elucidated.Methods and Results:In control (n=22) and postconditioning rats (n=23), the left coronary artery was occluded for 30 min, followed by reperfusion for 1, 3, 7, and 14 days. Postconditioning was performed immediately following the reperfusion. 14C-methinine (0.74 MBq) and 201Tl (14.8 MBq) were injected 20 and 10 min prior to sacrifice, respectively. One minute before sacrifice, 150–180 MBq of 99 mTc-MIBI was injected immediately following the re-occlusion of the left coronary artery to verify the area at risk, and left ventricular triple-tracer autoradiography was performed. To examine the ventricular remodeling, echocardiography was performed 2 months after reperfusion in both groups (n=6 each). In the control rats, the methionine uptake ratios on days 1, 3, 7, and 14 were 0.74±0.12, 1.85±0.16, 1.48±0.10, 1.25±0.04, respectively. With postconditioning, methionine uptake was similar on day 3 (1.90±0.21), but was lower on day 7 (1.23±0.22, P<0.05) and day 14 (1.08±0.09, P<0.005). Echocardiography revealed that postconditioning reduced the ventricular end-diastolic (0.97±0.16 to 0.78±0.12 cm, P<0.05) and systolic (0.85±0.21 to 0.55±0.23 cm, P<0.05) dimensions and improved ventricular percentage fractional shortening (12±6.2 to 29±12 %, P=0.01).Conclusions: 14C-methinine imaging revealed that postconditioning accelerated resolution of inflammation and attenuated ventricular remodeling.