14C-Methionine Uptake as a Potential Marker of Inflammatory Processes After Myocardial Ischemia and Reperfusion

Journal of Nuclear Medicine

Kazuma Ogawa¹  Miyako Morooka¹  Kyoko Imanaka-Yoshida¹  Michiaki Hiroe¹  Seigo Kinuya¹  Kazuo Kubota¹  Hiroshi Wakabayashi¹  Anri Inaki¹  Junichi Taki¹  Kazuhiro Shiba¹  Toshimichi Yoshida¹ 

关键词: methionine;    myocardial ischemia;    reperfusion;    myocardial infarction;    macrophage;   

DOI  :  10.2967/jnumed.112.112060

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

A relationship between l-[methyl-11C]methionine (11C-methionine) uptake and angiogenesis has been suggested in gliomas. However, methionine uptake in myocardial ischemia and reperfusion has received little attention. We investigated the serial changes and mechanisms of 14C-methionine uptake in a rat model of myocardial ischemia and reperfusion. Methods: The left coronary artery was occluded for 30 min, followed by reperfusion for 1–28 d. At the time of the study, 14C-methionine (0.74 MBq) and 201Tl (14.8 MBq) were injected intravenously at 20 and 10 min before sacrifice, respectively. One minute before sacrifice, the left coronary artery was reoccluded, and 99mTc-hexakis-2-methoxyisobutylisonitrile (150–180 MBq) was injected to verify the area at risk. Histologic sections of the heart were immunohistochemically analyzed using anti-CD68, anti–smooth-muscle α-actin (SMA), and antitroponin I and compared with the autoradiography findings. Results: Both 14C-methionine (uptake ratio, 0.71 ± 0.13) and 201Tl uptake were reduced in the area at risk at 1 d after reperfusion. However, 3 d after reperfusion, an increased 14C-methionine uptake (1.79 ± 0.23) was observed corresponding to the area of still-reduced 201Tl uptake, and the 14C-methionine uptake gradually declined until 28 d. The increased 14C-methionine uptake area at 3 and 7 d corresponded well to the macrophage infiltrations demonstrated by positive CD68 staining. Anti-SMA staining appeared at 7 d, after which CD68 staining was gradually replaced by the SMA staining, suggesting that methionine uptake in the early phase after ischemia and reperfusion might reflect inflammatory activity. Conclusion: 14C-methionine accumulated in the infarcted area, and its uptake corresponded closely to macrophage infiltration at 3–7 d after reperfusion. Methionine imaging may be useful for inflammatory imaging early after myocardial infarction.

【 授权许可】

Unknown