RT Journal Article
SR Electronic
T1 <sup>14</sup>C-Methionine Uptake as a Potential Marker of Inflammatory Processes After Myocardial Ischemia and Reperfusion
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 431
OP 436
DO 10.2967/jnumed.112.112060
VO 54
IS 3
A1 Junichi Taki
A1 Hiroshi Wakabayashi
A1 Anri Inaki
A1 Kyoko Imanaka-Yoshida
A1 Michiaki Hiroe
A1 Kazuma Ogawa
A1 Miyako Morooka
A1 Kazuo Kubota
A1 Kazuhiro Shiba
A1 Toshimichi Yoshida
A1 Seigo Kinuya
YR 2013
UL http://jnm.snmjournals.org/content/54/3/431.abstract
AB 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.