title: 14C-Methionine uptake as a potential marker of inflammatory processes after myocardial ischemia and reperfusion.
abstract: A relationship between l-[methyl-(11)C]methionine ((11)C-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 (14)C-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, (14)C-methionine (0.74 MBq) and (201)Tl (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 (99m)Tc-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 (14)C-methionine (uptake ratio, 0.71 ± 0.13) and (201)Tl uptake were reduced in the area at risk at 1 d after reperfusion. However, 3 d after reperfusion, an increased (14)C-methionine uptake (1.79 ± 0.23) was observed corresponding to the area of still-reduced (201)Tl uptake, and the (14)C-methionine uptake gradually declined until 28 d. The increased (14)C-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.
  
  
  CONCLUSIONS
  (14)C-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.
authors: Department of Nuclear Medicine, Kanazawa University Hospital, Kanazawa, Japan. taki@med.kanazawa-u.ac.jp
authors: Junichi
authors: J
authors: Taki
authors: Hiroshi
authors: H
authors: Wakabayashi
authors: Anri
authors: A
authors: Inaki
authors: Kyoko
authors: K
authors: Imanaka-Yoshida
authors: Michiaki
authors: M
authors: Hiroe
authors: Kazuma
authors: K
authors: Ogawa
authors: Miyako
authors: M
authors: Morooka
authors: Kazuo
authors: K
authors: Kubota
authors: Kazuhiro
authors: K
authors: Shiba
authors: Toshimichi
authors: T
authors: Yoshida
authors: Seigo
authors: S
authors: Kinuya
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D001345:Autoradiography; D015415:Biomarkers / Q000378:metabolism; D002250:Carbon Radioisotopes; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D007249:Inflammation / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008715:Methionine / Q000187:drug effects / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D019210:Troponin I / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D000199:Actins; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D002250:Carbon Radioisotopes; D008715:Methionine; D019210:Troponin I; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C498862:Acta2 protein, rat