RT Journal Article SR Electronic T1 Visualization of Myocardial Phosphoinositide Turnover with 1-[1-11C]-Butyryl-2-Palmitoyl-rac-Glycerol in Rats with Myocardial Infarction JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 2063 OP 2068 VO 41 IS 12 A1 Chida, Masanobu A1 Kagaya, Yutaka A1 Imahori, Yoshio A1 Namiuchi, Shigeto A1 Fujii, Ryou A1 Fukuchi, Mitsumasa A1 Takahashi, Chikako A1 Tezuka, Fumiaki A1 Ido, Tatsuo A1 Shirato, Kunio YR 2000 UL http://jnm.snmjournals.org/content/41/12/2063.abstract AB Phosphoinositide turnover mediates the signaling of angiotensin II, which plays a pivotal role in ventricular remodeling after myocardial infarction (MI). We tested the hypothesis that phosphoinositide turnover can be visualized by 1-[1-11C]butyryl-2-palmitoyl-rac-glycerol (11C-DAG) in both infarcted and noninfarcted myocardium after MI in rats. Methods: Rats received an injection of 11C-DAG 7 d after left coronary artery ligation, and myocardial lipids were extracted from both infarcted and noninfarcted areas of myocardium (n = 3). Metabolites of 11C-DAG were determined by thin-layer chromatography. Quantitative autoradiography of hearts was performed to visualize myocardial phosphoinositide turnover in rats that received an injection of 11C-DAG 1 d (n = 3) and 7 d (n = 5) after MI and 7 d after a sham operation (n = 3). Quantitative autoradiography with 201TlCl was also performed to evaluate myocardial blood flow in rats 7 d after MI (n = 3). Cells occupying the infarcted myocardium were identified by immunohistochemistry. Results: The radioactivity incorporated into the intermediates of phosphoinositide turnover was predominant in both the infarcted (67.1% ± 5.2% of the total activity) and the noninfarcted (57.4% ± 3.2%) myocardium. 11C-DAG radioactivity in the infarcted region normalized to that in the noninfarcted region was 1.09 ± 0.04 in rats 7 d after MI, which was significantly higher than that in rats 1 d after MI (0.38 ± 0.03, P < 0.001). 201Tl radioactivity in the infarcted region normalized to that in the noninfarcted region was only 0.19 ± 0.01 7 d after MI. 11C-DAG radioactivity in the noninfarcted region normalized to that in the right ventricular free wall tended to be increased in rats 1 and 7 d after MI compared with the sham-operated rats; the differences, however, were not statistically significant (1.30 ± 0.15, 1.20 ± 0.07, and 1.13 ± 0.02, respectively). Immunohistochemistry revealed that abundant fibroblasts, myofibroblasts, and macrophages occupied the infarcted myocardium 7 d after MI, but the cellularity was low during the first day after MI. Conclusion: These data suggest that 11C-DAG may be useful for visualizing regions with activated phosphoinositide turnover after MI. Because wound healing and fibrogenic processes are important factors of ventricular remodeling, 11C-DAG and PET may offer new information benefiting patient management after MI.