18F-labelled annexin V: a PET tracer for apoptosis imaging.
Annexin V can be used to detect apoptotic cells in vitro and in vivo, based on its ability to identify extracellular phosphatidylserine, which arises during apoptosis. In the present study, we examined the synthesis of fluorine-18 labelled annexin V as a positron emission tomography tracer for apoptosis imaging. The distribution of [18F]annexin V and technetium-99m labelled annexin V, a well-characterised SPET tracer for apoptosis imaging, was compared. [18F]annexin V was synthesised using N-succinimidyl 4-[18F]fluorobenzoate as an 18F labelling reagent. Synthesised and purified [18F]annexin V was confirmed by SDS-PAGE. In an ex vivo imaging experiment, [18F]annexin V was intravenously injected into rats 24 h after the induction of myocardial ischaemia, and accumulation in the left ventricle was examined. [18F]annexin V accumulated in the infarct area of the left ventricle, where apoptotic cells were observed. In separate experiments, [18F]annexin V or [(99m)Tc]annexin V was intravenously injected into ischaemic or normal animals, and the distribution of the tracers was compared. In ischaemic animals, accumulation of [18F]annexin V and [(99m)Tc]annexin V in the infarct area was about threefold higher than in the non-infarct area. Furthermore, the ratio of accumulation in the normal heart to the blood radioactivity was not significantly different between the tracers. In normal animals, however, the uptake of [18F]annexin V in the liver, spleen and kidney was much lower than that of [(99m)Tc]annexin V. The low uptake of [18F]annexin V in these organs might represent an advantage over [(99m)Tc]annexin V.
Murakami
Yoshihiro
Y
The Medical and Pharmacological Research Center Foundation, Wo32, 925-0613, Inoyama, Hakui, Ishikawa, Japan. murakami@mprcf.or.jp
Takamatsu
Hiroyuki
H
Taki
Junichi
J
Tatsumi
Mitsuyoshi
M
Noda
Akihiro
A
Ichise
Rikiya
R
Tait
Jonathan F
JF
Nishimura
Shintaro
S
D000818:Animals; D017304:Annexin A5 / Q000493:pharmacokinetics*; D017209:Apoptosis; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D008657:Metabolic Clearance Rate; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000378:metabolism*; D009928:Organ Specificity; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
D017304:Annexin A5; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals