Localization of Deoxyglucose and Annexin A5 in Experimental Atheroma Correlates with Macrophage Infiltration but not Lipid Deposition in the Lesion
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The aim of this study was to understand the relationship of lipid deposition to the macrophage content, macrophage metabolism, and apoptosis in plaque. We compared the uptake of 2-deoxy-2-fluoro-D-[14C]glucose ([14C]FDG) and [99mTc]HYNIC-annexin V ([99mTc]annexin A5) with the lesion histology in apolipoprotein E knockout (apoE−/−) mice.
Male apoE−/− mice (n = 9) were injected with [14C]FDG and [99mTc]annexin A5. Cryostat sections of aorta samples (n = 49) were used for dual-tracer autoradiography, and regional tracer uptake levels were evaluated. Lesions were identified histologically with Movat's pentachrome (AHA lesion phenotypes), Mac-2 staining (macrophage infiltration) and Oil Red O staining (lipid deposition).
The highest uptakes of [14C]FDG (3.10 ± 1.50 %ID × kilogram per square millimeter) and [99mTc]annexin A5 (0.49 ± 0.20 %ID × kilogram per square millimeter) were shown in atheromatous lesions (types III and IV). Each tracer uptake showed better correlation with macrophage infiltration than lipid deposition ([14C]FDG, r = 0.44 vs. r = 0.14; [99mTc]annexin A5, r = 0.65 vs. r = 0.48).
Both tracers were concentrated in type III and IV atheromatous lesions which corresponded to macrophage infiltration rather than lipid deposition.
Key wordsAtherosclerosis Imaging Nuclear medicine FDG Annexin A5
- [99mTc]annexin A5
- apoE−/− mice
Apolipoprotein E knockout mice
Positron emission tomography
Magnetic resonance image
Transient ischemic attack
Region of interest
Acute coronary syndrome