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Updated: Mar 23, 2026
Generation and 3-Dimensional Quantitation of Arterial Lesions in Mice Using Optical Projection Tomography
Published on: May 26, 2015
αVβ3 integrin-targeted microSPECT/CT imaging of inflamed atherosclerotic plaques in mice
David Vancraeynest1,2, Véronique Roelants3, Caroline Bouzin4
1Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium. david.vancraeynest@uclouvain.be.
Background:
αVβ3-integrin is expressed by activated endothelial cells and macrophages in atherosclerotic plaques and may represent a valuable marker of high-risk plaques. We evaluated (99m)Tc-maraciclatide, an integrin-specific tracer, for imaging vascular inflammation in atherosclerotic lesions in mice.
Methods:
Apolipoprotein E-negative (ApoE(-/-)) mice on a Western diet (n = 10) and normally fed adult C57BL/6 control mice (n = 4) were injected with (99m)Tc-maraciclatide (51.8 ± 3.7 MBq). A blocking peptide was infused in three ApoE(-/-) mice; this condition served as another control. After 90 min, the animals were imaged via single-photon emission computed tomography (SPECT). While maintained in the same position, the mice were transferred to computed tomography (CT) to obtain contrast-enhanced images of the aortic arch. Images from both modalities were fused, and signal was quantified in the aortic arch and in the vena cava for subtraction of blood-pool activity. The aorta was carefully dissected after imaging for gamma counting, autoradiography, and histology.
Results:
Tracer uptake was significantly higher in ApoE(-/-) mice than in both groups of control mice (1.56 ± 0.33 vs. 0.82 ± 0.24 vs. 0.98 ± 0.11, respectively; P = 0.006). Furthermore, higher tracer activity was detected via gamma counting in the aorta of hypercholesterolemic mice than in both groups of control mice (1.52 ± 0.43 vs. 0.78 ± 0.19 vs. 0.47 ± 0.31 (99m)Tc-maraciclatide %ID/g, respectively; P = 0.018). Autoradiography showed significantly higher tracer uptake in the atherosclerotic aorta than in the control aorta (P = 0.026). Finally, in the atherosclerotic aorta, immunostaining indicated that the integrin signal came predominantly from macrophages and was correlated with the macrophage CD68 immunomarker (r = 0.73).
Conclusions:
(99m)Tc-maraciclatide allows in vivo detection of inflamed atherosclerotic plaques in mice and may represent a non-invasive approach for identifying high-risk plaques in patients.
