Abstract 1913: Ezetimibe Effectively Prevents Atherosclerotic Plaque Formation as Demonstrated by High Field MRI
Aim: To evaluate the effect of Ezetimibe (EZE) treatment on atherosclerotic plaque formation in apoE deficient (apoE−/−) mice and to determine changes in plaque size detectable by high field magnetic resonance imaging (MRI).
Methods: Ten apoE−/− mice were fed with high fat diet (21%fat) without EZE (n=5) and with EZE medication (5μg/kg/d, n=5). After 12–15 month long term feeding all mice underwent high-field MR imaging (Bruker Pharmescan 70/16 AS) of the aortic arch. An ECG- and respiratory-triggered T1-weighted 3D spin echo sequence was used (TR/TE/flip angle: 500ms/15.6ms/90°; spatial resolution 110×110μm, slice thickness 250μm). Measurements of vessel lumen area and wall thickness were performed offline (ImageJ 1.33). After exsanguination, plaque formation of the aortic arch was histologically analyzed with the histology sections being closely matched to the MR images.
Results: In comparison to untreated mice, EZE-fed mice demonstrated a significantly increased lumen area (EZE: 2.75±0.39mm2 versus 1.7±0.42 mm2, p<0.01) and a significantly decreased vessel wall thickness (EZE: 0.23±0.06mm versus 0.55±0.11mm, p<0.001) on MR images. The MRI findings were confirmed by histology measurements for both parameters in untreated and EZE-fed mice (lumen area: EZE: 4.59±0.92mm2 versus 4.08±0.45 mm2, p<0.01; vessel wall thickness: EZE: 0.17±0.04mm versus 0.41±0.1 mm, p<0.01, respectively.
Conclusion: Treatment with ezetimibe effectively prevented atherosclerotic plaque formation in apoE−/−mice. In-vivo high-field MRI proved to be a valuable method for the non-invasive monitoring of atherosclerotic plaque size even in the great vessels close to the heart.