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Arterioscler Thromb Vasc Biol. 2016 Apr;36(4):673-81. doi: 10.1161/ATVBAHA.116.307211. Epub 2016 Feb 18.

Ascending Aortic Aneurysm in Angiotensin II-Infused Mice: Formation, Progression, and the Role of Focal Dissections.

Author information

1
From the Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (B.T., R.A.F.-S., L.A., N.S.); IBiTech-bioMMeda, Ghent University-iMinds Medical IT, Ghent, Belgium (B.T., P.S.); School of Life Sciences, PTEC GE, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (A.P.); Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland (A.P.); Histology Core Facility, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (J.S.-D.); Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland (A.A., M.F.M.S.); and Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland (M.F.M.S.). bram.trachet@epfl.ch.
2
From the Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (B.T., R.A.F.-S., L.A., N.S.); IBiTech-bioMMeda, Ghent University-iMinds Medical IT, Ghent, Belgium (B.T., P.S.); School of Life Sciences, PTEC GE, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (A.P.); Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland (A.P.); Histology Core Facility, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland (J.S.-D.); Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland (A.A., M.F.M.S.); and Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland (M.F.M.S.).

Abstract

OBJECTIVE:

To understand the anatomy and physiology of ascending aortic aneurysms in angiotensin II-infused ApoE(-/-) mice.

APPROACH AND RESULTS:

We combined an extensive in vivo imaging protocol (high-frequency ultrasound and contrast-enhanced microcomputed tomography at baseline and after 3, 10, 18, and 28 days of angiotensin II infusion) with synchrotron-based ultrahigh resolution ex vivo imaging (phase contrast X-ray tomographic microscopy) in n=47 angiotensin II-infused mice and 6 controls. Aortic regurgitation increased significantly over time, as did the luminal volume of the ascending aorta. In the samples that were scanned ex vivo, we observed one or several focal dissections, with the largest located in the outer convex aspect of the ascending aorta. The volume of the dissections moderately correlated to the volume of the aneurysm as measured in vivo (r(2)=0.46). After 3 days of angiotensin II infusion, we found an interlaminar hematoma in 7/12 animals, which could be linked to an intimal tear. There was also a significant increase in single laminar ruptures, which may have facilitated a progressive enlargement of the focal dissections over time. At later time points, the hematoma was resorbed and the medial and adventitial thickness increased. Fatal transmural dissection occurred in 8/47 mice at an early stage of the disease, before adventita remodeling.

CONCLUSIONS:

We visualized and quantified the dissections that lead to ascending aortic aneurysms in angiotensin II-infused mice and provided unique insight into the temporal evolution of these lesions.

KEYWORDS:

aortic aneurysm; aortic dissection; ascending aorta; cardiovascular imaging; mouse models of human disease

PMID:
26891740
DOI:
10.1161/ATVBAHA.116.307211
[Indexed for MEDLINE]
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