title: Dissecting abdominal aortic aneurysm in Ang II-infused mice: suprarenal branch ruptures and apparent luminal dilatation.
abstract: OBJECTIVE
  In this work, we provide novel insight into the morphology of dissecting abdominal aortic aneurysms in angiotensin II-infused mice. We demonstrate why they exhibit a large variation in shape and, unlike their human counterparts, are located suprarenally rather than infrarenally.
  
  
  RESULTS
  We combined synchrotron-based, ultra-high resolution ex vivo imaging (phase contrast X-Ray tomographic microscopy) with in vivo imaging (high-frequency ultrasound and contrast-enhanced micro-CT) and image-guided histology. In all mice, we observed a tear in the tunica media of the abdominal aorta near the ostium of the celiac artery. Independently we found that, unlike the gradual luminal expansion typical for human aneurysms, the outer diameter increase of angiotensin II-induced dissecting aneurysms in mice was related to one or several intramural haematomas. These were caused by ruptures of the tunica media near the ostium of small suprarenal side branches, which had never been detected by the established small animal imaging techniques. The tear near the celiac artery led to apparent luminal dilatation, while the intramural haematoma led to a dissection of the tunica adventitia on the left suprarenal side of the aorta. The number of ruptured branches was higher in those aneurysms that extended into the thoracic aorta, which explained the observed variability in aneurysm shape.
  
  
  CONCLUSIONS
  Our results are the first to describe apparent luminal dilatation, suprarenal branch ruptures, and intramural haematoma formation in dissecting abdominal aortic aneurysms in mice. Moreover, we validate and demonstrate the vast potential of phase contrast X-ray tomographic microscopy in cardiovascular small animal applications.
authors.affiliation: IBiTech-bioMMeda, Ghent University-iMinds Medical IT, Ghent, Belgium Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland bram.trachet@ugent.be bram.trachet@epfl.ch.
authors.forename: Bram
authors.initials: B
authors.lastname: Trachet
authors.affiliation: Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Fraga-Silva
authors.affiliation: School of Life Sciences, PTEC GE, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Institute of Animal Pathology, University of Bern, Bern, Switzerland.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Piersigilli
authors.affiliation: INSERM, Paris Cardiovascular Research Center (PARCC), Université Paris Descartes, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Tedgui
authors.affiliation: Histology Core Facility, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Jessica
authors.initials: J
authors.lastname: Sordet-Dessimoz
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland.
authors.forename: Alberto
authors.initials: A
authors.lastname: Astolfo
authors.affiliation: Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium.
authors.forename: Carole
authors.initials: C
authors.lastname: Van der Donckt
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland Centre d'Imagerie BioMédicale, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Modregger
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland.
authors.forename: Marco F M
authors.initials: MF
authors.lastname: Stampanoni
authors.affiliation: IBiTech-bioMMeda, Ghent University-iMinds Medical IT, Ghent, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Segers
authors.affiliation: Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Stergiopulos
mesh_terms: D000784:Aortic Dissection / Q000473:pathology*; D017542:Aneurysm, Ruptured / Q000473:pathology*; D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology*; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology*; D003287:Contrast Media; D004108:Dilatation, Pathologic / Q000188:drug therapy*; D004195:Disease Models, Animal; D008297:Male; D008810:Mice, Inbred C57BL
chemical_list: D003287:Contrast Media; D000804:Angiotensin II
keywords: Abdominal aortic aneurysm; Angiotensin II; Grating interferometry; Mouse model; X-ray CT