Title:Dissecting abdominal aortic aneurysm in Angiotensin II-infused mice: the importance of imaging
Volume: 21
Issue: 28
Author(s): Bram Trachet, Rodrigo A. Fraga-Silva, Alessandra Piersigilli, Patrick Segers and Nikolaos Stergiopulos
Affiliation:
Keywords:
Abdominal aortic aneurysms, small animal imaging, dissecting aneurysm, high-frequency ultrasound, PCXTM, micro-CT, MRI,
angiotensin II, mouse model.
Abstract: Introduction. Since the initial publication in 2000, Angiotensin II-infused mice have become one of the
most popular models to study abdominal aortic aneurysm in a pre-clinical setting. We recently used phase contrast
X-ray based computed tomography to demonstrate that these animals develop an apparent luminal dilatation and an
intramural hematoma, both related to mural ruptures in the tunica media in the vicinity of suprarenal side branches.
Aims. The aim of this narrative review was to provide an extensive overview of small animal applicable techniques
that have provided relevant insight into the pathogenesis and morphology of dissecting AAA in mice, and to relate
findings from these techniques to each other and to our recent PCXTM-based results. Combining insights from recent and consolidated
publications we aimed to enhance our understanding of dissecting AAA morphology and anatomy.
Results and conclusion. We analyzed in vivo and ex vivo images of aortas obtained from macroscopic anatomy, histology, highfrequency
ultrasound, contrast-enhanced micro-CT, micro-MRI and PCXTM. We demonstrate how in almost all publications the aorta
has been subdivided into a part in which an intact lumen lies adjacent to a remodeled wall/hematoma, and a part in which elastic lamellae
are ruptured and the lumen appears to be dilated. We show how the novel paradigm fits within the existing one, and how 3D images can
explain and connect previously published 2D structures. We conclude that PCXTM-based findings are in line with previous results, and
all evidence points towards the fact that dissecting AAAs in Angiotensin II-infused mice are actually caused by ruptures of the tunica
media in the immediate vicinity of small side branches.
