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
Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland.
Cardiovasc Res. 2015 Feb 1;105(2):213-22. doi: 10.1093/cvr/cvu257. Epub 2014 Dec 23.
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.
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.
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.
在这项工作中，我们提供了对血管紧张素Ⅱ输注小鼠腹主动脉夹层形态的新见解。我们证明了为什么它们的形状有很大的差异，并且与人类不同，它们位于肾上而不是肾下。
我们结合了基于同步加速器的超高分辨率离体成像（相衬 X 射线断层显微镜）与体内成像（高频超声和对比增强微 CT）和图像引导组织学。在所有小鼠中，我们观察到腹腔动脉口附近的腹主动脉中层有一个撕裂。我们独立发现，与人类动脉瘤典型的逐渐管腔扩张不同，血管紧张素Ⅱ诱导的小鼠夹层动脉瘤的外径增加与一个或多个壁内血肿有关。这些是由于小肾上侧支近腔口处中膜破裂引起的，而这些小肾上侧支从未被现有的小动物成像技术检测到。腹腔动脉口附近的撕裂导致明显的管腔扩张，而壁内血肿导致主动脉左肾上侧的外膜夹层。延伸至胸主动脉的动脉瘤中破裂的分支数量较多，这解释了观察到的动脉瘤形状的可变性。
我们的结果首次描述了小鼠腹主动脉夹层中明显的管腔扩张、肾上分支破裂和壁内血肿形成。此外，我们验证并证明了相衬 X 射线断层显微镜在心血管小动物应用中的巨大潜力。
