Synchrotron-based visualization and segmentation of elastic lamellae in the mouse carotid artery during quasi-static pressure inflation

This dataset contains images that were obtained during quasi-static pressure inflation of mouse carotid arteries. Images were taken with phase propagation imaging at the X02DA TOMCAT beamline of the Swiss Light Source synchrotron at the Paul Scherrer Institute in Villigen, Switzerland. Scans of n=12 left carotid arteries (n-6 Apoe-deficient mice, n=6 wild-type mice, all on a C57Bl6J background) were taken at pressure levels of 0, 10, 20, 30, 40, 50, 70, 90 and 120 mmHg. For analysis we selected 75 images from the center of each stack (starting at the center of the stack, and skipping 2 of every three images in both cranial and caudal axial directions) for each sample and for each pressure level, resulting in a total of 75 x 12 x 9 = 8100 analyzed images from 108 different scans. Segmentation, 3D visualization and geometric analysis is presented in the corresponding manuscript. Files are uploaded in 16bit .tif format and are named: mouseid_pressurelevel_stacknumber, with mouseid consisting of either Apoe (Apoe-deficient) or Bl (wild-type) and the mouse number, pressurelevel varies from P0 to P120 and stacknumber indicates which image from the stack has been uploaded

Synchrotron-based phase contrast imaging of cardiovascular tissue in mice-grating interferometry or phase propagation?

Synchrotron-based x-ray phase-contrast imaging allows for detailed 3D insight into the microstructure of soft tissue and is increasingly used to improve our understanding of mouse models of cardiovascular disease. Two techniques dominate the field: grating interferometry, with superior density contrast at mid to lower microscopic resolutions, and propagation-based phase contrast, facilitating high-resolution tissue imaging. The choice between these techniques depends on which features one is interested in visualizing and is thus highly sample-dependent. In this manuscript we systematically evaluate the advantages and disadvantages of grating interferometry and propagation-based phase contrast for the specific application of pre-clinical cardiovascular tissue. We scanned samples obtained from 5 different mouse models of cardiovascular disease, ranging from carotid plaques over ascending and abdominal aortic aneurysms to hypertrophic hearts. Based on our findings we discuss in detail how synchrotron-based imaging can be used to increase our understanding of the anatomy and biomechanics of cardiovascular disease in mice. We also present a flowchart that can help future users to select the best synchrotron-based phase contrast technique for their pre-clinical cardiovascular samples

Co-localization of microstructural damage and excessive mechanical strain at aortic branches in angiotensin-II-infused mice

Animal models of aortic aneurysm and dissection can enhance our limited understanding of the etiology of these lethal conditions particularly because early-stage longitudinal data are scant in humans. Yet, the pathogenesis of often-studied mouse models and the potential contribution of aortic biomechanics therein remain elusive. In this work, we combined micro-CT and synchrotron-based imaging with computational biomechanics to estimate in vivo aortic strains in the abdominal aorta of angiotensin-II-infused ApoE-deficient mice, which were compared with mouse-specific aortic microstructural damage inferred from histopathology. Targeted histology showed that the 3D distribution of micro-CT contrast agent that had been injected in vivo co-localized with precursor vascular damage in the aortic wall at 3 days of hypertension, with damage predominantly near the ostia of the celiac and superior mesenteric arteries. Computations similarly revealed higher mechanical strain in branching relative to non-branching regions, thus resulting in a positive correlation between high strain and vascular damage in branching segments that included the celiac, superior mesenteric, and right renal arteries. These results suggest a mechanically driven initiation of damage at these locations, which was supported by 3D synchrotron imaging of load-induced ex vivo delaminations of angiotensin-II-infused suprarenal abdominal aortas. That is, the major intramural delamination plane in the ex vivo tested aortas was also near side branches and specifically around the celiac artery. Our findings thus support the hypothesis of an early mechanically mediated formation of microstructural defects at aortic branching sites that subsequently propagate into a macroscopic medial tear, giving rise to aortic dissection in angiotensin-II-infused mice

Early Morphofunctional Changes in AngII-Infused Mice Contribute to Regional Onset of Aortic Aneurysm and Dissection

Aortic aneurysms and dissections are silent and lethal conditions, whose pathogenesis remains incompletely understood. Although angiotensin II (AngII)-infused ApoE-/- mice have been widely used to study aortic aneurysm and dissection, early morphofunctional alterations preceding the onset of these conditions remain unknown. The goal of this study was to unveil early morphofunctional changes underlying the onset of aneurysm and dissection. At 3 days post-AngII infusion, suprarenal abdominal aorta presented significant volumetric dilatation and microstructural damage. Ex vivo assessment of vascular reactivity of the suprarenal dissection-prone aorta and its side branches, showed an endothelial and contractile dysfunctions that were severe in the suprarenal aorta, moderate distally, and absent in the side branches, mirroring the susceptibility to dissection of these different vascular segments. Early and specific morphofunctional changes of the suprarenal aorta may contribute to the regional onset of aortic aneurysm and dissection by exacerbating the biomechanical burden arising from its side branches

Dataset for "Co-Localization of Microstructural Damage and Excessive Mechanical Strain at Aortic Branches in Angiotensin-II Infused Mice"

This dataset contains geometries and simulation files for the manuscript "Co-Localization of Microstructural Damage and Excessive Mechanical Strain at Aortic Branches in Angiotensin-II Infused Mice", to be published in the journal "Biomechanics and Modeling in Mechanobiology". For each animal described in the study, the following data are uploaded: [mouse name]_Strain.vtp contains the Eulerian strain estimation for each abdominal aorta mapped back on the ex vivo undeformed configuration. [mouse name]_Scan.vtp is the abdominal aorta in the ex vivo undeformed configuration, as scanned using PCXTM imaging. [mouse name]_Exitron.vtp is the distribution of contrast agent infiltration along the aorta (can be superimposed to the corresponding ‘scan.vtp’ file), which serves a surrogate for vascular damage. The aortic partitioning described in the paper’s method section was performed on all of the above .vtp files for every animal. .vtp files can be visualized in the open-source Paraview or similar software, and used for centerline calculations using the open-source vmtk software