Murine ultrasound imaging for circumferential strain analyses in the angiotensin II abdominal aortic aneurysm model.
J Vasc Surg
; 56(2): 462-9, 2012 Aug.
Article
em En
| MEDLINE
| ID: mdl-22503226
ABSTRACT
OBJECTIVE:
The underlying causes of abdominal aortic aneurysms (AAAs) remain obscure, although research tools such as the angiotensin II (Ang II) apolipoprotein E-deficient (apoE(-/-)) mouse model have aided investigations. Longitudinal imaging and determination of biomechanical forces in this small-scale model have been difficult. We hypothesized that high-frequency ultrasound biomicroscopy combined with speckle-tracking analytical strategies can be used to define the role of circumferential mechanical strain in AAA formation in the Ang II/apoE(-/-) mouse model of AAAs. We simultaneously examined dietary perturbations that might impact the biomechanical properties of the aortic wall, hypothesizing that the generalized inflammatory phenotype associated with diet-induced obesity would be associated with accelerated loss of circumferential strain and aneurysmal aortic degeneration.METHODS:
Receiving either a 60 kcal% fat Western diet or standard 10 kcal% fat normal chow, Ang II-treated apoE(-/-) mice (n = 34) underwent sequential aortic duplex ultrasound scan imaging (Vevo 2100 System; VisualSonics, Toronto, Ontario, Canada) of their entire aorta. Circumferential strains were calculated using speckle-tracking algorithms and a custom MatLab analysis.RESULTS:
Decreased strains in all aortic locations after just 3 days of Ang II treatment were observed, and this effect progressed during the 4-week observation period. Anatomic segments along the aorta impacted wall strain (baseline highest in ascending aorta; P < .05), whereas diet did not. At 2 and 4 weeks, there was the largest progressive decrease in strain in the paravisceral/supraceliac aorta (P < .05), which was the segment most likely to be involved in aneurysm formation in this model.CONCLUSIONS:
In the Ang II/apoE(-/-) aneurysm model, the aorta significantly stiffens (with decreased strain) shortly after Ang II infusion, and this progressively continues through the next 4 weeks. High-fat feeding did not have an impact on wall strain. Delineation of biomechanical factors and AAA morphology via duplex scan and speckle-tracking algorithms in mouse models should accelerate insights into human AAAs.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Aneurisma da Aorta Abdominal
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Ultrassonografia Doppler Dupla
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Microscopia Acústica
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Modelos Animais de Doenças
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article