title: Progressive alterations in microstructural organization and biomechanical response in the ApoE mouse model of aneurysm.
abstract: AAA is a complex disease that leads to a localized dilation of the infrarenal aorta that develops over years. Longitudinal information in humans has been difficult to obtain for this disease, therefore mouse models have become increasingly used to study the development of AAAs. The objective of this study was to determine any changes that occur in the biomechanical response and fiber microstructure in the ApoE(-/-) AngII mouse model of aneurysm during disease progression. Adult ApoE(-/-) AngII infused mice along with wild-type controls were taken at 14 and 28 d. Aortas were excised and tested simultaneously for biaxial mechanical response and ECM organization. Data sets were fit to a Fung-type constitutive model to give peak strains and stiffness values. Images from two photon microscopy were quantified in order to assess the preferred fiber alignment and degree of fiber orientation. Biomechanical results found significant differences that were present at 14 d had returned to normal by 28 d along with significant changes in fiber orientation and dispersion indicating remodeling occurring within the aneurysmal wall. This return of some of the normal biomechanical function, in addition the continuing changes that occur in the microstructure suggest a restorative response that occurs in the ApoE(-/-) AngII infused model after the initial aneurysm formation.
authors.affiliation: Graduate Interdisciplinary Program of Biomedical Engineering; University of Arizona; Tucson, AZ USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Haskett
authors.affiliation: Developmental Biology and Neonatal Medicine Program, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN USA.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Azhar
authors.affiliation: Graduate Interdisciplinary Program of Biomedical Engineering; University of Arizona; Tucson, AZ USA; BIO5 Institute; University of Arizona; Tucson, AZ USA; Department of Biomedical Engineering; University of Arizona; Tucson, AZ USA.
authors.forename: Urs
authors.initials: U
authors.lastname: Utzinger
authors.affiliation: Graduate Interdisciplinary Program of Biomedical Engineering; University of Arizona; Tucson, AZ USA; BIO5 Institute; University of Arizona; Tucson, AZ USA; Department of Biomedical Engineering; University of Arizona; Tucson, AZ USA; Department of Aerospace and Mechanical Engineering; University of Arizona; Tucson, AZ USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Vande Geest
mesh_terms: D000804:Angiotensin II / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001011:Aorta / Q000503:physiopathology* / Q000648:ultrastructure; D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology*; D001057:Apolipoproteins E / Q000235:genetics* / Q000378:metabolism; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000473:pathology / Q000648:ultrastructure; D055786:Gene Knockout Techniques; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D036641:Microscopy, Fluorescence, Multiphoton
chemical_list: D001057:Apolipoproteins E; D000804:Angiotensin II
keywords: AAA; AngII; ApoE; aneurysm; mechanical; microstructure; mouse model; two-photon