title: Effect of aneurysm on biomechanical properties of "radially-oriented" collagen fibers in human ascending thoracic aortic media.
abstract: We recently reported a mechanistic model to link micro-architectural information to the delamination strength (Sd) of human ascending thoracic aorta (ATA). That analysis demonstrated that the number density (N) and failure energy (Uf) of the radially-oriented collagen fibers contribute to the Sd of both aneurysmal (ATAA) and non-aneurysmal (CTRL-ATA) aortic tissue. Among the set of ATAA samples, we studied specimens from patients displaying bicuspid (BAV) and tricuspid aortic valve (TAV) morphologic phenotypes. Results from our prior work were based on the assumption that the Uf was independent of dissection direction. In the current study, we excluded that assumption and hypothesized that Uf correlates with the Sd of ATAA. To test the hypothesis, we used previously-reported experimentally-determined Sd measurements and N of radially-oriented collagen fibers as input in our validated mechanistic model to calculate Uf for BAV-ATAA, TAV-ATAA and CTRL-ATA tissue specimens. The results of our analysis revealed that Uf is significantly lower for both BAV-ATAA and TAV-ATAA compared to CTRL-ATA cases, and does not differ between BAV-ATAA and TAV-ATAA. Furthermore, we found that Uf is consistent between circumferential-radial and longitudinal-radial planes in either of BAV-ATAA, TAV-ATAA or CTRL-ATA specimens. These findings employ a novel mechanistic model to increase our understanding of the putative interrelationship between biomechanical properties, extracellular matrix biology, and failure energy of aortic dissection.
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Alkiviadis
authors.initials: A
authors.lastname: Tsamis
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Siladitya
authors.initials: S
authors.lastname: Pal
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Phillippi
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Gleason
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States. Electronic address: spm54@pitt.edu.
authors.forename: Spandan
authors.initials: S
authors.lastname: Maiti
authors.affiliation: Departments of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: David A
authors.initials: DA
authors.lastname: Vorp
mesh_terms: D000784:Aortic Dissection; D001011:Aorta / Q000737:chemistry; D001013:Aorta, Thoracic / Q000503:physiopathology*; D001014:Aortic Aneurysm; D017545:Aortic Aneurysm, Thoracic / Q000503:physiopathology*; D001021:Aortic Valve; D001703:Biophysics; D003094:Collagen / Q000032:analysis / Q000502:physiology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D010641:Phenotype; D017540:Tunica Media / Q000737:chemistry / Q000503:physiopathology*
chemical_list: D003094:Collagen
keywords: Dissection; Fiber bridge failure energy; Human ascending thoracic aortic aneurysm; Micro-architecture; Multi-photon microscopy; Radially-oriented collagen