A structural finite element model for lamellar unit of aortic media indicates heterogeneous stress field after collagen recruitment
| Autor: | Thomas G. Gleason, Siladitya Pal, Spandan Maiti, Ronald N. Fortunato, James Thunes, David A. Vorp, Julie A. Phillippi |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Materials science Finite Element Analysis 0206 medical engineering Biomedical Engineering Biophysics Aorta Thoracic 02 engineering and technology Matrix (biology) Article Extracellular matrix 03 medical and health sciences Bicuspid aortic valve medicine.artery Collagen network medicine Humans Orthopedics and Sports Medicine Fiber Stress concentration Aorta Aortic Aneurysm Thoracic Rehabilitation medicine.disease 020601 biomedical engineering Extracellular Matrix Stress field 030104 developmental biology Collagen Stress Mechanical Tunica Media Biomedical engineering |
| Zdroj: | Journal of Biomechanics. 49:1562-1569 |
| ISSN: | 0021-9290 |
| Popis: | Incorporation of collagen structural information into the study of biomechanical behavior of ascending thoracic aortic (ATA) wall tissue should provide better insight into the pathophysiology of ATA. Structurally motivated constitutive models that include fiber dispersion and recruitment can successfully capture overall mechanical response of the arterial wall tissue. However, these models cannot examine local microarchitectural features of the collagen network, such as the effect of fiber disruptions and interaction between fibrous and non-fibrous components, which may influence emergent biomechanical properties of the tissue. Motivated by this need, we developed a finite element based three-dimensional structural model of the lamellar units of the ATA media that directly incorporates the collagen fiber microarchitecture. The fiber architecture was computer generated utilizing network features, namely fiber orientation distribution, intersection density and areal concentration, obtained from image analysis of multiphoton microscopy images taken from human aneurysmal ascending thoracic aortic media specimens with bicuspid aortic valve (BAV) phenotype. Our model reproduces the typical J-shaped constitutive response of the aortic wall tissue. We found that the stress state in the non-fibrous matrix was homogeneous until the collagen fibers were recruited, but became highly heterogeneous after that event. The degree of heterogeneity was dependent upon local network architecture with high stresses observed near disrupted fibers. The magnitude of non-fibrous matrix stress at higher stretch levels was negatively correlated with local fiber density. The localized stress concentrations, elucidated by this model, may be a factor in the degenerative changes in aneurysmal ATA tissue. |
| Databáze: | OpenAIRE |
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