Spatial orientation of collagen fibers in the abdominal aortic aneurysm’s wall and its relation to wall mechanics

Gasser, Thomas C.; Gallinetti, Sara; Xing, Xin; Forsell, Caroline; Swedenborg, Jesper; Roy, Joy

doi:10.1016/j.actbio.2012.04.044

Cited by 137 publications

(104 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The variableρ has been introduced to account for the variability of the collagen fiber distribution, as proposed by (Gasser et al, 2006;Alastrue et al, 2010) in the context of biological tissues. A statistical distribution function characterizes the probability of finding a collagen fibril in a given direction as has been experimentally reported for arterial tissue (Schriefl et al, 2012;Gasser et al, 2012). Here, we adopt a Bingham distribution (Bingham, 1974) to account for the distribution of the individual fibrils, which is given bŷ…”

Section: Collagen Behaviormentioning

confidence: 99%

Mathematical modeling of collagen turnover in biological tissue

et al. 2012

View full text Add to dashboard Cite

We present a theoretical and computational model for collagen turnover in soft biological tissues. Driven by alterations in the mechanical environment, collagen fiber bundles may undergo important chronic changes, characterized primarily by alterations in collagen synthesis and degradation rates. In particular, hypertension triggers an increase in tropocollagen synthesis and a decrease in collagen degradation, which lead to the well-documented overall increase in collagen content. These changes are the result of a cascade of events, initiated mainly by the endothelial and smooth muscle cells. Here, we represent these events collectively in terms of two internal variables, the concentration of growth factor TGF-β and tissue inhibitors of metalloproteinases TIMP. While the upregulation of the former increases the collagen density, the upregulation of the latter increases the collagen density through decreasing matrix metalloproteinase MMP. We establish a mathematical theory for mechanically-induced collagen turnover and introduce a computational algorithm for its robust and efficient solution. We demonstrate that our model can accurately predict the experimentally observed collagen increase in response to hypertension reported in literature. Ultimately, the model can serve as a valuable tool to predict the chronic adaptation of collagen content to restore the homeostatic equilibrium state in vessels with arbitrary micro-structure and geometry.

show abstract

Section: Collagen Behaviormentioning

confidence: 99%

Mathematical modeling of collagen turnover in biological tissue

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Gasser et al [81] calculated the distribution of collagen fibre orientations within the anterior wall of IRAA aneurysm. It was found that, in the anterior wall of IRAA aneurysm, the collagen fibre orientation was widely dispersed, with the dispersion being higher in the tangential than in the cross-sectional plane.…”

Section: Effects Of Locationmentioning

confidence: 99%

Elastin and collagen fibre microstructure of the human aorta in ageing and disease: a review

Tsamis

Krawiec

Vorp

2013

J. R. Soc. Interface.

405

300

View full text Add to dashboard Cite

Aortic disease is a significant cause of death in developed countries. The most common forms of aortic disease are aneurysm, dissection, atherosclerotic occlusion and ageing-induced stiffening. The microstructure of the aortic tissue has been studied with great interest, because alteration of the quantity and/or architecture of the connective fibres (elastin and collagen) within the aortic wall, which directly imparts elasticity and strength, can lead to the mechanical and functional changes associated with these conditions. This review article summarizes the state of the art with respect to characterization of connective fibre microstructure in the wall of the human aorta in ageing and disease, with emphasis on the ascending thoracic aorta and abdominal aorta where the most common forms of aortic disease tend to occur.

show abstract

“…[12,31]. Then the segments were further dehydrated, embedded in paraffin, and tangentially sectioned at 7.0 [µm] thickness.…”

Section: Mechanical Inflation Testingmentioning

confidence: 99%

“…Despite the fact that considerable work has been dedicated to develop and numerically implement structural SEFs, only very few studies consistently validated structural SEFs, i.e. by treating histological and mechanical input information strictly separately [12,15,26,37]. In contrast, most studies estimated both histological and mechanical model parameters from mechanical experimental data, i.e.…”

Section: Introductionmentioning

confidence: 99%

Microstructural quantification of collagen fiber orientations and its integration in constitutive modeling of the porcine carotid artery

et al. 2016

View full text Add to dashboard Cite

Background Mechanical characteristics of vascular tissue may play a role in different arterial pathologies, which, amongst others, requires robust constitutive descriptions to capture the vessel wall’s anisotropic and non-linear properties.Specifically, the complex 3D network of collagen and its interaction with other structural elements has a dominating effect of arterial properties at higher stress levels.The aim of this study is to collect quantitative collagen organization as well as mechanical properties to facilitate structural constitutive models for the porcine carotid artery.This helps the understanding of the mechanics of swine carotid arteries, being a standard in clinical hypothesis testing, in endovascular preclinical trials for example. Method Porcine common carotid arteries (n = 10) were harvested and used to (i) characterize the collagen fiber organization with polarized light microscopy, and (ii) the biaxial mechanical properties by inflation testing.The collagen organization was quantified by the Bingham orientation density function (ODF), which in turn was integrated in a structural constitutive model of the vessel wall.A one-layered and thick-walled model was used to estimate mechanical constitutive parameters by least-square fitting the recorded in vitro inflation test results.Finally, uniaxial data published elsewhere were used to validate the mean collagen organization described by the Bingham ODF. Results Thick collagen fibers, i.e.the most mechanically relevant structure, in the common carotid artery are dispersed around the circumferential direction.In addition, almost all samples showed two distinct families of collagen fibers at different elevation, but not azimuthal, angles.Collagen fiber organization could be accurately represented by the Bingham ODF (¿1,2,3=[13.5,0.0,25.2] and ¿1,2,3=[14.7,0.0,26.6]; average error of about 5%), and their integration into a structural constitutive model captured the inflation characteristics of individual carotid artery samples.Specifically, only four mechanical parameters were required to reasonably (average error from 14% to 38%) cover the experimental data over a wide range of axial and circumferential stretches.However, it was critical to account for fibrilar links between thick collagen fibers.Finally, the mean Bingham ODF provide also good approximation to uniaxial experimental data. Conclusions The applied structural constitutive model, based on individually measured collagen orientation densities, was able to capture the biaxial properties of the common carotid artery. Since the model required coupling amongst thick collagen fibers, the collagen fiber orientations measured from polarized light microscopy, alone, seem to be insufficient structural information. Alternatively, a larger dispersion of collagen fiber orientations, that is likely to arise from analyzing larger wall sections, could have had a similar effect, i.e. could have avoided coupling amongst thick collagen fibers.Peer ReviewedPostprint (author's final draft

show abstract

Spatial orientation of collagen fibers in the abdominal aortic aneurysm’s wall and its relation to wall mechanics

Cited by 137 publications

References 48 publications

Mathematical modeling of collagen turnover in biological tissue

Mathematical modeling of collagen turnover in biological tissue

Elastin and collagen fibre microstructure of the human aorta in ageing and disease: a review

Microstructural quantification of collagen fiber orientations and its integration in constitutive modeling of the porcine carotid artery

Contact Info

Product

Resources

About