A strain energy function for arteries accounting for wall composition and structure

Zulliger, Martin A.

doi:10.1016/s0021-9290(03)00439-1

Cited by 70 publications

(134 citation statements)

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“…The straightening stretch is the stretch to be applied along the fiber to get it straightened. Therefore, P s distribution is of particular interest for developing structural models of arterial tissue, which take into account the waviness of fibers (Zulliger et al 2004;Cacho et al 2007). These studies are mainly influenced by an earlier framework proposed by Lanir (1983).…”

Section: Analysis Of Collagen Fiber Wavinessmentioning

confidence: 99%

Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy

Rezakhaniha

Agianniotis

Schrauwen

et al. 2011

Biomech Model Mechanobiol

893

786

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Mechanical properties of the adventitia are largely determined by the organization of collagen fibers. Measurements on the waviness and orientation of collagen, particularly at the zero-stress state, are necessary to relate the structural organization of collagen to the mechanical response of the adventitia. Using the fluorescence collagen marker CNA38-OG488 and confocal laser scanning microscopy, we imaged collagen fibers in the adventitia of rabbit common carotid arteries ex vivo. The arteries were cut open along their longitudinal axes to get the zero-stress state. We used semi-manual and automatic techniques to measure parameters related to the waviness and orientation of fibers. Our results showed that the straightness parameter (defined as the ratio between the distances of endpoints of a fiber to its length) was distributed with a beta distribution (mean value 0.72, variance 0.028) and did not depend on the mean angle orientation of fibers. Local angular density distributions revealed four axially symmetric families of fibers with mean directions of 0 • , 90 • , 43 • and −43 • , with respect to the axial direction of the artery, and corresponding circular standard deviations of 40 • , 47 • , 37 • and 37 • . The distribution of local orientations was shifted to the circumferential direction when measured in arteries at the zero-load state (intact), as compared to arteries at the zero-stress state (cutopen). Information on collagen fiber waviness and orientation, such as obtained in this study, could be used to develop structural models of the adventitia, providing better means for analyzing and understanding the mechanical properties of vascular wall.

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Section: Analysis Of Collagen Fiber Wavinessmentioning

confidence: 99%

Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy

Rezakhaniha

Agianniotis

Schrauwen

et al. 2011

Biomech Model Mechanobiol

893

786

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“…Most importantly, structural SEFs allocate macroscopic stress to different micro-structural components, and are able to link the macroscopic loading to potential cellular responses. Structural SEFs for the vessel wall are based on fiber-reinforced composite concepts, which assume straight and parallel-aligned [16,33,40], straight and orientation-dispersed [1,13], undulated and parallelaligned [39,40], or undulated and orientation-dispersed [19,23] (families of) fibers. 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.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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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

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“…Numerous models have been developed for arterial microcirculatory networks and the roles of myogenic, shear, and metabolic responses in the autoregulation of blood flow. [12][13][14] However, none of these models have been adapted to describe the regulation of lymph flow.…”

Section: Introductionmentioning

confidence: 99%

Passive Pressure–Diameter Relationship and Structural Composition of Rat Mesenteric Lymphangions

Rahbar

Weimer

Gibbs

et al. 2012

Lymphatic Research and Biology

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Background: Lymph flow depends on both the rate of lymph production by tissues and the extent of passive and active pumping. Here we aim to characterize the passive mechanical properties of a lymphangion in both midlymphangion and valve segments to assess regional differences along a lymphangion, as well as evaluating its structural composition. Methods and Results: Mesenteric lymphatic vessels were isolated and cannulated in a microchamber for pressure-diameter (P-D) testing. Vessels were inflated from 0 to 20 cmH 2 O at a rate of 4 cmH 2 O/min, and vessel diameter was continuously tracked, using an inverted microscope, video camera, and custom LabVIEW program, at both mid-lymphangion and valve segments. Isolated lymphatic vessels were also pressure-fixed at 2 and 7 cmH 2 O and imaged using a nonlinear optical microscope (NLOM) to obtain collagen and elastin structural information. We observed a highly nonlinear P-D response at low pressures (3-5 cmH 2 O), which was modeled using a three-parameter constitutive equation. No significant difference in the passive P-D response was observed between mid-lymphangion and valve regions. NLOM imaging revealed an inner elastin layer and outer collagen layer at all locations. Lymphatic valve leaflets were predominantly elastin with thick axially oriented collagen bands at the insertion points. Conclusions: We observed a highly nonlinear P-D response at low pressures (3-5 cmH 2 O) and developed the first constitutive equation to describe the passive P-D response for a lymphangion. The passive P-D response did not vary among regions, in agreement with the composition of elastin and collagen in the lymphatic wall.

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A strain energy function for arteries accounting for wall composition and structure

Cited by 70 publications

References 0 publications

Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy

Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy

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

Passive Pressure–Diameter Relationship and Structural Composition of Rat Mesenteric Lymphangions

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