Structurally Motivated Models of the Arterial Wall Tissue

2013 ◽  
Vol 05 (04) ◽  
pp. 1330002 ◽  
Author(s):  
Hadi Taghizadeh ◽  
Mohammad Tafazzoli Shadpour

Mechanical characteristics of soft biological tissues mostly depend on their hierarchy at different scales from nano- to macro-structure. It is shown that arterial wall tissue is highly sensitive to its mechanical environment and any alteration in mechanical factors such as blood pressure, triggers physio- pathological processes within arterial wall. Quantification of these mechanical properties will provide us with deeper insights of ongoing biological events. In this context, mechanical contributions of wall constituents in health and diseases are of growing interest. Hence, this review is concerned with mechanical models of arterial wall tissue with a focus on microstructurally motivated representations.

Author(s):  
Arjen van der Horst ◽  
Chantal N. van den Broek ◽  
Marcel C. M. Rutten ◽  
Frans N. van de Vosse

Mechanical characterization of the coronary arterial wall is important for several reasons. Mechanical factors play an important role in the development of atherosclerosis [1]. Atherosclerotic coronary arteries may be treated mechanically with interventions like PTCA and stent implantation, 1265000 PTCA procedures were performed in the United States in 2005 [2]. Furthermore, knowledge of the mechanical properties of the arterial wall is important for modeling of the coronary circulation and explaining its hemodynamics.


Author(s):  
Kristy Tan ◽  
Shaokoon Cheng ◽  
Lynne E. Bilston

The mechanical properties of soft biological tissues have been widely investigated over the past five decades [1–5]. Reported measurements of soft biological tissues such as the brain, spinal cord, liver and muscle vary by orders of magnitude, depending on the sample preparation, anisotropy and loading regime. Knowing the accurate mechanical properties of biological tissues is important for many applications, for example car crash testing and simulations require accurate information on how different parts of the body deform due to a combination of loads. Deformation of tissues around prosthetics and artificial limbs are critical in understanding load transfer at interfaces with the body. The recent use of Magnetic Resonance Elastography (MRE) in diagnostic imaging has resulted in a surge of interest in accurate measurements of mechanical properties of tissues [6].


2021 ◽  
Vol 18 (182) ◽  
pp. 20210411
Author(s):  
Gerhard A. Holzapfel ◽  
Kevin Linka ◽  
Selda Sherifova ◽  
Christian J. Cyron

The constitutive modelling of soft biological tissues has rapidly gained attention over the last 20 years. Current constitutive models can describe the mechanical properties of arterial tissue. Predicting these properties from microstructural information, however, remains an elusive goal. To address this challenge, we are introducing a novel hybrid modelling framework that combines advanced theoretical concepts with deep learning. It uses data from mechanical tests, histological analysis and images from second-harmonic generation. In this first proof of concept study, our hybrid modelling framework is trained with data from 27 tissue samples only. Even such a small amount of data is sufficient to be able to predict the stress–stretch curves of tissue samples with a median coefficient of determination of R 2 = 0.97 from microstructural information, as long as one limits the scope to tissue samples whose mechanical properties remain in the range commonly encountered. This finding suggests that deep learning could have a transformative impact on the way we model the constitutive properties of soft biological tissues.


Author(s):  
Robert T. Johnson ◽  
Reesha Solanki ◽  
Derek T. Warren

AbstractArterial smooth muscle cells (ASMCs), the predominant cell type within the arterial wall, detect and respond to external mechanical forces. These forces can be derived from blood flow (i.e. pressure and stretch) or from the supporting extracellular matrix (i.e. stiffness and topography). The healthy arterial wall is elastic, allowing the artery to change shape in response to changes in blood pressure, a property known as arterial compliance. As we age, the mechanical forces applied to ASMCs change; blood pressure and arterial wall rigidity increase and result in a reduction in arterial compliance. These changes in mechanical environment enhance ASMC contractility and promote disease-associated changes in ASMC phenotype. For mechanical stimuli to programme ASMCs, forces must influence the cell’s load-bearing apparatus, the cytoskeleton. Comprised of an interconnected network of actin filaments, microtubules and intermediate filaments, each cytoskeletal component has distinct mechanical properties that enable ASMCs to respond to changes within the mechanical environment whilst maintaining cell integrity. In this review, we discuss how mechanically driven cytoskeletal reorganisation programmes ASMC function and phenotypic switching.


Author(s):  
Daniela Valdez-Jasso ◽  
Mansoor A. Haider ◽  
Stephen L. Campbell ◽  
Daniel Bia ◽  
Yanina Zocalo ◽  
...  

Generation of a complete map of arterial wall mechanical properties can improve treatment of cardiovascular diseases via contributions to design of patient specific vascular substitutes used to alleviate atherosclerosis and stenoses, which are predominant in arterial pathways (i.e., abdominal aorta, carotids, or femoral arteries). Clinically useful estimation of arterial properties from patient data requires both efficient algorithms and models that are both complex enough to capture clinically important properties and simple enough to allow rapid computation. In this study, we used mechanical models accounting for both elastic and viscoelastic wall deformation to analyze how vessel properties and associated model parameters vary with artery type. It is known that for the aorta wall, deformation is dominated by nonlinear elastic dynamics, while for the smaller vessels (e.g. the carotid artery) deformation is dominated by viscoelastic responses. The latter is correlated with composition of the vessels; the aorta contains significantly less smooth muscle cells (∼40%) than the carotid artery (∼60%), and has significantly more elastin (see Fig 1).


2019 ◽  
Vol 70 (10) ◽  
pp. 3469-3472

Weldability involves two aspects: welding behavior of components and safety in operation. The two aspects will be reduced to the mechanical characteristics of the elements and to the chemical composition. In the case of steel reinforcing rebar’s, it is reduces to the percentage of Cech(carbon equivalent) and to the mechanical characteristics: the yielding limit, the ultimate limit, and the elongations which after that represent the ductility class in which the re-bars is framed. The paper will present some types of steel reinforcing rebar’s with its mechanical characteristics and the welding behavior of those elements. In the current work, process-related behavior of welded reinforcement, joint local and global mechanical properties, and their correlation with behavior of normal reinforcement and also the mechanical performance resulted in this type of joints. Keywords: welding behavior, ultimate limit, reinforcing rebar’s


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1656
Author(s):  
Carla Huerta-López ◽  
Jorge Alegre-Cebollada

Biomaterials are dynamic tools with many applications: from the primitive use of bone and wood in the replacement of lost limbs and body parts, to the refined involvement of smart and responsive biomaterials in modern medicine and biomedical sciences. Hydrogels constitute a subtype of biomaterials built from water-swollen polymer networks. Their large water content and soft mechanical properties are highly similar to most biological tissues, making them ideal for tissue engineering and biomedical applications. The mechanical properties of hydrogels and their modulation have attracted a lot of attention from the field of mechanobiology. Protein-based hydrogels are becoming increasingly attractive due to their endless design options and array of functionalities, as well as their responsiveness to stimuli. Furthermore, just like the extracellular matrix, they are inherently viscoelastic in part due to mechanical unfolding/refolding transitions of folded protein domains. This review summarizes different natural and engineered protein hydrogels focusing on different strategies followed to modulate their mechanical properties. Applications of mechanically tunable protein-based hydrogels in drug delivery, tissue engineering and mechanobiology are discussed.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mary Beth Wandel ◽  
Craig A. Bell ◽  
Jiayi Yu ◽  
Maria C. Arno ◽  
Nathan Z. Dreger ◽  
...  

AbstractComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical, and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.


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