Effect of Hypertension on Elasticity and Geometry of Aortic Tissue From Dogs

Vaishnav, Ramesh N.; Vossoughi, Jafar; Patel, Dali J.; Cothran, Laval N.; Coleman, Bernell; Ison-Franklin, Eleanor L.

doi:10.1115/1.2891128

Cited by 74 publications

(36 citation statements)

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“…The changes in unloaded length have been reported with decreasing longitudinal retractions in hypertensive canine aorta (Vaishnav et al 1990). Our model predicts an increased unloaded length and inner radius with time (figure 16), which is qualitatively consistent with this observation.…”

Section: Altered Pressuresupporting

confidence: 88%

Complementary vasoactivity and matrix remodelling in arterial adaptations to altered flow and pressure

Valentín

Cardamone

Baek

et al. 2008

J. R. Soc. Interface.

155

230

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Arteries exhibit a remarkable ability to adapt to sustained alterations in biomechanical loading, probably via mechanisms that are similarly involved in many arterial pathologies and responses to treatment. Of particular note, diverse data suggest that cell and matrix turnover within vasoaltered states enables arteries to adapt to sustained changes in blood flow and pressure. The goal herein is to show explicitly how altered smooth muscle contractility and matrix growth and remodelling work together to adapt the geometry, structure, stiffness and function of a representative basilar artery. Towards this end, we employ a continuum theory of constrained mixtures to model evolving changes in the wall, which depend on both wall shear stress-induced changes in vasoactive molecules (which alter smooth muscle proliferation and synthesis of matrix) and intramural stress-induced changes in growth factors (which alter cell and matrix turnover). Simulations show, for example, that such considerations help explain the different rates of experimentally observed adaptations to increased versus decreased flows as well as differences in rates of change in response to increased flows or pressures.

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Section: Altered Pressuresupporting

confidence: 88%

Complementary vasoactivity and matrix remodelling in arterial adaptations to altered flow and pressure

Valentín

Cardamone

Baek

et al. 2008

J. R. Soc. Interface.

155

230

View full text Add to dashboard Cite

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“…4.20). These results indicate that not only circumferential stress but also stiffness is restored [40,41], but restoration of the elastic modulus takes longer time. Pressure-fixed in each in vivo condition and stained with Azan-Mallory.…”

Section: Long-term Response To Pressure Increasementioning

confidence: 81%

“…It is clear that the wall thickness increases markedly in response to blood pressure increase. This wall thickening is believed to be an adaptive response to maintain the circumferential wall stress at a constant level [37][38][39][40]. Relationships between the systolic blood pressure and circumferential stress at this pressure are shown in Fig.…”

Section: Long-term Response To Pressure Increasementioning

confidence: 96%

Biomechanics of Blood Vessels: Structure, Mechanics, and Adaptation

Matsumotο

Sugita

Yaguchi

2015

Springer Series in Biomaterials Science and Engineering

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Basics and recent advances in blood vessel wall biomechanics are overviewed. The structure of blood vessel walls is first introduced with special reference to heterogeneity in the mechanical properties of artery walls at a microscopic level. Then basic characteristics of the mechanical properties of blood vessel walls are explained from the viewpoints of mechanical parameters used in clinical investigations, elastic and viscoelastic analysis, and effects of smooth muscle contraction. As examples of mechanical analysis of blood vessel walls, stress and strain analyses of artery walls as thin-and thick-walled cylinders, analyses considering residual stress and microscopic heterogeneity, are introduced. One of the most important topics in the blood vessel mechanics, mechanical responses and adaptations of blood vessel walls, is then discussed from the viewpoints of long-and shortterm responses of artery walls to increases in blood pressure or flow. And finally, the importance of studying microscopic mechanical environment to elucidate these mechanical adaptations is pointed out.

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“…The second equation reveals the importance of the thickness:lumen ratio (h/a), noting that h is total, not intimal-medial, thickness, and the third equation shows the importance of wall cross-sectional area, which is often reported with regard to "eutrophic" versus "hypertropic" remodeling. Although the importance of axial stress and stretch in hypertension was recognized years ago, 7 it has received little attention because of the inability to infer values in vivo. Large arteries appear to maintain these stresses near homeostatic values (eg, on the order of 1.5 Pa for w and 100 kPa for both and z in specific arteries, 2-4 where 1 kPaϭ7.5 mm Hg).…”

Section: Biomechanical Consequences Of Perturbed Flow and Pressurementioning

confidence: 99%

“…The latter may occur because of a net increase in the collagen:elastin ratio that unloads the prestretched elastin, 6 which may be related to the aforementioned observation that axial prestretch decreases in hypertension. 7 Potential implications of this to overall (biaxial) mechanical homeostasis remain unknown, however.…”

Section: Vasoaltered Statesmentioning

confidence: 99%

Mechanisms of Arterial Remodeling in Hypertension

2008

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Diverse data collected over the past 4 decades suggest the existence of a mechanical homeostasis across multiple length and time scales in the vasculature. For example, 1 stress fibers within endothelial and vascular smooth muscle cells appear to disassemble and then reassemble in a mechanically preferred manner when perturbed from a normal value of mechanical stress or strain; focal adhesions in smooth muscle cells and fibroblasts tend to increase in area in response to local increases in mechanical loading so as to maintain the stress constant at a preferred value; fibroblasts tend to increase the tractions that they exert on the extracellular matrix when external loads are decreased from a preferred value, thus suggesting an attempt to enforce a "tensional homeostasis"; vascular smooth muscle cells tend to relengthen to their normal, preferred values when an arteriole is forced into a vasoconstricted state for an extended period; and arteries tend to decrease in caliber in response to sustained decreases in flow-induced wall shear stress, to increase in thickness in response to sustained increases in pressureinduced circumferential stress, and to lengthen in response to extension-induced increases in axial stress. Although changes in the cytoskeleton and integrins occur within minutes, changes at the cell-cell and cell-matrix levels occur over hours, and those at the vessel level occur over days to weeks or months. Hence, despite marked differences in length scales (dimensions from nanometers to centimeters) and time scales (durations from minutes to months), mechanobiological control mechanisms in the vasculature tend to restore values of stress or strain toward preferred (homeostatic) values in response to diverse perturbations from normal. 2-5 Biomechanics and mechanobiology thus play key roles in vascular development, tissue maintenance in maturity, normal adaptations, aging, disease progression, and responses to injury or clinical interventions.A current challenge in hypertension research is to understand how mechanobiological mechanisms at molecular and cellular levels (eg, altered turnover of collagen) manifest at tissue and organ levels and, conversely, how mechanical loads at tissue and organ levels (eg, increased pulse pressure) are sensed by molecular structures and result in altered gene expression. To gain increased understanding, we can exploit lessons learned from all areas of vascular research, because it appears that the same fundamental cell-mediated mechanisms govern diverse cases of vascular growth (ie, change in mass) and remodeling (ie, change in structure) via the reorganization and/or turnover of cells and extracellular matrix in evolving biomechanical states. 1

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Effect of Hypertension on Elasticity and Geometry of Aortic Tissue From Dogs

Cited by 74 publications

References 0 publications

Complementary vasoactivity and matrix remodelling in arterial adaptations to altered flow and pressure

Complementary vasoactivity and matrix remodelling in arterial adaptations to altered flow and pressure

Biomechanics of Blood Vessels: Structure, Mechanics, and Adaptation

Mechanisms of Arterial Remodeling in Hypertension

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