scholarly journals Pigmentation Affects Elastic Fiber Patterning and Biomechanical Behavior of the Murine Aortic Valve

2021 ◽  
Vol 8 ◽  
Author(s):  
Sana Nasim ◽  
Popular Pandey ◽  
Rosemeire M. Kanashiro-Takeuchi ◽  
Jin He ◽  
Joshua D. Hutcheson ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Elastic Fiber ◽  
Biomechanical Properties ◽  
Systemic Circulation ◽  
Elastic Fibers ◽  
Multiphoton Imaging ◽  
Force Microscopy ◽  
Biomechanical Behavior ◽  
Atomic Force ◽  
Fiber Organization

The aortic valve (AoV) maintains unidirectional blood distribution from the left ventricle of the heart to the aorta for systemic circulation. The AoV leaflets rely on a precise extracellular matrix microarchitecture of collagen, elastin, and proteoglycans for appropriate biomechanical performance. We have previously demonstrated a relationship between the presence of pigment in the mouse AoV with elastic fiber patterning using multiphoton imaging. Here, we extended those findings using wholemount confocal microscopy revealing that elastic fibers were diminished in the AoV of hypopigmented mice (KitWv and albino) and were disorganized in the AoV of K5-Edn3 transgenic hyperpigmented mice when compared to wild type C57BL/6J mice. We further used atomic force microscopy to measure stiffness differences in the wholemount AoV leaflets of mice with different levels of pigmentation. We show that AoV leaflets of K5-Edn3 had overall higher stiffness (4.42 ± 0.35 kPa) when compared to those from KitWv (2.22 ± 0.21 kPa), albino (2.45 ± 0.16 kPa), and C57BL/6J (3.0 ± 0.16 kPa) mice. Despite the striking elastic fiber phenotype and noted stiffness differences, adult mutant mice were found to have no overt cardiac differences as measured by echocardiography. Our results indicate that pigmentation, but not melanocytes, is required for proper elastic fiber organization in the mouse AoV and dictates its biomechanical properties.

scholarly journals The Effects of Elastic Fiber Protein Insufficiency and Treatment on the Modulus of Arterial Smooth Muscle Cells

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
M. Gabriela Espinosa ◽  
William S. Gardner ◽  
Lisa Bennett ◽  
Bradley A. Sather ◽  
Hiromi Yanagisawa ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Elastic Fiber ◽  
Muscle Cells ◽  
Elastic Fibers ◽  
Force Microscopy ◽  
Altered Gene Expression ◽  
Atomic Force ◽  
Fiber Protein ◽  
Altered Gene

Elastic fibers are critical for the mechanical function of the large arteries. Mechanical effects of elastic fiber protein deficiency have been investigated in whole arteries, but not in isolated smooth muscle cells (SMCs). The elastic moduli of SMCs from elastin (Eln-/-) and fibulin-4 (Fbln4-/-) knockout mice were measured using atomic force microscopy. Compared to control SMCs, the modulus of Eln-/- SMCs is reduced by 40%, but is unchanged in Fbln4-/- SMCs. The Eln-/- SMC modulus is rescued by soluble or α elastin treatment. Altered gene expression, specifically of calponin, suggests that SMC phenotypic modulation may be responsible for the modulus changes.

scholarly journals Biomechanics of Neutrophil Tethers

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 515
Author(s):  
Andrea Cugno ◽  
Alex Marki ◽  
Klaus Ley
Keyword(s):  
Cell Activation ◽  
Optical Trap ◽  
Biomechanical Properties ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Microfluidic Flow ◽  
Biomembrane Force Probe ◽  
Membrane Reservoir

Leukocytes, including neutrophils, which are propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 m long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.

Postnatal alterations in elastic fiber organization precede resistance artery narrowing in SHR

2006 ◽  
Vol 291 (2) ◽  
pp. H804-H812 ◽  
Author(s):  
José M. González ◽  
Ana M. Briones ◽  
Beatriz Somoza ◽  
Craig J. Daly ◽  
Elisabet Vila ◽  
...  
Keyword(s):  
Time Course ◽  
Elastic Fiber ◽  
Elastic Fibers ◽  
Early Event ◽  
Resistance Artery ◽  
Internal Elastic Lamina ◽  
Wall Stiffness ◽  
Fiber Deposition ◽  
Fiber Organization ◽  
Elastic Lamina

Resistance artery narrowing and stiffening are key elements in the pathogenesis of essential hypertension, but their origin is not completely understood. In mesenteric resistance arteries (MRA) from spontaneously hypertensive rats (SHR), we have shown that inward remodeling is associated with abnormal elastic fiber organization, leading to smaller fenestrae in the internal elastic lamina. Our current aim is to determine whether this alteration is an early event that precedes vessel narrowing, or if elastic fiber reorganization in SHR arteries occurs because of the remodeling process itself. Using MRA from 10-day-old, 30-day-old, and 6-mo-old SHR and normotensive Wistar Kyoto rats, we investigated the time course of the development of structural and mechanical alterations (pressure myography), elastic fiber organization (confocal microscopy), and amount of elastin (radioimmunoassay for desmosine) and collagen (picrosirius red). SHR MRA had an impairment of fenestrae enlargement during the first month of life. In 30-day-old SHR, smaller fenestrae and more packed elastic fibers in the internal elastic lamina were paralleled by increased wall stiffness. Collagen and elastin levels were unaltered at this age. MRA from 6-mo-old SHR also had smaller fenestrae and a denser network of adventitial elastic fibers, accompanied by increased collagen content and vessel narrowing. At this age, elastase digestion was less effective in SHR MRA, suggesting a lower susceptibility of elastic fibers to enzymatic degradation. These data suggest that abnormal elastic fiber deposition in SHR increases resistance artery stiffness at an early age, which might participate in vessel narrowing later in life.

DIRECTIONAL BIOMECHANICAL PROPERTIES OF PORCINE SKIN TISSUE

2014 ◽  
Vol 14 (05) ◽  
pp. 1450069 ◽  
Author(s):  
HSIAO-YING SHADOW HUANG ◽  
SIYAO HUANG ◽  
COLIN P. FRAZIER ◽  
PETER M. PRIM ◽  
OLA HARRYSSON
Keyword(s):  
Material Properties ◽  
Collagen Fiber ◽  
Biomechanical Properties ◽  
Skin Tissue ◽  
Elastic Fibers ◽  
Fiber Direction ◽  
Porcine Skin ◽  
Biomechanical Behavior ◽  
Tissue Anisotropy ◽  
Biaxial Mechanical Properties

Skin is a multilayered composite material and composed principally of the proteins collagen, elastic fibers and fibroblasts. The direction-dependent material properties of skin tissue is important for physiological functions like skin expansion. The current study has developed methods to characterize the directional biomechanical properties of porcine skin tissues as studies have shown that pigs represent a useful animal model due to similarities between porcine and human skin. It is observed that skin tissue has a nonlinear anisotropy biomechanical behavior, where the parameters of material modulus is 378 ± 160 kPa in the preferred-fiber direction and 65.96 ± 40.49 kPa in the cross-fiber direction when stretching above 30% strain equibiaxially. The result from the study provides methods of characterizing biaxial mechanical properties of skin tissue, as the collagen fiber direction appears to be one of the primary determinants of tissue anisotropy.

Study of elastic fiber organization by scanning force microscopy

1998 ◽  
Vol 17 (1) ◽  
pp. 75-83 ◽  
Author(s):  
I.Pasquali Ronchetti ◽  
A. Alessandrini ◽  
M. Baccarani Contri ◽  
C. Fornieri ◽  
G. Mori ◽  
...  
Keyword(s):  
Elastic Fiber ◽  
Scanning Force Microscopy ◽  
Force Microscopy ◽  
Scanning Force ◽  
Fiber Organization

scholarly journals The measurement of biomechanical properties of porcine articular cartilage using atomic force microscopy

2009 ◽  
Vol 72 (4/5) ◽  
pp. 251-259 ◽  
Author(s):  
Raphael Imer ◽  
Terunobu Akiyama ◽  
Nico F. de Rooij ◽  
Martin Stolz ◽  
Ueli Aebi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Articular Cartilage ◽  
Biomechanical Properties ◽  
Force Microscopy ◽  
Atomic Force

Die unterschiedliche Ausdehnung der Übergangszone in der Karotisgabel

VASA ◽  
2001 ◽  
Vol 30 (2) ◽  
pp. 101-106 ◽  
Author(s):  
J. Janzen ◽  
P. Lanzer ◽  
K. Rothenberger-Janzen ◽  
P.N. Vuong
Keyword(s):  
Carotid Artery ◽  
Transitional Zone ◽  
Biomechanical Properties ◽  
Elastic Fibers ◽  
Arterial Segment ◽  
Biomechanical Behavior ◽  
Atherosclerotic Lesions ◽  
The Media ◽  
Potential Factor ◽  
The Impact

Background: The goal of our study was to demonstrate the extension of the transitional zone (TZ) between elastic and muscular medial structure in carotid artery tripod. Patients and methods: A histologic study of 56 probes from 8 carotid artery tripods was performed. The probes were obtained from autopsies of 4 adults (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 different topographic sites. Results: At each level of the CCA (at 1 cm and 2 cm proximal to the bifurcation as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view field (200 ¥ magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arterial type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) muscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sections (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions have prevented the assessment of the arterial type in 4 probes (7.1%). The TZ in the medial structure of carotid artery tripods is exclusively localized in the ICA/ECA but not in the CCA. The ICA/ECA presented a TZ with a length up to 0.5 cm (4 probes; 25%), up to 1.5 cm (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%). Conclusions: In this study we confirmed that in the carotid artery tripod, a TZ – an arterial segment with transition from elastic to muscular type – does exist, involving a variable length. Furthermore studies on the impact of the biomechanical properties of the TZ as a potential factor in atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ should be considered prior to interventional procedures.

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