scholarly journals Corrigendum: Postnatal and Adult Aortic Heart Valves Have Distinctive Transcriptional Profiles Associated With Valve Tissue Growth and Maintenance Respectively

2019 ◽  
Vol 6 ◽  
Author(s):  
Emily Nordquist ◽  
Stephanie LaHaye ◽  
Casey Nagel ◽  
Joy Lincoln
Keyword(s):  
Heart Valves ◽  
Tissue Growth ◽  
Transcriptional Profiles ◽  
Valve Tissue

Specimen Dynamics and Subsequent Implications in Heart Valve Tissue Engineering Studies

2011 ◽  
Author(s):  
M. Salinas ◽  
R. Lange ◽  
S. Ramaswamy
Keyword(s):  
Tissue Engineering ◽  
Heart Valve ◽  
Heart Valves ◽  
Fluid Dynamic ◽  
Critical Role ◽  
Tissue Growth ◽  
Valve Tissue ◽  
Heart Valve Tissue ◽  
Heart Valve Tissue Engineering ◽  
Stress States

In heart valve tissue engineering, appropriate mechanical preconditioning may provide the necessary stimuli to promote proper tissue formation [1–3]. Previous efforts have focused on a mechanistic heart valve (MHV) bioreactor that can mimic the innate mechanical stress states of flexure, flow and stretch in any combination thereof [1]. A fundamental component pertaining to heart valves is its dynamic behavior. Specific fluid-induced shears stress patterns may play a critical role in up-regulating ECM secretion by progenitor cell sources such as bone marrow derived stem cells [2] and increasing the possibility of cell differentiation towards a heart valve phenotype. Here, we take a computational predictive modeling approach to identify the specific fluid induced shear stress distributions that are altered as a result of valve-like movement and its resulting implications for tissue growth. Previous results have demonstrated the analogous deformation characteristics of heart valves in a rectangular geometry [2]. We conducted computational fluid dynamic (CFD) simulations of a bioreactor that houses these rectangular-shaped specimens (Fig.1).

Tissue Engineering of Pulmonary Heart Valves on Allogenic Acellular Matrix Conduits : In Vivo Restoration of Valve Tissue

Circulation ◽  
2000 ◽  
Vol 102 (Supplement 3) ◽  
pp. III-50-III-55 ◽  
Author(s):  
G. Steinhoff ◽  
U. Stock ◽  
N. Karim ◽  
H. Mertsching ◽  
A. Timke ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Heart Valves ◽  
Acellular Matrix ◽  
Valve Tissue

scholarly journals Identification of CD34+/PGDFRα+ Valve Interstitial Cells (VICs) in Human Aortic Valves: Association of Their Abundance, Morphology and Spatial Organization with Early Calcific Remodeling

2020 ◽  
Vol 21 (17) ◽  
pp. 6330
Author(s):  
Grzegorz J. Lis ◽  
Andrzej Dubrowski ◽  
Maciej Lis ◽  
Bernard Solewski ◽  
Karolina Witkowska ◽  
...  
Keyword(s):  
Heart Valves ◽  
Spatial Organization ◽  
Three Dimensional ◽  
Interstitial Cells ◽  
Dimensional Structure ◽  
Aortic Valves ◽  
Valve Interstitial Cells ◽  
Valve Tissue ◽  
Early Signs ◽  
Younger Age

Aortic valve interstitial cells (VICs) constitute a heterogeneous population involved in the maintenance of unique valvular architecture, ensuring proper hemodynamic function but also engaged in valve degeneration. Recently, cells similar to telocytes/interstitial Cajal-like cells described in various organs were found in heart valves. The aim of this study was to examine the density, distribution, and spatial organization of a VIC subset co-expressing CD34 and PDGFRα in normal aortic valves and to investigate if these cells are associated with the occurrence of early signs of valve calcific remodeling. We examined 28 human aortic valves obtained upon autopsy. General valve morphology and the early signs of degeneration were assessed histochemically. The studied VICs were identified by immunofluorescence (CD34, PDGFRα, vimentin), and their number in standardized parts and layers of the valves was evaluated. In order to show the complex three-dimensional structure of CD34+/PDGFRα+ VICs, whole-mount specimens were imaged by confocal microscopy, and subsequently rendered using the Imaris (Bitplane AG, Zürich, Switzerland) software. CD34+/PDGFRα+ VICs were found in all examined valves, showing significant differences in the number, distribution within valve tissue, spatial organization, and morphology (spherical/oval without projections; numerous short projections; long, branching, occasionally moniliform projections). Such a complex morphology was associated with the younger age of the subjects, and these VICs were more frequent in the spongiosa layer of the valve. Both the number and percentage of CD34+/PDGFRα+ VICs were inversely correlated with the age of the subjects. Valves with histochemical signs of early calcification contained a lower number of CD34+/PDGFRα+ cells. They were less numerous in proximal parts of the cusps, i.e., areas prone to calcification. The results suggest that normal aortic valves contain a subpopulation of CD34+/PDGFRα+ VICs, which might be involved in the maintenance of local microenvironment resisting to pathologic remodeling. Their reduced number in older age could limit the self-regenerative properties of the valve stroma.

Enhancement of Porosity and Surface Roughness of Cured Phenolic Resin by Ion Implantation

2000 ◽  
Vol 647 ◽  
Author(s):  
R.L. Zimmerman ◽  
D. Ila ◽  
C.C. Smith ◽  
A.L. Evelyn ◽  
D.B. Poker ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Ion Implantation ◽  
Heart Valves ◽  
Phenolic Resin ◽  
Tissue Growth ◽  
Nuclear Reaction Analysis ◽  
Phenolic Resins ◽  
Prosthetic Devices ◽  
Cell Tissue ◽  
Polymeric Carbon

AbstractWe present recent results using ions such as C., O, Si, Fe, Zn, and Au at energies between 100 keV to 10 MeV to increase the roughness and porosity of the partially and fully cured precursor phenolic resins. The fully cured phenolic resin is called Glassy Polymeric Carbon (GPC). GPC is chemically inert, biocompatible and useful for medical applications, such as heart valves and other prosthetic devices. Ion implantation enhances biological cell/tissue growth on, and tissue adhesion to, prosthetic devices made from GPC. We have previously shown that increased porosity of GPC is also useful for drug delivery devices. The porosity of the ion implanted partially and fully cured precursor phenolic resins was measured by introducing lithium from a molten LiCl salt into each sample. By using Li(p,2α) nuclear reaction analysis (NRA) we measured the concentration of Li retention in the pre- and post-implanted samples. The surface roughness was measured using optical microscopy. The curing process was monitored using micro-Raman microscopy. We have correlated the NRA measurements of increased pore availability with the observations of increased surface roughness.

Biomechanical Analysis of Embryonic Atrioventricular Valvulogenesis

2011 ◽  
Author(s):  
Philip R. Buskohl ◽  
Russell A. Gould ◽  
Jonathan T. Butcher
Keyword(s):  
Cell Mechanics ◽  
Heart Valves ◽  
Complex Interaction ◽  
Biomechanical Analysis ◽  
Valve Tissue ◽  
Valve Development ◽  
Aspiration Technique ◽  
Testing Techniques ◽  
Compliant Material ◽  
Geometric Effects

Heart valve development is directed by a complex interaction of molecular and mechanical cues[1]. Both molecular and mechanical based approaches are needed to clarify these relationships. Many technologies exist for the former, but the short length scale and super-compliant material properties of embryonic valve tissue make conventional mechanical testing techniques ineffective. The pipette aspiration technique has been a useful tool in cell mechanics[2] and has recently been applied to adult valve leaflets[3]. Geometric effects of thin, planar tissues however compromise the utility of aspiration based measurements. Herein, we utilize pipette aspiration and a novel uni-axial micro-tensile testing apparatus to quantify the biomechanical evolution of avian embryonic heart valves. We then relate biomechanical stiffening to changes in underlying structural composition.

Tissue engineering of heart valves: Monocyte chemotactic activity in decellularized heart valve tissue

2004 ◽  
Vol 52 (S 1) ◽  
Author(s):  
E Rieder ◽  
MT Kasimir ◽  
G Seebacher ◽  
E Wolner ◽  
P Simon ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Heart Valve ◽  
Heart Valves ◽  
Chemotactic Activity ◽  
Valve Tissue ◽  
Heart Valve Tissue

scholarly journals Radiation Enhanced Porosity and Roughness of Biomaterials

2000 ◽  
Vol 629 ◽  
Author(s):  
A. L. Evelyn ◽  
M. G. Rodrigues ◽  
D. Ila ◽  
R. L. Zimmerman ◽  
D. B. Poker ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Heart Valves ◽  
Tissue Growth ◽  
Nuclear Reaction Analysis ◽  
Phenolic Resins ◽  
Energetic Ions ◽  
Prosthetic Devices ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cell Tissue

ABSTRACTGlassy Polymeric Carbon (GPC), made from cured phenolic resins, is sufficiently chemically inert and biocompatible that it is suitable for medical applications, such as heart valves and other prosthetic devices. We have used energetic ion bombardment of the partially and fully cured precursor phenolic resins to enhance biological cell/tissue growth on, and to increase tissue adhesion to, prosthetic devices made from GPC. GPC samples were bombarded with energetic ions to 10 MeV. The surface topography and increased surface roughness was observed using optical microscopy and atomic force microscopy (AFM). The increased porosity was measured by introducing lithium from a molten LiCl salt into the GPC and using (p, α) nuclear reaction analysis (NRA) to measure the concentration of Li retention in the modified GPC. The NRA measurements of increased pore availability were correlated with the observations of increased surface roughness.

Tissue- and Cell-Level Stress Distributions of the Heart Valve Tissue During Diastole

2013 ◽  
Author(s):  
Siyao Huang ◽  
Hsiao-Ying Shadow Huang
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Stress Transfer ◽  
Tissue Level ◽  
Stress Distributions ◽  
Tissue Microstructure ◽  
Valve Tissue ◽  
Cell Tissue ◽  
Heart Valve Tissue ◽  
Stress States

Heart valves are inhomogeneous microstructure with nonlinear anisotropic properties and constantly experience different stress states during cardiac cycles. However, how tissue-level mechanical forces can translate into altered cellular stress states remains unclear, and associated biomechanical regulation in the tissue has not been fully understood. In the current study, we use an image-based finite element method to investigate factors contributing the stress distributions at both tissue- and cell-levels inside the healthy heart valve tissues. Effects of tissue microstructure, inhomogeneity, and anisotropic material property at different diastole states are discussed to provide a better understanding of structure-mechanics-property interactions, which alters tissue-to-cell stress transfer mechanisms in heart valve tissue. To the best of the authors’ knowledge, this is the first study reporting on the evolution of stress fields at both the tissue- and cellular-levels in valvular tissue, and thus contributes toward refining our collective understanding of valvular tissue micromechanics while providing a computational tool enabling further study of valvular cell-tissue interactions.

A Novel Bioreactor for Tissue Engineered Heart Valves Based on Controlled Cyclic Stretching

2009 ◽  
Author(s):  
Zeeshan H. Syedain ◽  
Robert T. Tranquillo
Keyword(s):  
Heart Valves ◽  
Pediatric Patients ◽  
Tissue Growth ◽  
Cyclic Stretch ◽  
Pulse Flow ◽  
Promising Alternative ◽  
Cyclic Stretching ◽  
Tissue Engineered Heart Valve ◽  
Tissue Engineered Heart Valves ◽  
Mechanical Stretching

The tissue-engineered heart valve (TEHV) is considered a promising alternative for valve replacement, especially in pediatric patients. To date, most TEHVs have been cultured in pulse-flow bioreactors to generate mechanical loads and deformations leading to tissue growth (1, 2). Our approach has been to apply controlled mechanical stretching to induce tissue growth (3). In this study, a novel controlled cyclic stretch bioreactor is presented to enhance functional properties of TEHVs.

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