Tracings of Interaction Between Myoblasts Under Shear Flow in Vitro

2021 ◽  
Author(s):  
Shigehiro Hashimoto ◽  
Takashi Yokomizo
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Shear Flow ◽  
Flow Direction ◽  
Time Lapse ◽  
Adjacent Cell ◽  
Contact Ratio ◽  
Rotating Disc ◽  
Wall Shear

Abstract How does the group of cells make orientation perpendicular to the flow direction? How does contact with an adjacent cell affect the orientation of the cell? The orientation of a cell according to the neighbor cell under shear flow fields has been traced in vitro. A Couette type flow device with parallel discs was manufactured for the cell culture under the controlled constant wall shear stress. Cells (C2C12: mouse myoblast cell line) were cultured on the lower disc while applying the shear flow in the medium by the upper rotating disc. After culture for 24 hours without flow for adhesion of cells, 2 Pa of the constant wall shear stress was continuously applied in the incubator for 7 days. The behavior of each cell was traced by time-lapse images observed by an inverted phase contrast microscope placed in an incubator. The experiment shows the following results quantitatively by parameters: the contact ratio, and the angle between major axes of cells approximated to ellipsoids. As the ratio of the contact length with the adjacent cell to the pericellular length increases in the two-dimensional projection images, the adjacent cells tend to be oriented in parallel with each other.

Behavior of Myoblast Under Shear Stress in Couette Type of Flow

2020 ◽  
Author(s):  
Shigehiro Hashimoto
Keyword(s):  
Shear Stress ◽  
Shear Flow ◽  
Flow Direction ◽  
Experimental System ◽  
Longitudinal Axis ◽  
Time Lapse ◽  
Rotating Speed ◽  
Culture Plate ◽  
Myoblast Cell

Abstract Behavior of myoblast has been investigated under the uniform shear flow in vitro. The culture medium was sandwiched with the constant gap between the lower stationary culture plate and the upper rotating parallel plate to make a Couette type of the shear flow. By the rotating speed of the upper disk, the wall shear stress (τ) on the lower culture plate was controlled. C2C12 (mouse myoblast cell) was used in the test. After cultivation without flow for 24 hours for adhesion of cells on the lower plate, τ < 2 Pa was continuously applied on cells for 7 days in the incubator. Behavior of each cell was traced at the time lapse images observed by an inverted phase contrast microscope placed in an incubator. Experimental results show that cells differentiate to myotubes under τ < 2 Pa. Both the cell cycle and the cell length tend to scatter in the wider range, and the longitudinal axis of each cell tends to align to the flow direction by the shear stress of 1 Pa. The experimental system is useful to study quantitative relationships between the shear stress and the cell behavior: deformation, orientation, and differentiation.

Behavior of Cell Under Wall Shear Stress in Flow Field: Comparison Among Cell Types

2021 ◽  
Author(s):  
Shigehiro Hashimoto ◽  
Kiyoshi Yoshinaka ◽  
Hiroki Yonezawa
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Stress Field ◽  
Flow Direction ◽  
Umbilical Vein ◽  
Cell Activity ◽  
Time Lapse ◽  
Mouse Fibroblast ◽  
Wall Shear ◽  
Shear Stress Field

Abstract Does the hysteresis effect remain in each cell after division? In the present study, the cell activity has been investigated after division under a shear stress field. To apply the constant shear stress field on cells, a Couette type flow device has been manufactured: between parallel walls (a lower stationary culture disk, and an upper rotating disk) with a constant gap. The wall shear stress was controlled by the rotating speed of the upper disk. Four types of cells were used in the test: C2C12 (mouse myoblast cell line), HUVEC (Human Umbilical Vein Endothelial Cells), 3T3-L1 (mouse fat precursor cells), and L929 (mouse fibroblast connective tissue). After cultivation without flow for 24 hours for adhesion of cells on the lower plate, the shear stress of 1 Pa was continuously applied on cells for 7 days at 310 K. The behavior (alignment and deformation) of each cell was traced at the time lapse image observed by an inverted phase contrast microscope placed in an incubator. The experimental results show the following behavior of each type of cell: C2C12 tends to return to the same direction as that of before division. Deformed 3T3-L1 tends to tilt to the flow direction.

Drag Reduction by Boundary Layer Control With Passively Moving Wall

2013 ◽  
Author(s):  
Helge Koch ◽  
Dragan Kozulovic
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Direction ◽  
Mean Flow ◽  
Rotating Disc ◽  
Moving Wall ◽  
Wide Range ◽  
Wall Shear ◽  
Probe Measurements ◽  
Layer Control

There exists a wide range of approaches to reduce the skin friction drag. One of the approaches is to attenuate the no-slip condition by moving the wall in flow direction. This reduces the velocity difference between the mean flow and the wall and thereby the wall shear stress. Actively moving walls are used for nearly all known investigations on this topic. This paper presents a concept for a passive moving wall. The motion of the wall is driven by the wall shear stress itself. For this investigation the moving wall is designed as a rotating disc which is embedded in the surface of a flat plate. One half of the disc is covered, whereas the other part is exposed to the flow. The interaction between the rotating disc and the flow is investigated experimentally by means of flatted Pitot probe measurements and rotation speed measurements.

scholarly journals Investigation of Wall Shear Stress in Cardiovascular Research and in Clinical Practice—From Bench to Bedside

2021 ◽  
Vol 22 (11) ◽  
pp. 5635
Author(s):  
Katharina Urschel ◽  
Miyuki Tauchi ◽  
Stephan Achenbach ◽  
Barbara Dietel
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Cell Function ◽  
Computational Techniques ◽  
Apical Surface ◽  
Cardiovascular Research ◽  
Endothelial Cell Function ◽  
Wall Shear

In the 1900s, researchers established animal models experimentally to induce atherosclerosis by feeding them with a cholesterol-rich diet. It is now accepted that high circulating cholesterol is one of the main causes of atherosclerosis; however, plaque localization cannot be explained solely by hyperlipidemia. A tremendous amount of studies has demonstrated that hemodynamic forces modify endothelial athero-susceptibility phenotypes. Endothelial cells possess mechanosensors on the apical surface to detect a blood stream-induced force on the vessel wall, known as “wall shear stress (WSS)”, and induce cellular and molecular responses. Investigations to elucidate the mechanisms of this process are on-going: on the one hand, hemodynamics in complex vessel systems have been described in detail, owing to the recent progress in imaging and computational techniques. On the other hand, investigations using unique in vitro chamber systems with various flow applications have enhanced the understanding of WSS-induced changes in endothelial cell function and the involvement of the glycocalyx, the apical surface layer of endothelial cells, in this process. In the clinical setting, attempts have been made to measure WSS and/or glycocalyx degradation non-invasively, for the purpose of their diagnostic utilization. An increasing body of evidence shows that WSS, as well as serum glycocalyx components, can serve as a predicting factor for atherosclerosis development and, most importantly, for the rupture of plaques in patients with high risk of coronary heart disease.

Exploring wall shear stress spatiotemporal heterogeneity in coronary arteries combining correlation-based analysis and complex networks with computational hemodynamics

2020 ◽  
Vol 234 (11) ◽  
pp. 1209-1222 ◽  
Author(s):  
Karol Calò ◽  
Giuseppe De Nisco ◽  
Diego Gallo ◽  
Claudio Chiastra ◽  
Ayla Hoogendoorn ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Complex Networks ◽  
Coronary Arteries ◽  
Early Stage ◽  
Flow Direction ◽  
Computational Hemodynamics ◽  
Time Histories ◽  
Wall Shear

Atherosclerosis at the early stage in coronary arteries has been associated with low cycle-average wall shear stress magnitude. However, parallel to the identification of an established active role for low wall shear stress in the onset/progression of the atherosclerotic disease, a weak association between lesions localization and low/oscillatory wall shear stress has been observed. In the attempt to fully identify the wall shear stress phenotype triggering early atherosclerosis in coronary arteries, this exploratory study aims at enriching the characterization of wall shear stress emerging features combining correlation-based analysis and complex networks theory with computational hemodynamics. The final goal is the characterization of the spatiotemporal and topological heterogeneity of wall shear stress waveforms along the cardiac cycle. In detail, here time-histories of wall shear stress magnitude and wall shear stress projection along the main flow direction and orthogonal to it (a measure of wall shear stress multidirectionality) are analyzed in a representative dataset of 10 left anterior descending pig coronary artery computational hemodynamics models. Among the main findings, we report that the proposed analysis quantitatively demonstrates that the model-specific inlet flow-rate shapes wall shear stress time-histories. Moreover, it emerges that a combined effect of low wall shear stress magnitude and of the shape of the wall shear stress–based descriptors time-histories could trigger atherosclerosis at its earliest stage. The findings of this work suggest for new experiments to provide a clearer determination of the wall shear stress phenotype which is at the basis of the so-called arterial hemodynamic risk hypothesis in coronary arteries.

Tracings of Behavior of Myoblasts Cultured Under Couette Type of Shear Flow Between Parallel Disks

2021 ◽  
Author(s):  
Shigehiro Hashimoto ◽  
Hiroki Yonezawa
Keyword(s):  
Shear Stress ◽  
Shear Flow ◽  
Rotating Disk ◽  
Time Lapse ◽  
Mechanical Stimuli ◽  
Parallel Disks ◽  
Before And After ◽  
A Cell

Abstract A cell deforms and migrates on the scaffold under mechanical stimuli in vivo. In this study, a cell with division during shear stress stimulation has been observed in vitro. Before and after division, both migration and deformation of each cell were analyzed. To make a Couette-type shear flow, the medium was sandwiched between parallel disks (the lower stationary culture-disc and the upper rotating disk) with a constant gap. The wall shear stress (1.5 Pa < τ < 2 Pa) on the surface of the lower culture plate was controlled by the rotational speed of the upper disc. Myoblasts (C2C12: mouse myoblast cell line) were used in the test. After cultivation without flow for 24 hours for adhesion of the cells to the lower disk, constant τ was applied to the cells in the incubator for 7 days. The behavior of each cell during shear was tracked by time-lapse images observed by an inverted phase contrast microscope placed in the incubator. Experimental results show that each cell tends to divide after higher activities: deformation and migration. The tendency is remarkable at the shear stress of 1.5 Pa.

In-Vitro Wall Shear Stress Measurements for Microfluid Flows by Using Second-Order SPE Micro-PIV

2007 ◽  
Author(s):  
Han-Sheng Chuang ◽  
Steven T. Wereley
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Measurement Errors ◽  
Pearson Correlation ◽  
Second Order ◽  
Bias Error ◽  
Central Difference ◽  
Micro Piv ◽  
Wall Shear

Conventional single pixel evaluation (SPE) significantly improves the spatial resolution of PIV measurements to the physical limit of a CCD camera based on the forward difference interrogation (FDI). This paper further enhances the computational algorithm to second-order accuracy by simply modifying the numerical scheme with the central difference interrogation (CDI). The proposed central difference scheme basically superposes the forward-time and the backward-time correlation domains, thus resulting in reduced bias error as well as rapid background noise elimination. An assessment of the CDI SPE algorithm regarding the measurement errors was achieved via numerous synthetic images subject to a four-roll mill flow. In addition, preliminary wall shear stress (WSS) measurements regarding different algorithms are also evaluated with an analytical turbulent boundary flow. CDI scheme showed a 0.32% error deviated from the analytical solution and improved the same error in FFT-based correlation correlation (FFT-CC) by 32.35%. To demonstrate the performance in practice, in-vitro measurements were implemented in a serpentine microchannel made of polydimethyl siloxane (PDMS) for both CDI SPE and spatial cross-correlation. A series of steady-state flow images at five specified regions of interest were acquired using micro-PIV system. Final comparisons of the WSS regarding the Pearson correlation coefficient, R2, between the numerical schemes and the simulations showed that an overall result was improved by CDI SPE due to the fine resolution and the enhanced accuracy.

Design and Analysis of a Shear Stress Sensor for Microcirculation Investigations (Invited Paper)

2003 ◽  
Author(s):  
Risa Robinson ◽  
Lynn Fuller ◽  
Harvey Palmer ◽  
Mary Frame
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Computational Technique ◽  
Flow Modification ◽  
Stress Sensors ◽  
Shear Stress Sensors ◽  
Wall Shear

Blood flow regulation in the microvascular network has been investigated by means of computational fluid dynamics, in vivo particle tracking and microchannel models. It is evident from these studies that shear stress along the wall is a key factor in the communication network that results in blood flow modification, yet current methods for shear stress determination are acknowledged to be imprecise. Micromachining technology allows for the development of implantable shear stress sensors that will enable us to monitor wall shear stress at multiple locations in arteriole bifurcations. In this study, a microchannel was employed as an in vitro model of a microvessel. Thermal shear stress sensors were used to mimic the endothelial cells that line the vessel wall. A three dimensional computational model was created to simulate the system’s thermal response to the constant temperature control circuit and related wall shear stress. The model geometry included a silicon wafer section with all the fabrication layers — silicon dioxide, poly silicon resistor, silicon nitride — and a microchannel with cross section 17 μm × 17 μm. This computational technique was used to optimize the dimensions of the system for a 0.01 Reynolds number flow at room temperature in order to reduce the amount of heat lost to the substrate and to predict and maximize the signal response. Results of the design optimization are presented and the fabrication process discussed.

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