Nox4 and HO‐1 Mediate Effects of Fluid Shear Stress on PLGF in an
            In Vitro
            Model of the Vessel Wall

Nearly all tissues are supported by the lymphatic system for a variety of functions, including the regulation of fluid balance, the removal of particulate matter from the interstitium, as well as the transport of fat from the intestine to the blood, among others. Despite these important functions, very little is known about the particular mechanisms through which the lymphatics fulfill these roles. Lymphedema, a chronic disease characterized by an inability of the lymphatics to maintain tissue homeostasis and estimated to affect over 130 million people worldwide, can result in serious clinical problems for which there are very few beneficial cures or therapies [1]. While fluid stagnation is the primary clinical manifestation of the disease, severe lymphedema is often correlated with tissue remodeling and the gross accumulation of lipid [1]. Given these symptoms, one must consider the breakdown in the lymphatic response to mechanical load (i.e. fluid balance) in order to understand the progression of the disease.

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See-saw rocking: an in vitro model for mechanotransduction research

Journal of The Royal Society Interface ◽

10.1098/rsif.2014.0330 ◽

2014 ◽

Vol 11 (97) ◽

pp. 20140330 ◽

Cited By ~ 7

Author(s):

R. P. Tucker ◽

P. Henningsson ◽

S. L. Franklin ◽

D. Chen ◽

Y. Ventikos ◽

...

Keyword(s):

Shear Stress ◽

Fluid Shear Stress ◽

Fluid Velocity ◽

Maximum Shear Stress ◽

Cell Monolayer ◽

Research Progress ◽

Fluid Shear ◽

Time Points ◽

Vitro Model

In vitro mechanotransduction studies, uncovering the basic science of the response of cells to mechanical forces, are essential for progress in tissue engineering and its clinical application. Many varying investigations have described a multitude of cell responses; however, as the precise nature and magnitude of the stresses applied are infrequently reported and rarely validated, the experiments are often not comparable, limiting research progress. This paper provides physical and biological validation of a widely available fluid stimulation device, a see-saw rocker, as an in vitro model for cyclic fluid shear stress mechanotransduction. This allows linkage between precisely characterized stimuli and cell monolayer response in a convenient six-well plate format. Models of one well were discretized and analysed extensively using computational fluid dynamics to generate convergent, stable and consistent predictions of the cyclic fluid velocity vectors at a rocking frequency of 0.5 Hz, accounting for the free surface. Validation was provided by comparison with flow velocities measured experimentally using particle image velocimetry. Qualitative flow behaviour was matched and quantitative analysis showed agreement at representative locations and time points. Maximum shear stress of 0.22 Pa was estimated near the well edge, and time-average shear stress ranged between 0.029 and 0.068 Pa. Human tenocytes stimulated using the system showed significant increases in collagen and GAG secretion at 2 and 7 day time points. This in vitro model for mechanotransduction provides a versatile, flexible and inexpensive method for the fluid shear stress impact on biological cells to be studied.

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Turbulent fluid shear stress induces vascular endothelial cell turnover in vitro.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.83.7.2114 ◽

1986 ◽

Vol 83 (7) ◽

pp. 2114-2117 ◽

Cited By ~ 550

Author(s):

P. F. Davies ◽

A. Remuzzi ◽

E. J. Gordon ◽

C. F. Dewey ◽

M. A. Gimbrone

Keyword(s):

Shear Stress ◽

Endothelial Cell ◽

Fluid Shear Stress ◽

Vascular Endothelial Cell ◽

Vascular Endothelial ◽

Cell Turnover ◽

Fluid Shear ◽

Turbulent Fluid

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ShearFAST: a user-friendly in vitro toolset for high throughput, inexpensive fluid shear stress experiments.

10.1101/2020.01.31.929513 ◽

2020 ◽

Author(s):

Thomas Brendan Smith ◽

Alessandro Marco De Nunzio ◽

Kamlesh Patel ◽

Haydn Munford ◽

Tabeer Alam ◽

...

Keyword(s):

Shear Stress ◽

High Throughput ◽

Fluid Shear Stress ◽

Tracking System ◽

Frequency Measurement ◽

Camera Motion ◽

Fluid Shear ◽

Mean Frequency

Fluid shear stress is a key modulator of cellular physiology in vitro and in vivo, but its effects are under-investigated due to requirements for complicated induction methods. Herein we report the validation of ShearFAST; a smartphone application that measures the rocking profile on a standard laboratory cell rocker and calculates the resulting shear stress arising in tissue culture plates. The accuracy with which this novel approach measured rocking profiles was validated against a graphical analysis, and also against measures reported by an 8-camera motion tracking system. ShearFASTs angle assessments correlated well with both analyses (r ≥0.99, p ≤0.001) with no significant differences in pitch detected across the range of rocking angles tested. Rocking frequency assessment by ShearFAST also correlated well when compared to the two independent validatory techniques (r ≥0.99, p ≤0.0001), with excellent reproducibility between ShearFAST and video analysis (mean frequency measurement difference of 0.006 ± 0.005Hz) and motion capture analysis (mean frequency measurement difference of 0.008 ± 0.012Hz). These data make the ShearFAST assisted cell rocker model make it an attractive approach for economical, high throughput fluid shear stress experiments. Proof of concept data presented reveals a protective effect of low-level shear stress on renal proximal tubule cells submitted to simulations of pretransplant storage.

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Quantifying Lymphatic Endothelial Cell Morphological Changes in Response to Fluid Shear Stress, Cyclic Strain, or Combined Stress and Strain In Vitro

The FASEB Journal ◽

10.1096/fasebj.2021.35.s1.03528 ◽

2021 ◽

Vol 35 (S1) ◽

Author(s):

Caleb Davis ◽

Raghuveer Lalitha Sridhar ◽

Sanjukta Chakraborty ◽

David Zawieja ◽

Michael Moreno

Keyword(s):

Shear Stress ◽

Endothelial Cell ◽

Fluid Shear Stress ◽

Morphological Changes ◽

Cyclic Strain ◽

Lymphatic Endothelial Cell ◽

Stress And Strain ◽

Combined Stress ◽

Fluid Shear

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Physiological fluid shear stress causes downregulation of endothelin-1 mRNA in bovine aortic endothelium

AJP Cell Physiology ◽

10.1152/ajpcell.1992.263.2.c389 ◽

1992 ◽

Vol 263 (2) ◽

pp. C389-C396 ◽

Cited By ~ 200

Author(s):

A. Malek ◽

S. Izumo

Keyword(s):

Shear Stress ◽

Fluid Shear Stress ◽

Fluid Velocity ◽

Low Frequency ◽

Turbulent Shear ◽

Specific Response ◽

Dependent Manner ◽

Fluid Shear ◽

Endothelin 1

We report here that the level of endothelin-1 (ET-1) mRNA from bovine aortic endothelial cells grown in vitro is rapidly (within 1 h of exposure) and significantly (fivefold) decreased in response to fluid shear stress of physiological magnitude. The downregulation of ET-1 mRNA occurs in a dose-dependent manner that exhibits saturation above 15 dyn/cm2. The decrease is complete prior to detectable changes in endothelial cell shape and is maintained throughout and following alignment in the direction of blood flow. Peptide levels of ET-1 secreted into the media are also reduced in response to fluid shear stress. Cyclical stretch experiments demonstrated no changes in ET-1 mRNA, while increasing media viscosity with dextran showed that the downregulation is a specific response to shear stress and not to fluid velocity. Although both pulsatile and turbulent shear stress of equal time-average magnitude elicited the same decrease in ET-1 mRNA as steady laminar shear (15 dyn/cm2), low-frequency reversing shear stress did not result in any change. These results show that the magnitude as well as the dynamic character of fluid shear stress can modulate expression of ET-1 in vascular endothelium.

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