Novel cone-and-plate flow chamber with controlled distribution of wall fluid shear stress

2019 ◽  
Vol 106 ◽  
pp. 140-148
Author(s):  
Chongyang Ye ◽  
Shahid Ali ◽  
Qing Sun ◽  
Mengmeng Guo ◽  
Yixuan Liu ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Shear Stress ◽  
Flow Chamber ◽  
Fluid Shear

Simultaneous Measurement of Morphology and Traction Forces of Endothelial Cells Under Fluid Shear Stress

2012 ◽  
Author(s):  
Toshiro Ohashi ◽  
Yusaku Niida ◽  
Ryoichi Tanaka ◽  
Masaaki Sato
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Morphological Changes ◽  
Traction Force ◽  
Flow Chamber ◽  
Fluid Shear ◽  
Traction Forces ◽  
Contractile Forces

Under fluid shear stress, vascular endothelial cells (ECs) cultured in a monolayer are known to exhibit marked elongation and orientation to the direction of flow [1]. It is also observed that intracellular F-actin filament distributions changed depending on the amplitude of shear stress and the direction of flow, suggesting morphology of ECs is closely related to cytoskeltal structure [2]. ECs generate contractile forces by the actin-myosin machinery and the forces are transmitted to underlying substrate as cellular traction forces. We hypothesize that reorganization of cytoskeletal structures regulates traction forces in ECs exposed to fluid shear stress. In order to measure traction forces and cell morphology simultaneously, we have developed a newly designed flow-imposed device in which a substrate with arrays of elastomeric micropillars (3 μm in diameter and 10 μm in height) is integrated on the bottom of a parallel plate flow chamber. In this study, traction force distributions and morphological changes in GFP-tagged ECs in a monolayer under fluid flow are simultaneously evaluated through image analysis in a spatial and a temporal manner.

Fluid shear stress increases membrane fluidity in endothelial cells: a study with DCVJ fluorescence

2000 ◽  
Vol 278 (4) ◽  
pp. H1401-H1406 ◽  
Author(s):  
Mark A. Haidekker ◽  
Nicolas L'Heureux ◽  
John A. Frangos
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Membrane Fluidity ◽  
Fluid Shear Stress ◽  
Cell Metabolism ◽  
Cell Monolayer ◽  
Flow Chamber ◽  
Fluid Shear ◽  
Parallel Plate Flow Chamber ◽  
Entire Cell

Fluid shear stress (FSS) has been shown to be an ubiquitous stimulator of mammalian cell metabolism. Although many of the intracellular signal transduction pathways have been characterized, the primary mechanoreceptor for FSS remains unknown. One hypothesis is that the cytoplasmic membrane acts as the receptor for FSS, leading to increased membrane fluidity, which in turn leads to the activation of heterotrimetric G proteins (13). 9-(Dicyanovinyl)-julolidine (DCVJ) is a fluorescent probe that integrates into the cell membrane and changes its quantum yield with the viscosity of the environment. In a parallel-plate flow chamber, confluent layers of DCVJ-labeled human endothelial cells were exposed to different levels of FSS. With increased FSS, a reduced fluorescence intensity was observed, indicating an increase of membrane fluidity. Step changes of FSS caused an approximately linear drop of fluorescence within 5 s, showing fast and almost full recovery after shear cessation. A linear dose-response relationship between shear stress and membrane fluidity changes was observed. The average fluidity increase over the entire cell monolayer was 22% at 26 dyn/cm2. This study provides evidence for a link between FSS and membrane fluidity, and suggests that the membrane is an important flow mechanosensor of the cell.

scholarly journals Fluid-Solid Coupling Simulation of Wall Fluid Shear Stress on Cells under Gradient Fluid Flow

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiao Zhang ◽  
Yan Gao ◽  
Bo Huo
Keyword(s):  
Shear Stress ◽  
Cell Migration ◽  
Cell Surface ◽  
Fluid Shear Stress ◽  
Flow Chamber ◽  
Bottom Plate ◽  
Finite Element Models ◽  
Fluid Shear ◽  
Osteoclast Precursors ◽  
Cell Spacing

Fluid shear stress (FSS) plays a crucial role for cell migration within bone cavities filled with interstitial fluid. Whether the local wall FSS distribution on cell surface depends on the global gradient FSS of flow field should be clarified to explain our previous experimental observation. In this study, finite element models of discretely distributed or hexagonal closely packed cells adherent on the bottom plate in a modified plate flow chamber with different global FSS gradient were constructed. Fluid-solid coupling simulation of wall fluid shear stress on cells was performed, and two types of data analysis methods were used. The results showed that the profile of local FSS distribution on cell surface coincides with the angle of cell migration determined in the previous study, suggesting that RAW264.7 osteoclast precursors may sense the global FSS gradient and migrate toward the low-FSS region under a high gradient. For hexagonal closely packed cells, this profile on the surface of central cells decreased along with the increase of cell spacing, which may be caused by the higher local FSS difference along the direction of FSS gradient in the regions close to the bottom plate. This study may explain the phenomenon of the targeted migration of osteoclast precursors under gradient FSS field and further provide insights into the mechanism of mechanical stimulation-induced bone remodeling.

scholarly journals Epigenetic Changes During Mechanically Induced Osteogenic Lineage Commitment

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Julia C. Chen ◽  
Mardonn Chua ◽  
Raymond B. Bellon ◽  
Christopher R. Jacobs
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Methylation Status ◽  
Lineage Commitment ◽  
Fluid Shear ◽  
Osteogenic Lineage ◽  
Osteogenic Markers ◽  
Heterochromatin Structure

Osteogenic lineage commitment is often evaluated by analyzing gene expression. However, many genes are transiently expressed during differentiation. The availability of genes for expression is influenced by epigenetic state, which affects the heterochromatin structure. DNA methylation, a form of epigenetic regulation, is stable and heritable. Therefore, analyzing methylation status may be less temporally dependent and more informative for evaluating lineage commitment. Here we analyzed the effect of mechanical stimulation on osteogenic differentiation by applying fluid shear stress for 24 hr to osteocytes and then applying the osteocyte-conditioned medium (CM) to progenitor cells. We analyzed gene expression and changes in DNA methylation after 24 hr of exposure to the CM using quantitative real-time polymerase chain reaction and bisulfite sequencing. With fluid shear stress stimulation, methylation decreased for both adipogenic and osteogenic markers, which typically increases availability of genes for expression. After only 24 hr of exposure to CM, we also observed increases in expression of later osteogenic markers that are typically observed to increase after seven days or more with biochemical induction. However, we observed a decrease or no change in early osteogenic markers and decreases in adipogenic gene expression. Treatment of a demethylating agent produced an increase in all genes. The results indicate that fluid shear stress stimulation rapidly promotes the availability of genes for expression, but also specifically increases gene expression of later osteogenic markers.

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