Effects of Fluid Shear Stress on Endothelial Cell Invasion Into Three-Dimensional Matrices

2007 ◽  
Author(s):  
Hojin Kang ◽  
Kayla J. Bayless ◽  
Roland Kaunas
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Invasion ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Shear Stresses ◽  
Collagen Gels ◽  
Fluid Shear

We have previously developed a cell culture model to study the effects of angiogenic factors, such as sphingosine-1-phosphate (S1P), on the invasion of endothelial cells into the underlying extracellular matrix. In addition to biochemical stimuli, vascular endothelial cells are subjected to fluid shear stress due to blood flow. The present study is aimed at determining the effects of fluid shear stress on endothelial cell invasion into collagen gels. A device was constructed to apply well-defined fluid shear stresses to confluent human umbilical vein endothelial cells (HUVECs) seeded on collagen gels. Fluid shear stress induced significant increases in cell invasion with a maximal induction at ∼5 dyn/cm2. These results provide evidence that fluid shear stress is a significant stimulus for endothelial cell invasion and may play a role in regulating angiogenesis.

The Dynamic Response of Vascular Endothelial Cells to Fluid Shear Stress

1981 ◽  
Vol 103 (3) ◽  
pp. 177-185 ◽  
Author(s):  
C. F. Dewey ◽  
S. R. Bussolari ◽  
M. A. Gimbrone ◽  
P. F. Davies
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Dynamic Response ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Shear Stresses ◽  
Vascular Endothelial ◽  
Fluid Shear ◽  
Cell Functions

We have developed an in-vitro system for studying the dynamic response of vascular endothelial cells to controlled levels of fluid shear stress. Cultured monolayers of bovine aortic endothelial cells are placed in a cone-plate apparatus that produces a uniform fluid shear stress on replicate samples. Subconfluent endothelial cultures continuously exposed to 1–5 dynes/cm2 shear proliferate at a rate comparable to that of static cultures and reach the same saturation density (≃ 1.0–1.5 × 105 cells/cm2). When exposed to a laminar shear stress of 5–10 dynes/cm2, confluent monolayers undergo a time-dependent change in cell shape from polygonal to ellipsoidal and become uniformly oriented with flow. Regeneration of linear “wounds” in confluent monolayer appears to be influenced by the direction of the applied force. Preliminary studies indicate that certain endothelial cell functions, including fluid endocytosis, cytoskeletal assembly and nonthrombogenic surface properties, also are sensitive to shear stress. These observations suggest that fluid mechanical forces can directly influence endothelial cell structure and function. Modulation of endothelial behavior by fluid shear stresses may be relevant to normal vessel wall physiology, as well as the pathogenesis of vascular diseases, such as atherosclerosis.

Three Distinct Types of Morphological Responses of Cultured Vascular Endothelial Cells to Physiological Levels of Fluid Shear Stress

2003 ◽  
Author(s):  
Michiaka Masuda ◽  
Keigi Fujiwara
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Random Walk ◽  
Endothelial Cell ◽  
Parallel Plate ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial ◽  
Fluid Shear ◽  
Flow Apparatus

Vascular endothelial cells are known to respond to fluid shear stress. To gain insights into the mechanism of flow response by these cells, various types of in vitro devices in which endothelial cells can be cultured under flowing culture medium have been designed. Using such a device, one can apply known levels of (usually laminar) fluid shear stress to cultured endothelial cells. We have made two types of devices: a viscometer-based cone-and-plate flow apparatus and a parallel plate chamber. The cone-and-plate apparatus is used to do biochemical analyses of flow effects on cells while the parallel plate chamber is used to observe dynamic behavior of endothelial cells under flow. We were able to maintain confluent endothelial cell cultures under flow for over a week in the parallel plate flow apparatus. Using this chamber and high resolution time-lapse video microscopy, we studied morphological changes of endothelial cells exposed to different levels of fluid shear stress. We found that endothelial cells in a confluent monolayer exhibited three types of fluid shear stress level-dependent morphological and motile responses within a narrow fluid shear stress range between 0.1–10 dyn/cm2. Endothelial cells cultured under no flow exhibited variable shapes and no preferred orientation of their long cell axes and showed a jiggling motion. When exposed to fluid shear stress levels of below 0.5 dyn/cm2, endothelial cell morphology and motility were not affected. However, when fluid shear stress levels were increased to 2–4 dyn/cm2, they became polygonal and showed increased random-walk activity. Fluid shear stress over 6 dyn/cm2 caused endothelial cells to initially become polygonal and increase their random-walk activity, but they soon became elongated and aligned in the direction of flow. As the cells elongated and aligned, they migrated in the direction of flow. The average velocity of this directed cell migration was less than that of cells moving randomly under the same flow condition at earlier times. These observations indicate that endothelial cells are able to detect and respond to a surprisingly small change in fluid shear stress. It is possible that endothelial cell physiology in vivo is also regulated by small changes in fluid shear stress and that a fluid shear stress change of a few dynes per cm2 within a certain region of an artery could trigger atherogenesis in that particular location.

Fluid Shear Stress Modulates S1P-Induced Endothelial Cell Invasion Into Three-Dimensional Matrices

2008 ◽  
Author(s):  
Hojin Kang ◽  
Kayla J. Bayless ◽  
Roland Kaunas
Keyword(s):  
Endothelial Cells ◽  
Cell Invasion ◽  
Fluid Shear Stress ◽  
Synergistic Effects ◽  
Umbilical Vein ◽  
Three Dimensional ◽  
Mechanical Stimuli ◽  
Collagen Gels ◽  
Fluid Shear ◽  
Angiogenic Potential

Endothelial cells are subjected to biochemical and mechanical stimuli which regulate their angiogenic potential. We determined the synergistic effects of sphingosine-1-phosphate (S1P) and fluid shear wall stress (WSS) on the invasion of human umbilical vein endothelial cells (HUVECs) into three-dimensional collagen matrices. A collagen gel was incorporated into a parallel-plate flow chamber to apply controlled WSS to the surface of HUVEC monolayers over a period of 24hr. Cell invasion into the gels required the presence of S1P, with the effects of S1P being enhanced by WSS to an extent comparable to growth factor (VEGF + FGF-2) stimulation. The number of invading cells depended on the magnitude of WSS, with a maximal induction at a WSS of ∼5 dyne/cm2. The enhancement of invasion by WSS coincided with the phosphorylation of Akt and MMP-2 activation. These results provide evidence that WSS is a positive modulator of S1P-induced EC invasion into collagen gels and may contribute to the localization of sprouting angiogenesis at regions of low WSS such as post-capillary venules.

Fluid shear stress induces the phosphorylation of small heat shock proteins in vascular endothelial cells

1996 ◽  
Vol 271 (3) ◽  
pp. C994-C1000 ◽  
Author(s):  
S. Li ◽  
R. S. Piotrowicz ◽  
E. G. Levin ◽  
Y. J. Shyy ◽  
S. Chien
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Heat Shock ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Mrna Levels ◽  
Fluid Shear ◽  
Maximum Increase ◽  
Umbilical Vein Endothelial Cells

The small molecular mass heat shock protein of 27 kDa (HSP27) has been shown to influence actin filament dynamics and endothelial cell behavior in ways similar to those observed during laminar flow. We have employed human umbilical vein endothelial cells to determine whether fluid shear stress affects HSP27 expression or phosphorylation. After a shear stress of 16 dyn/cm2, HSP27 became more highly phosphorylated, with maximum increase in phosphorylation levels (3-fold) attained by 30 min and sustained for at least 20 h. HSP27 antigen levels did not change; however, HSP27 mRNA levels decreased by 20% after 16 h. In bovine aortic endothelial cells stably transfected with the wild-type human HSP27 gene, shear stress induced the phosphorylation of both the exogenous human HSP27 and the endogenous bovine HSP25. The product of a transfected mutant HSP27 gene in which the putative phosphorylation sites Ser-15, Ser-78, and Ser-82 had been replaced with Gly was not phosphorylated. Thus the modulation of HSP27 and its activity by shear stress is mediated through a posttranslational mechanism and differs from the shear stress induction of immediate early genes at the level of transcription.

Fluid shear stress stimulates incorporation of hyaluronan into endothelial cell glycocalyx

2006 ◽  
Vol 290 (1) ◽  
pp. H458-H452 ◽  
Author(s):  
Mirella Gouverneur ◽  
Jos A. E. Spaan ◽  
Hans Pannekoek ◽  
Ruud D. Fontijn ◽  
Hans Vink
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Barrier Properties ◽  
Endothelial Glycocalyx ◽  
Stable Cell Line ◽  
Permeability Barrier ◽  
Fluid Shear

Vascular endothelial cells are shielded from direct exposure to flowing blood by the endothelial glycocalyx, a highly hydrated mesh of glycoproteins, sulfated proteoglycans, and associated glycosaminoglycans (GAGs). Recent data indicate that the incorporation of the unsulfated GAG hyaluronan into the endothelial glycocalyx is essential to maintain its permeability barrier properties, and we hypothesized that fluid shear stress is an important stimulus for endothelial hyaluronan synthesis. To evaluate the effect of shear stress on glycocalyx synthesis and the shedding of its GAGs into the supernatant, cultured human umbilical vein endothelial cells (i.e., the stable cell line EC-RF24) were exposed to 10 dyn/cm2 nonpulsatile shear stress for 24 h, and the incorporation of [3H]glucosamine and Na2[35S]O4 into GAGs was determined. Furthermore, the amount of hyaluronan in the glycocalyx and in the supernatant was determined by ELISA. Shear stress did not affect the incorporation of 35S but significantly increased the amount of glucosamine-containing GAGs incorporated in the endothelial glycocalyx [168 (SD 17)% of static levels, P < 0.01] and shedded into the supernatant [231 (SD 41)% of static levels, P < 0.01]. Correspondingly with this finding, shear stress increased the amount of hyaluronan in the glycocalyx [from 26 (SD 24) × 10−4 to 46 (SD 29) × 10−4 ng/cell, static vs. shear stress, P < 0.05] and in the supernatant [from 28 (SD 11) × 10−4 to 55 (SD 16) × 10−4 ng·cell−1·h−1, static vs. shear stress, P < 0.05]. The increase in the amount of hyaluronan incorporated in the glycocalyx was confirmed by a threefold higher level of hyaluronan binding protein within the glycocalyx of shear stress-stimulated endothelial cells. In conclusion, fluid shear stress stimulates incorporation of hyaluronan in the glycocalyx, which may contribute to its vasculoprotective effects against proinflammatory and pro-atherosclerotic stimuli.

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