Oscillating shear stress mediates mesenchymal transdifferentiation of EPCs by the Kir2.1 channel

2020 ◽  
Vol 35 (10) ◽  
pp. 1473-1482 ◽  
Author(s):  
Jifeng Li ◽  
Yanting He ◽  
Hongnan Bu ◽  
Meiyue Wang ◽  
Jie Yu ◽  
...  
2001 ◽  
Author(s):  
Dalin Tang ◽  
Chun Yang ◽  
Shunnichi Kobayashi

Abstract There has been increasing evidence that severe stenosis may cause artery compression and plaque cap rupture leading to heart attack and stroke. The physiological conditions under which that may occur and mechanisms involved are not well understood. It has been known that severe stenosis causes critical flow and wall mechanical conditions such as flow limitation, flow separation, low and oscillating shear stress distal to the stenosis, high shear stress and low or even negative flow pressure at the throat of stenosis, artery compression or even collapse. Those conditions are related to limitation of blood supply, intimal thickening and thrombosis formation, endothelism damage, platelet activation and aggregation, plaque cap rupture (for review, see [1,2]). Due to the complexity of the problem and lack of experimental data for mechanical properties of arteries under both expansion and compression, previous models were limited primarily to flow behaviors and with various limitations (axisymmetry, rigid wall, small strain, small pressure gradient). In this paper, experimental data for artery mechanical properties under physiological conditions were measured and a 3-d computational model is introduced to investigate flow behaviors and wall stress and strain distributions with fluid-structure interactions to better understand the mechanism involved in artery compression and plaque cap rupture.


2019 ◽  
Vol 245 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Lan Jia ◽  
Lihua Wang ◽  
Fang Wei ◽  
Chen Li ◽  
Zhe Wang ◽  
...  

Hemodynamic forces have an important role in venous intimal hyperplasia, which is the main cause of arteriovenous fistula dysfunction. Endothelial cells (ECs) constantly exposed to the shear stress of blood flow, converted the mechanical stimuli into intracellular signals, and interacted with the underlying vascular smooth muscle cells (VSMCs). Caveolin-1 is one of the important mechanoreceptors on cytomembrane, which is related to vascular abnormalities. Extracellular signal-regulated kinase1/2 (ERK1/2) pathway is involved in the process of VSMCs proliferation and migration. In the present study, we explore the effects of Caveolin-1-ERK1/2 pathway and uremia toxins on the endothelial cells and VSMCs following shear stress application. Different shear stress was simulated with a ECs/VSMCs cocultured parallel-plate flow chamber system. Low shear stress and oscillating shear stress up-regulated the expression of fibroblast growth factor-4, platelet-derived growth factor-BB, vascular endothelial growth factor-A, ERK1/2 phosphorylation in endothelial cells, and proliferation and migration of VSMCs but down-regulated the Caveolin-1 expression in endothelial cells. Uremia toxin induces the proliferation and migration of VSMCs but not in a Caveolin-1-dependent manner in the static environment. Low shear stress-induced proliferation and migration of VSMCs is inhibited by Caveolin-1 overexpression and ERK1/2 suppression. Shear stress-regulated VSMC proliferation and migration is an endothelial cells-dependent process. Low shear stress and oscillating shear stress exert atherosclerotic influences on endothelial cells and VSMCs. Low shear stress modulated proliferation and migration of VSMCs through Caveolin-1-ERK1/2 pathway, which suggested that Caveolin-1 and ERK1/2 can be used as a new therapeutic target for the treatment of arteriovenous fistula dysfunction. Impact statement Venous intimal hyperplasia is the leading cause of arteriovenous fistula (AVF) dysfunction. This article reports that shear stress-regulated vascular smooth muscle cells (VSMCs) proliferation and migration is an endothelial cell (EC)-dependent process. Low shear stress (LSS) and oscillating shear stress (OSS) exert atherosclerotic influences on the ECs and VSMCs. LSS-induced proliferation and migration of VSMCs is inhibited by Caveolin-1 overexpression and extracellular signal-regulated kinase1/2 (ERK1/2) suppression, which suggested that Caveolin-1 and ERK1/2 can be used as a new therapeutic target for the treatment of AVF dysfunction.


Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Constantin Fetecau ◽  
Dumitru Vieru ◽  
Corina Fetecau

AbstractThe velocity field corresponding to the unsteady motion of a viscous fluid between two side walls perpendicular to a plate is determined by means of the Fourier transforms. The motion of the fluid is produced by the plate which after the time t = 0, applies an oscillating shear stress to the fluid. The solutions that have been obtained, presented as a sum of the steady-state and transient solutions satisfy the governing equation and all imposed initial and boundary conditions. In the absence of the side walls they are reduced to the similar solutions corresponding to the motion over an infinite plate. Finally, the influence of the side walls on the fluid motion, the required time to reach the steady-state, as well as the distance between the walls for which the velocity of the fluid in the middle of the channel is unaffected by their presence, are established by means of graphical illustrations.


2010 ◽  
Vol 39 (1) ◽  
pp. 402-413 ◽  
Author(s):  
Joanna Rossi ◽  
Paul Jonak ◽  
Leonie Rouleau ◽  
Lisa Danielczak ◽  
Jean-Claude Tardif ◽  
...  

Author(s):  
Tracy M. Cheung ◽  
George A. Truskey

As endothelial cells (ECs) age, morphological and physiological changes occur that may alter macromolecular transport and cause subsequent disease development. ECs in atherosclerotic regions exhibit high cell turnover and high levels of oxidative stress due to transient flow patterns and low and oscillating shear stress. This leads to replicative or stress-induced senescence. Resveratrol indirectly reverses senescence-associated phenotypes via competitive inhibition of cAMP-degrading phosphodiesterases (PDEs). Elevated levels of membrane-associated cAMP activate the cyclic AMP-regulated guanosine nucleotide exchange factor Epac1 which, in turn, leads to guanosine triphosphate (GTP) binding to the small G protein Rap1. GTP bound Rap1 activates the deacetylase SIRTUIN1 (SIRT1) but also causes changes to the cortical cytoskeleton and organization of VE-cadherin mechanosensor in the endothelial junctions (Figure 1).


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