Laminar shear stress is considered to improve endothelial cell (EC) function. However, the underlying mechanism is unclear. Autophagy has been found to protect cell survival under stress. In this study, the effect of laminar shear stress on EC autophagy and its potential mechanism were explored. The autophagic markers, Beclin 1 and LC3 II, in human umbilical vascular endothelial cells increased after laminar shear stress treatment. Meanwhile, the autophagic substrate, p62, decreased. The protein level of Rab4 increased under laminar shear stress. When pretreated with Rab4 siRNA, the increased levels of Beclin 1 and LC3 II were attenuated and p62 levels significantly increased. In addition, the MCP level and the adhesion of monocytes were also obviously increased by Rab4 siRNA. Laminar shear stress upregulated Rab4 expression, which contributed to improved EC autophagy and function.
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http://dx.doi.org/10.1089/dna.2015.3041 | DOI Listing |
Arterioscler Thromb Vasc Biol
December 2024
Department of Pediatrics (T.S., J.-R.M., Y.H.C., J.M.S., J. Kaplan, A.C., L.W., D.G., S.T., S.I., M.D., W.Y., A.L.M., M.R.).
Background: Computational modeling indicated that pathological high shear stress (HSS; 100 dyn/cm) is generated in pulmonary arteries (PAs; 100-500 µm) in congenital heart defects causing PA hypertension (PAH) and in idiopathic PAH with occlusive vascular remodeling. Endothelial-to-mesenchymal transition (EndMT) is a feature of PAH. We hypothesize that HSS induces EndMT, contributing to the initiation and progression of PAH.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Department of Mechanical Engineering, Inha University, 100, Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea.
This work's objective is to investigate the laminar steady flow characteristics of non-Newtonian nano-fluids in a developed chaotic microdevice known as a two-layer crossing channels micromixer (TLCCM). The continuity equation, the 3D momentum equations, and the species transport equations have been solved numerically at low Reynolds numbers with the commercial CFD software Fluent. A procedure has been verified for non-Newtonian flow in studied geometry that is continuously heated.
View Article and Find Full Text PDFComput Biol Med
January 2025
Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India.
Investigating magnetic blood flow characteristics through arteries and micron-size channels for clinical therapies in biomedicine is becoming increasingly important with the rise of point-of-care diagnostics devices. A computational fluid dynamics (CFD) investigation is conducted to explore blood flow within a coronary artery affected by an elliptical stenosis near the artery wall under the influence of a magnetic field. The novelty of our study is the integration of Navier-Stokes and Maxwell's equations to calculate body forces on fluid flow, coupled with the application of magnetic fields both longitudinally and vertically, and the use of the Carreau-Yasuda model to analyse non-Newtonian blood rheology.
View Article and Find Full Text PDFComput Biol Med
January 2025
Center for Digital Cardiovascular Innovations, Cardiovascular Division, Miller School of Medicine, Miami, FL, USA. Electronic address:
Objective: This study aims to investigate the micro-hemodynamic effects of strut malapposition in patient-specific stented coronary bifurcations.
Methods: Using the mapping-back technique, three-dimensional reconstructions of clinical post-stenting artery bifurcations with strut malapposition were accurately generated from optical coherence tomography scans of 9 patients. Computational fluid dynamics (CFD) simulations were then conducted with these models to examine the impact of strut malapposition on various fluid dynamic parameters, including flow patterns, vorticity, strain rates, viscosity, and wall shear stress (WSS).
ACS Appl Mater Interfaces
November 2024
Zhejiang Provincial Engineering Center of Integrated Manufacturing Technology and Intelligent Equipment, Hangzhou City University, Hangzhou 310015, China.
A strategy for fabrication of macroporous hydrogels through 3D printing assisted by molding and multiple microfluidic bubble-templating nozzles is proposed here. This approach aims to address the challenges faced by methods for 3D printing macroporous hydrogels, such as difficulties in precisely controlling the spatial distribution of macropores, limited porosity, and low resolution of external boundaries due to the poor mechanical properties of hydrogel solutions as printing ink. In this method, fast-switching microfluidic bubble-templating nozzles of varying sizes allowed for precise control of target pore sizes over a wide range.
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