Computer Simulations of the Blood Flows and the Growth of Stenosis in Arteries With Bends and Bifurcations

2009 ◽  
Author(s):  
Biyue Liu ◽  
Dalin Tang
Keyword(s):  
Shear Stress ◽  
Blood Supply ◽  
Heart Muscle ◽  
Heart Attack ◽  
Computational Models ◽  
Fluid Shear Stress ◽  
The United States ◽  
Human Aorta ◽  
Atherosclerotic Plaques ◽  
Artery Wall

Heart attack and stroke are the chief and the 3rd largest causes of death in the United States, respectively. A heart attack occurs when the blood supply to an area of heart muscle is blocked, usually by a clot in a coronary artery; a stroke occurs when the blood supply to a region of the brain is lost. The most frequent cause of loss of blood supply to brain tissue or to heart muscle is atherosclerosis, which involves complex interactions between the artery wall and the blood flow. Caro et al first suggested that the distribution of fatty streaking in human aorta may be coincident with regions in which the shear rate at the arterial wall is locally reduced [1]. After that, intensive research has been conducted to statistically study the role of shear stress in atherosclerosis and to quantitatively determine the correlation between the low shear stress and the development of atherosclerotic plaques [2–8]. It is widely believed that fluid shear stress acting on the artery wall plays an important role in the pathogenesis of atherosclerosis. The objectives of this project are to investigate how the geometrical adaptation of atherosclerotic plaques is related to the wall shear stress (WSS) and to study the influences of the flow parameters on the growth of the atherosclerotic plaque using computational models.

scholarly journals KNOWLEDGE AND AWARENESS ABOUT ANGINA PECTORIS AMONG PHARMACY STUDENTS

2014 ◽  
Vol 4 ◽  
pp. 81
Author(s):  
Humera Khatoon ◽  
Keyword(s):  
Myocardial Infarction ◽  
Angina Pectoris ◽  
Blood Supply ◽  
Heart Muscle ◽  
Heart Attack ◽  
Pharmacy Students ◽  
Warning Sign ◽  
Chest Discomfort ◽  
Adequate Blood Supply ◽  
Disease Sign

Objective of this study is to determine the awareness among student of Pharm D with Angina Pectoris (AP) regarding the disease, sign & symptoms and treatment.The term Angina Pectoris is applied to varying forms of transient chest discomfort that are attributable to insufficient myocardial oxygen. The classic description of angina is a crushing pain that radiates through the chest and sometimes down the arm, neck, teeth /jaw or into the back, which is usually aggravated by exertion or stress. Angina is a warning sign that the heart muscle is not getting adequate blood supply and specially oxygen and it may lead to myocardial infarction or a heart attack

scholarly journals Intramembrane binding of VE-cadherin to VEGFR2 and VEGFR3 assembles the endothelial mechanosensory complex

2015 ◽  
Vol 208 (7) ◽  
pp. 975-986 ◽  
Author(s):  
Brian G. Coon ◽  
Nicolas Baeyens ◽  
Jinah Han ◽  
Madhusudhan Budatha ◽  
Tyler D. Ross ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Shear Stress ◽  
Transmembrane Domain ◽  
Vascular Development ◽  
Atherosclerotic Plaques ◽  
Fluid Shear ◽  
Disturbed Flow ◽  
Aortic Endothelium ◽  
Precise Role

Endothelial responses to fluid shear stress are essential for vascular development and physiology, and determine the formation of atherosclerotic plaques at regions of disturbed flow. Previous work identified VE-cadherin as an essential component, along with PECAM-1 and VEGFR2, of a complex that mediates flow signaling. However, VE-cadherin’s precise role is poorly understood. We now show that the transmembrane domain of VE-cadherin mediates an essential adapter function by binding directly to the transmembrane domain of VEGFR2, as well as VEGFR3, which we now identify as another component of the junctional mechanosensory complex. VEGFR2 and VEGFR3 signal redundantly downstream of VE-cadherin. Furthermore, VEGFR3 expression is observed in the aortic endothelium, where it contributes to flow responses in vivo. In summary, this study identifies a novel adapter function for VE-cadherin mediated by transmembrane domain association with VEGFRs.

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.

Patterns of fluid shear stress determine atherosclerotic lesion size and vulnerability

2006 ◽  
Vol 45 (3) ◽  
pp. e51
Author(s):  
Caroline Cheng ◽  
Dennie Tempel ◽  
Luc van Damme ◽  
Rien van Haperen ◽  
Rob Krams ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Shear Stress ◽  
Atherosclerotic Lesion ◽  
Lesion Size ◽  
Fluid Shear

scholarly journals Rapid Fabrication of Microfluidic Devices for Biological Mimicking: A Survey of Materials and Biocompatibility

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 346
Author(s):  
Hui Ling Ma ◽  
Ana Carolina Urbaczek ◽  
Fayene Zeferino Ribeiro de Souza ◽  
Paulo Augusto Gomes Garrido Carneiro Leão ◽  
Janice Rodrigues Perussi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cell Viability ◽  
Cellular Response ◽  
Fluid Shear Stress ◽  
Umbilical Vein ◽  
Microfluidic Devices ◽  
In Vitro Assays ◽  
Stress Effect

Microfluidics is an essential technique used in the development of in vitro models for mimicking complex biological systems. The microchip with microfluidic flows offers the precise control of the microenvironment where the cells can grow and structure inside channels to resemble in vivo conditions allowing a proper cellular response investigation. Hence, this study aimed to develop low-cost, simple microchips to simulate the shear stress effect on the human umbilical vein endothelial cells (HUVEC). Differentially from other biological microfluidic devices described in the literature, we used readily available tools like heat-lamination, toner printer, laser cutter and biocompatible double-sided adhesive tapes to bind different layers of materials together, forming a designed composite with a microchannel. In addition, we screened alternative substrates, including polyester-toner, polyester-vinyl, glass, Permanox® and polystyrene to compose the microchips for optimizing cell adhesion, then enabling these microdevices when coupled to a syringe pump, the cells can withstand the fluid shear stress range from 1 to 4 dyne cm2. The cell viability was monitored by acridine orange/ethidium bromide (AO/EB) staining to detect live and dead cells. As a result, our fabrication processes were cost-effective and straightforward. The materials investigated in the assembling of the microchips exhibited good cell viability and biocompatibility, providing a dynamic microenvironment for cell proliferation. Therefore, we suggest that these microchips could be available everywhere, allowing in vitro assays for daily laboratory experiments and further developing the organ-on-a-chip concept.

The rate of fluid shear stress is a potent regulator for the differentiation of mesenchymal stem cells

2019 ◽  
Vol 234 (9) ◽  
pp. 16312-16319 ◽  
Author(s):  
Danyang Yue ◽  
Mengxue Zhang ◽  
Juan Lu ◽  
Jin Zhou ◽  
Yuying Bai ◽  
...  
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Mesenchymal Stem Cells ◽  
Fluid Shear Stress ◽  
Fluid Shear

scholarly journals Fluid shear stress induces osteoblast differentiation and arrests the cell cycle at the G0 phase via the ERK1/2 pathway

2017 ◽  
Vol 16 (6) ◽  
pp. 8699-8708 ◽  
Author(s):  
Liyin Yu ◽  
Xingfeng Ma ◽  
Junqin Sun ◽  
Jie Tong ◽  
Liang Shi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Shear Stress ◽  
Osteoblast Differentiation ◽  
Fluid Shear Stress ◽  
Fluid Shear ◽  
G0 Phase
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