In vitro flow study in a compliant abdominal aorta phantom with a non-Newtonian blood-mimicking fluid

Investigation of the effect of α1-adrenergic receptor subtypes on the contraction of the abdominal aorta will allow for more effective treatment of hypertension by use of selective antagonists. The aim of the study was to evaluate the participation of α1-adrenergic receptor subtypes in the contractility of the aortic smooth muscle cells in rabbits. The in vitro experiments were performed in isolated tissue preparations from 30 adult female New Zealand rabbits. The abdominal aortic sections were placed in organ bath chambers and contracted with increasing doses of non-selective α1-adrenergic receptor agonist phenylephrine without pre-incubation or after incubation in α1-adrenergic receptor subtype-selective or non-selective antagonists. Separate sections were incubated with increasing concentrations of antagonists. Phenylephrine caused maximal rise in arterial smooth muscle tone to 4.75 ± 0.47 mN. The most potent in blocking phenylephrine induced contraction was 5-metylurapidil (α1A-adrenergic receptor antagonist) followed by phentolamine and prazosin (non-selective α1-adrenergic receptor antagonists); BMY 7378 (α1D-adrenergic receptor antagonist), cyclazosin and L-765.314 (α1B-adrenergic receptor antagonists) were less effective. All antagonists, except BMY 7378 elicited relaxation of non-precontracted aorta in dose dependent manner. Our results indicate that postsynaptic α1A receptors are the most potent in producing rabbit abdominal aorta contraction, while α1B and α1D subtypes are less effective.

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Hemodynamics in the abdominal aorta: a comparison of in vitro and in vivo measurements

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.4.1520 ◽

1994 ◽

Vol 76 (4) ◽

pp. 1520-1527 ◽

Cited By ~ 65

Author(s):

J. E. Moore ◽

S. E. Maier ◽

D. N. Ku ◽

P. Boesiger

Keyword(s):

Abdominal Aorta ◽

Velocity Profiles ◽

Flow Reversal ◽

Infrarenal Aorta ◽

Complex Flow ◽

Flow Measurements ◽

In Vivo Measurements ◽

Made In

In vivo measurements of blood velocity profiles are difficult to obtain and interpret, since the parameters that govern the normally highly complex flow situation may not be fully quantified or understood at the time of measurement. In vitro flow models have been used often to better understand vascular hemodynamics. The assumptions made in the design of these models limit the applicability of the results. In this study, in vitro flow measurements made in a carefully designed model of the abdominal aorta were compared with in vivo measurements obtained with magnetic resonance imaging. In the suprarenal aorta, the velocity profiles were mostly forward and axisymmetric in both the in vitro and in vivo cases. In the infrarenal aorta, there was extensive flow reversal noted near the posterior wall in both cases. In the aortic bifurcation, two peaks of flow reversal were noted near the lateral posterior walls, and M-shaped velocity profiles were observed in late diastole. The in vitro and in vivo measurements exhibited good qualitative agreement. The in vitro model was accurate in modeling the in vivo hemodynamics of the abdominal aorta. The complex phenomena observed in vivo were explained on the basis of knowledge gained from the in vitro study.

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An In-Vitro Flow Study Using an Artificial Circle of Willis Model for Validation of an Existing One-Dimensional Numerical Model

Annals of Biomedical Engineering ◽

10.1007/s10439-019-02211-6 ◽

2019 ◽

Vol 47 (4) ◽

pp. 1023-1037 ◽

Cited By ~ 3

Author(s):

Hongtao Yu ◽

George P. Huang ◽

Bryan R. Ludwig ◽

Zifeng Yang

Keyword(s):

Numerical Model ◽

Circle Of Willis ◽

One Dimensional ◽

Flow Study

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Regional differences in vasculotoxic effects of cyclosporin in rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y95-728 ◽

1995 ◽

Vol 73 (11) ◽

pp. 1661-1668 ◽

Cited By ~ 6

Author(s):

Marleen Verbeke ◽

Leo de Ridder ◽

Johan Van de Voorde ◽

Norbert Lameire

Keyword(s):

Thoracic Aorta ◽

Abdominal Aorta ◽

Regional Differences ◽

Treatment Schedule ◽

Study Protocols ◽

Relaxation Responses ◽

Thoracic And Abdominal ◽

And Control

Studies on cyclosporin-induced vasculotoxicity often yielded discrepant results, possibly as a result of differences in study protocols. The aim of the present study was to analyse cyclosporin-induced vasculotoxicity in arteries of different size and origin. Therefore, rats were treated with cyclosporin, 20 mg∙kg−1∙day−1, by gastric gavage for 10 days. In our previous studies, this treatment schedule induced renal functional impairment in vivo and an impaired relaxation response of thoracic aortic rings in vitro. Relaxation of various arteries (thoracic and abdominal aorta and carotid, renal, and interlobar arteries) from cyclosporin-treated and control rats in response to endothelium-dependent and -independent vasodilators was analysed. The thoracic aorta showed diminished endothelium-dependent and -independent relaxations; in the abdominal aorta no impairment was observed. Moreover, the dysfunction of the thoracic aorta seemed to be homogeneous along its length and showed an abrupt termination at the level of the diaphragm. In all other segments studied, no impairment of the relaxation responses was found. A similar pattern of vascular damage was found in rats treated with a very toxic cyclosporin treatment (50 mg∙kg−1∙day−1 s.c. × 7 days). The results indicate regional differences in cyclosporin-induced vasculotoxicity. The thoracic aorta, and in view of the fall of the renal blood flow, most likely also the renal resistance vessels, could be more susceptible than other vessels to cyclosporin-induced vascular dysfunction.Key words: cyclosporin, rat, arteries, vasorelaxation.

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Quantification of jet flow by momentum analysis. An in vitro color Doppler flow study.

Circulation ◽

10.1161/01.cir.81.1.247 ◽

1990 ◽

Vol 81 (1) ◽

pp. 247-259 ◽

Cited By ~ 113

Author(s):

J D Thomas ◽

C M Liu ◽

F A Flachskampf ◽

J P O'Shea ◽

R Davidoff ◽

...

Keyword(s):

Color Doppler ◽

Jet Flow ◽

Doppler Flow ◽

Color Doppler Flow ◽

Flow Study

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Loss of TIMP4 (Tissue Inhibitor of Metalloproteinase 4) Promotes Atherosclerotic Plaque Deposition in the Abdominal Aorta Despite Suppressed Plasma Cholesterol Levels

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.120.315522 ◽

2021 ◽

Author(s):

Mei Hu ◽

Sayantan Jana ◽

Tolga Kilic ◽

Faqi Wang ◽

Mengcheng Shen ◽

...

Keyword(s):

Extracellular Matrix ◽

Thoracic Aorta ◽

Abdominal Aorta ◽

Plasma Cholesterol ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Low Density ◽

Plaque Deposition ◽

Cholesterol Levels

Objective: Atherosclerosis is accumulation of lipids and extracellular matrix in the arterial wall. TIMPs (tissue inhibitor of metalloproteinases) can impact plaque deposition by regulating ECM (extracellular matrix) turnover. TIMP4 also influences lipid metabolism and smooth muscle cell (SMC) proliferation. We investigated the role of TIMP4 in atherosclerosis. Approach and Results: Mice lacking low-density lipoprotein receptor ( Ldlr −/− ) and Timp4 ( Timp4 −/− / Ldlr −/− ) were fed high-fat diet (HFD) or regular laboratory diet. After 3 or 6 months, HFD-fed male and female Timp4 −/− / Ldlr −/− mice exhibited higher plaque density in the abdominal aorta (but not in aortic valves, arch, thoracic aorta) compared with Ldlr −/− mice. Although plasma lipid and cholesterol levels were lower in Timp4 −/− / Ldlr −/− -HFD, cholesterol content in the abdominal aorta was higher along with elevated inflammatory cytokines, MMP (matrix metalloproteinase) activities, CD68 + /calponin + macrophage-like SMCs in Timp4 −/− / Ldlr −/− -HFD compared with Ldlr −/− -HFD mice. In vitro, oxidized LDL (low-density lipoprotein) markedly increased CD68 expression, reduced SMC markers, increased lipid uptake, and reduced cholesterol efflux protein ABCA1 (ATP-binding cassette transporter A1) in Timp4 −/− / Ldlr −/− compared with Ldlr −/− primary SMCs from abdominal, but not thoracic aorta. TIMP4 expression in the abdominal aorta (in vivo) and its corresponding SMCs (in vitro) was ≈2-fold higher than in the thoracic aorta and SMCs; TIMP4 levels decreased following HFD. Timp4 -deficiency in bone marrow–derived macrophages did not alter their foam cell formation capacity. Conclusions: TIMP4 protects against plaque deposition in the abdominal aorta independent of plasma cholesterol levels. TIMP4 prevents proteolytic degradation of ABCA1 in SMCs, hindering cholesterol accumulation and transdifferentiation to macrophage-like foam cells, representing a novel negative regulator of atherosclerosis.

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Arterial pulse wave propagation across stenoses and aneurysms: assessment of one-dimensional simulations against three-dimensional simulations and in vitro measurements

Journal of The Royal Society Interface ◽

10.1098/rsif.2020.0881 ◽

2021 ◽

Vol 18 (177) ◽

Author(s):

Weiwei Jin ◽

Jordi Alastruey

Keyword(s):

Abdominal Aorta ◽

Three Dimensional ◽

Experimental Models ◽

Arterial Blood Flow ◽

Future Research ◽

One Dimensional ◽

Arterial Blood ◽

Mean Square Errors ◽

Pressure And Flow Waves

One-dimensional (1-D) arterial blood flow modelling was tested in a series of idealized vascular geometries representing the abdominal aorta, common carotid and iliac arteries with different sizes of stenoses and/or aneurysms. Three-dimensional (3-D) modelling and in vitro measurements were used as ground truth to assess the accuracy of 1-D model pressure and flow waves. The 1-D and 3-D formulations shared identical boundary conditions and had equivalent vascular geometries and material properties. The parameters of an experimental set-up of the abdominal aorta for different aneurysm sizes were matched in corresponding 1-D models. Results show the ability of 1-D modelling to capture the main features of pressure and flow waves, pressure drop across the stenoses and energy dissipation across aneurysms observed in the 3-D and experimental models. Under physiological Reynolds numbers ( Re ), root mean square errors were smaller than 5.4% for pressure and 7.3% for the flow, for stenosis and aneurysm sizes of up to 85% and 400%, respectively. Relative errors increased with the increasing stenosis and aneurysm size, aneurysm length and Re , and decreasing stenosis length. All data generated in this study are freely available and provide a valuable resource for future research.

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Consumption of oxygen by thoracic and abdominal aorta of the rat

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1963.205.6.1200 ◽

1963 ◽

Vol 205 (6) ◽

pp. 1200-1202 ◽

Cited By ~ 7

Author(s):

Robert E. Priest

Keyword(s):

Nitrogen Content ◽

Thoracic Aorta ◽

Abdominal Aorta ◽

Deoxyribonucleic Acid ◽

Unit Weight ◽

Liver And Kidney ◽

The Difference ◽

Thoracic And Abdominal ◽

Low Nitrogen

Consumption of oxygen in vitro by thoracic and abdominal aorta and of liver and kidney of rats was measured by direct Warburg manometry and related to the weight of tissue and to the content of nitrogen and of deoxyribonucleic acid (DNA). On the basis of numbers of cells present, as determined by the content of DNA, thoracic aorta respires at a rate one-fifth that of liver. Thoracic aorta respires more actively than abdominal aorta but also contains more nitrogen and more DNA per unit weight than abdominal aorta. The difference in consumption of oxygen between these two segments of aorta can be explained largely, although not entirely, on the basis of numbers of cells present. Because of the lesser content of nitrogen and DNA in abdominal aorta, it must contain larger amounts of some substance which contributes to weight and has a low nitrogen content.

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