A new in vitro perfusion test system for leukocyte migration studies under shear stress effects of thiopentone and propofol

SummaryAlterations in platelet aggregability may play a role in the pathogenesis of qualitative platelet defects associated with cardiopulmonary bypass (CPB). We circulated fresh heparinized whole blood through tubing sets coated with heparin (C group, n = 10) and through non-coated sets (N group, n = 10) as a simulated CPB circuit. Shear stress (108 dyne/cm2)-induced platelet aggregation (hSIPA), plasma von Willebrand factor (vWF) activity and platelet glycoprotein (GP) Ib expression were measured, before, during, and after this in vitro set up of circulation. In the two groups, the extent of hSIPA significantly decreased during circulation and was partially restored after circulation. Decreases in the extent of hSIPA were significantly less with use of heparin-coated circuits. There was an equivalent reduction in plasma vWF activity, in the two groups. Expression of platelet surface GP Ib decreased significantly during circulation and recovered after circulation. Reduction of surface GP Ib expression during circulation was significantly less in the C group than that in the N group. Decrease in surface GP Ib expression correlated (r = 0.88 in either group) with the magnitude of hSIPA, in the two groups. The progressive removal of surface GP Ib was mainly attributed to redistribution of GP Ib from the membrane skeleton into the cytoskeleton. Our observations suggest that use of heparin-coated circuits partly blocks the reduction of hSIPA, as a result of a lesser degree of redistribution of GP Ib.

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The Effect of Heparin vs. Citrate on the Interaction of Platelets with Vascular Graft Materials

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660145 ◽

1985 ◽

Vol 54 (04) ◽

pp. 842-848 ◽

Cited By ~ 14

Author(s):

Kandice Kottke-Marchant ◽

James M Anderson ◽

Albert Rabinovitch ◽

Richard A Huskey ◽

Roger Herzig

Keyword(s):

Platelet Aggregation ◽

Platelet Activation ◽

Vascular Graft ◽

Time Course ◽

Platelet Reactivity ◽

Polymer Surfaces ◽

In Vitro Perfusion ◽

Citrate Anticoagulation ◽

Platelet Release

SummaryHeparin is known to affect platelet function in vitro, but little is known about the effect of heparin on the interaction of platelets with polymer surfaces in general, and vascular graft materials in particular. For this reason, the effect of heparin vs. citrate anticoagulation on the interaction of platelets with the vascular graft materials expanded polytetrafluoroethylene (ePTFE), Dacron Bionit (DB) and preclotted Dacron Bionit (DB/PC) was studied in a recirculating, in vitro perfusion system. Platelet activation, as shown by a decrease in platelet count, an increase in platelet release and a decrease in platelet aggregation, was observed for all vascular graft materials tested using heparin and was greater for Dacron and preclotted Dacron than for ePTFE. Significant differences between heparin and citrate anticoagulation were seen for platelet release, platelet aggregation and the relative ranking of material platelet-reactivity. However, the trends and time course of platelet activation were similar with both heparin and citrate for the materials tested.

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Der Effekt von Hypoxie auf die plazentare Leptinsynthese in der dualen in-vitro Perfusion humaner Plazenten

Zeitschrift für Geburtshilfe und Neonatologie ◽

10.1055/s-2003-818188 ◽

2004 ◽

Vol 207 (S 2) ◽

Author(s):

S Kuno ◽

K May ◽

R Trollmann ◽

J Dötsch ◽

N Siebert ◽

...

Keyword(s):

In Vitro Perfusion

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Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1984.247.3.g305 ◽

1984 ◽

Vol 247 (3) ◽

pp. G305-G310

Author(s):

W. J. Kortz ◽

J. R. Nashold ◽

M. R. Greenfield ◽

H. Hilderman ◽

S. H. Quarfordt

Keyword(s):

Fatty Acid ◽

Free Fatty Acid ◽

Fatty Acyl ◽

Liver Fat ◽

Molar Ratio ◽

Perfusion System ◽

In Vitro Perfusion ◽

Arterial Inflow ◽

High Concentrations

The metabolism of double-labeled triglyceride in a synthetic emulsion was defined in an in vitro perfusion system of rat hind end and liver described previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8): G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined in the absence of added apoproteins and with additions of human CII and both CII and CIII. Without apoprotein, a pronounced lipolysis of the triglyceride was recognized by high concentrations of radiolabeled glycerol and free fatty acid in the perfusate. The removal of an aliquot of hind-end venous effluent 5 min after adding the labeled triglyceride emulsion to the arterial inflow demonstrated a brisk lipolysis of the substrate when incubated outside the perfusion system. The addition of CII protein to the emulsion before its introduction into the tandem system eliminated perfusate lipolysis, both within the perfusion system and in incubations of aliquots withdrawn from the system. Intravascular lipolysis was not seen with triglyceride emulsions containing both CII and CIH or when an aliquot of hind-end venous effluent was incubated with triglycerides that had not been exposed to the perfusion system. The intravascular lipolysis observed for the [14C]triglyceride added to the tandem system without apoproteins was associated with relatively greater recoveries of 14C-fatty acyl in liver, fat, and muscle and relatively greater recoveries of 14CO2 than when CII alone or both CII and CIII were added with the triglyceride. The addition of CIII to CII in a 1:1 molar ratio increased the recovery of 14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

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Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

Scientific Reports ◽

10.1038/s41598-021-93935-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Semra Zuhal Birol ◽

Rana Fucucuoglu ◽

Sertac Cadirci ◽

Ayca Sayi-Yazgan ◽

Levent Trabzon

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Vascular System ◽

Circulatory System ◽

Disease Process ◽

Microfluidic Channels ◽

Shear Stresses ◽

Stress Effects ◽

Adhesion Behavior ◽

Cycling System

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

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Platelet membrane-coated nanoparticles target sclerotic aortic valves in ApoE−/− mice by multiple binding mechanisms under pathological shear stress

European Heart Journal ◽

10.1093/ehjci/ehaa946.1863 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

H Yang ◽

Y Song ◽

Z Huang ◽

J Qian ◽

Z Pang ◽

...

Keyword(s):

Shear Stress ◽

Aortic Valve ◽

Aortic Valve Disease ◽

Binding Capacity ◽

Platelet Membrane ◽

Valve Disease ◽

Funding Source ◽

Aortic Valves ◽

Coated Nanoparticles

Abstract Background Aortic valve disease is the most common valvular heart disease leading to valve replacement. The efficacy of pharmacological therapy for aortic valve disease is limited by the high mechanical stress at the aortic valves impairing the binding rate. We aimed to identify nanoparticle coating with entire platelet membranes to fully mimic their inherent multiple adhesion mechanisms and target the sclerotic aortic valve of apolipoprotein E-deficient (ApoE−/−) mice based on their multiple sites binding capacity under high shear stress. Methods Considering the potent interaction of platelet membrane glycoproteins with components present in sclerotic aortic valves, platelet membrane-coated nanoparticles (PNPs) were synthetized and the binding capacity under high shear stress was evaluated in vitro and in vivo. Results Compared with PNPs bound intensity in the static station, 161%, 59%, and 39% of attached PNPs remained adherent on VWF-, collagen-, and fibrin-coated surfaces under shear stress of 25dyn/cm2 respectively. PNPs demonstrated effectively adhering to von Willebrand factor, collagen and fibrin under shear stresses in vitro. In an aortic valve disease model established in ApoE−/− mice, PNPs group exhibited significant increase of accumulation in the aortic valves compared with PBS and control NP group. PNPs displayed high degrees of proximity or co-localization with vWF, collagen and fibrin, which exhibited good targeting to sclerotic aortic valves by mimicking platelet multiple adhesive mechanisms. Conclusion PNPs could provide a promising platform for the molecular diagnosis and targeting treatment of aortic valve disease. Targeting combination Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): National Natural Science Foundation of China

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Investigation of Wall Shear Stress in Cardiovascular Research and in Clinical Practice—From Bench to Bedside

International Journal of Molecular Sciences ◽

10.3390/ijms22115635 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5635

Author(s):

Katharina Urschel ◽

Miyuki Tauchi ◽

Stephan Achenbach ◽

Barbara Dietel

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Wall Shear Stress ◽

Cell Function ◽

Computational Techniques ◽

Apical Surface ◽

Cardiovascular Research ◽

Endothelial Cell Function ◽

Wall Shear

In the 1900s, researchers established animal models experimentally to induce atherosclerosis by feeding them with a cholesterol-rich diet. It is now accepted that high circulating cholesterol is one of the main causes of atherosclerosis; however, plaque localization cannot be explained solely by hyperlipidemia. A tremendous amount of studies has demonstrated that hemodynamic forces modify endothelial athero-susceptibility phenotypes. Endothelial cells possess mechanosensors on the apical surface to detect a blood stream-induced force on the vessel wall, known as “wall shear stress (WSS)”, and induce cellular and molecular responses. Investigations to elucidate the mechanisms of this process are on-going: on the one hand, hemodynamics in complex vessel systems have been described in detail, owing to the recent progress in imaging and computational techniques. On the other hand, investigations using unique in vitro chamber systems with various flow applications have enhanced the understanding of WSS-induced changes in endothelial cell function and the involvement of the glycocalyx, the apical surface layer of endothelial cells, in this process. In the clinical setting, attempts have been made to measure WSS and/or glycocalyx degradation non-invasively, for the purpose of their diagnostic utilization. An increasing body of evidence shows that WSS, as well as serum glycocalyx components, can serve as a predicting factor for atherosclerosis development and, most importantly, for the rupture of plaques in patients with high risk of coronary heart disease.

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

Micromachines ◽

10.3390/mi12030346 ◽

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.

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Role of Phase II Enzymes in the Bioactivation of 1,4-Dichlorobenzene and 1,4-Dibromobenzene

Alternatives to Laboratory Animals ◽

10.1177/026119299602400422 ◽

1996 ◽

Vol 24 (4) ◽

pp. 603-608

Author(s):

Moreno Paolini ◽

Laura Pozzetti ◽

Renata Mesirca ◽

Andrea Sapone ◽

Paola Silingardi ◽

...

Keyword(s):

Dna Binding ◽

Phase I ◽

Phase Ii ◽

Covalent Binding ◽

Fold Increase ◽

Test System ◽

Oxidative Enzymes ◽

Transferase Activity ◽

Genetic Toxicology

The use of sodium phenobarbital (PB, CYP2B1 inducer) combined with β-naphthoflavone (β-NF, 1A1) to induce certain Phase I reactions in S9 liver fractions is a standard method for conducting short-term bioassays for genotoxicity. However, because post-oxidative enzymes are also able to activate many precarcinogens, we tested the possibility of adapting S9 liver fractions derived from Phase II-induced rodents to the field of genetic toxicology. In this study, S9 liver fractions derived from Swiss albino CD1 mice fed 7.5g/kg 2-(3)-tert-butyl-4-hydroxyanisole (BHA; a monofunctional Phase II-inducer) for 3 weeks, show a clear pattern of induction with an approximately 3.5–9.5-fold increase in glutathione S-transferase activity. In vitro DNA binding of the promutagenic agents, [14C]-l,4-dichlorobenzene (DCB) and [14C]-1,4-dibromobenzene (DBB), is mediated by such metabolic liver preparations and showed a significant increase in covalent binding capability. In some instances, enzyme activity was more elevated when compared to that obtained with traditional (Phase I-induced) S9. Together with DNA binding, the genetic response of these chemicals in the diploid D7 strain of Saccharomyces cerevisiae used as a biological test system, revealed the ability of the BHA-derived preparations to activate the promutagenic agents, as exemplified by the significant enhancement of mitotic gene-conversion (up to 5.2-fold for DCB and 3.4-fold for DBB) and reverse point mutation (up to 3.6-fold for DCB and 2.5-fold for DBB) at a 4mM concentration. This novel metabolising biosystem, with enhanced Phase II activity, is recommended together with a traditional S9, for detecting unknown promutagens in genotoxicity studies. The routine use of either oxidative or post-oxidative S9 increases the responsiveness of the test and can contribute to the identification of promutagens not detected when using traditional protocols.

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