A cone-plate apparatus for the in vitro biochemical and molecular analysis of the effect of shear stress on adherent cells

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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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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Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model

Antibiotics ◽

10.3390/antibiotics10080886 ◽

2021 ◽

Vol 10 (8) ◽

pp. 886

Author(s):

Youngbeom Ahn ◽

Ji Young Jung ◽

Ohgew Kweon ◽

Brian T. Veach ◽

Sangeeta Khare ◽

...

Keyword(s):

Molecular Analysis ◽

Intestinal Microbiota ◽

Continuous Flow ◽

Antimicrobial Drug ◽

Bioreactor Culture ◽

Analysis Techniques ◽

Human Intestinal Microbiota ◽

Traditional Cultures ◽

The Impact

Studying potential dietary exposure to antimicrobial drug residues via meat and dairy products is essential to ensure human health and consumer safety. When studying how antimicrobial residues in food impact the development of antimicrobial drug resistance and disrupt normal bacteria community structure in the intestine, there are diverse methodological challenges to overcome. In this study, traditional cultures and molecular analysis techniques were used to determine the effects of tetracycline at chronic subinhibitory exposure levels on human intestinal microbiota using an in vitro continuous flow bioreactor. Six bioreactor culture vessels containing human fecal suspensions were maintained at 37 °C for 7 days. After a steady state was achieved, the suspensions were dosed with 0, 0.015, 0.15, 1.5, 15, or 150 µg/mL tetracycline, respectively. Exposure to 150 µg/mL tetracycline resulted in a decrease of total anaerobic bacteria from 1.9 × 107 ± 0.3 × 107 down to 2 × 106 ± 0.8 × 106 CFU/mL. Dose-dependent effects of tetracycline were noted for perturbations of tetB and tetD gene expression and changes in acetate and propionate concentrations. Although no-observed-adverse-effect concentrations differed, depending on the traditional cultures and the molecular analysis techniques used, this in vitro continuous flow bioreactor study contributes to the knowledge base regarding the impact of chronic exposure of tetracycline on human intestinal microbiota.

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Mechanical Strain-Enabled Reconstitution of Dynamic Environment in Organ-on-a-Chip Platforms: A Review

Micromachines ◽

10.3390/mi12070765 ◽

2021 ◽

Vol 12 (7) ◽

pp. 765

Author(s):

Qianbin Zhao ◽

Tim Cole ◽

Yuxin Zhang ◽

Shi-Yang Tang

Keyword(s):

Cell Culture ◽

Shear Stress ◽

Cultured Cells ◽

Mechanical Strain ◽

3D Cell Culture ◽

Small Scale ◽

Mechanical Stimuli ◽

Human Organ ◽

Organ On A Chip

Organ-on-a-chip (OOC) uses the microfluidic 3D cell culture principle to reproduce organ- or tissue-level functionality at a small scale instead of replicating the entire human organ. This provides an alternative to animal models for drug development and environmental toxicology screening. In addition to the biomimetic 3D microarchitecture and cell–cell interactions, it has been demonstrated that mechanical stimuli such as shear stress and mechanical strain significantly influence cell behavior and their response to pharmaceuticals. Microfluidics is capable of precisely manipulating the fluid of a microenvironment within a 3D cell culture platform. As a result, many OOC prototypes leverage microfluidic technology to reproduce the mechanically dynamic microenvironment on-chip and achieve enhanced in vitro functional organ models. Unlike shear stress that can be readily generated and precisely controlled using commercial pumping systems, dynamic systems for generating proper levels of mechanical strains are more complicated, and often require miniaturization and specialized designs. As such, this review proposes to summarize innovative microfluidic OOC platforms utilizing mechanical actuators that induce deflection of cultured cells/tissues for replicating the dynamic microenvironment of human organs.

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In Vitro Assay for Single-cell Characterization of Impaired Deformability in Red Blood Cells under Recurrent Episodes of Hypoxia

Lab on a Chip ◽

10.1039/d1lc00598g ◽

2021 ◽

Author(s):

YUHAO QIANG ◽

Jia Liu ◽

Ming Dao ◽

E Du

Keyword(s):

Shear Stress ◽

Red Blood Cells ◽

Single Cell ◽

Blood Cells ◽

Blood Circulation ◽

In Vitro Assay ◽

Vitro Assay ◽

Cyclic Shear

Red blood cells (RBCs) are subjected to recurrent changes in shear stress and oxygen tension during blood circulation. The cyclic shear stress has been identified as an important factor that...

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POS0330 NINTEDANIB (TYROSINE KINASE INHIBITOR) DOWNREGULATES THE TRANSITION OF CULTURED SYSTEMIC SCLEROSIS FIBROCYTES INTO MYOFIBROBLASTS AND THEIR PRO-FIBROTIC ACTIVITY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2411 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 392.2-392

Author(s):

S. Soldano ◽

P. Montagna ◽

E. Gotelli ◽

S. Tardito ◽

S. Paolino ◽

...

Keyword(s):

Gene Expression ◽

Systemic Sclerosis ◽

Tyrosine Kinase ◽

Tyrosine Kinase Inhibitor ◽

Kinase Inhibitor ◽

Adherent Cells ◽

Research Support ◽

Fibrotic Process ◽

Circulating Fibrocytes

Background:Fibroblast-to-myofibroblast transition is one of the fundamental steps involved in the fibrotic process that characterise systemic sclerosis (SSc) [1]. Myofibroblasts are α-smooth muscle actin (αSMA) positive cells that contribute to fibrosis through the excessive synthesis and deposition of extracellular matrix (ECM) proteins, primarily fibronectin (FN) and type I collagen (COL1) [2].Among the cells involved in the fibrotic process of SSc, circulating fibrocytes seem to have an emerging role as an important source of fibroblasts and myofibroblasts [3].Nintedanib is a tyrosine kinase inhibitor approved for the treatment of idiopathic pulmonary fibrosis that interferes with the signalling pathways involved in the pathogenesis of fibrosis (4). Nintedanib was recently demonstrated to have a beneficial effect in patients with interstitial lung disease (ILD) associated with SSc (5).Objectives:To investigate nintedanib effect in inhibiting the in vitro transition of circulating SSc fibrocytes into myofibroblasts and their pro-fibrotic activity.Methods:Circulating fibrocytes were obtained from 14 SSc patients (mean age 64±14 years), who fulfilled the 2013 ACR/EULAR criteria for SSc and that underwent complete disease staging in a day-hospital setting at the Rheumatology Division of Genoa University. Five age-matched healthy subjects (HSs) were also analysed. All SSc patients and HSs signed the informed consent and the local EC approved the study. Peripheral blood mononuclear cells were isolated by density gradient centrifugation and plated on FN-coated dishes. After overnight culture, non-adherent cells were removed, and adherent cells were maintained in growth medium for 8 days (T8) to obtain fibrocytes [6]. T8-cultured SSc fibrocytes were maintained in growth medium (untreated cells) or treated with nintedanib 0.1μM and 1μM for 3 and 24 hours. Fibroblast specific protein-1 (S100A4) and αSMA, as markers of fibroblast/myofibroblast phenotype, together with COL1 and FN, were investigated by qRT-PCR and Western blotting. Non-parametric Mann-Whitney and Wilcoxon tests were used for the statistical analysis.Results:Significantly elevated gene and protein expressions of αSMA, S100A4, COL1 and FN were observed in SSc fibrocytes compared to HS fibrocytes (gene: αSMA p<0.001; others p<0.0001; protein: all p<0.05). In accordance with the antibody positivity for Scl70 and the presence or absence of ILD at CT scan, SSc patients were grouped as either Scl70 positive patients with ILD (Scl70+ILD+) or Scl70 negative patients without ILD (Scl70-ILD-). Significant αSMA, S100A4, COL1 and FN gene expressions were found in fibrocytes from Scl70+ILD+ compared to HS fibrocytes (αSMA p<0.001; others p<0.0001). Moreover, fibrocytes from Scl70+ILD+patients showed a more significant gene expression of fibroblasts/myofibroblasts markers compared to Scl70-ILD-patients (p<0.01 for S100A4), whereas no differences were observed for ECM gene expression.Nintedanib reduced the gene and protein expression of αSMA, COL1 and FN in SSc fibrocytes compared to untreated ones with different statistical significance.Noteworthy, nintedanib significantly downregulated αSMA, S100A4, COL1 and FN gene expression (all p<0.05) in Scl70+ILD+fibrocytes, whereas only that of S100A4 and FN was significantly downregulated (p<0.05) in Scl70-ILD- fibrocytes compared to untreated cells.Conclusion:Nintedanib seems to downregulate in vitro the transition of fibrocytes into myofibroblasts and their pro-fibrotic activity, particularly in cells isolated from Scl70+ILD+SSc patients.References:[1]Cutolo M et al. Exp Rev Clin Immunol. 2019;15:753-64.[2]Van Caam A et al. Front. Immunol. 2018;9:2452.doi:10.3389/fimmu.2018.02452.[3]Distler JH et al. Arthritis Rheumatol. 2017;69:257-67.[4]Distler O et al. New Eng J Med. 2019; 380:2518-28.[5]Maher TB et al. Arthritis Rheumatol.2020.doi:10.1002/art.41576.[6]Cutolo M et al. Arthritis Res Ther. 2018;20:157.doi:10.1186/s13075-018-1652-6.Acknowledgements:We thank Stefano-Lutz Willing for the scientific support through the study.Disclosure of Interests:Stefano Soldano: None declared, Paola Montagna: None declared, Emanuele Gotelli: None declared, Samuele Tardito: None declared, Sabrina Paolino: None declared, Claudio Corallo: None declared, Carmen Pizzorni: None declared, Alberto Sulli: None declared, Carlotta Schenone: None declared, Greta Pacini: None declared, Vanessa Smith: None declared, Maurizio Cutolo Grant/research support from: I received grant/research support from Bristol-Myers Squibb, Boehringer, Celgene

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