scholarly journals The Effect of Microfluidic Geometry on Myoblast Migration

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 143
Author(s):  
Rahul Atmaramani ◽  
Bryan Black ◽  
Kevin Lam ◽  
Vinit Sheth ◽  
Joseph Pancrazio ◽  
...  
Keyword(s):  
Cell Migration ◽  
Microfluidic Devices ◽  
In Vitro Studies ◽  
Future Design ◽  
The Future ◽  
Pdms Microchannel ◽  
In Vitro Systems ◽  
Spontaneous Migration ◽  
Over Time

In vitro systems comprised of wells interconnected by microchannels have emerged as a platform for the study of cell migration or multicellular models. In the present study, we systematically evaluated the effect of microchannel width on spontaneous myoblast migration across these microchannels—from the proximal to the distal chamber. Myoblast migration was examined in microfluidic devices with varying microchannel widths of 1.5–20 µm, and in chips with uniform microchannel widths over time spans that are relevant for myoblast-to-myofiber differentiation in vitro. We found that the likelihood of spontaneous myoblast migration was microchannel width dependent and that a width of 3 µm was necessary to limit spontaneous migration below 5% of cells in the seeded well after 48 h. These results inform the future design of Polydimethylsiloxane (PDMS) microchannel-based co-culture platforms as well as future in vitro studies of myoblast migration.

scholarly journals Developmental Neurotoxicity of Fipronil and Rotenone on a Human Neuronal In Vitro Test System

2021 ◽  
Author(s):  
Anne Schmitz ◽  
Silke Dempewolf ◽  
Saime Tan ◽  
Gerd Bicker ◽  
Michael Stern
Keyword(s):  
Cell Migration ◽  
Neurite Outgrowth ◽  
Neuronal Differentiation ◽  
Precursor Cell ◽  
Developmental Neurotoxicity ◽  
In Vitro Studies ◽  
Human Model ◽  
In Vitro Test ◽  
Dependent Manner

AbstractPesticide exposure during in utero and early postnatal development can cause a wide range of neurological defects. However, relatively few insecticides have been recognized as developmental neurotoxicants, so far. Recently, discovery of the insecticide, fipronil, in chicken eggs has raised public concern. The status of fipronil as a potential developmental neurotoxicant is still under debate. Whereas several in vivo and in vitro studies suggest specific toxicity, other in vitro studies could not confirm this concern. Here, we tested fipronil and its main metabolic product, fipronil sulfone both at concentrations between 1.98 and 62.5 µM, alongside with the established developmental neurotoxicant, rotenone (0.004–10 µM) in vitro on the human neuronal precursor cell line NT2. We found that rotenone impaired all three tested DNT endpoints, neurite outgrowth, neuronal differentiation, and precursor cell migration in a dose-dependent manner and clearly separable from general cytotoxicity in the nanomolar range. Fipronil and fipronil sulfone specifically inhibited cell migration and neuronal differentiation, but not neurite outgrowth in the micromolar range. The rho-kinase inhibitor Y-27632 counteracted inhibition of migration for all three compounds (EC50 between 12 and 50 µM). The antioxidant, n-acetyl cysteine, could ameliorate the inhibitory effects of fipronil on all three tested endpoints (EC 50 between 84 and 164 µM), indicating the involvement of oxidative stress. Fipronil sulfone had a stronger effect than fipronil, confirming the importance to test metabolic products alongside original pesticides. We conclude that in vitro fipronil and fipronil sulfone display specific developmental neurotoxicity on developing human model neurons.

scholarly journals Engineering Silicone Rubbers for In Vitro Studies: Creating AAA Models and ILT Analogues With Physiological Properties

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
T. J. Corbett ◽  
B. J. Doyle ◽  
A. Callanan ◽  
M. T. Walsh ◽  
T. M. McGloughlin
Keyword(s):  
In Vitro Studies ◽  
In Vivo Studies ◽  
Aortic Tissue ◽  
Element Analysis ◽  
Future Design ◽  
Change Behavior ◽  
Physiological Properties ◽  
Diameter Change

In vitro studies of abdominal aortic aneurysm (AAA) have been widely reported. Frequently mock artery models with intraluminal thrombus (ILT) analogs are used to mimic the in vivo AAA. While the models used may be physiological, their properties are frequently either not reported or investigated. This study is concerned with the testing and characterization of previously used vessel analog materials and the development of new materials for the manufacture of AAA models. These materials were used in conjunction with a previously validated injection molding technique to manufacture AAA models of ideal geometry. To determine the model properties (stiffness (β) and compliance), the diameter change of each AAA model was investigated under incrementally increasing internal pressures and compared with published in vivo studies to determine if the models behaved physiologically. A FEA study was implemented to determine if the pressure-diameter change behavior of the models could be predicted numerically. ILT analogs were also manufactured and characterized. Ideal models were manufactured with ILT analog internal to the aneurysm region, and the effect of the ILT analog on the model compliance and stiffness was investigated. The wall materials had similar properties (Einit 2.22 MPa and 1.57 MPa) to aortic tissue at physiological pressures (1.8 MPa (from literature)). ILT analogs had a similar Young’s modulus (0.24 MPa and 0.33 MPa) to the medial layer of ILT (0.28 MPa (from literature)). All models had aneurysm sac compliance (2.62–8.01×10−4/mm Hg) in the physiological range (1.8–9.4×10−4/mm Hg (from literature)). The necks of the AAA models had similar stiffness (20.44–29.83) to healthy aortas (17.5±5.5 (from literature)). Good agreement was seen between the diameter changes due to pressurization in the experimental and FEA wall models with a maximum difference of 7.3% at 120 mm Hg. It was also determined that the inclusion of ILT analog in the sac of the models could have an effect on the compliance of the model neck. Ideal AAA models with physiological properties were manufactured. The behavior of these models due to pressurization was predicted using finite element analysis, validating this technique for the future design of realistic physiological AAA models. Addition of ILT analogs in the aneurysm sac was shown to affect neck behavior. This could have implications for endovascular AAA repair due to the importance of the neck for stent-graft fixation.

Decreased marine dimethyl sulfide production under elevated CO2 levels in mesocosm and in vitro studies

2012 ◽  
Vol 9 (4) ◽  
pp. 399 ◽  
Author(s):  
Valia Avgoustidi ◽  
Philip D. Nightingale ◽  
Ian Joint ◽  
Michael Steinke ◽  
Suzanne M. Turner ◽  
...  
Keyword(s):  
Human Activities ◽  
Dimethyl Sulfide ◽  
Marine Organisms ◽  
In Vitro Studies ◽  
Structural Components ◽  
Seawater Ph ◽  
Co2 Levels ◽  
The Future ◽  
Climate Cooling

Environmental contextAs atmospheric CO2 levels rise due to human activities, more of the gas dissolves in the oceans, increasing their acidity. The effect of these seawater changes on marine organisms is largely unknown. We examine the consequences of higher CO2 levels on the production by plankton of dimethyl sulfide, a climatically active gas. We find that higher CO2 levels leads to lower concentrations of dimethyl sulfide in the seawater, which has potentially important implications for the future climate. AbstractThe oceans have absorbed approximately half of the CO2 produced by human activities and it is inevitable that surface seawaters will become increasingly acidified. The effect of lower pH on marine organisms and ocean–atmosphere exchanges is largely unknown but organisms with CaCO3 structural components are likely to be particularly affected. Because calcifying phytoplankton are significant producers of dimethyl sulfide (DMS), it is vital to understand how lower seawater pH may affect DMS production and emission to the atmosphere. Here we show, by mesocosm (Raunefjorden, Norway, April–May 2003) and in vitro studies, that the net production of DMS and its cellular precursor dimethylsulfoniopropionate (DMSP) is approximately halved in microbial communities subjected to doubled CO2 levels. Our findings provide evidence that the amount of DMS entering the atmosphere could decrease in the future. Because atmospheric oxidation of DMS can lead to climate cooling by increasing cloud albedo, a consequence of reduced DMS emissions from a lower pH ocean would be an enhancement in global warming.

scholarly journals Mechanisms Involved in the Pathogenesis of Sepsis Are Not Necessarily Reflected by In Vitro Cell Activation Studies

1998 ◽  
Vol 66 (11) ◽  
pp. 5372-5378 ◽  
Author(s):  
Claudia R. Amura ◽  
R. Silverstein ◽  
D. C. Morrison
Keyword(s):  
Cell Activation ◽  
Endotoxic Shock ◽  
Peritoneal Macrophages ◽  
In Vitro Studies ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
In Vitro Systems ◽  
A Cell

ABSTRACT It is thought that lipopolysaccharide (LPS) from gram-negative bacteria contributes significantly to the pathogenesis of septic shock. In vitro studies to address the mechanisms involved in this process have often investigated human monocytes or mouse macrophages, since these cells produce many of the mediators found in septic patients. Targeting of these mediators, especially tumor necrosis factor alpha (TNF-α), has been pursued as a means of reducing mortality in sepsis. Two experimental approaches were designed to test the assumption that in vitro studies with macrophages accurately predict in vivo mechanisms of LPS pathogenesis. In the first approach, advantage was taken of the fact that on consecutive days after injection of thioglycolate into mice, increased numbers of macrophages could be harvested from the peritoneum. These cells manifested markedly enhanced levels of in vitro TNF-α, interleukin 6 (IL-6), and nitric oxide production in response to LPS. In d-galactosamine-sensitized mice, however, thioglycolate treatment significantly decreased mortality due to LPS, as well as levels of circulating TNF-α and IL-6. Anti-TNF-α treatment confirmed this cytokine’s role in the observed lethality. In a second experimental approach, we compared the mouse macrophage-stimulating potencies of different LPS preparations with their lethalities to mice. In these studies, the in vitro macrophage-stimulating profiles presented by rough-LPS and smooth-LPS preparations were the reverse of their relative lethal potencies in vivo. In conclusion, peritoneal macrophages appear not to be the major cells responsible for the overall host response during endotoxic shock. These findings underscore the importance of verifying the correlation of in vivo systems with in vitro systems when attributing specific functions to a cell type.

Regulatory requirements for in vitro systems to meet performance standards during validation and over time

2009 ◽  
Vol 189 ◽  
pp. S272-S273
Author(s):  
Mitch Klausner ◽  
Joseph Kubilus ◽  
Seyoum Ayehunie ◽  
Yulia Kaluzhny ◽  
Helena Kandarova ◽  
...  
Keyword(s):  
Performance Standards ◽  
Regulatory Requirements ◽  
In Vitro Systems ◽  
Over Time

scholarly journals In vitro formation of neuroclusters in microfluidic devices and cell migration as a function of stromal-derived growth factor 1 gradients

2016 ◽  
Vol 11 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Sean McCutcheon ◽  
Uchenna Unachukwu ◽  
Ankush Thakur ◽  
Robert Majeska ◽  
Stephen Redenti ◽  
...  
Keyword(s):  
Cell Migration ◽  
Growth Factor ◽  
Microfluidic Devices

The Role of Integrin αDβ2 in Macrophage Migration.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2215-2215
Author(s):  
Valentin P. Yakubenko ◽  
Tatiana P. Ugarova
Keyword(s):  
Extracellular Matrix ◽  
Cell Migration ◽  
Extracellular Matrix Proteins ◽  
In Vitro Studies ◽  
Matrix Proteins ◽  
Hek293 Cells ◽  
Macrophage Migration ◽  
Blocking Antibodies

Abstract Integrin αDβ2 (CD11d/CD18), the most recently discovered member of the β2 sub-family of adhesion receptors, is strongly upregulated on macrophage foam cells which underscores its potential role in atherosclerosis. However, the contribution of αDβ2 to monocyte/macrophage adhesive reactions and the significance of its overexpression on these cells remain unknown. Recently we characterized αDβ2 as a multiligand receptor capable of binding many extracellular matrix proteins with the recognition specificity overlapping that of the major myeloid-specific integrin αMβ2 (Mac-1). We hypothesized that the αDβ2 ability to bind numerous ligands in the extracellular matrix and its capacity to be upregulated to high density on the surface of macrophages may modulate cell adhesiveness and, thus, affect migration. To evaluate the role of αDβ2 in migration, we generated model and natural cells expressing different densities of αDβ2 and tested their migration to different extracellular matrix proteins. In vitro studies demonstrated that αDβ2 expressed at low densities, either on the surface of HEK293 cells or the mouse macrophage cell line IC-21, supported migration which was partially inhibited by anti-αD function-blocking antibodies. Furthermore, β1 and β3 integrins expressed on HEK293 cells and IC-21 macrophages, respectively, contributed to migration because anti-β1 and anti-β3 antibodies inhibited migration. Increased expression of αDβ2 on the surface of HEK293 cells and its upregulation by PMA on IC-21 macrophages resulted in the inhibition of cell migration. Ligation of αDβ2 with anti-αD antibodies restored β1- and β3-driven cell migration by means of removing restraints imposed by the excess of the αDβ2-ligand adhesive bonds. To test the possibility that progressive upregulation of αDβ2 can block macrophage migration in vivo, we assessed the effect of anti-αD function blocking antibodies using the thioglycollate-induced peritonitis model. More than 4-fold upregulation of αDβ2 was detected on macrophages in 72 h after thioglycollate stimulation and, similar to in vitro studies, the numbers of migration macrophages increased in the presence of anti-αD antibodies. These results demonstrate that the density of αDβ2 can modulate cell migration and suggest that low levels of αDβ2 can contribute to monocyte migration while αDβ2 upregulation on differentiated macrophages might facilitate their retention at the site of inflammation.

Microfluidic devices for in vitro studies on liver drug metabolism and toxicity

2011 ◽  
Vol 3 (5) ◽  
pp. 509 ◽  
Author(s):  
Paul M. van Midwoud ◽  
Elisabeth Verpoorte ◽  
Geny M. M. Groothuis
Keyword(s):  
Drug Metabolism ◽  
Microfluidic Devices ◽  
In Vitro Studies

scholarly journals Combinative in vitro studies and computational model to predict 3D cell migration response to drug insult

2014 ◽  
Vol 6 (10) ◽  
pp. 957-972 ◽  
Author(s):  
Joseph S. Maffei ◽  
Jaya Srivastava ◽  
Brian Fallica ◽  
Muhammad H. Zaman
Keyword(s):  
Cell Migration ◽  
Computational Model ◽  
In Vitro Studies ◽  
3D Cell Migration ◽  
Migration Response

scholarly journals The Enterovirus 71 Procapsid Binds Neutralizing Antibodies and Rescues Virus InfectionIn Vitro

2014 ◽  
Vol 89 (3) ◽  
pp. 1900-1908 ◽  
Author(s):  
Kristin L. Shingler ◽  
Javier O. Cifuente ◽  
Robert E. Ashley ◽  
Alexander M. Makhov ◽  
James F. Conway ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Infectious Virus ◽  
Enterovirus 71 ◽  
Asia Pacific ◽  
Future Design ◽  
Successful Infection ◽  
Empty Capsid ◽  
Antigenic Properties ◽  
The Future

ABSTRACTEnterovirus 71 (EV71) is responsible for seasonal outbreaks of hand, foot, and mouth disease in the Asia-Pacific region. The virus has the capability to cause severe disease and death, especially in young children. Although several vaccines are currently in clinical trials, no vaccines or therapeutics have been approved for use. Previous structural studies have revealed that two antigenically distinct capsid forms are produced in EV71-infected cells: an expanded empty capsid, sometimes called a procapsid, and the infectious virus. Specifically, an immunodominant epitope of EV71 that maps to the virus canyon is structurally different in the procapsid and virus. This structure-function study shows that the procapsid can sequester antibodies, thus enhancing EV71 infectionin vitro. The results presented here suggest that, due to conformational differences between the EV71 procapsid and virus, the presence of the procapsid in natural virus infections should be considered in the future design of vaccines or therapeutics.IMPORTANCEIn a picornavirus infection, both an infectious and a noninfectious empty capsid, sometimes referred to as a procapsid, are produced. It was novel to discover that the procapsid form of EV71 was expanded and antigenically distinct from the infectious virus. Previously, it had been supposed that this empty capsid was an off-pathway dead end or at best served for storage of pentameric subunits, which was later shown to be unlikely. It remains unexplained why picornaviruses evolutionarily conserve the wasteful production of so much noninfectious capsid. Here, we demonstrate that the EV71 procapsid has different antigenic properties than the infectious virus. Thus, the procapsid has the capacity to sequester neutralizing antibody and protect the virus, promoting or restoring a successful infectionin vitro. This important observation should be considered in the future design and development of vaccines and therapeutics.

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