1
|
Stolwijk JA, Matrougui K, Renken CW, Trebak M. Impedance analysis of GPCR-mediated changes in endothelial barrier function: overview and fundamental considerations for stable and reproducible measurements. Pflugers Arch 2015; 467:2193-218. [PMID: 25537398 PMCID: PMC4480219 DOI: 10.1007/s00424-014-1674-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 12/19/2022]
Abstract
The past 20 years has seen significant growth in using impedance-based assays to understand the molecular underpinning of endothelial and epithelial barrier function in response to physiological agonists and pharmacological and toxicological compounds. Most studies on barrier function use G protein-coupled receptor (GPCR) agonists which couple to fast and transient changes in barrier properties. The power of impedance-based techniques such as electric cell-substrate impedance sensing (ECIS) resides in its ability to detect minute changes in cell layer integrity label-free and in real-time ranging from seconds to days. We provide a comprehensive overview of the biophysical principles, applications, and recent developments in impedance-based methodologies. Despite extensive application of impedance analysis in endothelial barrier research, little attention has been paid to data analysis and critical experimental variables, which are both essential for signal stability and reproducibility. We describe the rationale behind common ECIS data presentation and interpretation and illustrate practical guidelines to improve signal intensity by adapting technical parameters such as electrode layout, monitoring frequency, or parameter (resistance versus impedance magnitude). Moreover, we discuss the impact of experimental parameters, including cell source, liquid handling, and agonist preparation on signal intensity and kinetics. Our discussions are supported by experimental data obtained from human microvascular endothelial cells challenged with three GPCR agonists, thrombin, histamine, and sphingosine-1-phosphate.
Collapse
Affiliation(s)
- Judith A Stolwijk
- The SUNY College of Nanoscale Science and Engineering (CNSE), SUNY Polytechnic Institute, State University of New York, 257 Fuller Rd., Albany, NY, 12203, USA
- Applied BioPhysics Inc., Troy, NY, USA
| | - Khalid Matrougui
- Department of Physiological Sciences, East Virginia Medical School, Norfolk, VA, USA
| | | | - Mohamed Trebak
- The SUNY College of Nanoscale Science and Engineering (CNSE), SUNY Polytechnic Institute, State University of New York, 257 Fuller Rd., Albany, NY, 12203, USA.
| |
Collapse
|
2
|
Experimental tools to monitor the dynamics of endothelial barrier function: a survey of in vitro approaches. Cell Tissue Res 2014; 355:485-514. [DOI: 10.1007/s00441-014-1810-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/13/2014] [Indexed: 02/05/2023]
|
3
|
Vincent PE, Weinberg PD. Flow-dependent concentration polarization and the endothelial glycocalyx layer: multi-scale aspects of arterial mass transport and their implications for atherosclerosis. Biomech Model Mechanobiol 2013; 13:313-26. [DOI: 10.1007/s10237-013-0512-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 06/26/2013] [Indexed: 10/26/2022]
|
4
|
Young EWK, Watson MWL, Srigunapalan S, Wheeler AR, Simmons CA. Technique for real-time measurements of endothelial permeability in a microfluidic membrane chip using laser-induced fluorescence detection. Anal Chem 2010; 82:808-16. [PMID: 20050596 DOI: 10.1021/ac901560w] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Characterizing permeability of the endothelium that lines blood vessels and heart valves provides fundamental physiological information and is required to evaluate uptake of drugs and other biomolecules. However, current techniques used to measure permeability, such as Transwell insert assays, do not account for the recognized effects of fluid flow-induced shear stress on endothelial permeability or are inherently low-throughput. Here we report a novel on-chip technique in a two-layer membrane-based microfluidic platform to measure real-time permeability of endothelial cell monolayers on porous membranes. Bovine serum albumin (a model protein) conjugated with fluorescein isothiocyanate was delivered to an upper microchannel by pressure-driven flow and was forced to permeate a poly(ethylene terephthalate) membrane into a lower microchannel, where it was detected by laser-induced fluorescence. The concentration of the permeate at the point of detection varied with channel flow rates in agreement to less than 1% with theoretical analyses using a pore flow model. On the basis of the model, a sequential flow rate stepping scheme was developed and applied to obtain the permeability of cell-free and cell-bound membrane layers. This technique is a highly sensitive, novel microfluidic approach for measuring endothelial permeability in vitro, and the use of micrometer-sized channels offers the potential for parallelization and increased throughput compared to conventional shear-based permeability measurement methods.
Collapse
Affiliation(s)
- Edmond W K Young
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada, M5S 3G8
| | | | | | | | | |
Collapse
|
5
|
Abstract
Vascular endothelial growth factors (VEGFs) are key regulators of permeability. The principal evidence behind how they increase vascular permeability in vivo and in vitro and the consequences of that increase are addressed here. Detailed analysis of the published literature has shown that in vivo and in vitro VEGF-mediated permeability differs in its time course, but has common involvement of many specific signalling pathways, in particular VEGF receptor-2 activation, calcium influx through transient receptor potential channels, activation of phospholipase C gamma and downstream activation of nitric oxide synthase. Pathways downstream of endothelial nitric oxide synthase appear to involve the guanylyl cyclase-mediated activation of the Rho–Rac pathway and subsequent involvement of junctional signalling proteins such as vascular endothelial cadherin and the tight junctional proteins zona occludens and occludin linked to the actin cytoskeleton. The signalling appears to be co-ordinated through spatial organization of the cascade into a signalplex, and arguments for why this may be important are considered. Many proteins have been identified to be involved in the regulation of vascular permeability by VEGF, but still the mechanisms through which these are thought to interact to control permeability are dependent on the experimental system, and a synthesis of existing data reveals that in intact vessels the co-ordination of the pathways is still not understood.
Collapse
Affiliation(s)
- David O Bates
- Microvascular Research Laboratories, Department of Physiology and Pharmacology, School of Veterinary Sciences, Bristol Heart Institute, University of Bristol, Southwell Street, Bristol, UK.
| |
Collapse
|
6
|
Russell S, Cancel LM, Tarbell JM, Rumschitzki DS. A protein diffusion model of the sealing effect. Chem Eng Sci 2009; 64:4504-4514. [PMID: 36588620 PMCID: PMC9802672 DOI: 10.1016/j.ces.2009.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Water transport across the arterial endothelium is believed primarily to occur through breaks in the tight junction strands at the cell periphery between neighboring cells. Additional proteins arriving at the tight junction can close these breaks, thereby attenuating this water flux. Motivated by evidence that the diffusion of presynthesized protein from the interior of the cell to and incorporation into the cell border is the mechanism of endothelial tight junctional sealing, we develop a diffusion-limited mathematical model of intercellular gap sealing. A single endothelial cell is represented as a thin, axisymmetric disk, initially containing a uniform distribution of junctional protein that does not interact with the apical or basal cell surfaces. Upon application of a transmural pressure gradient, water flows through the junctional cleft, and tight junction remodeling begins. We assume that proteins at the junction are instantaneously incorporated into its strand, dropping the free protein concentration at the cell periphery to zero. This sets the diffusion of intracellular proteins toward the junction in motion. The solution of this one-dimensional initial value problem provides excellent fits to current and previously published experimental data over a wide variety of conditions. It yields three physically meaningful parameters for each fit, including a protein diffusivity in the cytoplasm that varies little within experimental treatments. Statistical variation of these parameters allows rational comparison of experimental runs and identification of outlier runs.
Collapse
Affiliation(s)
- Stewart Russell
- Department of Biomedical Engineering, The City College of New York, The Graduate School, University Center of CUNY, New York, NY 10031, USA
| | - Limary M. Cancel
- Department of Biomedical Engineering, The City College of New York, The Graduate School, University Center of CUNY, New York, NY 10031, USA
| | - John M. Tarbell
- Department of Biomedical Engineering, The City College of New York, The Graduate School, University Center of CUNY, New York, NY 10031, USA
| | - David S. Rumschitzki
- Department of Biomedical Engineering, The City College of New York, The Graduate School, University Center of CUNY, New York, NY 10031, USA
,Corresponding author. (D.S. Rumschitzki)
| |
Collapse
|
7
|
Palombo F, Danoux CB, Weinberg PD, Kazarian SG. Measurement of drug and macromolecule diffusion across atherosclerotic rabbit aorta ex vivo by attenuated total reflection-Fourier transform infrared imaging. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:044008. [PMID: 19725720 DOI: 10.1117/1.3174395] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Diffusion of two model drugs-benzyl nicotinate and ibuprofen-and the plasma macromolecule albumin across atherosclerotic rabbit aorta was studied ex vivo by attenuated total reflection-Fourier transform infrared (ATR-FTIR) imaging. Solutions of these molecules were applied to the endothelial surface of histological sections of the aortic wall that were sandwiched between two impermeable surfaces. An array of spectra, each corresponding to a specific location in the section, was obtained at various times during solute diffusion into the wall and revealed the distribution of the solutes within the tissue. Benzyl nicotinate in Ringer's solution showed higher affinity for atherosclerotic plaque than for apparently healthy tissue. Transmural concentration profiles for albumin demonstrated its permeation across the section and were consistent with a relatively low distribution volume for the macromolecule in the middle of the wall. The ability of albumin to act as a drug carrier for ibuprofen, otherwise undetected within the tissue, was demonstrated by multivariate subtraction image analysis. In conclusion, ATR-FTIR imaging can be used to study transport processes in tissue samples with high spatial and temporal resolution and without the need to label the solutes under study.
Collapse
Affiliation(s)
- Francesca Palombo
- Imperial College London, Department of Chemical Engineering and Chemical Technology, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | | | | | | |
Collapse
|
8
|
Phillips BE, Cancel L, Tarbell JM, Antonetti DA. Occludin independently regulates permeability under hydrostatic pressure and cell division in retinal pigment epithelial cells. Invest Ophthalmol Vis Sci 2008; 49:2568-76. [PMID: 18263810 DOI: 10.1167/iovs.07-1204] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The aim of this study was to determine the function of the tight junction protein occludin in the control of permeability, under diffusive and hydrostatic pressures, and its contribution to the control of cell division in retinal pigment epithelium. METHODS Occludin expression was inhibited in the human retinal pigment epithelial cell line ARPE-19 by siRNA. Depletion of occludin was confirmed by Western blot, confocal microscopy, and RT-PCR. Paracellular permeability of cell monolayers to fluorescently labeled 70 kDa dextran, 10 kDa dextran, and 467 Da tetramethylrhodamine (TAMRA) was examined under diffusive conditions or after the application of 10 cm H2O transmural pressure. Cell division rates were determined by tritiated thymidine incorporation and Ki67 immunoreactivity. Cell cycle inhibitors were used to determine whether changes in cell division affected permeability. RESULTS Occludin depletion increased diffusive paracellular permeability to 467 Da TAMRA by 15%, and permeability under hydrostatic pressure was increased 50% compared with control. Conversely, depletion of occludin protein with siRNA did not alter diffusive permeability to 70 kDa and 10 kDa RITC-dextran, and permeability to 70 kDa dextran was twofold lower in occludin-depleted cells under hydrostatic pressure conditions. Occludin depletion also increased thymidine incorporation by 90% and Ki67-positive cells by 50%. Finally, cell cycle inhibitors did not alter the effect of occludin siRNA on paracellular permeability. CONCLUSIONS The data suggest that occludin regulates tight junction permeability in response to changes in hydrostatic pressure. Furthermore, these data suggest that occludin also contributes to the control of cell division, demonstrating a novel function for this tight junction protein.
Collapse
Affiliation(s)
- Brett E Phillips
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033-0850, USA
| | | | | | | |
Collapse
|
9
|
DeMaio L, Antonetti DA, Scaduto RC, Gardner TW, Tarbell JM. VEGF increases paracellular transport without altering the solvent-drag reflection coefficient. Microvasc Res 2005; 68:295-302. [PMID: 15501249 DOI: 10.1016/j.mvr.2004.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Indexed: 10/26/2022]
Abstract
Vascular endothelial growth factor (VEGF) increases microvascular permeability and has been implicated in the development of numerous pathologies including diabetic retinopathy (DR), hypoxia/ischemia, and tumor biology. The transport pathways by which water and solutes cross the endothelium in response to VEGF, however, are not completely understood. We measured, in real time, bovine retinal endothelial cell (BREC) hydraulic conductivity (Lp), 70 kDa dextran permeability (Pe), and the solvent-drag reflection coefficient (sigma) before and after addition of 50 ng/ml VEGF. The diffusional permeability coefficient for dextran (Pd) was measured before pressure gradient application. The sudden application of a 10-cm H2O hydrostatic pressure gradient induced water and solute fluxes that decayed to steady-state values after approximately 2 h. Subsequently, the addition of VEGF significantly increased Lp and Pe by 4.3-fold +/- 0.7-fold and 3.0-fold +/- 0.3-fold, respectively, after 110 min; however, the reflection coefficient remained approximately constant throughout the experiment (approximately 0.8). These observations suggest that water and dextran utilize common paracellular channels across BREC monolayers. Furthermore, the addition of VEGF increases the number or availability of channels but does not alter the selectivity of the monolayer to 70 kDa dextran.
Collapse
Affiliation(s)
- Lucas DeMaio
- Department of Biomedical Engineering, The City College of The City University of New York, New York, NY 10031, USA
| | | | | | | | | |
Collapse
|
10
|
DeMaio L, Tarbell JM, Scaduto RC, Gardner TW, Antonetti DA. A transmural pressure gradient induces mechanical and biological adaptive responses in endothelial cells. Am J Physiol Heart Circ Physiol 2004; 286:H731-41. [PMID: 14527936 DOI: 10.1152/ajpheart.00427.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sudden increase in the transmural pressure gradient across endothelial monolayers reduces hydraulic conductivity ( Lp), a phenomenon known as the sealing effect. To further characterize this endothelial adaptive response, we measured bovine aortic endothelial cell (BAEC) permeability to albumin and 70-kDa dextran, Lp, and the solvent-drag reflection coefficients (σ) during the sealing process. The diffusional permeability coefficients for albumin (1.33 ± 0.18 × 10–6cm/s) and dextran (0.60 ± 0.16 × 10–6cm/s) were measured before pressure application. The effective permeabilities (measured when solvent drag contributes to solute transport) of albumin and dextran ( Pealband Pedex) were measured after the application of a 10 cmH2O pressure gradient; during the first 2 h of pressure application, Pealb, Pedex, and Lpwere significantly reduced by 2.0 ± 0.3-, 2.1 ± 0.3-, and 3.7 ± 0.3-fold, respectively. Immunostaining of the tight junction (TJ) protein zonula occludens-1 (ZO-1) was significantly increased at cell-cell contacts after the application of transmural pressure. Cytochalasin D treatment significantly elevated transport but did not inhibit the adaptive response, whereas colchicine treatment had no effect on diffusive permeability but inhibited the adaptive response. Neither cytoskeletal inhibitor altered σ despite significantly elevating both Lpand effective permeability. Our data suggest that BAECs actively adapt to elevated transmural pressure by mobilizing ZO-1 to intercellular junctions via microtubules. A mechanical (passive) component of the sealing effect appears to reduce the size of a small pore system that allows the transport of water but not dextran or albumin. Furthermore, the structures of the TJ determine transport rates but do not define the selectivity of the monolayer to solutes (σ).
Collapse
Affiliation(s)
- Lucas DeMaio
- Department of Chemical Engineering, Biomolecular Transport Dynamics Laboratory, The Pennsylvania State University, University Park 16802, USA
| | | | | | | | | |
Collapse
|
11
|
Suttorp N, Ehreiser P, Hippenstiel S, Fuhrmann M, Krüll M, Tenor H, Schudt C. Hyperpermeability of pulmonary endothelial monolayer: protective role of phosphodiesterase isoenzymes 3 and 4. Lung 2004; 174:181-94. [PMID: 8830194 DOI: 10.1007/bf00173310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The regulation of endothelial permeability is poorly understood. An increase in endothelial permeability in the pulmonary microvasculature, however, is critical in noncardiogenic pulmonary edema and other diffuse inflammatory reactions. In the present study thrombin and Escherichia coli hemolysin (HlyA), a membrane-perturbing bacterial exotoxin, were used to alter hydraulic permeability of porcine pulmonary artery and human endothelial cell monolayers. We also investigated the pharmacological approach of adenylyl cyclase activation/phosphodiesterase (PDE) inhibition to block endothelial hyperpermeability. Thrombin (1-5 units/ml) and HlyA (0.5-3 hemolytic units/ml) dose and time dependently (> 15 min) increased endothelial permeability. Forskolin, cholera toxin, and prostaglandin E1, which all stimulate adenylyl cyclase activity, abrogated this effect. One mM dibutyryl cAMP, a cell membrane-permeable cAMP analogue, was similarly active. Endothelial hyperpermeability was also reduced dose dependently by inhibitors of different PDE isoenzymes (motapizone, rolipram, and zardaverine, which block PDE3 and/or PDE4). The effectiveness of PDE inhibitors was increased in the presence of adenylyl cyclase activators. Analysis of cyclic nucleotide hydrolyzing PDE activity in lysates of human umbilical vein endothelial cells showed high activities of PDE isoenzymes 2, 3, and 4. Consistent with the functional data PDE3 and PDE4 were the major cAMP hydrolysis enzymes in intact endothelial cells. We conclude that the hyperpermeability of pulmonary endothelial monolayers, evoked by thrombin or HlyA, can be blocked by the simultaneous activation of adenylyl cyclase and inhibition of PDEs, especially of PDE3 and PDE4. The demonstration of PDE isoenzymes 2-4 in human endothelial cells will help optimize this therapeutic approach.
Collapse
Affiliation(s)
- N Suttorp
- Department of Internal Medicine, Justus Liebig-University of Giessen, Germany
| | | | | | | | | | | | | |
Collapse
|
12
|
Dye JF, Leach L, Clark P, Firth JA. Cyclic AMP and acidic fibroblast growth factor have opposing effects on tight and adherens junctions in microvascular endothelial cells in vitro. Microvasc Res 2001; 62:94-113. [PMID: 11516239 DOI: 10.1006/mvre.2001.2333] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endothelial adherens junctions (AJ) and tight junctions (TJ) are important determinants of vascular permeability and cell morphology. Here, we investigate their regulation, in primary human placental microvascular endothelial cell (HPMEC) cultures, by either aFGF plus heparin (ECGS) or elevated cAMP. The proliferation of HPMEC was weakly stimulated by ECGS, while cAMP was inhibitory. ECGS had little effect on transendothelial resistance (TER), but increased macromolecular permeability, whereas cAMP induced a twofold increase in TER and reduced macromolecular permeability. Ultrastructurally, ECGS-treated HPMEC exhibited an "activated" phenotype typified by proliferating cells, with poorly organized cell-cell junctions, whereas cAMP-treated cells appeared quiescent and markedly flattened with extended paracellular junctions, resembling endothelium in situ. The expression and localization of junctional molecules, F-actin, and junctional phosphotyrosine were examined by confocal microscopy and immunoblotting. Junctional molecules in ECGS-treated cells were less organized at lateral membranes than in control cells, whereas in cAMP-treated cells, they were highly localized at continuous contacts. These differences correlated with the intensity of junctional phosphotyrosine, being lowest with cAMP treatment. In the AJ of ECGS-treated and control cells, beta-catenin predominated but in cAMP-treated cells, gamma-catenin/plakoglobin was enriched. In addition, cAMP upregulated junctional expression of VE-cadherin and PECAM-1 and increased the levels of the TJ molecules occludin and ZO-1. The expression levels of junctional components, and their tyrosine phosphorylation, play an important role in dynamic regulation of endothelial cell-cell junctions.
Collapse
Affiliation(s)
- J F Dye
- Division of Biomedical Sciences, Imperial College School of Medicine, South Kensington, SW7 2AZ, UK
| | | | | | | |
Collapse
|
13
|
Tarbell JM, Demaio L, Zaw MM. Effect of pressure on hydraulic conductivity of endothelial monolayers: role of endothelial cleft shear stress. J Appl Physiol (1985) 1999; 87:261-8. [PMID: 10409584 DOI: 10.1152/jappl.1999.87.1.261] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Significant changes in transvascular pressure occur in pulmonary hypertension, microgravity, and many other physiological and pathophysiological circumstances. Using bovine aortic endothelial cells grown on porous, rigid supports, we demonstrate that step changes in transmural pressure of 10, 20, and 30 cmH(2)O induce significant elevations in endothelial hydraulic conductivity (L(p)) that require 5 h to reach new steady-state levels. The increases in L(p) can be reversed by addition of a stable cAMP analog (dibutyryl cAMP), and the increases in L(p) in response to pressure can be inhibited significantly with nitric oxide synthase inhibitors (N(G)-monomethyl-L-arginine and nitro-L-arginine methyl ester). The increase in L(p) was not due to pressure-induced stretch because the endothelial cell (EC) support was rigid. It is unlikely that the increase in L(p) was due to a direct effect of pressure because exposure of the cells to elevated pressure (25 cmH(2)O) for 4 h had no effect on the volume flux driven by a transmural pressure of 10 cmH(2)O. We hypothesize that elevated endothelial cleft shear stress induced by elevated transmural flow in response to elevated pressure stimulates the increase in L(p) through a nitric oxide-cAMP-dependent mechanism. This is consistent with recent studies of the effects of shear stress on the luminal surface of ECs. We provide simple estimates of endothelial cleft shear stress, which suggest magnitudes comparable to those imposed by blood flow on the luminal surface of ECs.
Collapse
Affiliation(s)
- J M Tarbell
- Biomolecular Transport Dynamics Laboratory, Department of Chemical Engineering and the Bioengineering Program, The Pennsylvania State University, University Park, Pennsylvania 16802-4400, USA.
| | | | | |
Collapse
|
14
|
Tschugguel W, Zhegu Z, Gajdzik L, Maier M, Binder BR, Graf J. High precision measurement of electrical resistance across endothelial cell monolayers. Pflugers Arch 1995; 430:145-7. [PMID: 7667075 DOI: 10.1007/bf00373850] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Effects of vasoactive agonists on endothelial permeability was assessed by measurement of transendothelial electrical resistance (TEER) of human umbilical vein endothelial cells (HUVECs) grown on porous polycarbonate supports. Because of the low values of TEER obtained in this preparation (< 5 omega cm2) a design of an Ussing type recording chamber was chosen that provided for a homogeneous electric field across the monolayer and for proper correction of series resistances. Precision current pulses and appropriate rates of sampling and averaging of the voltage signal allowed for measurement of < 0.1 omega resistance changes of the endothelium on top of a 21 omega series resistance of the support and bathing fluid layers. Histamine (10 microM) and thrombin (10 U/ml) induced an abrupt and substantial decrease of TEER, bradykinin (1 microM) was less effective, PAF (380 nM) and LTC4 (1 microM) had no effect. TEER was also reduced by the calcium ionophore A-23187 (10 microM). The technique allows for measurements of TEER in low resistance monolayer cultures with high precision and time resolution. The results obtained extend previous observations in providing quantitative data on the increase of permeability of HUVECs in response to vasoactive agonists.
Collapse
Affiliation(s)
- W Tschugguel
- Department of General and Experimental Pathology, University of Vienna School of Medicine, Austria
| | | | | | | | | | | |
Collapse
|
15
|
Turner MR. Effects of proteins on the permeability of monolayers of cultured bovine arterial endothelium. J Physiol 1992; 449:21-35. [PMID: 1522510 PMCID: PMC1176065 DOI: 10.1113/jphysiol.1992.sp019072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
1. Monolayers of arterial endothelium on porous membranes were exposed to a pressure of 15 cmH2O at 37 degrees C, or of 30 cmH2O at 0 degree C. At constant pressure, the rate of liquid flow per unit area (Jv/A) through each monolayer decreased with time, in the way previously described for cultured endothelium. This phenomenon has been called sealing. After Jv/A stabilized, the pressure was reduced and the hydraulic permeability (Lp) of the endothelium was calculated from the relationship between Jv/A and pressure. Endothelium was seen to be damaged after some experiments at 37 degrees C, but appeared undamaged after experiments at 0 degree C. 2. Bovine serum albumin (BSA) did not influence the Lp of cultured endothelium. At 37 degrees C, the mean (+/- S.E.M.) endothelial Lp was 47.2 +/- 7.3 x 10(-7) cm s-1 cmH2O-1 (n = 10) in the presence of BSA (5 g (100 ml)-1). This is not significantly different from the mean (+/- S.E.M.) Lp of 53.4 +/- 9.0 x 10(-7) cm s-1 cmH2O-1 (n = 9) in the absence of added protein (P greater than 0.10). At 0 degree C also, there was no significant difference between mean Lps in the presence of BSA (0.1 g (100 ml)-1) and in the absence of added protein. 3. Solutions of BSA (5 g (100 ml)-1 or of the neutral polymer Ficoll 70 (4 g (100 ml)-1) did not exert any effective osmotic pressure across endothelium at 37 or 0 degrees C, respectively. 4. BSA (0.1 g (100 ml)-1) did not enable solutions of Ficoll 70 (4 g (100 ml)-1) to exert an effective osmotic pressure across endothelium at 0 degree C. 5. The mean Lp of endothelium at 0 degree C was significantly lower in the presence of cationized ferritin (CF; 0.1 g (100 ml)-1) than in the absence of added protein (P less than 0.001). Native ferritin (NF; 0.1 g (100 ml)-1) had no effect on Lp. 6. In the presence of CF (0.1 g (100 ml)-1), solutions of Ficoll 70 (4 g (100 ml)-1) exerted a mean effective osmotic pressure of 27.7 cmH2O (n = 5) across endothelium at 0 degree C. The mean effective osmotic pressure exerted across endothelium by solutions of Ficoll 70 (4 g (100 ml)-1) plus NF (0.1 g (100 ml)-1) was 1.2 cmH2O (n = 4).
Collapse
Affiliation(s)
- M R Turner
- Department of Physiology and Biophysics, St Mary's Hospital Medical School, London
| |
Collapse
|