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Transepithelial Electrical Resistance (transepithelial + electrical_resistance)
Selected AbstractsCampylobacter and IFN, interact to cause a rapid loss of epithelial barrier integrityINFLAMMATORY BOWEL DISEASES, Issue 3 2008Louisa E.N. Rees PhD Abstract Background: The intestinal epithelium is a single layer of polarized cells and is the primary barrier separating foreign antigen and underlying lymphoid tissue. IFN, alters epithelial barrier function during inflammation by disrupting tight cell junctions and facilitating the paracellular transport of luminal antigens. The aim of this work was to determine whether Campylobacter infection of cells exposed to IFN, would lead to greater disruption of cell monolayers and hence increased bacterial translocation. Methods: Monolayers were polarized on Transwell polycarbonate membranes for 14 days and then cultured in the presence or absence of 100 U/mL IFN,. Campylobacter was added to the apical side of the monolayer at an MOI of 30. Transepithelial electrical resistance (TEER) was recorded and bacteria in the basal well counted every 2 hours. Cells were stained for occludin, actin, and nuclear DNA, and cell viability determined by measurement of apoptosis. Results: In the presence of IFN,, TEER dropped significantly after 18 hours, indicating a reduction in barrier function. A further significant decrease was seen in the presence of both IFN, and Campylobacter, indicating a synergistic effect, and cellular morphology and viability were affected. Bacterial translocation across the monolayer was also significantly greater in the presence of IFN,. Conclusions: These combined effects indicate that Campylobacter infection concomitant with intestinal inflammation would result in a rapid and dramatic loss of epithelial barrier integrity, which may be a key event in the pathogenesis of Campylobacter -mediated colitis and the development of bloody diarrhea. (Inflamm Bowel Dis 2007) [source] Disruption effects of monophthalate exposures on inter-Sertoli tight junction in a two-compartment culture modelENVIRONMENTAL TOXICOLOGY, Issue 3 2008Yun-Hui Zhang Abstract Phthalates are suspect environmental endocrine disruptors that may affect male reproduction and development by disturbing androgen synthesis and cell,cell interactions in the seminiferous epithelium. The in vivo metabolites, monophthalates, are thought to be the active agents, and toxicant effects including testicular damage and decreased sperm motility have been described previously. In this study, the aim was to investigate the effect of monophthalates on Sertoli cells using a two-compartment cell culture model, asking whether tight junction protein structures are affected, compromising the blood-testis barrier and contributing to male-mediated toxicity. Sertoli cells were isolated from Sprague Dawley rat testes and seeded onto the filters of two-compartment wells. A Sertoli cell monolayer was allowed to form, whereupon the cultures were treated with 0, 10, 30, 150, and 600 ,mol/L monobutyl phthalate (MBP) or mono-2-ethylhexyl phthalate (MEHP) for 24 h. Effects on the tight junctions between adjacent Sertoli cells were studied by light and transmission electron microscopy, the transepithelial electrical resistance (TEER) assay, and immunofluorescence localization. Results showed that exposures to monophthalates destroyed tight junctional structure in Sertoli cell monolayers in a dose-depended manner, as evidenced by a loss of single-cell layer organization in the cultures, decline of TEER value, and decreased expression of proteins associated with tight junctions such as zonula occludens-1 (ZO-1), F-actin, and Occludin. The changes were observed at doses of 150 and 600 ,mol/L, which is 10,100 times higher relative to estimated human exposures from the environment. These results are consistent with monophthalate-induced damage to tight junctions between adjacent Sertoli cells, suggesting that damage to Sertoli cell tight junctions induced by monophthalates may be an underlying mechanism of their male-mediated reproductive toxicity. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Effect of natural commensal-origin DNA on toll-like receptor 9 (TLR9) signaling cascade, chemokine IL-8 expression, and barrier integritiy of polarized intestinal epithelial cellsINFLAMMATORY BOWEL DISEASES, Issue 3 2010Darab Ghadimi Abstract Background and Aim: The intestinal epithelium is constantly exposed to high levels of genetic material like bacterial DNA. Under normal physiological conditions, the intestinal epithelial monolayer as a formidable dynamic barrier with a high-polarity structure facilitates only a controlled and selective flux on components between the lumen and the underlining mucosa and even is able to facilitate structure-based macromolecules movement. The aim of this study was to test the effect of natural commensal-origin DNA on the TLR9 signaling cascade and the barrier integrity of polarized intestinal epithelial cells (IECs). Methods: Polarized HT-29 and T84 cells were treated with TNF-, in the presence or absence of DNA from Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum. TLR9 and interleukin-8 (IL-8) mRNA expression was assessed by semiquantitative and TaqMan real-time reverse-transcription polymerase chain reaction. Expression of TLR9 protein, degradation of inhibitor of kappa B alpha (I,B,), and p38 mitogen-activated protein kinase (p38 MAP) phosphorylation were assessed by Western blotting. To further reveal the role of TLR9 signaling, the TLR9 gene was silenced by siRNA. IL-8 secretion was measured by an enzyme-linked immunosorbent assay. Nuclear factor-kappa B (NF-,B) activity was assessed by the electrophoretic mobility shift assay (EMSA) and NF-,B-dependent luciferase reporter gene assays. As an indicator of tight junction formation and monolayer integrity of epithelial cell monolayers, transepithelial electrical resistance (TER) was repetitively monitored. Transmonolayer movement of natural commensal-origin DNA across monolayers was monitored using qRT-PCR and nested PCR based on bacterial 16S rRNA genes. Results: In response to apically applied natural commensal-origin DNA, polarized HT-29 and T84 cells enhanced expression of TLR9 in a specific manner, which was subsequently associated with attenuation of TNF-,-induced NF-,B activation and NF-,B-mediated IL-8 expression. TLR9 silencing abolished this inhibitory effect. Apically applied LGG DNA attenuated TNF-,-enhanced NF-,B activity by reducing I,B, degradation and p38 phosphorylation. LGG DNA did not decrease the TER but rather diminished the TNF-,-induced TER reduction. Translocation of natural commensal-origin DNA into basolateral compartments did not occur under tested conditions. Conclusions: Our study indicates that TLR9 signaling mediates, at least in part, the anti-inflammatory effects of natural commensal-origin DNA on the gut because TLR9 silencing abolished the inhibitory effect of natural commensal-origin DNA on TNF-,-induced IL-8 secretion in polarized IECs. The nature of the TLR9 agonist, the polarity of cells, and the tight junction integrity of IECs has to be taken into account in order to predict the outcome of TLR9 signaling. (Inflamm Bowel Dis 2010) [source] Changes in the expression of claudins and transepithelial electrical resistance of mouse Sertoli cells by Leydig cell cocultureINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2003M. C. Gye Summary In the testis, tight junctions (TJs) between adjacent Sertoli cells are important for the formation of blood,testis barrier (BTB). To verify the role of paracrine interactions between the Sertoli and Leydig cells in the structure and function of BTB in testis, the expression of claudin-1 and -11, and transepithelial electrical resistance (TER) of the mouse Sertoli cells were examined under the Leydig cell coculture. TER of Sertoli cell monolayer was significantly larger under the Leydig cell coculture in comparison with the control culture. Meanwhile, the expression of claudin-1 slightly decreased and claudin-11 significantly increased in the Sertoli cells in the Leydig cell coculture compared with control. Testosterone significantly increased claudin-11 expression in cultured Sertoli cells. Taken together, it suggested that Leydig cell coculture changed the structure and functions of inter-Sertoli TJs in vitro. Interactions between Leydig and Sertoli cells might be involved in the development of functional blood testis barrier in mouse testis. [source] Establishment and characterization of immortalized human gingival keratinocyte cell linesJOURNAL OF PERIODONTAL RESEARCH, Issue 6 2008S. Gröger Background and Objective:, Primary human keratinocytes are used to analyze the properties of the oral epithelium and the early stages of oral bacterial infections. In vitro, these cells are characterized by their short life span and restricted availability. Approaches for culturing these cells will end after approximately 6,10 passages as a result of entry into apoptosis. For this reason, it is important to generate cell lines suitable for obtaining an unlimited source of cells. Therefore, the aim of the present study was to generate gingival keratinocyte cell lines and to compare their in vitro behaviour with those of primary human gingival keratinocytes. Material and Methods:, Primary human gingival keratinocytes were immortalized with a combination of the human papilloma virus onkoproteins E6 and E7. The pattern of the cytokeratins, involucrin and filaggrin was investigated by intracellular staining using flow cytometry. This method allows quantitative analysis of the expression of a variety of intracellular or extracellular markers. Results:, The immortalized cell lines showed many morphological similarities, expressing a cytokeratin pattern that is comparable with that of primary gingival keratinocytes. Furthermore, they developed transepithelial electrical resistance, which is a marker for the generation of tight junctions. These results indicate that the cells might be able to act as an epithelial barrier, reflecting the reaction of primary human cells. Conclusion:, The establishment of a continuous line of human gingival epithelial cells with functional characteristics of the epithelial barrier provides a valuable in vitro model for using to study the early steps of gingival/periodontal infections. [source] Cytotoxicity evaluation of enzyme inhibitors and absorption enhancers in Caco-2 cells for oral delivery of salmon calcitoninJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2004Rakhi B. Shah Abstract The usefulness of enzyme inhibitors and absorption enhancers with least mucosal cell cytotoxicity was evaluated on Caco-2 cell monolayers. The temporal cytotoxicity of several protease inhibitors at 500 ,g/mL (e.g., turkey and chicken ovomucoids, aprotinin, and Protease Inhibitor Cocktail) and absorption enhancers [e.g., cholate (3%), glycocholate (3%), glycosursodeoxycholate (3%), ethylenediaminetetraacetic acid (EDTA, 0.1%), hydroxypropyl-,-cyclodextrin (HP-,-CD, 5%), hydroxypropyl-,-cylcodextrin (HP-,-CD, 5%), ,-cylcodextrin (,-CD, 5%), tetradecyl-,- D -maltoside (0.25%), octylglucoside (0.25%), citric acid (10%), glycyrrhetinic acid (0.34 mM), and Tween-80® (0.1%)] was measured by monitoring their effect on Caco-2 cell viability. Cell viability was measured by mannitol permeability measurements, transepithelial electrical resistance (TEER) measurements, DNA-propidium iodide staining assay, and WST-1 assay (tetrazolium salt based assay). Sodium dodecyl sulfate (0.1%), a potent surfactant, was used as a positive control. Chicken and turkey ovomucoids were nontoxic to cells as evaluated by all the methods used. Aprotinin decreased the TEER, whereas plasma membrane damage was seen with Protease Inhibitor Cocktail after a 24-h period. With respect to the absorption enhancers, the toxicity increased directly as a result of an increase in the time of incubation. The enhancers EDTA and HP-,-CD can be used safely for a short period of time, whereas glycosursodeoxycholate, glycyrrhetinic acid, octylglucoside, HP-,-CD, and ,-CD can be used for a longer period. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93: 1070,1082, 2004 [source] Mechanisms of cytoprotective effect of amino acids on local toxicity caused by sodium laurate, a drug absorption enhancer, in intestinal epitheliumJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2002Yoko Endo Abstract Several amino acids, including L -glutamine (L -Gln), were found to protect the intestinal epithelial cells from the local toxicity caused by a drug absorption enhancer, sodium laurate (C12), in our previous study. To develop more efficient and safer formulations for enhancing drug absorption, the mechanisms of cytoprotection by amino acids were studied using rats and Caco-2 cells. Four amino acids, including L -Gln, could generally maintain the absorption-promoting action of C12, although taurine tended to attenuate it. Three amino acids, except for L -Gln, significantly suppressed the decrease in the transepithelial electrical resistance caused by C12. Quercetin, an inhibitor for biosynthesis of heat shock protein 70 (HSP70), masked only the protective effect of L -Gln in both rat large intestine and Caco-2 cells. Western blot analysis indicated clearly that HSP70 is induced extensively only by the addition of L -Gln in both rat large-intestinal cells and Caco-2 cells. C12 was found to increase the intracellular concentration of Ca2+ ([Ca2+]i) remarkably, and amino acids, especially L -arginine, L -methionine, and taurine, significantly attenuated the increase in [Ca2+]i caused by C12. Furthermore, although C12 stimulated the release of histamine, an inflammatory mediator, from rat large-intestinal tissue, amino acids were also found to suppress the release of histamine enhanced by C12. The results in the present study showed that an induction of HSP70, a decrease in [Ca2+]i elevated by C12, and a suppression of histamine release stimulated by C12 should be involved in the mechanisms behind the cytoprotective action of amino acids against the local toxicity caused by C12. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:730,743, 2002 [source] Tumor necrosis factor-, and interferon-, directly impair epithelial barrier function in cultured mouse cholangiocytesLIVER INTERNATIONAL, Issue 1 2003Hanada Shinichiro Abstract:Background/Aims: In primary biliary cirrhosis (PBC), cytokines from CD4 + T lymphocytes were suggested to contribute to the intralobular bile duct damage together with cellular immunity by CD8 + T lymphocytes. Recently, we reported that immunolocalization of 7H6 , a tight junction (TJ)-associated protein , was significantly diminished in cholangiocytes in the PBC liver. In this study, we examined the direct effects of several cytokines , tumor necrosis factor-, (TNF-,), interferon-, (IFN-,), interleukin-2 and 4 (IL-2 and 4) , on TJ in immortalized mouse cholangiocytes. Moreover, we examined the inhibitory effect of ursodeoxycholic acid (UDCA)on cytokine-induced changes in paracellular permeability. Methods: Barrier function of TJ was evaluated by measuring transepithelial electrical resistance (TER) and 3H-inulin flux. We also performed immunostaining and immunoblotting for TJ-associated proteins , claudin-1 and -3, occludin, zonula occluden-1 (ZO-1) and 7H6. Results: TNF-, and IFN-,, but neither IL-2 nor IL-4, significantly decreased TER (P < 0.005). 3H-inulin flux studies confirmed IFN-,-induced increases in paracellular permeability of cholangiocytes (P < 0.001). In immunostaining and immunoblotting studies, TJ-associated proteins were well preserved in TNF-,- or IFN-,-treated cells. Ursodeoxycholic acidhas been found to have no inhibitory effect on increased paracellular permeability induced by TNF-, or IFN-,. Conclusion: These findings show that TNF-, and IFN-, disrupt barrier function of TJ in cholangiocytes without major structural changes to TJ and suggest that disruption of TJ function and subsequent leakage of the bile constituents may influence the aggravation of cholestasis in PBC. [source] A modified technique for the impregnation of lanthanum tracer to study the integrity of tight junctions on cells grown on a permeable substrateMICROSCOPY RESEARCH AND TECHNIQUE, Issue 10 2006Harriet Nilsson Abstract Ionic lanthanum is commonly used to trace permeability pathways across epithelia and endothelia in biological electron microscopy. A method for obtaining a uniformly dense precipitate of lanthanum is described. The method, which is a modification of the technique described by Shaklai and Tavassoli (1977) was suitable for fixation of cell cultures grown on permeable filter inserts and was successfully applied to study opening of tight junctions by hypertonic solutions in the airway epithelial cell line 16HBE14o,. The preparation method formed the basis for a semiquantitative morphological determination in which the tight junctions were subdivided as "intact," "weakened," and "open." By using this modified technique, it could be demonstrated that opening of tight junctions in airway epithelial cells increased, with increasing osmolarity with electrolytes having a stronger effect than nonelectrolytes. A significant linear relationship was found between the osmolarity of the medium and the open state of the tight junctions (as determined by the semiquantitative morphological technique) or the transepithelial electrical resistance. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source] Assessment of a bioactive compound for its potential antiinflammatory property by tight junction permeabilityPHYTOTHERAPY RESEARCH, Issue 12 2005Young Hoon Bai Abstract Lactobacillus probiotic strains are proving to be abundant sources of bioactive components, including antiinflammatory components. Lifree was made of fruits fermented by Lactobacillus paracasei, Lactobacillus reuterrii and Saccharomyces cerevisiae. This study was designed to test these compounds in cell assays measuring epithelial barrier function and proliferation in the first instance. Cell proliferation was measured in mouse fibroblasts cells (3T3NIH) and rat intestinal epithelial cells (IEC-6), and tight junction activity in the kidney epithelial cell line (MDCK). Tight junction permeability was assessed by measuring transepithelial electrical resistance (TER) across confluent monolayers, following the addition of Lifree with or without a challenge with EGTA. Lifree promoted tight junction formation and recovery following loss of TER from challenge with EGTA. On the other hand, Lifree did not stimulate cell growth in either 3T3NIH and IEC-6 cells. Lifree stimulates tight junction maintenance and formation, suggesting it may have potential antiinflammatory properties. Copyright © 2005 John Wiley & Sons, Ltd. [source] Rapid identification of differentiation markers from whole epithelial cells by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and statistical analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2008Laure F. Marvin-Guy Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was applied to identify markers for cellular differentiation. The differentiation of a human colon epithelial carcinoma T84 cell line was monitored over a period of 28 days by transepithelial electrical resistance (TER) measurements, alkaline phosphatase (AP) assay, and MALDI-TOF mass spectral fingerprints combined with statistical analysis. MALDI-MS generated specific mass spectral fingerprints characteristic of cell differentiation. Twenty-two ions were selected as diagnostic signals of fully differentiated T84 cells. Ten protein ion signals, detected by MALDI-MS and validated by statistical analysis, were proposed as T84 cell differentiation markers. Among these signals, ubiquitin was identified as a T84 cell differentiation marker by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Moreover, depending on the concentration of the cells seeded on the growth support, it was possible to predict the timing of the exponential phase and of cellular differentiation by MALDI-MS-derived marker ions. MALDI-TOFMS was compared to other methods for the determination of cellular differentiation: TER measurements are rapid but yield limited information as to the cellular differentiation state. AP assays are more specific for the differentiation state but take more time. By contrast, MALDI-MS has been found to be a fast, sensitive and precise method for cell differentiation assessment and provides the opportunity for multiplexing and high throughput. Moreover, the consumable costs per assay are very low. Copyright © 2008 John Wiley & Sons, Ltd. [source] Establishment of a matrix-associated transepithelial resistance invasion assay to precisely measure the invasive potential of synovial fibroblastsARTHRITIS & RHEUMATISM, Issue 9 2009Christina Wunrau Objective Synovial fibroblasts (SFs) contribute to several aspects of the pathogenesis of rheumatoid arthritis (RA) and have been implicated most prominently in the progressive destruction of articular cartilage. Targeting the invasive phenotype of RASFs has therefore gained increasing attention, but the precise measurement of their invasive capacity and the evaluation of potential treatment effects constitute a challenge that needs to be addressed. This study used a novel in vitro invasion assay based on the breakdown of transepithelial electrical resistance to determine the course of fibroblast invasion into extracellular matrix. Methods A matrix-associated transepithelial resistance invasion (MATRIN) assay was used to assess SFs from patients with RA in comparison with SFs from patients with osteoarthritis (OA). The SFs were grown on a commercially available collagen mix that was placed onto the upper side of a Transwell polycarbonate membrane. In addition, freshly isolated cartilage extracts were studied to assess the conditions in vivo. Under this membrane, a monolayer of MDCK-C7 cells was seeded to create a high electrical resistance. Results Invasion of fibroblasts into the matrix affected the integrity of the MDCK-C7 monolayer and led to a measurable decrease and subsequent breakdown of electrical resistance. Unlike in the assay with OASFs, which did not achieve a breakdown of resistance up to 72 hours, RASFs exhibited a pronounced invasiveness in this assay, with a 50% breakdown after 42 hours. Treatment of fibroblasts with either a matrix metalloproteinase inhibitor or antibodies against ,1 integrin significantly reduced the invasiveness of RASFs. Conclusion The MATRIN assay is a valuable and sensitive biologic assay system that can be used to determine precisely the invasive potential of RASFs in vitro, and thus would be suitable for screening anti-invasion compounds. [source] Development of the method for evaluating protective effect of food factors on THP-1-induced damage to human intestinal Caco-2 monolayersBIOFACTORS, Issue 1-4 2004Fumiko Watanabe Abstract Immune cells located in the intestinal epithelium interact with intestinal epithelial cells via soluble factors. In this study, a new in vitro model using a coculture system was constructed to analyze the interaction between intestinal epithelial cells and macrophage-like cells. Human intestinal epithelial Caco-2 cells were differentiated on semipermeable membranes. Human monocytic THP-1 cells were differentiated to macrophage-like cells and then cocultured on the basolateral side of the Caco-2 cell monolayers. By coculturing for 48 hours, an increased release of lactate dehydrogenase from the Caco-2 cells and a decrease in the transepithelial electrical resistance of the monolayers were observed, suggesting that the coculture with THP-1 induced some disruption of the Caco-2 cells. This disruption was significantly suppressed by adding the anti-TNF-, antibody to the medium, suggesting that TNF-, secreted from THP-1 caused damage to the Caco-2 cells. It is also suggested that this phenomenon is similar to that observed with inflammatory bowel disease (IBD). The effects of food factors on the cells in this coculture system were examined. The disruption of the Caco-2 cell monolayers was significantly reduced by adding caffeine to the medium on the apical side. It is hoped that this coculture system will be a good model for the treatment of IBD. [source] Effect of lectins on the transport of food ingredients in Caco-2 cell culturesBIOFACTORS, Issue 1-4 2004Y. Ohno Abstract We investigated the effect of several lectins, such as soy bean lectin (SBA), concanavalin A (Con A), and wheat germ agglutinin (WGA), on the transport of some food ingredients (isoflavones, quercetin glycosides, carnosine/anserine) across Caco-2 cell monolayers. After incubation of food ingredients (0.03,2 mmol/L) in the presence or absence of lectins (1,180 ,/ml) on the apical side, aliquots were taken from the apical and basolateral solution, and were subjected to HPLC analysis. We also examined the effect of lectins on the permeability of the tight junction by measuring the transepithelial electrical resistance (TER) value of the Caco-2 cell monolayer. Isoflavones, which was not transported to the basolateral solution without lectins, could be transported in the presence of lectins, whereas their aglycones were detected at the same levels with or without the lectin treatment. The transport of quercetin glycosides also increased in the presence of lectins, however, that of peptides was not affected by the lectins. Con A and WGA, but SBA, decreased the TER value, indicating that Con A and WGA increased the transport via paracellular pathway, whereas SBA did via a different pathway. [source] A microfluidic bioreactor with integrated transepithelial electrical resistance (TEER) measurement electrodes for evaluation of renal epithelial cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2010Nicholas Ferrell Abstract We have developed a bilayer microfluidic system with integrated transepithelial electrical resistance (TEER) measurement electrodes to evaluate kidney epithelial cells under physiologically relevant fluid flow conditions. The bioreactor consists of apical and basolateral fluidic chambers connected via a transparent microporous membrane. The top chamber contains microfluidic channels to perfuse the apical surface of the cells. The bottom chamber acts as a reservoir for transport across the cell layer and provides support for the membrane. TEER electrodes were integrated into the device to monitor cell growth and evaluate cell,cell tight junction integrity. Immunofluorescence staining was performed within the microchannels for ZO-1 tight junction protein and acetylated ,-tubulin (primary cilia) using human renal epithelial cells (HREC) and MDCK cells. HREC were stained for cytoskeletal F-actin and exhibited disassembly of cytosolic F-actin stress fibers when exposed to shear stress. TEER was monitored over time under normal culture conditions and after disruption of the tight junctions using low Ca2+ medium. The transport rate of a fluorescently labeled tracer molecule (FITC-inulin) was measured before and after Ca2+ switch and a decrease in TEER corresponded with a large increase in paracellular inulin transport. This bioreactor design provides an instrumented platform with physiologically meaningful flow conditions to study various epithelial cell transport processes. Biotechnol. Bioeng. 2010;107:707,716. © 2010 Wiley Periodicals, Inc. [source] RAPID EFFECT OF PROGESTERONE ON TRANSEPITHELIAL RESISTANCE OF HUMAN FETAL MEMBRANES: EVIDENCE FOR NON-GENOMIC ACTIONCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2008CH Verikouki SUMMARY 1The factors that regulate human fetal membrane transport mechanisms are unknown. The aim of the present study was to investigate the effect of progesterone on transepithelial electrical resistance (RTE) in the human amniochorion. 2Fetal membranes from uncomplicated term pregnancies were obtained immediately after vaginal or Caesarean deliveries. Intact pieces were mounted as planar sheets separating an Ussing chamber. Progesterone (10,4 to 10,7 mol/L), mifepristone (10,4 to 10,8 mol/L) and combinations of progesterone plus mifepristone were applied to the chambers facing the fetal or maternal sides of the membrane. The RTE was measured before and 1, 5, 10, 15, 20, 25, 30, 45 and 60 min after each solution was added (at 37°C). The RTE was calculated in ,.cm2, according to Ohm's law. 3The mean (±SEM) basal value of RTE before the application of any substance in all experiments was 29.1 ± 0.4 ,.cm2., The net change in the RTE (,RTE) in relation to the basal value was calculated in each experiment. Progesterone, mifepristone and the combination of progesterone and mifepristone induced a rapid, surge-type increase in RTE during the 1st min on both sides of the membrane. The combination of progesterone plus mifepristone exerted a synergistic action. The effect was stronger on the fetal side than on the maternal side for all substances tested (P < 0.05). The highest ,RTE during the 1st min on the fetal side was seen with the combination of progesterone plus mifepristone (4.0 ± 0.3 ,.cm2) and the lowest ,RTE occurred with mifepristone (1.5 ± 0.1 ,.cm2). 4The present results demonstrated that the RTE of human fetal membranes increases rapidly in response to progesterone. It is possible that changes in RTE play a role in the control of membrane permeability during pregnancy. [source] | ||||||||||||||||