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Leonard, Maurice; Creed, Elizabeth; Brayden, David J.; Baird, Alan W.

doi:10.1023/a:1026454427621

Cited by 39 publications

(9 citation statements)

References 14 publications

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“…Importantly, the Papp of dexamethasone bromoacetate across E12 exposed to NAC (2.0×10 −5 cm/s) was also similar to that of dexamethasone reported in Caco-2, (0.9×10 −5 cm/s) [47], values indicative of passive transcellular transport. As dexamethasone is a moderately hydrophobic molecule with a log D of 1.95, the mucus gel should present a flux barrier to it, and this has already been demonstrated in E12 for barbiturates and testosterone [22].…”

Section: Discussionsupporting

confidence: 74%

Dexamethasone–pDMAEMA polymeric conjugates reduce inflammatory biomarkers in human intestinal epithelial monolayers

Keely

Ryan

Haddleton

et al. 2009

Journal of Controlled Release

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The mucoadhesive polymer, poly(dimethylamino)ethyl methacrylate (pDMAEMA) was synthesised by living radical polymerisation and subsequently conjugated by esterification to the anti-inflammatory corticosteroid, dexamethasone, to separately yield two concentrations of conjugates with ratios of 10:1 and 20:1 active:polymer. The hypothesis was to test whether the active agent maintained in vitro bioactivity when exposed to the apical side of human intestinal epithelial monolayers, Caco-2 and mucous-covered HT29-MTX-E12 (E12). HPLC analysis showed that 80% of the dexamethasone in both conjugates was attached to pDMAEMA. Similar to pDMAEMA, fluorescently-labelled dexamethasone-pDMAEMA conjugates were bioadhesive to Caco-2 and mucoadhesive to E12. Apical addition of conjugates suppressed mRNA expression of the inflammatory markers, NURR1 and ICAM-1 in E12 following stimulation by PGE2 and TNF-α, respectively. Conjugates also suppressed TNF-α stimulated cytokine secretion to the basolateral side of Caco-2 monolayers. pDMAEMA was inactive in these assays. Measurement of dexamethasone permeability from conjugates across monolayers suggested that conjugation reduced permeability compared to free dexamethasone. LDH assay indicated that conjugates were not cytotoxic to monolayers at high concentrations. Anti-inflammatory agents can therefore be successfully conjugated to polymers and they retain adhesion and bioactivity to enable formulation for topical administration.

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Section: Discussionsupporting

confidence: 74%

Dexamethasone–pDMAEMA polymeric conjugates reduce inflammatory biomarkers in human intestinal epithelial monolayers

Keely

Ryan

Haddleton

et al. 2009

Journal of Controlled Release

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“…TEER was monitored as an indication of tight junction formation and epithelial monolayer integrity as previously described [ 23 ]. Falcon®-Transwell inserts (0.4 μm pore size; BD Bioscience, Buccinasco, Italy) were coated with 0.01% type I rat-tail collagen (Sigma) and left to dry overnight under ultraviolet (UV) lights in 6-well plates.…”

Section: Methodsmentioning

confidence: 99%

Anti‐proliferative effect of rhein, an anthraquinone isolated from Cassia species, on Caco‐2 human adenocarcinoma cells

Aviello

Rowland

Gill

et al. 2010

J Cellular Molecular Medi

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In recent years, the use of anthraquinone laxatives, in particular senna, has been associated with damage to the intestinal epithelial layer and an increased risk of developing colorectal cancer. In this study, we evaluated the cytotoxicity of rhein, the active metabolite of senna, on human colon adenocarcinoma cells (Caco-2) and its effect on cell proliferation. Cytotoxicity studies were performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR) and trans-epithelial electrical resistance (TEER) assays whereas 3H-thymidine incorporation and Western blot analysis were used to evaluate the effect of rhein on cell proliferation. Moreover, for genoprotection studies Comet assay and oxidative biomarkers measurement (malondialdehyde and reactive oxygen species) were used. Rhein (0.1–10 μg/ml) had no significant cytotoxic effect on proliferating and differentiated Caco-2 cells. Rhein (0.1 and 1 μg/ml) significantly reduced cell proliferation as well as mitogen-activated protein (MAP) kinase activation; by contrast, at high concentration (10 μg/ml) rhein significantly increased cell proliferation and extracellular-signal-related kinase (ERK) phosphorylation. Moreover, rhein (0.1–10 μg/ml): (i) did not adversely affect the integrity of tight junctions and hence epithelial barrier function; (ii) did not induce DNA damage, rather it was able to reduce H2O2-induced DNA damage and (iii) significantly inhibited the increase in malondialdehyde and reactive oxygen species (ROS) levels induced by H2O2/Fe2+. Rhein was devoid of cytotoxic and genotoxic effects in colon adenocarcinoma cells. Moreover, at concentrations present in the colon after a human therapeutic dosage of senna, rhein inhibited cell proliferation via a mechanism that seems to involve directly the MAP kinase pathway. Finally, rhein prevents the DNA damage probably via an anti-oxidant mechanism.

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“…Comparative studies of solute permeability between in vivo and in vitro epithelium are limited, but available data for the two most commonly used bronchial epithelial cell lines, Calu-3 and 16HBE14o-, correlate well with primary epithelial cell cultures [97]. Permeability studies with in vitro epithelial cultures are more common and several studies have shown a very clear correlation between TEER values and diffusion rates of mannitol [91,98,99,100,101] as well as dextran [92,102,103,104]. Further studies by Man et al [91] illustrated this relationship by the disruption of E-cadherin function, resulting in the loss of TEER and increased permeability to mannitol and dextran paracellular flux.…”

Section: Analysis Of Epithelial Cell Polarizationmentioning

confidence: 99%

“…These primary human bronchial epithelial cells can be cultured in ALI conditions using a defined medium to drive a differentiation into ciliated and goblet cells with a high degree of polarization [185,193]. As most airway in vitro models build upon the work done with the intestinal epithelial cell line Caco-2 [95,104], which was cultured fully suspended in medium, initial work with airway epithelial cell lines were tested in similar conditions. Such liquid-covered conditions also offer some advantages, as particle uptake and transfer studies are more straightforward and TEER being easily monitored.…”

Section: Culture Conditionsmentioning

confidence: 99%

Polarized Airway Epithelial Models for Immunological Co-Culture Studies

Papazian

Würtzen

Hansen

2016

Int Arch Allergy Immunol

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Epithelial cells line all cavities and surfaces throughout the body and play a substantial role in maintaining tissue homeostasis. Asthma and other atopic diseases are increasing worldwide and allergic disorders are hypothesized to be a consequence of a combination of dysregulation of the epithelial response towards environmental antigens and genetic susceptibility, resulting in inflammation and T cell-derived immune responses. In vivo animal models have long been used to study immune homeostasis of the airways but are limited by species restriction and lack of exposure to a natural environment of both potential allergens and microflora. Limitations of these models prompt a need to develop new human cell-based in vitro models. A variety of co-culture systems for modelling the respiratory epithelium exist and are available to the scientific community. The models have become increasingly sophisticated and specific care needs to be taken with regard to cell types, culture medium and culture models, depending on the aim of the study. Although great strides have been made, there is still a need for further optimization, and optimally also for standardization, in order for in vitro co-culture models to become powerful tools in the discovery of key molecules dictating immunity and/or tolerance, and for understanding the complex interplay that takes place between mucosa, airway epithelium and resident or infiltrating immune cells. This review focuses on current knowledge and the advantages and limitations of the different cell types and culture methods used in co-culture models of the human airways.

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Abstract: The fluxes of mannitol, TRH, dexamethasone, FD-4, FD-10 and FD-20 across the Caco-2 monolayer were significantly enhanced when electric field was applied. The iontophoretic effect appeared to be directly upon tight junctions

Cited by 39 publications

References 14 publications

Dexamethasone–pDMAEMA polymeric conjugates reduce inflammatory biomarkers in human intestinal epithelial monolayers

Dexamethasone–pDMAEMA polymeric conjugates reduce inflammatory biomarkers in human intestinal epithelial monolayers

Anti‐proliferative effect of rhein, an anthraquinone isolated from Cassia species, on Caco‐2 human adenocarcinoma cells

Polarized Airway Epithelial Models for Immunological Co-Culture Studies

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