Acid is a major cause of gastro-esophageal reflux disease. However, the influence of acid on the esophageal stratified epithelial barrier function and tight junction (TJ) proteins is not fully understood. Here, we explore the influence of acid on barrier function and TJ proteins using a newly developed model of the esophageal-like squamous epithelial cell layers that employs an air-liquid interface (ALI) system. Barrier function was determined by measuring trans-epithelial electrical resistance (TEER) and diffusion of paracellular tracers. TJ-related protein (claudin-1, claudin-4, occludin and ZO-1) expression and localization was examined by immunofluorescent staining, and by western blotting of 1% NP-40 soluble and insoluble fractions. We also examined the influence of acid (pH 2-4) on the barrier created by these cells. The in vitro ALI culture system showed a tight barrier (1500-2500 O . cm 2 ) with the expression of claudin-1, claudin-4, occludin and ZO-1 in the superficial layers. Claudin-1, claudin-4, occludin and ZO-1 were detected as dots and whisker-like lines in the superficial layers, and as a broad line in the suprabasal layers. These localization patterns are similar to those in the human esophagus. On day 7 under ALI culture, TJ proteins were detected in the superficial layers with functional properties, including decreased permeability and increased TEER. Dilated intercellular spaces were detected at the suprabasal cell layers even under the control conditions of ALI cells. pH 2 acid on the apical side significantly reduced the TEER in ALI-cultured cells. This decrease in TEER by the acid was in parallel with the decreased amount of detergent-insoluble claudin-4. Claudin-4 delocalization was confirmed by immunofluorescent staining. In conclusion, TJs are located in the superficial layers of the esophagus, and acid stimulation disrupts barrier function, at least in part by modulating the amount and localization of claudin-4 in the superficial layers.

rent experimental models of esophageal epithelium in vitro suffer from either poor differentiation or complicated culture systems. We have established a model to study stratified squamous epithelium in vitro, which is very similar to esophageal epithelium in vivo. A stratified squamous multilayer epithelium was formed by seeding primary normal human bronchial epithelial (NHBE) cells onto collagen-and fibronectin-coated trans-well inserts and then cultivating the cells under air-liquid interface (ALI) conditions in the presence of growth factors and low levels of all-trans-retinoic acid. Trans-epithelial electrical resistance (TEER) measurements revealed the presence of a tight barrier, previously only achievable with esophageal biopsies mounted in Ussing chambers. Molecular markers for desmosomes, cornified envelope, tight junctions, and mature esophageal epithelium were upregulated in the differentiating culture in parallel with functional properties, such as decreased permeability and acid resistance and restoration. Acid exposure resulted in a decrease in TEER, but following 1-h recovery the TEER values were fully restored. Treatment with all-trans-retinoic acid decreased TEER and inhibited the recovery after acid challenge. PPAR-delta agonist treatment increased TEER, and this temporary increase in TEER was consistent with an increase in involucrin mRNA. Global gene expression analysis showed that ALI-differentiated NHBE cells had expression profiles more similar to epithelial biopsies from the esophageal tissue of healthy volunteers than to any other cell line. With respect to morphology, molecular markers, barrier properties, and acid resistance, this model presents a new way to investigate barrier properties and the possible effects of different agents on human esophagus-like epithelium. esophageal epithelium; acid; barrier function; air-liquid interface ONE OF THE PRIMARY FUNCTIONS of the esophageal epithelium is to protect the underlying tissue against mechanical and chemical insult. The epithelium of the distal esophagus also needs to withstand reflux from the stomach, which contains acid, bile, and proteases. Failure of the epithelium to protect the underlying tissue from these attacks results in erosion, esophagitis, and painful symptoms. The esophagus is covered by a nonkeratinized stratified squamous epithelium. The keratinocytes in a non-keratinized squamous epithelium can be assigned to three layers with distinct features, namely the basal, intermediate, and superficial layers (1), of which the epithelial barrier properties reside in the upper intermediate and superficial layers.Different cell lines and primary cells are available to use as esophageal epithelial cell models. Het-1A, an immortalized normal human esophageal cell line (28), grows as a monolayer. Kyse-140 and Kyse-510 are esophageal carcinoma cell lines that also grow as monolayers. The TR146 cell line originates from human buccal epithelium (24) and has been shown to form a stratified epithelium (four to seven cell layers) and have ...

Growing interest has arisen regarding the mechanism of dyspeptic symptom generation. However, no evaluation system of these symptoms in animals has been developed. In this study, we examined whether voluntary movement of rats could be a measure to assess visceral symptoms of reflux oesophagitis. A chronic acid reflux oesophagitis model was made using rats, and the size of erosions was measured. Omeprazole was administered to the oesophagitis rats for 10 days. The amount of voluntary movement was measured by an infrared sensor. Intracellular spaces in oesophageal epithelium were also measured using a emission electron microscope. NP-40 soluble and insoluble fractions of claudins were examined by Western blot. Voluntary movement was significantly lower in the oesophagitis model rats than in the sham-operated rats (P < 0.01). Although omeprazole reduced the size of erosions, it did not significantly affect the total amount of voluntary movement (r = -0.033, P = 0.916). Intracellular spaces were significantly dilated in the oesophagitis model rats and claudin-3 showed a significantly lower relative quantity in the NP-40 insoluble fraction. Omeprazole significantly increased voluntary movement of oesophagitis model rats and the relative quantity of claudin-3 in the insoluble fraction (P < 0.05). Dilated intercellular spaces and the lower level of claudin-3 may relate to the voluntary movement of oesophagitis model rats. Decreases in voluntary movement of oesophagitis model rats may reflect visceral symptoms and be able to serve as an index of chronic abdominal symptoms.

Rikkunshito increased voluntary movement in RE model rats. This may have been because rikkunshito ameliorated the symptoms of RE by improving the barrier function of esophageal mucosa.

IntroductionFlavonoids are converted to inactive metabolites like glucuronides in the gut, and circulate mainly as glucuronides in blood stream, resulting in low concentrations of active aglycones in plasma. It is therefore unclear how oral flavonoids exert their effects in tissues. We recently reported the plasma pharmacokinetics of some flavonoids and suggested the possibility that the absorbed flavonoids modified macrophage functions leading to enhance bacterial clearance. We aimed to confirm their pharmacological profiles focusing on tissue macrophages.MethodsPseudoinfection was induced by intradermal injection of FITC‐conjugated and killed Staphylococcus aureus into the ears of mice treated with or without genistein 7‐O‐glucuronide (GEN7G, 1 mg/kg, i.v.). FACS analysis was performed on single cell suspensions dispersed enzymatically from the skin lesions at 6 h post pseudoinfection to evaluate phagocytic activities of monocytes/macrophages (CD11b+Ly6G−) and neutrophils (CD11b+Ly6G+). Phagocytosis of the FITC‐conjugated bacteria by four glucuronides including GEN7G was evaluated in cultures of mouse macrophages.ResultsAfter GEN7G injection, genistein was identified in the inflamed ears as well as GEN7G, and the phagocytic activity of CD11b+Ly6G− cells was increased. GEN7G was converted to genistein by incubation with macrophage‐related β‐glucuronidase. Macrophage culture assays revealed that GEN7G increased phagocytosis, and the action was dampened by a β‐glucuronidase inhibitor. Binding of aglycones to estrogen receptors (ERs), putative receptors of flavonoid aglycones, correlated to biological activities, and glucuronidation reduced the binding to ERs. An ER antagonist suppressed the increase of macrophage function by GEN7G, whereas estradiol enhanced phagocytosis as well.ConclusionsThis study suggests a molecular mechanism by which oral flavonoids are carried as glucuronides and activated to aglycones by β‐glucuronidase in tissue macrophages, and contributes to the pharmacological study of glucuronides.

Key Points• Psychological stress causes impaired gastric accommodation (GA), which is associated with early satiety in patients with functional dyspepsia. However, the mechanism by which stress inhibits GA remains unknown.• The aim of this study was to investigate the influence of stress on GA, and the involvement of 5-HT 2B receptors in the impairment of GA using an animal model.• After subjection to water-avoidance stress, GA in conscious guinea pigs was evaluated by measuring the intrabag pressure following administration of a liquid meal.• The present study revealed that GA was inhibited by stress, and that this inhibition was mediated by an increased responsiveness of 5-HT 2B receptors in the gastric fundus. AbstractBackground Psychological stress has been shown to impair gastric accommodation (GA), but its mechanism has not been elucidated. This study was conducted to clarify the role of 5-HT 2B receptors in a guinea pig model of stress-induced impairment of GA. Methods Gastric accommodation was evaluated by measuring the intrabag pressure in the proximal stomach after administration of a liquid meal. The guinea pigs were subjected to water-avoidance stress. The role of 5-HT 2B receptors in impairment of GA was investigated by administering a 5-HT 2B receptor agonist (BW723C86) or antagonist (SB215505), the traditional Japanese medicine rikkunshito (RKT), a muscarinic M 3 receptor antagonist (1,1-dimethyl-4-diphenylacetoxypiperidium iodide [4-DAMP]), or a nitric oxide synthase inhibitor (N x -nitro-L-arginine [L-NNA]). Key Results In normal animals, liquid meal-induced GA was inhibited by BW723C86, but was not affected by SB215505. The inhibition of GA by BW723C86 was reversed by co-administration of 4-DAMP. Compared to normal animals, GA in stressed animals was significantly inhibited. SB215505 and RKT significantly suppressed stress-induced impairment of GA. After meal administration, the level of cyclic guanosine monophosphate in gastric fundus tissue increased by approximately twofold in normal animals, but did not change in stressed animals. The inhibition of GA by L-NNA was suppressed by SB215505 or RKT. At a dose that did not affect GA in normal animals, BW723C86 exacerbated the impairment of GA in stressed animals. Conclusions and Inferences Stress-induced impairment of GA may be mediated by an increased responsiveness of 5-HT 2B receptors, and activation of the 5-HT 2B receptor signaling pathway may have an inhibitory effect on nitric oxide function.

Objective. Bokusoku (BK) is an extract from the Quercus cortex used in folk medicine for treatment of skin disorders and convergence, and is present in jumihaidokuto, a traditional Japanese medicine that is prescribed for purulent skin diseases like acne vulgaris. The excess of sebum production induced by androgen is involved in the development of acne. Our aim is to examine whether BK and its constituents inhibit testosterone metabolism and testosterone-induced sebum synthesis. Methods. Measurements of 5α-reductase activity and lipogenesis were performed using rat liver microsomes and hamster sebocytes, respectively. Results. BK dose-dependently reduced the conversion of testosterone to a more active androgen, dihydrotestosterone in a 5α-reductase enzymatic reaction. Twenty polyphenols in BK categorized as gallotannin, ellagitannin, and flavonoid were identified by LC-MS/MS. Nine polyphenols with gallate group, tetragalloyl glucose, pentagalloyl glucose, eugeniin, 1-desgalloyl eugeniin, casuarinin, castalagin, stenophyllanin C, (−)-epicatechin gallate, and (−)-epigallocatechin gallate, inhibited testosterone metabolism. In particular, pentagalloyl glucose showed the strongest activity. BK and pentagalloyl glucose suppressed testosterone-induced lipogenesis, whereas they weakly inhibited the lipogenic action of insulin. Conclusions. BK inhibited androgen-related pathogenesis of acne, testosterone conversion, and sebum synthesis, partially through 5α-reductase inhibition, and has potential to be a useful agent in the therapeutic strategy of acne.

Most orally administered polyphenols are metabolized, with very little absorbed as aglycones and/or unchanged forms. Metabolic and pharmacokinetic studies are therefore necessary to understand the pharmacological mechanisms of polyphenols. Jumihaidokuto (JHT), a traditional Japanese medicine, has been used for treatment of skin diseases including inflammatory acne. Because JHT contains various types of bioactive polyphenols, our aim was to clarify the metabolism and pharmacokinetics of the polyphenols in JHT and identify active metabolites contributing to its antidermatitis effects. Orally administered JHT inhibited the increase in ear thickness in rats induced by intradermal injection of Propionibacterium acnes. Quantification by LC-MS/MS indicated that JHT contains various types of flavonoids and is also rich in hydrolysable tannins, such as 1,2,3,4,6-penta-O-galloyl glucose. Pharmacokinetic and antioxidant analyses showed that some flavonoid conjugates, such as genistein OPEN ACCESSMolecules 2015, 20 18032 7-O-glucuronide and liquiritigenin 7-O-glucuronide, appeared in rat plasma and had an activity to inhibit hydrogen peroxide-dependent oxidation. Furthermore, 4-O-methylgallic acid, a metabolite of Gallic acid, appeared in rat plasma and inhibited the nitric oxide reaction. JHT has numerous polyphenols; it inhibited dermatitis probably via the antioxidant effect of its metabolites. Our study is beneficial for understanding in vivo actions of orally administered polyphenol drugs.