Rapid effects of 17beta-estradiol and progesterone on sheep visceral and parietal pleurae via a nitric oxide pathway

The role of nitric oxide in pleural disease

Nitric oxide (NO) regulates various physiological and pathophysiological functions in the lungs. However, there is much less information about the effects of NO in the pleura. The present review aimed to explore the available evidence regarding the role of NO in pleural disease. NO, has a double-edged role in the pleural cavity. It is an essential signaling molecule mediating various physiological cell functions such as lymphatic drainage of the serous cavities, the immune response to intracellular multiplication of pathogens, and downregulation of neutrophil migration, but also induces genocytotoxic and mutagenic effects when present in excess. NO is implicated in the pathogenesis of asbestos-related or exudative pleural disease and mesothelioma. From a clinical point of view, the fraction of exhaled NO has been suggested as a potential non-invasive tool for the diagnosis of benign asbestos-related disorders. Under experimental conditions, NO-mimetics were found to attenuate hypoxia-induced therapy resistance in mesothelioma. Similarly, hybrid agents consisting of an NO donor coupled with a parent anti-inflammatory drug showed an enhancement of the anti-inflammatory activity of anti-inflammatory drugs. However, given the paucity of research work performed over the last years in this area, further research should be undertaken to establish reliable conclusions with respect to the feasibility of determining or targeting the NO signaling pathway for pleural disease diagnosis and therapeutic management.

Estrogen receptor-alpha isoforms are the main estrogen receptors expressed in non-small cell lung carcinoma

The expression profile of estrogen receptors (ER) in Non-Small Cell Lung Carcinoma (NSCLC) remains contradictory. Here we investigated protein and transcriptome expression of ERα wild type and variants. Tissue Micro-Arrays of 200 cases of NSCLC (paired tumor/non-tumor) were assayed by immunohistochemistry using a panel of ERα antibodies targeting different epitopes (HC20, 6F11, 1D5, ERα36 and ERα17p). ERβ epitopes were also examined for comparison. In parallel we conducted a probe-set mapping (Affymetrix HGU133 plus 2 chip) meta-analysis of 12 NSCLC tumor public transcriptomic studies (1418 cases) and 39 NSCLC cell lines. Finally, we have investigated early transcriptional effects of 17β-estradiol, 17β-estradiol-BSA, tamoxifen and their combination in two NSCLC cell lines (A549, H520). ERα transcript and protein detection in NSCLC specimens and cell lines suggests that extranuclear ERα variants, like ERα36, prevail, while wild-type ERα66 is minimally expressed. In non-tumor lung, the wild-type ERα66 is quasi-absent. The combined evaluation of ERα isoform staining intensity and subcellular localization with sex, can discriminate NSCLC subtypes and normal lung. Overall ERα transcription decreases in NSCLC. ERα expression is sex-related in non-tumor tissue, but in NSCLC it is exclusively correlating with tumor histologic subtype. ERα isoform protein expression is higher than ERβ. ERα isoforms are functional and display specific early transcriptional effects following steroid treatment. In conclusion, our data show a wide extranuclear ERα-variant expression in normal lung and NSCLC that is not reported by routine pathology ER evaluation criteria, limited in the nuclear wild type receptor.

Design considerations and challenges for mechanical stretch bioreactors in tissue engineering

With the increase in average life expectancy and growing aging population, lack of functional grafts for replacement surgeries has become a severe problem. Engineered tissues are a promising alternative to this problem because they can mimic the physiological function of the native tissues and be cultured on demand. Cyclic stretch is important for developing many engineered tissues such as hearts, heart valves, muscles, and bones. Thus a variety of stretch bioreactors and corresponding scaffolds have been designed and tested to study the underlying mechanism of tissue formation and to optimize the mechanical conditions applied to the engineered tissues. In this review, we look at various designs of stretch bioreactors and common scaffolds and offer insights for future improvements in tissue engineering applications. First, we summarize the requirements and common configuration of stretch bioreactors. Next, we present the features of different actuating and motion transforming systems and their applications. Since most bioreactors must measure detailed distributions of loads and deformations on engineered tissues, techniques with high accuracy, precision, and frequency have been developed. We also cover the key points in designing culture chambers, nutrition exchanging systems, and regimens used for specific tissues. Since scaffolds are essential for providing biophysical microenvironments for residing cells, we discuss materials and technologies used in fabricating scaffolds to mimic anisotropic native tissues, including decellularized tissues, hydrogels, biocompatible polymers, electrospinning, and 3D bioprinting techniques. Finally, we present the potential future directions for improving stretch bioreactors and scaffolds. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:543-553, 2016.

Endothelin-1 acutely reduces the permeability of visceral sheep peritoneum in vitro through both endothelin-A and endothelin-B receptors

Mesothelium is an important part of the peritoneal barrier for water and ion transport, essential for effective peritoneal dialysis (PD). Peritoneal fibrosis has been associated with PD treatment failure. Endothelin-1 (ET-1) is a potent vasoactive peptide, involved in pathologic fibrotic processes. Its action is mediated mainly by endothelin type A (ETA ) and type B (ETB ) receptors. The aim of this study was to investigate, by Ussing chamber experiments, the effect of ET-1 on the transmesothelial electrical resistance (RTM ) of the isolated visceral sheep peritoneum. Intact sheets of visceral peritoneum were obtained from 40 adult sheep and mounted in Ussing-type chambers. ET-1 (10(-7)  M), BQ-123 (ETA receptor antagonist; 10(-6)  M), BQ-788 (ETB receptor antagonist; 10(-6)  M), and their combinations were added on the apical and the basolateral side of the peritoneum. RTM was measured before and serially after addition of the substances, and changes were registered as percentage (ΔRTM %). RTM increased within 1 min after addition of ET-1 apically (ΔRTM 65.03 ± 15.87%; P < 0.05) or basolaterally (ΔRTM 85.5 ± 20.86%; P < 0.05). BQ-123 and BQ-788 and their combination significantly reduced (P < 0.05) the effect of ET-1 to a similar degree in all cases. These results clearly indicate that ET-1 reduces ionic permeability of the visceral sheep peritoneum in vitro. Additionally, it is obvious that this inhibitory effect is mediated through both ETA and ETB receptors.

Evidence for non genomic action of 17β estradiol on transepithelial resistance of human fetal membranes

BACKGROUND

The role of hormones in the transport mechanisms of human fetal membranes in pregnancy is unclear. Estrogens are essential hormones in pregnancy and they play an important role in the ion transport via membranes.

AIM

The aim of this study was to investigate the effect of 17β-estradiol on transepithelial electrical resistance in the human amniochorion.

MATERIAL AND METHODS

Specimens of human fetal membranes were obtained. 17β-estradiol, tamoxifen and their combination were added in an Ussing chamber. Transepithelial resistance was measured before and after the addition of each solution.

RESULTS

An increase in transepithelial resistance was seen after the addition of estradiol to both sides of the membranes. The effect was rapid with a peak at the 1st min of application and dose-depended. Tamoxifen, caused a similar effect but smaller in magnitude and shorter in duration. Tamoxifen in combination with estradiol inhibited only in part the action of estradiol.

CONCLUSIONS

These results suggest that estradiol induces a rapid increase of transepithelial resistance in human fetal membranes in vitro via a non-genomic pathway. It is possible those changes in transepithelial resistance play a role in the control of permeability of human amniochorion.

Dexamethasone decreases the transmesothelial electrical resistance of the parietal and visceral pleura

The effect of dexamethasone on the transmesothelial electrical resistance (R(TM)) of sheep pleura was investigated by Ussing chamber experiments. Our results show that dexamethasone decreases the R(TM) of sheep pleurae, in part by stimulation of glucocorticoid receptors. This finding may be of importance in regard to the faster resolution of corticosteroid-treated pleural effusions.

Rapid effect of progesterone on transepithelial resistance of human fetal membranes: evidence for non-genomic action

1. The 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 (R(TE)) in the human amniochorion. 2. Fetal 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 R(TE) was measured before and 1, 5, 10, 15, 20, 25, 30, 45 and 60 min after each solution was added (at 37 degrees C). The R(TE) was calculated in Omega.cm(2), according to Ohm's law. 3. The mean (+/-SEM) basal value of R(TE) before the application of any substance in all experiments was 29.1 +/- 0.4 Omega.cm(2). The net change in the R(TE) (Delta R(TE)) 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 R(TE) 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 Delta R(TE) during the 1st min on the fetal side was seen with the combination of progesterone plus mifepristone (4.0 +/- 0.3 Omega.cm(2)) and the lowest Delta R(TE) occurred with mifepristone (1.5 +/- 0.1 Omega.cm(2)). 4. The present results demonstrated that the R(TE) of human fetal membranes increases rapidly in response to progesterone. It is possible that changes in R(TE) play a role in the control of membrane permeability during pregnancy.

Amiloride-sensitive sodium channels on the parietal human peritoneum: evidence by ussing-type chamber experiments

The mesothelium is part of the peritoneal water and ion transport barrier essential for peritoneal dialysis (PD) treatment and has a central role in the pathogenesis of peritoneal fibrosis and ultrafiltration failure observed in many PD patients. We investigated the effect of amiloride on the transmesothelial electrical resistance (RTM) of isolated parietal human peritoneum. Intact sheets were obtained from seven patients (three men, four women; mean age, 64 +/- 8 years). Fourteen peritoneal planar sheets were transferred to the laboratory in oxygenated Krebs-Ringer bicarbonate solution at 4 degrees C within 30 minutes after removal and mounted in an Ussing-type chamber. Amiloride (10(-3) mol/L) added apically (n = 8) caused a rapid rise of the RTM to 24.15 +/- 0.76 [OMEGA]H cm2 and a subsequent value persistence (p < 0.05); added basolaterally (n = 6), it increased the RTM to 22.66 +/- 0.59 [OMEGA]H cm2 within 1 minute, which persisted throughout the experiment. RTM was measured before and serially for 30 minutes after addition of amiloride. Control RTM was 20.29 +/- 0.86 [OMEGA]H cm2. These results indicate a rapid inhibitory effect of amiloride on the ionic permeability of parietal human peritoneum. The increase in the RTM observed after addition of amiloride clearly indicates the existence of amiloride-sensitive sodium channels on the human parietal peritoneal membrane, which may play some role in the ultrafiltration process and sodium removal during PD.

Comparison of the electrophysiological properties of the sheep isolated costal and diaphragmatic parietal pleura

1. Pleural permeability may contribute to pleural fluid turnover. The transmesothelial resistance (R(TM)), is an established surrogate of mesothelial permeability. The aim of the present study was to compare the electrophysiological properties of costal and diaphragmatic parietal pleura. 2. Specimens of the parietal pleura were isolated from 12 adult sheep from the chest wall and the diaphragm. Electrophysiological measurements were conducted with the Ussing system. Specimens of the parietal pleura of both types (diaphragmatic and costal) were compared histologically and total protein content measurements were also made. 3. The R(TM) of the diaphragmatic parietal pleura was significantly higher than that of the costal parietal pleura throughout the experiment. The diaphragmatic parietal pleura contains more cuboidal cells than the costal parietal pleura and its protein content was higher, however this difference was not statistically significant. 4. The costal parietal pleura consists of a more 'leaky' mesothelium than the diaphragmatic pleura. The morphological differences between the two types of parietal pleura may underline the electrophysiological findings.

The contribution of ascorbic acid and dehydroascorbic acid to the protective role of pleura during inflammatory reactions

It is well-known that parapneumonic effusions lead to the formation of inflammatory exudates which contain an increasing amount of inflammatory cells, especially polymorphonuclear. At these pathological conditions characterized by oxidative stress, ascorbic acid (AA) plays an important role in quenching free radicals, so that it could protect neutrophils and mesothelial cells from oxidative damage. Besides that ascorbic acid and its metabolite dehydroascorbic acid (DHA) alters the sheep visceral and parietal pleura permeability. More specific ascorbic acid as well as dehydroascorbic acid decreases the permeability of pleura after addition on apical and basolateral side in both visceral and parietal pleurae. It seems that, AA and DHA have an opposite action upon pleura from that of the inflammatory mediators, like VEGF, which increases the permeability of pleura and causes mesothelial barrier dysfunction. The decrease of pleura permeability induced by AA and DHA suggest the hypothesis that AA and/or its metabolite DHA during inflammatory reactions not only protects mesothelial cells from oxidative damage, but also contributes to maintaining the mesothelial barrier function. Consequently, the inflammatory pleural fluid may be trapped in pleural space and the inflammation may be restricted, and have extension avoided.

Effect of adrenaline on transmesothelial resistance of isolated sheep pleura

The effect of adrenaline on the transmesothelial resistance (RTM) of sheep's visceral and parietal pleura was studied using the Ussing chamber technique. Basal transmesothelial resistance of visceral pleura was found to be 20.71 +/- 0.31 Omega cm2, whereas that of parietal pleura was found to be 19.53 +/- 0.34 Omega cm2. Immediately after the addition of adrenaline (10(-7) M) both apically and basolaterally on the visceral and parietal pleura, these values were significantly increased (P < 0.05). Addition of the nonselective beta-receptor blocker, propranolol (10(-5) M), suppressed this effect in both visceral and parietal pleura, while addition of the nonselective alpha-receptor blocker, phentolamine (10(-5) M), partly suppressed the above-mentioned increase in the parietal pleura. In conclusion, our results show that adrenaline has a rapid effect on both pleurae. This rapid effect is mediated by the stimulation of beta-adrenergic receptors in the case of visceral pleura, while in the case of parietal pleura this effect seems to be due to a stimulation of alpha- and beta-adrenergic receptors. On the visceral pleura the effect of adrenaline vanishes after some minutes and on the parietal this effect is more permanent than the visceral's one, suggesting differences in the distribution of the adrenergic receptors between the visceral and parietal pleura.

mu-Opioid influence on transmesothelial resistance of isolated sheep pleura and parietal pericardium

The effect of morphine (mu-opioid receptor agonist) on the transmesothelial resistance (R(TM)) of sheep's pleura and parietal pericardium was studied using the Ussing chamber technique. Basal transmesothelial resistance of parietal pleura was found to be 19.57+/-0.32 Omega cm2 and of visceral pleura was found to be 19.41+/-0.31 Omega cm2, whereas that of parietal pericardium was found to be 22.83+/-0.4 Omega cm2. Immediately after the addition of morphine (10(-9) M) both apically and basolaterally on the parietal pleura and parietal pericardium, these values were significantly increased (P<0.05). On the contrary, addition of morphine (10(-9) M) resulted in a rapid increase, only when placed basolaterally on the visceral pleura (P<0.05). In conclusion, our findings suggest that morphine, probably through mu-opioid stimulation, increases in vitro the transmesothelial resistance of the parietal pleura, of the visceral pleura when added basolaterally and of the parietal pericardium.

Enhancement of the Transmesothelial Resistance of the Parietal Sheep Peritoneum by Epinephrine In Vitro: Ussing-type Chamber Experiments

The peritoneal mesothelium constitutes an ion transport barrier that is taken advantage of in peritoneal dialysis. The aim of this study was to investigate the effects of epinephrine on the electrical transmesothelial resistance (R(TM)) of the isolated parietal sheep peritoneum by means of Ussing-type chamber experiments. Intact parietal (diaphragmatic) peritoneal samples were obtained from adult sheep immediately after sacrifice and transferred within 0.5 h to the laboratory in a cooled Krebs-Ringer bicarbonate solution (4 degrees C, pH 7.5), bubbled with 95% O2-5% CO2. A parietal peritoneal planar sheet was mounted in a Ussing-type chamber. Epinephrine (10(-7) M) was added to the apical and the basolateral side. The R(TM) was measured before and serially after the addition of epinephrine for 30 min. As active ion transport is temperature-dependent, all measurements were performed at 37 degrees C. The results were calculated as means with standard errors (x +/- SE) of six independent experiments. The control R(TM) was 20.05 +/- 0.61 ohm x cm2. The addition of epinephrine to the basolateral side within 1 min induced an increase of R(TM) to 21.8 +/- 0.45 ohm x cm2, which decreased thereafter progressively to reach control values again after 15 min. A similar effect of epinephrine on the apical side was apparent with a rapid rise of R(TM) to 22.5 +/- 0.66 ohm x cm2 and a subsequent decrease (P < 0.05). A clear association between the R(TM) and active ion transport was established from previous studies. The results of our study indicate a rapid action of epinephrine on the parietal peritoneum permeability.

Functional similarities between pleura and the renal proximal tubule – membrane and cellular considerations

The small amount of liquid that, under physiological conditions, is presented in the pleural cavity has been the focus of extensive research for more than a century. However, there are still unanswered questions and considerable controversies about the nature of the forces governing its movement into and out of the pleural cavity. Early in the 20th century has been proposed that pleural fluid turnover is simple based on the balance between hydraulic and colloid osmotic pressures existing across the pleural membranes. This original hypothesis has not been validated by data accumulating over the last 20 years. Pleural tissues and renal proximal tubules present high water permeability, small transepithelial electrical resistance (22.02 Omega cm2) and the same cation transportation such as Na+ channels, Na+-K+ ATPase channels, and Na+-H+ exchanger. In contrast to previous conflicting theories concerning pleura fluid movement, the same functional characteristics suggest the hypothesis that physiology of pleura is similar to proximal tubules.