Sotirios G. Zarogiannis

Ascorbate and Deferoxamine Administration after Chlorine Exposure Decrease Mortality and Lung Injury in Mice

Chlorine (Cl(2)) gas exposure poses an environmental and occupational hazard that frequently results in acute lung injury. There is no effective treatment. We assessed the efficacy of antioxidants, administered after exposure, in decreasing mortality and lung injury in C57BL/6 mice exposed to 600 ppm of Cl(2) for 45 minutes and returned to room air. Ascorbate and deferoxamine were administered intramuscularly every 12 hours and by nose-only inhalation every 24 hours for 3 days starting after 1 hour after exposure. Control mice were exposed to Cl(2) and treated with vehicle (saline or water). Mortality was reduced fourfold in the treatment group compared with the control group (22 versus 78%; P = 0.007). Surviving animals in the treatment group had significantly lower protein concentrations, cell counts, and epithelial cells in their bronchoalveolar lavage (BAL). Lung tissue ascorbate correlated inversely with BAL protein as well as with the number of neutrophils and epithelial cells. In addition, lipid peroxidation was reduced threefold in the BAL of mice treated with ascorbate and deferoxamine when compared with the control group. Administration of ascorbate and deferoxamine reduces mortality and decreases lung injury through reduction of alveolar-capillary permeability, inflammation, and epithelial sloughing and lipid peroxidation.

Phenotypes of comorbidity in OSAS patients: combining categorical principal component analysis with cluster analysis

Phenotyping obstructive sleep apnea syndromes comorbidity has been attempted for the first time only recently. The aim of our study was to determine phenotypes of comorbidity in obstructive sleep apnea syndrome patients employing a data‐driven approach. Data from 1472 consecutive patient records were recovered from our hospitals database. Categorical principal component analysis and two‐step clustering were employed to detect distinct clusters in the data. Univariate comparisons between clusters included one‐way analysis of variance with Bonferroni correction and chi‐square tests. Predictors of pairwise cluster membership were determined via a binary logistic regression model. The analyses revealed six distinct clusters: A, ‘healthy, reporting sleeping related symptoms’; B, ‘mild obstructive sleep apnea syndrome without significant comorbidities’; C1: ‘moderate obstructive sleep apnea syndrome, obesity, without significant comorbidities’; C2: ‘moderate obstructive sleep apnea syndrome with severe comorbidity, obesity and the exclusive inclusion of stroke’; D1: ‘severe obstructive sleep apnea syndrome and obesity without comorbidity and a 33.8% prevalence of hypertension’; and D2: ‘severe obstructive sleep apnea syndrome with severe comorbidities, along with the highest Epworth Sleepiness Scale score and highest body mass index’. Clusters differed significantly in apnea–hypopnea index, oxygen desaturation index; arousal index; age, body mass index, minimum oxygen saturation and daytime oxygen saturation (one‐way analysis of variance P < 0.0001). Binary logistic regression indicated that older age, greater body mass index, lower daytime oxygen saturation and hypertension were associated independently with an increased risk of belonging in a comorbid cluster. Six distinct phenotypes of obstructive sleep apnea syndrome and its comorbidities were identified. Mapping the heterogeneity of the obstructive sleep apnea syndrome may help the early identification of at‐risk groups. Finally, determining predictors of comorbidity for the moderate and severe strata of these phenotypes implies a need to take these factors into account when considering obstructive sleep apnea syndrome treatment options.

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°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 &OHgr;H cm2 and a subsequent value persistence (p < 0.05); added basolaterally (n = 6), it increased the RTM to 22.66 ± 0.59 &OHgr;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 &OHgr;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 ribavirin and oseltamivir in reducing mortality and lung injury in mice infected with mouse adapted A/California/04/2009 (H1N1).

AIM To compare the efficacy of ribavirin and oseltamivir in reducing mortality, lung injury and cytokine response profile in pandemic influenza H1N1 (2009) infection. MAIN METHODS We assessed survival, weight loss, lung viral load (by RT-PCR), lung injury (by protein content in bronchoalveolar lavage), and inflammation (cell counts, differentials and cytokines in the bronchoalveolar lavage) in BALB/c mice after infection with mouse-adapted pandemic influenza strain A/California/04/2009. KEY FINDINGS Our results indicate that ribavirin (80 mg kg(-1)) and oseltamivir (50 mg kg(-1)) are equally effective in improving survival (100% vs. 0% in water treated controls), while ribavirin proved to be more effective in significantly preventing weight loss. Both drugs diminished the injury of the alveolar-capillary barrier by decreasing the protein detected in the BAL to baseline levels, and they were also equally effective in reduction lung viral loads by 100-fold. Administration of either drug did not decrease the amount of inflammatory infiltrate in the lung, but ribavirin significantly reduced the percentage comprised of lymphocytes. This study shows that these antivirals differentially regulate inflammatory cytokines and chemokines with ribavirin significantly reducing most of the cytokines/chemokines measured. Ribavirin treatment leads to a Th1 cytokine response while oseltamivir leads to a Th2 cytokine response with significant increase in the levels of the anti-inflammatory cytokine IL-10. SIGNIFICANCE This study reveals new mechanistic insights in the way that ribavirin and oseltamivir exert their antiviral activity and supports the theory that ribavirin could potentially serve as an efficacious therapeutic alternative for oseltamivir resistant pandemic H1N1 strains.

Physiology of pericardial fluid production and drainage

The pericardium is one of the serosal cavities of the mammals. It consists of two anatomical structures closely connected, an external sac of fibrous connective tissue, that is called fibrous pericardium and an internal that is called serous pericardium coating the internal surface of the fibrous pericardium (parietal layer) and the heart (visceral layer) forming the pericardial space. Between these two layers a small amount of fluid exists that is called pericardial fluid. The pericardial fluid is a product of ultrafiltration and is considered to be drained by lymphatic capillary bed mainly. Under normal conditions it provides lubrication during heart beating while the mesothelial cells that line the membrane may also have a role in the absorption of the pericardial fluid along with the pericardial lymphatics. Here, we provide a review of the the current literature regarding the physiology of the pericardial space and the regulation of pericardial fluid turnover and highlight the areas that need to be further investigated.

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 (RTM), 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 RTM 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.

Postexposure aerosolized heparin reduces lung injury in chlorine-exposed mice

Chlorine (Cl2) is a highly reactive oxidant gas that, when inhaled, may cause acute lung injury culminating in death from respiratory failure. In this study, we tested the hypothesis that exposure of mice to Cl2 causes intra-alveolar and systemic activation of the coagulation cascade that plays an important role in development of lung injury. C57Bl/6 mice were exposed to Cl2 (400 for 30 min or 600 ppm for 45 min) in environmental chambers and then returned to room air for 1 or 6 h. Native coagulation (NATEM) parameters such as blood clotting time and clot formation time were measured in whole blood by the viscoelastic technique. D-dimers and thrombin-anti-thrombin complexes were measured in both plasma and bronchoalveolar lavage fluid (BALF) by ELISA. Our results indicate that mice exposed to Cl2 gas had significantly increased clotting time, clot formation time, and D-dimers compared with controls. The thrombin-anti-thrombin complexes were also increased in the BALF of Cl2 exposed animals. To test whether increased coagulation contributed to the development of acute lung injury, mice exposed to Cl2 and returned to room air were treated with aerosolized heparin or vehicle for 20 min. Aerosolized heparin significantly reduced protein levels and the number of inflammatory cells in the BALF at 6 h postexposure. These findings highlight the importance of coagulation abnormities in the development of Cl2-induced lung injury.

Effect of adrenaline on transmesothelial resistance of isolated sheep pleura.

The effect of adrenaline on the transmesothelial resistance (RTM) of sheeps 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 viscerals one, suggesting differences in the distribution of the adrenergic receptors between the visceral and parietal pleura.

Gene expression profile of aquaporin 1 and associated interactors in malignant pleural mesothelioma

Overexpression of AQP1 has recently been shown to be an independent prognostic factor in pleural mesothelioma favoring survival. This paper presents a data mining and bioinformatics approach towards the evaluation of the gene expression profile of AQP1 in malignant pleural mesothelioma and of AQP1 associated markers in the context of mesothelioma disease phenotype, CDKN2A gene deletion, sex and asbestos exposure. The data generated were thus again subjected to differential expression profile analysis. Here we report that AQP1 is overexpressed in epithelioid mesothelioma and identify TRIP6 and EFEMP2 as candidate genes for further investigation in mesothelioma.

Nocturnal Hypertension Is Associated with an Exacerbation of the Endothelial Damage in Preeclampsia

Background: Non-dipping pattern of circadian blood pressure in preeclampsia is associated with an increased risk of cardiovascular disease. The pathogenetic mechanisms of this relationship are still unclear. We investigated whether non-dipping in preeclampsia could relate to endothelial activation or damage. Methods: Participants, 20 women with normal pregnancy (mean age 29.9 ± 5.7 years) and 31 women with preeclampsia (mean age 29.1 ± 5.1 years), un- derwent 24-hour ambulatory blood pressure monitoring. Plasma levels of von Willebrand factor (vWf), marker of endothelial damage and of soluble adhesion molecules (sVCAM-1, sICAM-1), and markers of endothelial activation were determined using commercially available enzyme-linked immunoassays. Results: Based on whether the nocturnal mean arterial pressure (MAP) relative to the daytime MAP declined by less than 10%, 21 women with preeclampsia were categorized as non-dippers. Compared to healthy pregnant women, patients with preeclampsia showed significantly enhanced levels of vWf (206.9 ± 40.6 vs. 123 ± 24 IU/dl;p<0.01) and sVCAM-1 (2,269 ± 426 vs.1,159.8 ± 340 ng/ml; p < 0.01). In addition, significantly higher levels of vWf (224.5 ± 34.9 vs. 170 ± 23 IU/dl; p < 0.01) and sVCAM-1 (2,405 ± 421.4 vs. 1,983 ± 276.7 ng/ml; p = 0.007) were determined, when women with preeclampsia and nocturnal hypertension (non-dippers) were compared to dippers. The results were similar even after adjustment for severity of preeclampsia. In contrast, neither preeclampsia nor dipping status had an effect on sICAM-1 levels. Conclusion: Nocturnal hypertension in preeclampsia is associated with elevated levels of molecules related to endothelial damage. Endothelial damage is a recognized pathogenetic factor for atherosclerosis and history of preeclampsia is a risk factor for cardiovascular disease. In this context, possible clinical im-plications of our findings deserve further investigation.