Asiaticoside inhibits TNF-alpha-induced endothelial hyperpermeability of human aortic endothelial cells

The increase in endothelial permeability often promotes edema formation in various pathological conditions. Tumor necrosis factor-alpha (TNF-α), a pro-atherogenic cytokine, impairs endothelial barrier function and causes endothelial dysfunction in early stage of atherosclerosis. Asiaticoside, one of the triterpenoids derived from Centella asiatica, is known to possess antiinflammatory activity. In order to examine the role of asiaticoside in preserving the endothelial barrier, we assessed its effects on endothelial hyperpermeability and disruption of actin filaments evoked by TNF-α in human aortic endothelial cells (HAEC). TNF-α caused an increase in endothelial permeability to fluorescein isothiocyanate (FITC)-dextran. Asiaticoside pretreatment significantly suppressed TNF-α-induced increased permeability. Asiaticoside also prevented TNF-α-induced actin redistribution by suppressing stress fiber formation. However, the increased F to G actin ratio stimulated by TNF-α was not changed by asiaticoside. Cytochalasin D, an actin depolymerizing agent, was used to correlate the anti-hyperpermeability effect of asiaticoside with actin cytoskeleton. Surprisingly, asiaticoside failed to prevent cytochalasin D-induced increased permeability. These results suggest that asiaticoside protects against the disruption of endothelial barrier and actin rearrangement triggered by TNF-α without a significant change in total actin pool. However, asiaticoside seems to work by other mechanisms to maintain the integrity of endothelial barrier rather than stabilizing the F-actin organization

Asiatic acid stabilizes cytoskeletal proteins and prevents TNF-α-induced disorganization of cell-cell junctions in human aortic endothelial cells

Endothelial hyperpermeability represents an initiating step in early atherosclerosis and it often occurs as a result of endothelial barrier dysfunction. Asiatic acid, a major triterpene isolated from Centella asiatica (L.) Urban, has previously been demonstrated to protect against tumor necrosis factor (TNF)-α-induced endothelial barrier dysfunction. The present study aimed to investigate the mechanisms underlying the barrier protective effect of asiatic acid in human aortic endothelial cells (HAECs). The localization of F-actin, diphosphorylated myosin light chain (diphospho-MLC), adherens junctions (AJs) and tight junctions (TJs) was studied using immunocytochemistry techniques and confocal microscopy. Their total protein expressions were examined using western blot analysis. The endothelial permeability was assessed using In Vitro Vascular Permeability Assay kits. In addition, intracellular redistribution of the junctional proteins was evaluated using subcellular fractionation kits. We show that asiatic acid stabilized F-actin and diphospho-MLC at the cell periphery and prevented their rearrangement stimulated by TNF-α. However, asiatic acid failed to attenuate cytochalasin D-induced increased permeability. Besides, asiatic acid abrogated TNF-α-induced structural reorganization of vascular endothelial (VE)-cadherin and β-catenin by preserving their reticulum structures at cell-cell contact areas. In addition, asiatic acid also inhibited TNF-α-induced redistribution of occludin and zona occludens (ZO)-1 in different subcellular fractions. In conclusion, the barrier-stabilizing effect of asiatic acid might be associated with preservation of AJs and prevention of TJ redistribution caused by TNF-α. This study provides evidence to support the potential use of asiatic acid in the prevention of early atherosclerosis, which is initiated by endothelial barrier dysfunction

Cryptotanshinone inhibits TNF-α-induced early atherogenic events in vitro

Endothelial dysfunction has been implicated in the pathogenesis of atherosclerosis. Salvia miltiorrhiza (danshen) is a traditional Chinese medicine that has been effectively used to treat cardiovascular disease. Cryptotanshinone (CTS), a major lipophilic compound isolated from S. miltiorrhiza, has been reported to possess cardioprotective effects. However, the anti-atherogenic effects of CTS, particularly on tumor necrosis factor-α (TNF-α)-induced endothelial cell activation, are still unclear. This study aimed to determine the effect of CTS on TNF-α-induced increased endothelial permeability, monocyte adhesion, soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), monocyte chemoattractant protein 1 (MCP-1) and impaired nitric oxide production in human umbilical vein endothelial cells (HUVECs), all of which are early events occurring in atherogenesis. We showed that CTS significantly suppressed TNF-α-induced increased endothelial permeability, monocyte adhesion, sICAM-1, sVCAM-1 and MCP-1, and restored nitric oxide production. These observations suggest that CTS possesses anti-inflammatory properties and could be a promising treatment for the prevention of cytokine-induced early atherogenesis

Barrier protective effect of asiatic acid in TNF-α-induced activation of human aortic endothelial cells

Background: Endothelial cell activation is characterized by increased endothelial permeability and increased expression of cell adhesion molecules (CAMs). This allows monocyte adherence and migration across the endothelium to occur and thereby initiates atherogenesis process. Asiatic acid is a major triterpene isolated from Centella asiatica (L.) Urban and has been shown to possess anti-oxidant, anti-hyperlipidemia and anti-inflammatory activities. Purpose: We aimed to investigate protective effects of asiatic acid on tumor necrosis factor-α (TNF-α)-induced endothelial cell activation using human aortic endothelial cells (HAECs). Study design: For cell viability assays, HAECs were treated with asiatic acid for 24 h. For other assays, HAECs were pretreated with various doses of asiatic acid (10–40 µM) for 6 h followed by stimulation with TNF-α (10 ng/ml) for 6 h. Methods: Fluorescein isothiocyanate (FITC)-dextran permeability assay was performed using commercial kits. Total protein expression of CAMs such as E-selectin, ICAM-1, VCAM-1 and PECAM-1 as well as phosphorylation of IκB-α were determined using western blot. The levels of soluble form of CAMs were measured using flow cytometry. Besides, we also examined the effects of asiatic acid on U937 monocyte adhesion and monocyte migration in HAECs using fluorescent-based assays. Results: Asiatic acid significantly suppressed endothelial hyperpermeability, increased VCAM-1 expression and increased levels of soluble CAMs (sE-selectin, sICAM-1, sVCAM-1 and sPECAM-1) triggered by TNF-α. Neither TNF-α nor asiatic acid affects PECAM-1 expression. However, asiatic acid did not inhibit TNF-α-induced increased monocyte adhesion and migration. Interestingly, asiatic acid suppressed increased phosphorylation of IκB-α stimulated by TNF-α. Conclusion: These results suggest that asiatic acid protects against endothelial barrier disruption and this might be associated with the inhibition of NF-κB activation. We have demonstrated a novel protective role of asiatic acid on endothelial function. This reveals the possibility to further explore beneficial effects of asiatic acid on chronic inflammatory diseases that are initiated by endothelial cell activation

Experimental review on the Substance P-enhanced endothelial permeability in human umbilical vein endothelial cells (HUVECS)

Inflammation is the immediate response to tissue damage or harmful stimuli. Though inconvenient, its role is significant and important as the protective and physiological response of our body. It directly sets the stage for tissue repair particularly increasing endothelial permeability which then contributes to the healing process. However, in some cases inflammation may progress out of control causing various inflammatory diseases. Neurogenic inflammation is a sub-set of inflammation and is characterized by an increase in neuronal chemical mediators such as Substance P (SP). In this study, we investigated the involvement of SP in enhancing endothelial permeability on HUVECs monolayer. Neurogenic inflammation was induced through the administration of SP (1 nM to 100 nM) on HUVECs monolayer inserts, and incubated with varying short (10, 20 and 30 minutes) and longer (6, 12 and 24 hours) time-points. FITC-Dextran were finally added to cell culture inserts for 5 minutes to let the fluorescence molecule pass through the gaps. Endothelial permeability is directly proportional with extravasation of FITC-Dextran, determined by fluorescence intensity reading. Based on our data, there were no significant differences between control group (non-treated cell) and the different concentrations of SP at different time-points. Our current findings suggest that SP was unable to increase the endothelial permeability on HUVECs monolayer inflammatory experimental model. Experiments that use this model to mimic vascular inflammation in laboratory settings may require further elucidation in the future

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Mechanisms of interferon-gamma (IFN-y)-induced hyperpermeability changes in human umbilical vein endothelial cells

Endothelial dysfunction, characterized by increased endothelial permeability, is the initiating step in the pathogenesis of vascular diseases such as atherosclerosis. Interferon-gamma (IFN-γ), a pro-inflammatory cytokine, has been reported to impair the endothelial barrier and thus, increases vascular permeability. However, the mechanism by which IFN-γ disrupts the endothelial barrier has never been clarified. Therefore, this study aimed to evaluate the underlying mechanisms of IFN-γ-induced hyperpermeability changes using human umbilical vein endothelial cells (HUVECs). HUVECs were used as a model system to study permeability changes because inflammatory events are commonly occurs in postcapillary venules in vivo. As a preliminary step, the HUVECs viability was determined using MTT and ATP assays. Permeability changes were assessed using in vitro permeability assay kits. Localization of F-actin, caldesmon, β-catenin and vascular endothelial cadherin (VE-cadherin) was studied using confocal microscope. Total protein expressions of β-catenin, VE-cadherin, F- /G-actin, p38 MAP kinase, phosphorylated-p38 MAP kinase (p-p38 MAP kinase), caldesmon and phosphorylated-caldesmon (p-caldesmon) were performed using Western blot analysis. Protein expressions of β-catenin and VE-cadherin in different cell compartments were studied using subcellular protein fractionation kit. The interactions of caldesmon to actin and myosin were studied using a co-immunoprecipitation assay. The levels of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were detected using Griess assay and enzyme-linked immunosorbent assay (ELISA), respectively. The present study showed that IFN-γ increased HUVECs permeability in a biphasic manner. The hyperpermeability changes may be associated with actin remodeling and alteration of adherens junctions (AJs). In the first phase, IFN-γ caused cell rounding and peripheral actin bands, which may be regulated by caldesmon phosphorylation and dissociation of actin with caldesmon. Besides, IFN-γ induced discontinuous AJs formation without altering the AJs expression level. On the other hand, the second phase of increased permeability involves cell elongation and stress fiber formation, which may be regulated by F-actin hyperpolymerization. Besides, IFN-γ induced linearized AJs, and downregulated the AJs expression level in membrane and cytoskeleton fractions. The results showed that IFN-γ activated p38 MAP kinase in the signaling pathway. However, p38 MAP kinase only regulated the first phase of IFN-γ-mediated increased permeability, and F-actin remodeling. Besides, NO partially regulated the IFN-γ-induced HUVECs hyperpermeability and this was independently of cGMP. In summary, the study enhances the current knowledge on the mechanism of IFN-γ in inducing endothelial dysfunction. The mechanisms underlie IFN-γ-mediated HUVECs hyperpermeability may involve F-actin remodeling and alteration of AJs structure and expression, suggesting that actin cytoskeleton and AJs may serve as the potential therapeutic targets for prevention of the endothelial dysfunction mediated by IFN-γ. The p38 MAP kinase and NO are not the primary regulator for the regulation of IFN-γ-induced endothelial barrier impairment

Dimensionality reduction for predicting student performance in unbalanced data sets

In this study, we evaluated two data sets from two Portuguese schools for predicting student performance. These data sets contain not only the previous grades of the students, but also the demographic, social and school related features. Both data sets are unbalanced in class distribution and contained some irrelevant features. Such characteristics may cause unsatisfactory True Positive (TP) rates for the Fail grade. This grade is important in prediction but it has a low representation as compared with the Pass grade. To improve prediction, dimensionality reduction was performed on both data sets to generate subsets that contained: (i) features selected by a wrapper approach, and (ii) only previous grade(s). The results showed that dimensionality reduction helped to improve the TP rates for the Fail grade. In addition, good classification accuracies were attained. We also noticed that even though the subsets contain only one previous grade, comparable accuracies can also be achieved

A study of the factors affecting consumers' choice of a casual dining western restaurant

100 p.With more people eating out, demand for restaurant food has increased in recent years. In line with this trend, the team decided to conduct a study on factors affecting consumers' choice of a casual dining western restaurant. The factors under study are service, ambience, food, price and other miscellaneous factors.ACCOUNTANC