The Na+/H+ Exchanger Controls Deoxycholic Acid-Induced Apoptosis by a H+-Activated, Na+-Dependent Ionic Shift in Esophageal Cells

Apoptosis resistance is a hallmark of cancer cells. Typically, bile acids induce apoptosis. However during gastrointestinal (GI) tumorigenesis the cancer cells develop resistance to bile acid-induced cell death. To understand how bile acids induce apoptosis resistance we first need to identify the molecular pathways that initiate apoptosis in response to bile acid exposure. In this study we examined the mechanism of deoxycholic acid (DCA)-induced apoptosis, specifically the role of Na+/H+ exchanger (NHE) and Na+ influx in esophageal cells. In vitro studies revealed that the exposure of esophageal cells (JH-EsoAd1, CP-A) to DCA (0.2 mM -0.5 mM) caused lysosomal membrane perturbation and transient cytoplasmic acidification. Fluorescence microscopy in conjunction with atomic absorption spectrophotometry demonstrated that this effect on lysosomes correlated with influx of Na+, subsequent loss of intracellular K+, an increase of Ca2+ and apoptosis. However, ethylisopropyl-amiloride (EIPA), a selective inhibitor of NHE, prevented Na+, K+ and Ca2+ changes and caspase 3/7 activation induced by DCA. Ouabain and amphotericin B, two drugs that increase intracellular Na+ levels, induced similar changes as DCA (ion imbalance, caspase3/7 activation). On the contrary, DCA-induced cell death was inhibited by medium with low a Na+ concentrations. In the same experiments, we exposed rat ileum ex-vivo to DCA with or without EIPA. Severe tissue damage and caspase-3 activation was observed after DCA treatment, but EIPA almost fully prevented this response. In summary, NHE-mediated Na+ influx is a critical step leading to DCA-induced apoptosis. Cells tolerate acidification but evade DCA-induced apoptosis if NHE is inhibited. Our data suggests that suppression of NHE by endogenous or exogenous inhibitors may lead to apoptosis resistance during GI tumorigenesis

Impact of simulation-based training on perceived provider confidence in acute multidisciplinary pediatric trauma resuscitation.

PURPOSE: Simulation-based training has the potential to improve team-based care. We hypothesized that implementation of an in situ multidisciplinary simulation-based training program would improve provider confidence in team-based management of severely injured pediatric trauma patients. METHODS: An in situ multidisciplinary pediatric trauma simulation-based training program with structured debriefing was implemented at a free-standing childrens hospital. Trauma providers were anonymously surveyed 1 month before (pre-), 1 month after (post-), and 2 years after implementation. RESULTS: Survey response rate was 49% (n = 93/190) pre-simulation, 22% (n = 42/190) post-simulation, and 79% (n = 150/190) at 2-year follow-up. These providers reported more anxiety (p = 0.01) and less confidence (p = 0.02) 1-month post-simulation. At 2-year follow-up, trained providers reported less anxiety (p = 0.02) and greater confidence (p = 0.01), compared to untrained providers. CONCLUSIONS: Implementation of an in situ multidisciplinary pediatric trauma simulation-based training program may initially lead to increased anxiety, but long-term exposure may lead to greater confidence. LEVEL OF EVIDENCE: II, Prospective cohort

Impact of simulation-based training on perceived provider confidence in acute multidisciplinary pediatric trauma resuscitation

Simulation-based training has the potential to improve team-based care. We hypothesized that implementation of an in situ multidisciplinary simulation-based training program would improve provider confidence in team-based management of severely injured pediatric trauma patients.An in situ multidisciplinary pediatric trauma simulation-based training program with structured debriefing was implemented at a free-standing children’s hospital. Trauma providers were anonymously surveyed 1 month before (pre-), 1 month after (post-), and 2 years after implementation.Survey response rate was 49% (n = 93/190) pre-simulation, 22% (n = 42/190) post-simulation, and 79% (n = 150/190) at 2-year follow-up. These providers reported more anxiety (p = 0.01) and less confidence (p = 0.02) 1-month post-simulation. At 2-year follow-up, trained providers reported less anxiety (p = 0.02) and greater confidence (p = 0.01), compared to untrained providers.Implementation of an in situ multidisciplinary pediatric trauma simulation-based training program may initially lead to increased anxiety, but long-term exposure may lead to greater confidence.II, Prospective cohort

Characterization of squamous esophageal cells resistant to bile acids at acidic pH: implication for Barrett's esophagus pathogenesis

Barrett's esophagus (BE) is a premalignant condition, where normal squamous epithelium is replaced by intestinal epithelium. BE is associated with an increased risk of developing esophageal adenocarcinoma (EAC). However, the BE cell of origin is not clear. We hypothesize that BE tissue originates from esophageal squamous cells, which can differentiate to columnar cells as a result of repeated exposure to gastric acid and bile acids, two components of refluxate implicated in BE pathology. To test this hypothesis, we repeatedly exposed squamous esophageal HET1A cells to 0.2 mM bile acid (BA) cocktail at pH 5.5 and developed an HET1AR-resistant cell line. These cells are able to survive and proliferate after repeated 2-h treatments with BA at pH 5.5. HET1AR cells are resistant to acidification and express markers of columnar differentiation, villin, CDX2, and cytokeratin 8/18. HET1AR cells have increased amounts of reactive oxygen species, concomitant with a decreased level and activity of manganese superoxide dismutase compared with parental cells. Furthermore, HET1AR cells express proteins and activate signaling pathways associated with inflammation, cell survival, and tumorigenesis that are thought to contribute to BE and EAC development. These include STAT3, NF-κB, epidermal growth factor receptor (EGFR), cyclooxygenase-2, interleukin-6, phosphorylated mammalian target of rapamycin (p-mTOR), and Mcl-1. The expression of prosurvival and inflammatory proteins and resistance to cell death could be partially modified by inhibition of STAT3 signaling. In summary, our study shows that long-term exposure of squamous cells to BA at acidic pH causes the cells to display the same characteristics and markers as BE

Impact of simulation-based training on perceived provider confidence in acute multidisciplinary pediatric trauma resuscitation

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: Simulation-based training has the potential to improve team-based care. We hypothesized that implementation of an in situ multidisciplinary simulation-based training program would improve provider confidence in team-based management of severely injured pediatric trauma patients. Methods: An in situ multidisciplinary pediatric trauma simulation-based training program with structured debriefing was implemented at a free-standing children’s hospital. Trauma providers were anonymously surveyed 1 month before (pre-), 1 month after (post-), and 2 years after implementation. Results: Survey response rate was 49% (n = 93/190) pre-simulation, 22% (n = 42/190) post-simulation, and 79% (n = 150/190) at 2-year follow-up. These providers reported more anxiety (p = 0.01) and less confidence (p = 0.02) 1-month post-simulation. At 2-year follow-up, trained providers reported less anxiety (p = 0.02) and greater confidence (p = 0.01), compared to untrained providers. Conclusions: Implementation of an in situ multidisciplinary pediatric trauma simulation-based training program may initially lead to increased anxiety, but long-term exposure may lead to greater confidence. Level of evidence: II, Prospective cohort

Impact of simulation-based training on perceived provider confidence in acute multidisciplinary pediatric trauma resuscitation

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: Simulation-based training has the potential to improve team-based care. We hypothesized that implementation of an in situ multidisciplinary simulation-based training program would improve provider confidence in team-based management of severely injured pediatric trauma patients. Methods: An in situ multidisciplinary pediatric trauma simulation-based training program with structured debriefing was implemented at a free-standing children’s hospital. Trauma providers were anonymously surveyed 1 month before (pre-), 1 month after (post-), and 2 years after implementation. Results: Survey response rate was 49% (n = 93/190) pre-simulation, 22% (n = 42/190) post-simulation, and 79% (n = 150/190) at 2-year follow-up. These providers reported more anxiety (p = 0.01) and less confidence (p = 0.02) 1-month post-simulation. At 2-year follow-up, trained providers reported less anxiety (p = 0.02) and greater confidence (p = 0.01), compared to untrained providers. Conclusions: Implementation of an in situ multidisciplinary pediatric trauma simulation-based training program may initially lead to increased anxiety, but long-term exposure may lead to greater confidence. Level of evidence: II, Prospective cohort