Diahn-Warng Perng

Mold Allergen, Pen c 13, Induces IL-8 Expression in Human Airway Epithelial Cells by Activating Protease-Activated Receptor 1 and 2

Allergenic serine proteases are important in the pathogenesis of asthma. One of these, Pen c 13, is the immunodominant allergen produced by Penicillium citrinum. Many serine proteases induce cytokine expression, but whether Pen c 13 does so in human respiratory epithelial cells is not known. In this study, we investigated whether Pen c 13 caused IL-8 release and activated protease-activated receptors (PARs) in airway epithelial cells. In airway-derived A549 cells and normal human airway epithelial cells, Pen c 13 induced IL-8 release in a dose-dependent manner. Pen c 13 also increased IL-8 release in a time-dependent manner in A549 cells. Pen c 13 cleaved PAR-1 and PAR-2 at their activation sites. Treatment with Pen c 13 induced intracellular Ca2+ mobilization and desensitized the cells to the action of other proteases and PAR-1 and PAR-2 agonists. Moreover, Pen c 13-mediated IL-8 release was significantly decreased in Ca2+-free medium and was abolished by the protease inhibitors, PMSF and 4-(2-aminoethyl) benzenesulfonyl fluoride. Blocking Abs against the cleavage sites of PAR-1 and PAR-2, but not of PAR-4, inhibited Pen c 13-induced IL-8 production, as did inhibition of phospholipase C. Pen c 13 induced IL-8 expression via activation of ERK 1/2, and not of p38 and JNK. In addition, treatment of A549 cells or normal human airway epithelial cells with Pen c 13 increased phosphorylation of ERK 1/2 by a Ca2+-dependent pathway. These finding show that Pen c 13 induces IL-8 release in airway epithelial cells and that this is dependent on PAR-1 and PAR-2 activation and intracellular calcium.

Spontaneous breathing trial needs to be prolonged in critically ill and older patients requiring mechanical ventilation

PURPOSE To investigate a modified weaning procedure to predict extubation outcome in critically older and ventilated patients. METHODS We retrospectively analyzed extubation outcome in older (≥ 70 years) and ventilated patients. In period I (2007), patients passing a 2-hour spontaneous breathing trial (SBT) were extubated. In period II (2008), patients underwent an 8-hour SBT on day 1 and a 2-hour SBT, followed by extubation on day 2. Weaning parameters were recorded at baseline (T(0)) (periods I and II), 2 and 8 (T(8)) hours after SBT (period II). RESULTS The demographic data of patients in each period (n = 64 and 67, respectively) were similar. Patients in period II demonstrated a higher rate of SBT failure but a significantly lower rate of extubation failure and reintubation mortality. In period II, successfully extubated patients demonstrated a significantly lower value of rapid shallow breathing index (RSBI) at T(8). The ratio of RSBI at T(8) over T(0) (T(8)/T(0) ≤ 1.4) demonstrated good diagnostic value (sensitivity 89.5%, specificity 80.0%, accuracy 88.4%) in predicting successful extubation. CONCLUSIONS For critically older and ventilated patients, a prolonged SBT in conjunction with evolution of the RSBI ratio over baseline during SBT may serve as a useful procedure to predict extubation outcome.

Sleep apnea and risk of pneumonia: a nationwide population-based study

Background: Evidence evaluating the risk of pneumonia in patients with obstructive sleep apnea is limited and mostly focuses on patients who receive continuous positive airway pressure (CPAP) therapy or on pediatric patients. We aimed to explore the risk of incident pneumonia among adults with sleep apnea, either with or without the need of CPAP therapy. Methods: From Jan. 1, 2000, we identified adult patients with sleep apnea from the Taiwan National Health Insurance Research Database. A control cohort without sleep apnea, matched for age, sex and comorbidities, was selected for comparison. The 2 cohorts were followed until Dec. 31, 2010, and observed for occurrence of pneumonia. Results: Of the 34 100 patients (6816 study patients and 27 284 matched controls), 2757 (8.09%) had pneumonia during a mean follow-up period of 4.50 years, including 638 (9.36%) study patients and 2119 (7.77%) controls. Kaplan–Meier analysis showed a higher incidence of pneumonia among patients with sleep apnea (log rank test, p < 0.001). After multivariate adjustment, patients with sleep apnea experienced a 1.20-fold (95% confidence interval 1.10–1.31) increase in incident pneumonia. The risk was even higher among patients who received CPAP therapy. Interpretation: Sleep apnea appeared to confer a higher risk for future pneumonia, possibly in a severity-dependent manner.

The Effect of Cold Temperature on Increased Exacerbation of Chronic Obstructive Pulmonary Disease: A Nationwide Study

Background Seasonal variations in the acute exacerbation of chronic obstructive pulmonary disease (COPD) have been reported. However, the influence of air temperature and other meteorological factors on COPD exacerbation remains unclear. Methods National Health Insurance registry data from January 1, 1999 to December 1, 2009 and meteorological variables from the Taiwan Central Weather Bureau for the same period were analyzed. A case-crossover study design was used to investigate the association between COPD exacerbation and meteorological variables. Results A total of 16,254 cases who suffered from COPD exacerbation were enrolled. We found that a 1°C decrease in air temperature was associated with a 0.8% increase in the exacerbation rate on event-days (95% confidence interval (CI), 1.015–1.138, p = 0.015). With a 5°C decrease in mean temperature, the cold temperature (28-day average temperature) had a long-term effect on the exacerbation of COPD (odds ratio (OR), 1.106, 95% CI 1.063–1.152, p<0.001). In addition, elderly patients and those who did not receive inhaled medication tended to suffer an exacerbation when the mean temperature dropped 5°C. Higher barometric pressure, more hours of sunshine, and lower humidity were associated with an increase in COPD exacerbation. Conclusions This study demonstrated the effect of cold temperatures on the COPD exacerbation rate. Elderly patients and those without inhaled medicine before the exacerbation event were affected significantly by lower mean temperatures. A more comprehensive program to prevent cold stress in COPD patients may lead to a reduction in the exacerbations rate of COPD.

Additive benefits of tiotropium in COPD patients treated with long-acting β2 agonists and corticosteroids

Objective and background:  The addition of an alternative class of long‐acting bronchodilator is recommended for COPD patients who do not respond satisfactorily to monotherapy. The aim of this study was to investigate the additive benefit of tiotropium in severe COPD and to establish whether the improvement in lung function in these patients can be predicted from their acute bronchodilator response to ipratropium or salbutamol.

Bile Acid Aspiration in Suspected Ventilator-Associated Pneumonia

AIMS The aims of this study were to measure the levels of bile acids in patients with suspected ventilator-associated pneumonia (VAP) and provide a possible pathway for neutrophilic inflammation to explain its proinflammatory effect on the airway. METHODS Bile acid levels were measured by spectrophotometric enzymatic assay, and liquid chromatography mass spectrometry was used to quantify the major bile acids. Alveolar cells were grown on modified air-liquid interface culture inserts, and bile acids were then employed to stimulate the cells. Reverse transcriptase polymerase chain reaction and Western blots were used to determine the involved gene expression and protein levels. RESULTS The mean (+/- SE) concentration of total bile acids in tracheal aspirates was 6.2 +/- 2.1 and 1.1 +/- 0.4 mumol/L/g sputum, respectively, for patients with and without VAP (p < 0.05). The interleukin (IL)-8 level was significantly higher in the VAP group (p < 0.05). The major bile acid, chenodeoxycholic acid, stimulated alveolar epithelial cells to increase IL-8 production at both the messenger RNA and protein level through p38 and c-Jun N-terminal kinase (JNK) activation. The selective p38 and JNK inhibitors, as well as dexamethasone, successfully inhibited IL-8 production. CONCLUSION These data suggest that early intervention to prevent bile acid aspiration may reduce the intensity of neutrophilic inflammation in intubated and mechanically ventilated patients in the ICU.

Matrix metalloprotease-9 induces transforming growth factor-β1 production in airway epithelium via activation of epidermal growth factor receptors

AIMS Matrix metalloprotease (MMP)-9 is present in abundance in various chronic airway disorders and is involved in lung remodeling. MMP may cleave membrane-bound precursor proteins and release epidermal growth factor-like ligands that subsequently bind to epidermal growth factor receptor (EGFR). We hypothesized that MMP-9 may stimulate the airway epithelium to produce fibrogenic mediators through activation of membrane-bound receptors. MAIN METHODS Human airway epithelial cells were grown on air-liquid interface culture inserts. MMP-9 was employed to stimulate the cells. Conditioned medium following MMP-9 stimulation was co-incubated with human lung fibroblasts. KEY FINDINGS MMP-9 stimulated human airway epithelial cells to produce transforming growth factor (TGF)-β(1) at both the mRNA and protein level. Using a microarray, increased phosphorylation of EGFR tyrosine kinase (TK) was identified and further confirmed by immunoprecipitation and Western blot analysis. A significant increase in EGF and TGF-α release was observed after MMP-9 had been added for 30min. Protease inhibitor, EGFR monoclonal antibody and EGFR-TK inhibitor blocked this action and subsequent TGF-β(1) production. Neutralizing antibodies against EGF and TGF-α substantially inhibited TGF-β(1) production following MMP-9 stimulation. MMP-9-induced TGF-β(1) production occurred through MAP kinase p44/42 phosphorylation. Selective p44/42 kinase inhibitor UO126 successfully inhibited TGF-β(1) production. Conditioned medium from epithelial cells treated with MMP-9 significantly induced Smad3 phosphorylation and subsequent fibroblast proliferation after 24h culture. SIGNIFICANCE These data indicate that MMP-9 induces TGF-β(1) production in the airway epithelium through the cleavage of EGF and EGF-like ligands and activating EGFR, suggesting potential targets of therapeutic intervention in airway fibrotic disorders.

Sleep Apnea and Risk of Retinal Vein Occlusion: A Nationwide Population-Based Study of Taiwanese

PURPOSE To explore the relationship of sleep apnea and the subsequent development of retinal vein occlusion (RVO). DESIGN A retrospective nonrandomized, matched-control cohort study using the Taiwan National Health Insurance Research Database. METHODS From 1997 through 2007, we identified newly diagnosed sleep apnea cases in the database. A control group without sleep apnea, matched for age, gender, and comorbidities, was selected for comparison. The 2 cohorts were followed up, and the occurrence of RVO was observed. RESULTS Of the 35 634 sampled patients (5965 sleep apnea patients vs 29 669 controls), 52 (0.15%) experienced RVO during a mean follow-up period of 3.72 years, including 13 (0.22%, all branch RVO) from the sleep apnea cohort and 39 (0.13%, 39 branch RVO and 10 central RVO) from the control group. Kaplan-Meier analysis revealed the tendency of sleep apnea patients toward RVO development (P = .048, log-rank test). Patients with sleep apnea experienced a 1.94-fold increase (95% confidence interval, 1.03 to 3.65; P = .041) in incident RVO, which was independent of age, gender, and comorbidities. CONCLUSIONS Sleep apnea may be an independent risk factor for RVO.

Sleep disorders and increased risk of autoimmune diseases in individuals without sleep apnea.

STUDY OBJECTIVES To explore the association between the non-apnea sleep disorder (NSD) and autoimmune diseases. DESIGN Cohort study. SETTING Nationwide database research. PARTICIPANTS 84,996 adult patients with NSD diagnoses recorded in the Taiwan National Health Insurance Research Database between 2000 and 2003, after excluding those with antecedent autoimmune diseases. A comparison cohort of 84,996 participants was formed by age-, gender-, income-, and urbanization-matched controls. INTERVENTIONS None. MEASUREMENTS AND RESULTS The two cohorts were followed up for occurrence of autoimmune diseases, including rheumatoid arthritis (RA), ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), Sjögrens syndrome (SS), and systemic sclerosis (SSc). A Cox proportional hazards regression model was used for muti-variate adjustment. In patients with NSD, the overall risk for incident autoimmune diseases was significantly higher than in controls (adjusted hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 1.41-1.53). With regard to individual diseases, the risks for SLE, RA, AS and SS among NSD patients were also significantly higher than in controls (HR [95% CI] for SLE, RA, AS, and SS were 1.81 [1.50-2.18], 1.45 [1.36-1.54], 1.53 [1.38-1.70], and 1.51 [1.43-1.60], respectively), whereas the increased risk for SSc did not reach statistical significance (HR: 1.36 [0.82-2.26]). CONCLUSION Patients with non-apnea sleep disorder were associated with a higher risk for developing autoimmune diseases.

Inflammatory role of AMP-activated protein kinase signaling in an experimental model of toxic smoke inhalation injury.

Objective:The molecular mechanisms underlying lung inflammation in toxic smoke inhalation injury are unknown. We investigated the signaling pathway responsible for the induction of interleukin 8 by wood smoke extract in lung epithelial cells and lung inflammation induced by wood smoke exposure in mice. Design:A randomized, controlled study. Setting:A research laboratory. Interventions and Main Results:Exposure of primary human bronchial epithelial cells to wood smoke extract sequentially activated NADPH oxidase and increased intracellular reactive oxygen species level; activated AMP-activated protein kinase, extracellular signal-regulated kinase and Jun N-terminal kinase (two mitogen-activated protein kinases), and nuclear factor-&kgr;B and signal transducer and activator of transcription protein 3 (two transcription factors); and induced interleukin-8. Inhibition of NADPH oxidase activation with apocynin or siRNA targeting p47phox (a subunit of NADPH oxidase) attenuated the increased intracellular reactive oxygen species level, AMP-activated protein kinase activation, and interleukin-8 induction. Removal of intracellular reactive oxygen species by N-acetyl-cysteine reduced the activation of AMP-activated protein kinase, extracellular signal-regulated kinase and Jun N-terminal kinase, and interleukin-8 induction. Prevention of AMP-activated protein kinase activation by Compound C or AMP-activated protein kinase siRNA lessened the activation of Jun N-terminal kinase, extracellular signal-regulated kinase, nuclear factor-&kgr;B, signal transducer and activator of transcription protein 3 and interleukin-8 induction. Inhibition of Jun N-terminal kinase and extracellular signal-regulated kinase activation by inhibitors reduced the activation of nuclear factor-&kgr;B and signal transducer and activator of transcription protein 3 and interleukin-8 induction. Abrogation of nuclear factor-&kgr;B and signal transducer and activator of transcription protein 3 activation by inhibitors attenuated the interleukin-8 induction. Additionally, acute exposure of mice to wood smoke promoted AMP-activated protein kinase phosphorylation and expression of macrophage inflammatory protein 2 (an interleukin-8 homolog) in lung epithelial cells and lungs and lung inflammation, all of which were reduced by Compound C treatment. Conclusions:Interleukin-8 induction by wood smoke extract in lung epithelial cells is mediated by novel NADPH oxidase-dependent, reactive oxygen species-sensitive AMP-activated protein kinase signaling with Jun N-terminal kinase and extracellular signal-regulated kinase as the downstream kinases and nuclear factor-&kgr;B and signal transducer and activator of transcription protein 3 as the downstream transcription factors. This AMP-activated protein kinase signaling is likely important for inducing lung inflammation with toxic smoke exposure in mice.