Phenotyping the Responses to Systemic Corticosteroids in the Management of Asthma Attacks (PRISMA): protocol for an observational and translational pilot study.

INTRODUCTION: Asthma and its associated exacerbation are heterogeneous. Although severe asthma attacks are systematically prescribed corticosteroids and often antibiotics, little is known about the variability of response to these therapies. Blood eosinophils and fractional exhaled nitric oxide (FeNO) are type 2 inflammation biomarkers that have established mechanistic, prognostic and theragnostic values in chronic asthma, but their utility in acute asthma is unclear. We speculate that the clinical and biological response to those treatments varies according to inflammometry and microbiological test results. METHODS AND ANALYSIS: An observational longitudinal pilot study with multimodal clinical and translational assessments will be performed on 50 physician-diagnosed ≥12-year-old asthmatics presenting with an asthma attack and 12 healthy controls, including blood eosinophil count (venous and point-of-care (POC) capillary blood), FeNO and testing for airway infection (sputum cultures and POC nasopharyngeal swabs). People with asthma will be assessed on day 0 and after a 7-day corticosteroid course, with home monitoring performed in between. The primary analysis will be the change in the forced expiratory volume in 1 s according to type 2 inflammatory status (blood eosinophils ≥0.15×109/L and/or FeNO ≥25 ppb) after treatment. Key secondary analyses will compare changes in symptom scores and the proportion of patients achieving a minimal clinically important difference. Exploratory analyses will assess the relationship between clinical, lung function, inflammatory and microbiome parameters; satisfaction plus reliability indices of POC tests; and sex-gender variability in treatment response. Ultimately, this pilot study will serve to plan a larger trial comparing the clinical and biological response to systemic corticosteroids according to inflammatory biomarkers, offering valuable guidance for more personalised therapeutic strategies in asthma attacks. ETHICS AND DISSEMINATION: The protocol has been approved by the Research Ethics Committee of the CIUSSS de l'Estrie-CHUS, Sherbrooke, Quebec, Canada (#2023-4687). Results will be communicated in an international meeting and submitted to a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT05870215).

Healthcare utilization after a first hospitalization for COPD: a new approach of State Sequence Analysis based on the '6W' multidimensional model of care trajectories.

BACKGROUND: Published methods to describe and visualize Care Trajectories (CTs) as patterns of healthcare use are very sparse, often incomplete, and not intuitive for non-experts. Our objectives are to propose a typology of CTs one year after a first hospitalization for Chronic Obstructive Pulmonary Disease (COPD), and describe CT types and compare patients' characteristics for each CT type. METHODS: This is an observational cohort study extracted from Quebec's medico-administrative data of patients aged 40 to 84 years hospitalized for COPD in 2013 (index date). The cohort included patients hospitalized for the first time over a 3-year period before the index date and who survived over the follow-up period. The CTs consisted of sequences of healthcare use (e.g. ED-hospital-home-GP-respiratory therapists, etc.) over a one-year period. The main variable was a CT typology, which was generated by a 'tailored' multidimensional State Sequence Analysis, based on the "6W" model of Care Trajectories. Three dimensions were considered: the care setting ("where"), the reason for consultation ("why"), and the speciality of care providers ("which"). Patients were grouped into specific CT types, which were compared in terms of care use attributes and patients' characteristics using the usual descriptive statistics. RESULTS: The 2581 patients were grouped into five distinct and homogeneous CT types: Type 1 (n = 1351, 52.3%) and Type 2 (n = 748, 29.0%) with low healthcare and moderate healthcare use respectively; Type 3 (n = 216, 8.4%) with high healthcare use, mainly for respiratory reasons, with the highest number of urgent in-hospital days, seen by pulmonologists and respiratory therapists at primary care settings; Type 4 (n = 100, 3.9%) with high healthcare use, mainly cardiovascular, high ED visits, and mostly seen by nurses in community-based primary care; Type 5 (n = 166, 6.4%) with high healthcare use, high ED visits and non-urgent hospitalisations, and with consultations at outpatient clinics and primary care settings, mainly for other reasons than respiratory or cardiovascular. Patients in the 3 highest utilization CT types were older, and had more comorbidities and more severe condition at index hospitalization. CONCLUSIONS: The proposed method allows for a better representation of the sequences of healthcare use in the real world, supporting data-driven decision making.

Greater eosinophil counts at first COPD hospitalization are associated with more readmissions and fewer deaths.

PURPOSE: The impacts of high blood eosinophil count (HBEC) at admission for COPD exacerbation on posthospitalization outcomes are still unclear. Previous studies have focused on its associations with first readmission rates; yet, its impacts on longitudinal outcomes such as subsequent readmissions still have to be explored. The main objective of this study is to investigate outcomes associated with HBEC following a first hospitalization for COPD exacerbation. PATIENTS AND METHODS: This is an observational cohort study design. We retrospectively analyzed data of patients with a first hospitalization within 5 years for COPD exacerbation between April 2006 and March 2013. Patients were stratified into the HBEC group if the blood eosinophil count at admission was ≥200 cells/µL and/or ≥2% of the total white blood cells. With information on exact dates of subsequent hospitalizations and death, we modeled readmissions and death as states in a multi-state Markov model and estimated transition probabilities to the next states. Sensitivity analyses were performed by varying thresholds for the definition of HBEC (≥300 cells/µL and/or ≥3%). RESULTS: A total of 479 patients were included, of which 173 had HBEC. The transition probabilities for a first readmission was 74% (95% CI, 66%-83%) for patients with HBEC vs 70% (95% CI, 63%-77%) for patients with normal blood eosinophil count (NBEC). The transition probabilities for a second readmission were 91% (95% CI, 84%-100%) for HBEC patients in contrast with 83% (95% CI, 74%-92%) for NBEC patients. Meanwhile, transition probability for death was lower in patients with HBEC. The differences enlarged in sensitivity analyses with higher cutoff. CONCLUSION: Greater blood eosinophil cell counts during a first hospitalization for COPD predict increased susceptibility to up to two readmissions. These patients may however have a lower risk of death.

Eosinophil counts in first COPD hospitalizations: a 1-year cost analysis in Quebec, Canada.

BACKGROUND: Exacerbations explain much of the cost of COPD. Higher blood eosinophil cell counts at admission for acute exacerbation of COPD increase the risk of subsequent exacerbations and hospitalizations. However, there is no literature on the economic burden of patients with this inflammatory profile. The objective of this study is to assess the cost of health-care service utilization according to different counts of blood eosinophils. METHODS: The observational retrospective cohort included all first hospitalizations for COPD exacerbation between April 2006 and March 2013. The eosinophilic group was defined by blood eosinophil counts on admission ≥200 cells/µL and/or ≥2% of the total white blood cell count. Study outcomes were: total costs (2016 Canadian dollars) (index hospitalization and 1-year follow-up), total index hospitalization costs, total 1-year costs (all-cause readmissions, ambulatory and emergency service use), and 1-year COPD-related costs (only cost for COPD after initial discharge). Sensitivity analyses were conducted to evaluate the impact of different eosinophil cut-offs on outcomes. RESULTS: In total, 479 patients were included, 173 in the eosinophilic group (92 in the higher cut-off). The average total cost was $18,263 ($6,706 for the index hospitalization), without significant difference between groups (P=0.3). The average 1-year COPD-related cost was higher in the eosinophilic group ($3,667 vs $2,472, P=0.006), with an adjusted mean difference of $1,416. Analysis of data using the higher cut-off of ≥400 cells or ≥3% was associated with a slightly larger difference in 1-year COPD-related costs between groups ($4,060 vs $2,629, P=0.003), with an adjusted mean difference of $1,640. CONCLUSION: A higher blood eosinophil cell count at admission for a first hospitalization is associated with an increase in total 1-year COPD-related costs.

Eosinophil counts in first COPD hospitalizations: a comparison of health service utilization.

PURPOSE: Current evidence suggests that a higher blood eosinophil cell count at admission for acute exacerbation of COPD (AECOPD) is associated with a favorable response to systemic steroids. However, the impact of blood eosinophil counts at admission on post-hospitalization outcomes is still unclear. The main objective of this study is to investigate readmission outcomes associated with blood eosinophilia following severe COPD exacerbation in patients with infrequent COPD hospitalizations. PATIENTS AND METHODS: This is an observational cohort study design. We retrospectively analyzed data of patients with a first hospitalization within 5 years for COPD exacerbation between April 2006 and March 2013. Patients were stratified into the eosinophilic group if the blood eosinophil count on admission was ≥200 cells/µL and/or ≥2% of the total white blood cell (WBC) count. The primary outcome was 1-year COPD-related readmission. Secondary outcomes included 1-year all-cause mortality, 1-year all-cause readmission, length of stay, time to COPD-related readmission, and number of 1-year COPD-associated emergency department (ED) and ambulatory visits. RESULTS: A total of 479 patients were included. Of whom, 173 were stratified into the eosinophilic group. Higher blood eosinophil cell count was associated with an increased risk of 1-year COPD-related readmission (OR, 1.83 [95% CI, 1.16-2.89]; P<0.01), a shorter time to first COPD-related readmission (HR, 1.64 [95% CI, 1.14-2.36]; P<0.01), and an increased number of 1-year COPD-related ED visits (incidence rate ratio, 1.78 [95% CI, 1.21-2.61]; P<0.01). All-cause mortality, all-cause readmission, length of stay, and number of ambulatory visits did not differ between groups. CONCLUSION: Higher blood eosinophil cell count at admission for a COPD exacerbation is associated with increased COPD readmission rates in patients with infrequent COPD hospitalizations.

Predicting One-year Mortality After a "First" Hospitalization for Chronic Obstructive Pulmonary Disease: An Eight-Variable Assessment Score Tool.

Several authors have studied predictors of outcomes following a hospitalization for chronic obstructive pulmonary disease (COPD); however, few have reported outcomes following a first hospitalization for COPD. The objective is to develop a predictive mortality risk model in patients surviving a first hospitalization for COPD. This is a retrospective cohort study using linked administrative and clinical data. The cohort included 1129 patients of 40-84 years, discharged alive from a hospitalization for COPD in a regional hospital (Sherbrooke, Canada) between 04/2006 and 03/2013 and to whom were prescribed at least two COPD drugs during their hospitalization. One-year mortality was analysed using logistic regression on a derivation sample and validated on a testing sample. In total, 141 (12.5%) patients died within one year from discharge of their first hospitalization for COPD. Predictors were: older age (OR (95% CI): 1.055 (1.026-1.085)), male sex (OR (95% CI): 1.474 (0.921-2.358)), having a severe COPD exacerbation (OR (95% CI): 2.548 (1.571-4.132)), higher hospital length of stay (OR (95% CI): 1.024 (0.996-1.053)), higher Charlson co-morbidity index (OR (95% CI): 1.262 (1.099-1.449)), being diagnosed of cancer (OR (95% CI): 2.928 (1.456-5.885)), the number of prior all-cause hospitalizations (OR (95% CI): 1.323 (1.097-1.595)), and a COPD duration exceeding 3 years (OR (95% CI): 1.710 (1.058-2.763)). A simple clinical prognosis tool is proposed and shows good discrimination in both the derivation and validation cohorts (c-statistic >0.78). One over eight patients discharged alive from a first COPD hospitalization will die the following year. It is thus important to identify higher-risk patients in order to plan and manage appropriate treatment.

Characterization of Asthma-Chronic Obstructive Pulmonary Disease Overlap Syndrome: A Qualitative Analysis.

Approximately 15-20% of patients with chronic obstructive pulmonary disease (COPD) also display characteristics of asthma. In May 2014, the asthma-COPD overlap syndrome (ACOS) was briefly addressed in the Global Initiative for Asthma (GINA) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy documents. We evaluated how pulmonologists diagnose and treat ACOS and how they assess its control. Pulmonologists from two university healthcare centers, having ≥ 1 year experience, treating patients with asthma, COPD, or ACOS, were invited to participate in focus groups. Two focus groups (1 hour duration) were convened with seven and five participants, respectively. According to pulmonologists from both institutions, ACOS is a new name for an existing syndrome rather than a new disease. It is characterized by incomplete reversible airflow limitations and changes in forced expiratory volume in one second over time. The pulmonologists noted that its diagnosis must be based on clinical characteristics, pulmonary function test results, and clinical intuition. To diagnose ACOS, pulmonologists must rely on their clinical judgment. They also agreed that the treatment of patients with ACOS should target the features of both asthma and COPD. Pulmonologists from both institutions used asthma control criteria to assess ACOS control. A deeper understanding would enable clinicians to establish specific criteria for the diagnosis, treatment, and follow-up of subjects with ACOS.

Eosinophils in COPD Exacerbations Are Associated With Increased Readmissions.

BACKGROUND: A subset of patients with COPD demonstrates eosinophilic inflammation either in their sputum or blood. Previous studies regarding the association between increased blood eosinophil levels and poor readmission outcomes are conflicting. The goal of this study was to investigate outcomes following severe COPD exacerbations in patients with higher blood eosinophil levels. METHODS: With an observational study design, data on hospitalizations for severe COPD exacerbation were retrospectively gathered. Patient health data previous to and up to 1 year following the index hospitalization were included. Patients were stratified into the eosinophilic group if the blood eosinophil level on admission was ≥ 200 cells/µL and/or ≥ 2% of the total WBC count. Clinical outcomes were 12-month COPD-related readmission, 12-month all-cause readmission, length of stay, and time to COPD-related readmission. These outcomes were analyzed by using logistic, negative binomial, and Cox regression models. RESULTS: A total of 167 patients were included; 55 had eosinophilia. Eosinophilia was associated with an increased risk of 12-month COPD-related readmission (OR, 3.59 [95% CI, 1.65-7.82]; P = .0013), an increased risk of 12-month all-cause readmission (2.32 [95% CI, 1.10-4.92]; P = .0277), and a shorter time to first COPD-related readmission (hazard ratio, 2.74 [1.56-4.83]; P = .0005). The length of stay was not statistically different between eosinophilic and noneosinophilic patients. Sensitivity analyses using different eosinophilia definitions revealed a proportional increase in effect size with increasing eosinophil cell count definitions for predicting 12-month readmissions. CONCLUSIONS: Blood eosinophil levels can be used as a biomarker in severe COPD exacerbations for predicting higher readmission rates.

Adverse events among COPD patients treated with long-acting anticholinergics and ß2-agonists in an outpatient respiratory clinic.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in Canada. Most patients with COPD receive long-term treatment with long-acting anticholinergics (LAAC) and/or long-acting ß2-agonists (LABA). Adverse events (AEs) are also likely during long-term treatment with these medications. OBJECTIVE: To evaluate the prevalence of AEs in COPD patients on LAAC and LABA in a real-world setting. METHODS: We conducted a cross-sectional study of patients enrolled in the Registre de Données en Santé Pulmonaire (RESP) database, which records information on Canadian patients with asthma or COPD. COPD Patients completed a questionnaire about AEs that may be associated with LAAC and/or LABA. The prevalence of AEs and the corresponding 95% CI were calculated for three groups of patients (LAAC + LABA, LAAC alone, and LABA alone). RESULTS: Most patients with COPD (n = 154) were current or ex-smokers. Over 50% of patients were overweight or obese, and had an annual family income of less or equal to $42,000. Dry mouth (55.2%, 40%, and 43.5%) and dry throat (33.6%, 26.7%, and 34.8%) occurred most of the time or always in the LAAC + LABA, LAAC, and LABA groups, respectively. Headache was reported by 17.4% of patients in the LABA group, but less than 11.2% in the other groups. CONCLUSION: AEs reported in this study deserve clinical attention because they may negatively affect quality of life and treatment adherence of COPD patients.

In-Home Pulmonary Telerehabilitation for Patients with Chronic Obstructive Pulmonary Disease: A Pre-experimental Study on Effectiveness, Satisfaction, and Adherence.

BACKGROUND: Pulmonary rehabilitation (PR) has proven effective in improving exercise tolerance and quality of life in patients with chronic obstructive pulmonary disease (COPD). In Canada, however, there are insufficient rehabilitation services. New strategies such as telerehabilitation must be deployed to increase accessibility. This study aims to investigate the effect of telerehabilitation on exercise tolerance and quality of life and to document patient satisfaction and adherence. MATERIALS AND METHODS: Twenty-six patients with moderate to very severe COPD participated in this pre-/postintervention study. They received 15 in-home teletreatment sessions over 8 weeks via videoconference from a service center to their home. Education was provided via self-learning health capsules. Assessments were carried out twice before (T0 and T1; 8 weeks apart) and immediately after the intervention (T2). Primary outcome measures were changes in exercise tolerance (6-min walk test [6MWT] and cycle endurance test [CET]) and quality of life (Chronic Respiratory Questionnaire [CRQ]). RESULTS: There were significant improvements between pre- and postintervention (T2-T1) on the 6MWT (32 m; p<0.001), CET (41 s; p=0.005), and three of four CRQ domains (dyspnea [p<0.001], fatigue [p=0.002], and emotion [p=0.002]). Improvements in the CET and fatigue during the 8-week intervention period were greater than changes over 8 weeks of maturation (T1-T0) (p=0.004 and 0.02, respectively). Participants' satisfaction and adherence rate with telerehabilitation were very high. CONCLUSIONS: Using telehealth technology to deliver in-home PR is a feasible and practical solution for patients with moderate to very severe COPD. The telerehabilitation program was associated with beneficial effects on exercise tolerance and quality of life and was well received by users.

Systemic corticosteroids for the treatment of asthma exacerbations during and outside of pregnancy in an acute-care setting.

BACKGROUND: Asthma exacerbations are common during pregnancy with a prevalence as high as 51.9% among women with severe asthma. OBJECTIVE: To compare the treatment of asthma exacerbations in an acute-care setting during and outside of pregnancy. METHODS: We formed a cohort of women who sought medical care for an asthma exacerbation at a teaching hospital during or in the year preceding pregnancy, between 1998 and 2008. An exacerbation was composed of one or more medical encounters in an acute-care setting (hospital-based outpatient clinic, emergency department, or during hospitalization). Data were retrieved from medical charts and health administrative databases. We compared the use of systemic corticosteroids (SCSs) during and outside of pregnancy with a Cox proportional hazards model. RESULTS: The cohort was formed of 39 women who had 40 exacerbations during and 39 exacerbations outside of pregnancy. Use of SCSs to treat exacerbations was less frequent (adjusted hazard ratio: 0.51; 95% CI: 0.31-0.84) during pregnancy. Moreover, upon the first medical encounter related to the exacerbation, SCSs, when administered, were given less frequently to women when pregnant than when non-pregnant (83% vs. 100%). The SCS prescription was filled at the community pharmacy 65% and 67% of the time when it was prescribed at discharge to women when pregnant than when non-pregnant, respectively. CONCLUSION: We observed a reduced and delayed use of SCSs for the treatment of asthma exacerbations in women when pregnant than when non-pregnant, with similar numbers of women in both conditions filling their SCSs prescription in pharmacies.

Relative perinatal safety of salmeterol vs formoterol and fluticasone vs budesonide use during pregnancy.

BACKGROUND: Recent asthma guidelines endorse the safety of long-acting ß2-agonists (LABAs) and of mild and moderate doses of inhaled corticosteroids (ICSs) when required to control asthma during pregnancy, yet do not state a preferred medication within each class. OBJECTIVE: To estimate the relative perinatal safety with the use of salmeterol and formoterol (LABAs) and that of fluticasone and budesonide (ICSs) during pregnancy. METHODS: A subcohort of pregnancies from asthmatic women was selected from health care administrative databases of Quebec, Canada. Low birth weight (LBW) was defined as weight less than 2,500 g, preterm birth (PB) as delivery before 37 weeks of gestation, and small for gestational age (SGA) as a birth weight below the 10th percentile. The effect of treatment with salmeterol vs formoterol and fluticasone vs budesonide on the outcomes was determined with generalized estimating equation models. RESULTS: The LABA and ICS subcohorts were composed of 547 (385 salmeterol and 162 formoterol users) and 3,798 (3,190 fluticasone and 608 budesonide users) pregnancies, respectively. No statistically significant differences were observed for LBW (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.44-1.88), PB (OR, 1.11; 95% CI, 0.56-2.23), and SGA (OR, 1.16; 95% CI, 0.67-2.02) newborns between women exposed to salmeterol vs formoterol or between women exposed to fluticasone vs budesonide (LBW: OR, 1.08; 95% CI, 0.76-1.52; PB: OR, 1.07; 95% CI, 0.78-1.49; and SGA, OR: 1.10; 95% CI, 0.85-1.44). CONCLUSION: This study does not provide evidence of greater perinatal safety for one LABA or one ICS over the other.

Are improvements maintained after in-home pulmonary telerehabilitation for patients with chronic obstructive pulmonary disease?

This study investigated if improvements can be maintained over 24 weeks when in-home pulmonary telerehabilitation is combined with asynchronous self-management education for Chronic Obstructive Pulmonary Disease (COPD). Twenty-three community-living elders with moderate to very severe COPD participated in a pre/post-intervention study. Over 8 weeks, they had access to self-learning capsules on self-management, received 15 in-home teletreatment sessions and were encouraged to gradually engage in unsupervised sessions. Participants were assessed before the intervention (T1), immediately after the intervention (T2), and 6 months later (T3). Outcome measures were (1) exercise tolerance (6-minute walk test [6MWT]), Cycle Endurance Test [CET]), and (2) quality of life (Chronic Respiratory Questionnaire [CRQ]). Although there were significant improvements after 8 weeks of pulmonary telerehabilitation on the 6MWT, CET and three of four CRQ domains, none of these improvements were maintained after 6 months and scores returned to their baseline values (all p values > 0.05 when comparing T3 with T1). While pulmonary telerehabilitation is possible and has a positive impact on patients with moderate to very severe COPD, improvements were not maintained in the long-term even when physical therapy was accompanied by self-management education.

Impact of maternal use of asthma-controller therapy on perinatal outcomes.

BACKGROUND: Asthma during pregnancy usually requires treatment with controller medications about which more safety information is needed. The objectives are to assess the impact of the use of long-acting ß2-agonists (LABAs) and the dose of inhaled corticosteroids (ICSs) during pregnancy on the prevalence of low birth weight (LBW), preterm birth (PB) and small for gestational age (SGA). METHODS: A cohort of women with asthma giving birth from 1998 to 2008 was constructed from Québec (Canada) administrative databases. LBW was defined as weight <2500 g, PB as delivery before 37 weeks' gestation and SGA as a birth weight below the 10th percentile. The impact of the use of LABAs and the dose of ICSs during pregnancy on the outcomes was determined with generalised-estimating-equation models. RESULTS: The cohort included 7376 pregnancies: 8.8% exposed to LABAs and 56.9% exposed to ICSs. All LABA users also received ICSs. The prevalence of LBW, PB and SGA was 7.7%, 9.5% and 13.5%, respectively. LABA use was not found to be associated with increased prevalence of LBW (OR 0.81; 95% CI 0.58 to 1.12), PB (OR 0.84; 95% CI 0.61 to 1.15) or SGA (OR 0.92; 95% CI 0.70 to 1.20). Mean ICSs doses >125 µg/day (fluticasone-equivalent) were associated with a non-significant trend of increased LBW, PB and SGA. CONCLUSIONS: Despite the possibility of residual confounding due to uncontrolled or more severe asthma or smoking status, the use of LABA and low to moderate doses of ICSs were not associated with increased prevalence of perinatal outcomes. Additional research on higher ICSs doses is required to better evaluate their safety during pregnancy.

Plasma biomarkers and cystic fibrosis lung disease.

PURPOSE: The purpose of this study was to determine whether plasma biomarkers reflect changes in lung function and respiratory exacerbations associated with CF lung disease. METHODS: Plasma human leukocyte elastase/alpha1 antitrypsin complex (pHLE complex) values were measured in 28 adult CF patients and 47 healthy volunteers and correlated with forced expiratory volume (FEV1) and forced vital capacity (FVC). pHLE complexes were studied during respiratory exacerbations and after antibiotic therapy. Plasma cytokines and sialic acid were also measured. RESULTS: pHLE complexes were increased in CF patients (p < 0.01), were inversely correlated with FEV1 (r = 0.71) and FVC (r = 0.67) and returned to normal levels after intravenous antibiotics (p < 0.001). Plasma cytokines did not correlate with lung function. Total sialic acid increased during CF respiratory exacerbations and decreased after antibiotic therapy. CONCLUSION: Plasma sialic acid and pHLE complexes reflect clinically meaningful changes in CF lung disease. In contrast, plasma cytokine levels did not correlate with lung function.

Differential role of NF-κB, ERK1/2 and AP-1 in modulating the immunoregulatory functions of bone marrow-derived dendritic cells from NOD mice.

Tolerogenic dendritic cells represent a promising immunotherapy in autoimmunity. However, the molecular mechanisms that drive tolerogenic DCs functions are not well understood. We used GM-CSF or GM-CSF+IL-4 to generate tolerogenic (GM/DCs) and immunogenic (IL-4/DCs) BMDCs from NOD mice, respectively. GM/DCs were resistant to maturation, produced large amounts of IL-10 but not IL-12p70. GM/DCs displayed a reduced capacity to activate diabetogenic CD8(+) T-cells and were efficient to induce Tregs expansion and conversion. LPS stimulation triggered ERK1/2 activation that was sustained in GM/DCs but not in IL-4/DCs. ERK1/2 and AP-1 were involved in IL-10 production in GM/DCs but not in their resistance to maturation. Supershift analysis showed that NF-κB DNA binding complex contains p52 and p65 in GM/DCs, whereas it contains p52, p65 and RelB in IL-4/DCs. ChIP experiments revealed that p65 was recruited to IL-10 promoter following LPS stimulation of GM/DCs whereas its binding to IL-12p35 promoter was abolished. Our results suggest that immunoregulatory functions of GM/DCs are differentially regulated by ERK1/2, AP-1 and NF-κB pathways.

Benefits of low-dose inhaled fluticasone on airway response and inflammation in mild asthma.

RATIONALE: Current guidelines suggest that asthma should be controlled with the lowest dose of maintenance medication required. OBJECTIVES: To evaluate the effects of a low dose of inhaled corticosteroid compared to a placebo, on airway inflammation and responsiveness in patients with mild symptomatic asthma. METHODS: In this randomized double-blind, placebo-controlled, parallel group study, we looked at the influence of inhaled fluticasone propionate 250 microg/day for 3 months followed by 100 microg/day for 9 months on airway inflammation and methacholine responsiveness in non-smoking subjects with mild allergic asthma. Subjects were evaluated at baseline and 3, 6, 9 and 12 months after treatments; a 2-week evaluation of respiratory symptoms and peak expiratory flow measurements was done before each visit. RESULTS: Fifty-seven subjects completed the 3-month study period. Airway responsiveness, expressed as the PC20 methacholine, increased by 0.27 and 1.14 doubling concentrations, respectively, in placebo-treated (n=33) and in fluticasone-treated (n=24) asthmatic subjects (p=0.03). An additional improvement in PC20 up to 2.16 doubling concentrations was observed in the fluticasone-treated group during the 9-month lower-dose treatment (p=0.0004, end of low-dose period compared with placebo). Sputum eosinophil counts decreased after 3 months of fluticasone 250 microg/day compared with placebo (p<0.0001) and remained in the normal range during the 9-month lower-dose treatment. Respiratory symptoms and peak expiratory flows did not change significantly throughout the study in both groups. CONCLUSION: In mild asthma, keeping a regular minimal dose of ICS after asthma control has been achieved, may lead to a further reduction in airway responsiveness and keep sputum eosinophil count within the normal range.

Inflammatory cytokine production by human neutrophils involves C/EBP transcription factors.

A growing number of neutrophil-derived cytokines have proven to be crucial to various inflammatory and immune processes in vivo. Whereas C/EBP (CCAAT/enhancer-binding protein) transcription factors are important for neutrophil differentiation from myeloid precursors, we report herein that they also regulate cytokine production in mature neutrophils. All known C/EBP proteins but C/EBPgamma are expressed in neutrophils; most isoforms localize to the nucleus, except for C/EBPalpha, which is cytoplasmic. Neutrophil stimulation does not alter the overall levels, cellular distribution, or turnover of C/EBP proteins; it also does not further induce the constitutive DNA-binding activity detected in nuclear extracts, consisting of C/EBPbeta and C/EBPepsilon. However, nuclear C/EBPbeta is rapidly phosphorylated upon cell stimulation, suggesting that it can activate cytokine promoters. Indeed, the transactivation of an IL-8 promoter-luciferase construct in a human neutrophil-like cell line was impaired when its C/EBP or NF-kappaB sites were mutated. Overexpression of a C/EBP repressor also impeded IL-8 promoter transactivation, as well as the generation of IL-8, Mip-1alpha, and Mip-1beta in this cellular model, whereas TNF-alpha generation was mostly unaffected. Finally, overexpression of a C/EBPbeta mutant (T235A) as well as chromatin immunoprecipitation assays unveiled an important role for this residue in cytokine induction. This is the first demonstration that C/EBP factors are important regulators of cytokine expression in human neutrophils.

Signaling by the cysteinyl-leukotriene receptor 2. Involvement in chemokine gene transcription.

Cysteinyl-leukotrienes are involved in inflammation and act on at least two G-protein-coupled receptors, CysLT1 and CysLT2. However, the role of the CysLT2 receptor as well as its signaling remain poorly understood. Here we show that leukotriene (LT)C(4) induced the production of the chemokine interleukin (IL)-8 in endothelial cells. To further study the signaling cascade involved, HEK293 cells were stably transfected with CysLT2 and used to study the transcriptional regulation of the IL-8 promoter. Stimulation of the cells with increasing concentrations of LTC(4) resulted in a time- and concentration-dependent induction of IL-8 transcription and protein synthesis. Use of IL-8 promoter mutants with substitutions in their NF-kappaB, AP-1, or NF-IL-6 binding elements revealed an almost total requirement for NF-kappaB and AP-1 elements, and a lesser requirement for the NF-IL-6 element. Overexpression of dominant-negative IkappaBalpha prevented the IL-8 transactivation induced by LTC(4). LTC(4) stimulation induced NF-kappaB and AP-1 DNA binding, which involved the formation of a p50/p65 and a c-JUN.c-FOS complex, respectively. Transfection of the cells with a dominant negative (dn) form of PKCepsilon prevented p65 phosphorylation, whereas dnPKCdelta prevented AP-1 binding. Moreover, dnPKCdelta, dnPKCepsilon, and dnPKCzeta prevented LTC(4)-induced IL-8 transcription in response to LTC(4). Our data show for the first time that LTC(4) can act via the CysLT2 receptor to transcriptionally activate chemokine production through induction of NF-kappaB and AP-1 transcription factors. These findings suggest the potential implication of CysLT2 in the inflammatory response through the modulation of chemokine gene transcription.

CysLT1 receptor engagement induces activator protein-1- and NF-kappaB-dependent IL-8 expression.

Because cysteinyl-leukotrienes (cysLTs) are major protagonists in the pathophysiology of human asthma, and because neutrophils are involved in the more severe form of asthma, we studied the potential for leukotriene (LT) D(4) to induce synthesis of the chemokine IL-8 through activation of the CysLT1 receptor. We found LTD(4) to induce IL-8 gene expression in monocytic THP-1 cells and human dendritic cells with complete abrogation by selective CysLT1 antagonists. Human embryonic kidney-293 cells stably transfected with CysLT1 were used to better study the transcriptional regulation of the IL-8 promoter. Stimulation of the cells with graded concentrations of LTD(4) resulted in a time- and concentration-dependent induction of IL-8 transcription and protein synthesis. Use of IL-8 promoter mutants with substitutions in their NF-kappaB, activator protein (AP)-1, and NF-IL-6 binding elements revealed a requirement for NF-kappaB and AP-1, but not NF-IL-6, in LTD(4)-induced activation of the IL-8 promoter. Overexpression of dominant-negative IkappaBalpha inhibited the IL-8 transactivation induced by LTD(4). NF-kappaB DNA binding activity was induced by LTD(4), as determined by electrophoretic mobility shift assays, and could be supershifted by antibodies against p50 and p65. Supershift assays after LTD(4) stimulation also indicated the formation of a c-Jun/c-Fos complex. Moreover, our results demonstrate that LTD(4) upregulates the expression of c-fos and c-jun at the mRNA level. Our data show for the first time that LTD(4), via the CysLT1 receptor, can transcriptionally activate IL-8 production, with involvement of the transcription factors p50, p65, Fos, and Jun. These findings provide mechanistic and potentially therapeutic elements for modulation of the inflammatory component of asthma.