Azithromycin Induced Asthma Remission in Adults With Persistent Uncontrolled Asthma: A Secondary Analysis of a Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Asthma remission is a potential treatment goal.

RESEARCH QUESTION

Does adding azithromycin to standard therapy in patients with persistent uncontrolled asthma induce remission compared with placebo?

STUDY DESIGN AND METHODS

This secondary analysis used data from the AMAZES clinical trial-a double-blind placebo-controlled trial that evaluated the safety and efficacy of azithromycin on asthma exacerbations. The primary remission definition (referred to as clinical remission) was zero exacerbations and zero oral corticosteroids during the previous 6 months evaluated at 12 months and a 5-item Asthma Control Questionnaire score ≤ 1 at 12 months. Secondary remission definitions included clinical remission plus lung function criteria (postbronchodilator FEV1 ≥ 80% or postbronchodilator FEV1 ≤ 5% decline from baseline) and complete remission (sputum eosinophil count < 3% plus the aforementioned criteria). Sensitivity analyses explored the robustness of primary and secondary remission definitions. The predictors of clinical remission were identified.

RESULTS

A total of 335 participants (41.5% male; median age, 61.01 years; quartile 1-3, 51.03-68.73) who completed the 12-month treatment period were included in the analysis. Twelve months of treatment with azithromycin induced asthma remission in a subgroup of patients, and a significantly higher proportion in the azithromycin arm achieved both clinical remission (50.6% vs 38.9%; P = .032) and clinical remission plus lung function criteria (50.8% vs 37.1%; P = .029) compared with placebo, respectively. In addition, a higher proportion of the azithromycin group achieved complete remission (23% vs 13.7%; P = .058). Sensitivity analyses supported these findings. Baseline factors (eg, better asthma-related quality of life, absence of oral corticosteroid burst in the previous year) predicted the odds of achieving clinical remission. Azithromycin induced remission in both eosinophilic and noneosinophilic asthma.

INTERPRETATION

Adults with persistent symptomatic asthma achieved a higher remission rate when treated with azithromycin. Remission on treatment may be an achievable treatment target in moderate/severe asthma, and future studies should consider remission as an outcome measure.

Biologics (mepolizumab and omalizumab) induced remission in severe asthma patients

BACKGROUND

Asthma remission has emerged as a potential treatment goal. This study evaluated the effectiveness of two biologics (mepolizumab/omalizumab) in achieving asthma remission.

METHODS

This observational study included 453 severe asthma patients (41% male; mean age ± SD 55.7 ± 14.7 years) from two real-world drug registries: the Australian Mepolizumab Registry and the Australian Xolair Registry. The composite outcome clinical remission was defined as zero exacerbations and zero oral corticosteroids during the previous 6 months assessed at 12 months and 5-item Asthma Control Questionnaire (ACQ-5) ≤1 at 12 months. We also assessed clinical remission plus optimization (post-bronchodilator FEV1 ≥80%) or stabilization (post-bronchodilator FEV1 not greater than 5% decline from baseline) of lung function at 12 months. Sensitivity analyses explored various cut-offs of ACQ-5/FEV1 scores. The predictors of clinical remission were identified.

RESULTS

29.3% (73/249) of AMR and 22.8% (37/162) of AXR cohort met the criteria for clinical remission. When lung function criteria were added, the remission rates were reduced to 25.2% and 19.1%, respectively. Sensitivity analyses identified that the remission rate ranged between 18.1% and 34.9% in the AMR cohort and 10.6% and 27.2% in the AXR cohort. Better lung function, lower body mass index, mild disease and absence of comorbidities such as obesity, depression and osteoporosis predicted the odds of achieving clinical remission.

CONCLUSION

Biologic treatment with mepolizumab or omalizumab for severe asthma-induced asthma remission in a subgroup of patients. Remission on treatment may be an achievable treatment target and future studies should consider remission as an outcome measure.

Sputum TNF markers are increased in neutrophilic and severe asthma and are reduced by azithromycin treatment

BACKGROUND

The AMAZES randomized controlled trial demonstrated that long-term low-dose azithromycin treatment reduces exacerbations of poorly controlled asthma, but the therapeutic mechanisms remain unclear. Dysregulation of the inflammatory tumour necrosis factor (TNF) pathway is implicated in asthma and could be suppressed by azithromycin. We aimed to determine the inflammatory and clinical associations of soluble TNF signalling proteins (TNF receptors [TNFR] 1 and 2, TNF) in sputum and serum, and to test the effect of 48 weeks of azithromycin vs placebo on TNF markers.

METHODS

Sputum supernatant and serum TNFR1, TNFR2 (n = 142; 75 azithromycin-treated, 67 placebo-treated) and TNF (n = 48; 22 azithromycin-treated, 26 placebo-treated) were measured by ELISA in an AMAZES trial sub-population at baseline and end of treatment. Baseline levels were compared between sputum inflammatory phenotypes, severe/non-severe asthma and frequent/non-frequent exacerbators. Effect of azithromycin on markers was tested using linear mixed models.

RESULTS

Baseline sputum TNFR1 and TNFR2 were significantly increased in neutrophilic vs non-neutrophilic asthma phenotypes, while serum markers did not differ. Sputum TNFR1 and TNFR2 were increased in severe asthma and correlated with poorer lung function, worse asthma control and increasing age. Serum TNFR1 was also increased in severe asthma. Sputum and serum TNFR2 were increased in frequent exacerbators. Azithromycin treatment significantly reduced sputum TNFR2 and TNF relative to placebo, specifically in non-eosinophilic participants.

CONCLUSIONS

We demonstrate dysregulation of TNF markers, particularly in the airways, that relates to clinically important phenotypes of asthma including neutrophilic and severe asthma. Suppression of dysregulated TNF signalling by azithromycin could contribute to its therapeutic mechanism.

Airway smooth muscle cells from severe asthma patients with fixed airflow obstruction are responsive to steroid and bronchodilator treatment in vitro

Asthma is characterised by recurrent symptoms associated with variable airflow obstruction and airway hyperresponsiveness, all of which are improved with combination inhaled corticosteroid (ICS)/long-acting β-agonist (LABA) treatment in mild-to-moderate asthma [1]. A proportion of patients however develop fixed airflow obstruction (FAO), despite optimised treatment. FAO is prevalent in up to 60% of patients with severe asthma and is associated with a more rapid decline in lung function and increased symptoms [2]. The underlying mechanisms of FAO in asthma are poorly understood; therefore, development of novel treatment strategies remains a challenge.

Airway smooth muscle cells from severe asthma patients with FAO respond to β₂-agonists and corticosteroids in vitro, and at a level similar to mild asthmatics. Intrinsic dysfunction of these signalling pathways is unlikely to contribute to FAO.https://bit.ly/3muvNsW

A foreign body experience

Foreign body inhalation (FBI) is an uncommon clinical entity in adults. Despite this, FBI is an under-recognized, serious, and easily treatable condition. The authors report a case of a 31-year-old female asthmatic who presented with wheeze and cough not responding to therapy. Chest computed tomography and bronchoscopy confirmed a foreign body distal to the left upper lobe vestibule. The non-organic material was removed with rigid bronchoscopy and cryoprobe with resolution of symptoms. FBI remains an important differential in those presenting with respiratory symptoms in the absence of other diagnoses.

Mepolizumab effectiveness and identification of super-responders in severe asthma

Severe asthma is a high-burden disease. Real-world data on mepolizumab in patients with severe eosinophilic asthma is needed to assess whether the data from randomised controlled trials are applicable in a broader population.The Australian Mepolizumab Registry (AMR) was established with an aim to assess the use, effectiveness and safety of mepolizumab for severe eosinophilic asthma in Australia.Patients (n=309) with severe eosinophilic asthma (median age 60 years, 58% female) commenced mepolizumab. They had poor symptom control (median Asthma Control Questionnaire (ACQ)-5 score of 3.4), frequent exacerbations (median three courses of oral corticosteroids (OCS) in the previous 12 months), and 47% required daily OCS. Median baseline peripheral blood eosinophil level was 590 cells·µL^-1 Comorbidities were common: allergic rhinitis 63%, gastro-oesophageal reflux disease 52%, obesity 46%, nasal polyps 34%.Mepolizumab treatment reduced exacerbations requiring OCS compared with the previous year (annualised rate ratio 0.34 (95% CI 0.29-0.41); p<0.001) and hospitalisations (rate ratio 0.46 (95% CI 0.33-0.63); p<0.001). Treatment improved symptom control (median ACQ-5 reduced by 2.0 at 6 months), quality of life and lung function. Higher blood eosinophil levels (p=0.003) and later age of asthma onset (p=0.028) predicted a better ACQ-5 response to mepolizumab, whilst being male (p=0.031) or having body mass index ≥30 (p=0.043) predicted a lesser response. Super-responders (upper 25% of ACQ-5 responders, n=61, 24%) had a higher T2 disease burden and fewer comorbidities at baseline.Mepolizumab therapy effectively reduces the significant and long-standing disease burden faced by patients with severe eosinophilic asthma in a real-world setting.

Long-Term Azithromycin Reduces Haemophilus influenzae and Increases Antibiotic Resistance in Severe Asthma

Rationale: The macrolide antibiotic azithromycin reduces exacerbations in adults with persistent symptomatic asthma. However, owing to the pleotropic properties of macrolides, unintended bacteriological consequences such as augmented pathogen colonization or dissemination of antibiotic-resistant organisms can occur, calling into question the long-term safety of azithromycin maintenance therapy.Objectives: To assess the effects of azithromycin on the airway microbiota, pathogen abundance, and carriage of antibiotic resistance genes.Methods: 16S rRNA sequencing and quantitative PCR were performed to assess the effect of azithromycin on sputum microbiology from participants of the AMAZES (Asthma and Macrolides: The Azithromycin Efficacy and Safety) trial: a 48-week, double-blind, placebo-controlled trial of thrice-weekly 500 mg oral azithromycin in adults with persistent uncontrolled asthma. Pooled-template shotgun metagenomic sequencing, quantitative PCR, and isolate whole-genome sequencing were performed to assess antibiotic resistance.Measurements and Main Results: Paired sputum samples were available from 61 patients (n = 34 placebo, n = 27 azithromycin). Azithromycin did not affect bacterial load (P = 0.37) but did significantly decrease Faith's phylogenetic diversity (P = 0.026) and Haemophilus influenzae load (P < 0.0001). Azithromycin did not significantly affect levels of Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, or Moraxella catarrhalis. Of the 89 antibiotic resistance genes detected, five macrolide resistance genes and two tetracycline resistance genes were increased significantly.Conclusions: In patients with persistent uncontrolled asthma, azithromycin reduced airway H. influenzae load compared with placebo but did not change total bacterial load. Macrolide resistance increased, reflecting previous studies. These results highlight the need for studies assessing the efficacy of nonantibiotic macrolides as a long-term therapy for patients with persistent uncontrolled asthma.

Outcomes of an initiative to improve inpatient safety of small bore thoracostomy tube insertion

Background

Intercostal chest catheter (ICC) insertion is a common hospital procedure with attendant risks including life‐threatening complications such as pneumothorax and visceral damage.

Aim

To investigate the effect of a quality improvement (QI) initiative on complications associated with inpatient thoracostomy tube insertion.

Methods

Following an audit of ICC complications in inpatients over a 2‐year period we implemented a comprehensive QI programme. This involved formal training in and mandatory use of thoracic ultrasound, standardisation of the procedure and documentation, a dedicated procedure room with nurses trained in assisting ICC insertion and senior supervision for medical staff. An audit over 2 years post‐implementation of the QI protocol was compared with pre‐implementation results.

Results

A total of 103 cases were reviewed pre‐implementation and 105 cases were reviewed post‐implementation of the QI programme. All procedures following the QI initiative were image guided compared to 23.3% of cases pre‐implementation. The rate of developing a pneumothorax requiring intervention post‐implementation was less than pre‐implementation (1.9% vs 5.8% (P = 0.023). Post‐implementation, there were no instances of dry taps, viscera perforation, clinically significant bleeding or wrong side ICC insertion and documentation improved.

Conclusion

QI initiative applied to thoracostomy tube insertion in hospital inpatients can reduce complications and improve procedure documentation.

Efficacy of azithromycin in severe asthma from the AMAZES randomised trial

Background

Low-dose azithromycin is an effective therapy for persistent asthma; however, its benefit in severe asthma is not defined.

Methods

Participants with severe asthma were identified from the AMAZES randomised, placebo-controlled trial of long-term (48 weeks) low-dose azithromycin. Participants who met one of the following severe asthma definitions were included: 1) Global Initiative for Asthma step 4 treatment with poor asthma control (asthma control questionnaire score ≥0.75); 2) International Severe Asthma Registry definition; 3) American Thoracic Society and European Respiratory Society severe asthma definitions. The rate of total exacerbations was calculated for each subgroup and efficacy of azithromycin compared with placebo. Asthma-related quality of life was assessed before and after treatment along with adverse effects.

Results

Azithromycin significantly reduced asthma exacerbations in each group. In patients meeting the American Thoracic Society and European Respiratory Society task force definition of severe asthma (n=211), the rate of exacerbations with treatment was 1.2 per person-year, which was significantly less than for placebo (2.01 per person-year), giving an incidence rate ratio (95% CI) of 0.63 (0.41, 0.96). The proportion of participants experiencing at least one asthma exacerbation was reduced by azithromycin from 64% to 49% (p=0.021). A similar beneficial treatment effect was seen in participants poorly controlled with Global Initiative for Asthma step 4 treatment and those with International Severe Asthma Registry-defined severe asthma. Azithromycin also significantly improved the quality of life in severe asthma (p<0.05). Treatment was well tolerated, with gastrointestinal symptoms being the main adverse effect.

Conclusion

Long-term, low-dose azithromycin reduced asthma exacerbations and improved the quality of life in patients with severe asthma, regardless of how this was defined. These data support the addition of azithromycin as a treatment option for patients with severe asthma.

Low-dose azithromycin is effective therapy for persistent asthma. AMAZES supports AZM as a treatment option for patients with severe asthma. Long-term, low-dose AZM reduces asthma exacerbations and improves quality of life in patients with severe asthma.http://bit.ly/2LWyjYz

Sexual reproduction of Zymoseptoria tritici on durum wheat in Tunisia revealed by presence of airborne inoculum, fruiting bodies and high levels of genetic diversity

Septoria tritici blotch (STB) caused by the heterothallic ascomycete Zymoseptoria tritici is currently one of the most devastating diseases of wheat worldwide. The extent of sexual reproduction of this pathogen is well documented on bread wheat, but not on durum wheat. The objective of the present study was to quantify the occurrence of Z. tritici sexual reproduction on durum wheat in the Tunisian environment. The assessment was undertaken using a triple approach combining fruiting body assessment, ascospore trapping and population genetic analyses. The results highlighted the formation of pseudothecia on leaves and stubble from the autumn until the end of the growing season. Likewise, qPCR monitoring highlighted a constant release of Z. tritici airborne inoculum during the wheat-growing season, with a peak of production at the end of the season. Genetic investigations using microsatellites revealed high levels of gene and genotypic diversities, an equal distribution of mating types, and a lack of genetic clustering within and between growing seasons. Taken together, these findings indicate that Z. tritici undergoes sexual reproduction on durum wheat in Tunisia at least to the same extent than on bread wheat in Western Europe, and that the dry and warm climate does not affect the mating process of the fungus. Frequent occurrence of sexual reproduction is a valuable knowledge to take into account in STB control strategies on durum wheat.

Treatable traits can be identified in a severe asthma registry and predict future exacerbations

BACKGROUND AND OBJECTIVE

A new taxonomic and management approach, termed treatable traits, has been proposed for airway diseases including severe asthma. This study examined whether treatable traits could be identified using registry data and whether particular treatable traits were associated with future exacerbation risk.

METHODS

The Australasian Severe Asthma Web-Based Database (SAWD) enrolled 434 participants with severe asthma and a comparison group of 102 participants with non-severe asthma. Published treatable traits were mapped to registry data fields and their prevalence was described. Participants were characterized at baseline and every 6 months for 24 months.

RESULTS

In SAWD, 24 treatable traits were identified in three domains: pulmonary, extrapulmonary and behavioural/risk factors. Patients with severe asthma expressed more pulmonary and extrapulmonary treatable traits than non-severe asthma. Allergic sensitization, upper-airway disease, airflow limitation, eosinophilic inflammation and frequent exacerbations were common in severe asthma. Ten traits predicted exacerbation risk; among the strongest were being prone to exacerbations, depression, inhaler device polypharmacy, vocal cord dysfunction and obstructive sleep apnoea.

CONCLUSION

Treatable traits can be assessed using a severe asthma registry. In severe asthma, patients express more treatable traits than non-severe asthma. Traits may be associated with future asthma exacerbation risk demonstrating the clinical utility of assessing treatable traits.

Atopic asthmatic immune phenotypes associated with airway microbiota and airway obstruction

Background

Differences in asthma severity may be related to inflammation in the airways. The lower airway microbiota has been associated with clinical features such as airway obstruction, symptom control, and response to corticosteroids.

Objective

To assess the relationship between local airway inflammation, severity of disease, and the lower airway microbiota in atopic asthmatics.

Methods

A cohort of young adult, atopic asthmatics with intermittent or mild/moderate persistent symptoms (n = 13) were assessed via bronchoscopy, lavage, and spirometry. These individuals were compared to age matched non-asthmatic controls (n = 6) and to themselves after six weeks of treatment with fluticasone propionate (FP). Inflammation of the airways was assessed via a cytokine and chemokine panel. Lower airway microbiota composition was determined by metagenomic shotgun sequencing.

Results

Unsupervised clustering of cytokines and chemokines prior to treatment with FP identified two asthmatic phenotypes (AP), termed AP1 and AP2, with distinct bronchoalveolar lavage inflammatory profiles. AP2 was associated with more obstruction, compared to AP1. After treatment with FP reduced MIP-1β and TNF-α and increased IL-2 was observed. A module of highly correlated cytokines that include MIP-1β and TNF-α was identified that negatively correlated with pulmonary function. Independently, IL-2 was positively correlated with pulmonary function. The airway microbiome composition correlated with asthmatic phenotypes. AP2, prior to FP treatment, was enriched with Streptococcus pneumoniae. Unique associations between IL-2 or the cytokine module and the microbiota composition of the airways were observed in asthmatics subjects prior to treatment but not after or in controls.

Conclusion

The underlying inflammation in atopic asthma is related to the composition of microbiota and is associated with severity of airway obstruction. Treatment with inhaled corticosteroids was associated with changes in the airway inflammatory response to microbiota.

Effect of azithromycin on asthma exacerbations and quality of life in adults with persistent uncontrolled asthma (AMAZES): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Exacerbations of asthma cause a substantial global illness burden. Adults with uncontrolled persistent asthma despite maintenance treatment require additional therapy. Since macrolide antibiotics can be used to treat persistent asthma, we aimed to assess the efficacy and safety of oral azithromycin as add-on therapy in patients with uncontrolled persistent asthma on medium-to-high dose inhaled corticosteroids plus a long-acting bronchodilator.

METHODS

We did a randomised, double-blind, placebo controlled parallel group trial to determine whether oral azithromycin decreases the frequency of asthma exacerbations in adults (≥18 years) with symptomatic asthma despite current use of inhaled corticosteroid and long-acting bronchodilator, and who had no hearing impairment or abnormal prolongation of the corrected QT interval. Patients were randomly assigned (1:1) to receive azithromycin 500 mg or placebo three times per week for 48 weeks. Patients were centrally allocated using concealed random allocation from a computer-generated random numbers table with permuted blocks of 4 or 6 and stratification for centre and past smoking. Primary efficacy endpoints were the rate of total (severe and moderate) asthma exacerbations over 48 weeks and asthma quality of life. Data were analysed on an intention-to-treat basis. The trial is registered at the Australian and New Zealand Clinical Trials Registry (ANZCTR), number 12609000197235.

FINDINGS

Between June 12, 2009, and Jan 31, 2015, 420 patients were randomly assigned (213 in the azithromycin group and 207 in the placebo group). Azithromycin reduced asthma exacerbations (1·07 per patient-year [95% CI 0·85-1·29]) compared with placebo (1·86 per patient-year [1·54-2·18]; incidence rate ratio [IRR] 0·59 [95% CI 0·47-0·74]; p<0·0001). The proportion of patients experiencing at least one asthma exacerbation was reduced by azithromycin treatment (127 [61%] patients in the placebo group vs 94 [44%] patients in the azithromycin group, p<0·0001). Azithromycin significantly improved asthma-related quality of life (adjusted mean difference, 0·36 [95% CI 0·21-0·52]; p=0·001). Diarrhoea was more common in azithromycin-treated patients (72 [34%] vs 39 [19%]; p=0·001).

INTERPRETATION

Adults with persistent symptomatic asthma experience fewer asthma exacerbations and improved quality of life when treated with oral azithromycin for 48 weeks. Azithromycin might be a useful add-on therapy in persistent asthma.

FUNDING

National Health and Medical Research Council of Australia, John Hunter Hospital Charitable Trust.

Real-life effectiveness of omalizumab in severe allergic asthma above the recommended dosing range criteria

BACKGROUND

Omalizumab (Xolair) dosing in severe allergic asthma is based on serum IgE and bodyweight. In Australia, patients eligible for omalizumab but exceeding recommended ranges for IgE (30-1500 IU/mL) and bodyweight (30-150 kg) may still receive a ceiling dose of 750 mg/4 weeks. About 62% of patients receiving government-subsidized omalizumab are enrolled in the Australian Xolair Registry (AXR).

OBJECTIVES

To determine whether AXR participants above the recommended dosing ranges benefit from omalizumab and to compare their response to within-range participants.

METHODS

Data were stratified according to dose range status (above-range or within-range). Further sub-analyses were conducted according to the reason for being above the dosing range (IgE only vs. IgE and weight).

RESULTS

Data for 179 participants were analysed. About 55 (31%) were above recommended dosing criteria; other characteristics were similar to within-range participants. Above-range participants had higher baseline IgE [812 (IQR 632, 1747) IU/mL vs. 209 (IQR 134, 306) IU/mL] and received higher doses of omalizumab [750 (IQR 650, 750) mg] compared to within-range participants [450 (IQR, 300, 600) mg]. At 6 months, improvements in Juniper 5-item Asthma Control Questionnaire (ACQ-5, 3.61 down to 2.01 for above-range, 3.47 down to 1.93 for within-range, P < 0.0001 for both) and Asthma Quality of Life Questionnaire (AQLQ mean score (3.22 up to 4.41 for above-range, 3.71 up to 4.88 for within-range, P < 0.0001) were observed in both groups. Forced expiratory volume in one second (FEV₁ ) improved among above-range participants. There was no difference in response between above-range and within-range participants. Above-range participants due to either IgE alone or IgE and weight had similar improvements in ACQ-5, AQLQ and FEV₁ .

CONCLUSIONS AND CLINICAL RELEVANCE

Patients with severe allergic asthma above recommended dosing criteria for omalizumab have significantly improved symptom control, quality of life and lung function to a similar degree to within-range participants, achieved without dose escalation above 750 mg.

Endobronchial deposits of chronic lymphocytic leukemia - an unusual cause of central airway obstruction

A 66-year-old woman with a background of chronic lymphocytic leukemia (CLL) was admitted to the hospital on several occasions with recurrent episodes of community-acquired pneumonia. Computed tomography and bronchoscopy revealed multiple obstructing endobronchial polyps. Post-obstructive pneumonia together with immunoglobulin G deficiency was considered the most likely cause of these recurrent infections. Bronchoscopy was performed for removal of the critically obstructing lesions. Histopathology revealed replacement of bronchial mucosa with CLL deposits. Despite a brief window of infection-free survival following therapy, she remained susceptible to pneumonia with further hospital admissions and eventually died from her disease.

Hypoxia exerts dualistic effects on inflammatory and proliferative responses of healthy and asthmatic primary human bronchial smooth muscle cells

Background

For oxygen supply, airway wall cells depend on diffusion though the basement membrane, as well as on delivery by micro-vessels. In the asthmatic lung, local hypoxic conditions may occur due to increased thickness and altered composition of the basement membrane, as well as due to edema of the inflamed airway wall.

Objective

In our study we investigated the effect of hypoxia on proliferation and pro-inflammatory and pro-angiogenic parameter production by human bronchial smooth muscle cells (BSMC). Furthermore, conditioned media of hypoxia-exposed BSMC was tested for its ability to induce sprout outgrowth from endothelial cells spheroids.

Methods

BSMC were cultured in RPMI1640 (5% FCS) under normoxic (21% O₂) and hypoxic (1% and 5% O₂) conditions. Proliferation was determined by cell count and Western blot analysis for cyclin E and Proliferating Cell Nuclear Antigen (PCNA). Secretion of IL-6, IL-8, ENA-78 and VEGF-A was analyzed by ELISA. BSMC conditioned medium was tested for its angiogenic capacity by endothelial cell (EC)-spheroid in vitro angiogenesis assay.

Results

Proliferation of BSMC obtained from asthmatic and non-asthmatic patients was significantly reduced in the presence of 1% O2, whereas 5% O2 reduced proliferation of asthmatic BSMC only. Hypoxia induced HIF-1α expression in asthmatic and non-asthmatic BSMC, which coincided with significantly increased release of IL-6, IL-8 and VEGF-A, but not ENA-78. Finally, endothelial sprout outgrowth from EC spheroids was increased when exposed to hypoxia conditioned BSMC medium.

Conclusion

Hypoxia had dualistic effects on proliferative and inflammatory responses of asthmatic and non-asthmatic BSMC. First, hypoxia reduced BSMC proliferation. Second, hypoxia induced a pro-inflammatory, pro-angiogenic response. BSMC and EC may thus be promising new targets to counteract and/or alleviate airway wall remodeling.

Is low dose inhaled corticosteroid therapy as effective for inflammation and remodeling in asthma? A randomized, parallel group study

Background

While most of the clinical benefits of inhaled corticosteroid (ICS) therapy may occur at low doses, results of dose-ranging studies are inconsistent. Although symptom/lung function response to low and high dose ICS medication is comparable, it is uncertain whether low dose ICSs are as effective as high dose in the treatment of inflammation and remodeling.

Methods

22 mild or moderate asthmatic adult subjects (corticosteroid free for > 2 months) participated in a randomized, parallel group study to compare effects of fluticasone propionate (FP) 200 mcg/day and 1000 mcg/day. Alveolar macrophage (AM)-derived cytokines and basement membrane thickness (BMT) were measured at baseline and after 7 weeks treatment while symptoms, spirometry, exhaled nitric oxide (eNO) and airway hyperresponsiveness (AHR) to mannitol at baseline and 6 weeks.

Results

FP improved spirometry, eNO, symptoms and AHR with no difference between low and high dose FP. Both high and low dose FP reduced GM-CSF, TNF-alpha and IL-1ra, with no change in BMT and with no differences between low and high dose FP.

Conclusions

200 μg/day of FP was as effective as 1000 μg/day in improving asthma control, airway inflammation, lung function and AHR in adults in the short term. Future studies should examine potential differential effects between low and high dose combination therapy (ICS/long acting beta agonist) on inflammation and airway remodeling over longer treatment periods.

Fibulin-1 is increased in asthma--a novel mediator of airway remodeling?

Background

The extracellular matrix is a dynamic and complex network of macromolecules responsible for maintaining and influencing cellular functions of the airway. The role of fibronectin, an extracellular matrix protein, is well documented in asthma. However, the expression and function of fibulin-1, a secreted glycoprotein which interacts with fibronectin, has not been reported. Fibulin-1 is widely expressed in basement membranes in many organs including the lung. There are four isoforms in humans (A–D) of which fibulin-1C and 1D predominate. The objective of this study was to study the expression of fibulin-1 in volunteers with and without asthma, and to examine its function in vitro.

Methodology/Principal Findings

We used immunohistochemistry and dot-blots to examine fibulin-1 levels in bronchial biopsies, bronchoalveolar lavage fluid and serum. Real-time PCR for fibulin-1C and 1D, and ELISA and western blotting for fibulin-1 were used to study the levels in airway smooth muscle cells. The function of fibulin-1C was determined by assessing its role, using an antisense oligonucleotide, in cell proliferation, migration and wound healing. A murine model of airway hyperresponsiveness (AHR) was used to explore the biological significance of fibulin-1. Levels of fibulin-1 were significantly increased in the serum and bronchoalveolar lavage fluid of 21 asthmatics compared with 11 healthy volunteers. In addition fibulin-1 was increased in asthma derived airway smooth muscle cells and fibulin-1C contributed to the enhanced proliferation and wound repair in these cells. These features were reversed when fibulin-1C was suppressed using an antisense oligomer. In a mouse model of AHR, treatment with an AO inhibited the development of AHR to methacholine.

Conclusions

Our data collectively suggest fibulin-1C may be worthy of further investigation as a target for airway remodeling in asthma.

Reduction of tumstatin in asthmatic airways contributes to angiogenesis, inflammation, and hyperresponsiveness

RATIONALE

Angiogenesis is a prominent feature of remodeling in asthma. Many proangiogenic factors are up-regulated in asthma, but little is known about levels of endogenous antiangiogenic agents. Collagen IV is decreased in the airway basement membrane in asthma. It has six alpha chains, of which the noncollagenous domain-1 domains have endogenous antiangiogenic properties.

OBJECTIVES

To study the expression of the noncollagenous domain-1 of the alpha3 chain of collagen IV, tumstatin, in the airways of subjects with and without asthma and to examine the potential for tumstatin to regulate angiogenesis and inflammation.

METHODS

We used immunohistochemistry and dot blots to examine the expression of tumstatin in bronchial biopsies, bronchoalveolar lavage fluid, and serum. We then used an in vitro angiogenesis assay and a murine model of allergic airways disease to explore tumstatin's biological function.

MEASUREMENTS AND MAIN RESULTS

The level of tumstatin is decreased 18-fold in the airways of patients with asthma but not in subjects without asthma, including those with chronic obstructive pulmonary disease, cystic fibrosis, and bronchiectasis. In vitro, recombinant tumstatin inhibited primary pulmonary endothelial cell tube formation. In a mouse model of chronic allergic airways disease, tumstatin suppressed angiogenesis, airway hyperresponsiveness, inflammatory cell infiltration, and mucus secretion and decreased levels of vascular endothelial growth factor and IL-13.

CONCLUSIONS

The observation that tumstatin is decreased in asthmatic airways and inhibits airway hyperresponsiveness and angiogenesis demonstrates the potential use of antiangiogenic agents such as tumstatin as a therapeutic intervention in diseases that are characterized by aberrant angiogenesis and tissue remodeling, such as asthma.

Decreased hyaluronan in airway smooth muscle cells from patients with asthma and COPD

Glycosaminoglycans (GAG) are essential extracellular matrix molecules which regulate tissue flexibility, a parameter that is reduced in airways of patients with asthma and chronic obstructive pulmonary disease (COPD). We investigated the expression of GAG and their metabolising enzymes in primary human airway smooth muscle cells (ASMC) obtained from healthy donors (controls) and patients with asthma or COPD. Total GAG synthesis was assessed by [(3)H]-glucosamine incorporation. GAG were isolated, purified, fractionated by electrophoresis and characterised using specific GAG-degrading enzymes. Secretion of hyaluronic acid (HA) by ASMC from patients with asthma or COPD was significantly decreased compared with controls. RT-PCR analysis and western blotting revealed that this decrease was associated with a significant reduction in the expression of HA synthase-1 and -2 and a significant increase of hyaluronidase-1. Furthermore, the expression of the HA receptor CD44 was significantly decreased, whereas the receptor for HA-mediated motility was not expressed in asthma or COPD. Our results indicate that there is a decreased expression of HA in asthma and COPD associated with a synergistic regulation of HA metabolising enzymes that may regulate the pathological airway remodelling in these lung diseases.

Impaired translation of CCAAT/enhancer binding protein alpha mRNA in bronchial smooth muscle cells of asthmatic patients

BACKGROUND

Bronchial smooth muscle (BSM) cells of asthmatic patients have an impaired expression of CCAAT/enhancer binding protein (C/EBP) alpha, which is associated with increased proliferation.

OBJECTIVE

We sought to assess the translational regulation of CEBPA mRNA in cultured BSM cells of healthy control subjects (n = 11) and asthmatic patients (n = 12).

METHODS

Translation efficiency was studied by using a translation control reporter system driven by the control elements present in the CEBPA mRNA. Translation efficiency was determined by the ratio of 2 artificial hemagglutinin (HA.11) proteins: p23 and p12. We also analyzed levels of proteins that control translation of CEBPA mRNA, namely heterogeneous nuclear ribonucleoprotein E2, calreticulin, eukaryotic translation initiation factor (eIF4E), and 4E binding protein.

RESULTS

Compared with healthy control subjects, BSM cells of asthmatic patients proliferate faster (2.1-fold) and are primed for IL-6 secretion. Real-time RT-PCR showed that BSM cells of asthmatic patients express normal levels of CEBPA mRNA, whereas they express lower levels of C/EBPalpha (p42). Transient transfections with the translation control reporter system construct showed a disturbed p12/p23 ratio in BSM cells of asthmatic patients relative to healthy control subjects, which coincided with lower levels of eIF4E.

CONCLUSION

BSM cells of asthmatic patients have normal levels of CEBPA mRNA but inadequately reinitiate the translation into C/EBPalpha. Impaired translation control upstream of eIF4E might underlie the observed increased proliferation and priming of BSM cells of asthmatic patients.

Increased proinflammatory responses from asthmatic human airway smooth muscle cells in response to rhinovirus infection

Background

Exacerbations of asthma are associated with viral respiratory tract infections, of which rhinoviruses (RV) are the predominant virus type. Airway smooth muscle is important in asthma pathogenesis, however little is known about the potential interaction of RV and human airway smooth muscle cells (HASM). We hypothesised that rhinovirus induction of inflammatory cytokine release from airway smooth muscle is augmented and differentially regulated in asthmatic compared to normal HASM cells.

Methods

HASM cells, isolated from either asthmatic or non-asthmatic subjects, were infected with rhinovirus. Cytokine production was assayed by ELISA, ICAM-1 cell surface expression was assessed by FACS, and the transcription regulation of IL-6 was measured by luciferase activity.

Results

RV-induced IL-6 release was significantly greater in HASM cells derived from asthmatic subjects compared to non-asthmatic subjects. This response was RV specific, as 5% serum- induced IL-6 release was not different in the two cell types. Whilst serum stimulated IL-8 production in cells from both subject groups, RV induced IL-8 production in only asthmatic derived HASM cells. The transcriptional induction of IL-6 was differentially regulated via C/EBP in the asthmatic and NF-κB + AP-1 in the non-asthmatic HASM cells.

Conclusion

This study demonstrates augmentation and differential transcriptional regulation of RV specific innate immune response in HASM cells derived from asthmatic and non-asthmatics, and may give valuable insight into the mechanisms of RV-induced asthma exacerbations.

Mast cell migration to Th2 stimulated airway smooth muscle from asthmatics

BACKGROUND

Mast cell microlocalisation within the airway smooth muscle (ASM) bundle is an important determinant of the asthmatic phenotype. We hypothesised that mast cells migrate towards ASM in response to ASM derived chemokines.

METHODS

Primary ASM cultures from subjects with and without asthma were stimulated with interleukin (IL)-1beta, IL-4, and IL-13 alone and in combination. Mast cell chemotaxis towards these ASM supernatants was investigated, and the chemotaxins mediating migration by using specific blocking antibodies for stem cell factor (SCF) and the chemokine receptors CCR3, CXCR1, 3 and 4 as well as the Gi inhibitor pertussis toxin and the tyrosine kinase inhibitor genistein were defined. The concentrations of CCL11, CXCL8, CXCL10, TGF-beta, and SCF in the supernatants were measured and the effect of non-asthmatic ASM supernatants on the mast cell chemotactic activity of asthmatic ASM was examined.

RESULTS

Human lung mast cells and HMC-1 cells migrated towards Th2 stimulated ASM from asthmatics but not non-asthmatics. Mast cell migration was mediated through the combined activation of CCR3 and CXCR1. CCL11 and CXCL8 expression by ASM increased markedly after stimulation, but was similar in those with and without asthma. ASM supernatants from non-asthmatics inhibited mast cell migration towards the asthmatic ASM supernatant.

CONCLUSION

Th2 stimulated ASM from asthmatics is chemotactic for mast cells. Non-asthmatic ASM releases a mediator or mediators that inhibit mast cell migration towards stimulated asthmatic ASM. Specifically targeting mast cell migration into the ASM bundle may provide a novel treatment for asthma.

[Recessive osteopetrosis. Identification of a form of medium severity]

BACKGROUND

Several distinct forms of osteopetrosis have been identified. Some of the autosomally recessive inherited forms are benign, much like the autosomal dominant form. Others are more malignant.

PATIENTS

The clinical data, skeletal radiographs, histological features and histories of 32 children with osteopetrosis were analyzed retrospectively.

RESULTS

The 32 patients, belonging to 20 sibships were divided into two groups. The first group included 24 patients, aged 1 day-11 months (mean 4.5 months), suffering from hepatosplenomegaly, anemia, thrombocytopenia and optic atrophy in early infancy. They also had a generalized increase in bone density, abnormal bone remodeling, rachitic lesions and a "bone-within-bone" appearance. Biopsies showed severe bone resorption and myelofibrosis. 19 of the 20 patients whose outcomes were known died during the first year of life. The second group included 8 patients, aged 40 days-3 years (mean: 11 months). Hepatosplenomegaly appeared later, anemia was less severe and thrombocytopenia occurred in only 1 patient. However, all 8 patients suffered from optic atrophy and 3 were deaf. Radiographs showed bone growth without rachitic lesions. Biopsies from 2 patients showed bone resorption, but no myelofibrosis. The outcome was less severe: 6 patients, now aged 8 months to 8 years, have survived, 3 of them for over 5 years. Genetic investigation showed patterns compatible with autosomal recessive inheritance in both groups, with similar sets of features within each sibship.

CONCLUSION

This study reveals a new type of recessively inherited osteopetrosis. It can be classified as an intermediate form, distinct from both the malignant and the benign forms, and also distinct from osteopetrosis with carbonic anhydrase II deficiency.

[Early severe spinal lesions in Bourneville's tuberous sclerosis]

An exceptional case of tuberous sclerosis with marked extensive lesion of the spine in the first year of life is reported. This lesion required orthopedic treatment at the age of 3 years and surgery at the age of 6 years.

[Syndrome associating: osteopetrosis, tubular acidosis, mental retardation and cerebral calcifications due to carbonic anhydrase II deficiency. Apropos of 3 cases in the siblings]

Three new cases of a syndrome including osteopetrosis, tubular acidosis, mental retardation and cerebral calcifications are reported in the same sibship. This rare syndrome has an autosomal recessive inheritance and is due to carbonic anhydrase II deficiency. Fractures and mild sensorial manifestations were noticed in 2 cases. Mental deficiency and otitis were present in the 3 cases. Blood count and phosphocalcic metabolites were normal. A proximal tubular acidosis was present in each case. The radiological features were specific: cerebral calcifications were present in all cases since the age of 2 1/2 years; osteocondensation and bone modeling were predominant in long bones metaphyses. Alcalinization improved the height growth.