Small airways dysfunction in asthma: evaluation and management to improve asthma control

Aerodynamic Simulation of Small Airway Resistance: A New Imaging Biomarker for Chronic Obstructive Pulmonary Disease

Purpose

To develop a novel method for calculating small airway resistance using computational fluid dynamics (CFD) based on CT data and evaluate its value to identify COPD.

Patients and Methods

24 subjects who underwent chest CT scans and pulmonary function tests between August 2020 and December 2020 were enrolled retrospectively. Subjects were divided into three groups: normal (10), high-risk (6), and COPD (8). The airway from the trachea down to the sixth generation of bronchioles was reconstructed by a 3D slicer. The small airway resistance (RSA) and RSA as a percentage of total airway resistance (RSA%) were calculated by CFD combined with airway resistance and FEV1 measured by pulmonary function test. A correlation analysis was conducted between RSA and pulmonary function parameters, including FEV1/FVC, FEV1% predicted, MEF50% predicted, MEF75% predicted and MMEF75/25% predicted.

Results

The RSA and RSA% were significantly different among the three groups (p<0.05) and related to FEV1/FVC (r = -0.70, p < 0.001; r = -0.67, p < 0.001), FEV1% predicted (r = -0.60, p = 0.002; r = -0.57, p = 0.004), MEF50% predicted (r = -0.64, p = 0.001; r = -0.64, p = 0.001), MEF75% predicted (r = -0.71, p < 0.001; r = -0.60, p = 0.002) and MMEF 75/25% predicted (r = -0.64, p = 0.001; r = -0.64, p = 0.001).

Conclusion

Airway CFD is a valuable method for estimating the small airway resistance, where the derived RSA will aid in the early diagnosis of COPD.

Fixed-dose combination fluticasone/formoterol for asthma treatment in a real-world setting: meta-analysis of exacerbation rates and asthma control

BACKGROUND

Treatment guidelines for asthma management are derived almost exclusively from the results of controlled clinical trials undertaken in carefully selected patient populations; meaning that their outcomes may not reflect the true performance of treatments when used in general daily medical practice. The aim of this meta-analysis was to combine the results of observational studies investigating the fluticasone propionate/formoterol (FP/FORM) fixed-dose combination in real-world asthma patients.

METHODS

A systemic literature review was completed in March 2019 using the PubMed database. We identified 394 studies. Five studies, which included a total of 4756 patients treated with FP/FORM, were judged eligible and included in the meta-analysis.

RESULTS

The estimated severe asthma exacerbation rate was 11.47% (95% CI, 5.8 to 18.72%), calculated from the random effect model. A sensitivity analysis excluding 2 studies (one was an outlier, and the exacerbation rate for the studied treatment alone could not be determined in the other) showed a 7.04% rate of severe asthma exacerbations. The estimated relative risk of the incidence of severe asthma exacerbations was 0.323 (95% CI, 0.159 to 0.658). The estimated asthma control rate was 60.6% (95% CI, 55.7% to 65.6%). The odds of achieving asthma control significantly increased by FP/FORM compared with pre-study conditions (estimated odds ratio: 2.214 [95% CI, 1.292 to 3.795]; p < 0.001).

CONCLUSIONS

The findings of this meta-analysis confirm the effectiveness of FP/FORM for the treatment of asthma patients in a real-world setting beyond the limitations of RCTs.

[Quantitative Evaluation of Airway Lesions in Chronic Obstructive Pulmonary Disease by Applying Deep Learning Reconstruction to Ultra-high-resolution CT Images: Correlation between Wall Area Percentage and Forced Expiratory Volume in One Second Percentage]

PURPOSE

Using ultra-high-resolution images reconstructed with the Advanced intelligent Clear-IQ Engine (AiCE) lung to measure wall area percentage (WA%), we demonstrated that WA% measured in more distal bronchus has a stronger correlation with respiratory function (FEV₁%). Furthermore, we also demonstrated that WA% measured from images with the higher spatial resolution has a stronger correlation with FEV₁%.

METHODS

The modulation transfer function (MTF) and noise power spectrum (NPS) of the ultra-high-resolution images reconstructed by the AiCE body and the AiCE lung were compared. In addition, WA% from the first- to seventh-generation bronchus was measured for B1 and B10 in the right lung from clinical images obtained with the two reconstruction methods, and the correlation coefficients with FEV₁% were evaluated.

RESULTS

The MTF was more superior for the AiCE lung than for the AiCE body, and the NPS was lower for the AiCE lung than for the AiCE body in the low-frequency region. The correlation between WA% and FEV₁% was slightly stronger in the AiCE lung than in the AiCE body.

CONCLUSION

This study showed that WA% measured from the 7th-generation bronchus using ultra-high-resolution images reconstructed with the AiCE lung strengthens the correlation with FEV₁%. Furthermore, the higher the spatial resolution of the measurement images, the stronger the correlation between WA% and FEV₁%.

Peripheral airways involvement in children with asthma exacerbation

Objective

The literature provides some evidence of peripheral airways key role in the pathogenesis of asthma. However, the extent to which lung periphery including acinar zone contribute to asthma activity and control in pediatric population is unclear. Therefore, the aim of the study was to estimate peripheral airways involvement in children with asthma exacerbation and stable asthma simultaneously via different pulmonary function tests.

Methods

Children with asthma exacerbation (n = 20) and stable asthma (n = 22) performed spirometry, body plethysmography, exhaled nitric oxide, impulse oscillometry (IOS), and multiple‐breath washout (MBW).

Results

Peripheral airway's function indexes were increased in children with asthma, particularly in group with asthma exacerbation when compared with stable asthma group. The prevalence of abnormal results was significantly higher in asthma exacerbation. All children with asthma exacerbation had conductive ventilation inhomogeneity; 76% had acinar ventilation inhomogeneity. According to IOS measurements, resistance and reactance were within normal range, but other IOS parameters were significantly higher in children with asthma exacerbation compared with stable asthma group. The 36% of children with acute asthma had air trapping.

Conclusion

Significant involvement of peripheral airways was observed in children with asthma, particularly in asthma exacerbation, which determine lung periphery as important additional target for therapy and provide new insights into pathophysiological process of pediatric asthma.

Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

Small airway disease is recognized as a cardinal pathological process of chronic obstructive pulmonary disease (COPD), and recently small airways have been recognized as a major site of airflow obstruction also in asthmatic patients. The transversal involvement of small airways in COPD and asthma has warranted research efforts to identify therapeutic strategies able to unlock the small airway compartment. The mainstay of COPD treatment is represented by long-acting β₂-adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs). In asthma, the efficacy of LAMAs administered add-on to inhaled corticosteroids (ICSs) or ICS/LABA combinations has been investigated only in recent years. The aim of this systematic review was to examine the current literature concerning the impact of LAMAs on small airways and their lung deposition in both COPD and asthma. LAMAs administered either alone or in combination induced an effective bronchorelaxant effect of small airways, however the effectiveness of respiratory medications not only relies on the selected drug, but also on the employed inhalation device and patient's adherence. Tiotropium delivered via Respimat® SMI achieved a superior drug deposition in the peripheral lung compared to HandiHaler® dry powder inhaler and metered-dose inhalers (MDIs). The use of co-suspension™ delivery technology for MDIs and the introduction of the eFlow® nebulizer to deliver glycopyrronium improved aerosol drug delivery to the peripheral lung, by achieving uniform distribution of drug particles. This systematic review provides a synthesis of current literature concerning the impact of LAMAs on small airways and an insight on LAMAs distribution within the lung.

Why We Should Target Small Airways Disease in Our Management of Chronic Obstructive Pulmonary Disease

For more than 50 years, small airways disease has been considered a key feature of chronic obstructive pulmonary disease (COPD) and a major cause of airway obstruction. Both preventable and treatable, small airways disease has important clinical consequences if left unchecked. Small airways disease is associated with poor spirometry results, increased lung hyperinflation, and poor health status, making the small airways an important treatment target in COPD. The early detection of small airways disease remains the key barrier; if detected early, treatments designed to target small airways may help reduce symptoms and allow patients to maintain their activities. Studies are needed to evaluate the possible role of new drugs and novel drug formulations, inhalers, and inhalation devices for treating small airways disease. These developments will help to improve our management of small airways disease in patients with COPD.

The Value of Fractional Exhaled Nitric Oxide and Impulse Oscillometric and Spirometric Parameters for Predicting Bronchial Hyperresponsiveness in Adults with Chronic Cough

Purpose

To evaluate the contribution of fractional exhaled nitric oxide (FeNO) and impulse oscillometry (IOS) and spirometric parameters in predicting bronchial hyperresponsiveness (BHR) in adults with chronic cough.

Patients and Methods

In total, 112 patients with chronic cough were enrolled in this prospective diagnostic study. Receiver operating characteristic (ROC) curves were generated to assess the diagnostic efficiency and optimal cut-off values of FeNO and IOS and spirometric parameters in predicting BHR. Optimal combinations of FeNO and IOS and spirometric parameters for BHR prediction were investigated using univariate and multivariate logistic regression models. Bootstrapping was employed for internal validation. Model discrimination and calibration were assessed using indices and calibration plots.

Results

Rhinitis and values of FeNO, IOS parameters (resonant frequency (Fres), reactance at 5 Hz (X5), and integrated area of low-frequency X (AX)) and spirometric parameters (FEV1, PEF, MEF₇₅, MEF₅₀, MEF₂₅, MMEF) were significantly different between patients with BHR and those without BHR (P < 0.05). After adjusting for rhinitis, logistic analyses showed that FeNO combined with Fres, FeNO combined with MMEF, or the combination of FeNO, Fres and MMEF had high predictive value in diagnosing BHR; the areas under the ROC curves (AUCs) of the corresponding three models were 0.914, 0.919 and 0.927, respectively. In addition, the three models displayed good discrimination, with high C-index values and good calibration.

Conclusion

FeNO combined with Fres or MMEF or a combination of these three parameters may be conveniently used as indicators in BHR prediction.

Long-acting muscarinic antagonists and small airways in asthma: Which link?

Involvement of small airways, those of <2 mm in internal diameter, is present in all stages of asthma and contributes substantially to its pathophysiologic expression. Therefore, small airways are a potential target to achieve optimal asthma control. Airway tone, which is increased in asthma, is mainly controlled by the vagus nerve that releases acetylcholine (ACh) and activates muscarinic ACh receptors (mAChRs) post-synaptically on airway smooth muscle (ASM). In small airways, M₃ mAChRs are expressed, but there is no vagal innervation. Non-neuronal ACh released from the epithelial cells that may express choline acetyltransferase in response to inflammatory stimuli, as well as from other structural cells in the airways, including fibroblasts and mast cells, can activate mAChRs. By antagonizing M₃ mAChR, the contraction of the ASM is prevented and, potentially, local inflammation can be reduced and the progression of remodeling may be averted. In fact, ACh also contributes to inflammation and remodeling of the airways and regulates the growth of ASM. Several experimental studies have demonstrated the potential benefit derived from the use of mAChR antagonists, mainly long-acting mAChR antagonists (LAMAs), on small airways in asthma. However, there are several confounding factors that may cause a wrong estimation of the relationship between LAMAs and small airways in asthma. Further studies are needed to differentiate broncholytic and anti-inflammatory effects of LAMAs and to better understand the interaction between LAMAs and corticosteroids, also in the context of a triple therapy that includes a β₂ -AR agonist, at different levels of the bronchial tree.

Seven Pillars of Small Airways Disease in Asthma and COPD: Supporting Opportunities for Novel Therapies

Identification of pathologic changes in early and mild obstructive lung disease has shown the importance of the small airways and their contribution to symptoms. Indeed, significant small airways dysfunction has been found prior to any overt airway obstruction being detectable by conventional spirometry techniques. However, most therapies for the treatment of obstructive lung disease target the physiological changes and associated symptoms that result from chronic lung disease, rather than directly targeting the specific underlying causes of airflow disruption or the drivers of disease progression. In addition, although spirometry is the current standard for diagnosis and monitoring of response to therapy, the most widely used measure, FEV1 , does not align with the pathologic changes in early or mild disease and may not align with symptoms or exacerbation frequency in the individual patient. Newer functional and imaging techniques allow more effective assessment of small airways dysfunction; however, significant gaps in our understanding remain. Improving our knowledge of the role of small airways dysfunction in early disease in the airways, along with the identification of novel end points to measure subclinical changes in this region (ie, those not captured as symptoms or identified through standard FEV1), may lead to the development of novel therapies that directly combat early airways disease processes with a view to slowing disease progression and reversing damage. This expert opinion paper discusses small airways disease in the context of asthma and COPD and highlights gaps in current knowledge that impede earlier identification of obstructive lung disease and the development and standardization of novel small airways-specific end points for use in clinical trials.

Intrabreath oscillometry is a sensitive test for assessing disease control in adults with severe asthma

BACKGROUND

Asthma control is not well reflected by spirometry, yet this is the most frequently used measure of lung function in asthma clinics. Oscillometry is an alternative technique suitable for those with severe asthma.

OBJECTIVE

To investigate usefulness of oscillometry in subjects with severe asthma to determine which outcome variables best reflected asthma control.

METHODS

Adults with severe asthma were recruited from a severe asthma clinic in Brazil. Oscillometry (conventional multifrequency measurements between 6 and 32 Hz; intrabreath tracking at 8 Hz) and spirometry were performed. Asthma control was determined by the asthma control test.

RESULTS

A total of 60 adults were evaluated; mean age was 56.7 years. There was predominance of women (82%), and most patients (63%) reported onset of asthma symptoms in childhood or adolescence. There were no differences between controlled and uncontrolled asthma in spirometry. Uncontrolled asthma was associated with higher resistance (at 8 and 10 Hz) and more negative reactance (for 6, 8, and 10 Hz) (P < .05) on conventional oscillometry. Intrabreath oscillometry revealed significant differences between controlled and uncontrolled patients with asthma (P < .01 for changes in resistance and reactance between end expiration and end inspiration). The accuracy of the lung function tests in discriminating between controlled and uncontrolled asthma was higher for intrabreath variables (area under the curve = 0.65-0.72).

CONCLUSION

Oscillometry, particularly the intrabreath technique, better reflected asthma control than spirometry measures. Our findings suggest that oscillometry may be a useful technique to aid management of severe asthma, with a potential to reflect loss of disease control.

Quantitative CT Analysis of Small Airway Remodeling in Patients with Chronic Obstructive Pulmonary Disease by a New Image Post-Processing System

Purpose

To explore a practical marker for quantitatively analyzing the small airway remodeling in COPD by HRCT.

Patients and Methods

Twenty-four patients with COPD (GOLD I, n = 7; GOLD II, n = 8; GOLD III+IV, n = 9) and 14 healthy controls (7 normal pulmonary function; 7 small-airway disease (SAD)) were enrolled in the study as five groups, GOLD I, GOLD II, GOLD III+IV, normal and SAD. All subjects underwent HRCT and spirometry. With ISP 9.0, whole emphysema index (EI) and the airway parameters, including wall area (WA), lumen area (LA), airway area (AA) of the 3rd, 5th and 9th generations of bronchi, were measured successively. The ratio of LA/AA and WA/AA in the 3rd, 5th and 9th generations of bronchi were calculated and compared among groups.

Results

For the five groups, EI was increased only in GOLD III+IV group (P < 0.05), while the ratio of LA/AA (9-LA/AA) and WA/AA (9-WA/AA) in 9th generation of bronchi have significantly changed since SAD group (P < 0.05). There were significant correlation between FEV₁generations of bronchi (r3 = 0.429, r5 = 0.583, r9 = 0.592, respectively, P < 0.05); FEV₁% and WA/AA (r3 = –0.428, r5 = –0.532, r9 = –0.570, respectively, P < 0.05); as well as MMEF% and LA/AA (r3 = 0.421, r5 = 0.566, r9 = 0.610, respectively, P < 0.05); MMEF% and WA/AA (r3 = –0.421, r5 = –0.529, r9 = –0.593, respectively, P < 0.05).

Conclusion

Small airway remodeling has occurred in the early stage of COPD, while emphysema in the late stage of COPD. The 9-LA/AA and 9-WA/AA are accurate and practical markers for small airway remodeling of COPD.

Small Airways Dysfunction and Bronchial Hyper-Responsiveness in Cough Variant Asthma

Background

Cough variant asthma (CVA) is one kind of atypical asthma. The study was to compare spirometric parameters of small airways and the degree of bronchial hyper-responsiveness (BHR) between CVA and classic asthma (CA), and examine the relationship between BHR and small airways to determine the accuracy of these markers as indicators of CVA.

Methods

A total of 825 asthmatic patients were screened for the study, and 614 were included. All patients performed spirometry and underwent a bronchial challenge with methacholine.

Results

The number of small airways dysfunctions in the CVA group was less than those of the CA group with MMEF% predicted (70% vs 80.91%, P=0.002) and FEF_50% predicted (62.71% vs 73.5%, P=0.004). The degree of small airways dysfunction was less in the CVA group compared with the CA group (P<0.001). Significant positive correlations were observed between the FEV₁ level below 20% of the baseline value (PD₂₀) and MMEF% predicted (r=0.282, P<0.001), FEF_50% predicted (r=0.2522, P<0.001), and FEF_75% predicted (r=0.2504, P<0.001) in patients with CVA. The area under curve (AUC) of MMEF, FEF₅₀, and FEF₇₅ (% predicted) was 0.615, 0.621, and 0.606, respectively. In addition, 0.17 mcg of PD₂₀ was the best diagnostic value for CVA, with an AUC of 0.582 (P=0.001).

Conclusion

Small airway dysfunction is milder in CVA. The value of BHR combined with small airways in CVA prediction, which was significant, but not enough to be clinically useful.

Small Airway Disease in Pediatric Asthma: the Who, What, When, Where, Why, and How to Remediate. A Review and Commentary

Asthma affects all portions of the airways. Small airways, however, comprise a substantial component of the conducting lung air flow. In asthma, inflammatory processes can affect the whole respiratory tract, from central to peripheral/small airways. The emphasis in adult and pediatric respiratory disease clinics is to focus on large airway obstruction and reversibility. This information, although valuable, underemphasizes a large portion of the conduction airway of asthmatics. Standard descriptions of asthma management focus on a multiple medication approaches. We particularly focused on the management of asthma in the international guidelines for the Global Initiative for Asthma (GINA). Overall, however, minimal attention is placed on the small airway pool in asthma medical management. We took the opportunity to thoroughly review and present specific data from the adult asthma literature which supported the concept that small airway abnormalities may play a role in the pathogenesis and clinical expression of asthma. Based on the conclusions of the adult asthma literature, we here present a thorough review of the literature as it relates to small airway disease in children with asthma. We used, collectively, individual data sources of data to expand the information available from standard diagnostic techniques, especially spirometry, in the evaluation of small airway disease. As the pharmacological approaches to moderate to severe asthma are advancing rapidly into the realm of biologics, we sought to present potential pharmacological options for small airway dysfunction in pediatrics prior to biological modifier intervention.

Pediatric pulmonology year in review 2019: Physiology

Pulmonary physiologic assessments are critical for the care and study of pediatric respiratory disease. In 2019, there were numerous contributions to this topic in Pediatric Pulmonology.

Predicting asthma exacerbation by impulse oscillometry evaluation of small airway function and fractional exhaled nitric oxide in preschool children

OBJECTIVE

To study impulse oscillometry (IOS) indices of peripheral airway function and FeNO as predictors of future loss of asthma control in preschool children.

METHODS

Patients aged 3 to 6 years who were actively being treated for asthma and children without asthma were enrolled in the study. Participants had no change in medication on visit 1 and returned for a follow-up visit within 8 to 12 weeks. At the first visit, nursing assessment, symptom history, IOS analysis, FeNO, and physician evaluation were repeated.

RESULTS

Fifty-one (64.6%) subjects had lost asthma control (UC-Group) and 28 (35.4%) subjects had maintained asthma control (C-Group) at their follow-up visit. Thirty-two children without asthma were enrolled in the study as a normal control group (N-Group). R5, R5-20, AX, and Z5 values were all significantly higher in subjects whose symptoms remained uncontrolled compared with those in the controlled asthma group (P < .01) and also significantly higher than those in the normal control group (P < .01). FeNO showed no significant difference between the UC-Group and C-Group (P = .399). Four indices-R5, R5-20, AX, and Z5-had an estimated area under the curve (AUC) of greater than 0.8 and were thus easily able to distinguish the UC-Group from the C-Group.

CONCLUSIONS

AX had the highest overall AUC (0.884) of the investigated parameters, and the optimal cut-off point of 37.435 cm H₂ O/L was able to predict future loss of asthma control in preschool children.

Volumetric capnography versus spirometry for the evaluation of pulmonary function in cystic fibrosis and allergic asthma

OBJECTIVE

To compare the values of the markers for volumetric capnography and spirometry and their ability to classify children and adolescents with asthma, cystic fibrosis (CF), and healthy controls.

METHODS

This was a cross-sectional study that included 103 patients with controlled persistent allergic asthma, 53 with CF and a healthy control group with 40 volunteers (aged 6 to 15 years), of both sexes. The individuals underwent volumetric capnography and spirometry.

RESULTS

Phase III slope (SIII), SIII standardized by exhaled tidal volume (SIII/TV) and capnographic index (SIII/SII)×100 (KPIv) were different among the three groups assessed, with highest values for CF. The relation between the forced expiratory volume in one second and the forced vital capacity (FEV₁/FVC) was the only spirometric marker that presented difference on the three groups. On individuals with normal spirometry, KPIv and FEV₁/FVC were different among the three groups. The ROC curve identified the individuals with asthma or CF from the control group, both through volumetric capnography (better to identify CF in relation to the control using KPIv) and through spirometry (better to identify asthma in relation to the control). KPIv was the best parameter to distinguish asthma from CF, even in individuals with normal spirometry.

CONCLUSION

Volumetric capnography and spirometry identified different alterations in lung function on asthma, CF, and healthy controls, allowing the three groups to be distinguished.

Changes in airway diameter and mucus plugs in patients with asthma exacerbation

Background

Airway obstruction due to decreased airway diameter and increased incidence of mucus plugs has not been directly observed in asthma exacerbation. We studied the changes in the inner diameter of the airway (Din) and the frequency of mucus plugs by airway generation in patients with asthma exacerbation. We compared these patients to those in a stable phase using high-resolution computed tomography (HRCT).

Methods and findings

Thirteen patients with asthma were studied by HRCT during asthma exacerbation and in a stable period. The HRCT study was performed on patients who could safely hold their breath for a short while in a supine position 1 hour after initial treatment for asthma exacerbation. Using a curved multiplanar reconstruction (MPR) software, we reconstructed the longitudinal airway images and the images exactly perpendicular to the airway axis to measure the Din and mucus plugs from the second- (segmental) to sixth-generation bronchi in all segments of the lungs.The ratios of Din (exacerbation/stable) were 0.91(P = 0.016), 0.88 (P = 0.002), 0.83 (P = 0.001), 0.80 (P = 0.001), and 0.87 (NS) in the second-, third-, fourth-, fifth-, and sixth-generation bronchi, respectively. The percentages of airway obstruction due to mucus plugs were notably higher in the fourth- and fifth-generation bronchi (17.9%/18.1% in stable phase and 43.2%/45.9% in the exacerbation phase, respectively) than in the other generations of bronchi.

Conclusions

Among the bronchi examined, the fourth- and fifth-generation bronchi were significantly obstructed during asthma exacerbation compared with the stable phase in terms of a decreased airway diameter and mucus plugs.

Efficacy and Safety of a Pressurized Metered-Dose Inhaler in Older Asthmatics: Comparison to a Dry Powder Inhaler in a 12-Week Randomized Trial

Purpose

Asthma control in older asthmatics is often less effective, which may be attributed to small airway dysfunction and poor inhalation technique. We compared the efficacy of 2 inhalers (fluticasone propionate/formoterol treatment using a pressurized metered-dose inhaler [p-MDI group] vs. fluticasone propionate/salmeterol treatment using a dry powder inhaler [DPI group]) in older asthmatics.

Methods

We conducted a 12-week, randomized, open-label, parallel-designed trial in older patients (over 55 years old) with moderate-to-severe asthma, and compared the efficacy and safety for asthma control between the 2 groups. Subgroup analyses on disease duration and air trapping were performed. Clinical parameters, including changes in lung function parameters, inhaler technique and adherence, were compared with monitoring adverse reactions between the 2 groups.

Results

A total of 68 patients underwent randomization, and 63 (30 in the p-MDI group and 33 in the DPI group) completed this study. The p-MDI group was non-inferior to the DPI group with regard to the rate of well-controlled asthma (53.3% vs. 45.5%, P < 0.001; a predefined non-inferiority limit of 17%). In subgroup analyses, the proportion of patients who did not reach well-controlled asthma in the p-MDI group was non-inferior to that in the DPI group; the difference was 12.7% among those with a longer disease duration (≥ 15 years) and 17.5% among those with higher air-trapping (RV/TLC ≥ 45%), respectively (a predefined non-inferiority limit of 17%, P < 0.001). No significant differences were observed in lung function parameters, inhalation techniques, adherence and adverse reactions between the 2 groups.

Conclusion

These results suggest that the p-MDI group may be comparable to the DPI group in the management of older asthmatics in aspects of efficacy and safety.

Concurrent absorption and secretion of airway surface liquids and bicarbonate secretion in human bronchioles

Although small airways account for the largest fraction of the total conducting airway surfaces, the epithelial fluid and electrolyte transport in small, native airway epithelia has not been well characterized. Investigations have been limited, no doubt, by the complex tissue architecture as well as by its inaccessibility, small dimensions, and lack of applicable assays, especially in human tissues. To better understand how the critically thin layer of airway surface liquid (ASL) is maintained, we applied a "capillary"-Ussing chamber (area ≈1 mm2) to measure ion transport properties of bronchioles with diameters of ~2 mm isolated from resected specimens of excised human lungs. We found that the small human airway, constitutively and concurrently, secretes and absorbs fluid as observed in porcine small airways (50). We found that the human bronchiolar epithelium is also highly anion selective and constitutively secretes bicarbonate ( HCO 3 - ), which can be enhanced pharmacologically by cAMP as well as Ca2+-mediated agonists. Concurrent secretion and absorption of surface liquid along with HCO 3 - secretion help explain how the delicate volume of the fluid lining the human small airway is physiologically buffered and maintained in a steady state that avoids desiccating or flooding the small airway with ASL.

Asthma control in preschool children with small airway function as measured by IOS and fractional exhaled nitric oxide

OBJECTIVE

This study investigated the accuracy of impulse oscillometry (IOS) combined with fractional exhaled nitric oxide (FeNO) to assess asthma control among preschool children.

METHODS

A total of 79 preschool children(3-6 year old) with asthma and 25 healthy preschool children who visited a paediatrician were enrolled in this study. All of the children were tested for allergens, respiratory system resistance (at 5 and 20 Hz [R5, R20]), respiratory system reactance (at 5 Hz [X5]), the resonant frequency of reactance (Fres), and the area under the reactance curve (between 5 Hz and Fres (reactance area [AX]) using IOS and FeNO. A paediatric respiratory specialist who was unaware of the IOS and FeNO results assigned children with asthma to either the asthma-controlled group (n = 27) or the asthma-uncontrolled group (n = 52) based on the Global Initiative for Asthma (GINA) criteria. A healthy control group (n = 25) was also included. The relationships between the FeNO and IOS values as well as the asthma control of the three groups were analysed, and the areas under the curve (AUCs) were calculated for each measure.

RESULTS

(1) During the controlled group, means±standard deviations of AX, R5-20, R5, X5 and FeNO were 26.15 ± 7.534, 3.52 ± 1.311,9.97 ± 1.576,-3.85 ± 0.572,-3.85 ± 0.572. During the uncontrolled group, means±standard deviations of AX,R5-20,R5,X5 and FeNO were 38.34 ± 13.563,5.36 ± 1.545,11.41 ± 2.029,-5.07 ± 1.554,36.40 ± 21.07. Among preschool children, significant differences were observed between the controlled and uncontrolled group with regard to the small airway functional parameters (AX, R5-20, R5, and X5) and FeNO(P <0.05).(2) A receiver operating characteristic (ROC) analysis showed that the AUCs were 0.786 for FeNO alone, 0.751 for X5 alone, and 0.866 for X5 combined with FeNO (cut-off value: 27 ppb).

CONCLUSION

FeNO combined with the small airway function parameter X5 accurately assessed asthma control among preschool children.

Is there room for further innovation in inhaled therapy for airways disease?

Inhaled medication is the cornerstone in the treatment of patients across a spectrum of respiratory diseases including asthma and chronic obstructive pulmonary disease. The benefits of inhaled therapy have long been recognised but the most important innovations have occurred over the past 60 years, beginning with the invention of the pressurised metered dose inhaler. However, despite over 230 different device and drug combinations currently being available, disease control is far from perfect. Here we look at how innovation in inhaler design may improve treatments for respiratory diseases and how new formulations may lead to treatments for diseases beyond the lungs. We look at the three main areas where innovation in inhaled therapy is most likely to occur: 1) device engineering and design; 2) chemistry and formulations; and 3) digital technology associated with inhalers. Inhaler design has improved significantly but considerable challenges still remain in order to continually innovate and improve targeted drug delivery to the lungs. Healthcare professionals want see innovations that motivate their patients to achieve their goal of improving their health, through better adherence to treatment. Patients want devices that are easy to use and to see that their efforts are rewarded by improvements in their condition.

KEY POINTS

The dictionary definition of innovation is the introduction of new things, ideas or ways of doing something. We show how this definition can be applied to inhaled therapy.We take a look at the past to see what drove innovation in inhaler design and how this has led to the current devices.We look at the current drivers of innovation in engineering, chemistry and digital technology and predict how this may translate to new devices.Can innovation help the healthcare professional manage their patients better?What does the patient expect from innovation in their device?

EDUCATIONAL AIMS

To understand the importance of inhaled medication in the treatment of lung diseases.To understand how innovation has helped advance some of the devices patients use today from basic and inefficient designs.To understand the obstacles that prevent patients from receiving optimal treatment from their inhalers.To understand how innovation in inhaler design can lead to improved treatment for patients and widen the range of diseases that can be treated via the inhaled route.

Lung function parameters in omalizumab responder patients: An interesting tool?

BACKGROUND

Omalizumab, an anti-IgE antibody, is used to treat patients with severe allergic asthma. The evolution of lung function parameters over time and the difference between omalizumab responder and nonresponder patients remain inconclusive. The objective of this real-life study was to compare the changes in forced expiratory volume in 1 second (FEV1) of omalizumab responders and nonresponders at 6 months.

METHODS

A multicenter analysis was performed in 10 secondary and tertiary institutions. Lung function parameters (forced vital capacity (FVC), pre- and postbronchodilator FEV1, residual volume (RV), and total lung capacity (TLC) were determined at baseline and at 6 months. Omalizumab response was assessed at the 6-month visit. In the omalizumab responder patients, lung function parameters were also obtained at 12, 18, and 24 months.

RESULTS

Mean prebronchodilator FEV1 showed improvement in responders at 6 months, while a decrease was observed in nonresponders (+0.2±0.4 L and -0.1±0.4 L, respectively, P<.01). After an improvement at 6 months, pre- and postbronchodilator FEV1 remained stable at 12, 18, and 24 months. The FEV1/FVC remained unchanged over time, but the proportion of patients with an FEV1/FVC ratio <0.7 decreased at 6, 12, 18, and 24 months (55.2%, 54.0%, 54.0%, and 44.8%, respectively, P<.05). Mean RV values decreased at 6 months but increased at 12 months and 24 months (P<.05). Residual volume/total lung capacity (RV/TLC) ratio decreased at 6 months and remained unchanged at 24 months.

CONCLUSION

After omalizumab initiation, FEV1 improved at 6 months in responder patients and then remained stable for 2 years. RV and RV/TLC improved at 6 months.

[Comparison of functional parameters of small airways between patients with typical asthma and cough-variant asthma]

OBJECTIVE

To compare the functional parameters of the small airways and clinical characteristics between patients with typical asthma (TA) and cough-variant asthma (CVA).

METHODS

Forty-three newly diagnosed asthmatic patients were enrolled, including 15 with TA and positive bronchial provocation test [TA BPT(+)], 12 with TA and positive bronchial dilation test [TA BDT(+)] and 16 with CVA, and 27 healthy subjects served as the control group. All the subjects were required to complete data acquisition, asthma control test, asthma control test scale, fractional exhaled nitric oxide, airway resistance and pulmonary function tests, BPT or BDT.

RESULTS

The interval from onset to a definite diagnosis of TA BDT(+) was longer than that of TA BPT(+), while that of CVA was the shortest (P=0.022). The pulmonary functional parameters of TA BDT (+) was significantly lower than those of the other 3 groups (P<0.05). MMEF, MEF₇₅, MEF₅₀, and MEF₂₅ in patients with TA BDT(+), TA BPT(+) and CVA were significantly lower than those in the control group (P<0.01). The resonant frequency, respiratory impedance, resistance at 5 Hz, resistance at 20 Hz, and reactance at 5 Hz were significant higher in patients with TA BDT (+) than in the control subjects, while these parameters showed no significant differences among TA BPT (+), CVA and control groups. The airway resistance in TA BPT(+), CVA, and control groups increased after BPT, and the patients with TA BPT(+) showed greater changes in airway resistance than those in CVA and control groups. In CVA patients, FeNO showed a strong positive correlation with respiratory impedance (r=0.523, P=0.038), resistance at 5 Hz (r=0.542, P=0.030), and resistance at 20 Hz (r=0.524, P=0.037), and the airway responsiveness showed a strong positive correlation with resistance at 20 Hz (Rho=-0.512, P=0.043).

CONCLUSION

CVA is the early stage of TA, and CVA, TA BPT(+), and TA BDT(+) may represent different stages of asthma. Uncontrolled, prolonged CVA may evolve into TA BPT (+), whose further progression can cause damages of the pulmonary function and small airway function and leads eventually to TA BDT (+).

Recognition of Small Airways Obstruction in Asthma and COPD - The Road Less Travelled

The small airways, once regarded as the silent zone in the air conducting system of the lungs are now known to be one of the initial sites of involvement in diseases like asthma and Chronic Obstructive Pulmonary Disease (COPD). Identification of the involvement of distal airways in these diseases is often difficult to assess, clinically as well as by conventional pulmonary function tests and therefore, usually remains undiscovered in early stages. Early recognition of their involvement in asthma and COPD and timely management may reduce long term morbidity in these conditions. This article aims to highlight the relatively lesser recognized facts about small airways involvement in asthma and COPD and role of imaging and newer modalities for detection.

Systemic and mucosal pre-administration of recombinant Helicobacter pylori neutrophil-activating protein prevents ovalbumin-induced allergic asthma in mice

PURPOSE

Previous epidemiologic studies have demonstrated an inverse association between Helicobacter pylori infection and the frequency of allergic asthma. The neutrophil-activating protein (NAP) of H. pylori has been identified as a modulator possessing anti-Th2 inflammation activity. Here, we sought to determine whether systemic or mucosal pre-administration of recombinant H. pylori NAP (rNAP) could prevent ovalbumin (OVA)-induced allergic asthma in mice.

METHODS

Mice were exposed to purified rNAP through intraperitoneal injection or inhalation and then sensitized with OVA. Following a challenge with aerosolized OVA, the bronchoalveolar lavage fluid (BALF) cell count, lung tissue histology, BALF cytokines and serum IgE were evaluated.

RESULTS

Both intraperitoneal injection and inhalation of rNAP prior to OVA sensitization significantly reduced eosinophil accumulation and inflammatory infiltration in lung tissue in OVA-induced asthma mice; eosinophils were reduced in the BALF of rNAP-treated mice. In addition, IL-4 and IL-13 levels were lower (P < 0.01), IL-10 and IFN-γ levels were higher (P < 0.01) and IgE serum levels were lower (P < 0.01) in the treated groups compared to the control group.

CONCLUSIONS

Systemic and mucosal pre-administration of rNAP could suppress the development of OVA-induced asthma in mice; rNAP may be utilized as part of novel strategies for the prevention or treatment of allergic diseases.

Inhibitory Effects of Resveratrol on Airway Remodeling by Transforming Growth Factor-β/Smad Signaling Pathway in Chronic Asthma Model

Purpose

Asthma is a chronic airway disease characterized by airway remodeling, leading to a progressive decline in lung function. Therapeutic agents that attenuate airway remodeling can complement the limited effects of traditional glucocorticoids. In this study, we investigated the effect of resveratrol on allergic airway inflammation and remodeling in a murine model of chronic bronchial asthma.

Methods

Peribronchial smooth muscle thickening that developed in mice challenged with a 3-month repeated exposure to ovalbumin (OVA) was used to study airway remodeling. Oral resveratrol was administered daily during the OVA challenge. The expression of TGF-β1/Smad signaling proteins and downstream mesenchymal markers in the presence or absence of resveratrol was examined in bronchial epithelial cells.

Results

OVA sensitization and chronic challenge increased airway hyperresponsiveness, inflammation, goblet cell hyperplasia, α-smooth muscle actin (SMA), and collagen deposition. Resveratrol effectively suppressed OVA-induced airway inflammation and remodeling. The expression of TGF-β1/phosphorylated Smad2/3 was increased in the lung tissues of OVA-challenged mice but effectively inhibited by resveratrol. In bronchial epithelial cells, the TGF-β1-induced expression of the mesenchymal markers snail, slug, vimentin, and α-SMA was suppressed by resveratrol treatment.

Conclusions

Resveratrol effectively ameliorated both airway inflammation and airway structural changes in a mouse model of bronchial asthma. These effects were mediated by decreased TGF-β1 expression, in turn suppressing TGF-β1/Smad signaling and the epithelial-mesenchymal transition process. Our results demonstrate the potential benefits of resveratrol for the treatment of airway remodeling associated with bronchial asthma.

Asthma-Related Outcomes in Patients Initiating Extrafine Ciclesonide or Fine-Particle Inhaled Corticosteroids

Purpose

Extrafine-particle inhaled corticosteroids (ICS) have greater small airway deposition than standard fine-particle ICS. We sought to compare asthma-related outcomes after patients initiated extrafine-particle ciclesonide or fine-particle ICS (fluticasone propionate or non-extrafine beclomethasone).

Methods

This historical, matched cohort study included patients aged 12-60 years prescribed their first ICS as ciclesonide or fine-particle ICS. The 2 cohorts were matched 1:1 for key demographic and clinical characteristics over the baseline year. Co-primary endpoints were 1-year severe exacerbation rates, risk-domain asthma control, and overall asthma control; secondary endpoints included therapy change.

Results

Each cohort included 1,244 patients (median age 45 years; 65% women). Patients in the ciclesonide cohort were comparable to those in the fine-particle ICS cohort apart from higher baseline prevalence of hospitalization, gastroesophageal reflux disease, and rhinitis. Median (interquartile range) prescribed doses of ciclesonide and fine-particle ICS were 160 (160-160) µg/day and 500 (250-500) µg/day, respectively (P<0.001). During the outcome year, patients prescribed ciclesonide experienced lower severe exacerbation rates (adjusted rate ratio [95% CI], 0.69 [0.53-0.89]), and higher odds of risk-domain asthma control (adjusted odds ratio [95% CI], 1.62 [1.27-2.06]) and of overall asthma control (2.08 [1.68-2.57]) than those prescribed fine-particle ICS. The odds of therapy change were 0.70 (0.59-0.83) with ciclesonide.

Conclusions

In this matched cohort analysis, we observed that initiation of ICS with ciclesonide was associated with better 1-year asthma outcomes and fewer changes to therapy, despite data suggesting more difficult-to-control asthma. The median prescribed dose of ciclesonide was one-third that of fine-particle ICS.

Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN)

Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases.

Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA²LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change.

The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction.

In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 μm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant.

Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician’s considerations of disease features, phenotype, and response to previous therapy.

This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.

Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN)

Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases.

Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA²LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change.

The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction.

In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 μm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant.

Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician’s considerations of disease features, phenotype, and response to previous therapy. This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.

Clinical potential of oligonucleotide-based therapeutics in the respiratory system

The discovery of an ever-expanding plethora of coding and non-coding RNAs with nodal and causal roles in the regulation of lung physiology and disease is reinvigorating interest in the clinical utility of the oligonucleotide therapeutic class. This is strongly supported through recent advances in nucleic acids chemistry, synthetic oligonucleotide delivery and viral gene therapy that have succeeded in bringing to market at least three nucleic acid-based drugs. As a consequence, multiple new candidates such as RNA interference modulators, antisense, and splice switching compounds are now progressing through clinical evaluation. Here, manipulation of RNA for the treatment of lung disease is explored, with emphasis on robust pharmacological evidence aligned to the five pillars of drug development: exposure to the appropriate tissue, binding to the desired molecular target, evidence of the expected mode of action, activity in the relevant patient population and commercially viable value proposition.

Study on small airway function in asthmatics with fractional exhaled nitric oxide and impulse oscillometry

OBJECTIVES

The invasive techniques can be direct and objective to assess small airway function, but they have significant risks and inconveniences for patients and cannot be repeated often. Some sophisticated techniques such as fractional exhaled nitric oxide (FeNO) and impulse oscillometry (IOS) may surmount such restrictions. Therefore, we investigated the relation among FeNO, IOS, and small airway function in asthmatic patients.

METHODS

We recruited 140 asthmatic patients including 69 patients with small airway normal function and 71 patients with small airway dysfunction. FeNO, eosinophil（EOS）count and total immunoglobulin E (IgE) in peripheral blood, pulmonary function, as well as IOS were measured.

RESULTS

The levels of FeNO, the reactance area (AX), the resonant frequency Fres and EOS were significantly increased in small airway dysfunction group compared with small airway normal function group (P < 0.01 respectively). A multiple regression model showed that FeNO, AX and Fres were correlative factors of mid forced expiratory flow of percentages of predicted values [FEF25-75 (%pred)] (P < 0.01, respectively). A receiver operating characteristic (ROC) analysis showed that the combination of FeNO, AX and Fres had a greater area under the ROC curve (AUC) than each of them (AUC: 0.881, P < .001, 95％CI: 0.815-0.929).

CONCLUSION

FeNO and IOS are helpful in diagnosis of small airway dysfunction with high sensitivity and specificity, and FeNO combined with IOS can better evaluate the small airway function in asthmatic patients.

Dilemmas, Confusion, and Misconceptions Related to Small Airways Directed Therapy

During the past decade, there has been increasing evidence that the small airways (ie, airways < 2 mm in internal diameter) contribute substantially to the pathophysiologic and clinical expression of asthma and COPD. The increased interest in small airways is, at least in part, a result of innovation in small-particle aerosol formulations that better target the distal lung and also advanced physiologic methods of assessing small airway responses. Increasing the precision of drug deposition may improve targeting of specific diseases or receptor locations, decrease airway drug exposure and adverse effects, and thereby increase the efficiency and effectiveness of inhaled drug delivery. The availability of small-particle aerosols of corticosteroids, bronchodilators, or their combination enables a higher total lung deposition and better peripheral lung penetration and provides added clinical benefit, compared with large-particle aerosol treatment. However, a number of questions remain unanswered about the pragmatic approach relevant for clinicians to consider the role of small airways directed therapy in the day-to-day management of asthma and COPD. We thus have tried to clarify the dilemmas, confusion, and misconceptions related to small airways directed therapy. To this end, we have reviewed all studies on small-particle aerosol therapy systematically to address the dilemmas, confusion, and misconceptions related to small airways directed therapy.

Omalizumab Improves Quality of Life and Asthma Control in Chinese Patients With Moderate to Severe Asthma: A Randomized Phase III Study

Purpose

Omalizumab is the preferred add-on therapy for patients with moderate-to-severe persistent allergic asthma and has demonstrated efficacy and safety in various ethnicities. This study evaluated the efficacy and safety of omalizumab in Chinese patients with moderate-to-severe allergic asthma.

Methods

This randomized, double-blind, parallel-group, placebo-controlled, phase III study assessed lung function, quality of life, asthma control, and safety of omalizumab after 24-week therapy in Chinese patients (18-75 years of age).

Results

A total of 616 patients were randomized (1:1) to omalizumab or placebo. The primary endpoint, least squares mean treatment difference (LSM-TD) in morning peak expiratory flow (PEF) (omalizumab vs placebo), at Weeks >20-24 was 8.85 L/min (Full analysis set; P=0.062). Per-protocol analysis set showed significant improvements with LSM-TD of 11.53 L/min in mean mPEF at Weeks >20-24 (P=0.022). The FEV1 % predicted was significantly improved with omalizumab vs placebo from 8 to 24 weeks (after 24-week treatment: LSM-TD=4.12%; P=0.001). At Week 24, a higher proportion of omalizumab-treated patients achieved clinically relevant improvements in standardized AQLQ (58.2% vs 39.3%; LSM=0.51 vs 0.10; P<0.001) and ACQ (49.5% vs 35.5%; LSM=-0.51 vs -0.34; P=0.002) scores vs placebo. Total and nighttime symptom scores reduced significantly with omalizumab vs placebo (LSM-TD=-0.21, P=0.048 and -0.12, P=0.011, respectively). Although the study was not powered to study differences in exacerbation rates (P=0.097), exacerbations in winter months were less frequent in the omalizumab vs placebo group (2 vs 21). Adverse event and severe adverse event rates were comparable between omalizumab and placebo.

Conclusions

Omalizumab improves lung function, quality of life, and asthma control in Chinese patients with moderate-to-severe persistent allergic asthma and has a good safety profile.

Small airway dysfunction and bronchial asthma control : the state of the art

According to national and international guidelines, achieving and maintaining asthma control is a major goal of disease management. In closely controlled clinical trials, good asthma control can be achieved , with the medical treatments currently available, in the majority of patients , but large population-based studies suggest that a significant proportion of patients in real-life setting experience suboptimal levels of asthma control and report lifestyle limitations with a considerable burden on quality of life. Poor treatment adherence and persistence, failure to use inhalers correctly, heterogeneity of asthma phenotypes and associated co-morbidities are the main contributing factors to poor disease control. Now, it is widely accepted that peripheral airway dysfunction , already present in patients with mild asthma, is a key contributor of worse control. The aim of this paper is to investigate the association between small-airways dysfunction and asthma symptoms/control. We therefore performed a PubMed search using keywords : small airways; asthma (limits applied: Humans, English language) and selected papers with a study population of asthmatic patients, reporting measurement of small-airways parameters and clinical symptoms/control.

Can 'extrafine' dry powder aerosols improve lung deposition?

There is increasing interest in the use of so-called 'extrafine' aerosols to target the small airways in the management of asthma and COPD. Using previously presented deposition data, we assessed whether submicron (<1μm) particles can improve central and deep lung deposition. Our data show instead that particles in the range 1-3μm are much more relevant in this respect. Based on this finding the Symbicort Turbuhaler, Seretide Diskus, Rolenium Elpenhaler and Foster (Fostair) NEXThaler ICS/LABA combination DPIs were tested in vitro as a function of the pressure drop (2, 4 and 6kPa) across the inhaler. Obtained fine particle fractions (FPFs) <5μm (as percent of label claim) were divided into subfractions <1, 1-3 and 3-5μm. Differences of up to a factor of 4 were found between the best (Turbuhaler) and worst performing DPI (Elpenhaler), particularly for the FPF in the size range 1-3μm. The NEXThaler, described as delivering 'extrafine' particles, did not appear to be superior in this size range. The marked differences in amount and size distribution of the aerosols between the devices in this study must cause significant differences in the total lung dose and drug distribution over the airways.

Impact of treatment with inhaled corticosteroids on bone mineral density of patients with asthma: related with age

The effect of inhaled corticosteroid on bone mineral density (BMD) was investigated in 44 asthmatic patients after median treatment duration of 6.5 years. Compared with controls, BMD decreased only in patients aged <50 years in both the spine (11.3 %, p = 0.013) and hip (8.8 %, p = 0.044), whereas in patients ≥50 years BMD did not decrease significantly.

INTRODUCTION

The results of studies which addressed the impact of inhaled corticosteroid (ICS) therapy on BMD of patients with asthma are conflicting. This case-control study aimed to compare BMD status in ICS user with asthma with healthy controls according to age.

METHODS

BMD at the lumbar spine (LS), femoral neck (FN) was measured by dual energy X-ray absorptiometry (DEXA). Patients and controls were compared according to BMD gr/cm(2), BMD T-score, BMD Z-score, frequency of osteoporosis (defined as BMD T-score ≤-2.5), and frequency of patients with BMD Z-score <-1 at LS and FN with regard to age <50 and ≥50 years old.

RESULTS

Forty-four ICS user patients (females 63.6 %) with median treatment duration of 6.5 years and 50 controls (females, 69.4 %) with respective mean age of 49.2 ± 9.5 and 47.4 ± 10.5 years (p = 0.38 and p = 0.35) entered the study. Overall LS-BMD and FN-BMD gr/cm2 in total patients were lower than in controls by 6 % (p = 0.065) and 5.9 % (p = 0.09), respectively. In patients <50 years, mean LS-BMD gr/cm(2) was lower than controls by 11.3 % (p = 0.013) and FN-BMD by 8.8 % (p = 0.044). Mean BMD T-score and BMD Z-score in both measurement sites were also lower than controls (p = 0.013 and 0.01, respectively. Frequency of osteoporosis did not differ but frequency of patients with BMD Z-score <-1 was significantly higher in patients (odds ratio (OR) = 6.57 95 % CI, 1.8-23.9, p = 0.004). In age group ≥50 years old, reduction of BMD in both measurement sites did not reach to a significant level.

CONCLUSION

This study indicates that BMD reduction in ICS user with asthma is dependent on age and appears that younger patients are at greater risk of BMD loss. These findings suggest preventive measures particularly in patients <50 years.

The role of the small airways in the pathophysiology of asthma and chronic obstructive pulmonary disease

Chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), represent a major social and economic burden for worldwide health systems. During recent years, increasing attention has been directed to the role of small airways in respiratory diseases, and their exact contribution to the pathophysiology of asthma and COPD continues to be clarified. Indeed, it has been suggested that small airways play a distinct role in specific disease phenotypes. Besides providing information on small airways structure and diagnostic procedures, this review therefore aims to present updated and evidence-based findings on the role of small airways in the pathophysiology of asthma and COPD. Most of the available information derives from either pathological studies or review articles and there are few data on the natural history of small airways disease in the onset or progression of asthma and COPD. Comparisons between studies on the role of small airways are hard to draw because both asthma and COPD are highly heterogeneous conditions. Most studies have been performed in small population samples, and different techniques to characterize aspects of small airways function have been employed in order to assess inflammation and remodelling. Most methods of assessing small airways dysfunction have been largely confined to research purposes, but some data are encouraging, supporting the utilization of certain techniques into daily clinical practice, particularly for early-stage diseases, when subjects are often asymptomatic and routine pulmonary function tests may be within normal ranges. In this context further clinical trials and real-life feedback on large populations are desirable.

Biomarkers of inflammation in persons with chronic tetraplegia

In addition to lung volume restriction, individuals with chronic tetraplegia exhibit reduced airway caliber and bronchodilator responsiveness similar to persons with asthma. In asthma, airflow obstruction is closely linked to airway inflammation. Conversely, little is known regarding the airway inflammatory response in tetraplegia. To compare levels of biomarkers of inflammation in exhaled breath condensate (EBC) and serum in subjects with chronic tetraplegia, mild asthma, and able-bodied controls.Prospective, observational pilot study. Thirty-four subjects participated: tetraplegia (n = 12), asthma (n = 12), controls (n = 10). Biomarkers in EBC [8-isoprostane (8-IP), leukotriene B4 (LT-B4), prostaglandin E2 (PG-E2), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6)] and serum (8-IP, LT-B4, TNF-α, IL-6) were determined using commercially available EIA kits (Cayman Chemical Company, Ann Arbor, MI). Separate, one-way ANOVA with Bonferroni's post-hoc analyses were performed to determine group differences in demographic and dependent variables [EBC and serum biomarkers, fractional exhaled nitric oxide (FeNO), pulmonary function parameters, and specific airway conductance (sGaw)]. The tetraplegia group had significantly elevated 8-IP levels in EBC compared to the asthma (68 ± 38 versus 21 ± 13 pg ml(-1); p < 0.001) and control groups (22 ± 13 pg ml(-1); p < 0.01), respectively. FeNO levels were significantly elevated in the asthma compared to the control group (26 ± 18 versus 11 ± 4 ppb; p < 0.05), and trended higher than levels in the tetraplegia group (15 ± 6; p = 0.08). Levels of serum biomarkers did not differ significantly among groups. Through analysis of EBC, levels of 8-IP were significantly elevated compared to levels found in individuals with mild asthma and healthy controls. Further studies are needed to extend upon these preliminary findings that suggest the presence of airway inflammation in subjects with chronic tetraplegia, and how this relates to pulmonary dysfunction in this population.

A review of standard pharmacological therapy for adult asthma – Steps 1 to 5

The aim of pharmacological therapy for asthma is to improve symptoms and lung function and minimize the risk of asthma attacks. The intensity of treatment is based on the level of asthma control and the potential risk of future deterioration. In the British asthma guidelines, treatments are divided into steps 1 to 5, with each step signifying a need for an increase in therapy in response to symptoms or to prevent exacerbations. Treatments comprise of inhaled or systemic medications. Inhaled therapy includes short-acting and long-acting medication to improve symptoms and inhaled corticosteroids that reduce airway inflammation. Systemic treatments include medications that act on specific biological pathways, such as the leukotriene or immunoglobulin E pathways, or systemic corticosteroids. In choosing a particular therapy, treatment benefits are balanced by the potential risks of medication-related adverse effects. This review will provide a practical guide to the key pharmacological therapies for adult asthma at steps 1 to 5 based on British guidelines and consider future options for new treatments.