Inflammatory subtypes in cough-variant asthma: association with maintenance doses of inhaled corticosteroids

Microbiota Alterations in Lung, Ileum, and Colon of Guinea Pigs with Cough Variant Asthma

Alterations in the microbiota composition, or ecological dysbiosis, have been implicated in the development of various diseases, including allergic diseases and asthma. Examining the relationship between microbiota alterations in the host and cough variant asthma (CVA) may facilitate the discovery of novel therapeutic strategies. To elucidate the diversity and difference of microbiota across three ecological niches, we performed 16S rDNA amplicon sequencing on lung, ileum, and colon samples. We assessed the levels of interleukin-12 (IL-12) and interleukin-13 (IL-13) in guinea pig bronchoalveolar lavage fluid using the enzyme-linked immunosorbent assay (ELISA). We applied Spearman's analytical method to evaluate the correlation between microbiota and cytokines. The results demonstrated that the relative abundance, α-diversity, and β-diversity of the microbial composition of the lung, ileum, and colon varied considerably. The ELISA results indicated a substantial increase in the level of IL-13 and a decreasing trend in the level of IL-12 in the CVA guinea pigs. The Spearman analysis identified a correlation between Mycoplasma, Faecalibaculum, and Ruminococcus and the inflammatory factors in the CVA guinea pigs. Our guinea pig model showed that core microorganisms, such as Mycoplasma in the lung, Faecalibaculum in the ileum, and Ruminococcus in the colon, may play a crucial role in the pathogenesis of CVA. The most conspicuous changes in the ecological niche were observed in the guinea pig ileum, followed by the lung, while relatively minor changes were observed in the colon. Notably, the microbial structure of the ileum niche approximated that of the colon niche. Therefore, the results of this study suggest that CVA development is closely related to the dysregulation of ileal, lung, and colon microbiota and the ensuing inflammatory changes in the lung.

Asthma Phenotypes in the Era of Personalized Medicine

Asthma is a widespread disease affecting approximately 300-million people globally. This condition leads to significant morbidity, mortality, and economic strain worldwide. Recent clinical and laboratory research advancements have illuminated the immunological factors contributing to asthma. As of now, asthma is understood to be a heterogeneous disease. Personalized medicine involves categorizing asthma by its endotypes, linking observable characteristics to specific immunological mechanisms. Identifying these endotypic mechanisms is paramount in accurately profiling patients and tailoring therapeutic approaches using innovative biological agents targeting distinct immune pathways. This article presents a synopsis of the key immunological mechanisms implicated in the pathogenesis and manifestation of the disease's phenotypic traits and individualized treatments for severe asthma subtypes.

Identification of cough-variant asthma phenotypes based on clinical and pathophysiologic data

BACKGROUND

Cough-variant asthma (CVA) may respond differently to antiasthmatic treatment. There are limited data on the heterogeneity of CVA.

OBJECTIVE

We aimed to classify patients with CVA using cluster analysis based on clinicophysiologic parameters and to unveil the underlying molecular pathways of these phenotypes with transcriptomic data of sputum cells.

METHODS

We applied k-mean clustering to 342 newly physician-diagnosed patients with CVA from a prospective multicenter observational cohort using 10 prespecified baseline clinical and pathophysiologic variables. The clusters were compared according to clinical features, treatment response, and sputum transcriptomic data.

RESULTS

Three stable CVA clusters were identified. Cluster 1 (n = 176) was characterized by female predominance, late onset, normal lung function, and a low proportion of complete resolution of cough (60.8%) after antiasthmatic treatment. Patients in cluster 2 (n = 105) presented with young, nocturnal cough, atopy, high type 2 inflammation, and a high proportion of complete resolution of cough (73.3%) with a highly upregulated coexpression gene network that related to type 2 immunity. Patients in cluster 3 (n = 61) had high body mass index, long disease duration, family history of asthma, low lung function, and low proportion of complete resolution of cough (54.1%). TH17 immunity and type 2 immunity coexpression gene networks were both upregulated in clusters 1 and 3.

CONCLUSION

Three clusters of CVA were identified with different clinical, pathophysiologic, and transcriptomic features and responses to antiasthmatics treatment, which may improve our understanding of pathogenesis and help clinicians develop individualized cough treatment in asthma.

Inflammatory Phenotypes of Cough Variant Asthma as Response Predictors to Anti-Asthmatic Therapy

Background

Eosinophilic inflammatory phenotype was thought to be the most common phenotype of cough variant asthma (CVA), nevertheless other phenotypes were also reported.

Purpose

The study aimed to analyze the inflammatory phenotypes of CVA in relation to treatment response to the stepwise anti-asthmatic treatment.

Patients and Methods

The study included 45 patients with chronic cough (CC) and suspicion of CVA (normal chest X-ray, presence of bronchial hyperresponsiveness and no history of wheezing or dyspnea) in whom induced sputum was successfully collected. Based on the cellular composition of the sputum, patients were divided into major inflammatory phenotypes: eosinophilic, neutrophilic, paucigranulocytic or mixed granulocytic. A stepwise treatment, including inhaled corticosteroids with long-acting β₂-agonist, montelukast and short-term therapy with prednisone was initiated. Good treatment response was defined as the reduction in cough severity at least 20 mm from the baseline in visual analogue scale and improvement in cough-related quality of life assessed by the Leicester cough questionnaire at least 1.3 points after any of three steps.

Results

Finally, 40/45 (88.9%) patients improved after therapy. Eosinophilic asthma was found in 13/40 (32.5%) patients, neutrophilic in 6/40 (15.0%) and paucigranulocytic pattern in 21/40 (52.5%) patients. No one demonstrated a mixed granulocytic phenotype. The response to the treatment was similar in all groups. However, the reduction in cough severity was inversely related to the percentage of sputum neutrophils (r = −0.44, P = 0.003). We showed that the percentage of neutrophils in sputum >46% may be considered as a predictor of poor response to anti-asthmatic therapy.

Conclusion

The diversity of inflammatory phenotypes with paucigranulocytic preponderance was found in subjects with CVA. The response to anti-asthmatic treatment in patients with CVA was not related to the inflammatory phenotype. High neutrophil count in sputum may predict poor response to anti-asthmatic therapy in patients with CC and bronchial hyperresponsiveness.

Perspectives and Management of Atypical Asthma in Chinese Specialists and Primary Care Practitioners-A Nationwide Questionnaire Survey

Background and objective: To evaluate the awareness/knowledge and clinical practice for the treatment of atypical asthma among respiratory specialists and primary care practitioners (PCPs) in China.

Methods: A total number of 1,997 physicians participated in the survey via WeChat. The questionnaire included six main items: physician demographic characteristics, awareness, diagnosis, medical prescription, assessment/education, and proposal.

Results: Cough variant asthma (CVA) was recognized by 97.51% of physicians (1,166 respiratory specialists and 799 PCPs), followed by chest tightness variant asthma (CTVA, 83.72%) and occult asthma (73.54%). Specialists were more likely to follow diagnostic recommendations than PCPs (P < 0.01); however, 34.15% of physicians reported the utility of bronchodilation tests, airway provocation tests, and peak expiratory flow monitoring. A total of 91.70% and 92.01% of physicians prescribed inhaled corticosteroids (ICS) or ICS plus long-acting beta-agonists (LABA) for CVA and CTVA, respectively. Physicians prescribed an ICS or ICS/LABA for 4 (2–8) or 8 (4–12) weeks for CVA and 4 (2–8) or 5 (4–12) weeks for CTVA, and the prescription durations were significantly shorter for PCPs than for specialists (P < 0.01). Further, 52.42% and 35.78% reported good control of CVA and CTVA, respectively, with significantly lower control rates for PCPs than for specialists (P < 0.01). Additionally, specialists exhibited better assessment and educational habits than PCPs.

Conclusion: While atypical asthma was identified by most specialists and PCPs, there remains a gap between management in real clinical practice and guideline recommendations, especially for PCPs. Further training of PCPs and clinical studies of atypical asthma are required to improve practice.

Narrative Review: how long should patients with cough variant asthma or non-asthmatic eosinophilic bronchitis be treated?

The causes of chronic cough can be categorized into eosinophilic and noneosinophilic disorders, and approximately 30% to 50% of people with chronic cough have eosinophilic airway inflammation, the presence of which can be confirmed by sputum eosinophilia or elevated exhaled nitric-oxide levels. Cough variant asthma (CVA) is a phenotype of asthma which lacks wheezing or dyspnea, and consistently one of the most common causes of chronic cough worldwide. CVA and non-asthmatic eosinophilic bronchitis (NAEB) shares common feature such as chronic dry cough, eosinophilic inflammation, and development of chronic airflow obstruction (CAO) and asthma in a subset of patients. The distinctive characteristic of these conditions is the presence of airway hyperresponsiveness in CVA but not in NAEB. Coughing is responsive to bronchodilators such as beta-agonists in CVA, but such feature has not been clarified in NAEB. Inhaled corticosteroids (ICSs) are the first-line treatment, and leukotriene receptor antagonists are also effective, in patients with both CVA and NAEB. This review will give an outline of clinical and physiological features, and prognosis and its determinants of CVA and EBNA. Further, the rationale and evidence, despite limited, for the need of long-term treatment will be discussed. The development of airway remodeling due to mechanical stress to the airways exerted by long-standing coughing will also be discussed.

Therapeutic effects and mechanisms study of Hanchuan Zupa Granule in a Guinea pig model of cough variant asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Hanchuan Zupa Granule (HCZP), a traditional Chinese ethnodrug, has the functions of supressing a cough, resolving phlegm, warming the lungs, and relieving asthma. In clinical practice employing traditional Chinese medicine (TCM), HCZP is commonly used to treat acute colds, cough and abnormal mucous asthma caused by a cold, or "Nai-Zi-Lai" in the Uygur language. Studies have confirmed the use of HCZP to treat cough variant asthma (CVA) and other respiratory diseases. However, the pharmacological mechanisms of HCZP remain unrevealed.

AIM OF THE STUDY

To investigate the anti-tussive and anti-asthmatic effects and the possible pharmacological mechanisms of HCZP in the treatment of CVA.

MATERIALS AND METHODS

A guinea pig CVA animal model was established by intraperitoneal injection of ovalbumin (OVA) combined with intraperitoneal injection of aluminium hydroxide adjuvant and atomized OVA. Meanwhile, guinea pigs with CVA received oral HCZP (at dosages of 0.571, 0.285 and 0.143 g/kg bodyweight). The number of coughs induced by aerosol capsaicin was recorded, and the airway hyperresponsiveness (AHR) of CVA guinea pigs was detected with the FinePointe series RC system. H&E staining of lung tissues was performed to observe pathological changes. ELISA was used to detect inflammatory cytokines. qRT-PCR and western blotting analyses were used to detect the expression of Th1-specific transcription factor (T-bet), Th2-specific transcription factor (GATA3), and Toll-like receptor 4 (TLR4) signal transduction elements. These methods were performed to assess the protective effects and the potential mechanisms of HCZP on CVA.

RESULTS

Great changes were found in the CVA guinea pig model after HCZP treatment. The number of coughs induced by capsaicin in guinea pigs decreased, the body weights of guinea pigs increased, and inflammation of the eosinophilic airway and AHR were reduced simultaneously. These results indicate that HCZP has a significant protective effect on CVA. A pharmacological study of HCZP showed that the levels of interleukin-4 (IL-4) and IL-5 and tumour necrosis factor-α (TNF-α) in serum decreased. The amount of interferon-γ (IFN-γ) increased, mRNA and protein expression of TLR4 and GATA3 weakened, and mRNA and protein expression of T-bet increased.

CONCLUSIONS

HCZP ameliorated the symptoms of guinea pigs with CVA induced by OVA by regulating the Th1/Th2 imbalance and TLR4 receptors.

Network Pharmacology Strategy to Investigate the Pharmacological Mechanism of HuangQiXiXin Decoction on Cough Variant Asthma and Evidence-Based Medicine Approach Validation

Objective

To investigate the pharmacological mechanism of HuangQiXiXin decoction (HQXXD) on cough variant asthma (CVA) and validate the clinical curative effect.

Methods

The active compounds and target genes of HQXXD were searched using TCMSP. CVA-related target genes were obtained using the GeneCards database. The active target genes of HQXXD were compared with the CVA-related target genes to identify candidate target genes of HQXXD acting on CVA. A medicine-compound-target network was constructed using Cytoscape 3.6.0 software, and a protein-protein interaction (PPI) network was constructed using the STRING database. Gene ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed using RGUI3.6.1 and Cytoscape 3.6.0. We searched the main database for randomized controlled trials of HQXXD for CVA. We assessed the quality of the included studies using the Cochrane Reviewers' Handbook. A meta-analysis of the clinical curative effect of HQXXD for CVA was conducted using the Cochrane Collaboration's RevMan 5.3 software.

Results

We screened out 48 active compounds and 217 active target genes of HQXXD from TCMSP. The 217 active target genes of HQXXD were compared with the 1481 CVA-related target genes, and 132 candidate target genes for HQXXD acting on CVA were identified. The medicine-compound-target network and PPI network were constructed, and the key compounds and key targets were selected. GO function enrichment and KEGG pathway enrichment analysis were performed. Meta-analysis showed that the total effective rate of the clinical curative effect was significantly higher in the experimental group than the control group.

Conclusion

The pharmacological mechanism of HQXXD acting on CVA has been further determined, and the clinical curative effect of HQXXD on CVA is remarkable.

lncRNA PCGEM1 strengthens anti-inflammatory and lung protective effects of montelukast sodium in children with cough-variant asthma

Montelukast sodium is an effective and well-tolerated anti-asthmatic drug. Long non-coding RNAs (lncRNAs) are involved in the treatment of asthma. Therefore, this study aimed to investigate the effect of montelukast sodium on children with cough-variant asthma (CVA) and the role of lncRNA prostate cancer gene expression marker 1 (PCGEM1) in drug efficacy. The efficacy of montelukast sodium was evaluated by assessing the release of inflammatory factors and pulmonary function in CVA children after a 3-month treatment. An ovalbumin (OVA)-sensitized mouse model was developed to simulate asthmatic conditions. PCGEM1 expression in clinical peripheral blood samples and lung tissues of asthmatic mice was determined. Asthmatic mice experienced nasal inhalation of PCGEM1 overexpression with simultaneous montelukast sodium to investigate the roles of PCGEM1 in asthma treatment. The NF-κB axis after PCGEM1 overexpression was detected to explore the underling mechanisms. Consequently, montelukast sodium contributed to reduced levels of pro-inflammatory factors and improved pulmonary function in CVA children. PCGEM1 was poorly expressed in OVA-sensitized asthmatic mice and highly expressed in CVA children with response to the treatment. PCGEM1 overexpression enhanced the anti-inflammatory effects and promoted effects on pulmonary function of montelukast sodium in CVA children and OVA-sensitized asthmatic mice. Furthermore, PCGEM1 inhibited the activation of the NF-κB axis. This study demonstrated the anti-inflammatory and lung-protective effects of montelukast sodium on CVA, which was strengthened by overexpression of PCGEM1. Findings in this study highlighted a potential anti-asthmatic target of montelukast sodium.

An inflammatory stimulus sensitizes TRPA1 channel to increase cytokine release in human lung fibroblasts

External stimuli such as cigarette smoke and house dust mite are often involved in the development and exacerbation of asthma. These risk factors could activate or sensitize transient receptor potential channel ankyrin 1 (TRPA1), which are primarily expressed in neuronal structures but also in non-neuronal cells such as fibroblasts. However, the role of non-neuronal TRPA1 in the pathophysiology of airway diseases including asthma remains unclear. We investigated TRPA1 expression on human fibroblast cells and whether inflammatory mediators could modulate its function. This study utilized human lung fibroblast cell lines, Medical Research Council cell strain 5 (MRC-5) and HF19 cells frequently used on experimental studies regarding allergic and respiratory disorders. The human lung fibroblasts were stimulated with house dust mite (Der p1) or tumor necrosis factor alpha (TNF-α) for 24 h, and we quantified TRPA1 mRNA and protein by qRT-PCR and western blot analysis, respectively. TRPA1 mRNA expressions were upregulated after TNF-α treatment. Calcium imaging analysis revealed that TNF-α treatment apparently sensitized TRPA1-mediated calcium influx by TRPA1 agonist allyl isothiocyanate (AITC) and the selective TRPA1 channel blocker HC-030031 effectively reduced the calcium response. Lastly, TRPA1 activation was not only involved in increased IL-8 cytokine release, but also in upregulating gene expression of matrix metalloprotease 9 (MMP9) in the human lung fibroblasts treated with TNF-α Together, these results indicate that presence of inflammatory mediators such as TNF-α could upregulate the non-neuronal expression of TRPA1 on fibroblasts which may aggravate further the release of inflammatory cytokines observed in human airway diseases.

Identification of quality control markers in Suhuang antitussive capsule based on HPLC-PDA fingerprint and anti-inflammatory screening

Suhuang antitussive capsule (SH), one of traditional Chinese patent medicines, has been widely used for treating cough variant asthma and postinfectious cough in clinic. The objective of this work is to identify the characteristic and active ingredients as the quality control markers for SH based on high performance liquid chromatography with photodiode array detector (HPLC-PDA) fingerprint and screening of anti-inflammatory components. Similarity analysis (SA), hierarchical clustering analysis (HCA) and principal component analysis (PCA) were used to evaluate 16 different batches of SH. 13 compounds accounting for 36% of the total components in the fingerprint were identified and semi-quantitatively analyzed, which anti-inflammatory activity was tested with the in vitro assay. The results showed that the established chemical fingerprint could clearly distinguish different batches of SH by SA, HCA, and PCA analysis. Furthermore, four known compounds (chlorogenic acid, schisandrin, angeloylgomisin H and praeruptorin A) were screened out to be the most discriminant variables, which could be applied to quality control of SH by quantitative analysis. The semi-quantitative results showed that six compounds were major components, i.e. arctiin (10.28 ± 3.18 mg/g), ephedrine (9.26 ± 1.58 mg/g), schisandrin (3.09 ± 0.83 mg/g), pseudoephedrine (2.34 ± 1.04 mg/g), schisandrin B (1.48 ± 0.16 mg/g), and 1-caffeoylquinic acid (1.36 ± 0.42 mg/g). The anti-inflammatory results showed that SH extract, praeruptorin A, schisandrin, arctigenin and pseudoephedrine could significantly inhibit inflammatory mediator NO production in LPS-stimulated RAW264.7 macrophages. These findings indicated that praeruptorin A, schisandrin, arctiin and pseudoephedrine could be proposed as the quality control markers for SH.

Role and Impact of Chronic Cough in Individuals with Asthma From the General Population

BACKGROUND

Cough is a well-recognized symptom in asthma, but the role and impact of chronic cough in individuals with asthma has not been described in the general population.

OBJECTIVE

We hypothesized that among individuals with asthma, those with chronic cough versus those without have a more severe disease phenotype.

METHODS

We identified individuals with asthma and chronic cough among 14,740 adults from the Copenhagen General Population Study, and investigated respiratory symptoms, health care utilizations, lung function, and biomarkers in blood.

RESULTS

A total of 855 (6%) individuals suffered from asthma, and 70 (8%) had chronic cough. Individuals with asthma and chronic cough had a Leicester Cough Questionnaire median total score of 16.8 (25th and 75th percentiles, 14.8-18.9), corresponding to 5.4 (4.6-6.0) for the physical domain, 5.7 (4.6-6.4) for the psychological domain, and 6.0 (5.3-6.8) for the social domain. Among individuals with asthma, those with chronic cough versus those without reported more often wheezing (70% vs 54%), dyspnea (74% vs 49%), night-time dyspnea (27% vs 11%), sputum production (59% vs 14%), chest pain/tightness (14% vs 4%), acute bronchitis/pneumonia episodes, and general practitioner visits. Furthermore, these individuals had more often FEV₁ predicted value of less than 60% (14% vs 7%) and higher levels of neutrophils, leukocytes, and fibrinogen in blood, but there were no differences with regard to levels of high-sensitive C-reactive protein, eosinophils, and IgE in blood.

CONCLUSIONS

Chronic cough in individuals with asthma is associated with a more severe disease phenotype in terms of worse respiratory symptoms, greater health care utilizations, lower lung function, and higher levels of systemic inflammatory biomarkers in blood.

A retrospective study of clinical features of cough variant asthma in Chinese adults

Background

Clinical features of cough variant asthma (CVA) in Chinese adults are largely uncertain.

Methods

A total of 303 patients newly diagnosed as uncontrolled asthma (symptom control and future risk of adverse outcomes), including 175 CVA and 128 classic asthma (CA), were enrolled in this retrospective survey. Clinical features including basic characteristics, pulmonary function, airway hyperresponsiveness (AHR) and cell counts of induced sputum, were compared retrospectively. All patients were classified into four inflammatory subtypes based on the counts of induced sputum eosinophils and neutrophils as eosinophilic (E), neutrophilic (N), mixed granulocytic (M), and paucigranulocytic (P) subtypes. Inflammatory subtype distribution was also compared.

Results

Compared with CA patients, CVA patients were younger (P = 0.009), had a higher prevalence of female patients (P = 0.001), higher parameter values of baseline pulmonary function (P ≤ 0.01 for all), shorter duration of disease (P = 0.002), lower AHR (P = 0.001) and lower sputum eosinophil% (P = 0.009). There was a difference in the AHR distribution as the percentage of moderate and severe AHR in CVA was significantly lower than in CA (41.72% VS 64.70%, P = 0.001). The inflammatory subtype distribution was different as the proportion of E and M subtypes in CVA was lower than in CA (56.0% vs 67.19%, P = 0.049). The proportion of subtype P was the lowest and subtype M was the highest in both CVA and CA patients. There was a similar negative correlation of sputum eosinophil% with AHR in CVA and CA (r = − 0.337, P < 0.0001 and r = − 0.27, P = 0.026, respectively), and a positive correlation between sputum eosinophil% and improvement rate of FEV₁ after inhalation of bronchodilator (ΔFEV₁%) (r = 0.33, P = 0.01).

Conclusions

CVA patients showed a better pulmonary function and lower airway inflammation in contrast to CA patients, which may participate in the pathogenesis of chronic cough in CVA.

A breath sound analysis in children with cough variant asthma

BACKGROUND

Cough variant asthma (CVA) is characterized by a chronic cough and bronchial hyperresponsiveness without confirmation of wheezing. Using a breath sound analyzer, we evaluate the characteristics of breath sound in children with CVA.

METHODS

Nine children with CVA (median age, 7.0 years) participated. The existence of breath sounds was confirmed by sound spectrogram. Breath sound parameters, the frequency limiting 50% and 99% of the power spectrum (F₅₀ and F₉₉), the roll-off from 600 to 1200 Hz (Slope) and spectrum curve indices, the ratio of the third and fourth area to the total area of the power spectrum (P₃/P_T and P₄/P_T) and the ratio of power and frequency at 50% and 75% of the highest frequency of the power spectrum (RPF₇₅ and RPF₅₀) were calculated before and after β₂ agonist inhalation. A spirogram and/or forced oscillation technique were performed in all subjects.

RESULTS

On a sound spectrogram, wheezing was confirmed in seven of nine patients. All wheezing on the image was polyphonic, and they almost disappeared after β₂ agonist inhalation. An analysis of the breath sound spectrum showed that P_T, P₃/P_T, P₄/P_T, RPF₅₀ and RPF₇₅ were significantly increased after β₂ agonist inhalation.

CONCLUSIONS

Children with CVA showed a high rate of inaudible wheezing that disappeared after β₂ agonist inhalation. Changes in the spectrum curve indices also indicated the bronchial reversibility. These results may suggest the characteristics of CVA in children.

Pattern of Response to Bronchial Challenge with Histamine in Patients with Non-Atopic Cough-Variant and Classic Asthma

Background: The aim of this study was to establish whether non-atopic patients with cough variant asthma (CVA) have different pattern of response to direct bronchoconstrictors than non-atopic patients with classic asthma (CA). Method: A total of 170 patients of both sexes with stable CVA and CA were screened for the study and 153 were included. Patients with proven atopy were not included and 17 patients with worsening of their condition or with verified bronchial obstruction during screening were excluded. All included patients performed spirometry and underwent a bronchial challenge with histamine according to long-standing protocol in our laboratory. Results: Significantly higher frequency of bronchial hyper-responsiveness (BHR) was found in patients with CA than in patients with CVA (63.9% vs. 44.9%, respectively; p < 0.05). Sensitivity was significantly lower in patients with CVA (p < 0.05), while no significant difference was found in maximal response and responsiveness. Only patients with positive challenge tests were included in the analysis. Conclusion: Adult non-atopic patients with CVA and CA have a pattern of response to non-specific bronchial stimuli similar to atopic patients with same conditions, with the exception of similar maximal response, which may reflect the efficacy of previous treatment. We believe that further studies are needed to clarify the mechanisms involved in airway response to non-specific stimuli in CVA and CA, especially in non-atopic patients. Further studies should also clarify whether this response pattern has any implications on clinical presentation or on treatment options.

WeChat Public Account Use Improves Clinical Control of Cough-Variant Asthma: A Randomized Controlled Trial

Background

WeChat is a convenient and popular social medium, and it seems to be an appropriate platform for education and management of patients. This study sought to identify usefulness in clinical control of cough-variant asthma (CVA).

Material/Methods

A randomized controlled trial was conducted among 80 CVA patients. After being assigned to either the traditional group (TG) or the WeChat group (WG), they received the same inhalation therapy, but patients in WG received additional education and instruction via our public account on the WeChat application. Questionnaires on asthma and chronic cough, data on pulmonary function, blood-related items, follow-up adherence, and Emergency Department (ED) visits were collected at the initial visit and at 3 months.

Results

A total of 67 participants completed the trial for analysis. FEV₁/predicted and FEV₁/FVC were significantly increased in WG (p<0.001; p=0.012) after 3 months. PD₂₀-FEV₁ was increased in both groups compared with baseline, but more pronounced in WG (p=0.004). ACQ-7 scores were improved in both groups (p=0.024; p<0.001). Participants allocated to WG experienced a greater improvement in AQLQ and LCQ scores, and between-group differences were significant at 3 months (p=0.040; p=0.001). Furthermore, we observed decreases in blood eosinophil count and FeNO in WG (p=0.048; p=0.014), and WG presented better follow-up compliance (p=0.034).

Conclusions

Using WeChat as part of treatment and management of CVA can help patients learn about their disease and medications, as well as improve disease control and therapy outcomes.

Future treatment for asthma

The landscape of asthma has considerably changed after 40 years of inhaled corticosteroid development and nearly 20 years since the first monoclonal antibodies (mAbs) were approved. New members of pharmacological families and more effective drug-delivery devices have been designed but the proportion of uncontrolled patients, unfortunately, remains stable. The most promising treatments now rely on targeted therapies that encourage the improvement of the characterisation of our patients. These clinical (phenotype) or new biological (endotype) tools lead to palpable personalised medicine. This review examines not only the future of mAbs and other new ways of treating asthma but also describes futuristic views based on the paradigm shifts that are ready to occur.

Clinical features in patients of cough variant asthma with normal and high level of exhaled fractional nitric oxide

OBJECTIVE

Cough variant asthma (CVA) is a subtype of asthma that is characterized by a chronic cough. The clinical characteristics and pulmonary function in patients with CVA who had normal and high exhaled fractional nitric oxide (FeNO) levels were compared.

METHODS

The clinical history and pulmonary function data from 99 patients with newly diagnosed CVA were collected.

RESULT

Newly diagnosed subjects with CVA were divided into a high FeNO group (FeNO value over or equal to 25 ppb, n = 52) and a normal FeNO group (FeNO lower than 25 ppb, n = 47). There were more patients with coexistent allergic rhinitis or with family histories of allergic diseases in the high FeNO group. More patients in the high FeNO group reported that their chronic cough was triggered by allergen exposure. In the high FeNO group, the patients were younger than in the normal FeNO group. It was shown that baseline lung function tests were normal in all subjects, apart from a reduced midexpiratory flow rate (FEF25-75). There was a significant decrease in FEF25-75 in the high FeNO group compared with the normal FeNO group. No difference was found in the PD20 or the maximal FEV1 drop between the two groups. The multi-factor logistic regression analysis showed that concomitant with allergic rhinitis was the high risk factor of a high FeNO in these subjects with CVA (OR = 5.03, 95% CI, 1.88-13.49).

CONCLUSION

CVA patients showed heterogeneity according to FeNO level. Patients with high FeNO level are more likely to experience symptoms associated with allergies.

[Role of serum neutrophil elastase determination in the diagnosis of acute exacerbation of asthma in preschool children]

OBJECTIVE

To study the role of serum neutrophil elastase (NE) level in acute exacerbation of asthma in preschool children.

METHODS

A total of 85 preschool children who were diagnosed with asthma between January 2008 and January 2010 were classified into acute exacerbation group (n=44) and non-acute exacerbation group (n=41). Thirty-five children who received physical examination served as the control group. The enzyme-linked immunosorbent assay was used to determine the serum levels of NE and interleukin-8 (IL-8). The receiver operating characteristic (ROC) curve was used for NE evaluation.

RESULTS

Both the acute and non-acute exacerbation groups had higher serum levels of NE and IL-8 than the control group, and the acute exacerbation group had significantly higher serum levels of NE and IL-8 than the non-acute exacerbation group (P<0.05). The serum level of NE was positively correlated with that of IL-8 (r=0.48, P<0.05). With serum NE level >27.73 μg/L as the cut-off value for diagnosing acute exacerbation of asthma, the sensitivity was 65.9%, the specificity was 95.1%, and the area under the ROC curve was 0.87 (P<0.01).

CONCLUSIONS

The determination of serum NE level in preschool children with asthma helps to diagnose the acute exacerbation of asthma.

Pathophysiological characteristics of asthma in the elderly: a comprehensive study

BACKGROUND

Comprehensive studies of the pathophysiologic characteristics of elderly asthma, including predominant site of disease, airway inflammation profiles, and airway hyperresponsiveness, are scarce despite their clinical importance.

OBJECTIVE

To clarify the pathophysiologic characteristics of elderly patients with asthma.

METHODS

Patients older than 65 years (elderly; n = 45) vs those no older than 65 years (nonelderly; n = 67) were retrospectively analyzed by spirometry, computed tomographic indices of large airway wall thickness and small airway involvement (air trapping), impulse oscillation measurements, exhaled nitric oxide levels, blood and induced sputum cell differentials, methacholine airway responsiveness, and total and specific serum IgE levels.

RESULTS

Elderly patients with asthma had significantly lower values for forced expiration volume in 1 second, mid-forced expiratory flow (percentage predicted), and ratio of forced expiration volume in 1 second to forced vital capacity than nonelderly patients with asthma (median 81.2% vs 88.8%, P = .02; 50.9% vs 78.6%, P = .03; 0.72 vs 0.78, P = .001, respectively). In computed tomographic measurements, elderly patients with asthma had significantly greater airway wall thickening and air trapping than nonelderly patients. Impulse oscillation measurements indicated that elderly patients with asthma showed significantly greater resistance at 5 Hz (used as an index of total airway resistance), greater decrease in resistance from 5 to 20 Hz, a higher ratio of decrease in resistance from 5 to 20 Hz to resistance at 5 Hz, higher integrated area between 5 Hz and frequency of resonance, greater frequency of resonance, and lower reactance at a frequency of 5 Hz (potential markers of small airway disease) than nonelderly patients. There were no significant differences in blood or sputum cell differentials, exhaled nitric oxide, or methacholine airway responsiveness between the 2 groups. Total serum IgE levels and positive rates of specific IgE antibodies against several allergens were significantly lower in elderly than in nonelderly patients with asthma.

CONCLUSION

Based on spirometric, computed tomographic, and impulse oscillation analyses, elderly patients with asthma have greater involvement of small and large airways than nonelderly patients with asthma.

Cough in asthma is due to eosinophilic airway inflammation: a pro/con debate

Multiple prospective studies have demonstrated that asthma is among the most common etiologies of chronic cough, along with upper-airway cough syndrome (formerly known as postnasal drip syndrome) and gastroesophageal reflux disease. More recently, the entity of nonasthmatic eosinophilic bronchitis has been appreciated as a significant cause of chronic cough worldwide. Chronic cough associated with both of these conditions typically responds well to therapy with systemic or inhaled corticosteroids, thus leading to a general assumption that the suppression of eosinophilic airway inflammation explains the improvement in cough. However, some recent studies challenge a causal relationship between eosinophilic airway inflammation and cough in asthmatics. The 4th American Cough Conference, held in New York in June 2013, provided an ideal forum for discussion and debate of this issue between two internationally recognized experts in the field of asthma and chronic cough.

Chronic cough and obstructive sleep apnoea in a sleep laboratory-based pulmonary practice

BACKGROUND

Obstructive sleep apnoea (OSA) has recently been identified as a possible aetiology for chronic cough. The aim of this study was to compare the incidence of chronic cough between patients with and without OSA and the impact of continuous positive airway pressure (CPAP) treatment in resolving chronic cough.

METHODS

Patients referred to the sleep laboratory from January 2012 to June 2012 were retrospectively enrolled. Clinical data, treatment course and resolution of chronic cough were analysed. Specifically, gastro-oesophageal reflux (GERD), upper airway cough syndrome, asthma, apnoea-hypopnoea index and the impact of CPAP treatment on chronic cough were assessed.

RESULTS

A total of 131 patients were reviewed. The incidence of chronic cough in the OSA group was significantly higher than the non-OSA group (39/99 (39.4%) vs. 4/32 (12.5%), p = 0.005). Both GERD and apnoea-hypopnoea index were significantly associated with chronic cough in univariate analysis. After multivariate logistic regression, GERD was the only independent factor for chronic cough. Moreover, the resolution of chronic cough was more significant in the OSA patients with CPAP treatment compared with those not receiving CPAP treatment (12/18 (66.7%) vs. 2/21 (9.5%), p = 0.010).

CONCLUSION

The incidence of chronic cough was significantly higher in the OSA patients. In addition, CPAP treatment significantly improved chronic cough. Therefore, OSA may be a contributory factor to chronic cough.

Cough, asthma, and cysteinyl-leukotrienes

Asthma is a chronic inflammatory disease of the lower airways, involving various cells such as eosinophils, and cytokines and mediators. Cyteinyl-leukotrienes (cys-LTs) are one of the chemical mediators that play major pathophysiological roles in asthma. They are produced by eosinophils and mast cells, and induce bronchoconstriction, mucous hypersecretion, microvascular leakage, eosinophil chemotaxis and airway remodeling. Anti-leukotrienes, including leukotriene receptor antagonists (LTRAs) which block cysLT1 receptors, exert both bronchodilatory and anti-inflammatory effects and are utilized as second- to third-line controller medication of persistent asthma. Cough is a major symptom of asthma, and cough variant asthma (CVA) is an asthma phenotype that solely presents with coughing. Sputum levels of cys-LTs are increased in patients with CVA. Antitussive effects of monotherapy with LTRAs in patients with CVA have been reported. We have recently demonstrated that 4 weeks' treatment with an LTRA montelukast exerted anti-inflammatory effect as proved by a decrease of sputum eosinophils, in addition to attenuation of cough VAS and capsaicin cough sensitivity, as reported previously. Spirometry, airway responsiveness, and impulse oscillation indices (respiratory resistance and reactance) were unchanged. These results suggested that the antitussive effect of montelukast in CVA might be attributable to its anti-inflammatory ability rather than bronchodilation. The treatment did not affect sputum levels of mediators (cys-LTs, LTB4, PGD2, PGE2, PGF2α, and TXB2). Since inhaled corticosteroid does not seem to affect cough sensitivity while attenuating cough in patients with CVA, LTRAs may involve different mechanism(s) from that of corticosteroid. LTRAs must theoretically be effective against cough of asthmatic subjects through its "anti-asthma" effects, while evidence supporting direct antitussive effects of cys-LTs on "cough receptors" is scarce. An important clinical question is that whether LTRAs involve non-specific antitussive effects. While a definite answer is not available yet, this possibility seems unlikely at the moment, although some secondary anti-inflammatory properties have been reported for montelukast. This issue needs to be clarified by future research to avoid overuse of this expensive class of medication.

Endobronchial biopsy: a guide for asthma therapy selection in the era of bronchial thermoplasty

OBJECTIVE

Bronchial thermoplasty (BT) reduces airway smooth muscle in patients with severe asthma. We developed a novel standardized histologic grading system assessing inflammation and structural remodeling on endobronchial biopsy (EBBx) in severe persistent asthma and evaluated airway structure before and after BT. In addition, we correlated invasive and non-invasive inflammatory markers in severe persistent asthma.

METHODS

Thirty-three patients with severe persistent asthma underwent bronchoscopy, including bronchoalveolar lavage (BAL) and diagnostic EBBx. The control group (N = 41) underwent EBBx for other clinical indications. Biopsies were graded for airway inflammation and epithelial and submucosal structural features. We also evaluated airway histology in three patients before and after BT.

RESULTS

Compared to the control group, patients with severe persistent asthma more often had intraepithelial eosinophils and lymphocytes (67% vs. 17% and 61% vs. 27%; p < .001 and p = .005, respectively) and prominent smooth muscle and goblet cell hyperplasia (88% vs. 29% and 47% vs. 22%, p < .001 and p = .004, respectively). Other features including epithelial denudation and basement membrane thickening were not significantly different. Following BT, airway smooth muscle was no longer prominent due to partial replacement by fibrosis. Increased submucosal eosinophilic inflammation and BAL eosinophilia correlated with exhaled nitric oxide (eNO, p = .05 for both).

CONCLUSIONS

We developed a clinically applicable standardized histologic grading system which identified structural but not inflammatory changes before and after BT in severe persistent asthmatics. Additionally, we demonstrated that eNO is representative of submucosal eosinophilia in this population. This semi-quantitative assessment will be useful for practicing pathologists assessing EBBx from severe persistent asthma patients for diagnostic and clinical research purposes.

Inhaled corticosteroids for subacute and chronic cough in adults

BACKGROUND

Persistent cough is a common clinical problem. Despite thorough investigation and empirical management, a considerable proportion of those people with subacute and chronic cough have unexplained cough, for which treatment options are limited. While current guidelines recommend inhaled corticosteroids (ICS), the research evidence for this intervention is conflicting.

OBJECTIVES

To assess the effects of ICS for subacute and chronic cough in adults.

SEARCH METHODS

We searched the Cochrane Airways Group Register of Trials, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and ClinicalTrials.gov in December 2012 and conducted handsearches.

SELECTION CRITERIA

Two authors independently assessed all potentially relevant trials. All published and unpublished randomised comparisons of ICS versus placebo in adults with subacute or chronic cough were included. Participants with known chronic respiratory disease and asthma were excluded. Studies of cough-variant asthma and eosinophilic bronchitis were eligible.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data pertaining to pre-defined outcomes. The primary outcome was the proportion of participants with clinical cure or significant improvement (over 70% reduction in cough severity measure) at follow up (clinical success). The secondary outcomes included proportion of participants with clinical cure or over 50% reduction in cough severity measure at follow up, mean change in cough severity measures, complications of cough, biomarkers of inflammation and adverse effects. We requested additional data from study authors.

MAIN RESULTS

Eight primary studies, including 570 participants, were included. The overall methodological quality of studies was good. Significant clinical heterogeneity resulting from differences in participants and interventions, as well as variation in outcome measures, limited the validity of comparisons between studies for most outcomes. Data for the primary outcome of clinical cure or significant (> 70%) improvement were available for only three studies, which were too heterogeneous to pool. Similarly, heterogeneity in study characteristics limited the validity of meta-analysis for the secondary outcomes of proportion of participants with clinical cure or over 50% reduction in cough severity measure and clinical cure. One parallel group trial of predominantly chronic cough with 'cough-variant asthma' identified a significant treatment effect and contributed to the majority of statistical heterogeneity for these outcomes. While ICS treatment resulted in a mean decrease in cough score of 0.34 standard deviations (SMD -0.34; 95% CI -0.56 to -0.13; 346 participants), the quality of evidence was low. Heterogeneity also prevented meta-analysis for the outcome of mean change in visual analogue scale score. Meta-analysis was not possible for the outcomes of pulmonary function, complications of cough or biomarkers of inflammation due to insufficient data. There was moderate quality evidence that treatment with ICS did not significantly increase the odds of experiencing an adverse event (OR 1.67; 95% CI 0.92 to 3.04).

AUTHORS' CONCLUSIONS

The studies were highly heterogeneous and results were inconsistent. Heterogeneity in study design needs to be addressed in future research in order to test the efficacy of this intervention. International cough guidelines recommend that a trial of ICS should only be considered in patients after thorough evaluation including chest X-ray and consideration of spirometry and other appropriate investigations.

Inflammatory mediators in induced sputum and airway hyperresponsiveness in cough variant asthma during long-term inhaled corticosteroid treatment

Objective. This study aimed to investigate improvements in inflammatory mediator levels in induced sputum and airway hyperresponsiveness (AHR) in cough variant asthma (CVA) during long-term inhaled corticosteroid (ICS) treatment. Patients and Methods. Patients with CVA (N = 35) and classic asthma (N = 26) and healthy subjects (N = 24) were recruited into this study. All patients were treated with budesonide (400 μg/day). Measurement of inflammatory mediators in induced sputum and PD20-FEV₁ (the accumulated provocative dose resulting in a 20% decrease in FEV₁) in histamine-challenged subjects was performed every three months after the start of medication. Interleukin- (IL-) 5 and IL-10 were assayed by ELISA, and the percentage of eosinophils was detected with Giemsa stain. Trends during the follow-up period were analyzed using a general linear model. Results. Inflammatory mediator levels in induced sputum and PD20-FEV₁ in patients with CVA and classic asthma differed from those in the control group, although no differences were found in the two asthmatic groups. PD20-FEV₁ significantly increased in CVA patients after ICS treatment for 3 months, while classic asthma patients exhibited a delayed change in AHR. After ICS treatment, levels of IL-5 and IL-10 as well as the percentage of eosinophils in the CVA group were altered at 3 months and 6 months, respectively. Accordingly, the level of inflammatory mediators in classic asthma changed more slowly. Conclusion. CVA has a greater improvement in airway inflammation and airway hyperresponsiveness (AHR) than classic asthma with respect to inhaled corticosteroid (ICS). Short-term ICS considerably reduces AHR although longer treatment is required for complete control of airway inflammation.

Cough in asthma

Asthma is one of the most common causes of chronic cough, and cough may be the sole or predominant symptom of asthma. The mechanisms of cough in asthma are complex and presumbably multi-factorial. In particular, the pathophysiologic basis of cough variant versus classic asthma is poorly understood. Recent research utilizing various inhalation challenge tests suggests that preservation of the bronchodilating and bronchoprotective effects of deep inspirations is a distinguishing feature of cough variant asthma. This review outlines the tussive agents used in cough research (including tussive and direct, indirect and combined bronchoconstrictive stimuli), their mechanisms of action, the receptors involved in eliciting cough, and characteristic responses in classic asthma and cough variant asthma.

Cough and Asthma

Cough is the most common complaint for which patients seek medical attention. Cough variant asthma (CVA) is a form of asthma, which presents solely with cough. CVA is one of the most common causes of chronic cough. More importantly, 30 to 40% of adult patients with CVA, unless adequately treated, may progress to classic asthma. CVA shares a number of pathophysiological features with classic asthma such as atopy, airway hyper-responsiveness, eosinophilic airway inflammation and various features of airway remodeling. Inhaled corticosteroids remain the most important form of treatment of CVA as they improve cough and reduce the risk of progression to classic asthma most likely through their prevention of airway remodeling and chronic airflow obstruction.

Structural changes in the airways: cause or effect of chronic cough?

Patients with a chronic cough have asthma or "asthma-related" diagnoses such as cough variant asthma or non-asthmatic eosinophilic bronchitis usually responsive to inhaled corticosteroid therapy, or non-asthma-related diagnoses including "idiopathic" or "unexplained" cases. Both of these conditions involve airway inflammation. More recently, structural changes or remodeling of the lower airways, which have been considered characteristic of classic asthma with wheezing, have also been demonstrated in patients with chronic cough, irrespective of its cause. In this article, the presence, pathogenesis, and possible consequences of such structural changes in patients with chronic cough are reviewed. Although whether chronic cough leads to structural changes or structural changes is a cause of chronic cough is difficult to determine, the concomitance of both mechanisms may lead to a positive feedback mechanism or a vicious cycle of cough persistence.