Addressing corticosteroid insensitivity in adults with asthma

Research on the Mechanism and Application of Acupuncture Therapy for Asthma: A Review

Asthma is a high-risk disease based on airway hyperresponsiveness (AHR). In this review, we found that there are many studies on clinical therapy for asthma that focus on the efficacy of acupuncture therapy and its mechanisms, including the functional connectivity of different brain regions, with the aid of functional magnetic resonance imaging (fMRI), immune responses/cell recognition (innate lymphoid cells and balance of Th1/Th2 and Treg/Th17), intracellular mechanism (autophagy, endoplasmic reticulum stress, and epigenetic alteration), and ligand-receptor/chemical signaling pathway (neurotransmitter, hormone, and small molecules). In this review, we summarized the clinical and experimental evidence for the mechanisms of acupuncture therapy in asthma to offer insights into drug discovery and clinical therapy. Given the paucity of clinical studies on the mechanisms of acupuncture in the treatment of asthma, this review notably included studies based on animal models to investigate the mechanisms of acupuncture in the treatment of asthma.

Single-cell transcriptomics delineates the immune cell landscape in equine lower airways and reveals upregulation of FKBP5 in horses with asthma

Equine asthma (EA) is a heterogenous, complex disease, with a significant negative impact on horse welfare and performance. EA and human asthma share fundamental similarities, making EA a useful model for studying the disease. One relevant sample type for investigating chronic lung inflammation is bronchoalveolar lavage fluid (BALF), which provides a snapshot of the immune cells present in the alveolar space. To investigate the immune cell landscape of the respiratory tract in horses with mild-to-moderate equine asthma (mEA) and healthy controls, single-cell RNA sequencing was conducted on equine BALF cells. We characterized the major immune cell populations present in equine BALF, as well as subtypes thereof. Interestingly, the most significantly upregulated gene discovered in cases of mEA was FKBP5, a chaperone protein involved in regulating the activity of the glucocorticoid receptor.

Asthma and Tobacco Smoking

Asthma is a prevalent chronic pulmonary condition with significant morbidity and mortality. Tobacco smoking is implicated in asthma pathophysiology, diagnosis, prognosis and treatment. Smokers display increased prevalence and incidence of asthma, but a causal association cannot be claimed using existing evidence. Second-hand smoking and passive exposure to tobacco in utero and early life have also been linked with asthma development. Currently, approximately one-fourth of asthma patients are smokers. Regular smokers with asthma might display accelerated lung function decline and non-reversible airflow limitation, making their distinction from chronic obstructive pulmonary disease patients challenging. Asthma patients who smoke typically have uncontrolled disease, as shown by increased symptoms, more exacerbations and impaired quality of life. On the other hand, smoking cessation improves lung function and asthma severity. Thus, asthma patients and their caregivers should be actively questioned about their smoking status at each medical encounter, and smoking cessation ought to be strongly encouraged both for patients with asthma and their close contacts. Smokers with asthma should be provided with comprehensive smoking cessation interventions on top of other anti-asthma medications.

Suhuang Antitussive Capsule Ameliorates Corticosteroid Insensitivity in Cough Variant Asthma Guinea Pigs by Inhibiting p38 MAPK Signal Pathway

Methods

The CVA guinea pig model was successfully established by use of ovalbumin (OVA) sensitization and cigarette smoke (CS) exposure. The guinea pigs were divided into 6 groups: a control group, an OVA model group, an OVA + CS model group, a Suhuang treatment group, a BUD treatment group, and a combination (Suhuang and BUD) treatment group. The effects of the treatment were determined by measuring lung function (RI/Cydn) and cough symptoms (coughs number/cough latency) as outcome criteria. The levels of inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were determined by ELISA. Lung tissues were stained by hematoxylin and eosin (H&E). The expressions of GR/total p38 MAPK/p-p38 MAPK were detected by Western blot. The MKP-1 mRNA levels were detected by RT-PCR.

Results

Combination treatment significantly decreased RI/coughs numbers and increased Cydn/cough latency. Significantly, the results indicated that combination treatment decreased injury to pulmonary tissues. Results also revealed that levels of inflammatory cytokines were reduced in all treatment groups but most markedly in the combination treatment group. Moreover, Suhuang treatment significantly ameliorated corticosteroid insensitivity by improving the expression of glucocorticoid receptors (GR). The expressions of total p38 MAPK and p-p38 MAPK in lung tissue were significantly inhibited in the Suhuang and combination treatment groups. The MKP-1 mRNA levels in Suhuang and combination treatment groups were also increased significantly.

Conclusion

Suhuang was effective for reversing corticosteroid insensitivity by regulating the p38 MAPK signal pathway, and combining BUD and Suhuang treatment showed synergistic interactions in CVA guinea pigs. Our findings showed that this combination therapy might be a promising therapeutic agent for CVA and also clarified its underlying mechanism of action, providing a theoretical basis for clinical combination treatment with Suhuang and BUD in CVA patients.

The association of FKBP5 polymorphism with asthma susceptibility in asthmatic patients

OBJECTIVES

Inhaled corticosteroids are the most effective controllers of asthma, although asthmatics vary in their response. FKBP51 is a major component of the glucocorticoid receptor which regulates its responses to corticosteroids. Therefore, the present study aims to identify the role of FKBP5 gene polymorphism in asthma susceptibility and corticosteroid resistance.

METHODS

DNA was extracted from the blood of 68 asthmatic and 40 control subjects. FKBP5 gene fragments were amplified by PCR and sequenced by the Sanger method. The sequencing results were aligned by mapping on the reference sequences of National center of Biotechnology Information (NCBI) and single nucleotide polymorphisms (SNPs) which were checked. Finally, the genotype, allele frequency and odds ratio (OR) were calculated.

RESULTS

The FKBP5 fragment sequencing revealed the presence of rs1360780 and one novel SNP found in 17 samples taken from asthmatic patients as compared to db SNP data in the NCBI database. The FKBP5 variant (rs1360780) indicated that the allele frequency of risk allele T was 41.18% in patients and 20% in control group members p<0.001 and OR=2.8 when compared to a wild C allele frequency of 58.82% in patients and 64% in the control group members. The novel SNP FKBP5 was compared to the SNP database in the NCBI database in which wild T allele was substituted with G. The novel SNP was submitted to the ClinVar Submission Portal at NCBI with accession number: rs1581842283 and confirmed an asthma susceptibility risk factor with allele G frequency of 11.76% in asthmatics and 2.5% in the control group members (OR=5.2, p<0.05), as compared to a wild T allele frequency of 88.24% in asthmatics and 97.5% in the control group members.

CONCLUSIONS

The risk allele T of rs1360780 and the novel SNP rs1581842283 risk allele G predict asthma susceptibility but show no association with corticosteroid resistant.

Challenges in the management of asthma associated with smoking-induced airway diseases

INTRODUCTION

Smoking-induced airway diseases such as chronic bronchitis, emphysema, and small airway dysfunction contribute to the chronic respiratory symptoms experienced by adults with asthma, including those with spirometric chronic obstructive pulmonary disease (COPD), termed asthma-COPD overlap (ACO). Drug treatment of symptomatic smokers with asthma or ACO is uncertain due to their exclusion from most clinical trials.

AREAS COVERED

This review summarizes evidence for the efficacy of small molecule drugs used in the clinic to treat current and former smokers with a diagnostic label of asthma or ACO. Other therapeutic interventions are reviewed, including smoking cessation and biologics.

EXPERT OPINION

Clinical trials and observational studies suggest that smoking cessation and approved drugs used to treat non-smokers with asthma produce clinical benefits in smokers with asthma or ACO, although the overall quality of evidence is low. The efficacy of some treatments for asthma is altered in current smokers, including reduced responsiveness to short-term inhaled corticosteroids and possibly improved responsiveness to leukotriene receptor antagonists. Preliminary findings suggest that low-dose theophylline, statins, and biologics, such as omalizumab, mepolizumab, and dupilumab, may improve clinical outcomes in smokers with asthma or ACO. Improved phenotyping and endotyping of asthma and smoking-induced airway diseases should lead to better targeted therapies.

Treating Pediatric Asthma According Guidelines

Asthma is a common chronic inflammatory disorder of the lower respiratory airways in childhood. The management of asthma exacerbations and the disease control are major concerns for clinical practice. The Global Strategy for Asthma Management and Prevention, published by GINA, updated in 2017, the British Thoracic Society/Scottish Intercollegiate Guideline Network, revised in 2016, the National Institute for Health and Care Excellence asthma guideline consultation, available in 2017, are widely accepted documents, frequently implemented, with conflicting advices, and different conclusion on asthma definition and treatment. An International Consensus on Pediatric Asthma was carried out in 2012 by a Committee with expertise in the field, to critically review differences on current guidelines. In addition, the specific issue of treating severe and difficult asthma has been recently highlighted throughout the International European Respiratory Society/American Thoracic Society guidelines on severe asthma. The aim of this paper is to describe conventional treatments and some new therapeutic approaches to pediatric asthma according to guidelines, highlighting key aspects, and differences on proposed clinical recommendations for asthma management. Age specific therapy are proposed in steps, according to clinical severity and the level of disease control. If control is not achieved within 3 months, stepping-up should be considered; otherwise, if control is achieved after 3 months, stepping down may be considered. The most used drug classes of asthma medications are beta-2 adrenergic agonists, corticosteroids, and leukotriene modifiers. Intramuscolar triamcinolone has been used for severe asthma treatment. Chromones and xanthines have been extensively used in the past, but they have shown limits related to their efficacy and safety profile. Omalizumab, a monoclonal antibody against IgE, is an immunomodulatory biological agent, used as new drug in patients with confirmed IgE-mediated allergic asthma, only for patient's specific range of total IgE level. There are low evidences in the efficacy of metotrexate, as well as macrolide antibiotics in children with asthma. Antifungal agents are also not recommended in asthmatic patients. Non-pharmacological measures that may improve patient's quality of life should also be attempted. We conclude that treatment decisions on childhood asthma management should be critically made, pondering the differences suggested by agreed international consensus documents.

Glucocortiosteroid subsensitivity and asthma severity

PURPOSE OF REVIEW

Glucocorticosteroids (GCSs) remain the cornerstone of therapy for treating the inflammatory component of asthma. Clinical response to GCS is heterogeneous, varying both within asthma 'endotypes', as well as the same individual. Different factors and micro-environment can alter the canonical GCS-induced signalling pathways leading to reduced efficacy, collectively termed as GCS subsensitivity, which includes the entire spectrum of steroid insensitivity and steroid resistance.

RECENT FINDINGS

In the past, steroid subsensitivity has been associated with dysregulated expression of glucocorticoid-receptor isoforms, neutrophilic inflammation and Th17 cytokines, oxidative stress-inducing factors and their downstream effect on histone deacetylase activities and gene expression. The review highlights recent observations, such as GCS-induced dysregulation of key transcription factors involved in host defence, role of airway infections altering expression of critical regulatory elements like the noncoding microRNAs, and the importance of interleukin (IL)-10 in reinstating steroid response in key immune cells. Further, emerging concepts of autoimmunity triggered because of delayed resolution of eosinophilic inflammation (due to GCS subsensitivity) and observed lymphopenia (plausibly a side-effect of continued GCS use) are discussed.

SUMMARY

This review bridges concepts that have been known, and those under current investigation, providing both molecular and clinical insights to aid therapeutic strategies for optimal management of asthmatics with varying degree of steroid subsensitivity and disease severity, with particular emphasis on the PI3 kinase pathways.

Increased serum amyloid A in nasal polyps is associated with systemic corticosteroid insensitivity in patients with chronic rhinosinusitis with nasal polyps: a pilot study

BACKGROUND

Serum amyloid A (SAA) was involved in the pathogenesis of glucocorticoid resistance in lung diseases. However, their association with systemic corticosteroid insensitivity in chronic rhinosinusitis with nasal polyps (CRSwNP) patients remains to be assessed.

METHODS

This study enrolled 32 CRSwNP patients to evaluate the association between SAA expression in NP and corticosteroid insensitivity, and the value of polyp SAA level for predicting the response to oral corticosteroids in CRSwNP patients. All patients were given a course of oral prednisone (30 mg daily for 2 weeks) and subdivided into glucocorticoid(GC)-sensitive and -insensitive subgroup according to the change in polyp size scores. The polyp specimens were obtained before and after corticosteroid treatment. SAA levels in polyp tissues were evaluated by enzyme-linked immunosorbent assay and quantitative reverse transcription polymerase chain reaction. Regression analysis was performed to analyze the association between SAA protein levels and corticosteroid insensitivity.

RESULTS

13/32 (40.62%) CRSwNP patients were insensitive to the oral corticosteroid therapy. SAA mRNA and protein levels were significantly increased in GC-insensitive NP compared to those in GC-sensitive NP. Tissue SAA protein levels were positively correlated with tissue neutrophil numbers. Regression analysis revealed tissue SAA levels were significantly correlated with corticosteroid insensitivity (P < 0.01). ROC curves indicated that the area under the curve was 0.87. When the polyp SAA protein level was 122.2 ng/ml or higher, the sensitivity and specificity were 76.92 and 73.68%, respectively.

CONCLUSIONS

Our findings suggest that increased SAA in NP is associated with reduced response to oral corticosteroids in CRSwNP. SAA levels in NP may have potential value in predicting corticosteroid insensitivity in CRSwNP patients.

Targeted Therapy for Older Patients with Uncontrolled Severe Asthma: Current and Future Prospects

Severe asthma in the elderly places a high burden on affected individuals and society. Emerging therapies target specific phenotypes of the asthma disease spectrum, and can be beneficial for older asthmatics, albeit their response might be altered due to age-related characteristics. Paradoxically, these characteristics are often ground for exclusion from clinical trials. The question thus arises how the senior asthmatic population can successfully enter the era of targeted therapy. Therefore, we highlight characteristics of this population relevant to effective treatment, and review the evidence for targeted therapy in elderly patients. For targeted therapy it is important to account for aging, as this affects the distribution of phenotypes (e.g. late-onset asthma, non-eosinophilic asthma) and may alter biomarkers and drug metabolism. Elderly asthmatics suffer from age-related comorbidities and subsequent polypharmacy. A systematic search into targeted asthma therapy yielded no randomized clinical trials dedicated to older asthmatics. Post hoc analyses of the anti-immunoglobulin E agent omalizumab indicate similar efficacy in both younger and older adults. Conference abstracts on anti-interleukin-5 and anti-interleukin-13 therapy suggest even more pronounced effects of targeted treatments in late-onset disease and in asthmatic patients 65 years or older, but full reports are lacking. For non-eosinophilic asthma in the elderly, there is not yet high-level evidence for targeted therapy, but macrolides may offer a viable option. In conclusion, there is a gap in knowledge regarding the effect of older age on the safety and efficacy of targeted asthma therapy. Further investigations in the elderly are needed, with special emphasis on both late-onset asthma and therapeutics for non-eosinophilic asthma.

Asthma and smoking-induced airway disease without spirometric COPD

Due to the high prevalence rates of cigarette smoking and asthma, current and ex-smokers frequently develop chronic airway disease without spirometric evidence of chronic obstructive pulmonary disease (COPD), either alone or associated with asthma. This review considers the classification, clinical outcomes, inflammatory and imaging variables, phenotypes, and management of current and ex-smokers with airway disease without COPD, focusing on overlaps in those with and without asthma. These individuals have more respiratory symptoms, worse quality of life, increased exacerbation rates, reduced lung function and more comorbidities than never-smokers with asthma or healthy never-smokers. As well as clinical features, airway inflammatory and structural changes in smoking-induced airway disease without COPD overlap with those found in smokers with asthma. Cigarette smoking is associated with worse clinical outcomes in some phenotypes of asthma. Management involves public health measures to control exposure to tobacco smoke, personal advice on smoking cessation and the use of appropriate targeted therapies, although evidence is limited on their effectiveness. Understanding the mechanisms, natural history and management of current and ex-smokers with asthma and smoking-induced airway disease without COPD is a priority for future research.

The management of asthmatic smokers

Asthma is still a major public health problem in most countries; new strategies to better control this disease are necessary. Such strategies must include predisposing factors. One of these factors is smoking and a significant fraction of asthmatics are smokers. However, clinical trials studying new drugs or newer therapeutic regimens for asthma generally exclude smokers. Therefore, there is a lack of specific information about the treatment of asthma in smokers. The asthmatic smoker is a special phenotype with important therapeutic and prognostic clinical implications. Any form of tobacco use, especially cigarette smoking, plays an important role in this disease. Asthmatic smokers are prone to several negative outcomes. Smoking cessation results in an improvement of symptoms and pulmonary functioning. Counselling and first-line medications for smoking cessation (nicotine replacement therapy, bupropion and varenicline) significantly increase quitting rates. The role of electronic cigarettes in this group of patients has only begun to be studied. The treatment of asthmatics that smoke has characteristics that need must be well understood by clinicians, especially the poor response to corticosteroids. This condition is not universal and physicians should always consider its inclusion in the treatment of these patients. The association of inhaled corticosteroids (ICS) plus a long-acting beta2 adrenegic (LABA) by smoking asthmatics results in more pronounced improvement in several asthma outcomes compared with the use of corticosteroid alone. Inhaled corticosteroids in extra-fine particles associated with LABA may be a new perspective of treatment. Also the use of leukotriene antagonists may become another therapeutic alternative. The purpose of this narrative review is to discuss the challenges faced by clinicians to control asthma in smokers and to present methods of coping with smoking treatment and avoiding relapses.