Bronchial thermoplasty and biological therapy as targeted treatments for severe uncontrolled asthma

Novel indocyanine green-loaded photothermal nanoparticles targeting TRPV1 for thermal ablation treatment of severe murine asthma induced by ovalbumin and lipopolysaccharide

To identify a replacement strategy for bronchial thermoplasty (BT) with non-invasive and free-of-severe side effect is urgently needed in the clinic for severe asthma treatment. In this study, PLGA-PEG@ICG@TRPV1 pAb (PIT) photothermal nanoparticles targeting bronchial TRPV1 were designed for photothermal therapy (PTT) against severe murine asthma induced by ovalbumin and lipopolysaccharide. PIT was formulated with a polyethylene glycol (PEG)-grafted poly (lactic-co-glycolic) acid (PLGA) coating as a skeleton structure to encapsulate indocyanine green (ICG) and was conjugated to the polyclonal antibody against transient receptor potential vanilloid 1 (TRPV1 pAb). The results revealed that PIT held good druggability due to its electronegativity and small diameter. PIT demonstrated great photothermal effects both in vivo and in vitro and exhibited good ability to target TRPV1 in vitro because of its selective cell uptake and specific cell toxicity toward TRPV1-overexpressing cells. The PIT treatment effectively reduced asthma symptoms in mice. This is evident from improvements in expiratory airflow limitation, significant decreases in inflammatory cell infiltration in the airways, and increases in goblet cell and columnar epithelial cell proliferation. In conclusion, PIT alleviates severe murine asthma symptoms through a combination of TRPV1 targeting and photothermal effects.

Comparing bronchial thermoplasty with biologicals for severe asthma: Systematic review and network meta-analysis

BACKGROUND

Bronchial thermoplasty (BT) has shown favorable safety and efficacy in several randomized controlled trials (RCTs), but has not been directly compared to biological therapies.

METHODS

Electronic literature searches were performed on PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, to retrieve RCTs of BT or FDA-approved biologicals against controls in patients with severe asthma. Six outcomes were analyzed: Asthma Control Questionnaire (ACQ), Asthma Quality of Life Questionnaire (AQLQ), the number of patients experiencing ≥1 asthma exacerbation, annualized exacerbation rate ratio (AERR), oral corticosteroid dose reduction (OCDR), and morning peak expiratory flow rate (amPEF). Random-effects, Frequentist network meta-analysis (NMA) were performed, and therapies were ranked using P-scores.

RESULTS

Twenty-nine RCTs (15,547 patients) were included. Fewer patients treated with BT experienced ≥1 asthma exacerbation (risk ratio [RR] = 0.66, 95%CI = 0.45-0.98) compared to control. AERR of BT versus control was non-significant, but significant improvements in ACQ score (mean difference [MD] -0.41, 95%CI -0.63 to -0.20), AQLQ score (MD = 0.54, 95%CI = 0.30-0.77), amPEF and OCDR were found. No significant differences between BT and biologics were seen across indirect comparisons of all studies.

CONCLUSIONS

Despite the lack of head-to-head comparative trials, this NMA suggests that BT is non-inferior to biologicals in terms of quality-of-life scores, and represents a promising alternative for patients with severe asthma.

Acrid and Bitter Chinese Herbs in Decoction Effectively Relieve Lung Inflammation and Regulation of TRPV1/TAS2R14 Channels in a Rat Asthmatic Model

Background

Shegan Mahuang decoction (SGMHD) was widely used as a classic prescription of traditional Chinese medicine to treat asthma. However, there is no research on the acrid and bitter Chinese herbs in the SGMHD to treat asthma. This study aimed to investigate the effects of SGMHD and its acrid-bitter Chinese herbs composition on airway inflammation and the expression of TRPV1 and TAS2R14 genes and proteins in asthmatic rats.

Methods

SD (Sprague Dawley) rats of asthma were induced by ovalbumin and aluminum hydroxide, then randomly divided into the Normal group, Model group, SGMHD group, Dexamethasone (Dex) group, Guilongkechuangning (GLKC) group, The Acrid Chinese Herbs group (ACH), and The Bitter Chinese Herbs group (BCH). The rats were given intragastric gavage after 21 days for 4 weeks. The bronchoalveolar lavage fluid (BALF) was collected, and the levels of IL-4, IL-13, nerve factors SP, CGRP, PGE2, and serum of IgE were determined by ELISA. Pathological changes in the lungs were determined by hematoxylin-eosin (HE) staining. The expression of TRPV1 and TAS2R14 in the rat lung group was detected by immunofluorescence (IF). The expression levels of TRPV1 and TAS2R14 were measured using western blotting. The mRNA levels of TRPV1 and TAS2R14 were measured using RT-qPCR.

Results

The levels of serum IgE in treated rats and the cytokines IL-4, IL-13, SP, CGRP, and PGE2 were all decreased. HE-staining showed that significantly reduced inflammatory cell infiltration in lung tissue. IF-staining showed the expression levels except those of the normal group were enhanced. Acrid Chinese herbs inhibited TRPV1, and bitter Chinese herbs activated the gene and protein expression of TAS2R in the lung.

Conclusion

The acrid Chinese herbs regulate TRPV1, and bitter Chinese herbs regulate the gene and protein expression of TAS2R14, through nerve and immune-inflammatory factors, reduced airway inflammation, reduced airway reactivity, promoted airway remodeling, and the combination of acrid-bitter Chinese herbs can enhance the above effects. This will lay a foundation for further in vivo study of specific compounds of acrid-bitter Chinese herbs.

Correlation of Activation Site and Number with the Clinical Response to Bronchial Thermoplasty

Objective

Methods

Results

Conclusion

TH17 cells and corticosteroid insensitivity in severe asthma

Asthma is classically described as having either a type 2 (T2) eosinophilic phenotype or a non-T2 neutrophilic phenotype. T2 asthma usually responds to classical bronchodilation therapy and corticosteroid treatment. Non-T2 neutrophilic asthma is often more severe. Patients with non-T2 asthma or late-onset T2 asthma show poor response to the currently available anti-inflammatory therapies. These therapeutic failures result in increased morbidity and cost associated with asthma and pose a major health care problem. Recent evidence suggests that some non-T2 asthma is associated with elevated T_H17 cell immune responses. T_H17 cells producing Il-17A and IL-17F are involved in the neutrophilic inflammation and airway remodeling processes in severe asthma and have been suggested to contribute to the development of subsets of corticosteroid-insensitive asthma. This review explores the pathologic role of T_H17 cells in corticosteroid insensitivity of severe asthma and potential targets to treat this endotype of asthma.

New Treatments for Asthma

Asthma is a complex, heterogeneous chronic airway disease with high prevalence of uncontrolled disease. New therapies, including biologics, are now available to treat T2 high asthma. Treatment of T2 low asthma remains a challenge. Asthma guidelines need be to updated to incorporate new therapeutics.

Biologics for Severe Asthma: Treatment-Specific Effects Are Important in Choosing a Specific Agent

Patients with uncontrolled severe persistent asthma have greater morbidity, greater use of health care resources, and more impairment in health-related quality of life when compared with their peers with well-controlled disease. Fortunately, since the introduction of biological therapeutics, patients with severe eosinophilic asthma now have beneficial treatment options that they did not have just a few years ago. In addition to anti-IgE therapy for allergic asthma, 3 new biological therapeutics targeting IL-5 and 1 targeting IL-4 and IL-13 signaling have recently been approved by the Food and Drug Administration for the treatment of severe eosinophilic asthma, and approval of more biological therapeutics is on the horizon. These medications decrease the frequency of asthma exacerbations, improve lung function, reduce corticosteroid usage, and improve health-related quality of life. This article reviews the mechanisms of action, specific indications, benefits, and side effects of each of the approved biological therapies for asthma. Furthermore, this article reviews how a clinician could use specific patient characteristics to decide which biologic treatment may be optimal for a given patient.

Bronchial thermoplasty versus mepolizumab: Comparison of outcomes in a severe asthma clinic

BACKGROUND AND OBJECTIVE

BT and interleukin-blocking monoclonal antibodies are both effective therapies for severe asthma, but there have been no direct comparisons between the two treatments. The aim of this study was to compare the efficacy and safety of BT and mepolizumab, in a real-world setting.

METHODS

Patients with severe asthma despite optimized inhaler therapy were drawn from a severe asthma clinic in a tertiary hospital. Every patient commencing therapy with BT or mepolizumab was prospectively included in a national registry. At predetermined assessment points over a 12-month period, assessments were made of ACQ, spirometry, oral corticosteroid requiring exacerbations, reliever medication and maintenance oral corticosteroid use.

RESULTS

A total of 91 patients with severe asthma participated: mean ACQ score 3.5 ± 1.0, FEV₁ 51.4 ± 17.7%, maintenance oral steroids 48.3% and 11.5 ± 10.0 inhalations/day reliever therapy. Forty-seven patients received mepolizumab and 44 received BT. Baseline characteristics were similar except significantly higher blood eosinophil count in the mepolizumab group. At 12 months, there were no differences between treatment outcomes for ACQ (1.9 ± 1.3 mepolizumab vs 1.7 ± 1.3 BT), exacerbation rate (0.9 ± 1.1 vs 0.9 ± 1.5), reduction in reliever use (-6.3 ± 10.5 vs -5.0 ± 8.8 puffs/day) or reduction in oral corticosteroids (-3.3 ± 7.5 vs - 5.8 ± 6.7 mg/day). The FEV₁ improved equally (160 ± 290 vs 150 ± 460 mL). Readmission or prolonged admission was observed in 18.2% of BT patients, whilst 25.5% of mepolizumab patients had discontinued treatment at 12 months, 14.9% due to an adverse event or non-compliance.

CONCLUSION

The results suggest that BT is as efficacious as mepolizumab for the treatment of severe asthma.

Smooth-muscle-derived WNT5A augments allergen-induced airway remodelling and Th2 type inflammation

Asthma is a heterogeneous disease characterized by chronic inflammation and structural changes in the airways. The airway smooth muscle (ASM) is responsible for airway narrowing and an important source of inflammatory mediators. We and others have previously shown that WNT5A mRNA and protein expression is higher in the ASM of asthmatics compared to healthy controls. Here, we aimed to characterize the functional role of (smooth muscle-derived) WNT5A in asthma. We generated a tet-ON smooth-muscle-specific WNT5A transgenic mouse model, enabling in vivo characterization of smooth-muscle-derived WNT5A in response to ovalbumin. Smooth muscle specific WNT5A overexpression showed a clear trend towards enhanced actin (α-SMA) expression in the ASM in ovalbumin challenged animals, but had no effect on collagen content. WNT5A overexpression in ASM also significantly enhanced the production of the Th2-cytokines IL4 and IL5 in lung tissue after ovalbumin exposure. In line with this, WNT5A increased mucus production, and enhanced eosinophilic infiltration and serum IgE production in ovalbumin-treated animals. In addition, CD4⁺ T cells of asthma patients and healthy controls were stimulated with WNT5A and changes in gene transcription assessed by RNA-seq. WNT5A promoted expression of 234 genes in human CD4⁺ T cells, among which the Th2 cytokine IL31 was among the top 5 upregulated genes. IL31 was also upregulated in response to smooth muscle-specific WNT5A overexpression in the mouse. In conclusion, smooth-muscle derived WNT5A augments Th2 type inflammation and remodelling. Our findings imply a pro-inflammatory role for smooth muscle-derived WNT5A in asthma, resulting in increased airway wall inflammation and remodelling.

Recent Developments In Bronchial Thermoplasty For Severe Asthma

PURPOSE

Bronchial thermoplasty is approved in many countries worldwide as a non-pharmacological treatment for severe asthma. This review summarizes recent publications on the selection of patients with severe asthma for bronchial thermoplasty, predictors of a beneficial response and developments in the procedure and discusses specific issues about bronchial thermoplasty including effectiveness in clinical practice, mechanism of action, cost-effectiveness, and place in management.

RESULTS

Bronchial thermoplasty is a treatment option for patients with severe asthma after assessment and management of causes of difficult-to-control asthma, such as nonadherence, poor inhaler technique, comorbidities, under treatment, and other behavioral factors. Patients treated with bronchial thermoplasty in clinical practice have worse baseline characteristics and comparable clinical outcomes to clinical trial data. Bronchial thermoplasty causes a reduction in airway smooth muscle mass although it is uncertain whether this effect explains its efficacy since other mechanisms of action may be relevant, such as alterations in airway epithelial, gland, and/or nerve function; improvements in small airway function; or a placebo effect. The cost-effectiveness of bronchial thermoplasty is greater in countries where the costs of hospitalization and emergency department are high. The place of bronchial thermoplasty in the management of severe asthma is not certain, although some experts propose that bronchial thermoplasty should be considered for patients with severe asthma associated with non-type 2 inflammation or who fail to respond favorably to biologic therapies targeting type 2 inflammation.

CONCLUSION

Bronchial thermoplasty is a modestly effective treatment for severe asthma after assessment and management of causes of difficult-to-control asthma. Asthma morbidity increases during and shortly after treatment. Follow-up studies provide reassurance on the long-term safety of the procedure. Uncertainties remain about predictors of response, mechanism(s) of action, and place in management of severe asthma.

The Role of HMGB1, a Nuclear Damage-Associated Molecular Pattern Molecule, in the Pathogenesis of Lung Diseases

Significance: High-mobility group protein box 1 (HMGB1), a ubiquitous nuclear protein, regulates chromatin structure and modulates the expression of many genes involved in the pathogenesis of lung cancer and many other lung diseases, including those that regulate cell cycle control, cell death, and DNA replication and repair. Extracellular HMGB1, whether passively released or actively secreted, is a danger signal that elicits proinflammatory responses, impairs macrophage phagocytosis and efferocytosis, and alters vascular remodeling. This can result in excessive pulmonary inflammation and compromised host defense against lung infections, causing a deleterious feedback cycle. Recent Advances: HMGB1 has been identified as a biomarker and mediator of the pathogenesis of numerous lung disorders. In addition, post-translational modifications of HMGB1, including acetylation, phosphorylation, and oxidation, have been postulated to affect its localization and physiological and pathophysiological effects, such as the initiation and progression of lung diseases. Critical Issues: The molecular mechanisms underlying how HMGB1 drives the pathogenesis of different lung diseases and novel therapeutic approaches targeting HMGB1 remain to be elucidated. Future Directions: Additional research is needed to identify the roles and functions of modified HMGB1 produced by different post-translational modifications and their significance in the pathogenesis of lung diseases. Such studies will provide information for novel approaches targeting HMGB1 as a treatment for lung diseases.

New Treatments for Asthma

Asthma is a complex, heterogeneous chronic airway disease with high prevalence of uncontrolled disease. New therapies, including biologics, are now available to treat T2 high asthma. Treatment of T2 low asthma remains a challenge. Asthma guidelines need be to updated to incorporate new therapeutics.

Toward clinically applicable biomarkers for asthma: An EAACI position paper

Inflammation, structural, and functional abnormalities within the airways are key features of asthma. Although these processes are well documented, their expression varies across the heterogeneous spectrum of asthma. Type 2 inflammatory responses are characterized by increased levels of eosinophils, FeNO, and type 2 cytokines in blood and/or airways. Presently, type 2 asthma is the best-defined endotype, typically found in patients with allergic asthma, but surprisingly also in nonallergic patients with (severe) asthma. The etiology of asthma with non-type 2 inflammation is less clear. During the past decade, targeted therapies, including biologicals and small molecules, have been increasingly integrated into treatment strategies of severe asthma. These treatments block specific inflammatory pathways or single mediators. Single or composite biomarkers help to identify patients who will benefit from these treatments. So far, only a few inflammatory biomarkers have been validated for clinical application. The European Academy of Allergy & Clinical Immunology Task Force on Biomarkers in Asthma was initiated to review different biomarker sampling methods and to investigate clinical applicability of new and existing inflammatory biomarkers (point-of-care) to support diagnosis, targeted treatment, and monitoring of severe asthma. Subsequently, we discuss existing and novel targeted therapies for asthma as well as applicable biomarkers.

European consensus meeting/statement on Bronchial Thermoplasty Who? Where? How?

BACKGROUND

Bronchial Thermoplasty (BT) is a bronchoscopic treatment for severe asthma. Following research trials there remains a need to guide BT treatment in clinical practice, specifically in the fields of patient assessment, selection and positioning of BT within the range of treatment modalities, BT treatment protocols and post-BT management and follow-up. Consensus statements can bridge the gap between evidence-based medicine and real world clinical practice.

METHODS

We performed a modified RAND consensus analysis using a baseline list of statements derived from ATS/ERS Guidelines on Severe Asthma, Cochrane review and UK commissioning guidance. A panel of 5 European BT experts, individually scored the statements and following a day of discussion, rescored a revised final list independently.

RESULTS

An initial list of 132 statements, were independently scored. These were modified to 108 following group discussion. Consensus/total agreement was reached for 68 (63%) of the statements; 8 (7.4%) statements achieving total disagreement. For only 17 statements, could some form of consensus not be achieved.

CONCLUSIONS

The consensus document could be applied to guide BT clinical practice and used to serve as a minimum acceptable level of assessment for BT, drive the development of clinical practice protocols and help define quality indicators.

Bulleyaconitine A Effectively Relieves Allergic Lung Inflammation in a Murine Asthmatic Model

Background

Bulleyaconitine A (BLA) has been widely used as analgesic against chronic inflammatory pain in China. However, its potential therapeutic role in asthma remains unclear. The purpose of this study was to investigate the effect of BLA on airway inflammation in mice with allergic asthma.

Material/Methods

Specific-pathogen-free (SPF) female Balb/c mice were randomly divided into the following 6 groups: (1) Control group (NC), (2) Asthma group (AS), (3) BLA-L group, (4) BLA-M group, (5) BLA-H group, and (6) Dexamethasone group. An asthma mouse model was established by administration of ovalbumin (OVA) and mice were sacrificed within 24 h after the last challenge. Enzyme-linked immunosorbent assay (ELISA) method was used to determine the relative expression levels of IgE and IgG in mouse serum. In addition, bronchoalveolar lavage fluid (BALF) was collected and IL-4, TNF-α, and MCP-1 levels were determined by ELISA. Furthermore, eosinophils, lymphocytes, and macrophages in BALF were classified and analyzed, and inflammatory cell infiltration in the airways of mice was determined by hematoxylin-eosin (HE) staining. The expression of NF-κB1 and PKC-δ in mouse lung tissue was determined by Western blot analysis.

Results

The levels of serum IgE and IgG in BLA- or Dex- treated mice were significantly reduced compared to those in the asthma (AS) group (P<0.01), whereas the levels of cytokines IL-4, TNF-α, and MCP-1 were significantly decreased (P<0.01). HE-staining showed that BLA significantly reduced inflammatory cell infiltration and mucus secretion in lung tissue. Moreover, BLA inhibited the expression of NF-κB1 and PKC-δ via the NF-κB signaling pathway in the lung.

Conclusions

Our data show that BLA activates PKC-δ/NF-κB to reduce airway inflammation in allergic asthma mice.

Patient-specific targeted bronchial thermoplasty: predictions of improved outcomes with structure-guided treatment

Bronchial thermoplasty is a recent treatment for asthma in which ablative thermal energy is delivered to specific large airways according to clinical guidelines. Therefore, current practice is effectively "blind," as it is not informed by patient-specific data. The present study seeks to establish whether a patient-specific approach based on structural or functional patient data can improve outcomes and/or reduce the number of procedures required for clinical efficacy. We employed a combination of extensive human lung specimens and novel computational methods to predict bronchial thermoplasty outcomes guided by structural or functional data compared with current clinical practice. Response to bronchial thermoplasty was determined from changes in airway responses to strong bronchoconstrictor simulations and flow heterogeneity after one or three simulated thermoplasty procedures. Structure-guided treatment showed significant improvement over current unguided clinical practice, with a single session of structure-guided treatment producing improvements comparable with three sessions of unguided treatment. In comparison, function-guided treatment did not produce a significant improvement over current practice. Structure-guided targeting of bronchial thermoplasty is a promising avenue for improving therapy and reinforces the need for advanced imaging technologies. The functional imaging-guided approach is predicted to be less effective presently, and we make recommendations on how this approach could be improved. NEW & NOTEWORTHY Bronchial thermoplasty is a recent treatment for asthma in which thermal energy is delivered via bronchoscope to specific airways in an effort to directly target airway smooth muscle. Current practice involves the treatment of a standard set of airways, unguided by patient-specific data. We consider the potential for guided treatments, either by functional or structural data from the lung, and show that treatment guided by structural data has the potential to improve clinical practice.

Competence in bronchial thermoplasty

Bronchial thermoplasty (BT) is an innovative non-pharmacological endoscopic treatment for patients with severe persistent asthma based on controlled heat release with a device called Alair™ Catheter (Boston Scientific, Natick, MA, USA). The Alair™ system is the first device that works by delivering radiofrequency or thermal energy to selectively reduce the amount of airway smooth muscle (ASM) in bronchi. Literature showed significant improvement in clinical outcomes such as symptom control, severe exacerbation rate, hospitalization, quality of life, and number of working or school days lost for asthma. Besides smooth muscle effects changes in inflammatory pattern after BT have been documented. Bronchial thermoplasty requires an experienced physician who had a proficiency training in bronchoscopy and had rigor, dexterity and a thorough knowledge of the airway anatomy. Furthermore, right selection of severe asthma patient is crucial in order to have best response after BT. This article reviews BT device description and how to perform the procedure. Criteria for right selection and management of patient before and after BT will be discussed.

TRPC1 intensifies house dust mite-induced airway remodeling by facilitating epithelial-to-mesenchymal transition and STAT3/NF-κB signaling

Airway remodeling with progressive epithelial alterations in the respiratory tract is a severe consequence of asthma. Although dysfunctional signaling transduction is attributed to airway inflammation, the exact mechanism of airway remodeling remains largely unknown. TRPC1, a member of the transient receptor potential canonical Ca²⁺ channel family, possesses versatile functions but its role in airway remodeling remains undefined. Here, we show that ablation of TRPC1 in mice alleviates airway remodeling following house dust mite (HDM) challenge with decreases in mucus production, cytokine secretion, and collagen deposition. HDM challenge induces Ca²⁺ influx via the TRPC1 channel, resulting in increased levels of signal transducer and activator of transcription 3 (STAT3) and proinflammatory cytokines. In contrast, STAT3 expression was significantly decreased in TRPC1^-/- mouse lungs compared with wild-type controls after HDM challenge. Mechanistically, STAT3 promotes epithelial-to-mesenchymal transition and increases mucin 5AC expression. Collectively, these findings identify TRPC1 as a modulator of HDM-induced airway remodeling via STAT3-mediated increase in mucus production, which provide new insight in our understanding of the molecular basis of airway remodeling, and identify novel therapeutic targets for intervention of severe chronic asthma.-Pu, Q., Zhao, Y., Sun, Y., Huang, T., Lin, P., Zhou, C., Qin, S., Singh, B. B., Wu, M. TRPC1 intensifies house dust mite-induced airway remodeling by facilitating epithelial-to-mesenchymal transition and STAT3/NF-κB signaling.

Therapeutic antibodies: A new era in the treatment of respiratory diseases?

Respiratory diseases affect millions of people worldwide, and account for significant levels of disability and mortality. The treatment of lung cancer and asthma with therapeutic antibodies (Abs) is a breakthrough that opens up new paradigms for the management of respiratory diseases. Antibodies are becoming increasingly important in respiratory medicine; dozens of Abs have received marketing approval, and many more are currently in clinical development. Most of these Abs target asthma, lung cancer and respiratory infections, while very few target chronic obstructive pulmonary disease - one of the most common non-communicable causes of death - and idiopathic pulmonary fibrosis. Here, we review Abs approved for or in clinical development for the treatment of respiratory diseases. We notably highlight their molecular mechanisms, strengths, and likely future trends.

Bronchial Thermoplasty in Severe Asthma: Best Practice Recommendations from an Expert Panel

Bronchial thermoplasty (BT) is a bronchoscopic treatment for patients with severe asthma who remain symptomatic despite optimal medical therapy. In this "expert best practice" paper, the background and practical aspects of BT are highlighted. Randomized, controlled clinical trials have shown BT to be safe and effective in reducing severe exacerbations, improving quality of life, and decreasing emergency department visits. Five-year follow-up studies have provided evidence of the functional stability of BT-treated patients with persistence of a clinical benefit. The Global Initiative for Asthma (GINA) guidelines state that BT can be considered as a treatment option for adult asthma patients at step 5. Patient selection for BT requires close collaboration between interventional pulmonologists and severe asthma specialists. Key patient selection criteria for BT will be reviewed. BT therapy is delivered in 3 separate bronchoscopy sessions at least 3 weeks apart, covering different regions of the lung separately. Patients are treated with 50 mg/day of prednisolone or equivalent for 5 days, starting treatment 3 days prior to the procedure. The procedure is performed under moderate-to-deep sedation or general anesthesia. At bronchos-copy a single-use catheter with a basket design is inserted through the instrument channel and the energy is delivered by a radiofrequency (RF) generator (AlairTM Bronchial Thermoplasty System). BT uses temperature-controlled RF energy to impact airway remodeling, including a reduction of excessive airway smooth muscle within the airway wall, which has been recognized as a predominant feature of asthma. The treatment should be performed in a systemic manner, starting at the most distal part of the (sub)segmental airway, then moving proximally to the main bronchi, ensuring that the majority of the airways are treated. In general, 40-70 RF activations are provided in the lower lobes, and between 50 and 100 activations in the upper lobes combined. The main periprocedural adverse events are exacerbation of asthma symptoms and increased cough and sputum production. Occasionally, atelectasis has been observed following the procedure. The long-term safety of BT is excellent. An optimized BT responder profile - i.e., which specific asthma phenotype benefits most - is a topic of current research.

Precision medicine in asthma: the role of bronchial thermoplasty

PURPOSE OF REVIEW

The inflammatory makeup of severe asthma is heterogeneous. Identification of the predominant cellular endotype via biomarkers can aid in the selection of more advanced therapies. This review is clinically focused on how to use these biomarkers to help select between biologic agents and/or bronchial thermoplasty.

RECENT FINDINGS

Several Th2 biomarkers exist for the detection of eosinophilic disease; however, the best biomarker for clinical practice is debatable depending upon local resources. Currently, there are three federal drug agency-approved biologic agents (omalizumab, mepolizumab and reslizumab) to treat severe asthma with frequent exacerbations despite standard medical therapy. Several others are either in clinical trials or in the development phase for the treatment of eosinophilic asthma. To date, agents targeting neutrophilic inflammation have been largely unsuccessful. Bronchial thermoplasty has emerged as an option for the treatment of severe asthma.

SUMMARY

The appropriate selection of patients through the use of eosinophilic biomarkers has led to significant reductions in exacerbations with the use of mAb therapy. Bronchial thermoplasty has also shown reductions in asthma exacerbations and improved quality of life; however, it is unclear which patients may respond best to this intervention.

An algorithmic approach for the treatment of severe uncontrolled asthma

A small subgroup of patients with asthma suffers from severe disease that is either partially controlled or uncontrolled despite intensive, guideline-based treatment. These patients have significantly impaired quality of life and although they constitute <5% of all asthma patients, they are responsible for more than half of asthma-related healthcare costs. Here, we review a definition for severe asthma and present all therapeutic options currently available for these severe asthma patients. Moreover, we suggest a specific algorithmic treatment approach for the management of severe, difficult-to-treat asthma based on specific phenotype characteristics and biomarkers. The diagnosis and management of severe asthma requires specialised experience, time and effort to comprehend the needs and expectations of each individual patient and incorporate those as well as his/her specific phenotype characteristics into the management planning. Although some new treatment options are currently available for these patients, there is still a need for further research into severe asthma and yet more treatment options.

Stepwise approach for the treatment of severe asthmahttp://ow.ly/rLPl30i0TyZ

Nonpharmacologic Therapy for Severe Persistent Asthma

The treatment of asthma largely depends on guideline-based pharmacologic therapies. However, nonpharmacologic therapies for asthma such as pulmonary rehabilitation, focused breathing techniques, and bronchial thermoplasty have an important, yet underappreciated, role. Structured pulmonary rehabilitation programs can reduce dyspnea and increase cardiopulmonary fitness. The educational component of these programs can ensure that therapies are being used appropriately, increase compliance, and decrease health care utilization. Studies have demonstrated a reduction in inflammatory mediators in patients with asthma who are engaged in an exercise program. Focused breathing techniques are commonly used by patients with asthma, yet benefit has not been clearly shown in randomized controlled trials. For the patients with severe asthma who are unresponsive to maximum medical therapy and have evidence of airway remodeling, bronchial thermoplasty has demonstrated long-term improvement in quality of life and reduction in severe exacerbations and health care utilization. Recent airway biopsy studies have demonstrated bronchial thermoplasty's disease-modifying effect on smooth muscle, inflammatory mediators, and bronchial nerve endings. These nonpharmacologic therapies are complementary to current guideline-based treatment, including the use of biologic modifiers, for severe asthma.

New approaches for identifying and testing potential new anti-asthma agents

Asthma is a chronic disease with significant heterogeneity in clinical features, disease severity, pattern of underlying disease mechanisms, and responsiveness to specific treatments. While the majority of asthmatic patients are controlled by standard pharmacological strategies, a significant subgroup has limited therapeutic options representing a major unmet need. Ongoing asthma research aims to better characterize distinct clinical phenotypes, molecular endotypes, associated reliable biomarkers, and also to develop a series of new effective targeted treatment modalities. Areas covered: The expanding knowledge on the pathogenetic mechanisms of asthma has allowed researchers to investigate a range of new treatment options matched to patient profiles. The aim of this review is to provide a comprehensive and updated overview of the currently available, new and developing approaches for identifying and testing potential treatment options for asthma management. Expert opinion: Future therapeutic strategies for asthma require the identification of reliable biomarkers that can help with diagnosis and endotyping, in order to determine the most effective drug for the right patient phenotype. Furthermore, in addition to the identification of clinical and inflammatory phenotypes, it is expected that a better understanding of the mechanisms of airway remodeling will likely optimize asthma targeted treatment.

Bronchial Thermoplasty: A Nonpharmacologic Therapy for Severe Asthma

Bronchial thermoplasty is an innovative treatment for patients with severe asthma and chronic airflow obstruction with an established long-term efficacy and safety profile. This review focuses on the role of bronchial thermoplasty in severe asthma, its mechanism of action, appropriate patient selection, current evidence, and recent developments of this therapy.

Bronchial thermoplasty and the role of airway smooth muscle: are we on the right direction?

Asthma is characterized by inflammation of the airways that includes eosinophils, basal membrane thickening, epithelial sloughing, vascular changes, smooth muscle hypertrophy and hyperplasia, and mucous gland hyperplasia. Recently, there have been studies on the role of hypersensitivity and inflammation in asthma, but the role of bronchial smooth muscle remains unclear. Bronchial thermoplasty is an endoscopic procedure that is approved by the US Food and Drug Administration (FDA) for the treatment of severe refractory asthma, based on the local delivery of radio frequency at 65°C to the airways, with the aim of controlling bronchospasm through a reduction of airway smooth muscle (ASM). Several recent studies have shown significant improvement in clinical outcomes of bronchial thermoplasty for asthma, including symptom control, reduction in exacerbation and hospitalization rates, improved quality of life, and reduction in number of working days or school days lost due to asthma. Data from these recent studies have shown reduction in ASM following bronchial thermoplasty and changes in inflammation patterns. It has also been argued that bronchial thermoplasty may have modulating effects on neuroendocrine epithelial cells, bronchial nerve endings, TRPV1 nerve receptors, and type-C unmyelinated fibers in the bronchial mucosa. This may involve interrupting the central and local reflexes responsible for the activation of bronchospasm in the presence of bronchial hyperreactivity. Several questions remain regarding the use of bronchial thermoplasty, mechanism of action, selection of appropriate patients, and long-term effects. In this review, the role of ASM in the pathogenesis of asthma and the key aspects of bronchial thermoplasty are discussed, with a focus on the potential clinical effects of this promising procedure, beyond the reduction in ASM.

Revisiting asthma therapeutics: focus on WNT signal transduction

Asthma is a complex disease of the airways that develops as a consequence of both genetic and environmental factors. This interaction has highlighted genes important in early life, particularly those that control lung development, such as the Wingless/Integrase-1 (WNT) signalling pathway. Although aberrant WNT signalling is involved with an array of human conditions, it has received little attention within the context of asthma. Yet it is highly relevant, driving events involved with inflammation, airway remodelling, and airway hyper-responsiveness (AHR). In this review, we revisit asthma therapeutics by examining whether WNT signalling is a valid therapeutic target for asthma.

Innovative treatments for severe refractory asthma: how to choose the right option for the right patient?

The increasing understanding of the molecular biology and the etiopathogenetic mechanisms of asthma helps in identification of numerous phenotypes and endotypes, particularly for severe refractory asthma. For a decade, the only available biologic therapy that met the unmet needs of a specific group of patients with severe uncontrolled allergic asthma has been omalizumab. Recently, new biologic therapies with different mechanisms of action and targets have been approved for marketing, such as mepolizumab. Other promising drugs will be available in the coming years, such as reslizumab, benralizumab, dupilumab and lebrikizumab. Moreover, since 2010, bronchial thermoplasty has been successfully introduced for a limited number of patients. This is a nonpharmacologic endoscopic procedure which is considered a promising therapy, even though several aspects still need to be clarified. Despite the increasing availability of new therapies, one of the major problems of each treatment is still the identification of the most suitable patients. This sudden abundance of therapeutic options, sometimes partially overlapping with each other, increases the importance to identify new biomarkers useful to guide the clinician in selecting the most appropriate patients and treatments, without forgetting the drug-economic aspects seen in elevated direct cost of new therapies. The aim of this review is, therefore, to update the clinician on the state of the art of therapies available for refractory asthma and, above all, to give useful directions that will help understand the different choices that sometimes partially overlap and to dispel the possible doubts that still exist.

MicroRNA-98 interferes with thrombospondin 1 expression in peripheral B cells of patients with asthma

Thrombospondin 1 (TSP1)-producing B cells are an important immune regulatory cell fraction in the body, which are compromised in a number of immune diseases. miRs are involved in the immune regulation. The present study aims to elucidate the mechanism by which miR-98 interferes with the expression of TSP1 in B cells of the peripheral blood system. In the present study, peripheral blood samples were collected from patients with allergic asthma. The B cells were isolated from the blood samples to be analyzed for the expression of miR-98 and TSP1. The results showed that the levels of miR-98 were higher, the levels of TSP1 were lower, in B cells isolated from the peripheral blood in patients with asthma. A negative correlation was identified between the data of miR-98 and TSP1 in B cells. Exposure to T helper (Th) 2 (Th2) cytokine, interleukin (IL)-13, increased the expression of miR-98 and suppressed the expression of TSP1 in peripheral B cells, which was abolished by knocking down the miR-98 gene. In conclusion, miR-98 can suppress the expression of TSP1 in the peripheral B cells of patients with allergic asthma.

Emerging understanding of the mechanism of action of Bronchial Thermoplasty in asthma

Bronchial Thermoplasty (BT) is an endoscopic treatment for moderate-to-severe asthma patients who are uncontrolled despite optimal medical therapy. Effectiveness of BT has been demonstrated in several randomized clinical trials. However, the asthma phenotype that benefits most of this treatment is unclear, partly because the mechanism of action is incompletely understood. BT was designed to reduce the amount of airway smooth muscle (ASM), but additional direct and indirect effects on airway pathophysiology are expected. This review will provide an overview of the different components of airway pathophysiology including remodeling, with the ASM as the key player. Current concepts in the understanding of BT clinical effectiveness with a focus on its impact on airway remodeling will be reviewed.

Prospects for new and emerging therapeutics in severe asthma: the role of biologics

INTRODUCTION

Asthma is a common and heterogeneous disease. While current conventional therapies are effective in the majority of the patients, a significant subgroup remain uncontrolled despite these treatments. Different biological agents are currently approved or undergoing development for treatment of asthma, including anti-IgE, anti-interleukin (IL)-5, anti-IL-13, anti-IL-4 and anti-thymic stromal lymphopoietin agents. This review will focus on the currently available evidence regarding the new and emerging biological agents in severe asthma. Areas covered: A non-systematic review of the available English-language literature regarding severe asthma and biological agents was performed. We summarized and discussed the current evidence about the use of new and emerging biological agents in severe asthma. Expert commentary: Because of the heterogeneity of response to therapy in refractory asthma it is of utmost importance to correctly estimate patient outcomes before starting biological therapy to make patient selection more effective. Currently, the decision of which biologic to initiate in patients with uncontrolled severe asthma should be made based on the atopic status, blood eosinophil and total IgE levels, exacerbation history, safety profile, cost, frequency and route of administration.

Lyn kinase represses mucus hypersecretion by regulating IL-13-induced endoplasmic reticulum stress in asthma

In asthma, mucus hypersecretion is thought to be a prominent pathological feature associated with widespread mucus plugging. However, the current treatments for mucus hypersecretion are often ineffective or temporary. The potential therapeutic targets of mucus hypersecretion in asthma remain unknown. Here, we show that Lyn is a central effector of endoplasmic reticulum stress (ER stress) and mucous hypersecretion in asthma. In Lyn-transgenic mice (Lyn-TG) and wild-type (WT) C57BL/6J mice exposed to ovalbumin (OVA), Lyn overexpression attenuates mucus hypersecretion and ER stress. Interleukin 13 (IL-13) induced MUC5AC expression by enhancing ER stress in vitro. Lyn serves as a negative regulator of IL-13-induced ER stress and MUC5AC expression. We further find that an inhibitor of ER stress, which is likely involved in the PI3K p85α/Akt pathway and NFκB activity, blocked MUC5AC expression in Lyn-knockdown cells. Furthermore, PI3K/Akt signaling is required for IL-13-induced ER stress and MUC5AC expression in airway epithelial cells. The ER stress regulation of MUC5AC expression depends on NFκB in Lyn-knockdown airway epithelial cells. Our studies indicate not only a concept of mucus hypersecretion in asthma that involves Lyn kinase but also an important therapeutic candidate for asthma.

Microheterogeneity of therapeutic monoclonal antibodies is governed by changes in the surface charge of the protein

It has previously been shown for individual antibodies, that the microheterogenity pattern can have a significant impact on various key characteristics of the product. The aim of this study to get a more generalized understanding of the importance of microheterogeneity. For that purpose, the charge variant pattern of various different commercially available therapeutic mAb products was compared using Cation-Exchange Chromatography with linear pH gradient antigen affinity, Fc-receptor affinity, antibody dependent cellular cytotoxicity (ADCC) and conformational stability. For three of the investigated antibodies, the basic charge variants showed a stronger binding affinity towards FcγRIIIa as well as an increased ADCC response. Differences in the conformational stability of antibody charge variants and the corresponding reference samples could not be detected by differential scanning calorimetry. The different biological properties of the mAb variants are therefore governed by changes in the surface charge of the protein and not by an altered structure. This can help to identify aspects of microheterogeneity that are critical for product quality and can lead to further improvements in the development and production of therapeutic antibody products.

The clinical profile of benralizumab in the management of severe eosinophilic asthma

Despite several therapeutic choices, 10–20% of patients with severe uncontrolled asthma do not respond to maximal best standard treatments, leading to a healthcare expenditure of up to 80% of overall costs for asthma. Today, there are new important therapeutic strategies, both pharmacological and interventional, that can result in improvement of severe asthma management, such as omalizumab, bronchial thermoplasty and other biological drugs, for example, mepolizumab, reslizumab and benralizumab. The availability of these new treatments and the increasing knowledge of the different asthmatic phenotypes and endotypes makes correct patient selection increasingly complex and important. In this article, we discuss the features of benralizumab compared with other anti-interleukin-5 biologics and omalizumab, the identification of appropriate patients, the safety profile and future developments.