Asthma and respiratory physiology: putting lung function into perspective

Association of Metabolites, Nutrients, and Toxins in Maternal and Cord Serum with Asthma, IgE, SPT, FeNO, and Lung Function in Offspring

The role of metabolites, nutrients, and toxins (MNTs) in sera at the end of pregnancy and of their association with offspring respiratory and allergic disorders is underexplored. Untargeted approaches detecting a variety of compounds, known and unknown, are limited. In this cohort study, we first aimed at discovering associations of MNTs in grandmaternal (F0) serum with asthma, immunoglobulin E, skin prick tests, exhaled nitric oxide, and lung function parameters in their parental (F1) offspring. Second, for replication, we tested the identified associations of MNTs with disorders in their grandchildren (F2-offspring) based on F2 cord serum. The statistical analyses were sex-stratified. Using liquid chromatography/high-resolution mass spectrometry in F0, we detected signals for 2286 negative-ion lipids, 59 positive-ion lipids, and 6331 polar MNTs. Nine MNTs (one unknown MNT) discovered in F0-F1 and replicated in F2 showed higher risks of respiratory/allergic outcomes. Twelve MNTs (four unknowns) constituted a potential protection in F1 and F2. We recognized MNTs not yet considered candidates for respiratory/allergic outcomes: a phthalate plasticizer, an antihistamine, a bile acid metabolite, tryptophan metabolites, a hemiterpenoid glycoside, triacylglycerols, hypoxanthine, and polyphenol syringic acid. The findings suggest that MNTs are aspirants for clinical trials to prevent adverse respiratory/allergic outcomes.

A systematic pharmacology-based in vivo study to reveal the effective mechanism of Yupingfeng in asthma treatment

BACKGROUND

The clinical effect of Yupingfeng (YPF) has been confirmed in asthma patients, however, it lacks a study to verify its pharmacological mechanism.

HYPOTHESIS/PURPOSE

To reveal the molecular basis and potential pharmacological mechanism of YPF in the treatment of asthma.

STUDY DESIGN AND METHODS

First, a systems pharmacology-based method integrating pharmacokinetic screening, target prediction, network analyses, GO and KEGG analyses were used for the systematic deciphering of the mechanism of YPF in asthma. Second, differentially expressed genes (DEGs) between asthma patients and healthy controls were identified by GEO2R online tool. Third, based on systems pharmacology and DEGs results, molecular docking was performed utilizing the Discovery Studio 2020 Client version to detect the binding capacity between compounds and targets. Finally, ovalbumin (OVA)-challenged C57BL/6 mice were treated with YPF or its effective compound to assess the predictions.

RESULTS

A total of 35 active compounds were filtered out, with 87 potential targets being identified for further analysis after target fishing and matching. Quercetin, kaempferol, and wogonin were identified as the main ingredients in YPF. The signaling pathways of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), tumor necrosis factor (TNF) and IL-17 were identified as the top signaling pathways in KEGG enrichment analysis. GEO2R tools of NCBI discovered five DEGs that overlapped with the therapeutic targets of YPF. Wogonin was proven to be the top active compound in YPF through the results of molecular docking. In vivo experiments indicated that YPF and wogonin significantly attenuated airway resistance and lung inflammation by decreasing the levels of inflammatory cytokines and key factors in PI3K/AKT, IL-17, and TNF signaling pathways.

CONCLUSIONS

YPF and its main active compound wogonin may exert some therapeutic effects on asthma inflammation through multiple molecular targets and signaling pathways including PI3K/AKT, IL-17 and TNF-α.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Eosinophil-derived neurotoxin: An asthma exacerbation biomarker in children

Background: Asthma is a heterogeneous disease, characterized by chronic airway inflammation. Asthma exacerbations (AE) are episodes characterized by a progressive increase in symptoms of shortness of breath, cough, wheezing, or chest tightness with a decrease in lung function. There have been previous studies that examined the role of eosinophil-derived neurotoxin (EDN) in asthma, but there have been no studies of the role of EDN in children experiencing AE. Objective: In this study, we aimed to examine the association of EDN with lung function and prognosis in children admitted for severe AE. Methods: We enrolled 82 children who were admitted for severe AE at two different university hospitals in South Korea between January 2018 and December 2019. Blood tests, including white blood cell count, myeloperoxidase (MPO), total eosinophil count, EDN, C-reactive protein (CRP) level, and interleukin (IL) 4, IL-5, IL-10 values, and lung function were measured on admission and at discharge in each patient. Results: We observed significant decreases in the levels of MPO, EDN, CRP, and IL-4, with significant improvement in lung function after treatment. We then classified the subjects into two groups of different clinical phenotypes: eosinophilic asthma exacerbation (EAE) group and non-EAE group. EDN levels were higher and lung functions were lower in the EAE group. Also, we found that the EDN level was a significant biomarker useful for predicting the number of days for hospital stay. Conclusion: We found that EDN can act as a biomarker that reflects lung function, and that EDN could act as a prognostic biomarker, which demonstrated the complex role of EDN in children experiencing AE.

Asthma and Lung Mechanics

This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.

Dismantling airway disease with the use of new pulmonary function indices

We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care.

In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed.

Spirometry is used to diagnose and manage airway disease such as asthma and COPD, but relates poorly to symptoms, lacks sensitivity and is effort dependent. FOT and MBNW are emerging clinical lung function tests that help us dismantle disease mechanisms.http://ow.ly/nM0G30nS6Ct

Fibroblast gene expression following asthmatic bronchial epithelial cell conditioning correlates with epithelial donor lung function and exacerbation history

Airway remodeling may contribute to decreased lung function in asthmatic children. Bronchial epithelial cells (BECs) may regulate fibroblast expression of extracellular matrix (ECM) constituents and fibroblast-to-myofibroblast transition (FMT). Our objective was to determine if human lung fibroblast (HLF) expression of collagen I (COL1A1), hyaluronan synthase 2 (HAS2), and the FMT marker alpha-smooth muscle actin (α-SMA) by HLFs conditioned by BECs from asthmatic and healthy children correlate with lung function measures and exacerbation history among BEC donors. BECs from asthmatic (n = 23) and healthy children (n = 15) were differentiated at an air-liquid interface (ALI) and then co-cultured with HLFs for 96 hours. Expression of COL1A1, HAS2, and α-SMA by HLFs was determined by quantitative polymerase chain reaction (qPCR). FMT was quantified by measuring HLF cytoskeletal α-SMA by flow cytometry. Pro-collagen Iα1, hyaluronan (HA), and PGE₂ were measured in BEC-HLF supernatant. Correlations between lung function measures of BEC donors, and COL1A1, HAS2, and α-SMA gene expression, as well as supernatant concentrations of HA, pro-collagen Iα1, hyaluronan (HA), and PGE₂ were assessed. We observed that expression of α-SMA and COL1A1 by HLFs co-cultured with asthmatic BECs was negatively correlated with BEC donor lung function. BEC-HLF supernatant concentrations of pro-collagen Iα1 were negatively correlated, and PGE₂ concentrations positively correlated, with asthmatic BEC donor lung function. Expression of HAS2, but not α-SMA or COL1A1, was greater by HLFs co-cultured with asthmatic BECs from donors with a history of severe exacerbations than by HLFs co-cultured with BECs from donors who lacked a history of severe exacerbations. In conclusion, α-SMA and COL1A1 expression by HLFs co-cultured with BECs from asthmatic children were negatively correlated with lung function measures, supporting our hypothesis that epithelial regulation of HLFs and airway deposition of ECM constituents by HLFs contributes to lung function deficits among asthmatic children. Furthermore, epithelial regulation of airway HAS2 may influence the susceptibility of children with asthma to experience severe exacerbations. Finally, epithelial-derived PGE₂ is a potential regulator of airway FMT and HLF production of collagen I that should be investigated further in future studies.

Factors reducing omalizumab response in severe asthma

BACKGROUND

Despite adding Omalizumab to conventional therapy, several severe asthmatics still show poor disease control. We investigated the factors that may affect a reduced Omalizumab response in a large population of severe asthmatics.

METHODS

340 patients were retrospectively evaluated. FEV₁%, FVC%, Asthma Control Test (ACT), fractional exhaled nitric oxide (FENO), possible step-downs/step-ups of concomitant therapies, exacerbations, disease control levels, ICS doses and SABA use, observed at the end of treatment, were considered as a response to Omalizumab.

RESULTS

Age was an independent risk factor for a reduced response concerning FEV₁%, FVC%, ACT and for a lower asthma control. Obesity (vs normal weight) was a determinant condition for exacerbations (OR:3.114[1.509-6.424], p = 0.002), for a disease partial/no control (OR:2.665[1.064-6.680], p = 0.036), for excessive SABA use (OR:4.448[1.837-10.768], p = 0.002) and for an unchanged/increased level of concomitant asthma medications. Furthermore, obesity also reduced the response in FEV₁ (β = -6.981,p = 0.04), FVC (β = -11.689,p = 0.014) and ACT (β = -2.585, p = 0.027) and was associated with a higher FENO level (β = 49.045,p = 0.040). Having at least one comorbidity was a risk factor for exacerbations (OR:1.383[1.128-1.697], p = 0.008) and for an ACT <20 (OR:2.410[1.071-3.690], p = 0.008). Specifically, chronic heart disease was associated with both a lower ACT and FVC% whereas gastroesophageal reflux with a partial/no asthma control. Nasal polyps were a predisposing factor leading both to exacerbations and to the use of higher inhaled corticosteroids doses. Moreover, smoking habits, pollen or dog/cat dander co-sensitizations may negatively influence Omalizumab response.

CONCLUSION

Age, obesity, comorbidities, smoking habits, nasal polyps, allergic poly-sensitization might reduce Omalizumab effectiveness independently to other asthma-influencing factors.

Airway Remodeling and Hyperreactivity in a Model of Bronchopulmonary Dysplasia and Their Modulation by IL-1 Receptor Antagonist

Bronchopulmonary dysplasia (BPD) is a chronic disease of extreme prematurity that has serious long-term consequences including increased asthma risk. We earlier identified IL-1 receptor antagonist (IL-1Ra) as a potent inhibitor of murine BPD induced by combining perinatal inflammation (intraperitoneal LPS to pregnant dams) and exposure of pups to hyperoxia (fraction of inspired oxygen = 0.65). In this study, we determined whether airway remodeling and hyperresponsiveness similar to asthma are evident in this model, and whether IL-1Ra is protective. During 28-day exposure to air or hyperoxia, pups received vehicle or 10 mg/kg IL-1Ra by daily subcutaneous injection. Lungs were then prepared for histology and morphometry of alveoli and airways, or for real-time PCR, or inflated with agarose to prepare precision-cut lung slices to visualize ex vivo intrapulmonary airway contraction and relaxation by phase-contrast microscopy. In pups reared under normoxic conditions, IL-1Ra treatment did not affect alveolar or airway structure or airway responses. Pups reared in hyperoxia developed a severe BPD-like lung disease, with fewer, larger alveoli, increased subepithelial collagen, and increased expression of α-smooth muscle actin and cyclin D1. After hyperoxia, methacholine elicited contraction with similar potency but with an increased maximum reduction in lumen area (air, 44%; hyperoxia, 89%), whereas dilator responses to salbutamol were maintained. IL-1Ra treatment prevented hyperoxia-induced alveolar disruption and airway fibrosis but, surprisingly, not the increase in methacholine-induced airway contraction. The current study is the first to demonstrate ex vivo airway hyperreactivity caused by systemic maternal inflammation and postnatal hyperoxia, and it reveals further preclinical mechanistic insights into IL-1Ra as a treatment targeting key pathophysiological features of BPD.

Avoiding misdiagnosis in patients with dyspnea and wheezing: a case report illustrating the clinical implications of fixation error

Background

Bronchial asthma is a heterogeneous respiratory condition which can be mimicked by a wide range of pathologies including upper airways stenosis. The accurate diagnosis of asthma, as with other conditions, may be influenced by fixation errors, which are common in medicine and occur when a physician concentrates on only one element of a clinical case without considering other relevant aspects. Here we report a challenging case characterized by the contemporaneous presence of a common disease, asthma, together with a rare respiratory disease, idiopathic tracheal stenosis.

Case presentation

The 56-year-old female patient, a former smoker, was referred to our outpatient clinic for exertional dyspnea and persistent wheezing. There were no other respiratory or systemic symptoms over the past three months, and a psychological component was suspected. Spirometry with flow-volume evaluation and bronchoscopy were the key elements to establish the diagnoses and provide treatments. Once the diagnosis of asthma was confirmed, the combination of the anti-inflammatory corticosteroid fluticasone and the rapid-acting bronchodilator formoterol in a single inhaler effectively controlled the patient’s symptoms, confirming the favorable efficacy and safety profile which are reflected in the recommendations of the international guidelines.

Conclusions

In this paper we describe the clinical investigations and interventions that eventually confirmed a diagnosis of asthma complicated by an idiopathic tracheal stenosis and led to effective treatment of the patient. Awareness of fixation error may avoid misdiagnosis in patients with respiratory disease and a complicated history at presentation.

Epidemiology and Pulmonary Physiology of Severe Asthma

The epidemiology and physiology of severe asthma are inherently linked because of varying phenotypes and expressions of asthma throughout the population. To understand how to better treat severe asthma, we must use both population data and physiologic principles to individualize therapies among groups with similar expressions of this disease.

Forced oscillation, integer and fractional-order modeling in asthma

The purpose of this study was to evaluate the use of fractional-order (FrOr) modeling in asthma. To this end, three FrOr models were compared with traditional parameters and an integer-order model (InOr). We investigated which model would best fit the data, the correlation with traditional lung function tests and the contribution to the diagnostic of airway obstruction. The data consisted of forced oscillation (FO) measurements obtained from healthy (n=22) and asthmatic volunteers with mild (n=22), moderate (n=19) and severe (n=19) obstructions. The first part of this study showed that a FrOr was the model that best fit the data (relative distance: FrOr=4.3±2.4; InOr=5.1±2.6%). The correlation analysis resulted in reasonable (R=0.36) to very good (R=0.77) associations between FrOr parameters and spirometry. The closest associations were observed between parameters related to peripheral airway obstruction, showing a clear relationship between the FrOr models and lung mechanics. Receiver-operator analysis showed that FrOr parameters presented a high potential to contribute to the detection of the mild obstruction in a clinical setting. The accuracy [area under the Receiver Operating Characteristic curve (AUC)] observed in these parameters (AUC=0.954) was higher than that observed in traditional FO parameters (AUC=0.732) and that obtained from the InOr model (AUC=0.861). Patients with moderate and severe obstruction were identified with high accuracy (AUC=0.972 and 0.977, respectively). In conclusion, the results obtained are in close agreement with asthma pathology, and provide evidence that FO measurement associated with FrOr models is a non-invasive, simple and radiation-free method for the detection of biomechanical abnormalities in asthma.

What long-term changes in lung function can tell us about asthma control

Asthma severity is typically classified according to lung function, but asthma control in relation to lung function is often harder to define. In this paper, we will review how lung function measured at rest, as well as over time, relates to asthma control. We will explore not only conventional lung function as measured by spirometry, such as peak expiratory flow and forced expiratory volume in 1 s, but also more sophisticated measurements of peripheral airway function related to respiratory system impedance and ventilation heterogeneity. In particular, we will review the emerging area of assessing the fluctuation of lung function over time and how it may correlate to both past and future asthma control.

Non-culturable bioaerosols in indoor settings: Impact on health and molecular approaches for detection

Despite their significant impact on respiratory health, bioaerosols in indoor settings remain understudied and misunderstood. Culture techniques, predominantly used for bioaerosol characterisation in the past, allow for the recovery of only a small fraction of the real airborne microbial burden in indoor settings, given the inability of several microorganisms to grow on agar plates. However, with the development of new tools to detect non-culturable environmental microorganisms, the study of bioaerosols has advanced significantly. Most importantly, these techniques have revealed a more complex bioaerosol burden that also includes non-culturable microorganisms, such as archaea and viruses. Nevertheless, air quality specialists and consultants remain reluctant to adopt these new research-developed techniques, given that there are relatively few studies found in the literature, making it difficult to find a point of comparison. Furthermore, it is unclear as to how this new non-culturable data can be used to assess the impact of bioaerosol exposure on human health. This article reviews the literature that describes the non-culturable fraction of bioaerosols, focussing on bacteria, archaea and viruses, and examines its impact on bioaerosol-related diseases. It also outlines available molecular tools for the detection and quantification of these microorganisms and states various research needs in this field.