New insights into the pathophysiology of the small airways in asthma

The Saudi initiative for asthma - 2024 update: Guidelines for the diagnosis and management of asthma in adults and children

The Saudi Initiative for Asthma 2024 (SINA-2024) is the sixth version of asthma guidelines for the diagnosis and management of asthma for adults and children that was developed by the SINA group, a subsidiary of the Saudi Thoracic Society. The main objective of the SINA is to have guidelines that are up-to-date, simple to understand, and easy to use by healthcare workers dealing with asthma patients. To facilitate achieving the goals of asthma management, the SINA Panel approach is mainly based on the assessment of symptom control and risk for both adults and children. The approach to asthma management is aligned for age groups: adults, adolescents, children aged 5-12 years, and children aged <5 years. SINA guidelines have focused more on personalized approaches reflecting a better understanding of disease heterogeneity with the integration of recommendations related to biologic agents, evidence-based updates on treatment, and the role of immunotherapy in management. The medication appendix has also been updated with the addition of recent evidence, new indications for existing medication, and new medications. The guidelines are constructed based on the available evidence, local literature, and the current situation at national and regional levels. There is also an emphasis on patient-doctor partnership in the management that also includes a self-management plan.

Anatomical and histopathological approaches to asthma phenotyping

Asthma is typically characterized by variable respiratory symptoms and airflow limitation. Along with the pathophysiology and symptoms are immunological and inflammatory processes. The last decades research has revealed that the immunology of asthma is highly heterogeneous. This has clinical consequences and identification of immunological phenotypes is currently used to guide biological treatment. The focus of this review is on another dimension of asthma diversity, namely anatomical heterogeneity. Immunopathological alterations may go beyond the central airways to also involve the distal airways, the alveolar parenchyma, and pulmonary vessels. Also, extrapulmonary tissues are affected. The anatomical distribution of inflammation in asthma has remained relatively poorly discussed despite its potential implication on both clinical presentation and response to treatment. There is today evidence that a significant proportion of the asthma patients has small airway disease with type 2 immunity, eosinophilia and smooth muscle infiltration of mast cells. The small airways in asthma are also subjected to remodelling, constriction, and luminal plugging, events that are likely to contribute to the elevated distal airway resistance seen in some patients. In cases when the inflammation extends into the alveolar parenchyma alveolar FCER1-high mast cells, eosinophilia, type 2 immunity and activated alveolar macrophages, together with modest interstitial remodelling, create a complex immunopathological picture. Importantly, the distal lung inflammation in asthma can be pharmacologically targeted by use of inhalers with more distal drug deposition. Biological treatments, which are readily distributed to the distal lung, may also be beneficial in eligible patients with more severe and anatomically widespread disease.

Treatment outcome clustering patterns correspond to discrete asthma phenotypes in children

Despite widely and regularly used therapy asthma in children is not fully controlled. Recognizing the complexity of asthma phenotypes and endotypes imposed the concept of precision medicine in asthma treatment. By applying machine learning algorithms assessed with respect to their accuracy in predicting treatment outcome, we have successfully identified 4 distinct clusters in a pediatric asthma cohort with specific treatment outcome patterns according to changes in lung function (FEV₁ and MEF₅₀), airway inflammation (FENO) and disease control likely affected by discrete phenotypes at initial disease presentation, differing in the type and level of inflammation, age of onset, comorbidities, certain genetic and other physiologic traits. The smallest and the largest of the 4 clusters- 1 (N = 58) and 3 (N = 138) had better treatment outcomes compared to clusters 2 and 4 and were characterized by more prominent atopic markers and a predominant allelic (A allele) effect for rs37973 in the GLCCI1 gene previously associated with positive treatment outcomes in asthmatics. These patients also had a relatively later onset of disease (6 + yrs). Clusters 2 (N = 87) and 4 (N = 64) had poorer treatment success, but varied in the type of inflammation (predominantly neutrophilic for cluster 4 and likely mixed-type for cluster 2), comorbidities (obesity for cluster 2), level of systemic inflammation (highest hsCRP for cluster 2) and platelet count (lowest for cluster 4). The results of this study emphasize the issues in asthma management due to the overgeneralized approach to the disease, not taking into account specific disease phenotypes.

Unravelling the complexity of tissue inflammation in uncontrolled and severe asthma

PURPOSE OF REVIEW

The clinical and inflammatory heterogeneity in asthma constitutes a major challenge for improved treatment. This review describes the nature of the inflammatory complexity and how it can be decoded to yield improved disease understanding and personalized treatment. The focus is on the difficult task of revealing the immunological complexity as it occurs inside diseased patient tissues.

RECENT FINDINGS

The inflammatory heterogeneity in asthma stretches beyond the classical division into allergic Th2 eosinophilic versus Th1 and/or Th17 neutrophilic (or paucigranulocytic) phenotypes. Rather than having one distinct type of inflammation, many patients display a patchwork of overlapping immune signatures. The patient diversity is further increased by differences in regard of distal lung involvement. Faced with this staggering complexity, calls have been made for a pragmatic biomarker-guided identification of treatable traits. In parallel, novel high-dimensional analyses and multiplex imaging aid the long-term goal of decoding the underlying molecular endotypes.

SUMMARY

Asthma is vastly heterogeneous with multiple and superimposed inflammatory and anatomical phenotypes. Despite the intensive research and introduction of highly immune-selective dugs, basic questions remain; especially as still too many of today's uncontrolled patients remain poorly understood. Here, pragmatic biomarker strategies, combined with novel methodological approaches that ultimately reveal the complete immunological complexity, will pave the way for improved differential diagnosis and personalized medication.

The Saudi Initiative for Asthma - 2019 Update: Guidelines for the diagnosis and management of asthma in adults and children

This is the fourth version of the updated guidelines for the diagnosis and management of asthma, developed by the Saudi Initiative for Asthma (SINA) group, a subsidiary of the Saudi Thoracic Society. The main objective of the SINA is to have guidelines that are up to date, simple to understand, and easy to use by healthcare workers dealing with asthma patients. To facilitate achieving the goals of asthma management, the SINA panel approach is mainly based on the assessment of symptom control and risk for both adults and children. The approach to asthma management is now more aligned for different age groups. The guidelines have focused more on personalized approaches reflecting better understanding of disease heterogeneity with integration of recommendations related to biologic agents, evidence-based updates on treatment, and role of immunotherapy in management. The medication appendix has also been updated with the addition of recent evidence, new indications for existing medication, and new medications. The guidelines are constructed based on the available evidence, local literature, and current situation at national and regional levels. There is also an emphasis on patient–doctor partnership in the management that also includes a self-management plan.

Lung clearance index is elevated in young children with symptom-controlled asthma

BACKGROUND

Pulmonary function testing has been recommended as an adjunct to symptom monitoring for assessment of asthma control. Lung clearance index (LCI) measures ventilation inhomogeneity and is thought to represent changes in the small airways. It has been proposed as a useful early marker of airway disease in asthmatic subjects, and determining it is feasible in preschool children. This study aims to assess whether LCI remains elevated in symptomatically controlled asthmatic children with a history of severe asthma, compared with healthy controls. A secondary aim was to determine whether the results were consistent across the preschool and school-aged populations.

METHODS

Using a case-control design, we compared 33 children with currently well-controlled symptoms who had a history of severe asthma, to 45 healthy controls (age 3-15 years) matched by age, height, and sex. We performed multiple breath washout tests using sulfur hexafluoride as a tracer gas, to determine their LCI and Scond values.

RESULTS

In the overall study, LCI z-score values were on average 0.86 units (95% confidence interval: 0.24-1.47, P = 0.01, t-test) higher in children with a history of severe asthma with current well-controlled symptoms compared with healthy controls. In addition, within the subgroup of preschool children (age ≤ 6), the asthmatic had significantly higher LCI z-score values than their healthy controls peers (mean (SD), 0.57 (2.18) vs -1.10 (1.00), P = 0.03, t-test). Twenty-seven percent (27%; 9/33) of subjects had an LCI value greater than the upper limit of our healthy controls despite being symptom controlled. Amongst preschool children, 5 (42%; 5/12) of the asthmatic children had abnormal LCI at the individual level.

CONCLUSIONS

LCI is elevated in children with asthma, which may be driven by differences in the preschool population. LCI may be useful in defining preschool asthma endotypes with persistent ventilation inhomogeneity despite symptomatic control.

Changes in mucin 1 expression in a rat model of allergic airway inflammation

PURPOSE

To explore the distribution and expressional changes of mucin 1 (Muc1) in airway of rats with allergic airway inflammation.

MATERIALS AND METHODS

Ovalbumin (OVA) was used to induce acute allergic inflammation in male Wistar rats. The distributions and expressions of Muc1 in lungs of normal and model rats were assessed by immunohistochemical staining and western blotting, respectively.

RESULTS

Immunohistochemical staining showed that Muc1 distributed in airway epithelial cells with ciliates, but not those nonciliated cells. Mucin 1 protein expression in the lung was increased during the development of allergic airway inflammation when compared with the normal rats.

CONCLUSION

Mucin 1 distributes in the airway epithelial cells with ciliates and the expressional increase of Muc1 in lung may imply its functions on allergic inflammatory episodes.

The Saudi Initiative for Asthma - 2016 update: Guidelines for the diagnosis and management of asthma in adults and children

This is an updated guideline for the diagnosis and management of asthma, developed by the Saudi Initiative for Asthma (SINA) group, a subsidiary of the Saudi Thoracic Society. The main objective of SINA is to have guidelines that are up to date, simple to understand and easy to use by nonasthma specialists, including primary care and general practice physicians. SINA approach is mainly based on symptom control and assessment of risk as it is the ultimate goal of treatment. The new SINA guidelines include updates of acute and chronic asthma management, with more emphasis on the use of asthma control in the management of asthma in adults and children, inclusion of a new medication appendix, and keeping consistency on the management at different age groups. The section on asthma in children is rewritten and expanded where the approach is stratified based on the age. The guidelines are constructed based on the available evidence, local literature, and the current situation in Saudi Arabia. There is also an emphasis on patient-doctor partnership in the management that also includes a self-management plan.

An example of using a decision making framework designed for non-medical prescribers as a method for enhancing prescribing safety for inhaled corticosteroids (ICS)

Non-medical prescribing is needed especially with the increased demand for health care and the physicians' time constrains. Also, it is not well regulated in Saudi Arabia unlike the United Kingdom. This report aims to demonstrate the urged need for regulations to maintain a safe non-medical prescribing process. It also adapts the single competency framework provided by the United Kingdom national prescribing centre (NPC, 2012) to be utilised by the respiratory therapist for a safe prescribing process for inhaled corticosteroids (ICS) to control adult asthma as an example. The framework is thought to be an effective tool for safe non-medical prescribing and it is highly recommended to develop a national Saudi framework to maintain the patients' safety and utilise resources.

Effect of gastroesophageal reflux disease on disease severity and characteristics of lung functional changes in patients with asthma

INTRODUCTION

Almost one third of patients with asthma have symptomatic evidence for coexisting gastroesophageal reflux disease (GERD), which is thought to be aggravating factor in asthma at least in some cases. We investigated the impact of coexisting GERD on asthma severity and parameters of lung function.

METHODS

Ninety two asthma patients diagnosed according to ATS criteria were studied. After full history and physical examination, asthma severity was measured in each patient using asthma control test (ACT). GERD symptoms was verified in each patient. Impulse oscillometry (IOS) and lung volume studies (using body-plethysmography and IOS) were performed. The difference between total airway resistance (TAWR) indicated by resistance at 5 Hz and central airway resistance (CAWR) as indicated by resistance at 20 Hz in oscillometry was calculated and considered as representative of resistance at peripheral airways (PAWR). The relationship between the presences of GERD symptoms, ACT score and parameters of lung function were analyzed.

RESULTS

PAWR and TAWR were both significantly higher in asthmatic patients with GERD symptoms than patients without GERD symptoms (256.64±161.21 versus 191.68±98.64; P=0.02, and 102.73±122.39 versus 56.76±71.43; P=0.01, respectively). However, no significant difference was noted in mean values of ACT, FEV1 (forced expiratory volume in 1 sec), FVC (forced vital capacity), PEF (peak expiratory flow), and CAWR in these two groups.

CONCLUSION

These findings suggest that the severity of asthma as measured by ACT score is not different in patients with and without GERD symptoms. However, total and peripheral airway resistance measured by IOS is significantly higher in asthmatic patients with GERD symptoms.

Asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS): current literature review

Asthma and chronic obstructive pulmonary disease (COPD) are chronic diseases, very common in general population. These obstructive airway illnesses are manifested with chronic inflammation affecting the whole respiratory tract. Obstruction is usually intermittent and reversible in asthma, but is progressive and irreversible in COPD. Asthma and COPD may overlap and converge, especially in older people [overlap syndrome-asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS)]. Although ACOS accounts approximately 15-25% of the obstructive airway diseases, is not well recognised because of the structure of clinical trials. COPD studies exclude asthma patients and asthma studies exclude COPD patients, respectively. It is crucial to define asthma, COPD and overlap syndrome (ACOS), as notable clinical entities, which they share common pathologic and functional features, but they are characterized from differences in lung function, acute exacerbations, quality of life, hospital impact and mortality.

Effects of inhaled fluticasone on intraocular pressure and central corneal thickness in asthmatic children without a family history of glaucoma

Purpose:

The aim of this study is to report the effects of fluticasone-inhaled corticosteroid on intraocular pressure (IOP) and central corneal thickness (CCT) of asthmatic children without a family history of glaucoma.

Materials and Methods:

In this prospective study, 93 children were divided into two groups: 69 asthmatic children with no family history of glaucoma who were taking inhaled fluticasone propionate 250 μg daily for at least 6 months (Group 1) and 24 age-matched control subjects without asthma (Group 2). Three measurements each, of IOP and CCT, were performed with a hand-held noncontact tonometer and a noncontact specular microscope, respectively, over a 12-week period. The order of IOP and CCT measured were randomized at each visit. Between-group comparison and the relationship between CCT and IOP measurements were investigated. P < 0.05 was statistically significant.

Results:

The mean age was 8 ± 2.4 years (range, 5–15 years) and 9 ± 2.9 years (range, 5–15 years) for Groups 1 and 2, respectively (P = 0.1337). The mean IOP was 14 ± 3.3 mmHg (range, 10–24 mmHg) and 14 ± 2.9 mmHg (range, 11–22 mmHg) for Groups 1 and 2, respectively (P = 0.3626). The mean CCT was 531 ± 30.1 μm (range, 467–601 μm) and 519 ± 47.0 μm (range, 415589 μm) for Groups 1 and 2, respectively (P = 0.1625). There was a weak but statistically significant correlation between IOP and CCT in Group 1 (Pearson's R = 0.3580, P = 0.0025).

Conclusions:

Inhaled fluticasone at the regular dose used in this study over a short period (6–24 months) was not associated with a significant effect on CCT and IOP measured with noncontact devices in asthmatic children between 5 and 15 years, without a family history of glaucoma. A weak correlation between IOP and CCT values in asthmatic children did exist.

The Saudi initiative for asthma - 2012 update: Guidelines for the diagnosis and management of asthma in adults and children

This an updated guidelines for the diagnosis and management of asthma, developed by the Saudi Initiative for Asthma (SINA) group, a subsidiary of the Saudi Thoracic Society. The main objective of SINA is to have updated guidelines, which are simple to understand and easy to use by non-asthma specialists, including primary care and general practice physicians. This new version includes updates of acute and chronic asthma management, with more emphasis on the use of Asthma Control Test in the management of asthma, and a new section on "difficult-to-treat asthma." Further, the section on asthma in children was re-written to cover different aspects in this age group. The SINA panel is a group of Saudi experts with well-respected academic backgrounds and experience in the field of asthma. The guidelines are formatted based on the available evidence, local literature, and the current situation in Saudi Arabia. There was an emphasis on patient-doctor partnership in the management that also includes a self-management plan. The approach adopted by the SINA group is mainly based on disease control as it is the ultimate goal of treatment.

Alveolar mast cells shift to an FcεRI-expressing phenotype in mild atopic asthma: a novel feature in allergic asthma pathology

BACKGROUND

A unique feature of alveolar mast cells is their low high-affinity IgE receptor (FcεRI) expression. Recent discoveries in uncontrolled asthma suggest that the appearance of FcεRI-expressing alveolar mast cells may be a novel disease-specific feature of allergic asthma. This study investigates whether increased FcεRI-expressing alveolar mast cells are present in patients with mild allergic asthma or even in non-asthmatic allergic rhinitis patients (AR) who have developed bronchial hyperactivity (BHR).

METHODS

Bronchial and alveolar tissues were obtained from healthy controls, AR patients with or without BHR, and AR patients with concurrent asthma. Samples were processed for immunohistochemical identification of MC(T) and MC(TC) and expression of FcεRI and surface-bound IgE.

RESULTS

Bronchial mast cell expression of FcεRI was high in all groups. In contrast, in the alveolar tissue, the expression of FcεRI on mast cells was low in healthy controls and in the AR patient groups, whereas a high expression was present in AR patients with concurrent asthma (P = 0.006 compared to controls). The asthmatics had a 29-fold increase in numbers (P = 0.006) and a 19-fold increase in proportion (P = 0.007) of alveolar mast cells that expressed surface-bound IgE.

CONCLUSIONS

The present data show that alveolar mast cells in patients with mild atopic asthma, but not atopic patients with AR, have turned into a highly FcεRI- and IgE-expressing phenotype. These data support the hypothesis that increased FcεRI expression on alveolar mast cells is a novel disease-specific feature of allergic asthma that is important for understanding asthma phenotypes and designing new therapeutic strategies.

Effect of antigenic exposure on airway smooth muscle remodeling in an equine model of chronic asthma

Recent studies suggest that airway smooth muscle remodeling is an early event in asthma, but whether it remains a dynamic process late in the course of the disease is unknown. Moreover, little is known about the effects of an antigenic exposure on chronically established smooth muscle remodeling. We measured the effects of antigenic exposure on airway smooth muscle in the central and peripheral airways of horses with heaves, a naturally occurring airway disease that shares similarities with chronic asthma. Heaves-affected horses (n = 6) and age-matched control horses (n = 5) were kept on pasture before being exposed to indoor antigens for 30 days to induce airway inflammation and bronchoconstriction. Peripheral lung and endobronchial biopsies were collected before and after antigenic exposure by thoracoscopy and bronchoscopy, respectively. Immunohistochemistry and enzymatic labeling were used for morphometric analyses of airway smooth muscle mass and proliferative and apoptotic myocytes. In the peripheral airways, heaves-affected horses had twice as much smooth muscle as control horses. Remodeling was associated with smooth muscle hyperplasia and in situ proliferation, without reduced apoptosis. Further antigenic exposure had no effect on the morphometric data. In central airways, proliferating myocytes were increased compared with control horses only after antigenic exposure. Peripheral airway smooth muscle mass is stable in chronically affected animals subjected to antigenic exposure. This increased mass is maintained in a dynamic equilibrium by an elevated cellular turnover, suggesting that targeting smooth muscle proliferation could be effective at decreasing chronic remodeling.

The Saudi Initiative for Asthma

The Saudi Initiative for Asthma (SINA) provides up-to-date guidelines for healthcare workers managing patients with asthma. SINA was developed by a panel of Saudi experts with respectable academic backgrounds and long-standing experience in the field. SINA is founded on the latest available evidence, local literature, and knowledge of the current setting in Saudi Arabia. Emphasis is placed on understanding the epidemiology, pathophysiology, medications, and clinical presentation. SINA elaborates on the development of patient-doctor partnership, self-management, and control of precipitating factors. Approaches to asthma treatment in SINA are based on disease control by the utilization of Asthma Control Test for the initiation and adjustment of asthma treatment. This guideline is established for the treatment of asthma in both children and adults, with special attention to children 5 years and younger. It is expected that the implementation of these guidelines for treating asthma will lead to better asthma control and decrease patient utilization of the health care system.