Determinants of peripheral airway function in adults with and without asthma

Intestinal microbiota and probiotic intervention in children with bronchial asthma

Objective

This study aims to understand the differences in intestinal flora, expression of helper T cells, allergy-related indicators, and cytokine levels between children with bronchial asthma and healthy children. The study seeks to clarify the effectiveness and safety of probiotic preparations in the treatment of bronchial asthma in children, and to provide new methods for the treatment of bronchial asthma.

Methods

A total of 66 pediatric patients aged 3-6 years with bronchial asthma and 35 healthy children undergoing physical examination during the same period were enrolled, designated as the asthma group and the healthy group, respectively. The asthma group was further divided into the probiotic group and the non-probiotic group based on whether probiotics were used. The gut microbiota, serum IgE antibody levels, cytokines (IL-4, IL-5, IL-9, IL-13 levels), proportions of helper T cells (Th1, Th2), and hypersensitive C-reactive protein were measured and compared among the groups.

Results

Children with bronchial asthma had decreased abundance and reduced diversity of intestinal flora compared to the healthy group. At the genus level, the asthma group showed increased abundance of Bacteroides and decreased abundance of Faecalibacterium and Veillonella; The probiotic group demonstrated a significantly higher improvement in the abundance of these genera before and after treatment compared to the non-probiotic group (P < 0.05). Compared to the healthy group, children with asthma had elevated levels of serum IgE, IL-4, IL-5, IL-9, and IL-13, as well as a decreased Th1/Th2 ratio, all of which showed statistical differences (P < 0.05). After treatment, all immune indicators improved. Specifically, the probiotic group exhibited a more significant decrease in serum IgE, IL-4, and IL-13 levels compared to the non-probiotic group (P < 0.05).

Conclusion

Children with bronchial asthma exhibit dysbiosis of intestinal flora, characterized by an increased abundance of the Bacteroides and decreased abundance of the Faecalibacterium and Veillonella. This imbalance in intestinal flora increases the risk of allergic diseases. Probiotics can effectively improve dysbiosis of intestinal flora, contributing to the balance of immune function in children, and can be used as an adjunct therapy for the treatment of bronchial asthma.

Beyond forced exhalation: impulse oscillometry as a promising tool for bronchial hyperresponsiveness evaluation

Introduction: The multiple forced expiratory maneuvers that must be performed during methacholine test require a high degree of collaboration and can lead to fatigue. However, impulse oscillometry (IOS) is a noninvasive test, quick and easy to perform, that does not require effort-dependent maneuvers. Objectives: The primary endpoint was to evaluate the relationship between IOS and spirometry during the methacholine test. The secondary endpoint was to study the predictive value of baseline IOS in the development of bronchial hyperreactivity. Methods: Observational, prospective, cross-sectional study, with recruitment of consecutive patients from the pulmonology department with clinical suspicion of bronchial asthma with negative bronchodilator test and normal FeNO. Results: Twenty-five patients were included, with a mean age of 49 ± 18 years. Thirteen patients (52%) had a positive methacholine test. The correlation between IOS indices and FEV1 was significant (p < 0.05) in all cases. The indices with the highest predictive power were R5-20 and AX. The optimal cutoff points were an increase of greater than 32.96% in R5, greater than 120.83% for X5, an increase of 30.30 [kPa l-1s-1] in R5-20, and an increase of 1.01 [kPa l-1] for AX. Baseline oscillometry demonstrated a strong predictive value in the development of bronchial hyperreactivity, with a sensitivity of 61.5% and a specificity of 91.7%, using the cut-off point of 160.0% for R5. Conclusions: IOS may be a valuable alternative to forced spirometry in detecting bronchial hyperreactivity during the methacholine test, showing a good correlation between both tests.

Impulse oscillometry and its independent role in the diagnosis of chronic obstructive pulmonary disease

Background

Pulmonary function test, particularly in patients with COVID-19, is problematic because it involves forced expiration. Impulse oscillometry (IOS) reduces the potential exposure of health-care staff to infectious droplets. In this study, we investigated the correlation between IOS and spirometry and whether IOS can precisely predict spirometry-based diagnoses of chronic obstructive pulmonary disease (COPD).

Methods

We retrospectively analyzed the data (January 1 to December 31, 2021) of patients who underwent both spirometry and IOS on the same date. One-way analysis of variance was performed to evaluate the IOS results of patients stratified into two (COPD and non-COPD) groups by spirometry results. IOS results were also analyzed using receiver operator characteristics curves to diagnose advanced COPD, which was indicated by a postbronchodilator (BD) forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio of <0.6. We further evaluated the accuracy of oscillometry as a predictor of spirometry-based COPD diagnosis.

Results

A total of 115 patients were included in the analysis. The best parameters assessed for spirometry-based COPD diagnosis were area under reactance (AX) and airway resistance (predicted R5% × resonant frequency) in relation to body mass index (BMI). However, when the post-BD FEV1/FVC ratio was <0.6, BMI-adjusted airway resistance had an area under curve (0.782; 95 % confidence interval: 0.620-0.945) value larger than the corresponding AX. A BMI-adjusted airway resistance value of >160 moderately predicted spirometry-based COPD diagnosis.

Conclusions

BMI-adjusted airway resistance is a potential predictor of spirometry-based COPD diagnosis; the cutoff values of this parameter differ between individuals with and without obesity.

D-ROMs and PAT Tests Reveal a High Level of Oxidative Stress in Patients with Severe Well-Controlled Asthma, and D-ROMs Are Positively Correlated with R20 Values That Indicate Approximate Central Airway Resistance

BACKGROUND

The derivatives-reactive oxygen metabolites (d-ROMs) and plasma antioxidant capacity (PAT) tests are oxidative indexes. Severe asthma has been related to oxidative stress. We aimed to investigate d-ROMs and PAT values in severely controlled asthmatics and the correlation of these values with lung function.

METHODS

Blood samples were collected from severely controlled asthmatics and centrifuged at 3000 rpm for 10 min. The supernatant was collected. The assays were performed within three hours of collection. The fraction of exhaled nitric oxide (FeNO), impulse oscillometry (IOS), and spirometry were determined. Symptom control was recorded using the asthma control test (ACT).

RESULTS

Approximately 40 patients with severe controlled asthma (75%: women), mean age of 62 ± 12 years, were recruited. Approximately 5% had obstructive spirometry. The IOS revealed airway abnormalities even though the spirometric results were within the normal range, with it being more sensitive than spirometry. The D-ROMs and PAT test values were higher than normal, indicating oxidative stress in severe asthmatics with controlled asthma. D-ROMs were positively correlated with R20 values, indicating central airway resistance.

CONCLUSIONS

The IOS technique revealed an otherwise hidden airway obstruction with spirometry. The D-ROMs and PAT tests revealed a high level of oxidative stress in severe controlled asthmatics. D-ROMs correlate with R20, indicating central airway resistance.

Lifetime cannabis exposure and small airway function in a population-based cohort study

Background and objective

The long-term effects of cannabis on small airway function remain unclear. We investigated associations between cannabis use and small airway function in a general population sample.

Methods

Cannabis use was ascertained at multiple ages from age 18 to 45 years and quantified as joint-years among 895 participants in the Dunedin Multidisciplinary Health and Development Study. Small airway function at ages 38 and 45 years was measured using impulse oscillometry (IOS) before and after inhalation of salbutamol. Analyses used multiple linear regression adjusting for tobacco use, body mass index and height. Longitudinal analyses of cannabis use between 38 and 45 years also adjusted for IOS at age 38 years.

Results

Associations between lifetime cannabis joint-years and IOS differed between men and women: in women, cannabis use was associated with pre-bronchodilator resistance at 5 Hz (R 5) and 20 Hz (R 20), reactance at 5 Hz, area of reactance and resonant frequency, and marginally associated with the difference between R 5 and R 20. Cannabis use was only statistically significantly associated with pre-bronchodilator resonant frequency in men. Cannabis use between the ages of 38 and 45 years was associated with a similar pattern of changes in IOS measures. After salbutamol, cannabis use was only statistically significantly associated with R 5 and R 20 among women and none of the IOS measures among men.

Conclusions

Cannabis use is associated with small airway dysfunction at age 45 years, indicating an increase in peripheral airway resistance and reactance. These associations were greater and mostly only statistically significant among women. Associations were weaker and mostly nonsignificant after bronchodilator use, suggesting that cannabis-induced changes in small airways may be at least partially reversible.

Causal Effects of Body Mass Index on Airflow Obstruction and Forced Mid-Expiratory Flow: A Mendelian Randomization Study Taking Interactions and Age-Specific Instruments Into Consideration Toward a Life Course Perspective

Obesity has complex links to respiratory health. Mendelian randomization (MR) enables assessment of causality of body mass index (BMI) effects on airflow obstruction and mid-expiratory flow. In the adult SAPALDIA cohort, recruiting 9,651 population-representative samples aged 18–60 years at baseline (female 51%), BMI and the ratio of forced expiratory volume in 1 second (FEV₁) to forced vital capacity (FVC) as well as forced mid-expiratory flow (FEF25–75%) were measured three times over 20 follow-up years. The causal effects of BMI in childhood and adulthood on FEV1/FVC and FEF25–75% were assessed in predictive (BMI averaged over 1st and 2nd, lung function (LF) averaged over 2nd and 3rd follow-up; N = 2,850) and long-term cross-sectional models (BMI and LF averaged over all follow-ups; N = 2,728) by Mendelian Randomization analyses with the use of weighted BMI allele score as an instrument variable and two-stage least squares (2SLS) method. Three different BMI allele scores were applied to specifically capture the part of BMI in adulthood that likely reflects tracking of genetically determined BMI in childhood. The main causal effects were derived from models containing BMI (instrumented by BMI genetic score), age, sex, height, and packyears smoked as covariates. BMI interactions were instrumented by the product of the instrument (BMI genetic score) and the relevant concomitant variable. Causal effects of BMI on FEV1/FVC and FEF25–75% were observed in both the predictive and long-term cross-sectional models. The causal BMI- LF effects were negative and attenuated with increasing age, and stronger if instrumented by gene scores associated with childhood BMI. This non-standard MR approach interrogating causal effects of multiplicative interaction suggests that the genetically rooted part of BMI patterns in childhood may be of particular relevance for the level of small airway function and airflow obstruction later in life. The methodological relevance of the results is first to point to the importance of a life course perspective in studies on the etiological role of BMI in respiratory health, and second to point out novel methodological aspects to be considered in future MR studies on the causal effects of obesity related phenotypes.

Cannabis use disorder and the lungs

Cannabis is one of the world's most widely used recreational drugs and the second most commonly smoked substance. Research on cannabis and the lungs has been limited by its illegal status, the variability in strength and size of cannabis cigarettes (joints), and the fact that most cannabis users also smoke tobacco, making the effects difficult to separate. Despite these difficulties, the available evidence indicates that smoking cannabis causes bronchitis and is associated with changes in lung function. The pattern of effects is surprisingly different from that of tobacco. Whereas smoking cannabis appears to increase the risk of severe bronchitis at quite low exposure, there is no convincing evidence that this leads to chronic obstructive pulmonary disease. Instead, cannabis use is associated with increased central airway resistance, lung hyperinflation and higher vital capacity with little evidence of airflow obstruction or impairment of gas transfer. There are numerous reports of severe bullous lung disease and pneumothorax among heavy cannabis users, but convincing epidemiological data of an increased risk of emphysema or alveolar destruction are lacking. An association between cannabis and lung cancer remains unproven, with studies providing conflicting findings.

Airway Oscillometry Detects Spirometric-Silent Episodes of Acute Cellular Rejection

Rationale: Acute cellular rejection (ACR) is common during the initial 3 months after lung transplant. Patients are monitored with spirometry and routine surveillance transbronchial biopsies. However, many centers monitor patients with spirometry only because of the risks and insensitivity of transbronchial biopsy for detecting ACR. Airway oscillometry is a lung function test that detects peripheral airway inhomogeneity with greater sensitivity than spirometry. Little is known about the role of oscillometry in patient monitoring after a transplant.Objectives: To characterize oscillometry measurements in biopsy-proven clinically significant (grade ≥2 ACR) in the first 3 months after a transplant.Methods: We enrolled 156 of the 209 double lung transplant recipients between December 2017 and March 2019. Weekly outpatient oscillometry and spirometry and surveillance biopsies at Weeks 6 and 12 were conducted at our center.Measurements and Main Results: Of the 138 patients followed for 3 or more months, 15 patients had 16 episodes of grade 2 ACR (AR2) and 44 patients had 64 episodes of grade 0 ACR (AR0) rejection associated with stable and/or improving spirometry. In 15/16 episodes of AR2, spirometry was stable or improving in the weeks leading to transbronchial biopsy. However, oscillometry was markedly abnormal and significantly different from AR0 (P < 0.05), particularly in integrated area of reactance and the resistance between 5 and 19 Hz, the indices of peripheral airway obstruction. By 2 weeks after biopsy, after treatment for AR2, oscillometry in the AR2 group improved and was similar to the AR0 group.Conclusions: Oscillometry identified physiological changes associated with AR2 that were not discernible by spirometry and is useful for graft monitoring after a lung transplant.

Systematic Assessment of Difficult-to-Treat Asthma: Principles and Perspectives

Difficult-to-treat asthma affects a minority of adults and children with asthma but represents a challenging mix of misdiagnosis, multimorbidity, inadequate self-management, severe airway pathobiology, and treatment complications. Management of these patients extends beyond asthma pharmacotherapy, because multiple other patient-related domains need to be addressed as well. Such complexity can hinder adequate clinical assessment even when performed in specialist practice. Systematic assessment undertaken by specialized multidisciplinary teams brings a broad range of resources to bear on patients with difficult-to-treat asthma. Although the concept of systematic assessment is not new, practices vary considerably and implementation is not universal. Nevertheless, assessment protocols are already in place in several institutions worldwide, and outcomes after such assessments have been highly encouraging. This review discusses the rationale, components, and benefits of systematic assessment, outlining its clinical utility and the available evidence for improved outcomes. It describes a range of service configurations and assessment approaches, drawing examples from severe asthma centers around the world to highlight common essential elements. It also provides a framework for establishing such services and discusses practical considerations for implementation.

Linking COPD epidemiology with pediatric asthma care: Implications for the patient and the physician

What are the implications of a lower than expected forced expiratory volume in one second (FEV1) in childhood on respiratory health later in adulthood? Lung function is known to track with age, and there is evidence from recent epidemiologic studies that impaired lung function early in life is associated with later chronic airflow limitation, or even chronic obstructive pulmonary disease, COPD. This risk seems particularly strong in subjects with persistent and severe forms of childhood asthma. Can we translate findings from longitudinal cohort studies to individual risk predictions and preventive guidelines in our pediatric care? In this review, we discuss the clinical implementations of recent epidemiological respiratory studies and the importance of preserved lung health across the life course. Also, we evaluate available clinical tools, primarily lung function measures, and profiles of risk factors, including biomarkers, that may help identifying children at risk of chronic airway disease in adulthood. We conclude that translating population level results to the individual patient in the pediatric care setting is not straight forward, and that there is a need for studies specifically designed to evaluate performance of prediction of risk profiles for long-term sequelae of childhood asthma and lung function impairment.

Cannabis-Associated Asthma and Allergies

Inhalation of cannabis smoke is its most common use and the pulmonary complications of its use may be the single most common form of drug-induced pulmonary disease worldwide. However, the role of cannabis consumption in asthma patients and allergic clinical situations still remains controversial. To review the evidence of asthma and allergic diseases associated with the use of marijuana, we conducted a search of English, Spanish, and Portuguese medical using the search terms asthma, allergy, marijuana, marihuana, and cannabis. Entries made between January 1970 and March 2017 were retrieved. Several papers have shown the relationship between marijuana use and increase in asthma and other allergic diseases symptoms, as well as the increased frequency of medical visits. This narrative review emphasizes the importance to consider cannabis as a precipitating factor for acute asthma and allergic attacks in clinical practice. Although smoking of marijuana may cause respiratory symptoms, there is a need for more studies to elucidate many aspects in allergic asthma patients, especially considering the long-term use of the drug. These patients should avoid using marijuana and be oriented about individual health risks, possible dangers of second-hand smoke exposure, underage use, safe storage, and the over smoking of marijuana.

Distinctive lung function trajectories from age 10 to 26 years in men and women and associated early life risk factors - a birth cohort study

Pre-bronchodilator lung function including forced vital capacity (FVC), forced expiratory flow in 1 second (FEV1), their ratio (FEV1/FVC), and forced expiratory flow 25-75% (FEF25-75) measured at age 10, 18, and 26 years in the Isle of Wight birth cohort was analyzed for developmental patterns (trajectories). Early life risk factors before the age of 10 years were assessed for the trajectories.

METHOD

Members of the birth cohort (1989/90) were followed at age 1, 2, 4, 10, 18, and 26 years. Allergic sensitization and questionnaire data were collected. Spirometry tests were performed and evaluated according to the American Thoracic Society (ATS) criteria at 10, 18, and 26 years. To identify developmental trajectories for FVC, FEV1, FEV1/FVC, and FEF25-75 from 10 to 26 years, a finite mixture model was applied to the longitudinal lung function data, separately for males and females. Associations of early life factors with the respective lung function trajectories were assessed using log-linear and logistic regression analyses.

RESULTS

Both high and low lung function trajectories were observed in men and women. FVC continued to grow beyond 18 years in men and women, whereas FEV1 peaked at age 18 years in female trajectories and in one male trajectory. For the FEV1/FVC ratios and FEF25-75 most trajectories appeared highest at age 18 and declined thereafter. However, the low FEV1/FVC trajectory in both sexes showed an early decline at 10 years. Lower birth weight was linked with lower lung function trajectories in males and females. Eczema in the first year of life was a risk factor for later lung function deficits in females, whereas the occurrence of asthma at 4 years of age was a risk factor for later lung function deficits in males. A positive skin prick test at age four was a risk for the low FEV1 trajectory in females and for the low FEV1/FVC trajectory in males.

CONCLUSION

Men and women showed distinctive lung function trajectories and associated risk factors. Lower lung function trajectories can be explained by not achieving maximally attainable function at age 18 years and by a function decline from 18 to 26 years.

Associations between lung and endothelial function in early middle age

BACKGROUND AND OBJECTIVE

Chronic lung disease is associated with impaired endothelial function and this may be a risk factor for poor cardiovascular health. It is unknown if there is an association between lung and endothelial function in the general population. We investigated associations between lung and endothelial function in a population-based cohort of 38-year-old men and women.

METHODS

Systemic endothelial function was measured using peripheral arterial tonometry to calculate the Framingham reactive hyperaemia index. Lung function was assessed using spirometry, plethysmographic lung volumes, airway conductance and gas transfer. Associations between lung and endothelial function were assessed with and without adjustment for potential confounding factors using regression analyses.

RESULTS

Sex modified the association between lung and endothelial function. Among women, lower values of pre- and post-bronchodilator spirometry, total lung capacity and functional residual capacity (FRC) were associated with worse endothelial function (P < 0.05). These associations persisted after adjustment for smoking, asthma diagnoses, fitness and body mass index. Associations were weaker among men: only FRC, airway conductance and post-bronchodilator forced expiratory volume in 1 s (FEV₁ )/forced vital capacity (FVC) ratios were associated with endothelial function. Endothelial function was not associated with gas transfer in either sex.

CONCLUSION

Lower lung volumes and airflow obstruction are associated with endothelial dysfunction among women. There is weaker evidence for an association between airway and endothelial function in men. These findings may partly explain the increased risk of cardiovascular disease among people with poor lung function, but suggest that there are sex differences in this association.

Passive smoking induces pediatric asthma by affecting the balance of Treg/Th17 cells

BACKGROUND

We aimed to explore the effects of passive smoking on the severity of pediatric asthma and associated molecular mechanisms.

METHODS

A total of 378 children with asthma were assigned into four groups according to asthma severity (from grades I to IV). Univariate and multivariate regression analyses were used to analyze possible factors associated with asthma severity in children. Environmental tobacco smoke (ETS) exposure was measured via cotinine concentration in urine. Serum levels of immunoglobulin E (IgE) and cytokines were measured using allergen diagnostic and ELISA (enzyme-linked immunosorbent assay) kits. The percentage of T-regulatory (Treg) and T-helper type 17 (Th17) cells in peripheral blood mononuclear cells (PMBCs) were measured by flow cytometry. Treg- and Th17-associated transcription factors from PMBCs were measured by using ELISA kits.

RESULTS

The levels of ETS and serum IgE, and the duration and amounts of passive smoking were closely associated with asthma severity. Passive smoking significantly reduced the levels of FoxP3 (Forkhead/winged helix transcription factor) and tumor growth factor-β, which were associated with Treg cells, and increased the levels of interleukin-17A and interleukin-23, which were associated with Th17 cells. Meanwhile, passive smoking significantly reduced the ratio of Treg/Th17 cells (P < 0.05).

CONCLUSIONS

Passive smoking was closely associated with the severity of childhood asthma by affecting the balance of Treg/Th17 cells.

A longitudinal study of cannabis use increasing the use of asthma medication in young Norwegian adults

Background

A small number of studies have shown that the use of cannabis increases the risk of bronchial asthma. There is, however, a paucity of longitudinal studies which are able to control for known risk factors of bronchial asthma.

Methods

Survey data from a population-based longitudinal study encompassing 2602 young adults followed for 13 years were coupled with individual prescription data on asthma medication (β₂-adrenergic receptor agonists and glucocorticoids for inhalation) from the Norwegian national prescription database, which covers the entire Norwegian population. Current cannabis use, gender, age, years of education, body mass index (BMI; kg/m²) and current smoking were measured.

Results

Prescription of asthma medication was associated with female gender, self-reported earlier asthma and allergies, daily tobacco smoking and current cannabis use. In a model adjusting for gender, age, years of education, BMI, earlier self-reported asthma and allergies and current tobacco smoking the odds ratio for a current cannabis user to fill prescriptions for asthma medication was 1.71 (95% CI: 1.06–2.77; p = 0.028).

Conclusions

This suggests that cannabis is a risk factor for bronchial asthma or use of asthma medication even when known risk factors are taken into consideration. Intake of cannabis through smoking should be avoided in persons at risk.

Impedance Oscillometry: Emerging Role in the Management of Chronic Respiratory Disease

PURPOSE OF REVIEW

Chronic respiratory diseases affecting adults and children are widely prevalent, so lung function testing is imperative for diagnosis and management. Spirometry is the traditional standard measure of lung function; however, certain groups of patients are unable to provide accurate and reproducible exhalation maneuvers. Consequently, the impedance oscillometry system (IOS) has been developed as an effort, independent technique to assess airway function in children and the elderly. To better understand this emerging modality, the following review will compare IOS with spirometry, examine the function of the device, provide interpretation strategies, and discuss the evidence supporting its use in adults and children with chronic lung disease.

RECENT FINDINGS

In a population of symptomatic adults with suspected COPD, impedance oscillometry resistance measurements correlate with FEV₁ and lung resistance increases with the severity of airflow limitation. In patients with asthma, IOS is a sensitive measure of airway hyperresponsiveness and bronchodilator response. Impedance oscillometry is evolving as an alternative measure to assess lung function pediatric and adult populations.