Older age and obesity are associated with increased airway closure in response to methacholine in patients with asthma

A Total Diet Replacement Weight Management Program for Difficult-to-Treat Asthma Associated With Obesity: A Randomized Controlled Feasibility Trial

BACKGROUND

Obesity is often associated with uncontrolled, difficult-to-treat asthma and increased morbidity and mortality. Previous studies suggest that weight loss may improve asthma outcomes, but with heterogenous asthma populations studied and unclear consensus on the optimal method of weight management. The Counterweight-Plus Programme (CWP) for weight management is an evidence-based, dietitian-led total diet replacement (TDR) program.

RESEARCH QUESTION

Can use of the CWP compared with usual care (UC) improve asthma control and quality of life in patients with difficult-to-treat asthma and obesity?

STUDY DESIGN AND METHODS

We conducted a 1:1 (CWP to UC) randomized, controlled single-center trial in adults with difficult-to-treat asthma and BMI of ≥ 30 kg/m2. The CWP was a 12-week TDR phase (800 kcal/d low-energy formula) followed by stepwise food reintroduction and weight loss maintenance for up to 1 year. The primary outcome was the change in Asthma Control Questionnaire 6 (ACQ6) score over 16 weeks. The secondary outcome was change in Asthma Quality of Life Questionnaire (AQLQ) score.

RESULTS

Thirty-five participants were randomized (36 screened) and 33 attended the 16-week follow-up (n = 17 in the CWP group, n = 16 in the UC group). Overall, mean ACQ6 score at baseline was 2.8 (95% CI, 2.4-3.1). Weight loss was greater in the CWP than UC group (mean difference, -12.1 kg; 95% CI, -16.9 to -7.4; P < .001). ACQ6 score improved more in the CWP than UC group (mean difference, -0.69; 95% CI, -1.37 to -0.01; P = .048). A larger proportion of participants achieved the minimal clinically important difference in ACQ6 score with CWP than with UC (53% vs 19%; P = .041; Number needed to treat, 3 [95% CI, 1.5-26.9]). AQLQ score improvement was greater in the CWP than UC group (mean difference, 0.76; 95% CI, 0.18-1.34; P = .013).

INTERPRETATION

Using a structured weight management program results in clinically important improvements in asthma control and quality of life over 16 weeks compared with UC in adults with difficult-to-treat asthma and obesity. This generalizable program is easy to deliver for this challenging phenotype. Longer-term outcomes continue to be studied.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03858608; URL: www.

CLINICALTRIALS

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From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity

This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.

Malat1 deficiency prevents hypoxia-induced lung dysfunction by protecting the access to alveoli

Hypoxia is common in lung diseases and a potent stimulator of the long non-coding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1). Herein, we investigated the impact of Malat1 on hypoxia-induced lung dysfunction in mice. Malat1-deficient mice and their wild-type littermates were tested after 8 days of normoxia or hypoxia (10% oxygen). Hypoxia decreased elastance of the lung by increasing lung volume and caused in vivo hyperresponsiveness to methacholine without altering the contraction of airway smooth muscle. Malat1 deficiency also modestly decreased lung elastance but only when tested at low lung volumes and without altering lung volume and airway smooth muscle contraction. The in vivo responsiveness to methacholine was also attenuated by Malat1 deficiency, at least when elastance, a readout sensitive to small airway closure, was used to assess the response. More impressively, in vivo hyperresponsiveness to methacholine caused by hypoxia was virtually absent in Malat1-deficient mice, especially when hysteresivity, a readout sensitive to small airway narrowing heterogeneity, was used to assess the response. Malat1 deficiency also increased the coefficient of oxygen extraction and decreased ventilation in conscious mice, suggesting improvements in gas exchange and in clinical signs of respiratory distress during natural breathing. Combined with a lower elastance at low lung volumes at baseline, as well as a decreased propensity for small airway closure and narrowing heterogeneity during a methacholine challenge, these findings represent compelling evidence suggesting that the lack of Malat1 protects the access to alveoli for air entering the lung.

Prophylactic Penehyclidine Inhalation for Prevention of Postoperative Pulmonary Complications in High-risk Patients: A Double-blind Randomized Trial

BACKGROUND

Postoperative pulmonary complications are common. Aging and respiratory disease provoke airway hyperresponsiveness, high-risk surgery induces diaphragmatic dysfunction, and general anesthesia contributes to atelectasis and peripheral airway injury. This study therefore tested the hypothesis that inhalation of penehyclidine, a long-acting muscarinic antagonist, reduces the incidence of pulmonary complications in high-risk patients over the initial 30 postoperative days.

METHODS

This single-center double-blind trial enrolled 864 patients age over 50 yr who were scheduled for major upper-abdominal or noncardiac thoracic surgery lasting 2 h or more and who had an Assess Respiratory Risk in Surgical Patients in Catalonia score of 45 or higher. The patients were randomly assigned to placebo or prophylactic penehyclidine inhalation from the night before surgery through postoperative day 2 at 12-h intervals. The primary outcome was the incidence of a composite of pulmonary complications within 30 postoperative days, including respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, and aspiration pneumonitis.

RESULTS

A total of 826 patients (mean age, 64 yr; 63% male) were included in the intention-to-treat analysis. A composite of pulmonary complications was less common in patients assigned to penehyclidine (18.9% [79 of 417]) than those receiving the placebo (26.4% [108 of 409]; relative risk, 0.72; 95% CI, 0.56 to 0.93; P = 0.010; number needed to treat, 13). Bronchospasm was less common in penehyclidine than placebo patients: 1.4% (6 of 417) versus 4.4% (18 of 409; relative risk, 0.327; 95% CI, 0.131 to 0.82; P = 0.011). None of the other individual pulmonary complications differed significantly. Peak airway pressures greater than 40 cm H2O were also less common in patients given penehyclidine: 1.9% (8 of 432) versus 4.9% (21 of 432; relative risk, 0.381; 95% CI, 0.171 to 0.85; P = 0.014). The incidence of other adverse events, including dry mouth and delirium, that were potentially related to penehyclidine inhalation did not differ between the groups.

CONCLUSIONS

In high-risk patients having major upper-abdominal or noncardiac thoracic surgery, prophylactic penehyclidine inhalation reduced the incidence of pulmonary complications without provoking complications.

EDITOR’S PERSPECTIVE

Obesity and Asthma

Obesity is a major risk factor for the development of asthma, and the prevalence of obesity is higher in people with asthma than in the general population. Obese people often have severe asthma-recent studies in the United States suggest that 60% of adults with severe asthma are obese. Multiple mechanisms link obesity and asthma, which are discussed in this article, and these pathways contribute to different phenotypes of asthma among people with obesity. From a practical aspect, changes in physiology and immune markers affect diagnosis and monitoring of disease activity in people with asthma and obesity. Obesity also affects response to asthma medications and is associated with an increased risk of co-morbidities such as gastroesophageal reflux disease, depression, and obstructive sleep apnea, all of which may affect asthma control. Obese people may be at elevated risk of exacerbations related to increased risk of severe disease in response to viral infections. Interventions that target improved dietary quality, exercise, and weight loss are likely to be particularly helpful for this patient population.

Obesity, Inflammation, and Severe Asthma: an Update

Purpose of Review

Obesity-associated difficult asthma continues to be a substantial problem and, despite a move to address treatable traits affecting asthma morbidity and mortality, it remains poorly understood with limited phenotype-specific treatments. The complex association between asthma, obesity, and inflammation is highlighted and recent advances in treatment options explored.

Recent Findings

Obesity negatively impacts asthma outcomes and has a causal link in the pathogenesis of adult-onset asthma. Imbalance in the adipose organ found in obesity favours a pro-inflammatory state both systemically and in airways. Obesity may impact currently available asthma biomarkers, and obesity-associated asthma specific biomarkers are needed. Whilst surgical weight loss interventions are associated with improvements in asthma control and quality of life, evidence for pragmatic conservative options are sparse. Innovative approaches tackling obesity-mediated airway inflammation may provide novel therapies.

Summary

The immunopathological mechanisms underlying obesity-associated asthma require further research that may lead to novel therapeutic options for this disease. However, weight loss appears to be effective in improving asthma in this cohort and focus is also needed on non-surgical treatments applicable in the real-world setting.

Functional significance of 8-isoprostanes in sinonasal disease and asthma

BACKGROUND

The purpose of this study was to investigate how 8-isoprostanes, used as a marker of airway oxidative stress, were related to sinus disease and asthma.

METHODS

We analyzed samples and data from two separate studies, one investigating sinonasal disease in asthma, the other investigating the effect of BMI on airway disease. We measured airway (nasal lavage) 8-isoprostanes and investigated the relationship with measures of sinus and asthma symptoms, asthma control and lung function.

RESULTS

The study of people with sinonasal disease and poorly controlled asthma included 48 obese, 31 overweight and 23 lean participants. In multivariate analysis, nasal lavage 8-isoprostane levels increased with increasing BMI (p < 0.01), and were higher in Caucasian than African American participants (p = 0.01). Sinus symptoms were inversely related to nasal 8-isoprostanes (p = 0.02) independent of BMI and Race. In the study investigating the effect of BMI on airway disease, we enrolled 13 controls with obesity and 21 people with obesity and asthma: 8-isoprostane levels were higher in obese controls than in obese people with asthma (p < 0.01), and levels were inversely related to sinus symptoms (p = 0.02) and asthma control (p < 0.01).

INTERPRETATION

8-isoprostanes in nasal lavage are increased in obesity, and increased in Caucasians compared with African Americans. However, levels are higher in obese controls than obese people with asthma, and appear inversely related to symptoms of airway disease.

CLINICAL IMPLICATION

Airway 8-isoprostanes likely reflect complex oxidative signaling pathways, which are altered in obesity and those of different race, rather than being a simple marker of airway oxidative injury.

CAPSULE SUMMARY

Increased airway oxidative signaling (8-isoprostanes), may reflect normal physiology in the setting of obesity, as decreased levels are associated with disease activity in people with chronic sinonasal disease and asthma.

Linggan Wuwei Jiangxin formula ameliorates airway hyperresponsiveness through suppression of IL-1β and IL-17A expression in allergic asthmatic mice especially with diet-induced obesity

Background

Obese asthma represents a disease phenotype, which is associated with worse disease control and unresponsiveness to standard anti-inflammatory regimens, including inhaled corticosteroids. Obesity-related innate airway hyperresponsiveness (AHR) plays a role in this asthma phenotype via activation of the IL-1β/innate lymphoid cell 3 (ILC3)/IL-17A pathway. Linggan Wuwei Jiangxin (LGWWJX) formula may be a promising therapeutic option for obese asthma according to traditional Chinese medicine theory, clinical experience and related research.

Methods

The murine model of allergic asthma with obesity was induced by ovalbumin (OVA) sensitization and challenge in combination with a high fat diet (HFD). LGWWJX formula intervention was oral administrated. AHR and bronchoalveolar lavage fluid (BALF) cellularity were measured. Lung and liver histopathology assessment was performed by haematoxylin and eosin (H&E) staining. IL-1β and IL-17A in BALF and serum were evaluated by ELISA. Additionally, the influence of different concentrations of LGWWJX formula on IL-1β stimulated IL-17A mRNA expression in ILC3 cells was evaluated in vitro.

Results

LGWWJX treatment significantly reduced AHR and allergic airway inflammatory responses in asthmatic mice, as measured by pulmonary histopathology and BALF cellularity, and these effects were more pronounced in obese asthmatic mice. While eosinophil infiltration in BALF was suppressed with LGWWJX treatment in non-obese asthmatic mice, neutrophils and basophils were significantly decreased in obese asthmatic mice. Notably, LGWWJX also demonstrated remarkable efficacy for weight loss and improvements in hepatic steatosis in mice fed with a HFD. Furthermore, the protein levels of IL-1β in both serum and BALF, as well as those of BALF IL-17A, declined with LGWWJX intervention in both obese and non-obese asthmatic mice, and results from ex-vivo experiments found that LGWWJX significantly attenuated the expression of IL-17A in ILC3 cells with or without stimulation by IL-1β.

Conclusions

LGWWJX may exert a protective effect on asthmatic individuals, especially those with concurrent obesity, most likely through mechanisms including the inhibition of the IL-1β/ILC3/IL-17A/AHR axis, anti-inflammatory effects, weight loss, and the regulation of lipid metabolism. This suggests a promising role of LGWWJX, alone or in combination with anti-inflammatory agents, for the treatment of obese asthma.

Airway closure is the predominant physiological mechanism of low ventilation seen on hyperpolarized helium-3 MRI lung scans

Hyperpolarized helium-3 MRI (³He MRI) provides detailed visualization of low- (hypo- and non-) ventilated lungs. Physiological measures of gas mixing may be assessed by multiple breath nitrogen washout (MBNW) and of airway closure by a forced oscillation technique (FOT). We hypothesize that in patients with asthma, areas of low-ventilated lung on ³He MRI are the result of airway closure. Ten control subjects, ten asthma subjects with normal spirometry (non-obstructed), and ten asthmatic subjects with reduced baseline lung function (obstructed) attended two testing sessions. On visit one, baseline plethysmography was performed followed by spirometry, MBNW, and FOT assessment pre and post methacholine challenge. On visit two, ³He MRI scans were conducted pre and post methacholine challenge. Post methacholine the volume of low-ventilated lung increased from 8.3% to 13.8% in the non-obstructed group (P = 0.012) and from 13.0% to 23.1% in the obstructed group (P = 0.001). For all subjects, the volume of low ventilation from ³He MRI correlated with a marker of airway closure in obstructive subjects, Xrs (6 Hz) and the marker of ventilation heterogeneity Scond with r² values of 0.61 (P < 0.001) and 0.56 (P < 0.001), respectively. The change in Xrs (6 Hz) correlated well (r² = 0.45, p < 0.001), whereas the change in Scond was largely independent of the change in low ventilation volume (r² = 0.13, P < 0.01). The only significant predictor of low ventilation volume from the multi-variate analysis was Xrs (6 Hz). This is consistent with the concept that regions of poor or absent ventilation seen on ³He MRI are primarily the result of airway closure.NEW & NOTEWORTHY This study introduces a novel technique of generating high-resolution 3D ventilation maps from hyperpolarized helium-3 MRI. It is the first study to demonstrate that regions of poor or absent ventilation seen on ³He MRI are primarily the result of airway closure.

Airway closing index in school-age children during exercise bronchoprovocation

OBJECTIVE

Airway Closing Index (ACI), the ratio of % change in FVC to % change in FEV₁ with bronchoprovocation, may represent changes in airflow due to airway closure, as opposed to airway narrowing. The objective of this study was to evaluate ACI during exercise bronchoprovocation (EB) in children.

METHODS

Children, 6 to 18 years of age, who underwent EB using a stationary bicycle ergometer over a 6-year period were reviewed. Pulmonary function, including ACI, in patients with a positive exercise challenge, defined as ≥10% decrease in FEV₁ following exercise, were compared to patients with a negative challenge.

RESULTS

A total of 1030 children with a median age of 13 (IQR 11-15) underwent EB, of which 376 (37%) had a positive exercise challenge. There was wide variability in ACI, with a median of 0.75 (0.28-1.21). Median ACI in those with a positive test was 0.68 (IQR 0.41-0.93) compared to 0.84 (IQR 0.09-1.06) for those with a negative test, p = 0.017. Median ACI was higher in older children (p < 0.001) and females (p < 0.0001). Median percent change in FEV₁ following bronchodilator for children in the highest quintile for ACI was 4.5 (IQR 1.3-8.1) compared to 5.5 (IQR 2-9.2) for children in the lowest quintile, p = 0.04.

CONCLUSIONS

There is wide variability in the ACI in children undergoing EB. ACI was lower in children with a positive challenge, the significance is unknown. Children with higher ACI may have increased airway closure with bronchoprovocation, and less response to bronchodilators.

Area Under the Expiratory Flow-Volume Curve (AEX): Assessing Bronchodilator Responsiveness

Background

Area under expiratory flow–volume curve (AEX) is a useful spirometric tool in stratifying respiratory impairment. The AEX approximations based on isovolumic flows can be used with reasonable accuracy when AEX is unavailable. We assessed here pre- to post-bronchodilator (BD) variability of AEX₄ as a functional assessment tool for lung disorders.

Methods

The BD response was assessed in 4330 subjects by changes in FEV₁, FVC, and AEX₄, which were derived from FVC, peak expiratory flow, and forced expiratory flow at 25%, 50%, and 75% FVC. Newly proposed BD response categories (negative, minimal, mild, moderate and marked) have been investigated in addition to standard criteria.

Results

Using standard BD criteria, 24% of subjects had a positive response. Using the new BD response categories, only 23% of subjects had a negative response; 45% minimal, 18% mild, 9% moderate, and 5% had a marked BD response. Mean percent change of the square root AEX₄ was 0.3% and 14.3% in the standard BD-negative and BD-positive response groups, respectively. In the new BD response categories of negative, minimal, mild, moderate, and marked, mean percent change of square root AEX₄ was − 8.2%, 2.9%, 9.2%, 15.0%, and 24.8%, respectively.

Conclusions

Mean pre- to post-BD variability of AEX₄ was < 6% and stratified well between newly proposed categories of BD response (negative, minimal, mild, moderate and marked). We suggest that AEX₄ (AEX) could become a useful measurement for stratifying dysfunction in obstructive lung disease and invite further investigation into indications for using bronchodilator agents or disease-modifying, anti-inflammatory therapies.

Comorbidity and polypharmacy in patients with breast cancer

BACKGROUND

Cancer sufferers are aged ≥ 65 years, but research has focused infrequently on elderly patients with the majority of cancer. We aimed not only to determine the frequency of comorbidity and polypharmacy, but also to present the discrepiancies in elderly versus non-elderly patients with breast cancer.

METHODS

A total of 352 female patients aged over 18 years, 252 non-elderly and 100 elderly, followed-up in the oncology department of a tertiary hospital between January 2016 and September 2019 were retrospectively screened. Demographic data, comorbidity and medications of the patients were recorded hospital data processing system. Polypharmacy was defined as the use of ≥ 5 different medications.

RESULTS

The most common four chronic diseases in both non-elderly and elderly groups were muscle-joint-bone disease, gastrointestinal diseases, diabetes mellitus and hypertension. The most common four prescribed drugs were NSAID, adjuvant endocrine therapy, PPI, and vitamin D or/and calcium in non-elderly group while those were ACEI-ARB, PPI, NSAID, and diuretics in elderly one. The frequency of polypharmacy was 50% (n = 126) in the non-elderly patients and 74% (n = 74) in the elderly ones. These were considered statistically significant (p < 0.001). The mean number of prescription medication categories reported was 5.02 (SD = 2.90; range 0-14) in non-elderly group whereas those was 6.83 (SD = 3.18; range 0-15) in elderly one (p < 0.001). The mean of ages were 47.9 years (without polypharmacy) and 51.3 years (with polypharmacy) in non-elderly patients while those are, respectively, 70.9 years and 74.7 years in elderly ones. These were considered statistically significant (respectively; p = 0.006, p = 0.009).

CONCLUSIONS

We first gained to raise awareness in the literature of comorbidity and polypharmacy in patients with breast cancer and to compare between the elderly and non-elderly participants. For the effectiveness of cancer treatment, importance in geriatric population, attention to drug-drug interaction, such studies should be considered during clinical practice.

The Effects of Obesity in Asthma

PURPOSE OF REVIEW

Rising costs and increasing morbidity makes the identification and treatment of high-risk asthma phenotypes important. In this review, we outline the complex relationship between obesity and asthma.

RECENT FINDINGS

Studies have confirmed a bi-directional relationship between obesity and asthma. Pathophysiological factors implicated include genetic risk, the effect of diet and microbiome, and obesity-related cytokines. There have been robust, albeit derived, efforts to phenotype this group with distinct clinical presentations based on age of onset of asthma. Unfortunately, the poor performance of biomarkers and traditional lung function testing has impeded diagnosis, phenotyping, and management of the obese asthma patient. There is also a lack of targeted interventions with weight loss showing some benefits. Obesity increases the prevalence of asthma and is associated with worse outcomes. There are unique research and clinical challenges while managing this group of patients.