Obesity and Asthma

Eosinophil biology from the standpoint of metabolism: implications for metabolic disorders and asthma

Eosinophils, recognized for their immune and remodeling functions and participation in allergic inflammation, have recently garnered attention due to their impact on host metabolism, especially in the regulation of adipose tissue. Eosinophils are now known for their role in adipocyte beiging, adipokine secretion, and adipose tissue inflammation. This intricate interaction involves complex immune and metabolic processes, carrying significant implications for systemic metabolic health. Importantly, the interplay between eosinophils and adipocytes is bidirectional, revealing the dynamic nature of the immune-metabolic axis in adipose tissue. While the homeostatic regulatory role of eosinophils in adipose tissue is appreciated, this relationship in the context of obesity or allergic inflammation is much less understood. Mechanistic details of eosinophil-adipose interactions, especially the direct regulation of adipocytes by eosinophils, are also lacking. Another poorly understood aspect is the metabolism of the eosinophils themselves, encompassing metabolic shifts during eosinophil subset transitions in different tissue microenvironments, along with potential effects of host metabolism on the programming of eosinophil hematopoiesis and the resulting plasticity. This review consolidates recent research in this emerging and fascinating frontier of eosinophil investigation, identifying unexplored areas and presenting innovative perspectives on eosinophil biology in the context of metabolic disorders and associated health conditions, including asthma.

Understanding the determinants of self-reported asthma in Turkey: insights from national data on individual, lifestyle, socioeconomic, and healthcare access factors

Asthma, influenced by genetic, environmental, and social factors is leading to poor outcomes and preventable mortality due to inadequate care and limited access to effective treatments. This study aimed to analyze self-reported asthma prevalence in Turkey, focusing on its determinants, such as individual factors, lifestyle, socioeconomic status, and healthcare access.This study conducts a secondary analysis of the 2019 Turkiye Health Survey (THS), employing a nationally representative cross-sectional design by the Turkish Statistical Institute. The sampling utilized a stratified, two-stage cluster sampling method, with data from 16,976 adults (aged 15 years and older) analyzed for asthma determinants. The independent variables are categorized into four domains: individual factors, lifestyle assessment, socioeconomic factors, and access to the healthcare services.The prevalence of asthma is 9.8%, varying significantly across demographics. Higher asthma rates are observed among older, divorced/widowed individuals, those with communication difficulties, and obese individuals. Cost-related unmet healthcare needs and appointment scheduling delays increase asthma risk. Logistic regression models identified age, marital status, obesity, education level, and healthcare access as significant predictors of asthma.This study underscores the multifaceted determinants of asthma in Turkey, highlighting the necessity for targeted interventions addressing individual, lifestyle, socioeconomic, and healthcare access factors.

An Adipo-Pulmonary Axis Mediated by FABP4 Hormone Defines a Therapeutic Target Against Obesity-Induced Airway Disease

Obesity-related airway disease is a clinical condition without a clear description and effective treatment. Here, we define this pathology and its unique properties, which differ from classic asthma phenotypes, and identify a novel adipo-pulmonary axis mediated by FABP4 hormone as a critical mediator of obesity-induced airway disease. Through detailed analysis of murine models and human samples, we elucidate the dysregulated lipid metabolism and immunometabolic responses within obese lungs, particularly highlighting the stress response activation and downregulation of surfactant-related genes, notably SftpC. We demonstrate that FABP4 deficiency mitigates these alterations, demonstrating a key role in obesity-induced airway disease pathogenesis. Importantly, we identify adipose tissue as the source of FABP4 hormone in the bronchoalveolar space and describe strong regulation in the context of human obesity, particularly among women. Finally, our exploration of antibody-mediated targeting of circulating FABP4 unveils a novel therapeutic avenue, addressing a pressing unmet need in managing obesity-related airway disease. These findings not only define the presence of a critical adipo-pulmonary endocrine link but also present FABP4 as a therapeutic target for managing this unique airway disease that we refer to as fatty lung disease associated with obesity.

One Sentence Summary

Investigating FABP4's pivotal role in obesity-driven airway disease, this study unveils an adipo-pulmonary axis with potential therapeutic implications.

U-shaped association between 25-hydroxyvitamin D concentration and the prevalence of asthma in the overweight and obese U.S. population

INTRODUCTION

Vitamin D supplementation has shown promise in averting asthma. However, the association between 25(OH)D levels and asthma prevention in various demographic groups remains inconclusive. Here, we explore this relationship in the context of overweight and obese individuals in the United States.

METHODS

We scrutinized cross-sectional data derived from the National Health and Nutrition Examination Survey conducted between 2007 and 2018. This dataset encompasses comprehensive information about asthma patients with a body mass index greater than 25 kg/m2, in addition to data regarding 25(OH)D concentration and other pertinent variables. Among the 3889 participants, 16.2% (631/3889) reported a history of asthma, constituting 1765 (45.4%) males and 2124 (54.6%) females. The median age was 56.0 years, with a standard deviation of 16.0 years. We conducted restricted cubic spline (RCS) regression analysis to assess the correlation between 25(OH)D levels and asthma.

RESULTS

After adjusting for confounders, compared to individuals with lower 25-hydroxyvitamin D concentration (group1 ≤ 46.6 nmol/L), the adjusted odds ratios (OR) for asthma in group2 (46.7-62 nmol/L), group3 (62.1-78.2 nmol/L), and group4 (≥78.3 nmol/L) were 0.68 (95% CI: 0.49-0.94, p < 0.021), 0.65 (95% CI: 0.47-0.88, p < 0.006), and 0.83 (95% CI: 0.61-1.12, p < 0.22), respectively. Restricted cubic spline (RCS) regression analysis revealed a nonlinear U-shaped curve (p = 0.017) with an inflection point at approximately 84.95 nmol/L.

CONCLUSIONS

High levels of 25(OH)D are correlated with a diminished prevalence of asthma among overweight and obese individuals in the United States.

AMPK Regulates M1 Macrophage Polarization through the JAK2/STAT3 Signaling Pathway to Attenuate Airway Inflammation in Obesity-Related Asthma

Abstract-Obesity-related asthma is primarily characterized by nonallergic inflammation, with pathogenesis involving oxidative stress, metabolic imbalance, and immunoinflammatory mechanisms. M1 macrophages, which predominantly secrete pro-inflammatory factors, mediate insulin resistance and systemic metabolic inflammation in obese individuals. Concurrently, adenosine monophosphate-activated protein kinase (AMPK) serves as a critical regulator of intracellular energy metabolism and is closely associated with macrophage activation. However, their specific roles and associated mechanisms in obesity-related asthma remain to be explored. In this study, we investigated the macrophage polarization status and potential interventional mechanisms through obesity-related asthmatic models and lipopolysaccharide (LPS) -treated RAW264.7 cell with a comprehensive series of evaluations, including HE, PAS and Masson staining of lung histopathology, immunohistochemical staining, immunofluorescence technology, qRT-PCR, Western Blot, and ELISA inflammatory factor analysis. The results revealed M1 macrophage polarization in obesity-related asthmatic lung tissue alongside downregulation of AMPK expression. Under LPS stimulation, exogenous AMPK activation attenuated M1 macrophage polarization via the Janus kinase 2/ signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Additionally, in obesity-related asthmatic mice, AMPK activation was found to alleviate airway inflammation by regulating M1 macrophage polarization, the mechanism closely associated with the JAK2/STAT3 pathway. These findings not only advance our understanding of macrophage polarization in obesity-related asthma, but also provide new therapeutic targets for its treatment.

Association of Obesity and Severe Asthma in Adults

The incidence of obesity and asthma continues to enhance, significantly impacting global public health. Adipose tissue is an organ that secretes hormones and cytokines, causes meta-inflammation, and contributes to the intensification of bronchial hyperreactivity, oxidative stress, and consequently affects the different phenotypes of asthma in obese people. As body weight increases, the risk of severe asthma increases, as well as more frequent exacerbations requiring the use of glucocorticoids and hospitalization, which consequently leads to a deterioration of the quality of life. This review discusses the relationship between obesity and severe asthma, the underlying molecular mechanisms, changes in respiratory function tests in obese people, its impact on the occurrence of comorbidities, and consequently, a different response to conventional asthma treatment. The article also reviews research on possible future therapies for severe asthma. The manuscript is a narrative review of clinical trials in severe asthma and comorbid obesity. The articles were found in the PubMed database using the keywords asthma and obesity. Studies on severe asthma were then selected for inclusion in the article. The sections: 'The classification connected with asthma and obesity', 'Obesity-related changes in pulmonary functional tests', and 'Obesity and inflammation', include studies on subjects without asthma or non-severe asthma, which, according to the authors, familiarize the reader with the pathophysiology of obesity-related asthma.

The relationships between Physical activity and asthma control and Body Mass Index (BMI) in patients with asthma

OBJECTIVE

Asthma is one of the most common chronic conditions in developed countries. We examined whether physical activity (PA) is related to asthma control and body mass index (BMI) in asthma patients.

METHODS

Cross-sectional data collected on PA (ActiGraph GT3X-BT), asthma control (the Asthma Control Questionnaire; ACQ), and BMI were examined in 206 adults (mean[sd] age 47.2[13.8] years; 49.5% had an obese BMI) with clinically diagnosed asthma. Relationships between PA and continuous BMI and asthma control were assessed using linear regression. Differences in PA across obesity (non-obese: <30 Kg/m2/obese: ≥30 Kg/m2) and asthma control categories (controlled: ≤0.75/uncontrolled: >0.75 ACQ score) were also examined.

RESULTS

Median (p25, p75) steps counts and peak cadence were 6035 (4248, 8461) steps/day and 123 (115, 133) steps in a minute, respectively. There were nearly 2000 fewer steps/day among those with uncontrolled asthma versus controlled and among those with obese BMI versus nonobese, respectively (both p < 0.05). In regression models adjusted for relevant covariates each 1-unit increase in ACQ score was associated with -686 [95%CI -997, -13] (p ≤ 0.05) average steps/day. The statistical significance of these findings was attenuated (p ≥ 0.05) when BMI was added to the model. However, the point estimate was not reduced (-766 [95%CI -1060, 34].

CONCLUSIONS

Overall step counts were low in this population despite peak cadence values suggesting that most participants could perform moderate intensity activity. Increasing step counts should be considered an important lifestyle intervention goal in obese and non-obese asthma patients with low PA levels.

Genomics of Treatable Traits in Asthma

The astounding number of genetic variants revealed in the 15 years of genome-wide association studies of asthma has not kept pace with the goals of translational genomics. Moving asthma diagnosis from a nonspecific umbrella term to specific phenotypes/endotypes and related traits may provide insights into features that may be prevented or alleviated by therapeutical intervention. This review provides an overview of the different asthma endotypes and phenotypes and the genomic findings from asthma studies using patient stratification strategies and asthma-related traits. Asthma genomic research for treatable traits has uncovered novel and previously reported asthma loci, primarily through studies in Europeans. Novel genomic findings for asthma phenotypes and related traits may arise from multi-trait and specific phenotyping strategies in diverse populations.

Effect of obesity, lipids and adipokines on allergic rhinitis risk: a Mendelian randomization study

OBJECTIVES

Observational studies suggested that obesity may promote the development of allergic rhinitis. The aim of this study was to explore the association of obesity, lipids and adipokines with this allergic disease at the genetic level using Mendelian randomization strategies.

METHODS

Summary data for three obesity indicators (such as body mass index), eight lipid indicators (such as triglycerides) and six adipokines (such as interleukin-6 and adipocyte fatty acid-binding protein) were collected, and suitable instrumental variables were extracted from these summary data according to the three main assumptions of Mendelian randomization. Three Mendelian randomization methods (such as inverse variance weighted) were used to detect the casual effect of the above indicators on allergic rhinitis risk. Sensitivity analyses were performed to assess heterogeneity and horizontal pleiotropy.

RESULTS

After Bonferroni correction, the inverse variance weighted reported that elevated levels of interleukin-6 and adipocyte fatty acid-binding protein were nominally associated with the decreased risk of allergic rhinitis (OR = 0.870, 95% CI 0.765-0.990, p = 0.035; OR = 0.732, 95% CI 0.551-0.973, p = 0.032). The other Mendelian randomization methods supported these results. Obesity, lipids and other adipokines were not related to this allergic disease. Sensitivity analyses found no heterogeneity and horizontal pleiotropy in the study.

CONCLUSION

The study provided some interesting, but not sufficient, evidence to suggest that interleukin-6 and adipocyte fatty acid-binding protein might play a protective role in the development of allergic rhinitis at the genetic level. These findings should be validated by more research.

LEVEL OF EVIDENCE

This was a Mendelian randomized study with a level of evidence second only to clinical randomized trials, and higher than cohort and case-control studies.

The association of asthma duration with body mass index and Weight-Adjusted-Waist index in a nationwide study of the U.S. adults

BACKGROUNDS

The association between obesity and asthma has been of interest, but whether the duration of asthma has an effect on obesity is still limitedly studied.

AIM

The purpose of this study was to investigate the association between asthma duration and obesity-related indexes, where obesity-related indexes include Body mass index (BMI) and Weight-adjusted-waist index (WWI).

METHODS

Data from National Health and Nutrition Examination Survey (NHANES) 2009-2018 were obtained to conduct this cross-sectional study. Duration of asthma was used as the independent variable and obesity-related indexes as the response variables. Multiple linear regression was used to assess the association between the independent variable and the response variables, and subsequently smoothed curve fitting and threshold effect analysis were performed to clarify whether there was a nonlinear correlation between the independent variable and the response variables. Finally, subgroup analysis was conducted to find sensitive populations.

RESULTS

A total of 9170 participants were included in the analysis. Asthma duration was statistically different between the two groups when all participants were grouped by median WWI (Q1 < 11.65, Q2 ≥ 11.65) (P < 0.001), but not by median BMI (Q1 < 31.8, Q2 ≥ 31.8) (P = 0.130). There was a positive association between asthma duration and WWI [β = 0.016, 95% CI (0.016, 0.017)], but a negative one with BMI [β = - 0.098, 95% CI (- 0.112, - 0.085)], and the correlations between the independent and response variables became more pronounced with increasing asthma duration (P for trend < 0.01). In addition, there were nonlinear relationships between asthma duration with BMI and WWI (log likelihood ratio < 0.001), with the best valid inflection points for asthma duration being 2 years (with WWI as the response variable) and 3 years (with BMI as the response variable), respectively. In the subgroup analysis, the positive association between asthma duration and WWI was more pronounced in the participants who were male, aged less than 40 years, and had asthma onset before 12 years of age. In contrast, when BMI was used as the response variable, the negative association between it and asthma duration was more pronounced among participants of female, aged 60 years or older, and with asthma onset less than 12 years of age.

CONCLUSIONS

In US adults, asthma duration might cause changes in obesity-related indexes. Longer asthma duration might cause weight loss, but might increase the risk of abdominal obesity.

Epidemiology of Asthma: Prevalence and Burden of Disease

Asthma, a common airway disease, results in a significant burden to both patients and society worldwide. Yet, despite global political commitment backed by the United Nations, progress to reduce the burden of asthma remains inadequate. This is particularly true in low-income countries. To date, progress has been delayed by the lack of uniform data collection, imperfect surveillance methods, inadequate resources, poor access to effective therapies, substandard asthma education, ineffective governmental policies, rapid urbanization, progressive increase in asthma prevalence, increased life expectancy and obesity rates worldwide, asthma heterogeneity and disease complexity, smoking, and environmental exposures to allergens and pollution. A thorough understanding of the challenges facing the international community is essential to define future strategies to improve the burden of asthma.

Human matters in asthma: Considering the microbiome in pulmonary health

Microbial communities form an important symbiotic ecosystem within humans and have direct effects on health and well-being. Numerous exogenous factors including airborne triggers, diet, and drugs impact these established, but fragile communities across the human lifespan. Crosstalk between the mucosal microbiota and the immune system as well as the gut-lung axis have direct correlations to immune bias that may promote chronic diseases like asthma. Asthma initiation and pathogenesis are multifaceted and complex with input from genetic, epigenetic, and environmental components. In this review, we summarize and discuss the role of the airway microbiome in asthma, and how the environment, diet and therapeutics impact this low biomass community of microorganisms. We also focus this review on the pediatric and Black populations as high-risk groups requiring special attention, emphasizing that the whole patient must be considered during treatment. Although new culture-independent techniques have been developed and are more accessible to researchers, the exact contribution the airway microbiome makes in asthma pathogenesis is not well understood. Understanding how the airway microbiome, as a living entity in the respiratory tract, participates in lung immunity during the development and progression of asthma may lead to critical new treatments for asthma, including population-targeted interventions, or even more effective administration of currently available therapeutics.

Overlaps between obstructive sleep apnoea and other respiratory diseases, including COPD, asthma and interstitial lung disease

In the past, there was limited research relating to the role of sleep in respiratory diseases. Physicians treating these patients tended to focus mainly on the daily disabling symptoms, overlooking the possible significant role of coexisting sleep disorders such as obstructive sleep apnoea (OSA). Nowadays, OSA has been recognised as an important, highly prevalent comorbidity for respiratory diseases such as COPD, asthma and interstitial lung diseases (ILDs). Overlap syndrome refers to the coexistence of chronic respiratory disease and OSA in the same patient. Although, in the past, overlap syndromes have been poorly studied, recent data underline that they result in increased morbidity and mortality compared with either underlying disorder alone. OSA and respiratory disease may be of different severity, and this, along with the existence of various clinical phenotypes, points to the necessity of an individualised therapeutic plan. Early recognition and OSA management could offer key benefits, such as improved sleep, quality of life and disease outcomes.

Educational aims

Describe pathophysiological aspects of OSA in chronic respiratory diseases such as COPD, asthma and ILDs.Understand the bidirectional clinical importance when OSA coexists in chronic respiratory diseases.Review current knowledge of treatment strategies towards an individualised therapeutic plan resulting in patient-centric outcomes.

All Types Obesity and Physical Inactivity Associated with the Risk of Activity of Daily Living Limitations Among People with Asthma

Purpose

To examine the association between all types of obesity, physical inactivity, and the risk of activity of daily living limitations in people with asthma.

Patients and Methods

In this cross-sectional study, data from 2555 people aged between 25 and 74 years were acquired from the National Survey of Midlife Development in the United States Refresher conducted between 2011 and 2014. Self-reported questions were used to specify the presence or absence of asthma and physical inactivity. All participants were categorized as having no asthma or asthma. Obesity was defined based on three distinctive indicators: body mass index, waist circumference, and waist-to-hip ratio.

Results

Logistic regression analysis showed that people with asthma who had all types of obesity alone or both all types of obesity and physical inactivity were significantly (P <0.0001) almost more than three times more likely to have limitations in the activity of daily living than those without this condition, even after adjusting for all covariates. Moreover, the odds of activity of daily living limitations were 1.69 times increased in asthma patients with physical inactivity alone, but this increase in risk was not significant (P =0.465). In addition, the odds of activity of daily living limitations were significantly (P <0.0001) more than twice independently in people with asthma aged between 60 and 74 years, female, undergraduate level of education, smoking, and having joint/bone underlying diseases.

Conclusion

The results demonstrated that the presence of all types of obesity is related to a higher risk of activity of daily living limitations in people with asthma than in those without asthma. Having both all types of obesity and physical inactivity are also linked to a greater risk of activity of daily living limitations in these patients.

Anxiety and Comorbidities Differences in Adults with Chronic Pulmonary Diseases: Serbian Single Center Experience

Background and objectives: The purpose of this study is to investigate the differences in the degree of the anxiety and comorbidity levels in patients with different chronic pulmonary diseases such as chronic obstructive bronchitis (COPD) without emphysema phenotype, pulmonary emphysema, bronchial asthma and lung cancer. Materials and Methods: The prospective clinical study included 272 patients that were diagnosed and treated of pulmonary pathology. COPD (without emphysema phenotype) (Group-1), pulmonary emphysema (Group-2), bronchial asthma (Group-3) and lung cancer (Group-4) were assessed. For the evaluation of the anxiety degree, we used Hamilton Anxiety Rating Scale (HAM-A). Results: The degree of cardiovascular symptoms was significantly higher in Group-1 versus Group-2 (p < 0.001), Group-3 (p = 0.001) and Group-4 (p = 0.013), and significantly higher in Group-4 versus Group-2 (p = 0.046). The degree of respiratory symptoms was significantly higher in Group-1 versus Group-2 (p < 0.001), Group-3 (p < 0.001) and Group-4 (p = 0.002), and significantly higher in Group-4 versus Group-2 (p = 0.013) and versus Group-3 (p = 0.023). For gastrointestinal symptoms, the degree of one was significantly higher in Group-1 versus Group-2 (p < 0.001), Group-3 (p < 0.001) and Group-4 (p = 0.017). Somatic subscale values were significantly higher in Group-1 versus Group-2 (p < 0.001), Group-3 (p < 0.001) and Group-4 (p = 0.015), and significantly higher in Group-4 versus Group-2 (p = 0.024). Total HAM-A score was significantly higher in Group-1 versus Group-2 (p = 0.002) and Group-3 (p = 0.007). Conclusions: Patients with COPD (without emphysema phenotype) followed by the lung cancer are at elevated risk of being more mentally challenged in terms of increased anxiety. Furthermore, patients with exacerbation of evaluated pulmonary pathologies have various levels of comorbidities degrees.