Association of antieosinophil therapy with decreased body mass index in patients with severe asthma: A preliminary retrospective analysis

Body Weight and Allergic Asthma: A Narrative Review

Obesity is a known risk factor for asthma development, progression, and exacerbation. Nevertheless, the underlying pathophysiological mechanisms explaining how obesity contributes to the development and progression of asthma have yet to be established. Here, we review human studies examining the associations between asthma and obesity, focusing on the literature from the past 10 years. Overall, current evidence suggests that while both asthma and obesity are complex diseases with significant heterogeneity, they both share various features of chronic inflammation. Furthermore, the interactions between asthma and obesity likely involve allergen-specific T helper type 2 (type 2) immune responses, as well as diverse non-type 2 inflammatory pathways. However, despite considerable progress, studies to date have not definitively elucidated the mechanisms that account for the observed association. A large-scale population-based study combined with translational immunological research, including targeted asthma therapies and pharmacological weight loss therapies, may be required to properly dissect the details of obesity-related asthma pathophysiology.

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.

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.

Origins and functions of eosinophils in two non-mucosal tissues

Eosinophils are a type of granulocyte named after the presence of their eosin-stained granules. Traditionally, eosinophils have been best known to play prominent roles in anti-parasitic responses and mediating allergic reactions. Knowledge of their behaviour has expanded with time, and they are now recognized to play integral parts in the homeostasis of gastrointestinal, respiratory, skeletal muscle, adipose, and connective tissue systems. As such, they are implicated in a myriad of pathologies, and have been the target of several medical therapies. This review focuses on the lifespan of eosinophils, from their origins in the bone marrow, to their tissue-resident role. In particular, we wish to highlight the functions of eosinophils in non-mucosal tissues with skeletal muscle and the adipose tissues as examples, and to discuss the current understanding of their participation in diseased states in these tissues.

Effects of biological therapies on patients with Type-2 high asthma and comorbid obesity

Over 20 million adults and 6 million children in the United States (US) have asthma, a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, and mucus hypersecretion. Obesity, another highly prevalent disease in the US, is a major risk factor for asthma and a significant cause of diminished asthma control, increased submucosal eosinophilia, and reduced quality of life. A large subgroup of these patients experiences severe symptoms and recurrent exacerbations despite maximal dosage of standard asthma therapies. In the past two decades, the development of biological therapies has revolutionized the field and advanced our understanding of type 2 inflammatory biomarkers. However, patients with obesity and comorbid asthma are not principally considered in clinical trials of biologics. Large landmark cluster analyses of patients with asthma have consistently identified specific asthma phenotypes that associate with obesity but may be differentiated by age of asthma onset and inflammatory cell profiles in sputum. These patterns suggest that biologic processes driving asthma pathology are heterogenous among patients with obesity. The biological mechanisms driving pathology in patients with asthma and comorbid obesity are not well understood and likely multifactorial. Future research needs to be done to elicit the cellular and metabolic functions in the relationship of obesity and asthma to yield the best treatment options for this multiplex condition. In this review, we explore the key features of type 2 inflammation in asthma and discuss the effectiveness, safety profile, and research gaps regarding the currently approved biological therapies in asthma patients with obesity.

Eosinophils in obesity and obesity-associated disorders

Despite the rising prevalence and costs for the society, obesity etiology, and its precise cellular and molecular mechanisms are still insufficiently understood. The excessive accumulation of fat by adipocytes plays a key role in obesity progression and has many repercussions on total body physiology. In recent years the immune system as a gatekeeper of adipose tissue homeostasis has been evidenced and has become a focal point of research. Herein we focus on eosinophils, an important component of type 2 immunity, assuming fundamental, yet ill-defined, roles in the genesis, and progression of obesity and related metabolic disorders. We summarize eosinophilopoiesis and eosinophils recruitment into adipose tissue and discuss how the adipose tissue environments shape their function and vice versa. Finally, we also detail how obesity transforms the local eosinophil niche. Understanding eosinophil crosstalk with the diverse cell types within the adipose tissue environment will allow us to framework the therapeutic potential of eosinophils in obesity.

Long-Term Weight Changes After Starting Anti-IL-5/5Ra Biologics in Severe Asthma: The Role of Oral Corticosteroids

BACKGROUND

Many patients with severe asthma are overweight or obese, often attributed to unintentional weight gain as a side effect of oral corticosteroids (OCSs). Anti-IL-5/5Ra biologics significantly reduce OCS use, but their long-term effects on weight are unknown.

OBJECTIVES

To examine (1) weight change up to 2 years after anti-IL-5/5Ra initiation in subgroups on the basis of maintenance OCS use at start of treatment and (2) whether cumulative OCS exposure before or changes in OCS exposure during treatment are related to weight change.

METHODS

Real-world data on weight and cumulative OCS dose from adults included in the Dutch Registry of Adult Patients with Severe asthma for Optimal DIsease management before and at least 2 years after starting anti-IL-5/5Ra were analyzed using linear mixed models and linear regression analyses.

RESULTS

For the included 389 patients (55% female; mean body mass index, 28 ± 5 kg/m2; 58% maintenance OCS), mean weight decreased -0.27 kg/y (95% CI, -0.51 to -0.03; P = .03), with more weight loss in patients with maintenance OCS use than in those without maintenance OCS use (-0.87 kg/y [95% CI, -1.21 to -0.52; P < .001] vs +0.54 kg/y [0.26 to 0.82; P < .001]). Greater weight loss at 2 years was associated with higher cumulative OCS dose in the 2 years before anti-IL-5/5Ra initiation (β = -0.24 kg/g; 95% CI, -0.38 to -0.10; P < .001) and, independently, greater reduction in cumulative OCS dose during follow-up (β = 0.27 kg/g; 95% CI, 0.11 to 0.43; P < .001).

CONCLUSIONS

Anti-IL-5/5Ra therapy is associated with long-term weight reduction, especially in patients with higher OCS exposure before treatment and those able to reduce OCS use during treatment. However, the effect is small and does not apply to all patients, and so additional interventions seem necessary if weight change is desired.

Obesity-associated asthma in childhood

Obesity and bronchial asthma are very common diseases in children and adolescents, associated with a considerable burden of disease, reduced quality of life and comorbidities. Obesity is a significant risk factor for bronchial asthma. On the one hand, obesity leads to changes in the mechanics and function of the lungs and chest. On the other hand, obesity-associated inflammatory processes with increased production of leptin and cytokines may trigger bronchial inflammation with the appearance of asthmatic symptoms. The diseases are also linked by genetic factors. Physical activity and weight reduction have a significant benefit. Pharmacotherapy must be based on the pattern of inflammation. This article summarizes the current state of the literature on the association of asthma and obesity and presents current and possible future treatment options.

Unraveling the connection between eosinophils and obesity

Obesity affects more than 650 million adults worldwide and is a major risk factor for a variety of serious comorbidities. The prevalence of obesity has tripled in the past forty years and continues to rise. Eosinophils have recently been implicated in providing a protective role against obesity. Decreasing eosinophils exacerbates weight gain and contributes to glucose intolerance in high fat diet-induced obese animals, while increasing eosinophils prevents high-fat diet-induced adipose tissue and body weight gain. Human studies, however, do not support a protective role for eosinophils in obesity. More recent animal studies have also reported conflicting results. Considering these contradictory findings, the relationship between eosinophils and obesity may not be unidirectional. In this mini-review, we summarize a recent debate regarding the role of adipose tissue eosinophils in metabolic disorders, and discuss local and systemic effects of eosinophils in obesity. Given that adipose eosinophils play a role in tissue homeostasis, more research is needed to understand the primary function of adipose tissue eosinophils in their microenvironment. Therapeutic interventions that target eosinophils in adipose tissue may have the potential to reduce inflammation and body fat, while improving metabolic dysfunction in obese patients.