Obesity affects type 2 biomarker levels in asthma

Obesity-related asthma: new insights leading to a different approach

PURPOSE OF REVIEW

Obesity is a growing global health threat that significantly contributes to the burden of asthma by increasing the risk of developing asthma and exerting a distinct effect on lung function and inflammation. The treatment of obesity-related asthma is hindered by a poor response to standard asthma treatments, leading to worse asthma control. Weight loss strategies have a significant effect on asthma symptoms but are not feasible for a large proportion of patients, underscoring the need for a better understanding of the pathophysiology and the development of additional treatment options.

RECENT FINDINGS

Recent literature focusing on pathophysiology particularly delved into nontype 2 inflammatory mechanisms, associations with the metabolic syndrome and small airway impairment. Additionally, several new treatment options are currently investigated, including biologics, weight reduction interventions, and novel antiobesity drugs.

SUMMARY

Obesity-related asthma is a highly prevalent asthma phenotype for which weight loss strategies currently stand as the most specific treatment. Furthermore, novel pharmacological interventions aiming at metabolic processes are on the way.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Impact of obesity in asthma: Possible future therapies

Obesity is one of the factors associated with the severity of asthma. Obesity is associated with aggravation of the pathophysiology of asthma, including exacerbations, airway inflammation, decreased pulmonary function, and airway hyperresponsiveness. The present review addresses the characteristics of asthma with obesity, focusing especially on the heterogeneity caused by the degree of type 2 inflammation, sex differences, the onset of asthma, and race differences. To understand the severity mechanisms in asthma and obesity, such as corticosteroid resistance, fatty acids, gut microbiome, and cytokines, several basic research studies are evaluated. Finally, possible future therapies, including weight reduction, microbiome-targeted therapies, and other molecular targeted therapies are addressed. We believe that the present review will contribute to better understanding of the severity mechanisms and the establishment of novel treatments for severe asthma patients with obesity.

[Unmet Needs in Severe Allergic Asthma]

Severe asthma affects 3%-10% of the world's population, according to estimates by the Global Initiative for ASTHMA (GINA). Allergic asthma is one of the most common phenotypes of severe asthma and it is characterized by allergen-induced type 2 inflammation in which immunoglobulin E (IgE) is a key mediator, making it an important therapeutic target. The introduction of targeted biological therapies or treatments has entered the management for severe asthma in the era of precision medicine, and the goal of treatment is clinical remission of the disease. There is a significant percentage of patients with severe allergic asthma who do not respond to treatments and whose symptoms are not controlled. In this paper, a group of experts in the management of severe allergic asthma reviewed and evaluated the most relevant evidence regarding the pathophysiology and phenotypes of severe allergic asthma, the role of IgE in allergic inflammation, allergen identification, techniques, biomarkers and diagnostic challenges, available treatments and strategies for disease management, with a special focus on biological treatments. From this review, recommendations were developed and validated through a Delphi consensus process with the aim of offering improvements in the management of severe allergic asthma to the professionals involved and identifying the unmet needs in the management of this pathology.

Biomarkers: Promising and valuable tools towards diagnosis, prognosis and treatment of Covid-19 and other diseases

The use of biomarkers as early warning systems in the evaluation of disease risk has increased markedly in the last decade. Biomarkers are indicators of typical biological processes, pathogenic processes, or pharmacological reactions to therapy. The application and identification of biomarkers in the medical and clinical fields have an enormous impact on society. In this review, we discuss the history, various definitions, classifications, characteristics, and discovery of biomarkers. Furthermore, the potential application of biomarkers in the diagnosis, prognosis, and treatment of various diseases over the last decade are reviewed. The present review aims to inspire readers to explore new avenues in biomarker research and development.

A new approach for the detection of obesity-related airway obstruction in lung-healthy individuals

BACKGROUND

Subjects with obesity show an increased prevalence of airway obstruction but it is not clear in each case whether this reflects genuine lung disease. Via intentional increase in end-expiratory lung volume we studied the detection of obesity-induced airway obstruction in lung-healthy obese subjects.

METHODS

The primary study population comprised 66 lung-healthy obese subjects and 23 normal weight subjects. Measurements were performed in a body plethysmograph allowing for recording and quantification of breathing loops in terms of specific airway resistance at both normal and intentionally elevated end-expiratory lung volume. The change in volume was documented by a shutter maneuver.

RESULTS

The voluntary increase of lung volume led to a significant reduction of expiratory airway resistance in 11 of the 66 obese subjects. This reduction could be quantified by a change of total expiratory resistance (sRtEX) of >1 kPa*s but was also clearly visible in the breathing loops. sRtEX showed the largest change among all resistance parameters. The loops of normal weight subjects remained virtually unaffected by the change in lung volume. Moreover, those of 5 obese patients with COPD who were measured for comparison partially showed a reduction of resistance but airway obstruction remained.

CONCLUSION

The proposed breathing maneuver was simple to perform and allowed for a quantitative and qualitative detection of obesity-induced airway obstruction. This might help in reducing the likelihood of misdiagnosis and overtreatment of obese patients.