Oral Probiotic Administration to Modulate the Airway Microbiome in Obese Asthmatic Subjects

Overview

Obesity is a major health concern in the Deep South resulting in a growing number of metabolic disorders that strain the resources of our healthcare system. Obesity is recognized as a major risk factor for asthma. The Centers for Disease Control and Prevention (CDC) has stated "obesity is associated significantly with the development of asthma, worsening asthma symptoms, and poor asthma control. This leads to increased medication use and hospitalizations." Variations in the airway microbiome are correlated with the risk for development of asthma, and populations of different bacteria vary by phenotype amongst severe asthmatics . Proteobacteria are found in greater proportion in asthmatic subjects relative to healthy controls (37% vs 15%) while non-asthmatic subjects have a relative abundance of Firmicutes (47% vs 63%) and Actinobacteria (10% vs 14%) compared to those with asthma . Amongst those with asthma, obese asthmatic subjects have a relative abundance of Bacteroides (54%) and Firmicutes (26%). Notably, both phyla are part of the gastrointestinal microbiome, suggesting inoculation through gastroesophageal reflux which may be more common in obese individuals. Asthmatics identified as having improvement in their asthma control following treatment with inhaled corticosteroids appear to have a greater relative abundance of Actinobacteria (79.8%) in their airways relative to other asthmatics. Actinobacteria have been associated with the production of anti-inflammatory proteins and are speculated to be involved in increasing steroid responsiveness. Other studies have demonstrated that oral administration of probiotics, including Bifidobacterium species within the phyla Actinobacteria, lead to reduced Th2 cytokine production and eosinophilic inflammation, along with promotion of Regulatory T-cell (Treg) populations within the airway. We hypothesize that administration of over the counter oral probiotics containing Actinobacteria (Bifidobacterium) to obese asthmatic subjects will result in decreased airway inflammation and better asthma control by immune modulation.