Treatment with a synbiotic concept reduces asthma-like symptoms and induces regulatory responses in a murine model of chronic allergic asthma

Introduction: Asthma is a chronic inflammatory disease affecting over 300 million people worldwide. Despite the effectiveness of the current treatments, over 50% of asthmatics are poorly controlled. Recently, a growing interest has emerged regarding the use of interventions that target the intestinal microbiota in allergic diseases and related conditions. This study explores the therapeutic effects of long-term treatment with a specific synbiotic combination on asthmalike symptoms in an allergic asthma model. Methods: Mice were sensitised twice (day 1 and 12) with ovalbumin (OVA)-imject alum intraperitoneally and challenged from day 17 to 23 daily with OVA aerosols. From day 24 to day 56, the animals were challenged with OVA three times a week. From day 22, the animals were treated with control solution or a synbiotic concept (Bifidobacterium breve M-16V, short- and long-chain oligosaccharides) by oral gavage three times a week. Pulmonary airway inflammation, Thspecific cytokines and transcription factors in lung tissue, mast cell degranulation, airway remodeling and other parameters were examined in BALB/c mice. Results: The synbiotic concept suppressed pulmonary airway inflammation, reduced mucosal mast cell protease, modulated cytokine expression and T cell transcription factors, and reduced airway remodeling features. The concept induced regulatory T cell responses as shown by increased Il10 and Foxp3 transcription in lung tissue and a higher ratio of Foxp3 to Gata3 and Rorct expression. In addition, the concept increased the Foxp3 mean fluorescence intensity in blood CD4+ T cells. Conclusion: This specific synbiotic combination, administered in a therapeutic way, has strong antiinflammatory properties and induces regulatory responses in a chronic allergic asthma model. Interestingly, oral gavage with the concept leads to modulation of immune responses in the lungs, showing immunomodulatory effects that are not limited to the gastro-intestinal tract. This concept may be beneficial in the treatment of chronic asthma and/or allergic conditions.