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BackgroundAsthma is estimated to affect as many as 300 million people worldwide and its incidence and prevalence are rapidly increasing throughout the world, especially in children and within developing countries. Recently, there has been a growing interest in the use of potentially beneficial bacteria for allergic diseases. This study is aimed at exploring the therapeutic effects of long-term treatment with two different beneficial bacterial strains (Bifidobacterium breve M-16 V and Lactobacillus rhamnosus NutRes1) and a glucocorticoid (budesonide), as a reference treatment, on inflammatory response in a murine model for chronic allergic asthma.MethodsTo mimic the chronic disease in asthmatic patients, we used the murine ovalbumin-induced asthma model combined with prolonged allergen exposure. Airway function; pulmonary airway inflammation; airway remodelling, mRNA expression of pattern recognition receptors, Th-specific cytokines and transcription factors in lung tissue; mast cell degranulation; in vitro T cell activation; and expression of Foxp3 in blood Th cells were examined.ResultsLactobacillus rhamnosus reduced lung resistance to a similar extent as budesonide treatment in chronically asthmatic mice. Pulmonary airway inflammation, mast cell degranulation, T cell activation and airway remodelling were suppressed by all treatments. Beneficial bacteria and budesonide differentially modulated the expression of toll-like receptors (TLRs), nod-like receptors (NLRs), cytokines and T cell transcription factors. Bifidobacterium breve induced regulatory T cell responses in the airways by increasing Il10 and Foxp3 transcription in lung tissue as well as systemic by augmenting the mean fluorescence intensity of Foxp3 in blood CD4+ T cells.ConclusionThese findings show that Bifidobacterium breve M-16 V and Lactobacillus rhamnosus NutRes1 have strong anti-inflammatory properties that are comparable to budesonide and therefore may be beneficial in the treatment of chronic asthma.

Over the last decade, there has been a growing interest in the use of interventions that target the intestinal microbiota as a treatment approach for asthma. This study is aimed at exploring the therapeutic effects of long-term treatment with a combination of Bifidobacterium breve with non-digestible oligosaccharides on airway inflammation and remodeling. A murine ovalbumin-induced chronic asthma model was used. Pulmonary airway inflammation; mRNA expression of pattern recognition receptors, Th-specific cytokines and transcription factors in lung tissue; expression of Foxp3 in blood Th cells; in vitro T cell activation; mast cell degranulation; and airway remodeling were examined. The combination of B. breve with non-digestible oligosaccharides suppressed pulmonary airway inflammation; reduced T cell activation and mast cell degranulation; modulated expression of pattern recognition receptors, cytokines and transcription factors; and reduced airway remodeling. The treatment induced regulatory T cell responses, as shown by increased Il10 and Foxp3 transcription in lung tissue, and augmented Foxp3 protein expression in blood CD4+CD25+Foxp3+ T cells. This specific combination of beneficial bacteria with non-digestible oligosaccharides has strong anti-inflammatory properties, possibly via the induction of a regulatory T cell response, resulting in reduced airway remodeling and, therefore, may be beneficial in the treatment of chronic inflammation in allergic asthma.