Beneficial bacteria and non-digestible oligosaccharides for the treatment of chronic allergic asthma: modulation of immune responses. Studies in murine models

The worldwide prevalence of allergic diseases, such as asthma, is rising dramatically. Despite the effectiveness of the current therapies for asthma, a high percentage of asthmatics are poorly controlled. Novel therapeutic strategies for asthma management are strongly needed. Understanding the immune responses and the different inflammatory markers involved in asthma is crucial for the development of effective, safe and potential therapeutic treatment approaches. This thesis aims at understanding the immune responses underlying allergic asthma and the modulation of these responses and asthma symptoms by using beneficial bacterial strains, Bifidobacterium breve M-16V and Lactobacillus rhamnosus NutRes1, with or without specific non-digestible oligosaccharides. The findings described in this thesis demonstrate that immune and inflammatory responses are differentially regulated in mild and severe allergic asthma, as represented by the different mRNA expression profiles of TLRs, NLRs and T helper-specific cytokines and transcription factors. Additionally, various anti-inflammatory and anti-allergic properties of Bifidobacterium breve M-16V alone or in combination with a specific mixture of non-digestible oligosaccharides, and Lactobacillus rhamnosus NutRes1 are found. An interesting finding was that orally-administered beneficial bacteria modulated the immune responses at site of inflammation, in the lungs, as well as systemic. These results highlight the therapeutic potential of these beneficial bacterial strains for chronic allergic asthma management. Further investigation is needed to understand the mechanism underlying the immunomodulatory effects of these bacterial strains.