Probiotics: Potent Immunomodulatory Tool Against Allergy

Dose-Response Effect of Saccharomyces cerevisiae UFMG A-905 on the Prevention of Asthma in an Animal Model

Probiotics should be administered in adequate amounts to confer health benefits. Probiotic dose-response studies are still missing. Saccharomyces cerevisiae UFMG A-905 prevented asthma development; however, the ideal dose has not been investigated. We evaluated the optimal dose and administration regimen of S. cerevisiae UFMG A-905 in the prevention of asthma. Male Balb/c mice were sensitized intraperitoneally with ovalbumin (OVA) and challenged with OVA intranasally. Mice received, via gavage, daily or alternate-day S. cerevisiae UFMG A-905. In daily regimen, different concentrations (107, 108, or 109 CFU/mL) were given 10 days before OVA sensitization and during challenges. In alternate-day regimen, a concentration of 109 CFU/mL was administered three times per week for 5 weeks, starting 2 weeks prior to the first sensitization. After the last challenge, in vivo bronchial hyperresponsiveness and airway and lung inflammation were assessed. OVA-challenged mice, when compared to saline-challenged mice, presented a significant increase in bronchial hyperresponsiveness and airway and lung inflammation. Daily and alternate-day administration of 109 CFU/mL of S. cerevisiae UFMG A-905 significantly reduced bronchial hyperresponsiveness; lower concentrations of S. cerevisiae UFMG A-905 did not significantly reduce bronchial hyperresponsiveness. Daily regimen with the highest concentration significantly reduced total cell number, eosinophil count in the BAL, and the levels of IL-4, IL-5, and IL-13. Daily administration of S. cerevisiae UFMG A-905 at 107 and 108 CFU/mL and alternate-day regimen did not significantly decrease airway and lung inflammation. S. cerevisiae UFMG A-905 led to a significant attenuation of bronchial hyperresponsiveness and lung inflammation in a dose-dependent manner.

The Upper Airway Microbiota, Environmental Exposures, Inflammation, and Disease

Along with playing vital roles in pathogen exclusion and immune system priming, the upper airways (UAs) and their microbiota are essential for myriad physiological functions such as conditioning and transferring inhaled air. Dysbiosis, a microbial imbalance, is linked with various diseases and significantly impedes the quality of one’s life. Daily inhaled exposures and/or underlying conditions contribute to adverse changes to the UA microbiota. Such variations in the microbial community exacerbate UA and pulmonary disorders via modulating inflammatory and immune pathways. Hence, exploring the UA microbiota’s role in maintaining homeostasis is imperative. The microbial composition and subsequent relationship with airborne exposures, inflammation, and disease are crucial for strategizing innovating UA diagnostics and therapeutics. The development of a healthy UA microbiota early in life contributes to normal respiratory development and function in the succeeding years. Although different UA cavities present a unique microbial profile, geriatrics have similar microbes across their UAs. This lost community segregation may contribute to inflammation and disease, as it stimulates disadvantageous microbial–microbial and microbial–host interactions. Varying inflammatory profiles are associated with specific microbial compositions, while the same is true for many disease conditions and environmental exposures. A shift in the microbial composition is also detected upon the administration of numerous therapeutics, highlighting other beneficial and adverse side effects. This review examines the role of the UA microbiota in achieving homeostasis, and the impact on the UAs of environmental airborne pollutants, inflammation, and disease.

The microbiome of the upper respiratory tract in health and disease

The human upper respiratory tract (URT) offers a variety of niches for microbial colonization. Local microbial communities are shaped by the different characteristics of the specific location within the URT, but also by the interaction with both external and intrinsic factors, such as ageing, diseases, immune responses, olfactory function, and lifestyle habits such as smoking. We summarize here the current knowledge about the URT microbiome in health and disease, discuss methodological issues, and consider the potential of the nasal microbiome to be used for medical diagnostics and as a target for therapy.

Probiotics for the airways: Potential to improve epithelial and immune homeostasis

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefit on the host. The therapeutic effects of probiotics have been mostly studied in the gastrointestinal tract, but recent evidence points toward the potential of these bacteria to prevent and/or treat chronic airway diseases. In this review, possible mechanisms of action of probiotics in the airways are described, with a particular focus on their capacity to modulate the epithelial barrier function and their mode of interaction with the immune system. Indeed, probiotic bacteria, mostly lactobacilli, can promote the expression and regulation of tight junctions and adherence junctions, resulting in the restoration of a defective epithelial barrier. These bacteria interact with the epithelial barrier and immune cells through pattern recognition receptors, such as Toll-like receptors, which upon activation can stimulate or suppress various immune responses. Finally, the clinical potential of probiotics to treat inflammatory diseases of the upper and lower respiratory tract, and the difference between their mode of application (eg, oral or nasal) are discussed here.

Specific immunotherapy plus Clostridium butyricum alleviates ulcerative colitis in patients with food allergy

The aberrant T cell activation plays an important role in the pathogenesis of intestinal inflammation, such as ulcerative colitis (UC). C. butyricum (Cb) is a probiotic and has been employed in the treatment of immune diseases. This study tests a hypothesis that specific immunotherapy (SIT) plus oral Cb (an over-the-counter probiotic) alleviates the UC symptoms. In this study, we conducted a randomized, double-blind, clinical study at our hospital. A total of 80 patients with relapsing-remitting ulcerative colitis and high levels of specific IgE antibody was randomly divided into 4 groups, and were treated with SIT or/and Cb, or placebo, respectively for 1 year. The results showed that a food antigen-specific Th2 polarization immune response was observed in UC patients with food allergy (FA). The frequency of regulatory B cells was significantly less in UC patients with FA as compared with healthy subjects. The UC patients with FA were treated with SIT and Cb showed significant amelioration of UC clinical symptoms, reduction of using UC-control medicines, and suppression of the skewed Th2 polarization, which did not occur in those treated with either SIT alone, or Cb alone, or placebo. In conclusion, combination of SIT and Cb efficiently alleviates a fraction of UC patients.