Oral application of lactic acid bacteria following treatment with antibiotics inhibits allergic airway inflammation

Protective effects of different Bacteroides vulgatus strains against lipopolysaccharide-induced acute intestinal injury, and their underlying functional genes

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Different Bacteroides vulgatus strains have varying effects on inflammatory diseases.

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B. vulgatus FTJS7K1 was screened due to its role in alleviating inflammation.

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B. vulgatus FTJS7K1 can modulate gut microbial community.

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B. vulgatus FTJS7K1 can regulate the levels of related cytokines.

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The genes about SCFAs secretion are responsible for the anti-inflammatory effect.

Introduction

The roles of Bacteroides species in alleviating inflammation and intestinal injury has been widely demonstrated, but few studies have focused on the roles of Bacteroides vulgatus.

Objectives

In this study, four B. vulgatus strains were selected, based on their genomic characteristics, to assess their ability to alleviate lipopolysaccharide (LPS)-induced acute intestinal injury in C57BL/6J mice.

Methods

Alterations in the intestinal microbiota, intestinal epithelial permeability, cytokine level, short-chain fatty acid (SCFA) concentration, and immune responses were investigated following LPS-induced acute intestinal injury in C57BL/6J mice.

Results

Severe histological damage and a significant change in cytokine expression was observed in the mouse colon tissues 24 h after LPS administration. Oral administration of different B. vulgatus strains showed different effects on the assessed parameters of the mice; particularly, only the administration of B. vulgatus FTJS7K1 was able to protect the architectural integrity of the intestinal epithelium. B. vulgatus FTJS7K1 also negated the LPS-induced changes in cytokine mRNA expression in the colon tissues, and in the proportion of regulatory T cells in the mesenteric lymph node. Compared with the LPS group, the B. vulgatus FTJS7K1 group showed significantly increased abundance of Lactobacillus, Akkermansia, and Bifidobacterium, and decreased abundance of Faecalibaculum. The B. vulgatus FTJS7K1 group also showed significantly increased concentration of SCFAs in fecal samples. The results of genomic analysis showed that these protective roles of B. vulgatus FTJS7K1 may be mediated through specific genes associated with defense mechanisms and metabolism (e.g., the secretion of SCFAs).

Conclusions

Our findings suggest that the protective role of B. vulgatus FTJS7K1 appear to be via modulation of cytokine production in the colon tissue and regulation of the structure of the gut microbiota. These results provide support for the screening of the Bacteroides genus for next-generation probiotics.

Association between probiotics and bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia is a chronic pulmonary disease with a high incidence in premature infants, and there is still no effective treatment. The purpose of our study was to analyze the association between the use of probiotics and BPD in premature infants. We retrospectively collected clinical data of infants with gestational age < 32 weeks admitted to the NICU of The First Hospital of Jilin University from January 1, 2019 to March 31, 2020. Demographic and clinicopathological data of the inclusion population were collected. The outcome was the incidence of BPD or death. The χ² tests was used to compare the categorical variables. The t test and non-parametric Wilcoxon rank-sum test were used to compare the continuous data. Univariate and multivariate logistic regression were used to analyze the association between probiotics and BPD. A total of 318 newborns met the inclusion criteria, of which 94 received probiotics and 224 received no probiotics. There were 16 deaths and 115 newborns with BPD in the included population. The results of univariate analysis showed differences in the maternal diabetes, the proportion of systemic antibiotics given to mother within 24 h before birth, the receiving rate of invasive mechanical ventilation, the prevalence of BPD/death, PDA, RDS and Ivh between newborns with and without probiotics (p < 0.05); The results of unadjusted univariate logistic regression model showed that probiotic (OR 0.034, 95% CI 0.012-0.096) was the factor affecting BPD in preterm infants (p < 0.05). Multivariate logistic regression result (OR 0.037, 95% CI 0.013-0.105) was consistent with univariate analysis (P < 0.001). Probiotics are associated with a reduced risk of BPD in preterm infants < 32 weeks of age. More prospective studies with large samples are still needed.

Physical properties of lactic acid bacteria influence the level of protection against influenza infection in mice

We evaluated whether the water dispersibility of lactic acid bacteria (Enterococcus faecalis KH2) affects their efficacy. When cultured lactic acid bacteria are washed, heat-killed, and powdered, adhesion occurs between results in aggregation (non-treated lactic acid bacteria, n-LAB). However, dispersed lactic acid bacteria (d-LAB) with a lower number of aggregates can be prepared by treating them with a high-pressure homogenizer and adding an excipient during powdering. Mice were administered n-LAB or d-LAB Peyer’s patches in the small intestine were observed. Following n-LAB administration, a high amount of aggregated bacteria drifting in the intestinal mucosa was observed; meanwhile, d-LAB reached the Peyer’s patches and was absorbed into them. Evaluation in a mouse influenza virus infection model showed that d-LAB was more effective than n-LAB in the influenza yield of bronchoalveolar lavage fluids on day 3 post-infection and neutralizing antibody titers of sera and influenza virus-specific immunoglobulin A in the feces on day 14 post-infection. Therefore, the physical properties of lactic acid bacteria affect their efficacy; controlling their water dispersibility can improve their effectiveness.

The specific use of alginate from Laminaria japonica by Bacteroides species determined its modulation of the Bacteroides community

Accumulating studies showed that the beneficial actions of polysaccharides were closely associated with an improvement of the gut microbiota, but mechanisms that link polysaccharides and gut microbiota alterations are ill defined. Alginate from Laminaria japonica (LJP-A) can avoid being digested by the upper digestive tract and reach the colon where it can improve the gut microbiota community. LJP-A increased the relative abundance of some Bacteroidaceae members, e.g. Bacteroides species. The distribution of Bacteroides species in the gut is specific to the individual, and the specific use of LJP-A by Bacteroides species can determine LJP-A-induced alterations of the intestinal Bacteroides community, in which carbon source-based syntrophic interactions occur in Bacteroides species of the human gut microbial ecosystem. Compared to other species, Bacteroides finegoldii responded more positively to LJP-A intervention, and its properties may have a close connection with the bioactivities of LJP-A. This study provides a rationale for personalized treatment with dietary polysaccharides that were optimally fermented within a particular individual.

Novel strains of Bacteroides fragilis and Bacteroides ovatus alleviate the LPS-induced inflammation in mice

Lipopolysaccharide (LPS) can promote the expression of pro-inflammatory cytokines, damage the tight junction of epithelial walls, and thereby lead to chronic low-grade intestinal inflammatory disorders. Evidences of many beneficial functions from Bacteroides strains suggest their intervention capabilities in LPS-induced inflammation. In the present study, both healthy and LPS-treated mice were consistently treated with Bacteroides strains for 5 days. The intestinal microbiota alteration, epithelial permeability, cytokine expression, and autoimmune and innate immune responses were analyzed. B. fragilis HCK-B3 and B. ovatus ELH-B2 from our laboratory collection were demonstrated to assist intestinal equilibrium by maintaining the diversity of gut microbiota and relieve LPS-induced inflammation by either modulating cytokine production or restoring the Treg/Th-17 balance. Our research indicated that the Bacteroides strains with capabilities of alleviating inflammation have the potential as therapeutics to prevent intestinal inflammatory disorders and provided scientific supports for discovering next-generation probiotics.

A Review on Gut Remediation of Selected Environmental Contaminants: Possible Roles of Probiotics and Gut Microbiota

Various environmental contaminants including heavy metals, pesticides and antibiotics can contaminate food and water, leading to adverse effects on human health, such as inflammation, oxidative stress and intestinal disorder. Therefore, remediation of the toxicity of foodborne contaminants in human has become a primary concern. Some probiotic bacteria, mainly Lactobacilli, have received a great attention due to their ability to reduce the toxicity of several contaminants. For instance, Lactobacilli can reduce the accumulation and toxicity of selective heavy metals and pesticides in animal tissues by inhibiting intestinal absorption of contaminants and enhancing intestinal barrier function. Probiotics have also shown to decrease the risk of antibiotic-associated diarrhea possibly via competing and producing antagonistic compounds against pathogenic bacteria. Furthermore, probiotics can improve immune function by enhancing the gut microbiota mediated anti-inflammation. Thus, these probiotic bacteria are promising candidates for protecting body against foodborne contaminants-induced toxicity. Study on the mechanism of these beneficial bacterial strains during remediation processes and particularly their interaction with host gut microbiota is an active field of research. This review summarizes the current understanding of the remediation mechanisms of some probiotics and the combined effects of probiotics and gut microbiota on remediation of foodborne contaminants in vivo.

Probiotic Supplementation in Preterm Infants Does Not Affect the Risk of Bronchopulmonary Dysplasia: A Meta-Analysis of Randomized Controlled Trials

Probiotic supplementation reduces the risk of necrotizing enterocolitis (NEC) and late-onset sepsis (LOS) in preterm infants, but it remains to be determined whether this reduction translates into a reduction of other complications. We conducted a systematic review and meta-analysis to evaluate the possible role of probiotics in altering the risk of bronchopulmonary dysplasia (BPD). Fifteen randomized controlled trials (4782 infants; probiotics: 2406) were included. None of the included studies assessed BPD as the primary outcome. Meta-analysis confirmed a significant reduction of NEC (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.33 to 0.81, p = 0.004; random effects model), and an almost significant reduction of LOS (RR 0.82, 95% CI 0.65 to 1.03, p = 0.084). In contrast, meta-analysis could not demonstrate a significant effect of probiotics on BPD, defined either as oxygen dependency at 28 days of life (RR 1.01, 95% CI 0.91 to 1.11, p = 0.900, 6 studies) or at 36 weeks of postmenstrual age (RR 1.07, 95% CI 0.96 to 1.20, p = 0.203, 12 studies). Meta-regression did not show any significant association between the RR for NEC or LOS and the RR for BPD. In conclusion, our results suggest that NEC and LOS prevention by probiotics does not affect the risk of developing BPD in preterm infants.

How do probiotics and prebiotics function at distant sites?

The realisation that microbes regarded as beneficial to the host can impart effects at sites distant from their habitat, has raised many possibilities for treatment of diseases. The objective of a workshop hosted in Turku, Finland, by the International Scientific Association for Probiotics and Prebiotics, was to assess the evidence for these effects and the extent to which early life microbiome programming influences how the gut microbiota communicates with distant sites. In addition, we examined how probiotics and prebiotics might affect the skin, airways, heart, brain and metabolism. The growing levels of scientific and clinical evidence showing how microbes influence the physiology of many body sites, leads us to call for more funding to advance a potentially exciting avenue for novel therapies for many chronic diseases.

Immunomodulatory Effects of Different Lactic Acid Bacteria on Allergic Response and Its Relationship with In Vitro Properties

Some studies reported that probiotic could relieve allergy-induced damage to the host, but how to get a useful probiotic is still a challenge. In this study, the protective effects of three lactic acid bacteria (La, Lp and Lc) were evaluated in a mouse model, and its relationship with the in vitro properties was analyzed. The in vitro results indicated that La with the capacity to inhibit IL-4 production could have a better anti-allergy effect in vivo than two others. However, the animal trials showed that all LAB strains could alleviate allergen-induced airway inflammation. Among them, LAB strain Lp had a better effect in inhibiting allergic response through a modulation of Th1/Th2 balance and an increase of regulatory T cells. This difference could be explained by that different LAB strains have a strain-specific effect on gut microbiota closely associated with host immune responses. Finally, this study did not only obtain an effective anti-allergy probiotic strain via animal study, but also indicate that probiotic-induced effect on intestinal microbiota should be considered as an important screening index, apart from its inherent characteristics.