Development of Gut Microbiota in a Mouse Model of Ovalbumin-induced Allergic Diarrhea under Sub-barrier System

Detection of the peripheral blood antigens and clinical value in recurrent aphthous ulcer: A cross-section study

Abstract Background/purpose

Recurrent aphthous ulcer (RAU) is one of the most common diseases of oral mucosa, which is generally believed to be related to immunity, though the etiology is still unclear. It is suspected that allergies are directly related to RAU. So we sought to explore the relationship between hypersensitivity and RAU.

Materials and methods

40 RAU patients who were in ulceration period and 40 people who were in good health were selected from Jan 2016 to Feb 2017, matched in age and sex. The peripheral blood antigens of 40 RAU patients and 40 healthy people was tested, and serum specific IgE (sIgE) with 6 groups of antigens and total IgE (tIgE) analysis was performed to identify IgE-mediated allergic reaction possibly affecting RAU. We then investigated the food intolerance and IgG levels to discover the correlation between non-IgE mediated allergic reaction and RAU.

Results

The positive cases and rate of sIgE in RAU group was higher than that of control, but the difference was not statistically significant (P＞0.05). Positive grade of animal fur scraps (EX1), house dust mixed (HX2) and the serum tIgE concentration of the RAU group were significantly higher than the control group (P＜0.05).The number of food intolerance in RAU group was significantly higher than that in control group (P＜0.05).

Conclusion

Our findings suggested certain correlation between RAU and anaphylaxis. Daily contact allergens and food intolerance may be one of the causes of RAU. Moreover, this provides reference value for clinical diagnosis and treatment.

Human Gut Microbiome Response Induced by Fermented Dairy Product Intake in Healthy Volunteers

Accumulated data suggests that the gut microbiome can rapidly respond to changes in diet. Consumption of fermented dairy products (FDP) fortified with probiotic microbes may be associated with positive impact on human health. However, the extent and details of the possible impact of FDP consumption on gut community structure tends to vary across individuals. We used microbiome analysis to characterize changes in gut microbiota composition after 30 days of oral intake of a yoghurt fortified with Bifidobacterium animalis subsp. lactis BB-12. 16S rRNA gene sequencing was used to assess the gut microbial composition before and after FDP consumption in healthy adults (n = 150). Paired comparison of gut microbial content demonstrated an increase in presence of potentially beneficial bacteria, particularly, Bifidobacterium genus, as well as Adlercreutzia equolifaciens and Slackia isoflavoniconvertens. At a functional level, an increased capacity to metabolize lactose and synthesize amino acids was observed accompanied by a lowered potential for synthesis of lipopolysaccharides. Cluster analysis revealed that study volunteers segregated into two groups with post-intervention microbiota response that was dependent on the baseline microbial community structure.

Allergen Immunization Induces Major Changes in Microbiota Composition and Short-Chain Fatty Acid Production in Different Gut Segments in a Mouse Model of Lupine Food Allergy

BACKGROUND

The incidence of food allergies in western countries has increased in recent decades.

OBJECTIVES

To study the association between gut bacterial microbiota composition, short-chain fatty acids (SCFAs) and food allergy in a mouse model.

METHODS

After oral immunizations with the human food allergen lupine with the adjuvant cholera toxin (CT) (or buffer in controls), sensitization and anaphylactic responses were determined. Gastrointestinal content was collected from the distal ileum, cecum, colon, and fecal pellets, and the bacterial diversity and composition was determined by deep sequencing of the 16S rRNA gene. SCFAs in gastrointestinal content supernatants were determined by gas chromatography.

RESULTS

The microbiota signatures were profoundly affected by allergen immunization. Ten operational taxonomic units (OTUs) were significantly different between immunized and control animals for at least one of the intestinal segments; eight of these OTUs belonged to the Clostridia class. Although consistent across all four gut segments, the colon showed the highest number of OTUs significantly associated with allergic immunization. SCFA levels in the cecum were also altered by immunization.

CONCLUSIONS

Allergen immunization with CT in the present food allergy model induced profound changes in the microbiome composition and SCFA production. The result suggests that the colon may be the most sensitive gut segment for investigating changes in the gut microbiome.

Mast Cells and Irritable Bowel Syndrome: From the Bench to the Bedside

Irritable bowel syndrome (IBS) is traditionally defined as a functional disorder since it lacks demonstrable pathological abnormalities. However, in recent years, low grade inflammatory infiltration, often rich in mast cells, in both the small and large bowel, has been observed in some patients with IBS. The close association of mast cells with major intestinal functions, such as epithelial secretion and permeability, neuroimmune interactions, visceral sensation, and peristalsis, makes researchers and gastroenterologists to focus attention on the key roles of mast cells in the pathogenesis of IBS. Numerous studies have been carried out to identify the mechanisms in the development, infiltration, activation, and degranulation of intestinal mast cells, as well as the actions of mast cells in the processes of mucosal barrier disruption, mucosal immune dysregulation, visceral hypersensitivity, dysmotility, and local and central stress in IBS. Moreover, therapies targeting mast cells, such as mast cell stabilizers (cromoglycate and ketotifen) and antagonists of histamine and serotonin receptors, have been tried in IBS patients, and have partially exhibited considerable efficacy. This review focuses on recent advances in the role of mast cells in IBS, with particular emphasis on bridging experimental data with clinical therapeutics for IBS patients.