Impairment of intestinal barrier associated with the alternation of intestinal flora and its metabolites in cow's milk protein allergy

In vitro assessment of the effect of Porphyra haitanensis polysaccharides on the intestinal flora of allergic mice

This study systematically investigated the modulatory effects of Porphyra haitanensis polysaccharides (PHP) and its two P. haitanensis polysaccharide components (PHP40 and PHP80) on gut microbiota in ovalbumin (OVA)-sensitized mice via in vitro fermentation. PHP40 and PHP80 exhibited sulfate contents of 5.94 ± 0.05 % and 11.72 ± 0.03 %, respectively, with galactose and glucose as dominant monosaccharides. The different polysaccharide components had different effects on the aforementioned changes in the species composition and structure of the gut microbiota in allergic mice, with distinct dominant microbial profiles across groups. PHP could promote Bacillus and Enterococcus proliferation while inhibiting Staphylococcus. PHP40 and PHP80 could promote Enterococcus and Enterobacter growth but suppressed Staphylococcus and Bacillus. Functional prediction indicated PHP significantly improved galactose metabolism and primary/secondary bile acid biosynthesis, potentially alleviating allergic responses.

Gut microbiome features in pediatric food allergy: a scoping review

Increasing evidence suggests that alterations in the gut microbiome (GM) play a pivotal role in the pathogenesis of pediatric food allergy (FA). This scoping review analyzes the current evidence on GM features associated with pediatric FAs and highlights the importance of the GM as a potential target of intervention for preventing and treating this common condition in the pediatric age. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we searched PubMed and Embase using the keywords (gut microbiome OR dysbiosis OR gut microbiota OR microbiome signatures) AND (food allergy OR IgE-mediated food allergy OR food protein-induced allergic proctocolitis OR food protein-induced enterocolitis OR non-IgE food allergy OR cow milk allergy OR hen egg allergy OR peanut allergy OR fish allergy OR shellfish allergy OR tree nut allergy OR soy allergy OR wheat allergy OR rice allergy OR food sensitization). We included 34 studies reporting alterations in the GM in children affected by FA compared with healthy controls. The GM in pediatric FAs is characterized by a higher abundance of harmful microorganisms (e.g., Enterobacteriaceae, Clostridium sensu stricto, Ruminococcus gnavus, and Blautia spp.) and lower abundance of beneficial bacteria (e.g., Bifidobacteriaceae, Lactobacillaceae, some Bacteroides species). Moreover, we provide an overview of the mechanisms of action elicited by these bacterial species in regulating immune tolerance and of the main environmental factors that can modulate the composition and function of the GM in early life. Altogether, these data improve our knowledge of the pathogenesis of FA and can open the way to innovative diagnostic, preventive, and therapeutic strategies for managing these conditions.

Specific Gut Microbiome Signatures in Children with Cow's Milk Allergy

Although gut dysbiosis is associated with cow's milk allergy (CMA), causality remains uncertain. This study aimed to identify specific bacterial signatures that influence the development and outcome of the disease. We also investigated the effect of hypoallergenic formula (HF) consumption on the gut microbiome of milk-allergic children. 16S rRNA amplicon sequencing was applied to characterize the gut microbiome of 32 milk-allergic children aged 5-12 years and 36 age-matched healthy controls. We showed that the gut microbiome of children with CMA differed significantly from that of healthy children, regardless of whether they consumed cow's milk. Compared to that of healthy cow's milk consumers, it was depleted in Bifidobacterium, Coprococcus catus, Monoglobus, and Lachnospiraceae GCA-900066575, while being enriched in Oscillibacter valericigenes, Negativibacillus massiliensis, and three genera of the Ruminococcaceae family. Of these, only the Ruminococcaceae taxa were also enriched in healthy children not consuming cow's milk. Furthermore, the gut microbiome of children who developed tolerance and had received an HF was similar to that of healthy children, whereas that of children who had not received an HF was significantly different. Our results demonstrate that specific gut microbiome signatures are associated with CMA, which differ from those of dietary milk elimination. Moreover, HF consumption affects the gut microbiome of children who develop tolerance.

The alleviated symptoms in ovalbumin‐allergic mice treated with selenium‐enriched tea polysaccharide by modulation of intestinal flora and gut metabolites

Ovalbumin (OVA) in egg is one of the predominant causes of food allergy around the world. In the present study, the alleviating effect of selenium‐enriched tea polysaccharide (Se‐TPS) on OVA allergy was evaluated, and the underlying mechanistic insights were investigated. Se‐TPS significantly alleviated the clinical manifestations and diarrhea of allergic mice, accelerated the recovery of jejunal injury, and decreased the immune organ index. Meanwhile, Se‐TPS decreased the levels of immunoglobulin E (IgE), histamine, and IL‐4 in serum, increased the levels of IFN‐γ, and promoted the balance of Th1/Th2 cells. Furthermore, the intervention of Se‐TPS reshaped the gut microbiota structure of OVA‐allergic mice. Se‐TPS increased the abundance of Lachnospiraceae_NK4A136_group, unclassified_f_Lachnospiraceae, and Alistipes, whereas decreased the Faecalibaculum abundance. Analysis of intestinal metabolites showed that Se‐TPS treatment caused a significant increase in homocitrulline and 7a‐hydroxyandrost‐4‐ene‐3,17‐dione levels. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment results indicated that Se‐TPS treatment may alleviate allergic symptoms by enhancing the anti‐inflammatory ability of OVA‐allergic mice through neuroimmunity.

Alterations in the gut microbiota of toddlers with cow milk protein allergy treated with a partially hydrolyzed formula containing synbiotics: A nonrandomized controlled interventional study

Formulas containing intact cow milk protein are appropriate alternatives when human milk (HM) is not feasible. However, for babies with a physician-diagnosed cow milk protein allergy (CMPA), hydrolyzed formulas are needed. We conducted a 3-month, open-label, nonrandomized concurrent controlled trial (ChiCTR2100046909) between June 2021 and October 2022 in Qingdao City, China. In this study, CMPA toddlers were fed with a partially hydrolyzed formula containing synbiotics (pHF, n = 43) and compared with healthy toddlers fed a regular intact protein formula (IF, n = 45) or HM (n = 21). The primary endpoint was weight gain; the secondary endpoints were changes in body length and head circumference of both CMPA and healthy toddlers after 3-month feeding; and the exploratory outcomes were changes in gut microbiota composition. After 3 months, there were no significant group differences for length-for-age, weight-for-age, or head circumference-for-age Z scores. In the gut microbiota, pHF feeding increased its richness and diversity, similar to those of IF-fed and HM-fed healthy toddlers. Compared with healthy toddlers, the toddlers with CMPA showed an increased abundance of phylum Bacteroidota, Firmicutes, class Clostridia, and Bacteroidia, and a decreased abundance of class Negativicutes, while pHF feeding partly eliminated these original differences. Moreover, pHF feeding increased the abundance of short-chain fatty acid producers. Our data suggested that this pHF partly simulated the beneficial effects of HM and shifted the gut microbiota of toddlers with CMPA toward that of healthy individuals. In conclusion, this synbiotic-containing pHF might be an appropriate alternative for toddlers with CMPA.