Background There is increasing evidence linking alterations of the gut microbial composition during early infancy to the development of atopic diseases and asthma. However, few studies have addressed the association of dysbiotic gut microbiota with allergic reactions through evaluation of feces in young children with allergic airway diseases. Methods We sought to evaluate relationships among gut microbiota, total fecal immunoglobulin E (IgE) levels, serum allergic sensitization, and their relevance to childhood allergic rhinitis and asthma. Microbial composition and diversity were analyzed with Illumina-based 16S rRNA gene sequencing of 89 stool samples collected from children with asthma (n = 35) and allergic rhinitis (n = 28), and from healthy controls (n = 26). Data analysis was performed using Quantitative Insights into Microbial Ecology (QIIME) software. Results A significantly lower abundance of organisms of the phylum Firmicutes were found in children with asthma and allergic rhinitis than in the healthy controls. Relatively lower Chao1 and Shannon indices were also found in children with allergic airway diseases but without any significant difference. Total fecal IgE levels in early childhood were strongly correlated with serum D. pteronyssinus - and D. farinae -specific IgE but not with food-specific IgE levels. In comparison with healthy controls, the genus Dorea was less abundant and negatively correlated with total fecal IgE levels in children with rhinitis, whereas the genus Clostridium was abundant and positively correlated with fecal IgE levels in children with asthma. Conclusions An interaction between particular subsets of gut microbial dysbiosis and IgE-mediated responses to allergens may contribute to the susceptibility to allergic rhinitis and asthma in early childhood.

ObjectivesA detailed understanding of the metabolic processes governing rapid growth in early life is still lacking. The aim of this study was to investigate the age-related metabolic changes in healthy children throughout early childhood.MethodsHealthy children from a birth cohort were enrolled in this study from birth through 4 years of age. Urinary metabolites were assessed at 6 months, and 1, 2, 3, and 4 yr of age by using 1H-nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate statistical analysis including principal components analysis (PCA) and partial least-squares discriminant analysis (PLS-DA). Metabolic pathway analysis was performed using the MetPA web tool.ResultsA total of 105 urine samples from 30 healthy children were collected and analyzed. Metabolites contributing to the discrimination between age groups were identified by using supervised PLS-DA (Q2 = 0.60; R2 = 0.66). A significantly higher urinary trimethylamine N-oxide (TMAO) and betaine level was found in children aged 6 months. Urinary glycine and glutamine levels declined significantly after 6 months of age and there was a concomitant compensatory increase in urinary creatine and creatinine. Metabolic pathway analysis using MetPA revealed similar nitrogen metabolism associated energy production across all ages assessed. Pathways associated with amino acid metabolism were significantly different between infants aged 6 months and 1 year, whereas pathways associated with carbohydrate metabolism were significantly different between children at ages 2 and 3 years.ConclusionsUrine metabolomics ideally represents dynamic metabolic changes across age. Urinary metabolic profiles change significantly within the first year of life, which can potentially provide crucial information about infant nutrition and growth.

Background A comprehensive metabolomics‐based approach to address the impact of specific gut microbiota on allergen sensitization for childhood rhinitis and asthma is still lacking. Methods Eighty‐five children with rhinitis (n = 27) and with asthma (n = 34) and healthy controls (n = 24) were enrolled. Fecal metabolomic analysis with 1H‐nuclear magnetic resonance (NMR) spectroscopy and microbiome composition analysis by bacterial 16S rRNA sequencing were performed. An integrative analysis of their associations with allergen‐specific IgE levels for allergic rhinitis and asthma was also assessed. Results Amino acid, β‐alanine, and butanoate were the predominant metabolic pathways in the gut. Among them, amino acid metabolism was negatively correlated with the phylum Firmicutes, which was significantly reduced in children with rhinitis and asthma. Levels of histidine and butyrate metabolites were significantly reduced in children with rhinitis (P = 0.029) and asthma (P = 0.009), respectively. In children with asthma, a reduction in butyrate‐producing bacteria, including Faecalibacterium and Roseburia spp., and an increase in Clostridium spp. were negatively correlated with fecal amino acids and butyrate, respectively (P < 0.01). Increased Escherichia spp. accompanied by increased β‐alanine and 4‐hydroxybutyrate appeared to reduce butyrate production. Low fecal butyrate was significantly associated with increased total serum and mite allergen–specific IgE levels in children with asthma (P < 0.05). Conclusion A reduced fecal butyrate is associated with increased mite‐specific IgE levels and the risk of asthma in early childhood. Fecal β‐alanine could be a specific biomarker connecting the metabolic dysbiosis of gut microbiota, Clostridium and Escherichia spp., in childhood asthma.