Project description:Exclusively breast-fed infants can exhibit clear signs of IgE or non IgE-mediated cow’s milk allergy. The definite characterization of dietary cow’s milk proteins (CMP) that survive the maternal digestive tract to be absorbed into the bloodstream and secreted into breast milk remains missing. The aim of this study was to assess the occurrence of CMP-derived peptides in breast milk, using antibody-independent methods. Using high performance liquid chromatography-high resolution mass spectrometry in blinded assays, we identified 11 cow’s milk-derived peptides, including two β-lactoglobulin (2 out 6 samples) and one αs1-casein (1 out 6 samples) fragments, in breast milk from mothers receiving a cup of bovine milk daily. The β-lactoglobulin (β-Lg) fragments, namely f42-54 and f42-57, were absent in milk from mothers who observed a strict dairy-free diet (6 samples). In contrast, neither intact nor hydrolyzed β-Lg was detected by Western blot or competitive ELISA tests. CMP-derived peptides rather than intact CMP may sensitize or elicit allergic responses in the neonate through mother’s milk. Immunologically active peptides from the maternal diet could be involved in priming the newborn’s immune system to drive tolerogenic response in neonates and infants.
Project description:Exclusively breast-fed infants can exhibit clear signs of IgE or non IgE-mediated cow’s milk allergy. The definite characterization of dietary cow’s milk proteins (CMP) that survive the maternal digestive tract to be absorbed into the bloodstream and secreted into breast milk remains missing. The aim of this study was to assess the occurrence of CMP-derived peptides in breast milk, using antibody-independent methods. Using high performance liquid chromatography-high resolution mass spectrometry in blinded assays, we identified 11 cow’s milk-derived peptides, including two ?-lactoglobulin (2 out 6 samples) and one ?s1-casein (1 out 6 samples) fragments, in breast milk from mothers receiving a cup of bovine milk daily. The ?-lactoglobulin (?-Lg) fragments, namely f42-54 and f42-57, were absent in milk from mothers who observed a strict dairy-free diet (6 samples). In contrast, neither intact nor hydrolyzed ?-Lg was detected by Western blot or competitive ELISA tests. CMP-derived peptides rather than intact CMP may sensitize or elicit allergic responses in the neonate through mother’s milk. Immunologically active peptides from the maternal diet could be involved in priming the newborn’s immune system to drive tolerogenic response in neonates and infants.
Project description:In this study, we quantitated the disappearance of intact HMOs and characterized the glycan digestion products in the gut that are produced by the action of microbial enzymes on HMOs and glycoconjugates from breast milk. Oligosaccharides from fecal samples of exclusively breast-fed infants were extracted and profiled using nanoLC-MS. Intact HMOs were found in the fecal samples, additionally, other oligosaccharides were found corresponding to degraded HMOs and non-HMO based compounds. The latter compounds were fragments of N-glycans released through the cleavage of the linkage to the asparagine residue and through cleavage of the chitobiose core of the N-glycan.
Project description:Over the course of milk digestion, native milk proteases and infant digestive proteases fragment intact proteins into peptides with potential bioactivity. This study investigated the release of peptides over three hours of gastric digestion in 14 preterm infant sample sets. The peptide content was extracted and analyzed from milk and gastric samples via Orbitrap tandem mass spectrometry. The relative ion intensity (abundance) and count of peptides in each sample were compared over time and between infants fed milk fortified with bovine milk fortifier and infants fed unfortified milk. Bioactivity of the identified peptides was predicted by sequence homology to known bioactive milk peptides. Both total and bioactive peptide abundance and count continuously increased over three hours of gastric digestion. After accounting for infant weight, length, and post-conceptual age, fortification of milk limited the release of peptides from human milk proteins. Peptides that survived further gastric digestion after their initial release were structurally more similar to bioactive peptides than non-surviving peptides. This work is the first to provide a comprehensive profile of milk peptides released during gastric digestion over time, which is an essential step in determining which peptides are most likely to be biologically relevant in the infant.
Project description:Diet-microbe interactions play a crucial role in infant development and modulation of the early-life microbiota. The genus Bifidobacterium dominates the breast-fed infant gut, with strains of B. longum subsp. longum (B. longum) and B. longum subsp. infantis (B. infantis) particularly prevalent within the early-life microbiota. Although, transition from milk to a more diversified diet later in infancy initiates a shift to a more complex microbiome, with concurrent reductions in Bifidobacterium abundance, specific strains of B. longum may persist in individual hosts for prolonged periods of time. Here, we sought to investigate the adaptation of B. longum to the changing infant diet during the early-life developmental window. Genomic characterisation of 75 strains isolated from nine either exclusively breast- or formula-fed infants in the first 18 months of their lives revealed subspecies- and strain-specific intra-individual genomic diversity with respect to glycosyl hydrolase families and enzymes, which corresponded to different dietary stages. Complementary phenotypic growth studies indicated strain-specific differences in human milk oligosaccharide and plant carbohydrate utilisation profiles between and within individual infants, while proteomic profiling identified proteins involved in metabolism of selected carbohydrates. Our results indicate a strong link between infant diet and B. longum subspecies/strain genomic and carbohydrate utilisation diversity, which aligns with a changing nutritional environment i.e. moving from breast milk to a solid food diet. These data provide additional insights into possible mechanisms responsible for the competitive advantage of this bifidobacterial species and their long-term persistence in a single host and may contribute to rational development of new dietary therapies for this important development window.
Project description:Examining the relationship between maternal body size, gestational glucose tolerance status, mode of delivery and ethnicity on mother's milk microbiota at three months post-partum
Project description:Breastfeeding is thought to influence the immune system development of infants and may even affect various immunological responses later in life. Breast milk provides a rich source of early nutrition for the growth and developmental of infants. However, the presence of certain compounds in breast milk related to an unhealthy lifestyle or the diet of lactating mothers may negatively impact infants6. Based on a cohort study, we found that the composition of mother’s milk containing high amount of long-chain saturated fatty acids (LCSFAs) was related to a higher incidence of atopic dermatitis (AD) in children. Similarly, a mouse model in which breastfed offspring were fed milk high in LCSFAs also resulted in AD onset later in life. We showed that LCSFAs are damage-associated molecular patterns, which initiate a series of inflammatory events in the gut involving type 3 innate lymphoid cells (ILC3s). A remarkable increase in inflammatory ILC3s was observed in the gut, and the migration of these ILC3s to the skin contributed to the pathogenesis of AD. Gene expression analysis of ILC3s isolated from the gut revealed up-regulation of genes that increase ILC3s and chemokines, which may play a role in ILC migration to the skin. Even in the absence of adaptive immunity, Rag1 knockout mice fed a high-LCSFA milk diet developed eczema, accompanied by increased gut ILC3s. Here, we propose that early exposure to LCSFAs in infants may affect the balance of intestinal innate immunity, inducing a highly inflammatory environment with the proliferation of ILC3s and production of interleukin-17 and interleukin-22, which are attributed to the pathogenesis of AD.