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:Human breast milk as part of late preterm infant study. Samples were extracted with ethanol and processed on a Bruker Daltonics maXis Impact and C18 RP-UPLC for untargeted metabolomic analysis. Positive polarity acquisition of LC-MS/MS.
Project description:91 preterm infant gut metaproteomes measured in technical duplicate using an eleven salt pulse 2D-LC-MS/MS method. Samples represent 17 preterm infants over the first several weeks of life, of which 6 preterm infants eventually developed necrotizing enterocolitis.
Project description:Hundreds of naturally occurring milk peptides have been found in term human milk. Whether there are differences between the levels of these peptides between term and preterm milk remains unknown. Premature milk is produced before complete maturation of the mammary gland and is under the influence of a different hormonal milieu, which could change enzymatic activity and protein expression within the mammary gland and result in an altered peptide profile. We employed nano-liquid chromatography tandem mass spectrometry to identify naturally occurring peptides in term and premature milks at multiple time-points across lactation and compare the abundances of these peptides. We found that preterm milks produced more unique peptide sequences than term milks on average (359 vs. 286). The peptides identified were searched for overlapping sequences with an in-house database of known functional peptides. Specifically, we found that both term and preterm milks contain peptides overlapping with known sequences with antimicrobial, opioid antagonist and immunomodulatory actions. We also compared the enzymes involved in degradation of both milks via bioinformatic analysis. This analysis reveals that plasmin is more active in preterm milk than term milk.
Project description:Human milk, the best enteral selection for a preterm infant, becomes altered during freezing and soluble free fatty acid is generated over time. Free fatty acids may form complexes, such as the oleic acid-bound protein called HAMLET (human α‐lactalbumin made lethal to tumor cells). We determined the in vitro biological activity of preterm human milk protein‐oleic complexes (HAMLET-like complexes) and tested the hypothesis that laboratory-synthesized HAMLET exhibits cytotoxicity in human immature epithelial intestinal cell culture. Thirty-four milk samples from 15 mothers of hospitalized preterm infants were donated over time. Milk fractions were tested repeatedly for FHs 74 Int and HIEC-6 fetal cell cytotoxicity, using a sensitive viability assay. Protein and fatty acid identities were confirmed by Western blot, high performance liquid chromatography, and mass spectrometry. Cytotoxicity of intestinal cells exposed to milk increased respective to milk storage time (p<0.001) and was associated with free oleic acid (p=0.009). Synthesized HAMLET was cytotoxic in cultures of both lines. Preterm milk samples killed most cells in culture after an average 54 days in frozen storage (95% C.I. 34-72 days). After prolonged storage time, preterm milk and HAMLET showed a degree of cytotoxicity to immature intestinal cells in culture. Protein was reduced 221 in 1 mM dithiothreitol and alkylated in 5.5 mM
Project description:Injury occurring during critical periods of development may have long-term effects on inflammatory responses. Periventricular leukomalacia (PVL) is the most common cause of cerebral palsy (CP) in preterm infant. Activated leukocytes are the main source of inflammatory cytokines that give rise to white matter damage and CP in preterm infant. Here, we tested the hypothesis that inflammation profiles as pathogenic mediators for the occurrence of PVL in the neonatal period may persist in preterm children with CP at school age. Five preterm children with PVL-induced CP and gestational age-matched five preterm children with normal neurodevelopment were recruited from follow up clinics. Proinflammatory gene expression in the PBMCs from preterm children were determined by Superarray PCR study.
Project description:Milk and milk products such as infant formula (IF) play a fundamental role in serving the nutritional needs of the developing infant. Extracellular vesicles (EVs) in human (HM) and cow’s milk (CM) contain molecular cargo such as proteins and micro(mi)RNA that serve as functional messengers between cells and may be of importance to infant health. Here, we have developed a pipeline using advanced proteomics and transcriptomics to enable cross-species comparison of milk and IF EVs. EVs from HM, CM and IF were subjected to data-independent acquisition mass spectrometry and RNA-seq. Differentially abundant proteins (143) and miRNAs (514) (false discovery rate < 0.01) were identified in HM and CM EVs, and CM EV proteins and miRNAs were conserved in IF EVs (~20-90%). We foresee this work to be used in large scale studies to determine biologically relevant species-specific differences in milk EVs that could be leveraged to improve IF products.
Project description:Injury occurring during critical periods of development may have long-term effects on inflammatory responses. Periventricular leukomalacia (PVL) is the most common cause of cerebral palsy (CP) in preterm infant. Activated leukocytes are the main source of inflammatory cytokines that give rise to white matter damage and CP in preterm infant. Here, we tested the hypothesis that inflammation profiles as pathogenic mediators for the occurrence of PVL in the neonatal period may persist in preterm children with CP at school age.
Project description:Very little is known about miRNAs found in breastmilk cells, which also reflect the cells of the lactating mammary epithelium. Our hypothesis is that breastmilk cells are richer in miRNA compared to other milk fractions, such as skim milk. Further, the effects of milk removal by the infant on milk cell miRNA content and/or composition have not been investigated. Breastmilk cells conserved higher miRNA content than previously published lipid and skim fractions of breastmilk as well as other known sources of miRNA in humans. Specifically, 1,467 known mature miRNAs were identified and a further 1996 novel miRNAs, of which 89 were highly expressed. As previously shown, post-feed milk contained more cells than pre-feed milk, and the same was observed for miRNA content. However, no statistically significant difference was found in the expression of the total known and novel miRNAs between pre- and post-feed milk (p=0.76), although 27 known miRNAs and 1 novel miRNA were higher expressed in post-feed milk. As expected, samples richer in viable cells contained more known miRNAs (p = 0.01). Functional analysis of the top 10 most highly expressed known miRNAs showed that they may be potentially involved in crucial roles for the infant, including body fluid balance, thirst, appetite, immune responses, and development. In conclusion, breastmilk is highly rich in miRNA which may play important functions in the breastfed infant and the lactating breast. Milk removal by the infant can influence the total miRNA content of breastmilk, similar to its cell and fat content, but the miRNA composition remains constant
Project description:Preterm neonates are susceptible to gastrointestinal (GI) disorders such as necrotizing enterocolitis (NEC). Maternal milk, and especially colostrum, protects against NEC via growth promoting, immunomodulatory and antimicrobial factors. The fetal enteral diet, amniotic fluid (AF), contains similar bioactive components and we hypothesized that postnatal AF administration would reduce inflammatory responses and NEC in preterm neonates. Thirty preterm pigs (92% gestation) were delivered by caesarean section and fed total parental nutrition (TPN) for 48 h followed by enteral porcine colostrum (COLOS, n=7), infant formula (FORM, n=13) or formula + porcine AF (AF, n=10). Using a previously validated model of NEC in preterm pigs, we determined the structural, functional, microbiological and immunological responses to AF when administered prior to and after introduction of a suboptimal enteral formula diet. Keywords: Healthy versus inflammed tissues in relation to necrotizing enterocolitis