Peptidomics Analysis of Milk Protein-Derived Peptides Released over Time in the Preterm Infant Stomach

Abstract

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 3 h 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 3 h of gastric digestion. After accounting for infant weight, length, and postconceptual 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 nonsurviving 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. Data are available via ProteomeXchange with identifier PXD012192.

Quantitative Analysis of Antibody Survival across the Infant Digestive Tract Using Mass Spectrometry with Parallel Reaction Monitoring

“…These findings align with those of our previous studies of digestion via peptidomics, which indicated the continual release of peptides from human milk proteins over time in the infant stomach and, by implication, the continual degradation of intact milk proteins [ 45 ]. This finding also agrees with our previous work indicating that palivizumab is degraded by incubation in infant gastric and intestinal fluids (ex vivo digestion) [ 18 ].…”

Influence of Pasteurization and Storage on Dynamic In Vitro Gastric Digestion of Milk Proteins: Quantitative Insights Based on Peptidomics

“…The intensities of peptides from regions f169-179 and f195-211 in PM7d were significantly higher than those in other samples at the end of gastric digestion. In summary, more and higher intensities of peptides were identified from the regions (16-55, 95-110, and 195-210), which was consistent with previous works presenting peptidomics analyses of bovine and human milk protein-derived peptides during in vitro dynamic digestion or clinical trials [32,33]. Similar hydrolysis regions of α s1 -CN were observed in all of the samples at the end of gastric digestion, although differences in peptide profiles existed in different samples during 120 min of digestion.…”

“…Overall, κ-CN exhibited rapid hydrolysis at the initial stage of digestion and minor changes during subsequent digestion. Several regions (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(98)(99)(100)(101)(102)(103)(104)(105)(106)(107)(108)(109)(110)(111)(112)(113)(114), and 168-179) were found to be resistant to hydrolysis in all of the samples during digestion, suggesting that these regions were resistant to pepsin hydrolysis.…”

Racial and socioeconomic disparities in breast milk feedings in US neonatal intensive care units

“…40 Protective potential of MOM is not measured by milk composition alone. The interaction between MOM and infant may result in greater protection than is measured in the milk itself, with release of immunomodulatory and anti-infective peptides in the infant's stomach that exceed the number in the pre-fed MOM, 68 with higher peptide release in preterm MOM than term MOM. 46 Similarly, the interaction between MOM enzymes and the infant's saliva produce superoxide and hydrogen peroxide, which inhibit opportunistic pathogenic bacteria.…”