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Differences in human milk peptide release along the gastrointestinal tract between preterm and term infants
Robert L Beverly1, Robert K Huston2, Andi M Markell2
1School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, USA.
Insights
Preterm infants show higher total milk peptide release in the stomach compared to term infants. However, term infants release more specific bioactive peptides, indicating different digestion patterns in the infant gastrointestinal tract.
Area of Science:
- Neonatal nutrition
- Gastrointestinal physiology
- Proteomics
Background:
- Infants born preterm have underdeveloped gastrointestinal tracts, impacting human milk protein digestion.
- Bioactive peptides from human milk digestion may benefit infant development.
- The effect of prematurity on peptide release throughout the infant gastrointestinal tract is not well understood.
Purpose of the Study:
- To compare milk peptide release from milk to stomach to stool between preterm and term infants.
- To investigate how prematurity influences total and bioactive peptide profiles in the infant gut.
Main Methods:
- Milk, gastric, and stool samples were collected from preterm (early and late) and term infants.
- Milk peptides were extracted and identified using Orbitrap mass spectrometry.
- Peptide abundance and count were compared across digestion stages and infant groups.
Main Results:
- Total milk peptide count and abundance increased from milk to stomach, then decreased in stool, with similar patterns between groups in milk and stool.
- Preterm infants in early collection showed significantly higher gastric peptide abundance and count.
- Term infants had higher abundance of a specific antimicrobial peptide in gastric samples compared to preterm infants.
Conclusions:
- Preterm and term infants exhibit distinct milk protein digestion patterns in their gastrointestinal tracts.
- While preterm infants release more total peptides in the stomach, term infants release specific bioactive peptides at higher levels.
- A conserved C-terminal region of beta-casein releases antimicrobial peptides throughout digestion in infants.
Background & Aims:
Preterm infants are born with a gastrointestinal tract insufficiently developed to digesting large quantities of human milk proteins. Peptides released from the digestion of human milk proteins have been identified with bioactivities that may be beneficial to the developing infant. However, it is unknown how prematurity affects total and bioactive peptide release along the gastrointestinal tract. The aim of this study was to compare milk peptide release from milk to stomach to stool between preterm and term infants.
Methods:
Milk, gastric, and stool samples were collected from preterm infants as early collection (days 8 and 9 of life) and late collection (days 21 and 22 of life), and from term infants as early collection. Milk peptides were extracted from the samples and identified using Orbitrap mass spectrometry. Peptide abundance and count were compared across digestion and between the three infant groups at each stage of digestion.
Results:
Total milk peptide count and abundance increased from milk to stomach then decreased in stool. Total peptide release was similar among the three infant groups for milk and stool samples. In the stomach, preterm early collection had significantly higher peptide abundance and count than the other two groups. Patterns for peptide release from individual milk proteins were distinct from total peptide release both across digestion and among the infant groups. When analyzing single peptides, term early collection gastric samples had significantly higher peptide abundance than preterm early collection for a known antimicrobial peptide, QELLLNPTHQIYPVTQPLAPVHNPISV.
Conclusions:
Preterm and term infants digest milk proteins differently along their gastrointestinal tracts. While preterm infants released more total peptides in the stomach, term infants released specific bioactive peptides at higher abundance. We identified a region at the C-terminus of β-casein that is conserved from milk through stool and from which are released known and potential antimicrobial peptides.
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