Peptides from the Intestinal Tract of Breast Milk-Fed Infants Have Antimicrobial and Bifidogenic Activity.

Robert L Beverly,Jiraporn Lueangsakulthai,David C Dallas,Brian P Scottoline,Prajna Woonnimani

doi:10.3390/ijms22052377

Robert L Beverly, Jiraporn Lueangsakulthai + Show 3 more

Open Access

https://doi.org/10.3390/ijms22052377

Copy DOI

Abstract

For bioactive milk peptides to be relevant to infant health, they must be released by gastrointestinal proteolysis and resist further proteolysis until they reach their site of activity. The intestinal tract is the likeliest site for most bioactivities, but it is currently unknown whether bioactive milk peptides are present therein. The purpose of the present study was to identify antimicrobial and bifidogenic peptides in the infant intestinal tract. Milk peptides were extracted from infant intestinal samples, and the activities of the bulk peptide extracts were determined by measuring growth of Escherichia coli, Staphylococcus aureus, and Bifidobacterium longum spp. infantis after incubation with serial dilutions. The peptide profiles of active and inactive samples were determined by peptidomics analysis and compared to identify candidate peptides for bioactivity testing. We extracted peptides from 29 intestinal samples collected from 16 infants. Five samples had antimicrobial activity against S. aureus and six samples had bifidogenic activity for B. infantis. We narrowed down a list of 6645 milk peptides to 11 candidate peptides for synthesis, of which 6 fully inhibited E. coli and S. aureus growth at concentrations of 2500 and 3000 µg/mL. This study provides evidence for the potential bioactivity of milk peptides in the infant intestinal tract.

Highlights

IntroductionCompared with infants born at full term, preterm infants are at heightened risk of developing infections such as sepsis [2] and necrotizing enterocolitis [3], with the infection risk increasing as gestational age at birth decreases [4,5,6]
Over 380,000 infants are born prematurely in the US each year [1]
Compared with infants born at full term, preterm infants are at heightened risk of developing infections such as sepsis [2] and necrotizing enterocolitis [3], with the infection risk increasing as gestational age at birth decreases [4,5,6]

Summary

Introduction

Compared with infants born at full term, preterm infants are at heightened risk of developing infections such as sepsis [2] and necrotizing enterocolitis [3], with the infection risk increasing as gestational age at birth decreases [4,5,6]. Due to their reduced development time in utero, preterm infants are often born with an underdeveloped gastrointestinal (GI) tract and innate immunity (reduced gastric acidity, looser tight junctions, and dysbiotic microbiome) that leave them susceptible to pathogens [7,8,9]. Though the causes and locations of infection are disparate among infants, the universal standard of care for risk reduction is early and dedicated enteral feeding with human milk, whether the mother’s or donor milk [17]

Objectives

Methods

Results

Conclusion