LC-MS/MS-Based Peptide Mapping Explores the Contribution of Human Milk to Breast Milk Jaundice

Background: Breast milk jaundice (BMJ) is prevalent in breastfed newborns. Regarding the relationship between breastfeeding and BMJ, researchers have focused on certain components in breast milk. Peptides, low-molecular-weight fractions of proteins, have been identified more than 300 in breast milk. Many of these peptides are bioactive substances involved in regulating phys-iological and pathological processes. In the present study, we aim to further characterize the peptidome of BMJ and healthy neonates by LC-MS/MS (Liquid chromatography tandem mass spectrometry) analysis and attempt to quantify whether there are differences in breast milk peptide expression between the two groups of neonates to provide a basis for investigating the pathogenesis of BMJ.Methods: Six mother-and-child dyads were recruited into our study. Three newborns were diagnosed with BMJ, and the re-maining were healthy. LC-MS/MS analysis was adopted to access the breast milk peptide profile. Gene Ontology (GO) analysis was applied to predict possible functions of the differentially expressed peptides. Results: After removing the interference of other macromolecular proteins, 245 peptides were identified, with 30 differentially expressed peptides, including 11 upregulated and 19 downregulated peptides. GO analysis demonstrated that the possible func-tions of the differentially expressed peptides were closely relevant to BMJ pathogenesis.Conclusions: This study implied that changes in the breast milk peptide profile may be related to BMJ development, which may offer new insight for exploring the formation of BMJ.