Dynamic Variations in Endogenous Peptides in Chinese Human Milk Across Lactation and Geographical Regions

TL;DR

This study analyzed endogenous peptides in Chinese human milk across lactation stages and regions, revealing variations linked to immunity and infant growth.

Contribution

The study identifies dynamic peptide profiles in human milk and links them to maternal diet and infant growth parameters for the first time in a Chinese cohort.

Findings

Peptides from PIGR were more abundant in early lactation, offering higher antimicrobial activity.

Lanzhou milk showed higher levels of CASB and BTN1A1 peptides compared to other regions.

Maternal fat intake correlated with specific antimicrobial peptides, while some peptides inversely correlated with infant growth.

Abstract

Background/Objectives: This study characterized the endogenous peptide profile of human milk from a Chinese multicenter cohort (n = 200 mothers) using the Orbitrap Fusion Lumos LC-MS/MS. Methods: Samples were collected across different lactation stages (2 and 6 months postpartum) and seven geographic regions (Beijing, Chengdu, Guangzhou, Jinhua, Lanzhou, Weihai, and Zhengzhou). Results: In total, 6960 peptides derived from 621 proteins were identified. Peptides from the polymeric immunoglobulin receptor (PIGR) were more abundant in the 2nd month than the 6th month, providing a high antimicrobial activity and immune functions for the infants. Moreover, region-specific variations were observed, with milk from Lanzhou exhibiting significantly higher levels of β-casein (CASB) and butyrophilin subfamily 1 member A1 (BTN1A1) peptides compared to other cities. Conclusions: Furthermore, maternal dietary intake of oils and total fat correlated positively with the intensity of specific antimicrobial peptides, including CASB_199–216, CASB_200–226, and CASB_201–226. Infant growth parameters were inversely correlated with several antimicrobial peptides, although CASB_200–225 demonstrated positive associations. These findings offer novel insights into the dynamics of endogenous peptides in human milk and may guide breastfeeding recommendations and infant formula design.

Figures