Lipidomic Analysis of Extracellular Vesicles in Human Breast Milk and Comparison with Milk Polar Lipids Using...

Milk-derived extracellular vesicles (EVs) show potential applications as nanomedicine; however, their membrane lipids are not fully studied. Herein, we present the lipidomic analysis of the extracted EVs and milk fat globules (MFGs) from human breast milk using ultraperformance supercritical fluid chromatography combined with quadrupole time-of-flight mass spectrometry. A total of 11 lipid species, including glycerophospholipids, sphingomyelin (SM), ceramide (Cer), and cholesterol (CHOL), and 182 molecular species were identified and quantified. EVs in human breast milk present ∼4.4% of total polar lipids, while the remaining lipids come from MFGs. Lipids in EVs are rich in CHOL, SM, phosphatidylcholine, and phosphatidylethanolamine and are stable during lactational stages. In human breast milk, EVs and MFGs have a similar CHOL/SM molar ratio (∼6). Membrane lipids in EVs have a low unsaturation degree and a high content of long-chain saturated fatty acids 24:1 n-9. The unique membrane lipid composition of human milk-derived EVs compared to MFGs can be used to study the molecular mechanism of their mRNA delivery in the infant gastrointestinal tract.