Protein and Lipid Content of Milk Extracellular Vesicles: A Comparative Overview

The characterization of the protein and lipid cargo of milk extracellular vesicles from different mammal species is crucial for understanding their biogenesis and biological functions, as well as for a comprehensive description of the nutritional aspects of animal milk for human diet. In fact, milk EVs have been reported to possess relevant biological effects, but the molecules/biochemical pathways underlying these effects have been poorly investigated. The biochemical characterization is an important initial step for the potential therapeutic and diagnostic use of natural or modified milk EVs. The number of studies analysing the protein and lipid composition of milk EVs is limited compared to that investigating the nucleic acid cargo. Here, we revised the literature regarding the protein and lipid content of milk EVs. Until now, most investigations have shown that the biochemical cargo of EVs is different with respect to that of other milk fractions. In addition, even if these studies derived mostly from bovine and human milk EVs, comparison between milk EVs from different animal species and milk EVs biochemical composition changes due to different factors including lactation stages and health status is also beginning to be reported.