Key roles of milk-derived extracellular vesicles in intestinal tract, with special emphasis on microRNAs in extracellular vesicles.

Studies have indicated that milk extracellular vesicles (EVs) are resistant to both the enzymatic activity of digestive enzymes and the acidic conditions common in the gastrointestinal tract. Thus, the intestinal tract efficiently absorbs and uses these EVs. There is mounting evidence in recent years that microRNAs (miRNAs) found in EVs derived from milk are essential for the intestinal prebiotic effect through target gene regulation. In this paper, we summarized the sources, biosynthetic processes, cargos, and the factors affecting milk-derived EVs. Furthermore, with particular attention to the potential communication mechanism of milk EVs in intestinal target cell receptors, including recognizing and binding to the surface of intestinal receptor cells, internalization of intestinal receptor cell uptake, and cargos acting on intestinal receptor cells. Especially, we also explored the role of milk EVs in several aspects of intestinal health, such as the immunological homeostasis, intestinal barrier, intestinal injury, inflammatory bowel disease, necrotizing enterocolitis, intestinal malignancy, and harm to other organs connected to the intestine. We expected to use milk-derived EVs or miRNAs as new dietary additives and functional regulatory factors. In the future, we will gain more knowledge about the substantial impact of EVs derived from milk on human intestines and other health-related matters.