Bacterial extracellular vesicles: An emerging postbiotic

Our growing appreciation of the functional significance of the human microbiota in health and disease has triggered a marked interest in bacterial-derived extracellular vesicles (bEVs). In recent years, bEVs have been found to offer physiological benefits to the host by providing diverse bioactivity. Following the recent definition of postbiotics as a preparation of inanimate microorganisms and/or their components that confer a health benefit on the host, bEVs could serve as potential novel postbiotics. This review provides an overview of the biology of bEVs, evidence for their health benefits, and possible molecular pathways involved in their health-promoting effects, as well as perspectives for applications in foods and pharmaceuticals. Preclinical evidence has shown that bEVs confer diverse health-promoting functions to the intestinal local and extraintestinal organs, including immunomodulatory, anti-obesogenic, angiogenesis and osteogenesis, barrier tightening and cancer cell apoptosis. Although the exact mechanisms have not been entirely elucidated, this evidence demonstrates that bEVs may contribute to host health by regulating specific physiological functions and appear to be promising candidates as novel postbiotics.