Milk Extracellular Vesicles enhance gut barrier function in vitro

Milk extracellular vesicles (EVs) are small particles present in milk. This study investigates the potential of bovine milk EVs and their cargo to modulate human gut barrier integrity and permeability using in vitro gut barrier models. Polarized Caco-2 monolayers were exposed to milk EVs, EV phospholipid and protein components (sphingomyelin, phosphatidylethanolamine, xanthine oxidase and cluster of differentiation 9), for 4 h. Milk EVs increased the concentration of tight junction proteins claudin-1 and occludin, while cluster of differentiation 9, xanthine oxidase and sphingomyelin increased junctional adhesion molecule 1, a tight junction protein (P < 0.05). Additionally, a Caco-2 model simulating a newborn gut barrier was utilized, to evaluate the effect of milk EVs on barrier maturity for this life stage. EVs increased barrier integrity and reduced paracellular permeability in this infant model faster than controls (P < 0.05). These findings suggest that milk EVs promote gut barrier health in vitro.