Effects of bovine milk-derived extracellular vesicles on a 3D intestinal stromal compartment

Milk is an essential component of the diet. Among its diverse molecular constituents, it contains nanoscale entities, known as extracellular vesicles (EVs), which play a pivotal role in intercellular communication. In particular, milk-derived EVs (MEVs) influence intestinal homeostasis by mitigating inflammatory responses, modulating gut microbiota composition, and contributing to epithelial integrity preservation and restoration. Currently, there are no information regarding their impact on intestinal connective tissue. Here, we investigate bovine MEV effects on the porcine gut stromal compartment, exposing intestinal decellularized bio-scaffolds repopulated with primary intestinal stromal fibroblasts, to different MEV concentrations (106, 108, and 1010 particles/mL). We observed a dose-dependent effect of MEVs on stromal fibroblast proliferation rate at concentrations higher than 106 particles/mL. In addition, when MEVs were used to pre-condition the decellularized intestinal bio-scaffolds prior to cell repopulation, fibroblast growth was further boosted. Overall, these findings suggest that MEVs may play a significant role in promoting tissue remodeling and repair. This activity appears particularly relevant for enhancing intestinal homeostasis and resilience, as stromal fibroblasts contribute to the maintenance of gut integrity, barrier function, and immune balance. Moreover, the data here presented suggests the possibility of using MEVs to develop serum-free, chemically defined culture media for the generation of advanced three-dimensional (3D) models and intestinal artificial organs.