Human milk small extracellular vesicles elicit changes in inflammatory response in infant human intestinal enteroids.

Human milk (HM) is the key nutritional source for infants and the most effective preventative approach against serious gastrointestinal inflammatory diseases like necrotizing enterocolitis (NEC) in preterm infants. Numerous studies in animal models indicate HM-derived small extracellular vesicles (HMEV) reduce severity of inflammation; however, data on human-specific models are limited. Isolated HMEV were characterized from early-HM (colostrum and transitional), mature-HM, and a combined, pasteurized donor bank-like HM sample (pool-); pool-HMEV retains a profile aligned with HMEV from both early- and mature-HM samples. Exposure to pool-HMEV initiates unique gene signatures associated with reduction of inflammation including NFkB-driven TNFα signaling in human intestinal enteroids (HIEs) established from neonates with intestinal atresia or NEC. Prior exposure of HIEs to pool-HMEV lowers the magnitude of EGTA- and TNF-induced barrier disruption. This foundational research demonstrates HMEVs cause transcriptional and functional changes to the human intestinal epithelium and will support future studies on HMEV-based therapeutics.