Administration of Extracellular Vesicles From Donor Human Milk in Preterm Infants

Human milk is the optimal source of nutrition for infants, providing essential nutrients and bioactive components that promote growth and development. Very preterm infants (\<32 weeks gestation) are particularly vulnerable to feeding intolerance, impaired growth, and severe complications such as necrotizing enterocolitis (NEC). When a mother's own milk is insufficient or unavailable, pasteurized donor human milk (DHM) is the recommended alternative. Extracellular vesicles (EVs) are nanosized particles naturally present in human milk that carry proteins, lipids, and nucleic acids involved in cell signaling, intestinal maturation, immune regulation, and neurodevelopment. Preclinical studies suggest that milk-derived EVs may reduce inflammation and support gut and brain development, but their role in clinical outcomes for very preterm infants has not yet been established. The AdVEMPrem study (PI23/00202, ISCIII) is a prospective, single-arm pilot trial designed to evaluate the tolerance and safety of DHM-derived EV supplementation in very preterm infants. All enrolled infants will receive oral EV supplementation during hospitalization in the Neonatal Intensive Care Unit. Protocols for isolation and quality control of DHM-EVs will be established to ensure reproducible yields. The biochemical composition of milk and EVs will be characterized for product characterization and exploratory analyses, with emphasis on lipid profiles and functional properties. These analyses are not participant-level outcome measures. Clinical, nutritional, and developmental parameters will be monitored during the neonatal period, alongside biomarkers of redox balance and oxidative/nitrosative stress. Long-term follow-up will assess sustained effects on growth and neurodevelopmental trajectories. Findings from this pilot study will provide foundational evidence for the potential of milk-derived EVs as a safe nutritional strategy to prevent NEC and improve outcomes in preterm infants. Results will inform the design of larger multicenter trials and may contribute to the development of standardized EV-based supplements or analogues from alternative sources, thereby addressing variability in donor milk composition. Ultimately, access to an efficient and safe nutritional supplement could reduce the incidence of NEC, improve infant and family outcomes, and deliver socio-economic and ecological benefits.