Silent messengers in the nano-world: Harnessing extracellular vesicles as theranostic tools for neonatal surgical conditions

Extracellular vesicles (EVs) are lipid bilayer-enclosed nanoparticles secreted by all cells that mediate intercellular communication by transferring proteins, lipids, and nucleic acids. Among their cargo, microRNAs are key post-transcriptional regulators of organogenesis. In fetal lung development, EV-mediated signaling is essential for the coordination of epithelial, mesenchymal, endothelial, and immune cells. In congenital diaphragmatic hernia (CDH), disruption of these interactions leads to pulmonary hypoplasia and pulmonary hypertension, the primary causes of morbidity and mortality. Amniotic fluid stem cell-derived EVs (AFSC-EVs) have emerged as a promising cell-free therapy to restore this impaired communication. In rodent, rabbit, and human models of pulmonary hypoplasia, AFSC-EV administration rescues branching morphogenesis, promotes epithelial and mesenchymal differentiation, and attenuates macrophage-driven inflammation. Cargo analyses identified enrichment of the miR-17∼92 cluster, whose regulatory role in branching and progenitor differentiation is indispensable for normal lung growth. Mechanistic studies demonstrated that RNA degradation or selective inhibition of these microRNAs abolished the regenerative effects, underscoring the central role of EV small RNAs. Single-nucleus RNA sequencing confirmed restoration of transcriptional programs in AFSC-EV-treated lungs to profiles resembling healthy controls. Together, these findings establish AFSC-EVs as potent mediators of fetal lung repair in experimental models. Beyond CDH, EVs represent a promising theranostic strategy for pediatric surgical conditions in which restoration of intercellular communication is critical.