NPNT and bronchopulmonary dysplasia: The critical role of disordered vascular development in BPD and PH is well-recognized49 and prior studies have shown that MSC lung protective effects in BPD are in part mediated by pro-angiogenic factors, such as vascular endothelial growth factor (VEGF)50 and stromal-derived factor-1.51 In our current study, we also show that one of the key genes differentially expressed in hyperoxia-exposed WJ-MSC EVs treated rats was nephronectin, an extracellular matrix protein that is involved in tissue development and repair.