Extracellular Vesicles to Evaluate the Effects of Mesenchymal Stromal Cells in the Premature Lung

Abstract

Bronchopulmonary dysplasia (BPD), caused by disrupted lung development, is a common complication of prematurity without effective treatment. Mesenchymal stromal cells (MSCs) improve features of experimental BPD, such as lung function, structure, and inflammation. The HULC-1 trial assessed the safety of MSCs for BPD. Since MSC mechanisms in the premature lung remain unclear, we hypothesized that extracellular vesicles (EVs) might reflect MSC effects. We analyzed EVs from tracheal aspirates (TA) collected before and after MSC treatment using two flow cytometry methods: antibody-capture to identify cellular origin and single particle analysis to quantify EVs. TA-EVs primarily originated from lung epithelium and immune cells. After MSC administration, total TA-EVs increased threefold within 3–4 days, though EVs from specific cell types showed no significant change. This suggests the EV increase may not be cell-type-specific. These findings highlight TA-EVs as potential biomarkers for MSC treatment response in preterm infants, warranting further investigation.