Date

Thursday 13 Mar 2025

Time

15:15 - 15:45

Location

BW018

Supervisor

Marco van Eijk

External supervisor

Robbert Rottier

Jury

Anne Wentink

Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting preterm infants, particularly those with extremely low birth weight (ELBW). Despite advances in neonatal care, BPD remains a major clinical challenge with no curative treatment available. One promising candidate is vitamin A (VA), which supports lung development and repair. While VA is currently administered intramuscularly, inhalation may offer a more effective, and less invasive alternative. However, inhalation could pose challenges and studying BPD requires human in vitro models that go beyond hyperoxia-induced injury and embrace the multifactorial nature of the disease. This study explores VA nebulization in advanced human in vitro lung models while also investigating the effects two BPD-related factors: secondary infections, and oxygen transitions on an immature bronchial epithelium. We cultured primary human bronchial epithelial cells (hPBECs) in mono-, co- and tri-culture systems, the latter two incorporating pulmonary fibroblasts and/or endothelial cells, at air-liquid interface (ALI). VA was nebulized onto the apical side of the cultures using the Vitrocell® Cloud α system. The use of lipopolysaccharides (LPS) and oxygen transitions allowed us to mimic secondary infections and potentially oxidative stress, respectively. Based on gene expression and epithelial differentiation, our findings suggest that VA nebulization is effective in gene induction and promoting epithelial differentiation. Notably, while external VA is required for differentiation in mono-cultures, this is not essential in tri-cultures containing fibroblasts and endothelial cells. Additionally, our in vitro models demonstrated that LPS induces expression of genes related to inflammation and ECM remodeling, which was altered when culturing multiple cell types. Although further refinement is needed, these complex lung models provide a more physiologically relevant approach to study BPD beyond hyperoxia alone. In conclusion, this thesis emphasizes both the potential of VA nebulization as a therapeutic intervention and the need for advanced, co-cultured, in vitro models aimed at better capturing the complexity of BPD and improve treatment approaches for preterm infants.