Introduction: Limited evidence suggest airway epithelial structure and function is disrupted in preterm infants; however, morphology and physiology has not been examined in those most at risk of ongoing respiratory complications ? infants born very preterm (<32 weeks gestation). This study aimed to characterise the nasal airway epithelium from one year old survivors of very preterm birth.

Methods: We attempted to establish differentiated cultures from nasal brushings of infants born either at term or very preterm. RNA was then collected for PCR analysis of cell type characterisation markers and tight junction genes. Barrier integrity was assessed using transepithelial electrical resistance (TEER) and cell permeability assays. Data presented as mean ± SD.

Results: Pseudostratified cultures with visible cilia and goblet cell production were established in 55% of preterm and 90% of term samples (term n=9 [5 male], 2.7 ± 0.5 years, successful preterm n=12 [2 male], GA = 28.2 ± 2.4 wks, 1.4 ± 0.09 years; unsuccessful preterm n=10 [7 male], GA= 28.1 ± 2.7 wks, 1.4 ± 0.10 years].  Gene expression of cell type markers KRT5, MUC5A, TUBB and VIM were not significantly different between cohorts. Although TEER did not differ, preterm cultures were significantly more permeable (4.3 ± 3.5 x10^-4 cm/sec vs 9.8 ± 4.1 x10^-4 cm/sec, p<0.01). Tight-junction gene expression of TJP1, CLDN1 and OCEL1 also did not differ.

Conclusions: Results show that the airway epithelium differs in survivors of very preterm birth.  A compromised barrier function may facilitate infection and injury, which can negatively impact overall lung health.