Abstract
INTRODUCTION: Bronchopulmonary dysplasia (BPD) remains the most significant complication of extreme prematurity, affecting long-term respiratory outcomes. Because current diagnostic criteria identify only established lesions at 36 weeks postmenstrual age, early non-invasive biomarkers are needed. This pilot study aimed to identify a candidate salivary miRNA panel associated with BPD risk and to explore its pathogenetic relevance through in silico analysis. METHODS: Saliva was collected from 20 preterm infants (10 with BPD and 10 controls), and miRNA expression was profiled using the GeneChip™ miRNA 4.1 Array Plate. Discriminatory performance was explored by ROC analysis within this discovery cohort, together with power and Spearman correlation analyses. RESULTS: FC ≥ 1.0), with no significant correlation with gestational age or birth weight. Bootstrap-corrected AUC values ranged from 0.905 to 0.937 and were supported by leave-one-out cross-validation. All three miRNAs showed very large effect sizes exceeding the minimum detectable effect at 80% power. CONCLUSIONS: In this pilot study, salivary miRNAs represent a hypothesis-generating candidate biomarker signal for BPD that requires external validation in larger, independent cohorts before any diagnostic or prognostic application can be considered.