MicroRNA profiles in preterm children with regard to BPD and echocardiographic findings.

BACKGROUND: The associations between microRNA profiles in peripheral blood leukocytes and previous occurrence of bronchopulmonary dysplasia (BPD) and current echocardiographic findings were studied in preschool and school-age preterm children with a birth weight < 1,500 grams and/or gestational age at birth < 32 weeks. METHODS: The prospective study was conducted in 152 children with a median age of 5.42 years diagnosed (n = 46) or not diagnosed (n = 106) with BPD and 92 age-matched normal term children (controls). RESULTS: A higher incidence of abnormal echocardiographic findings was detected in preterm children regardless of BPD occurrence compared to normal term controls. Preterm children shared altered microRNA profiles regardless of BPD occurrence (20 microRNAs in total; 17 upregulated, 3 downregulated). Additional 3 microRNAs were dysregulated in children without BPD and 1 microRNA in children with BPD. MiR-199a-5p differentiated between children with and without BPD. No significant differences in microRNA expression profiles were observed either among normal term controls or within the cohort of preterm children when stratified according to echocardiographic findings. CONCLUSION: Preterm children of preschool and school age show a higher incidence of abnormal echocardiographic findings compared to term-born controls. Although no association was identified between these findings and microRNA expression profiles, the impact of prematurity on microRNA expression appears to be well-defined. These results may contribute to the growing body of evidence emphasizing the importance of long-term follow-up in individuals born preterm, while further research is warranted to determine whether the observed microRNA alterations are predictive of later health complications.