Diagnostic potential of serum miR-197 and IL-18 levels in predicting bronchopulmonary dysplasia: a prospective cohort study

Bronchopulmonary dysplasia (BPD) remains a major complication of prematurity, contributing significantly to infant mortality and long-term morbidity. Current diagnostic methods for BPD rely on clinical criteria assessed at 36 weeks postmenstrual age, underscoring the urgent need for earlier predictive biomarkers to enable timely intervention. MicroRNAs (miRNAs) and inflammatory cytokines, such as interleukin-18 (IL-18), have emerged as promising circulating biomarkers for various diseases. Specifically, miR-197 has been implicated in the regulation of inflammatory pathways and lung disease, whereas IL-18 functions as a key pro-inflammatory cytokine. However, their combined role in the early prediction of BPD remains unexplored. This study aimed to investigate the dynamic changes in serum miR-197 and IL-18 levels, as well as their diagnostic potential as early biomarkers of BPD in preterm infants. A total of 129 premature newborns admitted to the Neonatal Intensive Care Unit at the First People’s Hospital of Yinchuan from January 2022 to December 2023 were enrolled in this prospective cohort analysis. The participants were stratified based on BPD status, in accordance with the National Institute of Child Health and Human Development (NICHD) guidelines, yielding 32 cases of BPD and 97 non-BPD controls. The serum IL-18 levels were measured through enzyme-linked immunosorbent assay (ELISA), while quantitative real-time polymerase chain reaction (qRT-PCR) was implemented for determining miR-197 expression at three critical time intervals: postnatal days 1, 7, and 14. The potential relationships between these biomarkers over the study period were determined via bivariate correlation analyses. The diagnostic potential of miR-197 and IL-18, both individually and in combination, was assessed through receiver operating characteristic (ROC) curve analyses. The BPD group required significantly longer durations of mechanical ventilation and Continuous Positive Airway Pressure (CPAP) assistance, and had a lower gestational age relative to the non-BPD group, and the variations were statistically significant. The serum miR-197 levels decreased significantly in the BPD group compared to those in the non-BPD group on postnatal days 1, 7, and 14, whereas IL-18 levels increased significantly (P < 0.05). However, serum IL-18 levels gradually increased the BPD cohort over time (P < 0.05). The serum levels of miR-197 and IL-18 levels exhibited an inverse correlation in the infants with BPD on postnatal days 1, 7, and 14 (r = -0.697, -0.816, and -0.746, respectively; P < 0.01). ROC curve analysis demonstrated that the combined detection of serum miR-197 and IL-18 levels on postnatal day 7 proved highly effective in estimating the risk of BPD. Serum levels of miR-197 and IL-18 are likely associated with the onset and progression of BPD. The combined measurement of the serum levels of miR-197 and IL-18 may represent a promising biomarker strategy for the early detection of BPD and the assessment of disease severity.