Clinical Significance of miR-4535 and miR-191-5p in Maternal Serum as Independent Biomarkers for Severe Chorioamnionitis

Introduction: Chorioamnionitis, a perinatal condition caused by fetal membrane inflammation, results in preterm birth, neonatal sepsis, necrotizing enterocolitis, and brain disease in infants. However, predicting maternal and fetal prognoses is challenging. We aimed to assess the relationship between fetal infection induced by severe chorioamnionitis or morbidity and the expression levels of serum miR-4535, miR-1915-5p, and miR-191-5p levels, which are promising biomarkers for chorioamnionitis, in pregnant women with chorioamnionitis.

Methods: We collectedserum and amniotic fluid samples from 40 pregnant women with preterm labor and analyzed miR-4535, miR-1915-5p, and miR-191-5p expressions. We calculated the area under the curve (AUC) and Youden index to examine the diagnostic accuracy of infection-induced fetal morbidity.

Results: The serum miR-4535 and miR-191-5p levels were significantly higher in patients with severe chorioamnionitis than in those with chorionitis or sub-chorionitis (P = 0.001 and 0.003, respectively). The AUC of miR-4535 and miR-191-5p (0.864 and 0.836, respectively) indicated their good diagnostic accuracy for severe chorioamnionitis. Significant correlations were observed between serum and amniotic fluid miR-4535 expression (P = 0.011) and serum miR-4535 and miR-191-5p expressions. miR-4535 AUC accurately predicted elevated neonatal immunoglobulin M level (AUC = 0.922) and infection-induced fetal morbidity (AUC = 0.805).

Conclusion: Serum miR-4535 and miR-191-5p are associated with infection-induced severe chorioamnionitis and fetal morbidity and maternal infection, respectively.