High Circulating MiR-26a Expression Correlates To Respiratory Distress Syndrome In Premature Infant

[Background]Respiratory distress syndrome(RDS)is the main cause of respiratory insufficiency,as well as mortality and morbidity in preterm infants.The incidence of RDS increases with decreasing gestational age.Sixty per cent of infants born at<28 week gestation will develop RDS,with incidence of 30%in infants born between 28 and 34 week gestation,and in less than 5%of infants born after 34 week.Treatment of this disease has remained difficult and although the assistance of PS and mechanical ventilation has resulted in a marked reduction in mortality rates,the incidence of RDS does not follow a downward trend due to increased survival rates of low birth weight premature infants.miRNAs is a group of small non-coding RNAs,regulating gene expression by binding to specific target sites on messenger RNA to either repress or degrade targets.Many studies have highlighted roles of miRNAs in the regulation of fetal lung maturation and PS metabolism.Although there have been no previous reports regarding plasma miRNAs in RDS,those of other diseases can be of assistance.Therefore,theoretically,plasma miRNAs may be a suitable potential biomarker in the diagnosis of clinical diseases.In our previous studies,miR-26a was one of seven miRNAs that showed significant changes in expression at three time points in the developing rat lung.And PS synthesis is regulated by miR-26a in fetal rat AECIIs.These reports have indicated potential roles of miR-26a in lung development and PS synthesis and metabolism.[Objectives]To investigate the level of a subset of miR-26a in serum samples of the RDS and non-RDS subjects.In addition,we studied the correlation of the miR-26a with clinical parameters in the RDS subjects.[Methods]A total of 42 infants with RDS and 44 infants without RDS at a GA of 28-36 weeks were recruited between January and July 2016 from the Neonatal Intensive Care Unit of Nanjing Children's Hospital.The personal data and clinical measurements were collected,such as gestational age,gender,birth weight,delivery mode and so on.Serum miR-26a level was measured using real-time PCR.[Results]Our results showed that circulating miR-26a level exhibited higher compared to non-RDS controls[miRNA-26a(2-??Ct):13.382±7.208 vs 4.803±3.098,t=7.112,P<0.01].The level of plasma miR-26a expression was correlated with gestational age,birthweight,mode of birth and pregnancy-induced hypertension(t/F=4.504,2.772,-2.984,0.711,P<0.05).Logistic regression analysis showed that elevated plasma miR-26a,mode of birth were independent risk factors for RDS infants[OR(95%CI)=1.508(1.222-1.863),OR(95%CI)=0.080(0.012-0.553)]?[Conclusions]Plasma miR-26a may be a dangerous biomarker for premature infants with RDS.An increased level of miR-26a might associate with gestational age,birthweight,mode of birth,and pregnancy-induced hypertension.