MicroRNA-21 Downregulates Inflammatory Mediators To Protect The Kidney In Children Undergoing Congenital Cardiac Surgery With Cardiopulmonary Bypass

ObjectiveTo investigate the relationship of miroRNA-21 (miR-21), tumor necrosis factor-a(TNF-a) and acute kidney injury(AKI) in children undergoing congenital cardiac surgery with cardiopulmonary bypass(CPB)> verify miR-21 downregulates inflammatory mediators to protect the kidney.MethodsChildren who were hospitalized between December 2013 and January 2015 in department of cardiothoracic surgery of Hunan children’s hospital, diagnosed as congenital heart disease, scheduled for cardiac surgery with CPB were eligible for enrollment. They were randomly divided into control group and intervention group, and the intervention group were performed remote ischemic preconditioning 12 hours before CPB. Then observe the incidence and clinical risk factors of acute kidney injury (AKI) in children Detect the serum creatinine level、TNF-α and miR-21 expression in blood and urine before and after CPB. Enzyme-Linked Immunosorbnent Assay (ELISA) detect the TNF-a expression and real-time quantitative PCR detect the miR-21 expression in blood and urine.ResultsA total of 449 children were enrolled in the study, male vs female was 1.18, and their median age was (37.50±25.31)months. The control group has 249 patients and other 200 patients are in intervention group. There were no significant differences in age and sex composition between the two group(P >0.05).The Serum creatinine level in the intervention group was significantly lower than that in the control group at 24h and 48h after CPB (P<0.01); The incidence of AKI in intervention group was also significantly lower than that in the control group (19.0% vs.46.2%,P<0.01)There were no significant differences in the operation time, parallel cycle time, blood flowing time, number of introperative hypotension duration of mechanical ventilation and intensive care unit between the AKI patients and non-AKI patients of control group (P>0.05), but the difference in the arotic clamping time and the classification of the complexity of the operation were significant (P<0.01)The serum TNF-a expression in the intervention group was significantly lower than that in the control group at 6h、24、48h after CPB (P<0.01); and the urine TNF-a expression in the intervention group was significantly lower than that in the control group at 24h、48h and 72h after CPB (P<0.01)The plasma miR-21 expression in the intervention group increased significantly from Oh to 72h after CPB and 17.3 times of the baseline level at 24h.The urine miR-21 expression in the intervention group also increased significantly, which was 5.32 times of the baseline level at 6h after CPB, 13.75 times at 24h,10.04 times at 72h and then declined to the baseline level at 5d.The miR-21 expression in plasma and urine of the control group didn’t change obviously.ConclusionThe remote ischemic preconditioning has protective effect on the kidney in children with congenital heart disease, which can reduce the incidence of AKI after CPB.The protection of remote ischemic preconditioning to kidney in children Undergoing congenital cardiac surgery with CBP is closely related to the inhibition of inflammatory mediators.The remote ischemic preconditioning upregulates miR-21 expression to protect the kidney in children Undergoing congenital cardiac surgery with CBP, and the protection may be related to inhibiting the expression of inflammatory mediators.