Urinary NGAL,IGFBP-7 And TIMP-2 As Early Biomarkers Of Contrast Medium-induced Acute Kidney Injury In Children

Objective:To investigate the value of combined detection of urinary neutrophil gelatinase-associated lipocalin(NGAL),insulin like growth factor binding protein-7(IGFBP-7),tissue inhibitor of metalloproteinase-2(TIMP-2)in early diagnosis of children with contrast medium–induced acute kidney injury(CI-AKI).Methods:137 cases of children who intravascular injection of iodine contrast agent(group of contrast medium),35 cases health children as control group.According to the time point of intravascular injection of contrast agent(Angiography before(0h),2h,6h,12 h,24h,48 h after angiography),group of Contrast medium is divided into six groups.The serum creatinine level was detected by automatic biochemical analyzer in contrast group and control group.The dynamic changes of NGAL,IGFBP-7 and TIMP-2 levels in urine of children in control group and group of contrast medium were detected by enzyme-linked immunosorbent assay.Results:CI-AKI occured in 20 of 137 enrolled patients,the incidence was 14.59%.There was no significant difference of NGAL and IGFBP-7 levels in urine in control group and group of contrast medium before intravenous contrast agent in non CI-AKI group(P>0.05).The level of TIMP-2 and [IGFBP-7]*[TIMP-2] in urine were increased and reached the peak at 2h after angiography,but the level was significantly lower than CI-AKI group.In CI-AKI group,NGAL levels in urine reached a peak at 2h,then gradually decreased to the pre-contrast level at 24 h.IGFBP-7 levels in urine increased significantly at 2h and reached the peak at 6h,and then decreased gradually at 24 h after angiography,which was close to the level before angiography.The level of TIMP-2 in urine was significantly higher at 2h after angiography than reached the peak at 6h,before angiography,then gradually decreased to the pre-contrast level at 12 h.The level of [IGFBP-7]*[TIMP-2] levels in urine increased significantly at 2h and reached the peak at 6h,and then gradually decreased to the pre-contrast level at 24 h.The area under the ROC curve diagnosis CI-AKI of NGAL in the urine after 2 hours of surgery was 0.718[95% CI:0.575-0.860].The area under the ROC curve diagnosis CI-AKI of TIMP-2 and IGFBP-7 in the blood after 6 hours of surgery was 0.779(95% CI:0.658-0.901)and 0.779(95% CI:0.650-0.908).The area under the ROC curve diagnosis CI-AKI of [IGFBP-7]*[TIMP-2] in the urine after 6 hours of surgery was 0.811(95% CI:0.681-0.941).Conclusion:NGAL,TIMP-2 and IGFBP-7 concentration in the urine of patients after intravenous contrast agent was earlier rise than that of SCr,and had the value of early diagnosis of CI-AKI,NGAL,IGFBP-7 and TIMP-2 in urine had a good clinical value for early diagnosis of CI-AKI in children.Children of non CI-AKI group may be mild,short of kidney damage after injection of contrast agent.The combination of TIMP-2 and IGFBP-7 was better than either analyte alone.