Circulating MicroRNA-188, -30a, and -30e as Early Biomarkers for Contrast-Induced Acute Kidney Injury

Abstract

Background: Contrast-induced acute kidney injury (CI-AKI) is typically defined by an increase in serum creatinine after intravascular administration of contrast medium. Because creatinine is an unreliable indicator of acute changes in kidney function, we assessed whether circulating microRNAs (miRNAs) could serve as biomarkers for early detection of CI-AKI.

Methods and results: Using a rat model of CI-AKI, we first evaluated the miRNA profile of rat plasma and kidney. Three miRNA species with >1.5-fold increase in plasma samples of CI-AKI rats, including miRNA-188, miRNA-30a, and miRNA-30e, were selected as candidate miRNAs. Quantitative real-time polymerase chain reaction showed that these candidate miRNAs peaked in concentration around 4 hours after contrast medium exposure and were relatively renal-specific. We compared the plasma levels of these candidate miRNAs in 71 patients who underwent coronary angiography or percutaneous coronary intervention and developed CI-AKI with those of 71 matched controls. The plasma levels of the 3 candidate miRNAs were significantly elevated in the CI-AKI group as compared to the control group. Receiver operating characteristic analysis showed that these miRNAs significantly distinguished patients with CI-AKI from those without CI-AKI. MiRNA composites were highly accurate for CI-AKI prediction, as shown in maximized specificity by treble-positive miRNA composite or maximized Youden index by any-positive miRNA composite. Moreover, the selected miRNAs changes were associated with Mehran Risk Scores.

Conclusions: Plasma levels of candidate miRNAs significantly distinguished patients with CI-AKI from those without CI-AKI. Thus, miRNAs are potential biomarkers for early detection of CI-AKI.

Keywords: biomarker; contrast‐induced nephropathy; microRNA.

© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Figures

Figure 1

Selection of candidate circulating miRNAs as early biomarkers for CI‐AKI in rats. A, Global miRNA expression profiles of kidney and plasma in CI‐AKI and control rats by miRNA microarrays. Principal component analysis (PCA) revealed that the hybridization results of 2 plasma samples (1 from the CI‐AKI group and 1 from the control group) were significantly different from the other plasma samples. These 2 components explained 81.19% of the variability. B, Hierarchical clustering analysis of dysregulated miRNAs (with a fold change >1.5) in plasma and kidney samples. The relative miRNA expression is depicted according to the color scale shown on the right. Red indicates upregulation and blue, downregulation. C, Diagram of the strategy for identifying candidate miRNAs. See Results for details. CI‐AKI indicates contrast‐induced acute kidney injury; CM, contrast medium; miRNA, microRNA; NS, normal saline; PCA, principal component analysis.

Figure 2

Validation of candidate circulating miRNAs in rats. A, Tissue expression patterns of miRNAs in rats. The levels of candidate miRNAs in various tissues from rats by reverse transcription quantitative real‐time PCR (RT‐qPCR). B, Validating data of miRNA microarray by RT‐qPCR method. C, Time course of the plasma levels of candidate miRNAs from CI‐AKI rats. The plasma was collected from the rats at different time points (n=4 for each time point). Levels of miRNAs at each time point were expressed as fold increase relative to the baseline. D, The plasma was collected from control rats (without pretreatment and CM exposure), CM‐only group (CM exposure without pretreatment), dehydration‐only group (dehydration pretreatment without CM exposure), and CI‐AKI group at 4 hours after CM exposure or equal time point (n=4, each group). The relative change of miRNA levels is expressed as fold increase compared with the control.*P<0.05, **P<0.01, and ***P<0.001. CI‐AKI indicates contrast‐induced acute kidney injury; CM, contrast medium; miRNA, microRNA; RT‐qPCR, reverse transcription quantitative real‐time polymerase chain reaction.

Figure 3

Evaluation of candidate circulating miRNAs in CI‐AKI patients. A, The plasma levels of the three candidate miRNAs in 71 CI‐AKI patients and 71 matched controls without CI‐AKI by RT‐qPCR. Blood samples were obtained at baseline and 4 to 6 hours post CM exposure. Individual value plots represent the relative change of miRNA levels compared with baseline in each CI‐AKI patient (left) and non‐CI‐AKI patient (right). A crossbar on each plot indicates the mean expression level for each group. ***P<0.001. B, Discrimination potential of candidate circulating miRNAs. Receiver operating characteristics (ROC) curves were drawn with the data of fold change of plasma microRNAs from 71 CI‐AKI patients and 71 matched controls. The dashed line indicates “random guess” diagonal line. AUC indicates area under the curve; CI‐AKI, contrast‐induced acute kidney injury; CM, contrast medium; miRNA, microRNA; RT‐qPCR, reverse transcription quantitative real‐time polymerase chain reaction.

Figure 4

Candidate circulating miRNAs were associated with Mehran Risk Scores. A, Comparison of mean Mehran Risk Scores and incidence of Mehran Risk Score ≥6 between CI‐AKI and non‐CI‐AKI patients by different CI‐AKI criteria. B, Mean Mehran Risk Score and incidence of Mehran Risk Score ≥6 in 4 categories of patients. +/+ indicates patients who met the CI‐AKI criteria based both on miRNA and CyC/SCr; +/− indicates patients who met the CI‐AKI criteria based on miRNA but not CyC/SCr; −/+ indicates patients who met the CI‐AKI criteria based on CyC/SCr but not miRNA; −/− indicates patients who did not meet the CI‐AKI criteria based both on miRNA and CyC/SCr. Any‐positive, the fold‐change of any 1 of the 3 selected miRNAs reaching cutoff point I; treble‐positive, the fold‐change of all 3 selected miRNAs reaching cutoff point I. Error is represented as SEM. **P<0.01. ***P<0.001. CI‐AKI indicates contrast‐induced acute kidney injury; CyC/SCr, cystatin C/serum creatinine; miRNA, microRNA.