Upregulated Expression of Circulating MicroRNAs in Kidney Transplant Recipients With Interstitial Fibrosis and Tubular Atrophy

Introduction. The discovery of circulating microRNAs (miRNAs), as potential noninvasive diagnostic biomarkers, has opened new avenues of research for identifying transplant patients with chronic allograft dysfunction. The present study aimed to investigate the expression levels of 4 immune-related miRNAs, miR-21, miR-31, miR-142-3p, and miR-155, in plasma samples of kidney allograft recipients. Materials and Methods. The plasma expression levels of the miRNAs were evaluated by quantitative real-time polymerase chain reaction in 53 kidney recipients with long-term stable allograft function (n = 27), biopsy-proven interstitial fibrosis and tubular atrophy (n = 26), and healthy controls (n = 15). The possible correlation between clinical parameters and the circulating miRNAs and the receiver-operating characteristic analysis were performed. Results. Significantly upregulated expressions of miR-21 (P = .02), miR-142-3p (P = .048), and miR-155 (P = .005) were observed in plasma samples of recipients with interstitial fibrosis and tubular atrophy in comparison to the stable allograft function and healthy control groups. Expression level of the miR-21 in plasma was correlated with creatinine (r = -0.432, P = .03) and estimated glomerular filtration rate (r = 0.423, P = .031). Multivariable analysis indicated that miR-21, miR-142-3p, and miR-155 in plasma samples could discriminate almost most of the patients with interstitial fibrosis and tubular atrophy (area under curve, 0.802; sensitivity, 81%; specificity, 92%). Conclusions. Our data suggested that altered expression of miR-21, miR-142-3p, and miR-155 in plasma samples might be associated with kidney allograft dysfunction and could be used for graft monitoring in kidney transplantation.