Circulating RNA Profiling in Postreperfusion Plasma From Kidney Transplant Recipients

Background: Ischemia/reperfusion injury (IRI) is inevitable in kidney transplantation (KT) and may lead to impaired tubular epithelial cell function and reduce graft function and survival. Renal IRI is a complex cellular and molecular event; therefore, investigating the genetic or molecular pathways associated with the early phase of KT would improve our understanding of IRI in KT. MicroRNAs (miRNAs) play a critical role in various pathologic events associated with IRI. Methods: We compared the expression profile of miRNAs extracted from 2 blood plasma samples, 1 from periphery and the other form gonadal veins immediately after reperfusion, in a total 5 cases of KT. Results: We observed that the total RNA yield was higher in postreperfusion plasma and that a subset of miRNAs was upregulated (miR-let-7a-3p, miR-143-3p, and miR-214-3p) or downregulated (let-7d-3p, let-7d-3p, miR-1246, miR-1260b, miR-1290, and miR-130b-3p) in postreperfusion plasma. Gene ontology analyses revealed that these subsets target different biological functions. Twenty-four predicted genes were commonly targeted by the upregulated miRNAs, and gene ontology enrichment and pathway analyses revealed that these were associated with various cellular activities such as signal transduction or with components such as exosomes and membranous organelles. Conclusion: We present 2 subsets of miRNAs that were differentially upregulated or downregulated in postreperfusion plasma. Our findings may enhance our understanding of miRNA-mediated early molecular events related to IRI in KT.