Plasma microRNA, a potential biomarker for acute rejection after liver transplantation

Acute rejection (AR) of an organ transplant is a life-threatening complication. Currently, there are few diagnostic biomarkers suitable for clinical application. We aim to determine the potential of plasma microRNAs as biomarkers for AR. Using rat orthotopic liver transplantation model and microarrays, we compared the difference in the spectrum and levels of microRNAs in both plasma and grafts between AR rats and control. AR-related plasma microRNAs were selected and validated using real-time quantification polymerase chain reaction. Plasma from AR rats with or without tacrolimus treatment was used for microRNA dynamic monitoring. To clarify the origin of AR-related plasma microRNAs, drug-induced liver damage rat model were performed and in situ hybridization was used to detect and localize the specific microRNA in allografts. We found that plasma miR-122, miR-192, and miR-146a was significantly up-regulated when AR occur (fold change>2; P