Background: Ischemia reperfusion injury (IRI) is a multifactorial process that impact liver graft function. Donor quality plays a critical role during IRI and early graft outcomes. Extracellular vesicles (EVs) provide a novel source of valuable biomarkers. We propose that EV-miRNAs are leaking from the liver donor into the perfusate and that these markers reflect organ quality and relate to allograft function-post-transplant.

Samples and Methods: We evaluated perfusate (10 cc) from 31 liver grafts obtained at pre implantation at the end of cold ischemia time (CIT) Our studies include determination of EV size(Tunable Resistive Pulse Sensing (TRPS) and Cryo- Electron Microscopy (CEM)), quantification (using TRPS and Imaging Flow Cytometry (IFC)) and phenotyping (using IFC).Deceased donor (DD) livers included standard, extended criteria donor as well as partial (living donor (LD)) grafts. EV-miRNAs were evaluated using miScript miRNA PCR Array Human Liver miFinder 384H. For identification of differentially expressed EV-miRNAs the [Delta][Delta]C_t method was used. CIT, donor age, and transaminase levels at day 1 and 2 post-transplant were included as part of the analyses.

Results: Using a volume of 200 cc of perfusate, we were able to quantify ~ 1.5E+08 EVs. The effect of CIT on perfusate EV-miRNA profiles from DD (CIT > 4 hours) and LD organs (CIT < 1 hour) showed increase of miR-5701 and a decrease of miR-122-5p, miR-260a. miR-19a- 3p, miR-3183, miR-4301, and miR-92a-3p. Older donors livers (> 65 years old) showed a significant up regulation of miR 122-3p, miR-122-5p, miR-1260 and miR-192-5p in their perfusates compared to young donor livers. Furthermore, a significant increase of AST/ALT on recipient at 24 hrs post-transplantation relates to increased expression of miR-101-3p, miR-106b-5p, miiR-142-3p, miR-199b-3p, miR-22-3p, miR-29a-3p, miR-29b-3p, and miR-29c-3p.

Conclusions: Perfusate EV-miRs are excellent candidates as markers of donor quality and tissue injury, they provide information about parent affected liver cells and the profiles relates to early graft outcomes. Further evaluation of cellular origin affected pathways may lead to discovery of target for therapeutic interventions.

CITATION INFORMATION: Fernandez A., Ingram O., Bontha S., Erdbruegger U., Musante L., Mas V., Maluf D. Extracellular Microvesicles from Liver Perfusate: microRNAs, Cellular Cross-Talk, and Early-Post Liver Transplant Outcomes Am J Transplant. 2017;17 (suppl 3).

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