Poster 30. Elevated plasma levels of cell-free DNA during orthotopic liver transplantation are associated with activation of coagulation

Thursday 14 march 2019

13:12 - 13:15h

Categories: Klinisch, Postersessie

Parallel session: Postersessies 6 - Clinical

F.A. von Meijenfeldt1, L.C. Burlage2, S. Bos3, J. Adelmeijer4, R.J. Porte1, J.A. Lisman1

1Dept. of Surgery, HPB & Livertransplantation, 2Dept. of Surgery, 3Dept. of Internal Medicine, 4Surgical Researchlab,University Medical Center Groningen, Groningen,The Netherlands.

Background: Patients undergoing liver transplantation have complex changes in their hemostatic system, and the net effect of these changes appears a ‘rebalanced’ hemostatic profile. Recently, neutrophil extracellular traps (NETs) were discovered. Upon activation, neutrophils expel DNA, histones and granular proteins such as neutrophil elastase extracellularly, that together form web-like structures called NETs. NETs were first described in the context of pathogen entrapment and killing. Increasing evidence suggests a crucial role for NETs, and their main component cell-free DNA in activation of coagulation. As liver transplantation is associated with substantial (hepatocyte) cell death and intrahepatic neutrophil accumulation, NETs might play an important role in the hemostatic balance during liver transplantation. The aim of this study was to determine whether formation of NETs occurs during liver transplantation and examine their association with activation of coagulation.

Methods: Twenty-one patients undergoing a liver transplantation were included in this study. Plasma samples were obtained at four time points during transplantation and up to 6 days after transplantation. Patient plasma levels of cell-free DNA, nucleosomes and myeloperoxidase (MPO)-DNA complexes (markers for NETs) were determined using enzyme-linked immunosorbent assays and compared with plasma levels in healthy controls. Moreover, markers for activation of coagulation were assessed in the plasma samples. Post-reperfusion liver biopsies were stained for neutrophil elastase.

Results: Perioperative increases of plasma levels of markers for NETs were found with levels of cell-free DNA and nucleosomes that peaked after reperfusion, and MPO-DNA complexes that peaked during the anhepatic phase. Cell-free DNA and nucleosome levels, but not MPO-DNA levels (which is the most specific marker of NETs), were associated with markers for activation of coagulation. Immunostainings of post-reperfusion liver biopsies were suggestive for intrahepatic NET formation.

Conclusions: This study indicates that NET formation occurs during liver transplantation. However, the majority of circulating DNA appears to be derived from cell death within the graft and not from formation of NETs. Elevated plasma levels of cell-free DNA and nucleosomes, and not MPO-DNA, were associated with activation of coagulation and might contribute to the complex hemostatic rebalance during liver transplantation.