Fig 1.
CS = cold storage, HOPE = hypothermic oxygenated perfusion, NORMO = normothermic blood-based perfusion, HCC = hepatocellular carcinoma, MRI = magnetic resonance imaging.
Table 1.
Graft cold storage-perfusion scheme.
Table 2.
Ex vivo perfusions parameters.
Fig 2.
Ex vivo perfused liver graft fluidodynamics and metabolism.
a. Left, hypothermic perfusion of DCD grafts shows modest flow increase over time, under controlled pressure conditions. Right, hypothermic perfusion of DCD grafts shows modest resistance to flow reduction over time. b. Left, normothermic perfusion of DCD grafts shows significant flow increase over time, under controlled pressure conditions. Right, normothermic perfusion of DCD grafts shows significant resistance to flow reduction over time. c. Direct comparison of resistance to flow changes between hypothermic and normothermic ex vivo perfusion. d. Left, visual comparison of inflow vs. outflow haemoglobin saturation during normothermic perfusion. Second from left, oxygen uptake of DCD grafts on normothermic perfusion. It shows increasing oxygen consumption that reaches a plateau after one hour from perfusion initiation. Third from left, non-cumulative bile production of DCD grafts on normothermic perfusion. It shows constant rate bile production after the first hour of perfusion. Right, transaminase in the perfusion solution. It shows enzyme accumulation during perfusion, symptom of graft ischemia/reperfusion injury. DCD = donation after circulatory death, HOPE = hypothermic oxygenated perfusion, NORMO = normothermic blood-based perfusion, AST = aspartate aminotransferase, ALT alanine aminotransferase.
Fig 3.
Ischemia/reperfusion injury in DCD ex vivo perfused liver grafts.
a. 1h DCD donor prior and cold flushing. Arrows indicating the wide cut in the diaphragm.b. Comparison of DCD grafts during hypothermic and normothermic perfusion and after reperfusion in the recipient. Normothermic treatment allowed for more homogeneous perfusion of the grafts and reduction of the local vasospasm. c. Histological comparison of liver grafts prior to implantation. All DCD livers presented similar amount of apoptotic hepatocytes (black arrows). DCD and DCD+HOPE grafts presented loss of intercellular cohesion. DCD+NORMO grafts showed loss of intercellular cohesion to a minor extent compared to DCD and DCD+NORMO grafts. DCD = donation after circulatory death, HOPE = hypothermic oxygenated perfusion, NORMO = normothermic blood-based perfusion.
Fig 4.
Pre- and post transplant ischemia/reperfusion injury assessment.
a. Pre implantation graft I/R-induced genes expression (fold increase). The mRNA levels of Serpine 1, F3 and Hmox were increased in the DCD grafts after normothermic perfusion, while there was no difference in the expression of these genes in all other groups (Fresh vs. NORMO p<0.005, DCD vs. NORMO p<0.005, HOPE vs. NORMO p<0.005). Irp94 and Hif1a expression was up-regulated both in the DCD+HOPE and DCD+NORMO, although the latter to a greater extent (DCD+HOPE vs. DCD+NORMO p<0.05). No difference was found in the expression of HMGB1 among all pre implantation grafts. b. 24h post transplant serum transaminase. DCD and DCD+HOPE recipients had very high levels of both AST (Fresh vs. DCD p = 0.012, Fresh vs. DCD+HOPE p = 0.016) and ALT (Fresh vs. DCD p = 0.006, Fresh vs. DCD+HOPE p = 0.008). DCD+NORMO recipients by contrast showed lower levels of both liver enzymes (DCD+HOPE vs. DCD+NORMO p = 0.016 for both AST and ALT). c. 24h post transplant serum HMGB1. Circulating HMGB1 was lower in the Fresh liver recipients, while no difference was found among the DCD recipients, whether ex-vivo perfused or not (Fresh vs. DCD, DCD+HOPE, DCD+NORMO p<0.05). HMGB1 = high mobility group box 1, Hif1a = hypoxia-inducible factor 1, rplp1 = ribosomal protein large P1, Serpine1 = plasminogen activator inhibitor type 1, Hmox1 = heme oxygenase 1, irp94 = ischemia-responsive protein 94, I/R = Ischemia/reperfusion, DCD = donation after circulatory death, HOPE = hypothermic oxygenated perfusion, NORMO = normothermic blood-based perfusion, AST = aspartate aminotransferase, ALT alanine aminotransferase.
Fig 5.
Post transplant survival and HCC development.
a. Post liver transplant survival. b. POD 28 HCC volumes. Tumour growth was homogeneous between the Fresh recipients. Non ex-vivo perfused DCD liver recipients developed larger tumours (Fresh vs. DCD p = 0.0006). DCD+HOPE and DCD+NORMO showed more variability in HCC size. DCD+HOPE tumours were overall larger than those of the Fresh recipients (Fresh vs. DCD+HOPE p = 0.014). DCD+NORMO were not significantly different from the Fresh group (Fresh vs. DCD+NORMO p = 0.62, DCD vs. DCD+NORMO p = 0.23) POD = postoperative day, HCC = hepatocellular carcinoma, DCD = donation after circulatory death, HOPE = hypothermic oxygenated perfusion, NORMO = normothermic blood-based perfusion.