Sanguineous normothermic machine perfusion improves hemodynamics and biliary epithelial regeneration in donation after cardiac death porcine livers

Abstract

The effect of normothermic machine perfusion (NMP) on post-reperfusion hemodynamics and extrahepatic biliary duct histology of donors after cardiac death (DCD) livers after transplantation has not been addressed thoroughly and represented the object of this study. Ten livers (n=5/group) with 60’ of warm ischemia were preserved by cold storage (CS) or sanguineous NMP for 10 hours, and then reperfused for 24 hours with whole blood in an isolated perfusion system to simulate transplantation. In our experiment, arterial and portal venous flows were stable in NMP group during the entire simulated reperfusion, while decreased dramatically in CS group after 16 hours post-reperfusion (P<.05), findings consistent with severe parenchymal injury. Similarly, significant differences existed between CS and NMP group on hepatocellular enzyme release, bile volume produced, and enzyme released into bile (P<.05). On histology CS livers presented with diffuse hepatocyte congestion, necrosis, intraparenchymal hemorrhage, denudated biliary epithelium and submucosal bile duct necrosis, while NMP liver showed very mild injury in liver parenchyma and biliary architecture. Most importantly, Ki67 staining in extrahepatic bile duct showed biliary epithelial regeneration. Our findings advance the knowledge of post-reperfusion events that characterize DCD livers and propose NMP as a beneficial preservation modality able to improve biliary regeneration after a major ischemic event, which may prevent in clinical transplantation the development of ischemic cholangiopathy.

Liver Transplantation After Ex Vivo Normothermic Machine Preservation: A Phase 1 (First-in-Man) Clinical Trial

“…Experimental data from large animal studies, specifically investigating biliary epithelial recovery following a period of warm ischemic and NMP, suggest that warm oxygen delivery may provide a critical advantage (29,30). This is a key issue in the quest to increase the utilization of DCD organs in liver transplantation and will only be addressed in the context of a randomized trial with longer-term follow-up of patients.…”

Comparing Normothermic Machine Perfusion Preservation With Different Perfusates on Porcine Livers From Donors After Circulatory Death

“…They were treated respectively, as presented previously (22,23). The blood collected from donors was used directly as NMP perfusate or washed to separate RBCs.…”

“…Arterial and venous resistance in hemodynamics was calculated (pressure divided by flow per 100 g liver tissue). Liver biopsies stained with hematoxylin and eosin (H&E) were evaluated on light microscopy using a semiquantitative injury scoring system, as described previously (23), by a pathologist (A.B.) blinded to group assignments.…”

“…In addition to liver biopsies, a biopsy was taken at the bifurcation of the extrahepatic bile duct to the left and right hepatic lobe after 24 h of reperfusion and stained with H&E. Injury was evaluated using a semiquantitative scoring system by light microscopy, as described previously (23). Biliary epithelium regeneration within the bile duct and peribiliary glands (PBGs) was investigated using immunohistochemical staining (rabbit antibody; Novocastra, Richmond, VA) for the Ki67 protein, a cellular marker strictly associated with cell proliferation (30).…”

Protective Mechanisms of Hypothermia in Liver Surgery and Transplantation

“…In a pig model of liver preservation, 10 h of NMP proved superior to SCS, as determined by liver injury parameters (AST release, bile production) as well as liver histology after 24 h of reperfusion (89). In a similar experimental model, SCS elicited severe biliary necrosis, compared with only mild biliary damage after NMP (90). In addition, cholangiocyte proliferation was observed after NMP, indicating that NMP might be able to reduce biliary complications after transplantation by securing adequate cholangiocyte oxygenation during preservation.…”