Bootcongres

The peribiliary glands of large bile ducts have been identified as a niche of progenitor cells that contribute to regeneration of biliary epithelium after injury. It is unknown whether injury to the peribiliary glands is a risk factor for the development of non-anastomotic biliary strictures (NAS) after liver transplantation. Moreover, it is unknown whether pretransplant biliary injury is different in livers donated after brain death (DBD) or cardiac death (DCD). In 128 liver transplant procedures, biopsies were taken from the distal common bile duct and injury was assessed using a systematic histological grading system. Histological injury in relation to posttransplant biliary strictures was studied and compared between DBD (n=97) and DCD livers (n=29). Luminal biliary epithelial loss >50% was observed in 91.8% of the grafts before transplantation, yet NAS occurred in only 16.4%. Periluminal peribiliary glands were more severely injured than the deep peribiliary glands located near the fibromuscular layer (>50% loss in 56.9% versus 17.5%, respectively; p<0.001). Injury of deep peribiliary glands was more prevalent and more severe in livers that later developed NAS, compared to grafts without NAS (>50% loss in 50.0% versus 9.8%, respectively; p=0.004). In parallel, injury of the peribiliary vascular plexus was more severe in livers that developed NAS, compared to grafts without NAS (>50% vascular changes in 57.1% versus 20.3%; p=0.006). Comparison of DBD and DCD livers revealed significantly more vascular injury in the latter (p=0.005). Conclusion: Injury of peribiliary glands and vascular plexus before transplantation is strongly associated with the occurrence of biliary strictures after transplantation. This suggests that insufficient regeneration due to loss of peribiliary glands or impaired blood supply may explain the development of biliary strictures.