Precision-cut bile duct slices as a model to study regeneration of bile ducts of human donor livers after ischemic preservation injury

Introduction Clinical studies have shown a high incidence of biliary epithelial injury after cold ischemic preservation of donor livers. Insufficient epithelial regeneration from the peribiliary glands (PBGs) has been proposed as a critical mechanism in the pathogenesis of biliary strictures after transplantation. Severe biliary epithelial injury requires proliferation and mobilization of biliary progenitor cells nested in PBGs. Studies on the pathogenesis and prevention of biliary strictures are hampered by the lack of suitable laboratory and animal models. Precision-cut tissue slices are a widely used ex vivo technique, in which thin slices of human tissue are cultured and kept viable with intact intercellular and cell-matrix interactions for up to several days. Aims The aim of this study was to generate precision-cut bile duct slices and study their suitability as a model to study the regenerative capacity of PBGs in donor bile ducts. Methods Large bile ducts of cold preserved livers declined for transplantation (n=10) were isolated and sliced, using a Krumdieck slicer. Bile duct slices were cultured in Williams’ medium E up to 144 hr. Histology and immunohistochemistry (HE, Ki-67, and K19) were performed to assess cell morphology. Results Viable K19-positive PBG cells were observed at all time points. Cell proliferation rate, as assessed by Ki-67 staining, increased from 0% at 24 hr to 25% at 96 hr of culture. Proliferation rate was significantly higher in bile ducts of donors <60 years, compared to donors ≥60 years (21% vs. 11%, p = 0.026) Conclusions Precision-cut bile duct slices are a feasible model to study biliary epithelial regeneration of ischemic injured donor liver bile ducts. This model provides a new ex vivo tool to develop pharmacological strategies to prevent post-transplant biliary strictures.