Assessment of biliary regeneration during long term (>5 days) ex-vivo normothermic machine perfusion
Mark Ly1,2,3,5, Ngee-Soon Lau1,2,3, Claude Dennis4, Joanna L Huang1,3, Shamus Toomath1, Marti Cabanes-Creus6, Catriona McKenzie3,4, James Kench3,4, Avik Majumdar2,3, Mark Gorrell3,5, Geoffrey McCaughan2,3,5, Michael Crawford1,2, Carlo Pulitano1,2,3.
1Centre for Organ Assessment Repair and Optimisation, Royal Prince Alfred Hospital, Sydney, Australia; 2Australian National Liver Transplantation Unit, Royal Prince Alfred Hospital, Sydney, Australia; 3Faculty of Medicine and Health, University of Sydney, Stdney, Australia; 4Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, NSW Health Pathology, Sydney, Australia; 5Centenary Institute, Sydney, Australia; 6Translational Vectorology Unit, Children's Medical Research Institute, Sydney, Australia
Introduction: Biliary strictures after liver transplantation are hypothesised to result from an imbalance between biliary injury and biliary regeneration. Evaluation of biliary regeneration could, in theory, identify grafts likely to develop a biliary stricture. Assessment of biliary regeneration before transplantation is currently not possible due the 24-hour delay in cholangiocyte proliferation. We have developed a method of long-term ex-vivo normothermic machine perfusion (NMP) that could support grafts beyond 24 hours. This study was performed to investigate biliary regeneration during long-term ex-vivo NMP.
Methods: Human livers unsuitable for transplantation were perfused at normothermia beyond 24 hours. Long-term perfusion was achieved using a modified commercial system including dialysis, hormonal and nutritional support. Serial biopsies of the bile duct were collected throughout perfusion for histopathology. Biopsies were examined for presence of biliary epithelium and compared between time-points. Bile biochemistry was also measured.
Results: Eleven grafts were evaluated using long-term NMP up to 13 days. Grafts were unsuitable for transplantation due to medically unsuitable donor (n=2), steatosis (n=2) and donation after circulatory death (n=7). Eight grafts (73%) had complete biliary epithelial loss within 24 hours reperfusion. By 144 hours perfusion, biliary epithelium was identified in seven grafts (88%) suggesting re-epithelisation. Presence of epithelium was not correlated with bile pH or glucose.
Conclusions: This is the first study to demonstrate biliary regeneration after 24 hours of NMP. Long-term NMP has the potential to assess biliary regeneration and identify grafts likely to develop biliary stricture after transplant. Additional biomarkers for biliary regeneration are being investigated.
right-click to download
