The human umbilical cord: A novel substitute for reconstruction of the extrahepatic bile duct

Reconstruction of the extrahepatic bile duct following bile duct injury or defect is one of the most common challenges for hepatobiliary surgeons. There are currently a number of surgical strategies such as biliary-enteric anastomosis, end-to-end anastomosis and autologous tissue substitute. However, sphincter of Oddi dysfunction as well as biliary stricture may occur after surgical anastomosis. Also, insufficient tissue quantity remains a problem associated with the application of tissue substitute. Therefore, considerable attention has been attracted to explore a new replacement material of the bile duct for biliary reconstruction. The human umbilical cord (HUC) is abundant in resource and is convenient to collect, including two arteries and one vein, whose diameters are close to that of the common bile duct. In order to reduce immunogenicity (foreign-body reaction), cells and major histocompatibility complex (MHC) antigens can be removed from the HUC and the remaining tissue (extracellular matrix, ECM) can be used as a scaffold. The HUC provides a rich source of mesenchymal stem cells (MSCs). A current study has demonstrated that MSCs are able to differentiate into biliary epithelial cells in vivo and in vitro with low immunogenicity, which can be used as seed cells. The HUC might be a promising composite material of a scaffold (ECM) and seed cells (biliary epithelial cells), for bile duct replacement in situ without removal of sphincter of Oddi, or biliary stricture. In addition, the patients’ own umbilical cord without any foreign-body reaction can be directly banked for possible future use in bile duct reconstruction. Therefore, we hypothesise that the HUC may be a novel substitute for reconstruction of the extrahepatic bile duct.