Background
Benign bile duct stricture is common in surgical practice. The complications of late stricture formation and biliary sepsis still occur in bile duct reconstruction. Many biological and artificial materials have been used to replace the damaged bile duct to avoid bilio-enteric anastomosis, which bypasses the biliary sphincter mechanism. Amniotic epithelial (AE) cells are known to have unique characteristics, such as low-level expression of major histocompatibility complex antigens and a less restricted differentiation potential. AE cells differentiate into different cell types from all three germ layers, including cardiomyocytic, myocytic, osteocytic, adipocytic (mesodermal), pancreatic, hepatic (endodermal), neural, and astrocytic (neuroectodermal) cells in vitro, suggesting a promising candidate to reconstruct the damaged bile duct.
Material and Method
Human amniotic grafts (as a source of stem cells) with or without vascularized peritoneomuscular flap were used to repair damaged bile ducts (non-circumferential and circumferential bile duct loss) in a dog model.
Results
Non-circumferential bile duct loss appeared to be satisfactorily repaired using amnion graft alone. However, circumferential duct loss was not adequately repaired with amnion graft alone, but it was adequately repaired using amnion graft with a vascularized peritoneomuscular flap. In adequately repaired cases, histological examination demonstrated that the biliary mucosal endothelium had grown over the amniotic membrane graft.
Conclusions
Collectively, the data presented here suggest that the use of human amnion as a source of amniotic stem cells provides a very promising tool for tissue reconstruction.

Keywords: Prosthesis Implantation, Postoperative Complications, Epithelial Cells - transplantation, Dogs, Common Bile Duct - surgery, Cell Differentiation - physiology, Anastomosis, Surgical, Amnion - transplantation, Reconstructive Surgical Procedures - methods, Stem Cells - physiology, Transplants