Background: Islet transplantation is a promising option for treating type 1 diabetes. However, multiple transplantations are often required to achieve insulin withdrawal owing to limited islet volume and early islet damage after transplantation. In this study, we evaluated the effects of co-transplantation[A1]  with human amniotic epithelial cells (hAECs) on an islet engraftment.

Method: Diabetes was induced in Lewis rats using streptozotocin 7[A2] –8 days before transplantation. Six-hundred IEQs[A3]  syngeneic islets isolated from Lewis rats and 4000 IEQs allogeneic islets isolated from Wister/ST rats were transplanted either alone or mixed with 1 × 106 hAECs via the portal vein. Blood glucose levels were measured periodically after transplantation.

Results: In the syngeneic transplantation experiment, the blood glucose trends were significantly [A4] low in the co-transplantation group[A5] . In the allogeneic transplantation experiment, we did not observe long-term islet engraftment in both groups. However, the period of normalization for blood glucose levels was prolonged in the co-transplantation group compared with that in the alone islet group.

Conclusion: Although co-transplantation with hAECs improved early islet engraftment, the barrier of allogeneic rejection could not be overcome. The promotion mechanism of islet engraftment in syngeneic co-transplantation, improvement in short-term allogeneic islet engraftment, and the effects of hAECs on innate and acquired immune systems require  further investigation.