Bioartificial Endocrine Pancreas (Bio-AEP) for Treatment of Diabetes: Effect of Implantation of Bio-AEP on the Pancreas

Recently, we described a diffusion chamber for a bioartificial endocrine pancreas (Bio-AEP). Pancreatic islet cells in the Bio-AEP device were isolated from the immune system of the host by an artificial barrier, while nutrients, electrolytes, oxygen, and bioactive secretory products were exchanged across this barrier. This experiment was designed to evaluate whether the diffusion chamber could be useful as a Bio-AEP in the treatment of diabetes. Six streptozotocin (STZ)-induced diabetic rats each received a diffusion chamber containing 8 × 106 MIN6 cells as a xenograft Bio-AEP. In the STZ diabetic rats with Bio-AEPs, a return to normoglycemia was observed up to 30 weeks after implantation, without the use of any immunosuppressant. A gradual increase in the body weight of the rats was also observed. In three STZ diabetic rats, diffusion chambers without MIN6 cells were implanted as a sham operation. The fasting blood glucose levels in these three rats remained higher than 600 mg/dl, after implantation, and they lost weight. Thirty-five weeks after implantation, the pancreata were removed from the rats that underwent xenoimplantation, those that had the sham operation, and the normal control rats. In the sham-operated animals, the exocrine tissues of the pancreata were vacuolated and pancreatic B cells were not seen in the islets. In contrast, in the pancreata from the xenoimplantation, the exocrine tissues were normal, and a few pancreatic B cells were seen in the islets. These results indicated that xenoimplantation using the Bio-AEP might retard the progress of diabetes.