Background: Owing to advances in both immunosuppressive protocols and pancreatic islet isolation techniques, insulin independence has recently been achieved in type 1 insulin-dependent diabetics (IDDM) via pancreatic islet transplantation (PIT). Although the dissemination of immunosuppressive protocols is relatively easy, transferring the knowledge and expertise required to isolate a large number of quality human islets for transplantation is a far greater challenge. Therefore, in an attempt to centralize the critical islet processing needed for islet transplantation and to avoid the development of another islet processing center, we have established a collaborative islet transplant program between two geographically distant transplant centers.
Patients and methods: Eleven consecutive type 1 IDDM patients with a history of severe hypoglycemia and metabolic instability underwent PIT at the Methodist Hospital (TMH) in Houston, Texas, utilizing pancreatic islets isolated at the Diabetes Research Institute (DRI) at the University of Miami in Miami, Florida between January 1, 2002 and June 31, 2003. Forty-one pancreata have been procured in the Houston area and have subsequently been transported for isolation at the DRI following enzymatic ductal perfusion by the automated method (Ricordi chamber). Following purification the islets were immediately transported back to TMH in Houston and transplanted via percutaneous transhepatic portal infusion. Immunosuppression regimen consisted of sirolimus, tacrolimus, and daclizumab.
Results: Following harvesting, donor pancreata arrived at the DRI for initiation of the isolation process within 6.5 hours of cross-clamping (median time 5.4 hours; range 4.8 to 6.5 hours). The islets were immediately transported back to TMH for final sterility and viability tests and transplanted via percutaneous transhepatic portal vein infusion. The harvesting of 41 pancreata has yielded a number of pancreatic islets sufficient for transplantation (>5000 IEQ/kg recipient body weight) 26 times (63% of harvested pancreata). Thus far, three patients have received three PITs and eight patients have received two PITs. Six remain insulin independent. All have experienced a decrease in serum hemoglobin A(1c) levels, and both basal and stimulated C-peptide levels have increased. There have been no major complications related to the procedure or the immunosuppressive regimen used.
Conclusions: Our series demonstrates that pancreatic islets isolated at a remote isolation center can successfully and safely be used for PIT and the achievement of insulin independence.