Pancreatic Islet Cell Transplantation - A Novel Approach to Improve Islet Quality and Engraftment

Diabetes mellitus (DM) type I is a disease that has significant social and economical impact. The prevalence of the disease in the United States is about 120,000 in individuals aged 19 or less and 300,000 to 500,000 at all ages and 150 million worldwide.

So far there are no mechanical devices able to effectively adjust the dose of insulin injected according to the serum glucose in patients with DM. This leads to less than perfect sugar control, with episodes of hypoglycemia. Successful pancreas transplantation averts the need of insulin administration.

The emerging alternative to whole organ pancreas transplantation is pancreatic islet cell transplantation (ICT). The process is based on the enzymatic isolation of the pancreatic islets from an organ procured from a cadaver donor. The islets obtained are injected into the liver in the recipient via percutaneous catheterization of the portal venous system. This procedure allows the selective transplantation of the insulin-producing cell population avoiding open surgery as well as the transplantation of the duodenum and the exocrine pancreas and their related morbidity.

The initial efforts with ICT had only modest results. The immunosuppression regimen was similar to the one used in solid organ transplantation, based on high dose steroids and calcineurin inhibitors - both agents with diabetogenic effects. The results improved markedly with the changes in the manipulations of the islets, and the change in immunosuppression thus avoiding the higher doses of steroids and using sirolimus, tacrolimus and daclizumab initiated by the investigators group at the University of Alberta in Edmonton, Canada. Their protocol requires in general two islet cell infusions in order to attain the critical cell mass necessary to achieve insulin-independency. The changes in treatment were adopted as the Edmonton Protocol, which is used in several transplant centers, worldwide.

Isolation of the islets from donor pancreata will occur in the Baylor University Medical Center Islet Cell Processing Laboratory (ICPL). The islet cell infusion is performed in the Interventional Radiology Suite at Baylor University Medical Center or Baylor All Saints Medical Center by an interventional radiologist. The procedure takes place in a suite designed for invasive procedures using sterile technique with access to general anesthesia if necessary. Following the procedure the patient is observed in the Interventional Radiology recovery area for as long as necessary as determined by a Physician and then transferred to the Transplant Service for an overnight stay. After recovery, the patient is admitted to the hospital on the Transplant Service for a 1-2 day observation.

The focus of the research in the ICT is centered on the development of a safe and effective procedure that will eventually replace surgical pancreas transplantation together with an ideal immunosuppressive regimen that provides safe and effective prevention against rejection, while minimizing the adverse events associated that negatively impact transplant recipient's quality of life.