1. Why transplant islet cells instead of the whole pancreas?

In Type I diabetes, islet cells are mistakenly destroyed by the body’s own immune system. However, the rest of the pancreas continues to work efficiently, producing special enzymes that aid in the digestion of the intake of food. Although there have been dramatic improvements in the success rate of pancreas transplantation and the procedure is now covered by Medicare, there are still risks associated with whole organ transplantation:

  • Pancreas transplantation is a major surgical procedure
  • If the patient experiences any complications, additional surgery may be required
  • If the pancreas fails, it would need to be removed

For a number of patients, however, pancreas transplantation is a beneficial and viable option for reversing diabetes and for helping to eliminate the progression of diabetes-related complications.

2. What major challenges need to be overcome before islet cell transplantation can be offered to all patients?

There are three basic challenges that remain before islet cell transplantation can be offered to all people living with diabetes. The first is to transplant without the use of long-term immunosuppression (anti-rejection drugs) and ultimately achieve tolerance of transplanted islets. In an effort to transplant islets without these powerful drugs, scientists are:

  • developing specifically-targeted drugs that do not harm the islet cells or pose a long-term health risk to the patient
  • determining ways to prevent a loss of islets during separation and transplantation
  • trying to make islets stronger using “self protection” through genetic engineering
  • encapsulating islets within a protective barrier

The second challenge is to obtain enough cells to treat everyone with diabetes. Once safe and effective treatments are identified, the fact remains that there will not be enough available islet cells to cure everyone with diabetes. Several avenues under investigation include:

  • making islet cells resistant to damage during isolation and transplantation through genetic and molecular techniques.
  • genetically engineering insulin-producing cells.
  • developing insulin-producing cells from pancreatic stem cells.
  • modifying non-human cells for clinical application.

The last challenge is to prevent the recurrence of diabetes after a patient receives a transplant. To prevent the recurrence of diabetes, scientists are developing methods to re-educate the patient’s immune system to accept the donated cells as “self.”

3. How is the isolation process performed?

The isolation process begins with the preparation of a donor pancreas. The organ is slowly injected with special digestive chemicals and then placed in the Ricordi Chamber, which contains glass beads. The chamber is shaken gently and the pancreas progressively breaks down into smaller and smaller pieces.

A very fine screen divides the chamber, allowing only pieces that are half a millimeter or smaller to pass through. A pump pushes the solution through the machine and keeps the flow going in one direction.

Heating coils are used to raise the temperature of the digestive solution during what is called the recirculation phase. In the recirculation phase, the digestive enzymes are circulated through the chamber many times, slowly dissolving the tissue around the islet cells.

In the dilution phase, fresh solution that does not contain digestive enzymes is circulated through the system to gradually slow the break-down process. Cells are collected and purified using a special method that leaves the healthiest islets on top. The islets are then cultured, inspected, and allowed to rest overnight. Before being infused into a patient, they must pass final quality assurance inspections.