Outcomes

What is the Success Rate for Islet Transplants?

The success rate of islet transplants has recently increased markedly since the first one was performed at the University of Minnesota in 1974.  The University of Edmonton in Alberta, Canada, in 2000 announced insulin independence in 7 of 7 patients following repeated transplantation of islets prepared from two to four donor pancreases in 2000. These findings have been confirmed at more than 5 institutions worldwide, including the University of Minnesota.

We have also undertaken separate islet transplant trials at the University of Minnesota using next-generation protocols.  These protocols were designed to achieve insulin independence after only one islet transplant. Single-donor islet transplants at the University of Minnesota have successfully reversed diabetes and restored freedom from insulin injections in 15 of 17 patients.  These results demonstrate a successful transplant, normalizing blood glucose into the 70-120 milligrams per deciliter of blood range. The six patients featured here experienced this change with their transplant.

Some recipients have very good function, while other patients may have occasional blood sugar levels over 180 mg/dl. Freedom from insulin reactions is typically achieved immediately after islet transplant. A second islet transplant is considered only if the first does not stop the need for insulin injections. Patients may also experience rejection of a well-functioning islet transplant.  It is unknown whether islet transplant function can be maintained long-term. Two of six patients are now insulin independent for 3 years after a single islet transplant.

What are the Risks of an Islet Transplant?

Although islet cell transplantation is being developed as a safe alternative to pancreas transplantation, people who participate in islet transplant trials may have more problems resulting from study participation than if they continued insulin treatment alone. Islet cell transplantation is an experimental treatment. As with any experimental treatment, there is a risk that rare or previously unknown complications can occur.

There are two principal types of risks associated with islet cell transplantation:

1. First, the risks associated with the transplant procedure itself. These risks include slowed breathing from the anesthesia, severe bleeding, blood clots, abnormal liver function, accidental injury to organs, infection, decrease in blood pressure, pain, extra exposure to x-rays, allergic reaction to contrast dye, and very rarely, death.

2. Second, there are risks associated with the use of anti-rejection drugs, also known as immunosuppressive drugs or immunosuppressants. These drugs are needed for all kinds of transplants.  Immunosuppressive drugs must be taken to prevent the recipient’s body from rejecting the transplant. Antirejection drugs may weaken the recipient’s own immune system, which can lead to serious infections and even cancer.

What are the Benefits of an Islet Transplant?

If successful, the transplanted islets will produce enough insulin so that the transplant recipient will no longer need to take insulin shots or use an insulin pump.  A successful transplant will also control blood sugar levels very tightly and will prevent insulin reactions.  If the transplant is partially successful, the recipient may benefit from more stable blood sugar control, needing less insulin, with fewer insulin reactions.  Because improved control of blood sugar can slow the complications of diabetes, islet transplant recipients may benefit whether their transplant is successful or partially successful. Preliminary studies suggest that islet transplants improve quality of life. Larger studies monitoring development and progression of diabetes complications and quality of life in more transplant recipients for longer durations are needed to assess the true benefits of islet transplantation.