An islet cell transplant is a procedure in which insulin-making pancreas cells (islet cells) are injected into the body. It is an experimental treatment being developed for type 1 diabetes and possibly type 2 diabetes and other forms of diabetes.

If successful, islet cell transplants could enable patients to maintain glucose (blood sugar) levels without insulin injections, while reducing or preventing diabetic complications. Some recipients have remained insulin independent for several years, but most have needed additional islet cell infusions or still need to inject some insulin. The procedure is still under clinical study but may one day replace whole pancreas transplantation, which is more invasive, costly and risky.

The islet cells of the pancreas include the beta cells, which make insulin. The body needs insulin to transport glucose into the cells to be used for energy. Type 1 diabetes develops when beta cells are destroyed or damaged and cannot produce insulin.

Islet cell transplant involves removing beta cells from donor pancreases. In a typical procedure, these fragile cells are injected into a vein and travel to the liver, where they take root and begin producing insulin.

Recipients have to take potentially harmful immunosuppressives for the rest of their lives. Islet cell transplants are available through clinical studies at a few dozen hospitals. Candidates must meet certain criteria for inclusion, such as having type 1 diabetes for more than five years and having severe bouts of uncontrolled glucose despite adherence to the treatment plan.

Researchers have recently reported many advances, including cross-species transplants, use of gene therapy to improve beta cells, reduction in the need for immunosuppressives, and progress in protecting the transplanted cells from the immune system.