(See also Overview of Transplantation.)
Islet cells are the cells in the pancreas that produce insulin, which is the hormone responsible for controlling people's blood sugar levels. Pancreatic islet cell transplantation may be an option for people who have diabetes and whose pancreas cannot make enough insulin.
Transplanting islet cells is simpler and safer than pancreas transplantation, and about 75% of people who receive an islet cell transplant no longer need insulin 1 year after transplantation and may not need it for many more years. However, the long-term success of islet cell transplantation is not yet proved.
Procedure
Islet cells may be separated from the pancreas of a deceased donor. The islet cells are then transplanted by injecting them into a vein that goes to the liver. The islet cells lodge in the small blood vessels of the liver, where they can live and produce insulin. Sometimes two or three infusions are done, requiring two or three deceased donors. Drugs to inhibit the immune system (immunosuppressants), including corticosteroids, are needed to help reduce the risk of rejection
Some people must have their pancreas removed because of disorders such as chronic pancreatitis. Such people will then develop diabetes even if they did not have diabetes previously. After the pancreas is removed, doctors can sometimes harvest the islet cells from the person’s own pancreas. These islet cells can then be transplanted back into the person’s body (autologous transplantation). Because the cells are the person’s own, immunosuppressants are not needed.
Complications
Even if tissue types are closely matched, transplanted organs and tissue, unlike transfused blood, are usually rejected unless measures are taken to prevent rejection. Rejection results from an attack by the recipient's immune system on the transplanted organ, which the immune system recognizes as foreign material. Rejection can be mild and easily controlled or severe, resulting in destruction of the transplanted organ.
Rejection may occur. Doctors detect it by measuring levels of digestive enzymes that are made in the pancreas enzymes and as well as sugar (glucose) and a protein called hemoglobin A1C in the blood (as for diabetes).
Other complications result from the procedure. They include bleeding and blood clots in the vein that brings blood to the liver (portal vein).
