Researchers are now focusing on transplantation of pancreatic islets (clusters of insulin-secreting beta cells) rather than transplanting a whole or partial pancreas.
With islet transplants, pancreases from two or three deceased donors are treated with an enzyme that breaks up connective tissue so that islet cells can be separated out for removal. Then the surgeon injects the islets through a blood vessel in the patient's abdomen and into the liver via a small plastic tube (a catheter). Direct injection into the pancreas is not possible because of the risk of inflammation.
The procedure was developed at the University of Alberta in Edmonton, Canada. Several hundred islet cell transplants have been done using the Edmonton protocol.
One year after transplantation, a majority of patients no longer need insulin injections, although they do need powerful immunosuppressant drugs to prevent transplant rejection. However, within five years, most patients are again back on insulin, because the transplanted islets stop working or are damaged by the immunosuppressant drugs.
One possible way to overcome these problems is to obtain a large number of islet cells from just one nonliving donor, which would decrease the risk of rejection. In a 2005 study, researchers treated people who had type 1 diabetes with inflammation-preventing drugs, then performed transplants using islet cells from single donors. In the study, five of the eight patients maintained good blood glucose control one year later, without the need for insulin injections.
In another recent study, Japanese doctors successfully transplanted islet cells taken from a living donor into a woman with type 1 diabetes.
Stem Cell transplants
The shortage of organs from living and nonliving pancreas donors is also spurring research into other means of producing beta cells, either by using donor cells to grow new cells in the lab (culturing human islet cell lines) or by growing beta cells from stem cells. This research is in its infancy, and many more laboratory and animal studies are needed before these techniques can be attempted in humans.