What Are Islets?
Islets, more correctly called Islets of Langerhans, are collections of cells within the pancreas. Islets contain beta cells, which produce insulin and are the cells which are destroyed by the immune system in type 1 diabetes. Insulin is required to control blood glucose levels and without sufficient insulin the glucose levels rise resulting in diabetes. People with type 1 diabetes must therefore traditionally inject insulin several times per day to try to keep blood glucose levels stable.
What Is An Islet Transplant?
Islet can be taken from donor pancreas glands, purified in a laboratory and injected usually into the liver of people with type 1 diabetes. The hope is that these islets then produce enough insulin to control the blood glucose levels without the need for insulin injections.
Why Are Islet Transplants Not Being Used Routinely?
There are significant problems with islet transplants which very much limit their usefulness for the majority of people with type 1 diabetes. These are:
- People who have had islet transplants are required to take powerful drugs to suppress the immune system. This is to try to prevent the immune system from attacking and damaging the transplanted islets. These drugs have the potential to cause serious side effects such as infection and cancer.
- Only a proportion of islet transplants will result in the production of sufficient insulin to allow people to stop insulin injections. In addition, the majority of islet transplants will eventually fail. Information from the USA shows that only around 14% of patients will be free of insulin injections 2 years after an islet transplant.
- The supply of donor pancreas glands from which islets can be obtained is limited.
- The procedure of injecting the islets into the liver can sometimes cause some bleeding internally.
Despite these problems, islet transplantation, or perhaps stem cell transplantation does offer hope for the future particularly if a more acceptable way can be found to prevent damage to these cells by the immune system.
So Who Is Suitable For An Islet Transplant?
Islet transplants are currently recommended only for people with type 1 diabetes who are having extreme problems controlling their diabetes mainly due to frequent and severed hypoglycaemia which is seriously interfering with quality of life and which cannot be treated by any other means. Islet transplants have been shown to help stabilise blood glucose values and improve quality of life in these circumstances even if insulin injections are still required.
If you think you might be eligible for an islet transplant you should discuss this with your healthcare professional. Healthcare professionals wishing more information should write to:
Islet Project Coordinator
Is Islet Cell Transplantation Suitable For People With Type 2 Diabetes?
People with Type 2 diabetes are not being considered for islet transplants. Type 2 diabetes typically arises because of insulin resistance (where the body becomes resistant or less sensitive to its own insulin) and adding extra insulin-producing cells would not necessarily be of benefit.
Where Are Islet Transplants Being Performed?
There are six centres which have received funding from the Department of Health to provide islet cell transplants; they are:
• Oxford Radcliffe Hospitals NHS Foundation Trust
• Royal Free Hospital, London
• King’s College Hospital, London
• Newcastle-upon-Tyne Hospitals NHS Trust
• North Bristol NHS Trust
• Central Manchester and Manchester Children’s NHS Trust
Currently islet transplants are being offered in the first three centres listed, with the remaining three centres offering transplants from 2009. It is also hoped that a centre will be opened in Edinburgh in April, 2009.