“Transplantation only in complicated cases”
Torbjörn Lundgren is a senior physician at the Department of Transplantation Surgery at Karolinska University Hospital and affiliated to CLINTEC at Karolinska Institutet. Here, both full pancreas transplants and transplants of insulin-producing cells from the islets of Langerhans are performed on patients suffering from diabetes.
How many transplants are performed in Sweden each year, and on who?
“In total, around 30 pancreas transplants, plus the same number of transplants of islet cells, are performed in Sweden each year. Both methods are niche treatments for those patients who have considerable problems with their type 1 diabetes.”
How does it work?
“The vast majority of pancreas transplants are performed in conjunction with a kidney transplant. These are patients whose kidneys have failed as a result of their diabetes and it is then a good opportunity to transplant a pancreas from the same donor, thus eliminating the need for any further immunosuppressants. Transplants of islet cells, in which only the insulin-producing parts of the pancreas are transplanted, are considerably more straightforward as these can be injected directly into blood vessels supplying the liver, where they attach and produce insulin. However, this method is considerably less effective than a full pancreas transplant, meaning that islet cell transplants are only recommended for patients with a moderately large need for insulin-replacing tissue but who have major problems with low blood sugar. Even transplants of islet cells require immunosuppressants.”
What does the future of diabetes-related transplants look like?
“Currently, we are limited by access to organs and cells. Work is underway in an attempt to grow cells and, in the best-case scenario, it should be possible to develop cells that do not require immunosuppressants. Islet cell transplants could then become a more widespread treatment. Another method to avoid immunosuppressants might be to place cells in a chamber that keeps the immune system out but that allows nutrients in and insulin out. Research into these types of solution is ongoing.”
This is how it works: food, blood sugar and insulin
The body needs a relatively stable level of blood sugar (glucose) for use as fuel for areas such as the muscles. If this level is ether too high or too low, the effects can be unpleasant or even dangerous. Too little blood sugar in a healthy individual, something that may occur after intensive exercise or fasting, will cause the alpha cells of the pancreas to produce glucagon, a hormone that in turn causes the liver to produce glucose.
After a meal, blood sugar levels will instead rise and the beta cells of the pancreas immediately respond by secreting the hormone insulin, which reduces blood sugar by causing the liver to absorb and store glucose.
Diabetes disrupts this system, leaving blood sugar levels too high. Different types of disruption lead to different types of diabetes.
Treatments for diabetes are intended to achieve as close to a normal blood sugar regulation as possible. This is because excessive blood sugar levels over long periods lead to secondary diseases such as eye damage, renal failure, nerve damage and foot ulcers. It is therefore desirable to reduce blood sugar through diet, exercise and drug treatments. Blood sugar deficiency is a side-effect, primarily of insulin therapy, that can lead to discomfort in the form of hypoglycaemia or, in the worst case, insulin coma with possible brain damage.
Sources: Wikipedia, Swedish Diabetes Association
Text: Fredrik Hedlund, first published in Swedish in Medicinsk Vetenskap No 2/2018.