What is islet autotransplantation?

Islet transplantation can be used for patients with diabetes (islets from a donor) and when patients have their pancreas removed for the treatment of chronic pancreatitis.

The Freeman hospital already performs both islet cell transplants and whole pancreas transplants from organ donors . The surgical removal of the pancreas will automatically cause diabetes, because the islets scattered within the pancreas are the only site of insulin production in the body.

Islet transplantation is used for diabetic patients and the islets are separated from another person’s pancreas and injected into the patient . For islet autotransplantation, the same methods are used to isolate and transplant the islets but the islets are isolated from the patient’s own pancreas, rather than a donated pancreas. 

Because the patient’s own islets are being transplanted, the body will not see the tissue as ‘foreign’ as is the case with donated tissue from another person and this will avoid problems associated with rejection.

This means that the powerful drugs that diabetic patients use to prevent the body rejecting the donated tissue are not required. 

Additionally, the islet autotransplantation is done at the same time as the removal of the pancreas, with no ‘waiting list’ for a suitable donor.

If successful, islet autotransplantation will prevent you from having to inject yourself with insulin.  In many cases, although the islets are working, the numbers that are isolated and transplanted are often too small to allow you to be completely free of insulin injections.

However, the doses of insulin necessary to control blood glucose levels tend to be much lower than if the islet transplantation had not been done. Even if you make some of your own insulin this will be of great benefit in the long-term giving you better control of your blood glucose.

How are the islets isolated?

During the operation the pancreas will be removed and then taken to the islet isolation laboratory.

The pancreas is then injected with an enzyme called collagenase, which digests it and separates it into acinar tissue and islets.

The pancreas is placed in a specialised chamber and a solution is circulated through it. This special chamber is in a circuit containing the digestion fluid and this is known as the digestion process. 

The digested pancreatic tissue is then washed several times to remove any remaining enzyme and dead acinar tissue. Samples are then taken to allow the number of islets to be counted and their size measured.

This is important, as it allows a calculation to be made about the total amount of islet tissue which is going to be transplanted. The islets are then put into an infusion bag and taken back to theatre to be transplanted into your liver.

How are islets transplanted?

Islets are normally scattered within the pancreas. However, as your pancreas will be removed, an alternative place to transplant the islets into has to be found. 

Information gathered from studies around the world has shown that the best pace to transplant the islets is into the liver.

In order for your islets to be infused into your liver, the surgeon will place a small tube into one of the blood vessels that supplies the liver with blood. Once this is in place, the tube is attached to the infusion bag containing the islets.

These are then infused slowly into your liver while the anaesthetist keeps a careful check on the blood pressure going into the liver.

The whole process from the time the pancreas arrives in the laboratory to the time the islets go back into your liver takes between two and three hours.

Once the islets have been infused the operation is completed and your wound will be closed. You will then be transferred to the recovery room and then to the intensive care unit.

Is it definite that the islets will be isolated from my pancreas?

The methods used for isolating islets from the pancreas have been undertaken for many years and scientists with training and experience will be performing this part of the procedure.

If the pancreas has been severely damaged by the chronic pancreatitis process or you have had a previous drainage operation it may not be feasible to inject the enzyme/protein required to digest the pancreas and it will then be impossible to recover any islets to transplant back into your liver.

Every effort will be made to try to isolate the islets but sometimes this is just not possible. Also rarely there are technical failures with the isolation equipment which can lead to no islets being isolated but reasonable steps will be taken to try and keep this risk to a minimum.

Unfortunately, it is not possible to tell whether the islet isolation will be successful until the pancreas has been taken back to the laboratory and the isolation process is completed. Your surgeon and or nurse specialist will be able to discuss the possibility of this happening to you.

Is islet autotransplantation always successful?

The aim of islet autotransplantation is to preserve and restore as much of the insulin producing islet tissue as possible.

Over time, if left untreated, the damage from your chronic pancreatitis will cause your pancreas to “fail” and you will most likely develop diabetes anyway.

You will need to take injections of large doses of insulin to control your blood glucose levels and will have to prick your finger 4-5 times a day to check your blood glucose.

If the islet autotransplant works and you receive enough islet cells, the transplanted islets should produce enough insulin to allow you to maintain your normal blood sugar levels without having to inject insulin.

In some cases, the islets work partially, which means that you will need a little bit if insulin to “top-up”, but your blood sugar levels will be quite stable and much easier to control.

Even having partial function means that you are at a much lower risk of low blood glucose and that diabetes is much easier to control.

If the autotransplant fails, or we are not able to isolate the islets from your pancreas, you will be completely reliant on insulin. Without insulin you cannot live it is a vital hormone to maintain life.

In the UK and abroad, islet autotransplantation has had very good success, with most patients achieving full or partial function of their transplant. However, it is important to remember that there is no guarantee that once the islet autotransplantation has been performed that your islets will function normally. 

It is usually the case that the islets take some time, generally 2 to 3 weeks before they start to secret insulin fully and in some cases there is a further improvement a lot later (sometimes as long as 1 and 2 years).

During that time, you will have to inject yourself with insulin, but as your islets start to work, the dose you need to inject will gradually decrease