Diabetes

05 March 2018

How does an artificial pancreas work?

Could an artificial pancreas system be the future for diabetics? We investigate.

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We are dependent on our pancreas to release two hormones into the blood: insulin, which enables us to metabolise sugar, and glucagon, which helps raise blood sugar when glucose levels drop too low.

People with diabetes have a compromised ability to produce insulin and glucagon. Their blood glucose levels are too high because their pancreas does not provide sufficient amounts of insulin to help metabolise sugar, or the glucose levels are too low as their pancreas doesn’t produce enough glucagon.

What about pancreas transplants?

Pancreas transplants exist, but in South Africa this procedure is only done in conjunction with a kidney transplant in cases where the kidneys are extremely damaged and failing due to diabetes, says Dr Wayne May, an endocrinologist from Cape Town.

“The other way of doing a transplant is by injecting pancreatic cells in the veins of the liver, but this technique is not done in South Africa, as it is very costly, not always successful, and requires immunosuppressive drugs, which come with their own side-effects,” says Dr May.

While pancreas transplants have improved the lives of diabetics, these patients still need immunosuppressant drugs for the rest of their lives to lower the risk of the body rejecting the organ. The scarcity of organ donors is also a problem.

This means that organic solutions for pancreas replacement are costly and limited. People with diabetes could therefore benefit from a less invasive, widely available treatment. 

insulin pump

The idea of an artificial pancreas system   

Type 1 diabetes is caused by a “faulty” pancreas and type 1 diabetics need to inject insulin daily to regulate their blood sugar. 

The possibility of an artificial pancreas was researched because of the need to improve glucose control in diabetics and to reduce the burden of injecting insulin.

An artificial pancreas system is designed to deliver responsive insulin according to the person’s needs by reading information from a sensor. Clinical trials have shown that users felt positive about this system and that their glucose levels improved, while their risk for hypoglycaemia (low blood sugar attacks) was reduced.

In 2017 the FDA approved the artificial pancreas system and 2016 studies predicted that this device would come onto the market in 2018.

But exactly how helpful and beneficial is this system?

The benefits of an insulin pump device

The better the glucose levels are controlled, the less the risk of long-term diabetes-related health complications such as hyperglycaemia and hypoglycaemia, as well as nerve damage.

While current treatments such as insulin injections and insulin pump devices are very effective at managing diabetes, they are still invasive and there is no guarantee that optimum glucose levels would be maintained, mainly because of human error.

The insulin pump therapy option is less invasive than needles, but still requires that diabetics check their glucose levels at least four times a day. Dr May calls the patient the "brain" behind the operating system, as they are still responsible for controlling the device.

However, the artificial pancreas system promises to provide real-time, continuous glucose measurement through a controlled algorithm, leaving little room for human error. Trials have shown that this method especially benefits young children as it cuts out the need for needles and constant monitoring.

A study has shown that the risk for hypoglycaemia, especially at night when glucose levels plummet, was significantly less in the subjects who used the artificial pancreas system. This lessens the stress in parents with diabetic children.

"I think what we can say is that the artificial pancreas is definitely better than the conventional insulin pump," says Dr Betul Hatipoglu, an endocrinologist at Cleveland Clinic.

But are there downfalls?

While the advantages are considerable, preliminary research did show limitations and disadvantages. There is no doubt that an artificial pancreas system will take a huge amount of responsibility off the diabetic's shoulders, especially when they are still young.

Dr Erika Villanueva from the Division of Endocrinology, Diabetes and Bone Disease at the Icahn School of Medicine, Mount Sinai, New York, says in an article, "A continuous glucose monitor measures glucose level in the tissue fluid, which does not change as quickly as the glucose level in the blood, which can lead to inappropriate dosing of insulin when the blood glucose is too high or too low. Patients would need to carry an additional device (the 'brain'). And it’s currently only available for clinical trials."

Even though the artificial pancreas system is meant to be intuitive and intelligent, technology also makes mistakes. Patients have to be concerned about errors occurring in the pump and sensors of the device. This means that the device isn’t fully automated and that patient involvement is still required.

Instead of managing the condition completely, it still requires calculating and thinking by the diabetic. While the device is not as invasive as needles, scar tissue can still form around the source of the implant.

Such a device would also be costly. In America the device would cost around $6 000 to $9 000 (about R72 000 to R108 560) depending on the medical aid scheme and provider.

"This device is definitely an advance," said Thomas Donner, director of the Johns Hopkins Diabetes Center. According to a major paper on the MiniMed 670G, published in JAMA, patients who used the device for 12 weeks had improved control of their diabetes (better A1C levels, less glucose variability, and no severe low blood glucose or diabetic ketoacidosis, which is a severe complication of diabetes).

Open-loop system still used in SA

Dr May says while we currently have the insulin pump system linked to a glucose sensor available for patients in South Africa, the patient still needs to be the “brain” behind the system.

"In South Africa, we are currently making use of an open-loop system called the Medtronic. Even though the patient still needs to control it, the system has the ability to predict lows and shut off the insulin accordingly.

"But with a closed-loop system, the machine controls the insulin independently of the patient. The machine functions completely on its own. This would be very nice for patients, as they wouldn’t have to monitor or adjust insulin doses, and the risk of highs and lows would be markedly reduced," says Dr May. 

If a closed-loop system were to become available, it would be of great benefit, particularly for parents of young diabetics. 

Image credits: iStock 

 

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Diabetes expert

Dr. May currently works as a fulltime endocrinologist and has been in private practice since 2004. He has a variety of interests, predominantly obesity and diabetes, but also sees patients with osteoporosis, thyroid disorders, men's health disorders, pituitary and adrenal disorders, polycystic ovaries, and disorders of growth. He is a leading member of several obesity and diabetes societies and runs a trial centre for new drugs.

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