The benefit of insulin and glucagon in an artificial pancreas

This study examined whether the combination of glucagon and insulin in an artificial pancreas is more effective compared to insulin alone.

An insulin pump allows a patient to enter in the carbohydrate content of a meal and the pump releases insulin based on this. A continuous glucose monitor is a device which allows patients to view their blood glucose (sugar) levels in real-time. An artificial pancreas is a system composed of an insulin pump and a continuous glucose monitor. The continuous glucose monitor sends information on blood glucose levels to the insulin pump wirelessly. The insulin pump then releases insulin in a glucose-dependent manner. The artificial pancreas is still undergoing clinical trials, and is not currently used in diabetic patients.

Insulin and glucagon are hormones which are released from the pancreas. Insulin reduces blood glucose levels and glucagon increases blood glucose levels. A dual-hormone system is a combination of insulin and glucagon. This may provide greater control of blood glucose levels at night compared to a single-hormone system (insulin alone). In particular, glucagon may prevent low blood glucose levels at night.

This study compared the effect of a dual-hormone artificial pancreas, a single-hormone artificial pancreas and a regular insulin pump on control of blood glucose levels at night. 

This study involved 28 type 1 diabetes patients. Each participant received three treatments at home. The three treatments included regular insulin pump therapy, a dual-hormone artificial pancreas and a single-hormone artificial pancreas. Treatments were carried out for two days each and separated from each other by three days. During each treatment, participants performed exercise on the first night and ate a high carbohydrate/high fat meal on the second night. Participants received the insulin treatments from 9 pm to 7 am.

In 50% of participants receiving the dual-hormone artificial pancreas, blood glucose levels were in the target range (4-8 mmol/L) 81% of the time. Blood glucose levels were in the target range 76% of the time in participants receiving the single-hormone artificial pancreas. The blood glucose levels were in the target range less often in participants on the regular insulin pump (47% of the time).

14 participants receiving regular insulin pump therapy experienced hypoglycemia (dangerously low blood glucose levels). 6 participants receiving the single-hormone artificial pancreas experienced hypoglycemia. 3 participants receiving the dual-hormone artificial pancreas experienced hypoglycemia.

There was no significant difference in blood glucose control or hypoglycemia between the single-hormone artificial pancreas and the dual-hormone artificial pancreas.

This study concluded that a single- and dual-hormone artificial pancreas improved glucose control at night. However, the dual-hormone artificial pancreas is not more effective than the single-hormone artificial pancreas in controlling glucose levels.