Two hormones are better than one?

Exciting results from one of the key research teams in the JDRF Artificial Pancreas Consortium have been published today in the journal Science Translational Medicine.

The team, based at Boston University and Massachusetts General Hospital in the USA, is working on an artificial pancreas or closed loop system that can automatically regulate blood sugar levels by not only giving insulin according to the body’s minute to minute needs, but also administering glucagon automatically as well.

Glucagon is a hormone produced naturally by the pancreas that has the opposite effect to insulin – it can increase blood glucose levels. In people without type 1 diabetes the body can finely balance glucose levels in the body by releasing exactly the right amount of insulin or glucagons at any time. The team in Boston is trying to replicate this ability to fine tune glucose levels using a mechanical closed loop system.

The research team, led by Dr Edward Damiano, has developed a computer programme that can use blood glucose readings from an intravenous glucose monitor to dictate when doses of a fast-acting insulin analogue (lispro) and of glucagon should be delivered. The doses of insulin and glucagon were each delivered through commercially available insulin pump devices.

Eleven patients participated in this initial study. They all stayed in hospital for the 27 hour experiment, and during the day they each had three standardised, high-carbohydrate meals.

In the first phase of the study, six of the patients achieved an average blood glucose concentration of 7.8mmol/l, without any hypoglycaemia. But the other five patients did experience hypoglycaemia, which the doses of glucagon given by the system were unable to prevent.

When the research team analysed the results from this first phase of the trial they realised that the people who had experienced hypoglycaemia absorbed insulin more slowly than the value that the system had been designed to expect. The researchers then altered the model of insulin absorption used by the computer programme and asked all 11 of the trial participants to try the system again, repeating the same study design.

This time, none of the participants experienced hypoglycaemia, and the average glucose concentration was still in the target range (9.1 mmol/l).

Rachel Connor, Research Relations Manager at JDRF commented ‘The research team has shown that an artificial pancreas system including glucagon can help to achieve tight glucose control without hypoglycaemia. This exciting ‘proof of principle’ study shows just how sophisticated closed loop systems could become in the future.’

Click here for more information on the artificial pancreas project.