Mechanical solution to type 1 diabetes in sight.

Mechanical solution to type 1 diabetes in sight.

Building an “artificial pancreas” to replace the patient’s insulin-producing organ after it fails is an important theme of diabetes research. There are two very different approaches to the artificial pancreas. The biological approach – to develop a new organ through cell therapy and tissue engineering – is the subject of a separate article. The other, covered here, is electronic and mechanical: to develop devices that monitor glucose levels and pump insulin into the patient as and when the hormone is needed.

A leading centre of artificial pancreas research is at Cambridge university’s Institute of Metabolic Science, led by Roman Hovorka. His work is funded by two big charities, Diabetes UK and the Juvenile Diabetes Research Foundation, as well as government agencies.

This year, Dr Hovorka’s team carried out the world’s first clinical trial, in which patients used an artificial pancreas at home without medical supervision. The 24 participants used the device over periods of four weeks at night, when there is particular risk of their blood glucose levels falling too low. Alasdair Rankin, research director of Diabetes UK, says: “After years of scientists discussing the possibility of an artificial pancreas, we are now at the exciting point where people are using them in their homes.

“This means we have reached a landmark in the development of a technology that offers real hope for a future where type 1 diabetes does not mean having to think constantly about the balance of blood glucose levels and insulin, or having to face a much higher risk of dying early.”

Dr Hovorka is working with Cambridge Consultants, the product development company, on a new version of the artificial pancreas. It will link a continuous glucose meter – implanted just below the skin to read blood sugar levels every minute or so – via Bluetooth to a smartphone or tablet computer. This in turn controls the insulin pump that delivers the hormone into the bloodstream through a catheter.

“Trialling the system in a natural setting over a longer time period is the next stage in making the system widely available,” said Dr Hovorka. “To do this, it must work completely autonomously.”

Dr Rankin expects the system to be used only at night for the time being. “However, as the technology progresses, we expect it to make type 1 diabetes an increasingly manageable condition, until eventually we will reach the point where people might check their artificial pancreas when they get up in the morning and then not have to think about their diabetes for the rest of the day,” he says.

Several medical device companies are working on the technology, both independently and in collaboration with JDRF. Although the insulin pumps now on the market require patients to set their dosing levels, they are becoming easier to use.

The latest one from Medtronic, called Paradigm Veo, has a “low glucose suspend” mechanism that automatically stops insulin delivery when glucose levels fall below a predetermined threshold, to prevent severe hypoglycaemia.

At the same time, the sensors that monitor glucose levels in the blood are improving. JDRF and Medtronic are collaborating to develop a device that incorporates two independent measurement techniques. It will combine a glucose oxidase sensor – an electrochemical detector commonly used in today’s monitors – with a new optical sensor, to provide more accurate readings.

“The next step will be a ‘treat-to-range’ system that deals with both high and low glucose levels,” says Sarah Johnson, JDRF UK policy director. “Then the idea will be to tighten the range, so that eventually we get a ‘treat-to-target’ device that maintains the optimum levels the whole time. That really will be an artificial pancrea

Prof. HL