Progress towards an 'artificial pancreas'

A developing technology that utilizes computer algorithms to automate insulin delivery is gaining momentum to help those with Type I diabetes that cannot produce their own insulin. An approach to create such an artificial pancreas called a “closed-loop system” was a topic of much buzz at Sunday’s American Diabetes Association conference in Philadelphia.

“Closing the loop is the holy grail for the artificial pancreas,” says Michael Rickels, an endocrinologist at the Hospital of the University of Pennsylvania. “It will happen, the only question is when.”

There are three main parts to a closed-loop system: an insulin pump, a real-time continuous glucose monitor, and the computer algorithm that takes in information from the monitor and calculates the proper amount of insulin to infuse. The goal is to have no patient intervention in the system, improving the accuracy of dosages, and thereby “closing the loop.” The pump and monitor are each about the size of a pager, and while current algorithms are used only on computers, the hope is to one day install software onto a patient’s mobile device.

So how far away are we from having a closed-loop system readily available to patients? William Tamborlane of the Yale School of Medicine joked that parents of diabetic children often ask him about “those artificial pancreas thingamajigs,” and his easy response is that it will hopefully be available in “about five years or so.” Advances are being made in the form of small improvements to each part of the closed-loop system. One issue of both insulin pumps and glucose monitors is the lag time involved in going from tissue to bloodstream, or vice versa.

For instance, current glucose monitors measure levels in the surface layer of skin, which may not reflect blood glucose accurately since there is an inherent delay between the two measures of about 5 to 10 minutes, explains Rickels. The same goes for the lag in insulin delivery, which could prove dangerous for someone whose blood sugar has risen rapidly. One solution that Tamborlane has started to explore is heating up the skin directly under the insulin infusion area to speed up blood flow, and hence, insulin travel time.

For now, patients tested with closed-loop systems have been confined to clinical research centers, under the close supervision of nurses ready to aid whenever an issue arises. But once the bugs have been sorted through, the next step towards advancing this technology is for patients to try them out in their homes under real-life circumstances.

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