29 July 2008

Artificial pancreas just years away

Researchers working on an artificial pancreas say they are just a few years away from a nearly carefree way for people with diabetes to monitor blood and inject insulin as needed.

Researchers working on an artificial pancreas believe they are just a few years away from a nearly carefree way for people with diabetes to monitor blood and inject insulin as needed.

They believe they can link two current technologies - continuous glucose monitoring and insulin pumps - into a seamless package.

Such a mechanical pancreas could greatly reduce the need for finger sticks and injections of insulin that diabetics must now endure several times a day, researchers told a meeting this week at the National Institutes of Health.

"I think we are on the brink of a first-generation artificial pancreas," said Dr Roman Hovorka of Britain's University of Cambridge, who is testing some experimental devices with components by Abbott Laboratories and Medtronic, the No. 1 maker of insulin pumps and continuous monitors.

Device ready for home use
Hovorka's team has been testing devices in patients with type-1 diabetes, an autoimmune disease caused when the body mistakenly destroys the insulin-making cells in the pancreas.

A continuous glucose sensor is implanted under the skin, and transmits blood sugar readings to a monitor. A computer calculates the right dose of insulin, which is delivered by an insulin pump - something many patients already wear.

His team is ready to send some patients home with the device, but has to work out the logistics of keeping a nurse full-time in each volunteer's home, just in case.

US Food and Drug Administration regulators are working closely with the researchers to ensure they design studies in a way that can lead to quick review, said Dr Aaron Kowalski of the Juvenile Diabetes Research Foundation, which funds many of the artificial pancreas study teams.

System may help children with Type 1 diabetes
For people with type-1 diabetes, scrupulous care is needed to avoid swings in blood sugar levels. If levels go too low, the patient can pass out and die. When blood sugar goes too high, it damages capillaries and eventually organs.

Patients whose sugar levels regularly creep up suffer gradual and usually symptomless damage until they go blind, or lose kidney function, suffer heart damage or perhaps lose a limb.

"If we could prevent one person from dying due to hypoglycemia, that would be a triumph," Kowalski said.

Such a system would be especially helpful for children with type-1 diabetes.

"Parents are waking up every single night, often multiple times, to test their children's blood sugar," Kowalski said. "And often it is high or low. Overnight control might be the easiest part of the closed loop. We think we can do this now."

Wireless technology used
Dr Bruce Buckingham, of California's Stanford University and Packard Children's Hospital, agreed the easiest test of an artificial pancreas might be at night, when people are not eating, drinking or moving about, and thus their bodies are not making changing demands for insulin.

"You can go step by step," Buckingham said.

The computer could be held in a device the size of an iPod, the researchers agree. "For a fully, completely automated waterproof, all-environment system - that may be more than six years," Buckingham said.

While a traditional insulin pump has several feet of tubing, Insulet Corp has a device that sticks to the skin, with a tiny tube inserted in the upper arm or stomach.

Medtronic has wireless technology to transmit glucose readings, another key component connecting the blood sugar monitor and the insulin pump. People can now wear both continuous glucose monitors and insulin pumps, but they do not communicate with one another and so patients must manually read the sugar levels and operate the pump.

The insulin pump also must be able to quickly shut off if blood sugar falls too low, the experts agree.

About 24 million Americans have diabetes, with Type 1 accounting for five to 10 percent of diagnosed cases. Insulet estimates 23 percent of Type 1 patients use pumps and values the market at $4.3 billion if all did.

But the experts say there is likely a market for artificial pancreas systems among people with the most severe cases of type 2 diabetes, who must also take insulin. – (Reuters Health, July 2008)

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