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Experimental Artificial Pancreas Controls Blood Sugar in Diabetics

Depiction of the bi-hormonal closed-loop control system used in the clinical trial. The controller responded to venous blood glucose measured every five minutes using the FDA-approved GlucoScout (International Biomedical) and commanded insulin-glucagon co

Scientists have developed a computerized system for diabetics that takes the guesswork out of controlling their disease. The prototype artificial pancreas monitors and regulates the amount of glucose, or sugar, in the blood of people with type 1 diabetes.

People with type 1, or juvenile, diabetes must keep a watchful eye on their blood glucose levels because their pancreases are not working normally.

The pancreas is an organ that in healthy people secretes insulin to convert glucose into energy. But in people with juvenile diabetes, the pancreas does not produce insulin and blood sugar levels can get dangerously high. Failure to maintain tight control of glucose levels - by measuring blood sugar with a meter and compensating with doses of insulin - can result in serious health complications, including blindness, kidney failure and heart disease.

Edward Damiano, a biomedical engineer at Boston University in Massachusetts, knows firsthand the challenge of managing juvenile diabetes.

"This is a condition that does not take holidays at all," he said. "It's a 24/7 kind of commitment, which is why it's nice for me at this stage of my life to be able to take care of my son at night. But in seven years, he's off to college. This has given me tremendous impetus to try and develop this technology and get it out there and make it available to people with type 1 diabetes before my son goes to college."

Dr. Damiano has partnered with scientists at Massachusetts General Hospital to develop a computer program designed to run a system they call an artificial endocrine pancreas.

The system utilizes existing diabetic technology. The computer program continuously takes in data from a glucose monitor inserted into a patient's vein and calculates the dose of artificial insulin that needs to be infused through an insulin pump.

The pump developed by researchers is a double pump - in addition to insulin, it automatically secretes glucagon, a hormone that taps glucose reserves in the liver, raising blood sugar levels when they get too low, a condition called hypoglycemia.

Dr. Damiano says the system restores, as nearly as possible, the body's delicate metabolic balance.

"We're bringing back to people with Type 1 diabetes not only the proper amount of insulin dosed correctly into the right amount, but also this ability to provide a little bit of glucagon after meals, if the insulin dosing turned out to be a little excessive. And that typically is enough to prevent people from becoming hypoglycemic. So it really prevents you from going low, and that's its main function."

Researchers ran trials of the software for the artificial pancreas with 11 diabetics. The system effectively controlled participants' blood sugar for 27 hours, during which time they ate three high-carbohydrate meals and slept through the night at a hospital.

The artificial pancreas kept glucose levels within the target range for six participants. But the remaining five other patients did not respond as quickly to the insulin infusion and developed low blood sugar because the computer continued to administer medication.

Researchers adjusted their computer algorithm to the slower insulin absorption rate and on a repeat experiment blood glucose was tightly controlled in all of the subjects.

Steven Russell, an assistant in medicine at Massachusetts Hospital in Boston and co-author of the study, said the next step is for researchers to develop a portable system about the size of a cellular telephone.

"The insulin pumps exist, the continuous glucose monitors exist. What's really been missing is the right algorithm to connect the two components. Although we run it on a laptop [computer] so that we can monitor its operation, the algorithm itself doesn't require a lot of computer power and could easily be run from a chip that has the capabilities of one that's already in insulin pumps or in cell phones."

With normal regulatory hurdles, Boston University's Edward Damiano estimates that it could be between five and seven years before an artificial endocrine pancreas is commercially available.

Dr. Damiano says the system is not a cure, but it is the next best thing.

"It's just something that hopefully will tide us over until hopefully a cure can be found," he said. "But if it can't be in the near term, it's a far better solution than what people are doing right now. With all that decision-making on their own, this is basically coming in lieu of that."

Researchers describe their artificial pancreas in this week's issue of the journal Science Translational Medicine.