Goal Is Automated Monitoring of Blood Sugar, Delivery of Insulin
By Charlene Laino
WebMD Health News
Reviewed by Louise Chang, MD
June 12, 2012 (Philadelphia) -- Efforts to make an artificial pancreas for people with type 1 diabetes have taken another step forward, with two new studies showing progress toward that goal.
Both studies, presented here at the American Diabetes Association's annual meeting, were small, and more work is needed before an artificial pancreas is ready. For more than three decades, researchers have been trying to develop an artificial pancreas.
But as is often the case, progress in science is measured in baby steps, not leaps. So while preliminary, the studies presented offer renewed hope that an artificial pancreas could become a reality within five to 10 years, experts tell WebMD.
Goal: Artificial Pancreas
Though its name may conjure up images of a manmade organ being grown in a sterile "CSI"-type lab, the artificial pancreas is actually an automated system consisting of a continuous glucose monitor, an insulin infusion pump, and a glucose meter for calibrating the monitor.
The goal is to develop an implantable system that mimics a real pancreas. That's the organ that produces insulin, the hormone that regulates blood sugar levels. In type 1 diabetes, the body's immune system attacks insulin-producing cells in the pancreas.
An artificial pancreas would monitor blood sugar levels, sense when the body needs insulin, calculate the dose needed, and deliver it without a person even being aware of what's happening. It's needed because only about two-thirds of people with diabetes keep their blood sugar at recommended levels throughout the day, says Henry Anhalt, MD, chief medical officer at Animas, which is developing one of the systems.
People with type 1 diabetes give themselves insulin injections or use a pump that delivers insulin via a tiny catheter inserted under the skin. Either way, they have to estimate how much insulin they'll need based on their blood sugar, how much they think they will eat, and how much activity they will be doing.
If they miscalculate, they are at risk for dangerously low blood sugar (hypoglycemia) as well as dangerously high blood sugar (hyperglycemia). In the long run, uncontrolled diabetes can lead to complications such as eye damage, kidney failure, and heart disease.
"The artificial pancreas is a wonderful concept and we have the science and technology to get there, but it has to be perfect. The studies presented at this year's meeting are small steps toward that goal," says American Diabetes Association president Vivian Fonseca, MD, of Tulane University in New Orleans.
"We have to see how the devices work in real life as opposed to artificial research settings," says Fonseca, who was not involved with the work.
There are probably about a dozen in various stages of development, according to Gary Steil, PhD, of Harvard Medical School.
Last week, Medtronic Inc. filed an application with the FDA seeking approval of its device that shuts off insulin temporarily if a person's blood sugar levels fall too low. The device is already approved in 50 countries.
Steil's team studied 10 children aged 2-6 with type 1 diabetes. At night, a computer-controlled system kept their blood sugar in the target range for more than five hours, on average.
In contrast, the kids spent only about three hours in the recommended blood sugar level range when a conventional insulin pump was used.
With a conventional pump, parents have to decide how much insulin to give based on their child's blood sugar level and how much they think the child will eat at each meal and at other times throughout the day.
"With kids' unpredictable eating habits, it's a real guessing game," says study head Andrew Dauber, MD, also of Harvard. Dips in blood sugar at night, during sleep, are one of the greatest risks faced by children as well and adults with type 1 diabetes, he says. The episodes can cause seizures and even sudden death.
Because they fear blood sugar dipping, parents may miscalculate the dosage and give their kids too little insulin, he tells WebMD. That can result in abnormally high blood sugar levels -- which over time, leads to all the complications of diabetes, Dauber says.
In the new study, children with type 1 diabetes were hooked to a glucose monitor. The results were entered into a computer, and a program calculated how much insulin was needed. "We did it manually for safety reasons," Dauber says. But the next version of the system will be automated.
The kids were much less likely to have episodes of abnormally high blood sugar at night when they used the closed-loop device than when their parents pumped their insulin. "Every parent told us they had the best night of sleep in years [when the artificial pancreas was used] because they didn't have to worry about hypoglycemia," Dauber tells WebMD.
Another system, called a Hypoglycemia-Hyperglycemia Minimizer, is being developed by Animas Corp. in partnership with the Juvenile Diabetes Research Foundation. In a new study of 13 adults with type 1 diabetes, the system was able to predict rises and falls in blood glucose and correspondingly increase and decrease the insulin dose safely over a 24-hour period.
"The cornerstone of the system is an algorithm that predicts where patients' blood sugar levels are going to go in advance of when they get there and change insulin [dose] accordingly," Anhalt says.
The system is the first to predict, rather than react to, blood sugar levels, he tells WebMD. A larger study is being planned.
These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
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