The system combines a blood glucose monitor and insulin pump technology with software that directs administration of insulin and the blood-sugar-raising hormone glucagon. The first clinical trial of the system confirmed the feasibility of an approach utilizing doses of both hormones. In their report, the researchers also found unexpectedly large differences in insulin absorption rates between study participants, differences they were able to account for by adjustments to the system.
"This is the first study to test an artificial pancreas using both insulin and glucagon in people with type 1 diabetes. It showed that, by delivering both hormones in response to frequent blood sugar tests, it is possible to control blood sugar levels without hypoglycemia, even after high-carbohydrate meals," says Steven Russell, who co-led the research team with Edward Damiano. All previous reported studies of artificial pancreas systems have included episodes of hypoglycemia, but this is the first study to confirm and address the cause of that hypoglycemia, the researchers say.
The researchers developed a system that both accounts for the rate of insulin absorption and also incorporates glucagon, a hormone naturally released by the pancreas to raise blood sugar levels. While the alpha cells of the pancreas that produce glucagon are not destroyed in people with type 1 diabetes, the cells no longer release glucagon in response to low blood sugar.
"Large doses of glucagon are used as a rescue drug for people with severely low blood sugar," explains Damiano. "Our system is designed to counteract moderate drops in blood sugar with minute doses of glucagon spread out throughout the day, just as the body does in people without diabetes." In 2007 the system was tested in diabetic pigs, which led to FDA approval of the human trial.
MEDICA.de; Source: Boston University