An artificial pancreas system that closely mimics the body’s blood sugar control mechanism was able to maintain near-normal glucose levels without causing hypoglycemia in a small group of patients.
The system, combining a blood glucose monitor and insulin pump technology with software that directs administration of insulin and the blood-sugar-raising hormone glucagon, was developed at Boston University (BU).
The first clinical trial of the system was conducted at Massachusetts General Hospital (MGH) and confirmed the feasibility of an approach utilizing doses of both hormones. In their report, appearing in Science Translational Medicine, 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, MD, PhD, of the MGH Diabetes Unit, who co-led the research team with Edward Damiano, PhD, of the BU Department of Biomedical Engineering.
In type 1 diabetes, the insulin-producing beta cells of the pancreas are destroyed by the immune system, requiring insulin treatment to regulate blood sugar levels. Intensive glucose control involving frequent blood sugar testing and insulin administration can delay or prevent long-term complications ? such as retinal damage, kidney failure, or cardiovascular disease ? but is extremely demanding and difficult to maintain. Continuous glucose monitors and insulin pumps can help, but patients remain at risk for hypoglycemia, a potentially life-threatening drop in blood sugar caused by too much insulin.
Because any administration of insulin, even by an artificial pancreas system, has been associated with the risk of hypoglycemia, BU investigators Damiano and lead author Firas El-Khatib, PhD, 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 Damiano’s team tested the system in diabetic pigs, which led to FDA approval of the human trial.
Source: Boston University, USA