April 14, 2010 -- Researchers have added a new element to the "artificial pancreas" that may help the 3 million Americans living with type 1 diabetes better control their blood sugar (glucose) levels and stave off diabetes-related complications.
The new findings appear in Science Translational Research.
Research on the development of an artificial pancreas has traditionally focused on delivery of insulin. But the new design introduces another hormone called glucagon to the equation.
People with type 1 diabetes do not produce any insulin, which is needed to regulate blood sugar levels. Glucagon is another hormone that is produced by the cells in the pancreas to help control blood sugar levels. People with diabetes do produce glucagon, but not efficiently. As a result, they are at risk of developing low blood sugar (hypoglycemia) in response to excess insulin.
The artificial pancreas described in the new study comprises a continuous blood sugar monitor and two pumps that communicate with each other via a computer.
"We measure blood glucose on a laptop and have pumps to deliver insulin and glucagon, but there is continuous glucose monitoring, which will send wireless signals to the laptop that wirelessly controls the pumps that give insulin and glucagon," says study researcher Steven J. Russell MD, PhD, an endocrinologist at Massachusetts General Hospital Diabetes Center in Boston. "It adds the capability to give glucagon, and that hasn't been available before and is pretty important."
"It is well known that people with type I diabetes don't make insulin, but they also have a deficiency in making glucagon," Russell tells WebMD.
If researchers get this right, "the benefits will be that people spend a lot less time thinking about and worrying about their diabetes and parents will worry less about their children with diabetes when they are away," he says. "It will improve blood glucose control and reduce risk of developing complications of diabetes."
The new study looked at the two-hormone artificial pancreas system in 11 adults with type 1 diabetes. Researchers monitored participants' blood sugar levels for 26 hours. They found that there was a great variation in insulin levels. As a result, some participants developed low blood sugar. They then tweaked an algorithm to provide a slower insulin absorption and prevent hypoglycemia. It worked.
"The results are very encouraging and suggest that an artificial pancreas using insulin and glucagon in small doses works very well in a broad range of people over 18 with significant variability in insulin absorption rates," says study co-researcher Edward R. Damiano, PhD, an associate professor of biomedical engineering at Boston University."The new system may provide much better glucose control and very little hypoglycemia risk."
Future of the Artificial Pancreas
Careful not to call the artificial pancreas "the holy grail" as it has been called by some, Damiano tells WebMD that "the artificial pancreas is a stop-gap measure to get us through until we find a to a cure for type 1 diabetes or a way to prevent it."
The researchers plan on testing the artificial pancreas on people aged 12 and older for more than 48 hours to see if the results hold up. There will be more testing after that, but if the results pan out, an artificial pancreas could be available within five years. An insulin-only artificial pancreas may well come to market first.
For starters, glucagon has not been previously used in microdoses.
Today, people with type 1 diabetes have a glucagon emergency kit which can be used to reverse severe hypoglycemia. "The new system uses very small doses that are not much more than 1% of a rescue dose," Damiano says. "The levels of glucagon that are delivered are really small and close to normal range for people without diabetes."
"This is super exciting and super important, but will take more time," says Aaron Kowalski, PhD, assistant vice president for glucose control research at the Juvenile Diabetes Research Foundation based in New York City, which funded part of the new research.
"The key here is the glucagon," he says. As it stands, people with diabetes only use insulin and turn to glucagon in an emergency. "It's akin to driving a car with no brakes. The insulin acts as an accelerator, but there is no brake if there is excess insulin. The new system has an accelerator and a brake."