An artificial pancreas may revolutionize the treatment of diabetes, and it may only take a few years.
For millions of people with diabetes around the world, life is filled with finger pricks, injections, and spikes and drops in blood sugar levels. For people who want to regulate their blood sugar levels automatically, an artificial pancreas could change all that.
The artificial pancreas is made up of 3 parts
“The artificial pancreas will revolutionize the treatment of diabetes,” said Eric Renard, PhD, professor of endocrinology, diabetes and metabolism at the Montpellier School of Medicine in Montpellier, France. “It could prevent complications of diabetes, including blindness, kidney failure, amputations, heart disease and even death.”
Renard, who led the first clinical trial of the device, said, “Because people will no longer need to constantly needle and thus monitor their health, the quality of life will be greatly improved.”
He explained that the artificial pancreas is designed to help people with type 1 diabetes keep their blood sugar levels in a normal range, which is essential for preventing diabetes complications.
Jeffrey I. Joseph, PhD, director of the Center for the Artificial Pancreas at Thomas Jefferson University in Philadelphia, said the artificial organ has 3 parts that must work in perfect synchronization: the 3 parts are sensors that continuously monitor blood or tissue sugar levels, an insulin infusion pump, and a computer algorithm that controls insulin delivery per minute based on blood glucose measurements. The sensor passes the information to the insulin infusion pump, and then the pump dispenses the right amount of insulin.
“We’re moving toward that goal step by step,” Joseph said, with researchers around the world testing components of the system individually and together.
Insulin pumps ease patients’ lives
The best-developed device is the insulin pump, which can be worn on a belt or fully implanted in the body. External pumps are already used by thousands of people with diabetes worldwide, and implantable pumps are approved in Europe and in clinical trials in the United States, both of which can be used in an artificial pancreas.
Reynolds said the development of implantable pumps is a big step forward, and studies have shown big benefits in controlling blood sugar levels and improving quality of life with multiple daily injections of insulin.
The puck-sized device, made by Medtronic MiniMed in Northridge, California, is implanted under the skin in the abdomen, and the device delivers insulin to the body “just like a real pancreas,” he said.
Lori Hahn, a 41-year-old Californian who has had diabetes for more than a decade, said the implantable pump has changed her life.
“Before the implantable pump, my life was a roller coaster of blood sugars and emotions,” said Hahn, who is participating in a U.S. clinical trial. “I felt out of control and had to spend a lot of time trying to control my blood sugar levels. With the implantable pump, I can forget I’m diabetic,” said Hahn, a full-time wife and mother of three active children.
The pump uses a special formula of insulin that is refilled every 2 to 3 months. Insulin is delivered in small doses throughout the day, similar to the pancreas. It is also programmed to deliver more insulin at mealtimes. Before a meal or snack, press a button on a pager-sized personal pump communicator to cause the pump to dispense a dose of insulin.
Smart system to manage the amount of insulin needed
Other research has focused on improving the transfer of information between the glucose sensor and the external insulin pump. According to Joseph, the U.S. Food and Drug Administration (FDA) approved one of the first smart systems that allows information transfer between the two systems via a wireless connection, which is a major milestone.
He said such a system would require a lot of measurement work in insulin dosing.
Traditionally, patients have had to prick their finger and place a blood drop on a test strip to get a blood glucose reading to estimate how many grams of carbohydrates they plan to eat and to calculate how much insulin they need. This system has a large margin for error, and miscalculations can lead to dangerously high or low blood glucose levels.
With the newly approved Paradigm system, which combines a Medtronic MiniMed insulin pump and a glucose monitor from BD (Becton Dickinson), patients still measure their blood glucose levels by pricking their finger, but the pager-sized glucose monitor sends the information directly to the insulin pump. The insulin pump then calculates the amount of insulin needed for current blood glucose. Calculating the required dose through the pump prevents the errors that sometimes result from entering this data manually, he said.
Joseph said, “It’s up to the patient to decide if the recommended dose is correct and to push the button to deliver the recommended dose.” “It’s not an artificial pancreas, because it’s not fully automated. But it’s a big advance in convenience and has the potential to improve glycemic control in a clinical setting.”
Glucose sensor measures blood glucose levels
Joseph said there are about two dozen companies and academic labs working on glucose sensors. Some are blood glucose sensors and some are tissue fluid glucose sensors; some are placed under the skin by the patient and some are implanted in the body over time.
He said that while glucose sensors have improved significantly in the last few years, they remain a limiting factor in making an artificial pancreas.
Steve Lane, PhD, acting project leader for the medical technology program at the U.S. Department of Energy’s Lawrence Livermore National Laboratory, agreed.
Lane said, “It is almost certain that the goal of producing an artificial pancreas will be achieved.” Lane’s department worked with MiniMed to develop a prototype of the artificial pancreas. “But there are still some hurdles to overcome, and the main one is glucose sensing. To date, no one has developed a very safe way to sense glucose.”
Animas is developing an implantable optical glucose sensor that uses infrared optics to accurately measure blood glucose levels in the bloodstream in animal and preliminary human studies.
“The miniature sensor head is placed around a blood vessel and the light source is focused through the blood to the detector,” Joseph said. “The absorption of light at specific infrared wavelengths determines the concentration of sugar in the blood.”
Further developments are MiniMed’s short- and long-term implantable glucose sensors, designed to continuously measure sugar levels in tissue fluid or blood.
First clinically tested artificial pancreas
In France, Renard led the first clinical trial of an artificial pancreas, combining MiniMed’s long-term glucose sensor with its implantable insulin pump in a fully automated system.
In a small surgical procedure, the implantable sensor is inserted into a jugular vein leading to the heart. The sensor is connected to the implantable insulin pump via a subcutaneous wire: as blood glucose levels fluctuate, the sensor transmits a signal to the insulin pump to indicate the dose of insulin to be delivered by the pump.
“The patient doesn’t have to do anything,” Renard said. “All of this is automated. Even when eating high carbohydrates, the sensor sends the appropriate signal to get the pump to deliver more insulin.”
Reynard said data from the first 5 patients who used the device for at least 6 months showed that the sensor accurately measured glucose levels in 95% of cases compared to values obtained through finger pricks.
He said, “Our goal is to get to 90% accuracy, so this is very accurate.”
More importantly, patients who used an insulin pump with the sensor attached maintained their blood glucose levels in the normal range more than 50% of the time, whereas patients who used an implantable pump to regulate insulin delivery via finger prick measurements maintained their blood glucose levels in the normal range only about 25% of the time.
In addition, Renard said, the risk of a sudden drop in blood sugar to dangerously low levels (called hypoglycemia) – which can occur whenever there is an overdose of insulin delivery – drops to less than 5%.
One of the next steps, he said, is to make the sensors more durable, requiring replacement only every two or three years. While the average implantable insulin pump is used for eight years before it is replaced, the sensors fail after an average of nine months, he said.
However, Renard believes this hurdle is easy to overcome. “We just have to use a different material and make it more robust,” he said.
But Joseph said this could present a huge challenge: “Years of research have shown that sensors tend to fail within months rather than years because of the harsh environment of the body.”
The mathematical procedures for calculating insulin delivery at different times of the day also need to be refined, Renard said. “Right now, an insulin pump can allow a diabetic to maintain normal blood sugar levels for half a day, just like a non-diabetic. But that also means he can’t control his blood sugar levels for the other half of the day, which is a little too high a percentage.”
But he added that the problem is easy to fix. “The main problem is to have accurate sensors, which we have today. We should have sensors that work longer and run better, and after that, it will be ready for clinical use.”
Joseph agreed. He said, “They’ve demonstrated the feasibility of signaling between the glucose sensor and the insulin pump, and the insulin pump can automatically deliver insulin, which is the artificial pancreas. Does that make it perfect? Of course not. But we’re getting closer to perfection.”