Bionic pancreas 'could lead to cure for type 1 diabetes'
In a new study published in the New England Journal of Medicine, researchers report the success of a bionic pancreas that can help control blood sugar levels in patients with type 1 diabetes, and claim the device may provide "a bridge to the often-promised but still elusive cure" for the disease.
Every year, more than 30,000 individuals in the US are diagnosed with type 1 diabetes - an autoimmune disease in which the pancreas stops producing insulin, a hormone that enables the body to get energy from food. The condition is believed to occur when the immune system attacks and destroys cells in the pancreas that are responsible for producing insulin.
The novel device, created by researchers from Massachusetts General Hospital (MGU) and Boston University (BU), is made up of a smartphone that is connected to a continuous glucose monitor and two pumps, which deliver doses of insulin or glucagon - a peptide hormone that increases glucose levels in the blood - to the patient every 5 minutes.
The research team, including Dr. Steven Russell of the Diabetes Unit at MGU and Edward Damiano of the Department of Biomedical Engineering at BU, conducted an initial study on the first-generation device in 2010. The study, which tested the device on 27 patients with type 1 diabetes, took place in a controlled hospital inpatient environment. Throughout the study, patients ate prescribed meals and stayed in bed for the most part.
But the researchers have now created a new, wearable version of the device, which Russell says allows participants to "stay in something close to their usual environments, exercise and eat whatever they want."
Adapting the device to a patient's individual needs
The original device, although reporting successful results, presented some challenges for testing outside of a hospital environment.
The bionic pancreas (pictured) is made up of a smartphone that is connected to a continuous glucose monitor and two pumps, which deliver doses of insulin or glucagon to the patient every 5 minutes.
Image credit: Boston University Department of Biomedical Engineering
For example, the team says the device's control system was unable to adapt to the changing requirements of an individual with type 1 diabetes, as well as the different needs of adolescents and adults.
They note that in adolescents, fast growth and hormonal changes mean their insulin requirements are two to three times greater than those of adults who are the same body weight. In addition, they point out that although the insulin doses an adult requires are more predictable, something as simple as catching a cold or a stomach bug can significantly change their insulin needs from days to weeks at a time.
With this in mind, the investigators carried out a number of software improvements so the device can adapt to a patient's individual dosage needs. Furthermore, the team added a smartphone to the mix, allowing the two insulin- and glucagon-delivering pumps to be activated by wireless communication.
The researchers explain that every 5 minutes, the smartphone - an iPhone 4S - receives a blood sugar reading from an attached continuous blood glucose monitor. The smartphone uses this reading to calculate the dose of insulin or glucagon that needs to be delivered to the patient.
The smartphone also consists of an app that requires the patient to enter dietary information before a meal - simply whether they are about to have breakfast, lunch or dinner and whether their carbohydrate intake will be typical, smaller or large than normal. The team says that this is much easier than the complicated calculations patients usually have to do to estimate carbohydrate intake.
Testing the updated device on adults and adolescents
For their study, the team tested the updated device in two separate 5-day clinical trials. Both trials compared the effectiveness of the device against that of the insulin pumps patients normally use to control their blood glucose levels.
The first trial involved 20 participants aged 21 or over with type 1 diabetes. All participants lived at home while managing their diabetes with insulin pumps, but were required to stay within a 3-square-mile area of downtown Boston and sleep in a hotel while using the bionic pancreas, so their blood sugar levels could be continuously monitored by study helpers.
Participants were accompanied by a nurse 24 hours a day while using the bionic pancreas, but were allowed to carry out any activity they chose, such as going to the gym or eating at a restaurant.
The second trial involved 32 participants ages 12-20 with type 1 diabetes who stayed at a summer camp for diabetic adolescents throughout the duration of the study. While using the bionic pancreas, the adolescents had their glucose levels closely monitored through wireless communication by staff at the camp. Participants followed the same activity and meal schedules as other adolescents at the camp during both the bionic pancreas and usual care phases.
The researchers note that in both phases of the adult and adolescent trials, participants received an alert if their blood sugar levels fell below a range that required carbohydrate administration.
Dr. Russell says he was surprised by the results from each trial. He says when patients used the bionic pancreas, not only did average blood glucose levels fall, but the incidence of low blood sugar (hypoglycemia) also reduced.
"The fear of hypoglycemia can limit attempts to bring the average blood sugar into the range that dramatically reduces the risk of long-term complications, so it was remarkable that we saw both of these results at once," he explains.
"Both groups had quite good levels in the usual care arms - averages of 159 mg per deciliter (mg/dl) for both adults and adolescents - but the difference while they were on the bionic pancreas was dramatic, with average blood sugar levels of 133 mg/dl for the adults and 142 ml/dl for adolescents."
For most non-pregnant diabetics, the American Diabetes Association recommended that a blood glucose level should be 154 mg/dl on average, 70-130 mg/dl before a meal and less than 180 mg/dl after a meal.
Commenting on the findings, Damiano says:
"In both of these studies this device far exceeded our expectations in terms of its ability to regulate glucose, prevent hypoglycemia and automatically adapt to the very different needs of adults - some of whom were very insulin-sensitive - and adolescents, who typically need higher insulin doses. There's no current standard-of-care therapy that could match the results we saw."
Device 'could lead to a cure for type 1 diabetes'
Damiano says the device can offer an array of benefits to patients with type 1 diabetes. The most practical benefit, he says, is that patients would not have to think about their diabetes 24/7.
The smartphone part of the bionic pancreas displays patients' blood sugar reading, as provided by the attached glucose monitor every 5 minutes.
Image credit: Boston University Department of Biomedical Engineering.
"Another real problem that would be relieved is the fear - fear of going to bed at night and not knowing if your blood sugar level will drop dangerously low while you sleep," he adds. "Even our study participants, who controlled their blood sugars significantly better than national averages on their usual care, ran high levels overnight but still had significant episodes of hypoglycemia."
He notes that the device will also eliminate a patient's sense of failure when they are unable to get their blood glucose levels to the required range. "But of course you didn't fail; the tools that are available to you failed. The bionic pancreas we are working toward would relieve that sense of failure and provide a bridge to the often-promised but still elusive cure for type 1 diabetes."
The team is now in the process of conducting two follow-up trials on the device. One of these will compare the device's effectiveness over 11 days against that of usual care, and participants will be able to reside in their own home if they are within 1 hour's drive of the study site.
Medical News Today recently reported on a study that was presented at the American Diabetes Association Scientific Sessions in San Francisco, CA, which suggested that periodic fasting may protect against diabetes in individuals who are at high risk of the disease.
Written by Honor Whiteman
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