The pancreas of an individual with type 1 diabetes does not produce the hormone insulin, which is essential to allow body tissues to take up and use glucose from the blood. Before the discovery of insulin in the 1920s, such people had little chance of living a normal lifespan. And even with insulin injections, it is difficult to keep blood sugar within normal boundaries. Too little insulin, or insulin injected at the wrong time, could mean high blood sugar and later complications such as blindness and kidney failure. Conversely, too much insulin could mean hypoglycemia (low blood sugar), which in turn can lead to passing out a real threat if a person is driving, for example.
Technology has been coming to the rescue first with genetically engineered human insulin, then with insulins that act for varying periods of time, and also with the insulin pump a device that allows a user to program doses of insulin. But this pump still requires action by the user and evaluation of changing circumstances. For example, a person might require less insulin after a bout of exercise than she would if sitting and reading or doing computer work.
Now a new type of pump has made its debut. It s a pump that includes a glucose monitor that can automatically determine how much insulin or glucagon a person needs, and supply it without the user s intervention (glucagon is another hormone produced by the pancreas that raises blood sugar, thus counteracting the effect of too much insulin). The device was tested recently and the results were reported in the New England Journal of Medicine.
Dr. Steven J. Russell from Massachusetts General Hospital and Harvard Medical School and colleagues enlisted 20 adults (approximately 40 years old) and 32 adolescents (averaging 16 years old) to participate in the study. All had been diagnosed with type 1 diabetes at least one year prior to the study, and all had been using the standard insulin pump.
In random order, the participants received therapy with the bionic pancreas for five days, and therapy with their own pumps for 5 days.
Adult patients lived at home and carried out their usual activities when they were using their own pumps. When using the bionic pumps, they were also free to move about, and were accompanied by study staff members. They stayed in hotels at night and had their blood glucose levels measured every half hour.
The adolescent participants lived at a diabetes camp during the study.
The main outcomes were the mean plasma glucose levels, and the percent of time the person had a low glucose level. The researchers found that, for the adults, the mean glucose level was significantly lower when they used the bionic pump compared to their own insulin pumps (138 VS 159 mg/deciliter). In addition, the percent of time with low blood glucose was also significantly lower with the bionic pump (4 percent VS 7 percent).
Similarly, among the adolescents, the blood glucose levels were significantly lower with the bionic pump (138 VS 137 mg/deciliter). However, the percent of time with low blood glucose was similar on both pumps.
The authors summarized their results: the use of the bihormonal bionic pancreas in our two short-term studies resulted in better glycemic control than is possible with the current standard of care.
ACSH s Dr. Ruth Kava thinks that if this study can be reliably replicated, this type of pump will swiftly become the standard of care for people with type 1 diabetes. She added The holy grail for diabetes researchers has been developing an artificial pancreas that can control blood glucose as well as a real pancreas. We re not there quite yet, but this new bionic pump suggests we re well on the way.
