Blood Glucose Control in Type 1 Diabetes With a Bihormonal Bionic Endocrine Pancreas
- Steven J. Russell, MD, PHD1,
- Firas H. El-Khatib, PHD2,
- David M. Nathan, MD1,
- Kendra L. Magyar, MSN, NP1,
- John Jiang, BS2 and
- Edward R. Damiano, PHD2⇓
- 1Diabetes Unit and Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- 2Department of Biomedical Engineering, Boston University, Boston, Massachusetts
- Corresponding author: Edward R. Damiano: .
OBJECTIVE To test whether safe and effective glycemic control could be achieved in type 1 diabetes using a bihormonal bionic endocrine pancreas driven by a continuous glucose monitor in experiments lasting more than two days and including six high-carbohydrate meals and exercise as challenges to glycemic control.
RESEARCH DESIGN AND METHODS Six subjects with type 1 diabetes and no endogenous insulin secretion participated in two 51-h experiments. Blood glucose was managed with a bionic endocrine pancreas controlling subcutaneous delivery of insulin and glucagon with insulin pumps. A partial meal-priming bolus of insulin (0.035 units/kg/meal, then 0.05 units/kg per meal in repeat experiments) was administered at the beginning of each meal (on average 78 ± 12 g of carbohydrates per meal were consumed). Plasma glucose (PG) control was evaluated with a reference quality measurement on venous blood every 15 min.
RESULTS The overall mean PG was 158 mg/dL, with 68% of PG values in the range of 70–180 mg/dL. There were no significant differences in mean PG between larger and smaller meal-priming bolus experiments. Hypoglycemia (PG <70 mg/dL) was rare, with eight incidents during 576 h of closed-loop control (0.7% of total time). During 192 h of nighttime control, mean PG was 123 mg/dL, with 93% of PG values in the range of 70–180 mg/dL and only one episode of mild hypoglycemia (minimum PG 62 mg/dL).
CONCLUSIONS A bihormonal bionic endocrine pancreas achieved excellent glycemic control with minimal hypoglycemia over the course of 2 days of continuous use despite high-carbohydrate meals and exercise. A trial testing a wearable version of the system under free-living conditions is justified.
- Received January 12, 2012.
- Accepted June 12, 2012.
- © 2012 by the American Diabetes Association.
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