Use of the artificial B-cell (Biostator) in improving insulin therapy in unstable insulin-dependent diabetes

The present study was designed to improve the conventional subcutaneous insulin treatment of labile insulin-dependent diabetic patients by means of the artificial B-cell (Biostator) during a combination of conventional treatment and a glucose-controlled insulin infusion. Eleven patients with no residual B-cell function and poor metabolic control were studied. All patients were treated as effectively as possible by conventional methods using a combination of regular and intermediate insulin under clinical conditions. In order to determine the inadequacy of previous insulin treatment, all patients were connected to the Biostator, and the profile of daily physical activity was simulated using a bicycle ergometer. Metabolic control was compared during a 6-day period before and after a 30-50-h connection to the artificial B-cell. Using a preselected blood glucose level of 80 mg/dl (4.44 mmol/L), the additional insulin requirement amounted to 45.5 +/- 11.1 U/24 h (N = 6). The day after connection to the artificial B-cell, the patients received a new insulin regimen according to the additional insulin delivery determined by the Biostator. No better metabolic control was achieved and frequent hypoglycemic episodes occurred in this group. Another group (N = 5) was therefore studied at a preselected blood glucose level of 130 mg/dl (7.22 mmol/L). The mean additional insulin delivery by the Biostator was lower (17.2 +/- 2.1 U/24 h; P less than 0.05) and all patients were significantly better equilibrated after the new insulin regimen derived from data given by the Biostator. The ratio of short-acting to intermediate-acting insulin was 3:1; 40% of the total dosage was given in the morning. This study demonstrates that using the Biostator in addition to subcutaneous insulin allows determination of the amount of additional regular insulin that should be administered to improve glycemic control in labile diabetes.