Clinical experience with an implanted closed-loop insulin delivery system

AIM: To report the first clinical experience with a prototype of implanted artificial beta-cell. METHODS: The Long-Term Sensor System® project assessed the feasibility of glucose control by the combined implantation of a pump for peritoneal insulin delivery and a central intravenous glucose sensor, connected physically by a subcutaneous lead and functionally by PID algorithms. It was performed in 10 type 1 diabetic patients from 2000 to 2007. RESULTS: No harmful complication related to implants occurred. Insulin delivery was affected by iterative but reversible pump slowdowns due to insulin precipitation. Glucose measurement by the intravenous sensors correlated well with meter values (r = 0.83-0.93, with a mean absolute deviation of 16.5%) for an average duration of 9 months. Uploading of pump electronics by PID algorithms designed for closed-loop insulin delivery allowed in-patient 48 hourtrials. CONCLUSION: Although the concept of a fully implantable artificial beta-cell has been shown as feasible, improvements in the sensor structure to increase its longevity and decrease sensor delay that affected closed-loop control at meal-times are expected.