Combining Technology with Treatment

Type 1 diabetes mellitus (T1DM) is characterized by the destruction of the insulin-producing b-cells in the pancreas. Exogenous insulin administration is therefore required to regulate the blood glucose concentration. The goal of diabetes management is to maintain homeostasis and blood glucose near normal levels (80–140 mg/dL) and thus to avoid immediate life-threatening situations, such as severe hypoglycemia and ketoacidosis, and long-term complications, such as cardiovascular disease, nephropathy, neuropathy, and retinopathy. Treatment of T1DM requires either multiple daily insulin injections or continuous subcutaneous (SC) insulin infusion (CSII) delivered via an insulin infusion pump. Both treatment modes necessitate frequent blood glucose measurements (eight to ten times/day, including fasting, pre- and postprandial, before bedtime, and in the middle of the night) to determine the daily insulin requirements for maintaining near-normal blood glucose levels [1]–[3]. With the advent of continuous glucose sensing, which reports interstitial glucose concentrations (that reflect the blood glucose) approximately every minute, and the development of hardware and algorithms to communicate with and control insulin pumps, the vision of closed-loop control of blood glucose is approaching a reality. In individuals without diabetes, blood glucose is controlled by various neural and hormonal inputs from the brain, gut, liver, and pancreas that respond to various situations such as meals, stress, and exercise. A closed-loop system for