Recent progress in mechanical artificial pancreas

Strict blood glucose (BG) control is proved to improve the outcome in patients with glucose intolerance both in acute and chronic phases, irrespective of whether the patient has diabetes mellitus. However, strict BG control by conventional methods is so complicated that it cannot be performed easily in normal clinical situations. Furthermore, it is sometimes inadequate. Therefore, a clinically applicable, reliable artificial pancreas (AP) has long been sought after for more than 40 years. Considering the present important situations concerning AP, a survey of recent progress in AP is highly desirable. In this review, recent progress in mechanical AP (MAP) and in MAP-related items is presented. MAP is composed of three major components: a BG control algorithm, a drug administration system, and a glucose sensor. Recent progress in development of these components is presented, followed by descriptions of representative MAPs. Although significant progress in the development of MAP has been made, its use in clinical situations is limited or for research purposes at present. The main limiting factor is the slow progress in the development of glucose sensors. However, more widespread clinical application of the MAP will occur in the near future, considering the number of reliable long-life intravenous glucose sensors under development. Another factor is the worldwide recognition of the importance of BG control in acutely ill patients, in whom the period of strict BG control is usually for several days to a few weeks.