β-cell–mimetic designer cells provide closed-loop glycemic control

Engineering cells to regulate glucose Diabetes mellitus affects hundreds of millions of people worldwide. Blood glucose levels are chronically deregulated in diabetics, and this can lead to many serious disorders, including cardiovascular disease and renal failure. Xie et al. engineered a synthetic circuit into human cells that can sense the glucose concentration and respond to correct deregulation. Implants containing designer cells improved glucose regulation in diabetic mice. Science , this issue p. 1296