What is type 1 diabetes?

Type 1 diabetes is an autoimmune condition in which the immune system attacks and destroys the insulin-producing beta cells in the pancreas. Without enough insulin, blood glucose rises, and the body cannot use glucose for energy properly. Without external insulin, the condition is fatal.

Why it is different from type 2 diabetes. Type 2 diabetes mostly involves insulin resistance (the body's tissues respond less well to insulin) and often progressive failure of beta cells over years. Type 1 diabetes involves nearly complete loss of beta-cell function over a shorter time. The causes, biology, and (until recently) treatment options have been quite different.

The traditional therapy. Since 1922, type 1 diabetes treatment has centred on replacing the missing insulin. Modern insulin therapy uses a combination of short-acting insulin (taken with meals) and long-acting insulin (taken once or twice daily) to mimic the natural pattern. Continuous glucose monitoring devices show glucose levels every few minutes, and insulin pumps deliver precise doses.

The modern delivery option. Automated insulin delivery (AID) systems combine a continuous glucose monitor, an insulin pump, and an algorithm that adjusts insulin delivery automatically based on glucose readings. AID systems substantially improve time-in-range glucose control and reduce the burden of constant decision-making.

The disease-modifying option. Teplizumab is an immune-modulating medicine that, given as a 14-day course in people who have been identified as being in early stage 2 type 1 diabetes (autoantibodies present and glucose levels starting to rise but not yet at full diabetes), can delay the onset of full clinical type 1 diabetes by an average of two to three years. This is the first treatment that addresses the underlying autoimmune attack rather than just replacing insulin.

The beta-cell replacement frontier. Stem-cell-derived beta-cell replacement therapy is in late-stage trials. The goal is to provide a renewable source of insulin-producing cells that could allow people with type 1 diabetes to discontinue or substantially reduce insulin therapy. Several programs are reading out, with encapsulation approaches that might avoid the need for ongoing immunosuppression in active development.

What to expect. Type 1 diabetes is currently a lifelong condition managed through insulin, monitoring, lifestyle, and increasingly through automated delivery systems. The combination of disease-modifying therapy in early disease and beta-cell replacement in established disease may reshape the long-term outlook over the next decade.