The long-term benefits of islet transplantation in type 1 diabetes

The authors aimed to determine the benefit of islet transplantation in controlling glucose levels and counterregulation in patients with type 1 diabetes.

The authors concluded that islet transplantation can lead to long-term improvements in glucose levels and low blood sugar symptom recognition that contributes to stable blood sugar levels following transplantation.

The pancreas contains small cells that are used to produce the hormone insulin. Insulin controls blood sugar levels, and is inadequately produced in patients with diabetes. Patients with diabetes may experience episodes of low or high blood sugar levels. 

Very low blood glucose levels (hypoglycemia) can be very dangerous. Glucose counterregulation is the sum of processes that protect against development of hypoglycemia and restore normal glucose levels if this should occur. It is very important that patients with diabetes are capable of recognizing low blood sugar symptoms. However, some patients may have hypoglycemia unawareness. This means that they will not feel the warning symptoms others might feel, such as shaking or sweating. 

Islet transplantation involves taking cells from a donor pancreas and transplanting them into a specific patient. This is an experimental treatment for type 1 diabetes. The transplanted cells have been shown to improve insulin production. It is thought that they may also restore a patient's ability to recognize symptoms during low blood sugar events. 

The aim of this study was to determine the long-term benefit of islet transplantation in improving blood sugar control in patients with type 1 diabetes.

10 patients were used in this study. HbA1c levels (a measurement of average blood sugar levels over the past three months), which were elevated before transplantation, were decreased to non-diabetic levels after transplantation. These levels remained at less than 6.5% for the duration of the 24 month follow-up.

7 patients were insulin-independent following one transplantation and 3 patients were insulin-independent following two transplantations. Following transplantation, no patient experienced any clinically significant hypoglycemia events.

Continuous glucose monitoring (CGM – a small, wearable device that continuously tracks blood sugar levels) demonstrated improvements in glucose levels over a 24 month period. In patients who experienced insulin-induced hypoglycemia, glucagon (a hormone that raises blood sugar) secretion was nearly restored after 6 to 18 months (but remained lower than normal). Adrenaline levels (a hormone released during hypoglycemia) were improved at 6 months and normalized at 18 months. Glucose production and symptoms were normalized at 6 and 18 months following transplantation.

The authors concluded that intrahepatic islet transplantation can lead to long-term improvements in glucose levels and low blood sugar symptom recognition that contributes to stable blood sugar levels.