Background: Pancreas transplantation has been shown to fully restore glucagon response and partially restore epinephrine response to hypoglycemia during the first few years after transplantation in patients with type 1 diabetes. However, prior studies have not examined hypoglycemic counterregulation in any pancreas transplant recipient of more than 6 years' duration.
Methods: To determine whether restoration of hypoglycemic counterregulation is maintained over a prolonged period after transplantation, we studied counterregulatory responses and symptom recognition in two groups of pancreas transplant recipients using a stepped hypoglycemic, hyperinsulinemic clamp. Group 1 consisted of 11 successful transplant recipients of 11 to 19 years' duration (mean+/-SE, 13.9+/-0.7 years). Group 2A consisted of seven successful pancreas transplant recipients of 5 to 11 years' duration (mean+/-SE, 8.7+/-0.9 years) who had been studied approximately 5 years earlier using the same stepped, hypoglycemic clamp technique.
Results: Both groups had significant rises in plasma glucagon during the hypoglycemic clamp similar to that seen in short-term recipients and normal controls. Both groups also had significant increases in plasma epinephrine responses similar to that seen in short-term transplant recipients but less than that of normal control subjects. The mean symptom scores of group 1 were significantly less than those of the control group at glucose levels of 60 and 50 mg/dL but not at 40 mg/dL. The mean symptom scores of group 2A were not significantly different than that of control subjects.
Conclusion: These results indicate that the restoration of hypoglycemic counterregulation by pancreas transplantation remains stable in successful pancreas transplant recipients for up to 19 years after transplantation.