Restored hypoglycemic counterregulation is stable in successful pancreas transplant recipients for up to 19 years after transplantation

Background. Pancreas transplantation has been shown to fully restore glucag on response and partially restore epinephrine response to hypoglycemia duri ng the first few years after transplantation in patients with type 1 diabet es. 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 hypo-glycemic counterregulatio n is maintained over a prolonged period after transplantation, we studied c ounterregulatory responses and symptom recognition in two groups of pancrea s transplant recipients using a stepped hypoglycemic, hyperinsulinemic clam p. Group 1 consisted of 11 successful transplant recipients of 11 to 19 yea rs' 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 earlie r using the same stepped, hypoglycemic clamp technique. Results. Both groups had significant rises in plasma glucagon during the hy poglycemic clamp similar to that seen in short-term recipients and normal c ontrols. Both groups also had significant increases in plasma epinephrine r esponses similar to that seen in short-term transplant recipients but less than that of normal control subjects. The mean symptom scores of group I we re 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 we re not significantly different than that of control subjects. Conclusion. These results indicate that the restoration of hypoglycemic cou nterregulation by pancreas transplantation remains stable in successful pan creas transplant recipients for up to 19 years after transplantation.