Pancreatic islet transplantation improves glucose counterregulation and stabilizes glycemic control in patients with type 1 diabetes mellitus prone to severe hypoglycemia even if insulin independence is not achieved. However, the extent and underlying metabolic pathways of this improvement are unknown. Investigators therefore compare systemic glucose turnover including lactate gluconeogenesis and muscle glucose utilization, between insulin-requiring islet transplant recipients, matched type 1 diabetic subjects who did not receive islet transplantation, and matched healthy non-diabetic subjects.
Subjects (n=12 each group) undergo a hypoglycemic and a euglycemic hyperinsulinemic clamp in a randomized fashion. Systemic and skeletal muscle glucose and lactate kinetics are assessed using a combination of isotopic and forearm balance techniques.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
36
Each study participant will be subjected to a continuous infusion of insulin at a rate of 0.8 mU·kg-1·min-1 to induce hypoglycemia (blood glucose 2.8-3 mmol/l) for 30 minutes. At least two weeks later an identical insulin infusion will be administered and euglycemia (blood glucose 5 mmol/l) will be targeted. The order of these interventions will be subject to randomization.
Justus Liebig University
Giessen, Hessia, Germany
Whole body glucose counterregulation
Whole body glucose counterregulation is the difference in glucose infusion rates required to maintain the glycemic goal between the hypoglycemic and euglycemic clamp. Clamps were performed at two time points at least two weeks apart. Participants will be followed for the duration of 6-8 weeks to perform the hypoglycemic and euglycemic clamp tests.
Time frame: 6-8 weeks
Systemic glucose release
Systemic glucose release is the amount of glucose released primarily from the liver into the blood compartment during a given time. The unit of measure is μmol/kg/min. Participants will be followed for the duration of 6-8 weeks to perform the hypoglycemic and euglycemic clamp tests that will yield this parameter.
Time frame: 6-8 weeks
Skeletal muscle glucose disposal
Participants will be followed for the duration of 6-8 weeks to perform the euglycemic and hypoglycemic clamp tests. The unit of measure of this parameters is μmol/kg/min.
Time frame: 6-8 weeks
Gluconeogenesis from lactate
This parameter is determined by labelled lactate infused into the proband. The rate of the de novo synthesis of glucose (gluconeogenesis) is determined by the degree of incorporation of the lactate label into glucose molecules. The unit of measure of this parameter is μmol/kg/min.
Time frame: 6-8 weeks
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