Cystic Fibrosis, Cystic Fibrosis Related Diabetes
Conditions
Brief summary
This project is designed to begin to characterize the abnormalities of glucagon secretion in subjects with cystic fibrosis related diabetes along the spectrum of glucose tolerance. Cystic fibrosis patients with normal glucose tolerance as well as cystic fibrosis related diabetes as well as control subjects will undergo an oral glucose tolerance test, mixed meal tolerance test, and one step hypoglycemic clamp. Cystic fibrosis patients will then return 12 months later to undergo repeat mixed meal tolerance test and hypoglycemic clamp test.
Detailed description
This project is designed to begin to characterize the abnormalities of glucagon secretion in subjects with cystic fibrosis related diabetes along the spectrum of glucose tolerance. This will be a descriptive, cross-sectional and longitudinal cohort study in a sample of children and young adults with CF and a continuum of glucose tolerance compared to healthy age-matched controls. Cystic fibrosis patients with normal glucose tolerance as well as cystic fibrosis related diabetes as well as control subjects will be admitted to the research unit on three separate occasions to undergo an oral glucose tolerance test, mixed meal tolerance test, and one step hypoglycemic clamp. Cystic fibrosis patients will then return 12 months later to undergo repeat mixed meal tolerance test and hypoglycemic clamp test.
Interventions
OTHEROral Glucose Tolerance Test
Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling. Patients will drink 1.75 gm/kg glucose (Glucola) to a maximum of 75 gm. Venous samples for glucose and c-peptide will be drawn from the IV at 0, 30, 60, 90 and 120 minutes. Subjects will be instructed to eat at least 75 gm carbohydrates daily in the week prior to this test.
Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling. Subjects will consume 6 kcal/kg (6 ml/kg) Boost High Protein Nutritional Energy Drink (Mead-Johnson) over five minutes to a maximum of 360 ml. Venous samples for glucose, glucagon, GLP-1, GIP, and c-peptide will be drawn at -10, 0, 15, 30, 60, 90, 120, 150, 180, 210, and 240 minutes.
OTHERHypoglycemic Clamp
All subjects with CF and adult (but not pediatric) controls will undergo one-step hypoglycemic clamp. Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling and a second IV for infusion of insulin and dextrose.
Sponsors
Yale University
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
12 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Diagnosis of CF by clinical or genetic determination * Normal glucose tolerance or CFRD * Subjects routinely taking systemic or inhaled glucocorticoids on stable regimen are eligible
Exclusion criteria
* Subjects with active pulmonary infection requiring supplemental doses of corticosteroids * Use of any oral diabetes medications * Subjects who are pregnant/lactating * Subjects with poor compliance with pancreatic enzyme replacement therapy Control Subjects: Approximately 10 control subjects who are matched for age, gender, are expected to be enrolled in the study. Non-CF subjects must be \>12 years old, in good health and not taking any medications or have any medical problems the doctor feels would prevent the subject from completing the study and have BMI between 15-85% for age and gender. Control subjects whose fasting blood glucose is found to be \>110 mg/dL will not be continued in the study.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Glucagon levels | baseline | Glucagon levels in response to to a mixed meal stimulus |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Epinephrine levels | baseline | Epinephrine and norepinephrine levels during hypoglycemic clamp |
| Norepinephrine levels | baseline | norepinephrine levels during hypoglycemic clamp |
| C-peptide levels | baseline | C-peptide levels during oral glucose tolerance test and mixed meal tolerance test |
| GLP-1 and GIP levels | Baseline | GLP-1 and GIP levels in response to mixed meal stimulus |
| Glucagon levels | 12 months | Glucagon levels in response to to a mixed meal stimulus and difference from baseline |
| Hypoglycemia unawareness scores | Baseline | Hypoglycemia unawareness scores in subjects during hypoglycemic clamps as measured by the Clarke Hypoglycemia Awareness survey |
Countries
United States
Outcome results
None listed