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The objective of this project is to understand defects in insulin secretion that contribute to abnormal glucose metabolism in patients with diabetes. In particular the effects of signals released from the intestine to stimulate insulin secretion will be tested. Patients with type 2 diabetes will have insulin secretion in response to glucose and intestinal factors before and after insulin treatment to lower their blood glucose. It is expected that the results of this work will provide valuable information for treating diabetic people.
The objective of this project is to understand defects in insulin secretion that contribute to abnormal glucose metabolism in patients with diabetes. Diabetes is a major problem for patients receiving care at VA medical centers among whom 20% are affected. Specifically, this project will seek to determine the mechanism(s) by which the incretin effect is impaired in diabetic patients. The incretin effect refers to the action of GI hormones and neural stimuli to increase insulin secretion after food intake, and accounts for approximately 50% of postprandial insulin secretion in nondiabetic humans. There are several studies indicating that this response is severely impaired in patients with type 2 diabetes. The mechanism(s) by which this occurs has not been explained. There is some evidence to suggest that secretion of the important incretins, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), may be impaired in diabetic individuals. There is also some data to suggest that the beta-cells in persons with diabetes are insensitive to the incretins. The problem with the current state of knowledge in this area is that previous work has involved small numbers of diabetic subjects, and did not directly test mechanisms by which the incretin effect is altered in diabetes.
In this project we will determine the role of hyperglycemia to impair the incretin effect. Type 2 diabetic subjects will have the incretin effect measured before and after intensified diabetes treatment. This study will test the effect of chronic hyperglycemia on incretin mediated insulin secretion. In all studies, the incretin effect will be measured before and after these interventions using studies with a within subjects design. A combined glucose clamp/meal tolerance test protocol will be used to quantify the incretin effect.
These studies will allow the role of incretin secretion, incretin action, and overall metabolic milieu, on postprandial insulin secretion to be defined. The results of these studies will add important new information for understanding abnormal beta-cell function in diabetes. By identifying the sites where the incretin effect is impaired this project will provide the basis for new approaches to treat diabetic patients. This is especially relevant with the recent availability of new medications that target the incretin pathways to lower blood glucose.
The blood samples will be drawn and processed in the GCRC. The samples will be frozen and stored in Building 15, Room 401. Samples will be shipped to the Genome Research Institute by staff trained in IATA shipping procedures.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Arm 1 | Experimental | Intervention: Insulin glargine treatment. The study is designed as a within subjects comparison of insulin secretion in type 2 diabetic patients before and after 2 months of insulin treatment to reduce blood glucose. Insulin secretion will be determined with a hyperglycemic clamp using 20% dextrose, and ingestion of an oral glucose solution (75 g). |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| insulin glargine | Drug | Diabetic subjects will be treated with insulin glargine once daily for 2 months. Subjects will monitor their blood glucose and have their insulin dose adjusted in steps of 4-6 units to achieve a goal of less than or equal to 120 mg/dl for fasting blood glucose. |
| Measure | Description | Time Frame |
|---|---|---|
| ISR in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. | 180 minutes |
| C-peptide Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. | 180 minutes |
| Insulin Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. |
| Measure | Description | Time Frame |
|---|---|---|
| HbA1c Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Type 2 diabetic subjects had HbA1c measured before and after 2 months of basal insulin glargine treatment. | 2 months |
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Inclusion Criteria:
Aim 1:
(non-diabetics)
(diabetics)
Aim 2: Same as above
Aim 3: Diabetic with HgA1c 8.0-9.5
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| David D'Alessio, MD | Cincinnati VA Medical Center | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| VA Medical Center, Cincinnati | Cincinnati | Ohio | 45220 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 24092826 | Result | An Z, Prigeon RL, D'Alessio DA. Improved glycemic control enhances the incretin effect in patients with type 2 diabetes. J Clin Endocrinol Metab. 2013 Dec;98(12):4702-8. doi: 10.1210/jc.2013-1199. Epub 2013 Oct 3. |
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No subjects excluded
Recruited from VAMC from 2010-2012
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| ID | Title | Description |
|---|---|---|
| FG000 | Uncontrolled Type 2 Diabetic Subjects | Eligible subjects will have measures of insulin secretion measured using the OGTT/hyperglycemic clamp technique before and after 2 months of treatment to lower blood glucose. |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Arm 1 | Within subjects comparison; before and after treatment. Beta-cell function measured with OGTT/hyperglycemic clamp |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | ISR in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. | Posted | Mean | Standard Error | pmol/min | 180 minutes |
|
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Arm 1 | Within subjects comparison; before and after treatment. Beta-cell function measured with OGTT/hyperglycemic clamp |
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Two subjects could not complete the initial assessment due to poor IV access. All 15 subjects who completed the initial assessment and were started on insulin completed the study. There were no significant adverse events.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| David D'Alessio, MD, Section head, Endocrinology, Cincinnati VAMC | Cincinnati VAMC | 513-475-6478 | david.d'alessio@va.gov |
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| ID | Term |
|---|---|
| D003920 | Diabetes Mellitus |
| D006943 | Hyperglycemia |
| D007333 | Insulin Resistance |
| ID | Term |
|---|---|
| D044882 | Glucose Metabolism Disorders |
| D008659 | Metabolic Diseases |
| D009750 | Nutritional and Metabolic Diseases |
| D004700 | Endocrine System Diseases |
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| ID | Term |
|---|---|
| D000069036 | Insulin Glargine |
| D049528 | Insulin, Long-Acting |
| ID | Term |
|---|---|
| D061385 | Insulins |
| D010187 | Pancreatic Hormones |
| D036361 | Peptide Hormones |
| D006728 | Hormones |
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|
|
| 180 minutes |
| Participants |
|
| Age, Continuous | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Region of Enrollment | Number | participants |
|
Oral glucose administered to uncontrolled type 2 diabetic subjects. |
| OG001 | IV Glucose | IV glucose administered to uncontrolled type 2 diabetic subjects. |
|
|
| Primary | C-peptide Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. | Posted | Mean | Standard Error | nmol/L | 180 minutes |
|
|
|
| Primary | Insulin Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first. | Posted | Mean | Standard Error | pmol/L | 180 minutes |
|
|
|
| Secondary | HbA1c Before and After 2 Months of Insulin Treatment to Improve Average Glycemia. | Type 2 diabetic subjects had HbA1c measured before and after 2 months of basal insulin glargine treatment. | Posted | Mean | Standard Error | % glycosylated hemoglobin | 2 months |
|
|
|
| 0 |
| 15 |
| 0 |
| 15 |
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| D006946 | Hyperinsulinism |
| D006730 |
| Hormones, Hormone Substitutes, and Hormone Antagonists |
| D010455 | Peptides |
| D000602 | Amino Acids, Peptides, and Proteins |