Insulin Receptor Substrate 1 (IRS-1) Regulation in Insulin Resistance

This study has been completed.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Lawrence Mandarino, Mayo Clinic
ClinicalTrials.gov Identifier:
NCT01240252
First received: September 29, 2010
Last updated: June 3, 2013
Last verified: June 2013
  Purpose

The study is being conducted to find out why too much fat in your blood stream may cause insulin resistance in your muscles. Insulin is the hormone, produced normally by your body, which causes your blood sugar to return to normal after you eat.


Condition Intervention Phase
Type 2 Diabetes Mellitus
Drug: Human insulin
Phase 1

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Molecular Regulation of Muscle Glucose Metabolism in Man, Protocol 4

Resource links provided by NLM:


Further study details as provided by Mayo Clinic:

Primary Outcome Measures:
  • Proportion of insulin resistant patients with elevated serine/threonine phosphorylation of IRS-1 in muscle. [ Time Frame: one month from date of volunteer study ] [ Designated as safety issue: No ]
    IRS-1 will be immunoprecipitated from percutaneous muscle biopsies, resolved by gel electrophoresis, digested with trypsin, and analyzed by high-performance liquid chromatography nanospray tandem mass spectrometry (MS/MS) analysis


Secondary Outcome Measures:
  • Quantitative assay of the ability of insulin to clear glucose from the blood in insulin resistant patients. [ Time Frame: one month from date if volunteer study ] [ Designated as safety issue: No ]
    The glucose clamp gives a quantitative measure, in mass per unit body weight per minute, of the ability of insulin to cause glucose to disappear from the blood


Enrollment: 14
Study Start Date: March 2012
Study Completion Date: July 2012
Primary Completion Date: July 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Type 2 Diabetes Mellitus Subjects
Two hours after the start of deuterated glucose, subjects will receive human insulin (U100 Humulin) at a rate of 80 mU/m^2 surface area per minute one time over 4 hours.
Drug: Human insulin
U100 Humulin at a rate of 80 mU/m^2 surface area per minute one time over 4 hours
Other Name: Humulin
Experimental: Overweight or Obese Subjects with Normal Glucose Tolerance
Two hours after the start of deuterated glucose, subjects will receive human insulin (U100 Humulin) at a rate of 80 mU/m^2 surface area per minute one time over 4 hours.
Drug: Human insulin
U100 Humulin at a rate of 80 mU/m^2 surface area per minute one time over 4 hours
Other Name: Humulin
Placebo Comparator: Non-Obese Control Subjects
Two hours after the start of deuterated glucose, subjects will receive human insulin (U100 Humulin) at a rate of 80 mU/m^2 surface area per minute one time over 4 hours.
Drug: Human insulin
U100 Humulin at a rate of 80 mU/m^2 surface area per minute one time over 4 hours
Other Name: Humulin

Detailed Description:

Insulin resistance in skeletal muscle is an early event in the pathogenesis of type 2 diabetes, obesity, and other conditions associated with the Metabolic Syndrome. The aim of this study is to determine the extent to which the inflammatory response to lipids is present in naturally occurring insulin resistance. We will test the hypothesis that skeletal muscle from insulin resistant volunteers is characterized by:

  1. Increased concentrations of circulating proinflammatory cytokines without changes in cytokine expression in muscle.
  2. Increased inflammatory response in muscle.
  3. Increased infiltration of inflammatory cells into skeletal muscle.
  4. Changes in expression of proteasome genes.

Forty five subjects will be studied in total. Three groups will be studied. One group will consist of 15 patients with type 2 diabetes mellitus The second group will consist of 15 age, gender, and body composition matched overweight or obese subjects (27 < BMI <36) with normal glucose tolerance. The third group will consist of 15 age and gender matched nonobese control subjects (BMI < 27).

There will be two visits in the study, a screening visit and the study visit. At visit 2 the subject will report to the study site having fasted since the night before, discuss the study and provide written consent, and provide a history and physical exam. Screening tests include a 12-lead resting EKG, complete blood chemistry and complete blood count (CBC), glycated hemoglobin (HbA1c), and a lipid profile. If the results of these tests show that the subject is eligible to participate in the study, a second visit will be scheduled. On the same day as the screening visit, the patient will have an oral glucose tolerance test.

Within 3 months of the screening visit, the subject will return after an overnight fast for a euglycemic clamp study and 2 muscle biopsies. Diabetic subjects will have oral medications discontinued for 3 days before study (metformin and thiazolidinedione treatment will be excluded). Patients taking insulin will have neutral protamine Hagedorn (NPH) discontinued the evening before study, and Glargine will be discontinued the morning and evening on the day before study. An antecubital catheter will be placed for infusion of substances. Deuterated glucose will be used to determine the rates of basal and insulin stimulated glucose uptake. A hand vein will be catheterized and placed in a heated box to arterialize venous blood for measurement of arterial glucose concentrations. One hour later, a percutaneous biopsy of the vastus lateralis muscle will be performed. Biopsy specimens (75-150 mg) will be frozen immediately in liquid nitrogen and stored in liquid nitrogen until they are processed. One hour after the muscle biopsy (two hours after the start of deuterated glucose), a primed-continuous (80 milliunits (mU)/(m^2 per min)) insulin infusion will be started and continued for 120 minutes to quantify the effects of insulin on glucose disposal. Throughout the insulin infusion, an infusion of 20% glucose will be adjusted to maintain euglycemia. Plasma glucose in the diabetics will be allowed to fall during the insulin infusion to euglycemia, where it will be maintained. A second muscle biopsy will be performed in the contralateral leg at the conclusion of the insulin infusion.

  Eligibility

Ages Eligible for Study:   30 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion criteria:

  • Age 30-65 y
  • Healthy lean, obese, or known type 2 diabetic
  • Body Mass Index (BMI) less than 36
  • All nondiabetic subjects must have normal oral glucose tolerance
  • Subjects must have the following laboratory values:

    1. Hematocrit ≥ 35 vol%
    2. Serum creatinine ≤ 1.6 mg/dl
    3. Aspartate aminotransferase (AST) (SGOT)< 2 times upper limit of normal
    4. Alanine aminotransferase (ALT) (SGPT)< 2 times upper limit of normal
    5. Alkaline phosphatase < 2 times upper limit of normal
    6. Triglycerides < 150 mg/dl
    7. Prothrombin time (PT) 11.7 -14.3 seconds
    8. Partial thromboplastin time 23.0-37.0 seconds

Exclusion criteria:

  • No diseases known to affect glucose metabolism other than healthy type 2 diabetes
  • Subjects must not be receiving any of the following medications: thiazide or furosemide diuretics, beta-blockers, or other chronic medications with known adverse effects on glucose tolerance levels unless the patient has been on stable dose of such agents for the past three months before entry into the study. Subjects may be taking a stable dose of estrogens or other hormonal replacement therapy, if the subject has been on these agents for the prior three months. Subjects taking systemic glucocorticoids are excluded.
  • Subjects with a history of clinically significant heart disease (New York Heart Classification greater than grade II; more than non-specific ST-T wave changes on the EKG), peripheral vascular disease (history of claudication), or pulmonary disease (dyspnea on exertion of one flight or less; abnormal breath sounds on auscultation) will not be studied.
  • Recent systemic or pulmonary embolus, untreated high-risk proliferative retinopathy, recent retinal hemorrhage, uncontrolled hypertension, systolic BP>180, diastolic BP>105, autonomic neuropathy, resting heart rate >100, electrolyte abnormalities.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01240252

Locations
United States, Arizona
Mayo Clinic in Arizona
Scottsdale, Arizona, United States, 85259
Sponsors and Collaborators
Mayo Clinic
Investigators
Principal Investigator: Lawrence Mandarino, PhD Mayo Clinic
  More Information

No publications provided

Responsible Party: Lawrence Mandarino, Professor, Mayo Clinic
ClinicalTrials.gov Identifier: NCT01240252     History of Changes
Other Study ID Numbers: 10-003382, R01DK047936
Study First Received: September 29, 2010
Last Updated: June 3, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Mayo Clinic:
diabetes
insulin resistance

Additional relevant MeSH terms:
Diabetes Mellitus
Diabetes Mellitus, Type 2
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Hyperinsulinism
Insulin, Globin Zinc
Insulin
Hypoglycemic Agents
Physiological Effects of Drugs
Pharmacologic Actions

ClinicalTrials.gov processed this record on August 21, 2014