Fat Induced Insulin Resistance and Atherosclerosis

The overall objective of the current proposal is to strengthen the putative link between FFA induced insulin resistance and atherosclerotic vascular disease (ASVD). To this end, the investigators will test the following hypotheses: 1) that FFA induced activation of protein kinase C βII (PKC β II) and δ and other serine kinases such as IκB kinase (IKK) in human muscle is associated with a decrease in insulin stimulated tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1) and of IRS-1 associated phosphatidylinositol 3 (PI3) kinase; 2) that these changes precede the development of insulin resistance; 3) that the decrease in IκB-α results in activation of nuclear factor κB (NFκB) and the expression of adhesion molecules and cytokines; 4) that PKC and IKK are involved in producing insulin resistance and activation of the IκB/ NFκB pathway and lastly 5) that the same mechanisms operative in healthy volunteers are also operative in patients with T2DM.The investigators will test these hypotheses in normal (current) and diabetic volunteers (previously completed) . Euglycemic-hyperinsulinemic clamps will be performed with and without co-infusion of lipid plus heparin (to raise FFAs) and by obtaining serial muscle and fat biopsies and blood samples will be obtained for measurement of substrates, hormones, enzymes and metabolites.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus; Insulin Resistance; Other Fatty Acid Oxidation Disorders
• Intervention / Treatment: Other: Lipid/heparin

Detailed Description

All subjects will be admitted to the GCRC in the afternoon before the tests (Day 1) and will undergo a thorough physical examination. Routine admission lab tests (including a 2-h 75g OGTT) and body composition measurements will be obtained. A standardized dinner will be served at ~ 6PM. The next (Day 2) after an overnight fast, IV lines will be placed (arms will be wrapped with a heating blanket and kept at 70ºF to arterialize venous blood).

The following studies will be performed.

Thirty-two healthy volunteers will undergo euglycemic - hyperinsulinemic clamping without radioactive isotopes and with (n=16) and without (n=16) lipid/heparin co-infusion for 8 hours.

Serial (at 0, 1, 2 and 4 h) muscle and fat biopsies and serial blood samples (q' 1 h) will be obtained. The following measurements will be obtained in muscle biopsies and T-cell extracts: PKC-βI and II and PKC-δ, IKK, IκB-α, NFκB, IRS-1 tyrosine phosphorylation, IRS-1 associated PI3- kinase, ICAM, VCAM and e-selectin mRNAs.

• Study Type: Interventional
• Enrollment (Actual): 86
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19140
      • Temple University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• The investigators plan to study 32 healthy normal subjects.
• These volunteers will be male and female, between the ages of 30 and 75 years and of all races.
• None of these volunteers will have a family history of diabetes or any other endocrine disorder and none will be taking any medications.

Exclusion Criteria:

• Patients with chronic health problems including cardiovascular, pulmonary, hematologic (*Hb< 9 g/dl), renal (serum creatinine > 1.8 mg/dl), hepatic disease, AIDS or other chronic infectious disease will be excluded.
• Pregnant women will be excluded. Non-pregnant women will be studied during the follicular phase of their menstrual cycle. If needed, a pregnancy test will be performed to exclude pregnancy.

Study Plan

How is the study designed?

Design Details

• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Lipid/heparin; 16 healthy volunteers will undergo euglycemic - hyperinsulinemic clamping without radioactive isotopes and with (n=16) lipid/heparin co-infusion for 8 hours.	Other: Lipid/heparin; 32 healthy volunteers will undergo euglycemic - hyperinsulinemic clamping without radioactive isotopes and with (n=16) and without (n=16) lipid/heparin co-infusion for 8 hours. Serial (at 0, 1, 2 and 4 h) muscle and fat biopsies and serial blood samples (q' 1 h) will be obtained. The following measurements will be obtained in muscle biopsies and T-cell extracts: PKC-βI and II and PKC-δ, IKK, IκB-α, NFκB, IRS-1 tyrosine phosphorylation, IRS-1 associated PI3- kinase, ICAM, VCAM and e-selectin mRNAs.
Placebo Comparator: Control; 16 healthy volunteers will undergo euglycemic - hyperinsulinemic clamping without radioactive isotopes and without (n=16) lipid/heparin co-infusion for 8 hours.	Other: Lipid/heparin; 32 healthy volunteers will undergo euglycemic - hyperinsulinemic clamping without radioactive isotopes and with (n=16) and without (n=16) lipid/heparin co-infusion for 8 hours. Serial (at 0, 1, 2 and 4 h) muscle and fat biopsies and serial blood samples (q' 1 h) will be obtained. The following measurements will be obtained in muscle biopsies and T-cell extracts: PKC-βI and II and PKC-δ, IKK, IκB-α, NFκB, IRS-1 tyrosine phosphorylation, IRS-1 associated PI3- kinase, ICAM, VCAM and e-selectin mRNAs.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
protein kinase C enzyme activity in tissue samples	The following measurements will be obtained in muscle biopsies: PKC-βI and II and PKC-δ, IKK, IκB-α, NFκB, IRS-1 tyrosine phosphorylation, IRS-1 associated PI3- kinase, ICAM, VCAM and e-selectin mRNAs.	baseline, 1 hour, 2 hour, 4 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin sensitivity	Glucose infusion rates during the 8 hour euglycemic-hyperinsulemic clamp will be calculated.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours
Free fatty acids	Free fatty acid levels will be measured by standard methods in the investigator's laboratory	0, 1 2, 3, 4, 5, 6, 7 ,8 hours
protein kinase C enzyme activity in T cells	T cell extracts will be used to assay PKC, IKK, IκB-α, NFκB and VCAM, ICAM and e-selectin mRNA.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours

Collaborators and Investigators

• Sponsor: Temple University
• Investigators: Principal Investigator: Guenther Boden, MD, Temple University

Study record dates

Study Major Dates

• Study Start: June 1, 2003
• Primary Completion (Actual): December 1, 2014
• Study Completion (Actual): June 1, 2015

Study Registration Dates

• First Submitted: January 22, 2015
• First Submitted That Met QC Criteria: January 27, 2015
• First Posted (Estimate): January 28, 2015

Study Record Updates

• Last Update Posted (Estimate): November 25, 2015
• Last Update Submitted That Met QC Criteria: November 23, 2015
• Last Verified: November 1, 2015

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Glucose Metabolism Disorders; Metabolic Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Hyperinsulinism; Insulin Resistance; Atherosclerosis; Molecular Mechanisms of Pharmacological Action; Fibrinolytic Agents; Fibrin Modulating Agents; Anticoagulants; Heparin
• Other Study ID Numbers: 4148