Tissue Lipids and Insulin Resistance

• Status: Withdrawn
• Trial end date: 1969-12-31
• Target enrollment: 0
• Participant gender: All

Summary

Resistance to the hypoglycemic action of insulin develops within 7 days of bedrest in young, healthy volunteers. We propose that the same event occurs in elderly individuals confined to bed, that alterations in lipid metabolism are, at least in part, responsible for the insulin resistance associated with bedrest, and that the accumulation of intracellular triglyceride (TG) in liver and muscle will play a role in impairing insulin action. Further, we propose that the PPARα (Peroxisome Proliferator-Activated Receptor Alpha) agonist fenofibrate will increase tissue fatty acid disposal by activating mitochondrial oxidative capacity, thereby improving insulin sensitivity.

We will investigate a series of specific hypotheses designed to examine the role of altered lipid metabolism in the development of insulin-resistance associated with bedrest. Further, since inactivity is likely a principal factor in the development of insulin resistance in the elderly, the response to the inactivity imposed by bedrest represents an acceleration of the normal development of insulin resistance in elderly individuals. Therefore, the results of this study will also be pertinent to the understanding of the mechanisms responsible for the natural development of insulin resistance in free-living elderly.

• Phase: N/A
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: University of Arkansas
• Collaborator: National Institutes of Health (NIH)
• Treatments: Fenofibrate

Criteria

Inclusion Criteria:

• Ages between 60 and 85

• Availability of transportation

• Ability to sign informed consent and a score >24 on the 30-item Mini-Mental Status Exam

Exclusion Criteria:

• Subjects with limiting or unstable angina or a cardiology confirmed ECG which demonstrates cardiac abnormalities such as >0.2mV horizontal or downsloping ST segment depression, frequent arrhythmia's (>10PVC/min), or valvular disease.

• Subjects with vascular disease as determined by a combination of risk factors of peripheral atherosclerosis, uncontrolled hypertension, obesity, uncontrolled diabetes, or hypercholesterolemia >250mg/dl.

• Any subjects taking Coumadin adn risk factors of DVT as listed:

1. previous incidents of diagnostically verified DVT

2. major orthopedic, thoracic, abdominal, genitourinary surgery within the last 6 months

3. traumatic fractures of pelvis, femur, or tibia

4. prolonged immobilization: paralysis, pareses or plaster immobilization of lower extremities or prolonged bed rest within the last 6 months

5. estrogen use: estrogen substitution/supplementation within the last 6 months

6. venulitis, thromboangitis obliterans, homocyteinuria within the last 3 months

7. known hypercoagulative abnormalities

8. more than 1 point on the DVT risk assessment score

• Subjects with low hemoglobin or hematocrit (i.e., lower than accepted lab values)

• Any subject that has a chronically elevated systolic pressure >170 or a diastolic pressure >100 will be excluded. Subjects may be included if they are taking blood pressure medication and have a blood pressure below these criteria.

• Any subject that is HIV-seropositive, or has active hepatitis.

• Any subject with an uncontrolled metabolic disease including liver or renal disease.

• Any subject currently taking aspirin that cannot be discontinued for medical reasons.

• Presence of acute illness or metabolically unstable chronic illness.

• Any subject currently on weight-loss diet.

• Inability to abstain from smoking for duration of study.

• Recent ingestion of anabolic steroids or corticosteroids(within 3 months)

• Subjects with atrial fibrillation, history of syncope, angina, or congestive heart failure.

• Subjects with cancer or recently (6 months) treated cancer other than basal cell carcinoma.

• Body mass index greater than 35 or less than 20kg/m2.

• Score of less than 9 on Guralnik/EPESE Scale.

• Any known hypersensitivity to or allergy to fenofibrate.

• Any other condition or event considered exclusionary by the PI and covering faculty physician.