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Identification of Muscle-specific Biomarkers of Fatty Acid Beta-oxidation (FL-68)

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ClinicalTrials.gov Identifier: NCT01494025
Recruitment Status : Completed
First Posted : December 16, 2011
Last Update Posted : August 28, 2012
Information provided by (Responsible Party):

Study Description
Brief Summary:
Elevated fat levels within skeletal muscle cells (intramyocellular lipids) are highly correlated with muscle and whole-body insulin resistance, and more prevalent in obesity. The molecular links and metabolic shifts driving this association remain open to debate, but notably, reduced muscle mitochondrial fatty acid (FA) ß-oxidation is more prevalent among insulin-resistant/diabetic persons. Therefore, discovery of biomarkers reflective of the status of an individual's muscle FA ß-oxidation activity or capacity would have tremendous prognostic and diagnostic value in terms of diabetes. Furthermore, characterization of metabolites associated with muscle mitochondrial fat metabolism should uncover candidate signaling factors which tie FA ß-oxidation to insulin signaling. The investigators propose to identify, for the first time, specific biomarkers of muscle FA ß-oxidation using multiple metabolomic analytical platforms to compare metabolite profiles in samples derived from biological systems displaying disparate muscle fat combustion. The current experiment will test whether plasma metabolites and/or metabolite signatures that track efficient muscular FA ß-oxidation can be experimentally increased in obese, insulin-resistant subjects via a diet-exercise regimen designed to improve muscle fitness and FA combustion.

Condition or disease Intervention/treatment
Obesity Behavioral: Diet and Exercise

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Study Design

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 13 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Identification of Muscle-specific Biomarkers of Fatty Acid Beta-oxidation
Study Start Date : October 2009
Primary Completion Date : June 2012
Study Completion Date : July 2012

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U.S. FDA Resources

Arms and Interventions

Arm Intervention/treatment
Experimental: Diet and Exercise Behavioral: Diet and Exercise
Subjects underwent a diet regimen targeted to elicit a 10% weight loss. Diets were designed based on the US Dietary Guidelines with caloric deficits individualized for each subject. Aerobic exercise was monitored over approximately 14 weeks, several times per week, to elicit significantly increased VO2max.

Outcome Measures

Primary Outcome Measures :
  1. Change in VO2max [ Time Frame: Week 1 vs. Week 16 ]
    Overnight fasted subjects will start the test at a low cycle ergometer resistance level and encouraged to maintain a steady rate of pedaling, and resistance will increase at 2-min intervals until volitional fatigue. Indirect calorimetry will be used to measure VO2 and CO2 continuously during the exercise test. Subjects will receive a pre-test ECG, breath volume test and medical exam to assure the subject has no underlying medical problems that would put them at an undue risk during the exercise tests.

  2. Change in Body Composition (BODPOD) [ Time Frame: Week 1 vs. Week 16 ]
    Body fat mass and fat-free mass will be measured using the BOD POD. Subjects will be asked to change into a provided form-fitting swimsuit or single layer compression shorts and single layer jog bra for women. Subjects will also be asked to wear a provided swim cap to compress the hair on their head. After measuring height and weight, they will sit comfortably in the BOD POD and limit their movement while breathing normally. During the last section of the test subjects will be asked to breathe into a tube and give three puffs when indicated by the computer screen.

  3. Change in Insulin Sensitivity [ Time Frame: Week 1 vs. Week 16 ]
    OGTT (oral glucose tolerance test) A standard oral 75 g glucose tolerance test (OGTT) will be administered and the insulin sensitivity index calculated as per Matsuda and DeFronzo. For screening a blood sample will be taken after 2 hours. For the test week, blood samples will be taken at 0, 15, 30, 60, 90, and 120 min post-glucose ingestion (up to 8 mL of blood will be obtained/timepoint).

  4. Change in Metabolite Profiling and Metabolomics [ Time Frame: Week 1 vs. Week 16 ]
    EDTA plasma from overnight fasted subjects and samples derived from exercise tests obtained in the pre-intervention and post-intervention test weeks will be analyzed. Samples will be analyzed using several mass spec based metabolomics platforms. Exercise samples are derived from subjects undergoing 30-minutes of submax exercise (45% VO2max) collected every 5 minutes, plus samples collected during a 20-minute cool-down phase.

  5. Change in Body Composition (DXA) [ Time Frame: Week 1 vs. Week 16 ]
    Body fat mass and fat-free mass will be measured by DXA using a whole body scan. The scan will be performed at the beginning of the study and after the diet and exercise intervention. Our technical staff at WHNRC is trained and certified in the DXA method. The volunteer will wear light-weight surgical scrubs. The scan time takes no longer than 30 minutes to complete, with a radiation exposure less than 0.1 mrem. As subjects will be menstruating during the test week, there is no risk to a developing fetus. A pregnancy test will be offered but not required.

  6. Change in Body Weight [ Time Frame: Week 1 vs. Week 16 ]
    Body weights are measured on a calibrated scale approximately on a weekly basis throughout the study, and daily during pre-intervention Test Week 1 and post-intervention Test Week 2.

Eligibility Criteria

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Ages Eligible for Study:   30 Years to 50 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • female
  • age 30-50
  • menstruating with regularity
  • BMI between 30- 37.5 with stable body weight (<5% change) over last 6 mos
  • waist to hip ratio >0.9
  • sedentary lifestyle (typical exercise < 30 min. per week)
  • non-smoker
  • evidence for pre-diabetes (hyperinsulinemia and/or blood glucose > 100 < 126 mg/dl)

Exclusion Criteria:

  • any clinically significant abnormal laboratory values
  • any clinical signs of infection (i.e., fever)
  • any chronic diseases
  • any personal history of cardiovascular disease
  • clinically-significant elevation in blood pressure (≥130/85)
  • diabetes or other chronic disease
  • any regular medications or drug abuse
  • pregnancy or lactation
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01494025

United States, California
Western Human Nutrition Research Center
Davis, California, United States, 95616
Sponsors and Collaborators
USDA, Western Human Nutrition Research Center
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of California, Davis
University of Alabama at Birmingham
University of Ottawa
Case Western Reserve University
Principal Investigator: Sean H Adams, PHD USDA, Western Human Nutrition Research Center
More Information

Responsible Party: USDA, Western Human Nutrition Research Center
ClinicalTrials.gov Identifier: NCT01494025     History of Changes
Other Study ID Numbers: 200816512
R01DK078328 ( U.S. NIH Grant/Contract )
First Posted: December 16, 2011    Key Record Dates
Last Update Posted: August 28, 2012
Last Verified: August 2012

Keywords provided by USDA, Western Human Nutrition Research Center: