Fatty Acid Metabolism and Insulin Sensitivity: the Role of Endurance Exercise

This study has been completed.
Sponsor:
Information provided by:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
ClinicalTrials.gov Identifier:
NCT00795860
First received: November 20, 2008
Last updated: January 12, 2010
Last verified: January 2010
  Purpose

Clearly the effects of diet and exercise are beneficial for obese persons, but the underlying mechanisms for the improvements in metabolic health are not completely clear. Although mounting evidence suggests that alterations in lipid metabolism in persons with abdominal obesity are associated with a several medical complications, including diabetes, little is known about the factors responsible for this effect. The project in this application is designed to examine how the addition of endurance exercise training to a weight-loss program alters whole-body fatty acid availability, uptake, and oxidation as well as the expression of cellular factors that regulate these processes. In addition, we will evaluate whether these alterations are associated with improvements in insulin sensitivity. In the end, these experiments will provide insight into the cellular and whole-body adaptations in fatty acid metabolism in response to weight-loss and exercise training that may lead to enhancement of insulin sensitivity. Identifying relationships between gene expression, whole-body fatty acid metabolism and clinical outcome measurements, such as insulin sensitivity, may lead to improvements in the therapeutic and/or the preventative approach to obesity and its co-morbidities.


Condition Intervention
Insulin Resistance and Type 2 Diabetes
Other: Weight loss

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Fatty Acid Metabolism and Insulin Sensitivity: the Role of Endurance Exercise

Resource links provided by NLM:


Further study details as provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):

Primary Outcome Measures:
  • Insulin sensitivity [ Time Frame: before and after 12% weight loss (3-6 months) ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Rate of fatty acid mobilization in plasma [ Time Frame: Before and after 12% weight loss (3-6 months) ] [ Designated as safety issue: No ]
  • Abundance and activity of Pro-inflammatory factors in skeletal muscle [ Time Frame: Before and after 12% weight loss (3-6 months) ] [ Designated as safety issue: No ]
  • whole body and skeletal muscle oxidative capacity [ Time Frame: Before and after 12% weight loss (3-6 months) ] [ Designated as safety issue: No ]

Enrollment: 36
Study Start Date: June 2003
Study Completion Date: January 2007
Primary Completion Date: January 2007 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: weight loss - diet only
Subjects adhere to a reduced calorie diet until they lose exactly 12% of their initial body weight. After they achieve this weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.
Other: Weight loss
Subjects are randomized to one of two weight loss programs (see arms 1 and 2)until they lose exactly 12% of their initial body weight. After they achieve this weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.
Experimental: weight loss and exercise
Subjects adhere to a reduced calorie diet and perform 4 session of endurance exercise training per week until they lose exactly 12% of their initial body weight. Exercise training consists of stationary bicycle exercise. the exercise duration and intensity ramp up over the first few weeks of training until subjects exercise 45 min per session at an intensity of 85% of their maximal heart rate. 3 of the 4 exercise session each week are supervised by an Exercise physiologist. After they achieve the 12% weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.
Other: Weight loss
Subjects are randomized to one of two weight loss programs (see arms 1 and 2)until they lose exactly 12% of their initial body weight. After they achieve this weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.

Detailed Description:

Despite robust findings emphasizing the importance of weight-loss and exercise for the prevention and management of insulin resistance and Type 2 diabetes, the mechanisms responsible for the improvements in metabolic health are not completely understood. Mounting evidence suggests that abnormalities in fatty acid metabolism in persons with abdominal obesity are associated with insulin resistance. Alterations in fatty acid mobilization and oxidation may be primary adaptations responsible for the improvements in metabolic health after weight-loss and endurance exercise training. We hypothesize that a disparity between muscle fatty acid uptake and oxidation is regulated by the expression of genes and proteins that participate in intracellular transport, trafficking, and metabolism of fatty acids. We believe that alterations in the expression of these factors in response to weight-loss and endurance exercise training will underlie changes in the non-oxidative disposal of fatty acids, and thereby improve insulin sensitivity. We will determine the effects of weight-loss and exercise training on whole-body fatty acid mobilization and oxidation and the expression of factors that regulate these processes in skeletal muscle. In addition, we will evaluate how these alterations are associated with improvements in insulin sensitivity. These studies will provide insight into how cellular alterations with weight-loss and exercise training and the accompanying changes in whole-body fatty acid metabolism may lead to improvements in metabolic health.

  Eligibility

Ages Eligible for Study:   18 Years to 45 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Female
  • Age = 18-45
  • Premenopausal
  • Body mass index ≥ 30 kg/m2
  • Waist circumference ≥ 100 cm

Exclusion Criteria:

  • Evidence of metabolic or cardiovascular disease
  • Pregnancy
  • Allergies to soybeans or eggs
  • Hyperlipidemia (fasting plasma triglyceride concentration > 125 mg/dl)
  • Hematocrit < 34%
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00795860

Locations
United States, Michigan
University of Michigan
Ann Arbor, Michigan, United States, 48109
Sponsors and Collaborators
American Diabetes Association
Investigators
Principal Investigator: Jeffrey Horowitz, PhD University of Michigan
  More Information

Publications:
Responsible Party: Jeffrey F. Horowitz, Associate Professor, The University of Michigan
ClinicalTrials.gov Identifier: NCT00795860     History of Changes
Other Study ID Numbers: ADA - 1-03-JF-10 (completed), ADA grant# 1-03-JF-10
Study First Received: November 20, 2008
Last Updated: January 12, 2010
Health Authority: United States: Institutional Review Board

Keywords provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):
Insulin sensitivity
fat metabolism
inflammation

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

ClinicalTrials.gov processed this record on October 21, 2014