Physical Inactivity and Insulin Resistance in Skeletal Muscle.

April 29, 2021 updated by: University of Kansas Medical Center
The purpose of this study is to determine how a decline in physical activity acutely leads to a decrease in insulin sensitivity in skeletal muscle. The hypothesis is that the loss of insulin sensitivity following physical inactivity is caused by a rapid reduction in skeletal muscle mitochondrial oxidative capacity.

Study Overview

Status

Withdrawn

Conditions

Intervention / Treatment

Detailed Description

In this project we will study two diverse groups of subjects. Group 1 will be subjects who are sedentary, insulin resistant, and have the Metabolic Syndrome. These subjects will be tested for insulin sensitivity at the whole body level, and for key changes in skeletal muscle metabolism at baseline, following 12 weeks of exercise training, and during an acute (1-3 days) period of time following the cessation of exercise training. The design allows us to study the effects of exercise on improving insulin sensitivity and make direct comparisons to a period when insulin sensitivity quickly decreases because of the removal of exercise training. Metformin is a drug commonly prescribed to control insulin resistance and type 2 diabetes. Metformin is thought to have exercise like effects on muscle metabolism and is known to activate a molecule that is de-activated during inactivity. Thus, half of the Metabolic Syndrome subjects will cease exercise training with no treatment while another half will quite exercise training while taking the drug Metformin.

Group 2 subjects will be highly trained endurance athletes. Endurance athletes display high levels of insulin sensitivity that can drop in the hours and days following the cessation of exercise. Thus we will take the same measurements in endurance athletes at baseline during their normal training regimen and in the acute (1-3 days) period following the cessation of exercise training. Again, half of the subjects will be take Metformin during the cessation of exercise in the same fashion as done in group 1.

Studies in both groups seek to determine the event(s) which cause insulin resistance in skeletal muscle following a decrease in physical activity levels. Comparisons between healthy, active individuals and sedentary Metabolic Syndrome subjects may provide additional information about the underlying events that cause insulin resistance.

Study Type

Interventional

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Missouri
      • Columbia, Missouri, United States, 65201
        • Harry S. Truman Memorial Veterans' Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 55 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Selection of inclusion for Metabolic Syndrome Subjects :

Sedentary metabolic syndrome subjects will be 20-55 y of age, overweight to Class I or II obese (BMI 25-39 kg/m2) men and women, who have a fasting glucose of 100 to 125 mg/dl, and at least 2 of 4 other characteristics of the metabolic syndrome which are the following: waist circumference greater than 102 cm in men and 88 cm in women, serum triglyceride concentration greater than 150 mg/dl, HDL-C concentration greater than 40 mg/dl in men and 50 mg/dl in women, and blood pressure greater than 130/85 mmHG.

Selection for inclusion for Endurance Athlete Subjects:

Subjects who report training (running and/or biking) greater than 30 min a day, 4 days a week for at least 1 year will be included. Final inclusion criteria will be a VO2max of greater than 55 ml/kg/min.

To take part in the study, Women must currently be taking birth control or be postmenopausal.

Exclusion Criteria:

  • Subjects will be excluded from the study if they have or are:

Diagnosed cardiovascular disease or diabetes or disease symptoms that could alter their ability to perform exercise, fasting blood glucose of greater than 126 mg/dl, smokers, taking any medications or supplements (e.g., statins, fibrates, metformin, thiazolidinediones, anti-hypertensives (ACE-inhibitors and angiotensin blockers) which could affect blood lipids or insulin sensitivity.

Women who are pregnant or plan to become pregnant during the duration of the study For the Metabolic Syndrome subjects only individuals exercising regularly (more than one 30 min session per week) or have a physically active lifestyle (>8,000 daily steps as measured by a pedometer) will be excluded.

Individuals with an orthopedic limitations for walking. Allergies to drugs used in the study. Past or current liver and/or kidney problems of any nature.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: SINGLE_GROUP
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: 1
Exercise
Behavioral: Exercise
Exercise training will consist of walking and/or jogging on a treadmill 5 out of 7 d each week at ~60% of each subject's predetermined VO2max (75% maximal heart rate as monitored by heart rate monitors), 45 min/session, for 12 weeks. The exercise training will follow a three-stage progression: 1. wk 1 = 30 min, 3 d/wk, 60% VO2max; 2. wk 2 = 30 min, 5 d/wk, 60% VO2max; and 3. wk 3-12 = 45 min, 5 d/wk, 60% VO2max.
ACTIVE_COMPARATOR: 2
Metformin
Drug: Metformin
oral tablet, 1000 mg daily for 17 days

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Insulin sensitivity; following 12 weeks of exercise training and 1 and 3 days of detraining and + or - Metformin.
Time Frame: 12 weeks and 3 days
12 weeks and 3 days

Secondary Outcome Measures

Outcome Measure
Time Frame
PGC-1 alpha transcription and mitochondrial fatty acid oxidation and enzyme activity in skeletal muscle; following 12 weeks of exercise training and 1, 2, and 3 days of detraining and + or - Metformin.
Time Frame: 12 weeks and 3 days
12 weeks and 3 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Kansas Medical Center

Collaborators

US Department of Veterans Affairs

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2009

Primary Completion (ANTICIPATED)

October 1, 2011

Study Completion (ANTICIPATED)

December 1, 2011

Study Registration Dates

First Submitted

September 25, 2007

First Submitted That Met QC Criteria

September 25, 2007

First Posted (ESTIMATE)

September 27, 2007

Study Record Updates

Last Update Posted (ACTUAL)

May 4, 2021

Last Update Submitted That Met QC Criteria

April 29, 2021

Last Verified

August 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1095378

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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