Blood Flow Responses to an Oral Glucose Tolerance Test in Type 2 Diabetes (OGTT)

September 23, 2015 updated by: University of Kansas Medical Center

Acute Cardiovascular and Metabolic Effects of Exercise Training in Individuals

The investigators wish to determine whether a short period of exercise training (5-10 days) improves the metabolic and cardiovascular response of people with or at risk of developing type 2 diabetes to eating a meal. In healthy people, blood flow to skeletal muscles increases after eating a meal, and this helps to regulate blood sugar levels by delivering blood sugar to muscles where it can be stored or metabolized. In people with or at risk of type 2 diabetes, blood flow does not increase as much after eating a meal, and this may contribute to elevated blood sugar concentrations observed in these individuals. The investigators wish to determine whether exercise can improve this response.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Insulin resistance is characterized by decreased sensitivity to the metabolic actions of insulin (glucose disposal) and is a hallmark of obesity and type 2 diabetes (T2D). Insulin resistance is also a prominent component of cardiovascular diseases (CVD), including hypertension, coronary artery disease, and atherosclerosis, which are characterized by endothelial dysfunction. Insulin stimulates two distinct signaling pathways in the endothelium. One produces the vasodilator nitric oxide (NO) through the insulin receptor substrate-1(IRS-1)/endothelial NO synthase (eNOS) pathway while the other stimulates production of endothelin-1 (ET-1), a vasoconstrictor, through the mitogen activated protein kinase (MAPK) pathway. Insulin-mediated glucose disposal is largely dependent upon the vasodilatory effects of insulin; however, in T2D, insulin-stimulated dilation is impaired as a result of an imbalance in NO and ET-1 production, leading to diminished microvascular perfusion and skeletal muscle glucose delivery in response to insulin. The effects of exercise on insulin signaling/action in the endothelium are not fully understood. The purpose of this study is determine the acute effects of aerobic exercise training on cardiometabolic responses to meal ingestion in individuals with insulin resistance or T2D. We will recruit 30 previously sedentary (<60 minutes of planned exercise/week) men and women with insulin resistance (pre-diabetes) or T2D for participation in this study. Participants will undergo a screening procedure, including telephone screening and physical examination, as well as determination of body composition and fitness. Participants will be asked to complete 5-10 days of supervised exercise training and will undergo testing to assess cardiovascular and metabolic responses to an oral glucose tolerance test, including muscle sympathetic nerve activity, blood flow, and circulating glucose and insulin concentrations at baseline and following training. In addition, participants will use continuous glucose monitoring systems for 3 days at baseline and during 3 days of exercise training to assess the effects of acute exercise on postprandial glucose responses to mixed meals in free-living individuals. The overall aim of the project is to determine whether or not acute exercise training influences postprandial metabolic, vascular or autonomic nervous system responses in individuals with insulin resistance or T2D.

Study Type

Interventional

Enrollment (Actual)

30

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
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • University of Kansas Medical Center

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

30 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Insulin resistant: diagnosed with pre-diabetes or fasting blood glucose >/= 100 mg/dL
  • T2D: diagnosed by primary care physician
  • BMI: less than 43 kg/m2
  • Age: 30-65

Exclusion Criteria:

  • Smoking
  • Insulin use (other than once daily)
  • Underlying conditions that limit ability to exercise safely
  • Recent weight gain or loss (> 5% of body weight in 3 months)
  • Physically active (> 30 min aerobic exercise, 2 d/wk)
  • Recent (< 3 mo) changes in medication use or dose
  • Uncontrolled T2D (HbA1c > 10%)
  • Advanced retinopathy or neuropathy
  • Pregnancy

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: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Exercise
5-10d exercise training
Behavioral: Exercise
short period of exercise training (5-10 days)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
The overall aim of the project is to determine whether or not acute exercise training influences postprandial metabolic, vascular or autonomic nervous system responses in individuals with insulin resistance or T2D.
Time Frame: 2 hours
2 hours

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

Investigators

  • Principal Investigator: John P Thyfault, PhD, University of Kansas Medical Center

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

August 1, 2009

Primary Completion (Actual)

May 1, 2010

Study Completion (Actual)

September 1, 2010

Study Registration Dates

First Submitted

September 4, 2009

First Submitted That Met QC Criteria

September 4, 2009

First Posted (Estimate)

September 7, 2009

Study Record Updates

Last Update Posted (Estimate)

September 24, 2015

Last Update Submitted That Met QC Criteria

September 23, 2015

Last Verified

September 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MUIRB1135317

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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