Impaired Adipogenesis in Insulin Resistance: Pilot Clinical and In Vitro Studies

February 1, 2011 updated by: University of Vermont

Obesity is a strong risk factor for developing type 2 diabetes (T2DM), but the reasons for this are not fully understood. In particular, it is not known why some obese people develop T2DM while other obese individuals do not. This study tests whether differences in fat cells (adipocytes) are to blame. Even in adults, fat cells are constantly being formed to replace old fat cells and to respond to the body's need to store excess energy. The ability to form new fat cells may be diminished in some individuals, leading to larger fat cells. These large fat cells secrete hormones that may increase risk for T2DM. This study tests whether fat cells from obese insulin resistant subjects (who are at risk for developing T2DM) form at a slower rate than those from insulin sensitive subjects (who are at lower risk for developing T2DM).

To address this question we will recruit and study two groups of obese subjects, selected to be similar in age, gender and degree of obesity. One group of subjects will be obese and insulin resistant (the OIR group), while the other will be comparably obese, but insulin sensitive (OIS). Subjects will undergo a series of studies to characterize their metabolism including measurement of body fat by DEXA scanning, oral glucose tolerance (a test used to diagnose diabetes) and measurement of insulin sensitivity in response to an infusion of insulin (a research study used to classify patients into the OIR and OIS groups). Small samples of fat (from just under the skin of the belly and the buttocks) will obtained using a needle on two occasions over 12 weeks. During these 12 weeks, subjects will drink a small amount of water that contains a non-radioactive label. This labeled water will allow us to measure the rate of growth of new fat cells in the body. We will also look at the rate of growth of fat cells obtained from these biopsies in the laboratory.

The results of this study may tell us more about why certain obese people develop diabetes and why others do not. This might lead to new ways to prevent or treat T2DM.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Overview of design: To address the specific aims of this study we will recruit and study two groups of obese subjects, selected to be similar in age, gender and BMI. Based on the results of an oral glucose tolerance test (OGTT) and hyperinsulinemic-glucose clamp, one group will be obese and insulin resistant (OIR) and one will be obese and insulin sensitive (OIS). Subjects will undergo measurement of body fat and fat distribution, oral glucose tolerance, in vivo insulin sensitivity, percutaneous needle biopsies of subcutaneous abdominal and gluteal fat and in vivo measurement of SVC and adipocyte turnover using the D2O DNA labeling technique. Adipocyte size and the expression of pro-inflammatory cytokines and adipokines will be compared in the two groups. Primary cultures of preadipocytes will be derived from subjects and proliferation and differentiation measured in vitro and compared to in vivo measures.

Measurement of adipocyte proliferation and differentiation in vivo: The stable isotope technique of Hellerstein et al. for the measurement of slowly dividing cells is based on the incorporation of deuterium oxide (D2O) into DNA. This method has been used to estimate rates of turnover of adipocytes and stromal vascular cells in healthy normal volunteers. It has not, to date, been employed to compare groups of subjects who may differ in their adipogenic propensity. A major objective of the study, therefore, is to evaluate the utility of this approach for quantifying in vivo differences in adipocyte and SVC turnover between groups that vary by insulin sensitivity and to compare the in vivo measures obtained using this technique with in vitro measures of adipogenesis.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

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
    • Vermont
      • South Burlington, Vermont, United States, 05403
        • Fletcher Allen Health Care

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

36 years to 61 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Community sample

Description

Inclusion Criteria:

  • Men and women age 40-65 who are obese (BMI>30)and weight stable for 6 months prior to enrollment.

Exclusion Criteria:

  • Acute or chronic medical conditions that would contraindicate participation in the research testing
  • Pregnant or nursing women
  • HbA1c>6.5%
  • Active alcohol or drug abuse
  • Weight >300 pounds.
  • Smoking

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

  • Observational Models: Case-Control
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
1
Men and Women over age 40 who are obese (BMI>30) and insulin-resistant.
Other: Administration of 70% deuterated water
Subjects will drink 70% deuterated water daily for 8 weeks.
2
Men and women over age 40 who are obese (BMI>30) and insulin-sensitive.
Other: Administration of 70% deuterated water
Subjects will drink 70% deuterated water daily for 8 weeks.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
In vitro rates of adipocyte turnover
Time Frame: 8 weeks
8 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Vermont

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Richard E Pratley, MD, University of Vermont

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

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2008

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2010

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2010

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 16, 2007

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 16, 2007

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 19, 2007

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 2, 2011

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 1, 2011

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2010

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • R21DK080386 (U.S. NIH Grant/Contract)
  • 1R21DK80386-1
  • 958

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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