Fat Cell Size in Insulin Resistance

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT00341406
Recruitment Status : Recruiting
First Posted : June 21, 2006
Last Update Posted : May 24, 2018
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) )

Brief Summary:

This study, conducted at Stanford University in Palo Alto, California, will examine how insulin metabolism and cardiovascular risk are altered in response to weight loss. Insulin is a natural hormone that causes cells to remove glucose (sugar) from the blood. People who are insulin-sensitive remove glucose efficiently. People who are insulin-resistant require more insulin to remove glucose from the blood.

Adult volunteers will be recruited for this study through advertisements in local newspapers in communities around Stanford University.

Participants will undergo the following tests and procedures:

  • Insulin sensitivity testing: Before beginning the study, participants will be tested for insulin sensitivity. For the test, two small catheters (plastic tubes) are placed into two veins - one for infusing glucose, insulin, and sandostatin (a drug that blocks insulin secretion from the pancreas), and one for drawing blood samples. The infusions are done over 3 hours. Blood samples are collected before, during, and at the end of the study to measure how well the cells remove glucose from the blood in response to insulin.
  • Research diet: Participants are assigned to a low-calorie diet tailored to the individual's metabolic rate. The diets contain either 40 or 60 percent of total calories as carbohydrates, 40 or 20 percent as fat, and the rest as protein. People with type 2 diabetes who are taking diabetes medicine with have a diet of 45 to 50 percent carbohydrates, 35 to 40 percent fat, and the rest protein.
  • Meal profile: Before beginning the diet and after 4 months on the diet, participants are tested for the effects of the various study diets on control of blood sugar and fats. On the day of each test, participants have a physical examination and provide a medical history. Then, a small catheter is placed in a vein. Blood samples are drawn before breakfast and then hourly for up to 8 hours.
  • Participants who are diabetic are randomly assigned to take one of three diabetes medications - rosiglitazone, glucophage, or a sulfonylurea compound - to help control blood glucose levels.
  • Magnetic resonance imaging: This diagnostic test uses a strong magnetic field and radio waves to show structural and chemical changes in tissues. During the scan, the participant lies on a table in a narrow cylinder containing a magnetic field, wearing ear plugs to muffle loud knocking and thumping sounds that occur during the scanning process. He or she can speak with a staff member via an intercom system at all times during the procedure.

In addition to these procedures, patients may be asked to have a fat cell biopsy. This is done to determine whether insulin-resistant people have fewer fat cells but more fat per cell than insulin-sensitive people. For this test, a small piece of fat tissue is surgically removed, under local anesthetic, from an area of the lower abdomen. With the participant's consent, genetic testing may be done on the fat tissue sample to look for genes that may link central obesity to insulin resistance.

Some participants may be asked to be followed for an additional 3 months after completion of the study for a continued weight loss program. The follow-up includes weekly visits for weight measurements and a review of food records.

Condition or disease
Obesity Adipose Cell Turn Over

Detailed Description:
Little is known about the turnover of adipose cells in the fat depots of normal animals and human subjects. However, microarray analysis of adipose cell gene expression in high risk insulin-resistant human subjects suggests that a reduced rate of adipose cell turnover is associated with enhanced adipose cell size and systemic insulin resistance. New technology now permits a detailed analysis of adipose cell size including the detection of smaller cells which may be in the process of active differentiation. We propose to examine the relationship between adipose cell size distribution and systemic insulin resistance in obese human subjects. Adipose tissue biopsies will be obtained at Stanford University under protocols and consent forms approved by the Stanford University IRB. Only procedures already being performed on subjects under these protocols will be used.

Study Type : Observational
Estimated Enrollment : 9999999 participants
Official Title: Adipose Cell Size In Human Insulin Resistance
Study Start Date : September 4, 2003

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Without regard to gender, race, or socioeconomic status, all subjects will be adult men and women. The racial/ethnic composition of the study population will be reflective of the communities surrounding Stanford University. Subjects will be recruited through placement of advertisements in local newspapers, but no subjects will be seen at NIH.

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 identifier (NCT number): NCT00341406

Contact: Michelle L Ashmus, R.N. (301) 594-5953
Contact: Arthur Sherman, Ph.D. (301) 496-4325

United States, Maryland
National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK), 9000 Recruiting
Bethesda, Maryland, United States, 20892
Contact: Samuel Cushman, Ph.D.    301-496-5953   
Sponsors and Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Principal Investigator: Arthur Sherman, Ph.D. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Responsible Party: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Identifier: NCT00341406     History of Changes
Other Study ID Numbers: 999903290
First Posted: June 21, 2006    Key Record Dates
Last Update Posted: May 24, 2018
Last Verified: September 21, 2017

Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) ):
Type 2 Diabetes Mellitus
Adipose Cell Turn Over

Additional relevant MeSH terms:
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases