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The Role of the Omentum in the Treatment of Morbid Obesity

This study has been completed.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Information provided by (Responsible Party):
Naji Abumrad, Vanderbilt University Medical Center Identifier:
First received: September 13, 2005
Last updated: January 30, 2017
Last verified: January 2017
The purpose of this research is to determine some of the reasons that blood sugar and insulin levels improve after bariatric surgery but before weight loss begins, as well as why people respond differently to weight loss surgery. It will also examine whether removing the fat around the stomach and large intestine (the omentum) will improve weight loss. Finally, it will see why there are differences between Whites and African Americans who have weight loss surgery.

Condition Intervention
Procedure: omentectomy

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Participant
Primary Purpose: Basic Science
Official Title: The Role of the Omentum in the Treatment of Morbid Obesity

Further study details as provided by Vanderbilt University Medical Center:

Primary Outcome Measures:
  • change in insulin sensitivity [ Time Frame: 5 year ]

Secondary Outcome Measures:
  • Weight loss [ Time Frame: 5 years ]

Enrollment: 66
Actual Study Start Date: January 2005
Study Completion Date: October 2011
Primary Completion Date: October 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: RYGB with omentectomy
Subjects undergoing RYGB will be randomized to also have the greater omentum removed at the time of surgery.
Procedure: omentectomy
RYGB with omentectomy
No Intervention: RYGB without omentectomy
Subjects undergoing RYGB will be randomized to NOT have the greater omentum removed at the time of surgery.
No Intervention: Normal body weight
Healthy normal weight subjects studied via hyperinsulinemic-euglycemic clamp to obtain reference values for insulin sensitivity and other metabolic parameters.
No Intervention: Tissue samples
Tissue samples (omental fat, subcutaneous fat, muscle,and blood)are obtained from subjects of varying weights during abdominal surgery in order to compare various parameters, including inflammation, oxidative stress, and gene expression, among tissues across weight classes.

Detailed Description:

The purpose of this research is to tease out the mechanisms related to changes in insulin sensitivity, metabolism, hormones, and body composition following bariatric surgery. Because preliminary data indicate differing responses to this surgery, both Caucasian and African American adults, scheduled for RYGB, are being recruited to participate. It is believed that the omentum contributes to hepatic insulin resistance, both because of the increased delivery of NEFAs via the portal vein, and the increased production of cytokines. Because of this, it is postulated that removing the omentum as part of bariatric surgery will speed up the reversal of insulin resistance and diminish racial differences in response to the surgery.

Data are derived from tissue and blood samples obtained operatively (from individuals having bariatric surgery and other abdominal operations), as well as during hyperinsulinemic-euglycemic clamps, from indirect calorimetry, DEXA, Health-related Quality of Life surveys, and 24-hour urine samples. There were 66 participants randomized to omentectomy/no omentectomy. A post hoc data power analysis determined that this number of subjects is sufficient for data analysis.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • BMI > 40
  • BMI > 35 with co-morbidities
  • normal creatinine/liver labs
  • insurance approval for RYGB or resources to self-pay
  • proximity to Nashville, TN

Exclusion Criteria:

  • use of anticoagulants, steroids, therapeutic niacin
  • previous bariatric surgery
  Contacts and Locations
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Please refer to this study by its identifier: NCT00212160

United States, Tennessee
Vanderbilt University Medical Center
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Vanderbilt University Medical Center
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Principal Investigator: Naji N Abumrad, MD Vanderbilt University Medical Center
  More Information


Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Naji Abumrad, Chairman, Department of Surgery, Vanderbilt University Medical Center Identifier: NCT00212160     History of Changes
Obsolete Identifiers: NCT00247598
Other Study ID Numbers: IRB #040572
R01DK070860 ( US NIH Grant/Contract Award Number )
3R01DK070860-01S1 ( US NIH Grant/Contract Award Number )
Study First Received: September 13, 2005
Last Updated: January 30, 2017

Additional relevant MeSH terms:
Obesity, Morbid
Nutrition Disorders
Body Weight
Signs and Symptoms processed this record on May 25, 2017