The Role of the Omentum in the Treatment of Morbid Obesity

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.

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.

Subjects undergoing RYGB will be randomized to also have the greater omentum removed at the time of surgery.

Subjects undergoing RYGB will be randomized to NOT have the greater omentum removed at the time of surgery.

Healthy normal weight subjects studied via hyperinsulinemic-euglycemic clamp to obtain reference values for insulin sensitivity and other metabolic parameters.

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.

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

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