Surgical Removal of Visceral Fat Tissue (Omentectomy) Associated to Bariatric Surgery: Effects on Insulin Sensitivity

Effects of the Surgical Removal of Visceral Fat Tissue (Omentectomy) on Insulin Sensitivity in Grade III Obese Volunteers Subjected to Bariatric Surgery

The intraabdominal fat is associated with insulin resistance, a condition that is in the basis of diabetes, metabolic syndrome and some cardiovascular diseases. It is not clear whether it is the origin of it or a surrogate marker only. We intend to compare the effects of bariatric surgery with versus without omentectomy in morbidly obese people intended to go through bariatric surgery, accessing insulin sensitivity by metabolic tests.

If the visceral fat is causative of insulin resistance, its surgical removal (omentectomy) might lead to improvement of insulin action, as seen in animal studies and in one study with morbidly obese human volunteers.

In order to verify a potential additional benefit of omentectomy combined to Roux-en-Y silastic ring gastric bypass, insulin sensitivity will be studied by the gold-standard test, euglycemic-hyperinsulinemic clamp, since early postoperative follow-up (before significant weight variation), compared to a control group of bariatric surgery (same technique) alone. The variables will be analyzed in the post surgical evolution for correlation to metabolic changes: adiposity-related hormones and cytokines; lipid profile and other cardiovascular risk factors; molecular expression of biopsied subcutaneous adipocytes in vitro; anthropometrics; ultrasonography of abdominal subcutaneous and intra-abdominal fat depots and carotid intima-media thickness (preclinical atherosclerosis evaluation).

Inclusion Criteria:

• Age between 21 and 50 years.
• Female sex.
• BMI between 40 and 50kg/m2.
• Metabolic syndrome (NCEP/ATP III criteria).

Exclusion Criteria:

• Weight variation >5% within 3 months prior to preoperative tests.
• Use of antidiabetic medications within 3 months prior to preoperative tests.
• HbA1c >8%.
• Use of systemic corticosteroids for longer than 1 week within 3 months prior to preoperative tests.
• Hepatic cirrhosis, renal failure or any clinical condition (other than obesity) recognized as impairing insulin sensitivity.
• Present Smoking.