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

Study Overview
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Brief Summary
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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.

Detailed Description
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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).

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

Conditions
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Insulin Resistance, Obesity, Metabolic Syndrome X

Intervention / Treatment
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* Procedure: Roux-en-Y Gastric Bypass plus total omentectomy
* Procedure: Roux-en-Y Gastric Bypass


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: OM group<br> | Procedure: Roux-en-Y Gastric Bypass plus total omentectomy<br>* Roux-en-Y Gastric Bypass plus total omentectomy<br>|
| Active Comparator: CT group<br>Control group | Procedure: Roux-en-Y Gastric Bypass<br>* Roux-en-Y Gastric Bypass without omentectomy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Increase of insulin sensitivity as measured by euglycemic-hyperinsulinemic clamp. |  | one month, six months and one year. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| increase of insulin secretion as measured by intravenous glucose tolerance test |  | one month, six months, one year | 
| regression of carotid intima-media thickness |  | one month, six months, one year | 
| Improvement of the insulin cell signalling in the subcutaneous adipose tissue. |  | one month, six months | 
| increase of adipocytokines linked to greater insulin sensitivity and decrease of others linked to insulin resistance |  | one month, six months, one year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Insulin resistance, Metabolic syndrome X, Obesity, Intra-Abdominal Fat, Omentum, Bariatric surgery, Glucose Clamp Technique, Intravenous Glucose Tolerance Test, Adiponectin, Cytokines