Clinical trial NCT00545805: Surgical Removal of Visceral Fat Tissue (Omentectomy) Associated to Bariatric Surgery: Effects on Insulin Sensitivity
Official title: Effects of the Surgical Removal of Visceral Fat Tissue (Omentectomy) on Insulin Sensitivity in Grade III Obese Volunteers Subjected to Bariatric Surgery
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
PHASE3
Conditions: Insulin Resistance
Obesity
Metabolic Syndrome X
Keywords: Insulin resistance
Metabolic syndrome X
Obesity
Intra-Abdominal Fat
Omentum
Bariatric surgery
Glucose Clamp Technique
Intravenous Glucose Tolerance Test
Adiponectin
Cytokines
Lead sponsor: University of Campinas, Brazil
Sponsor class: OTHER
Collaborators: name: Fundação de Amparo à Pesquisa do Estado de São Paulo
First posted: 2007-10-17
Enrollment: 20
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: 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: 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).

Eligibility criteria: 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.

Primary outcomes:
measure: Increase of insulin sensitivity as measured by euglycemic-hyperinsulinemic clamp.
timeFrame: one month, six months and one year.
Secondary outcomes:
measure: increase of insulin secretion as measured by intravenous glucose tolerance test
timeFrame: one month, six months, one year
measure: regression of carotid intima-media thickness
timeFrame: one month, six months, one year
measure: Improvement of the insulin cell signalling in the subcutaneous adipose tissue.
timeFrame: one month, six months
measure: increase of adipocytokines linked to greater insulin sensitivity and decrease of others linked to insulin resistance
timeFrame: one month, six months, one year
Other outcomes:
Locations:
city: Campinas
country: Brazil
facility: LIMED (Laboratory of Investigation of Metabolism and Diabetes)/GASTROCENTRO/Univeristy of Campinas (UNICAMP)
state: SP
Study officials:
affiliation: University of Campinas (UNICAMP)
name: Marcelo MO Lima, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Campinas (UNICAMP)
name: Bruno Geloneze, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Campinas (UNICAMP)
name: José Carlos Pareja, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Thorne A, Lonnqvist F, Apelman J, Hellers G, Arner P. A pilot study of long-term effects of a novel obesity treatment: omentectomy in connection with adjustable gastric banding. Int J Obes Relat Metab Disord. 2002 Feb;26(2):193-9. doi: 10.1038/sj.ijo.0801871.
citation: Barzilai N, She L, Liu BQ, Vuguin P, Cohen P, Wang J, Rossetti L. Surgical removal of visceral fat reverses hepatic insulin resistance. Diabetes. 1999 Jan;48(1):94-8. doi: 10.2337/diabetes.48.1.94.
citation: Gabriely I, Ma XH, Yang XM, Atzmon G, Rajala MW, Berg AH, Scherer P, Rossetti L, Barzilai N. Removal of visceral fat prevents insulin resistance and glucose intolerance of aging: an adipokine-mediated process? Diabetes. 2002 Oct;51(10):2951-8. doi: 10.2337/diabetes.51.10.2951.
citation: Pitombo C, Araujo EP, De Souza CT, Pareja JC, Geloneze B, Velloso LA. Amelioration of diet-induced diabetes mellitus by removal of visceral fat. J Endocrinol. 2006 Dec;191(3):699-706. doi: 10.1677/joe.1.07069.
citation: Lima MM, Pareja JC, Alegre SM, Geloneze SR, Kahn SE, Astiarraga BD, Chaim EA, Geloneze B. Acute effect of roux-en-y gastric bypass on whole-body insulin sensitivity: a study with the euglycemic-hyperinsulinemic clamp. J Clin Endocrinol Metab. 2010 Aug;95(8):3871-5. doi: 10.1210/jc.2010-0085. Epub 2010 May 19.
citation: Lima MM, Pareja JC, Alegre SM, Geloneze SR, Kahn SE, Astiarraga BD, Chaim EA, Baracat J, Geloneze B. Visceral fat resection in humans: effect on insulin sensitivity, beta-cell function, adipokines, and inflammatory markers. Obesity (Silver Spring). 2013 Mar;21(3):E182-9. doi: 10.1002/oby.20030.