The Reduction of Visceral Adipose Tissue after Roux-en-Y Gastric Bypass Is more Pronounced in Patients with Impaired Glucose Metabolism

Abstract

PurposeVisceral adipose tissue (VAT) is associated with cardiometabolic risk factors and insulin resistance. The physiological mechanisms underlying the benefits of Roux-en-Y gastric bypass surgery (RYGB) on glucose metabolism remain incompletely understood. The impact of RYGB on VAT was assessed among three groups of patients stratified by their glucose tolerance before surgery.MethodsForty-four obese women were categorized into normoglycemia (n = 21), impaired glucose tolerance (IGT, n = 18) and diabetes (n = 5) before surgery. Body composition measured by dual-energy X-ray absorptiometry (DXA) was performed before surgery, 6 months and 12 months after.ResultsThe three groups had comparable mean age (mean 38.6 ± SD 9.9) and BMI at baseline (41.9 ± 4.3 kg/m2). After 12 months, total weight loss (mean 35.1% ± 7.5) and excess weight loss (91.1% ± 25.1) were similar between groups. Pre-surgery mean VAT was significantly higher in diabetes (mean 2495 ± 616 g) than in normoglycemia (1750 ± 617 g, p = 0.02). The percentage of VAT to total body fat was significantly higher in diabetes (mean 4.4% ± 0.9) compared to normoglycemia (2.9% ± 0.8, p = 0.003). Twelve months after surgery, VAT loss was significantly greater among patients with diabetes (mean 1927 ± 413 g) compared to normoglycemia (1202 ± 450, p = 0.009).ConclusionsRYGB leads to important VAT loss, and this loss is greater in patients with diabetes prior to surgery. As VAT is associated with insulin resistance, this reduction may account for the profound impact of this surgery on glucose metabolism.

Validity of dual‐energy x‐ray absorptiometry for estimation of visceral adipose tissue and visceral adipose tissue change after surgery‐induced weight loss in women with severe obesity

“…If greater VAT accumulates within the DXA ROI, then DXA’s estimates would be larger; whereas, if the excess VAT falls outside the ROI, then DXA’s estimates would be smaller. We do not believe that menopausal transition affected our finding because our estimate of VAT by DXA 12 months after surgery matches that which has been reported in other studies of women of perimenopausal age (25). Future studies should assess menopausal status when evaluating changes in VAT by DXA.…”

Long-term body composition improvement in post-menopausal women following bariatric surgery: a cross-sectional and case–control study

“…We described a higher VAT in operated women with T2D at the time of surgery as compared to non-diabetic. Previous studies reported that diabetic patients have greater amount of VAT before surgery compared to normoglycaemic subjects (7). These data highlight the association between fat distribution and T2D, even later after surgery, via the well-known lipolytic and pro-inflammatory profile of the VAT.…”

“…Body composition analysis was assessed in both groups using Lunar iDXA (GE Healthcare, Madison, WI, USA) (7). Participants were placed centered on the scanning field in a supine position, with palms down and arms at sides, slightly separated from the trunk.…”

“…It is a restrictive and malabsorptive surgery that results in a decrease in body fat mass (FM) including visceral adipose tissue (VAT) and an improvement in metabolic parameters and cardiovascular risk (5). However, it also leads to inexorable loss in lean mass (LM), ranging from 10% to 45% twelve months after RYBG (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). While long-term studies on body composition (BC) after bariatric surgery are scarce, significant loss in LM during the first 18 months post-RYGB and a tendency for LM stabilization or slight increase afterwards have been reported (6,15,16).…”

Impact of Bariatric Surgery on Adipose Tissue Biology

“…During the first year, coinciding with the rapid weight loss phase after BS, both SAT [ 126 , 127 , 128 , 129 , 130 ] and VAT [ 126 , 127 , 128 , 129 , 130 , 134 , 135 ] depots progressively reduce their size, and this is accompanied by a reduction in the area of subcutaneous [ 136 , 137 , 138 ] and visceral [ 138 ] adipocytes, respectively. A large adipocyte size was independently associated with a lower incidence of insulin resistance 6 months after RYGBP [ 136 ].…”