Effect of Bariatric Surgery on Adipose Tissue Glucose Metabolism in Different Depots in Patients With or Without Type 2 Diabetes

Abstract

OBJECTIVEWe investigated fat distribution and tissue-specific insulin-stimulated glucose uptake (GU) in seven fat compartments (visceral and subcutaneous) and skeletal muscle in morbidly obese patients with (T2D) and without (ND) type 2 diabetes before and 6 months after bariatric surgery. RESEARCH DESIGN AND METHODSA total of 23 obese patients (BMI 43.0 6 3.6 kg/m 2 ; 9 T2D and 14 ND) were recruited from a larger, randomized multicenter SLEEVEPASS study. MRI (for fat distribution) and [18 F]-fluorodeoxyglucose PET (for GU) studies were performed for the obese patients before and 6 months postsurgery; 10 lean subjects served as control subjects and were studied once. RESULTSAt baseline, visceral fat GU was 30 6 7% of muscle GU in control subjects and 57 6 5% in obese patients. Visceral and deep subcutaneous fat were more abundant (despite same total fat mass) and less insulin sensitive in T2D than ND; in both, GU was impaired compared with control subjects. Postsurgery, visceral fat mass decreased (∼40%) more than subcutaneous fat (7%). Tissue-specific GU was improved, but not normalized, at all sites in T2D and ND alike. The contribution of visceral fat to whole-body GU was greater in T2D than ND but decreased similarly with surgery. Subcutaneous fat made a fourfold greater contribution to whole-body GU in obese versus lean subjects (15% vs. 4%) both before and after surgery. CONCLUSIONSBariatric surgery leads to sustained weight loss and improves tissue-specific glucose metabolism in morbidly obese patients. We conclude that 1) enhanced visceral fat accumulation is a feature of T2D, 2) severe obesity compromises muscle insulin sensitivity more than fat insulin sensitivity, and 3) fat mass expansion is a sink for plasma glucose.Visceral fat (VF) and subcutaneous fat (SC) are structurally, metabolically, and functionally distinct, albeit both contribute to obesity (1). Abdominal SC fat has clearly defined, metabolically distinct deep and superficial layers separated by the Scarpa fascia (2,3). Research suggests that the deep layers are metabolically more active

The short-term and long-term effects of bariatric/metabolic surgery on subcutaneous adipose tissue inflammation in humans

“…Although it is known that differences in the absolute expression of pro-inflammatory cytokines exist between visceral and subcutaneous adipose tissue in humans, gene expression patterns in both depots are equivalently associated with obesity [43, 57] and metabolic disease [43, 58, 59]. Related to this issue, Dadson et al [60] observed differences in insulin-stimulated glucose uptake between visceral and subcutaneous adipose tissue depots. However, the relative change in glucose uptake following bariatric/metabolic surgery was similar in both depots [60].…”

“…Related to this issue, Dadson et al [60] observed differences in insulin-stimulated glucose uptake between visceral and subcutaneous adipose tissue depots. However, the relative change in glucose uptake following bariatric/metabolic surgery was similar in both depots [60]. Collectively, these findings suggest that assessments based solely on subcutaneous adipose tissue samples are not likely to grossly misrepresent the underlying processes associated with obesity-driven inflammation and metabolic dysfunction.…”

Reversibility of myocardial metabolism and remodelling in morbidly obese patients 6 months after bariatric surgery

“…The participant recruitment process has been described previously . Briefly, morbidly obese participants were recruited from people undergoing bariatric surgery as part of their normal treatment at the Hospital District of Southwest Finland.…”

“…The participant recruitment process has been described previously. 20,21 Briefly, morbidly obese participants were recruited from people undergoing bariatric surgery as part of their normal treatment at the Hospital District of Southwest Finland. The surgical inclusion criteria were age 18-60 years and body mass index (BMI) ≥40 kg/m 2 (or ≥35 kg/m 2 with an additional obesity-related comorbidity).…”

PET imaging during hypoglycaemia to study adipose tissue metabolism

“…The amount and distribution of adipose tissue (AT) are important contributing factors in the development of insulin resistance and type 2 diabetes . While hepatic and muscle insulin resistance are generally regarded as the key factors in disrupted glucose homeostasis in type 2 diabetes, AT glucose handling could also play an important role. AT has been shown to make a considerable contribution to insulin‐stimulated glucose uptake from the circulation .…”