Deep Subcutaneous Adipose Tissue: A Distinct Abdominal Adipose Depot

Abstract

Obesity. 2007;15:1933-1943. Objective: Abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) display significant metabolic differences, with VAT showing a functional association to metabolic/cardiovascular disorders. A third abdominal adipose layer, derived by the division of SAT and identified as deep subcutaneous adipose tissue (dSAT), may play a significant and independent metabolic role. The aim of this study was to evaluate depot-specific differences in the expression of proteins key to adipocyte metabolism in a lean population to establish a potential physiologic role for dSAT. Research Methods and Procedures: Adipocytes and preadipocytes were isolated from whole biopsies taken from superficial SAT (sSAT), dSAT, and VAT samples obtained from 10 healthy normal weight patients (7 women and 3 men), with a mean age of 56.4 Ϯ 4.04 years and a mean BMI of 23.1 Ϯ 0.5 kg/m 2 . Samples were evaluated for depot-specific differences in insulin sensitivity using adiponectin, glucose transport protein 4 (GLUT4), and resistin mRNA and protein expression, glucocorticoid metabolism by 11␤-hydroxysteroid dehydrogenase type-1 (11␤-HSD1) expression, and alterations in the adipokines leptin and tumor necrosis factor-␣ (TNF-␣). Results: Although no regional differences in expression were observed for adiponectin or TNF-␣, dSAT whole biopsies and adipocytes, while intermediary to both sSAT and VAT, reflected more of the VAT expression profile of 11␤-HSD1, leptin, and resistin. Only in the case of the intracellular pool of GLUT4 proteins in whole biopsies was an independent pattern of expression observed for dSAT. In an evaluation of the homeostatic model, dSAT 11␤-HSD1 protein (r ϭ 0.9573, p ϭ 0.0002) and TNF-␣ mRNA (r ϭ 0.8210, p ϭ 0.0236) correlated positively to the homeostatic model. Discussion: Overall, dSAT seems to be a distinct abdominal adipose depot supporting an independent metabolic function that may have a potential role in the development of obesity-associated complications.

Body Fat Partitioning Does Not Explain the Interethnic Variation in Insulin Sensitivity Among Asian Ethnicity: The Singapore Adults Metabolism Study

“…The DSAT depot has higher saturated lipids content compared with SSAT (21). The expression profiles of 11b-hydroxysteroid dehydrogenase-1, leptin, and resistin in DSAT are closer to VAT (22). Taken together, DSAT represents a distinct abdominal fat depot that may have pathogenic potential in the development of obesityassociated disorders.…”

Adipose tissue in obesity and obstructive sleep apnoea

“…Besides the classic distinction between visceral and subcutaneous fat, the latter can be subdivided into superficial and deep, with the deep fraction sharing many features with visceral fat [61]. Ectopic fat depots can be found in the epicardial, periadvential and perirenal regions, and in the pancreas, skeletal muscle and bone marrow [47].…”

Structural and Functional Properties of Deep Abdominal Subcutaneous Adipose Tissue Explain Its Association With Insulin Resistance and Cardiovascular Risk in Men

“…The classical abdominal adipose tissue (AT) compartmentalization into subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) has been widely studied in relation to obesityrelated complications (2)(3)(4). The anatomical distinction of SAT compartments into superficial subcutaneous adipose tissue (sSAT) and deep subcutaneous adipose tissue (dSAT), divided by Scarpa's fascia, is well documented in literature (5)(6)(7)(8)(9). A few studies have shown that dSAT is strongly related to IR in a manner nearly identical to that of VAT, while sSAT follows the pattern of lower-body SAT (1,10).…”