Central obesity as a clinical marker of adiposopathy; increased visceral adiposity as a surrogate marker for global fat dysfunction

Abstract

Purpose of reviewSubcutaneous adipose tissue (SAT) is often described as ‘protective’. Visceral adipose tissue (VAT) is often described as ‘pathologic’. However, both SAT and VAT have protective and pathologic potential, with interdependent biologic functions.Recent findingsMost of the body's (excess) energy is stored as fat in SAT. If during positive caloric balance, SAT does not undergo adequate adipogenesis, then excess energy may result in adipocyte hypertrophy, leading to hypoxia, immunopathies, and endocrinopathies. Energy overflow may promote accumulation of pericardial fat, perivascular fat, and myocardial fat, which may directly contribute to atherosclerotic cardiovascular disease (CVD). Lipotoxic free fatty acid delivery to nonadipose body organs (e.g. liver, muscle, and pancreas) may indirectly contribute to CVD by promoting the most common metabolic disorders encountered in clinical practice (e.g. high blood sugars, high blood pressure, and dyslipidaemia), all major CVD risk factors. Finally, SAT energy overflow may increase VAT accumulation, which is also associated with increased risk of metabolic diseases and CVD.SummaryIncreased VAT is a surrogate marker for SAT dysfunction which increases waist circumference, reflecting a shared pathologic process leading to the pathogenic fat accumulation of other fat depots and fatty infiltration of nonadipose body organs. Central obesity is a clinical marker for adiposopathy.

Obesity phenotypes: normal-weight individuals with metabolic disorders versus metabolically healthy obese

“…However, an imbalance of energy may also lead to fat accumulation in ectopic depots as visceral adipose tissue, surrounding the heart and vasculature [19,22].…”

“…Generally, the risk of metabolic syndrome is lower when body fat is stored in the peripheral part of the body [13,[19][20][21]. Visceral adipose tissue (VAT) is stored in the abdominal cavity and surrounds internal organs, while subcutaneous adipose tissue is mainly located peripherally (Fig.…”

“…Thus, it is crucial to evaluate the regional distribution of fat and ectopic fat depots. The content of visceral and subcutaneous adipose tissue seems to be the main issue to explain the metabolic abnormalities in individuals representing various obesity phenotypes, mainly in the context of secretion of different adipokines and other bioactive substances [14,19].…”

“…The excess of visceral fat supports pathological vascular changes by secretion of pro-inflammatory and pro-atherosclerotic mediators, such as interleukin 6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), and glucocorticoids, which account for the development of cardiovascular diseases such as coronary artery disease and cardiac dysfunction [19][20][21]23]. It has also been observed that increased concentrations of C-reactive protein (CRP), tumour necrosis factor [19,21]. Greater insulin resistance has been observed in patients with visceral fat obesity.…”

“…Visceral adipose tissue (VAT) is stored in the abdominal cavity and surrounds internal organs, while subcutaneous adipose tissue is mainly located peripherally (Fig. 1) [13,19].…”