The recognition that certain obese patients do not exhibit unfavorable
metabolic changes, with a low risk for cardiovascular disorders, and that some
individuals with a normal weight develop metabolic complications such as insulin
resistance, gave rise to the idea that in obesity not only adipose tissue (AT) quantity
matters but also AT function, with more relevance. It is known, that impaired AT
function is caused by the interaction of genetic and environmental factors which lead to
adipocyte hypertrophy, hypoxia and a variety of stresses, including inflammatory
processes within the AT. Indeed, AT dysfunction translates into the imbalance between
pro- and anti-inflammatory adipokines produced in the adipocyte and secreted into the
systemic circulation. For instance, AT dysfunction has been characterized by decreased
release of homeostatic protective factors (such as adiponectin, omentin or vaspin) and
increased activation of stress-related pathways leading to pathological adipokine
(leptin, resistin and visfatin) formation. Systemically, AT dysfunction promotes
metabolic and vascular alterations, namely low-grade inflammation, hypercoagulability,
hypertension, dyslipidemia and insulin resistance. Thus, diagnosing AT
dysfunction is of clinical relevance, serving as a tool for stratifying risk for
cardiovascular disease or type 2 diabetes mellitus, and may guide preventive treatment
with both medication and lifestyle interventions. It is believed that in the near future, a
set of pro- and anti-inflammatory adipokines could be compiled, providing clinicians
with an 'adipokine-score' indicative of the level of AT dysfunction. In this chapter, we briefly discuss the current knowledge about the emerging biomarkers of dysfunctional
AT and their potential impact on metabolic diseases associated with obesity.
Keywords: Adipocyte, Adipokine, Adiponectin, Adipose tissue dysfunction,
Biomarker, Chemerin, Cytokine, Inflammation, Insulin resistance, Interleukin,
Leptin, Lipocalin-2, Obesity, Omentin, Retinol-binding protein 4, Resistin,
Serpin, Secreted frizzled-related protein 5, Tumor necrosis factor α, Vaspin,
Visfatin.
