Diabetes as a complication of adipose tissue dysfunction. Is there a role for potential new biomarkers?

Increasing incidence of type 2 diabetes is a major health problem of the modern world and requires new diagnostic tools to assess early metabolic disorders, particularly insulin resistance. The link between obesity, inflammation and insulin resistance indicates the important secretory role of adipose tissue. Proinflammatory factors (cytokines, adipokines) produced by enlarged adipose tissue are related to impaired glucose metabolism. Adipokines act as paracrine factors in adipose tissue and as endocrine hormones in the liver, muscles and central nervous system. Novel adipokines secreted from adipocytes such as retinol binding protein-4 (RBP-4), vaspin, omentin, chemerin, fibroblast growth factor 21 (FGF21), adipocyte fatty acid-binding protein (A-FABP) and dipeptidyl peptidase 4 (DPP4) demonstrate pleiotropic activity and their insulin-sensitizing or enhancing insulin resistance properties have not been clearly confirmed yet. In spite of the lack of standardized automated assay methods currently available for these novel biomarkers, promising results from several studies emphasize that they might potentially be useful prognostic factors for diabetes and its complications, especially in individuals without the typical symptoms of metabolic syndrome.