Fetuin-A and angiopoietins in obesity and type 2 diabetes mellitus

Although type 2 diabetes mellitus (DM) is a chronic metabolic disorder with multiple etiologies, obesity has been constantly linked with insulin resistance and manifestation of type 2 DM. In addition, obesity is associated with hypertension, dyslipidemia, and fatty liver disease and is regarded as a subclinical inflammatory condition characterized by release of pro-inflammatory mediators such as cytokines from adipose tissue. Both, type 2 DM and obesity are considered as major risks for developing micro- and macrovascular diseases. Recent studies showed that impaired circulating levels of fetuin-A, which is involved in propagating insulin resistance as well as circulating levels of angiopoietins, which are growth factors promoting angiogenesis, were observed in patients with obesity, metabolic syndrome, and type 2 DM. However, independent of type 2 DM and obesity, defective regulation of fetuin-A and angiopoietin are playing a critical role in predisposing to coronary and peripheral vascular diseases. Therefore, mechanisms linking type 2 DM and obesity with fetuin-A and angiopoietins seem to be complex and are in need of further exploration. In this review, we aimed to present a summary concerning associations of type 2 diabetes, obesity, and vascular diseases with circulating levels of angiopoietins and fetuin-A. Furthermore, we aimed to focus on roles of fetuin-A and angiopoietins and to highlight the most plausible mechanisms that might explain their associations with type 2 DM and obesity.