From fat fighter to risk factor: the zigzag trek of leptin.

Obesity is a major risk factor for a number of cardiovascular diseases, and causes cardiac and vascular disease through well-known mediators including arterial hypertension, hyperlipidemia, and type-2 diabetes. Obesity is characterized by an excess of adipose tissue, which efficiently stores energy for times of starvation. In addition, multiple reports in the last decade have underlined the importance of white adipose tissue (WAT) as an endocrine organ.1 Several peptide hormones commonly referred to as adipokines are secreted by WAT, including leptin, adipsin, acylation-stimulating protein (ASP), angiotensinogen, plasminogen activator inhibitor-1 (PAI-1), adiponectin, resistin, various cytokines including GM-CSF and G-CSF, and steroid hormones.1 Consequently, WAT peptide hormones and cytokines are involved in energy homeostasis, glucose and lipid metabolism, immune response, reproduction, and vascular homeostasis.