Understanding the molecular mechanisms underlying adipose blood vessel growth or regression opens new fundamentally insight into novel therapeutic options for the treatment of obesity and its related metabolic diseases such as type 2 diabetes and cancer. Unlike any other tissues in the body, the adipose tissue constantly experiences expansion and shrinkage throughout the adult life. Adipocytes in the white adipose tissue have the ability to switch into metabolically highly active brown-like adipocytes. Brown adipose tissue (BAT) contains significantly higher numbers of microvessels than white adipose tissue (WAT) in order to adopt the high rates of metabolism. Thus, an angiogenic phenotype has to be switched on during the transition from WAT into BAT. We have found that acclimation of mice in cold could induce transition from inguinal and epidedymal WAT into BAT by upregulation of angiogenic factor expression and down-regulations of angiogenesis inhibitors (Xue et al, Cell Metabolism, 2009). The transition from WAT into BAT is dependent on vascular endothelial growth factor (VEGF) that primarily targets on vascular endothelial cells via a tissue hypoxia-independent mechanism. VEGF blockade significantly alters adipose tissue metabolism. In another genetic model, we show similar findings that angiogenesis is crucial to mediate the transition from WAT into BAT (Xue et al, PNAS, 2008). Here we propose that the vascular tone determines the metabolic switch between WAT and BAT. Characterization of these novel angiogenic pathways may reveal new mechanisms underlying development of obesity- and metabolism-related disease complications and may define novel therapeutic targets. Thus, the benefit of this research proposal is enormous and is aimed to treat the most common and highly risk human health conditions in the modern time.