White Adipose Tissue Browning: A Double-edged Sword

The study of white adipose tissue (WAT) ‘browning’ has become a ‘hot topic’ in various acute and chronic metabolic conditions, based on the idea that WAT browning might be able to facilitate weight loss and improve metabolic health. However, this view cannot be translated into all areas of medicine. Recent studies identified effects of browning associated with adverse outcomes, and as more studies are being conducted, a very different picture has emerged about WAT browning and its detrimental effect in acute and chronic hypermetabolic conditions. Therefore, the notion that browning is supposedly beneficial may be inadequate. In this review we analyze how and why browning in chronic hypermetabolic associated diseases can be detrimental and lead to adverse outcomes.

TrendsInducing ‘browning’ within white adipose tissue (WAT), that is, by increasing uncoupling protein 1 (UCP-1) expression, has attracted much interest in the field of obesity.WAT browning has several beneficial metabolic effects such as increasing energy expenditure and reducing adiposity.The unique metabolic benefits of browning in WAT have recently been overshadowed by its implication in cachexia, atherosclerosis, and hepatic steatosis during hypermetabolic conditions.WAT browning appears to be a double-edged sword, beneficial in obesity and diabetes, but detrimental in hypermetabolic conditions.Understanding the molecular mechanisms underlying browning-induced hypermetabolism may allow for the development of therapeutic approaches that attenuate or even eliminate the associated adverse metabolic effects.