Fat tissues, the brite and the dark sides

Fat tissue is well known for its capacity to store energy and its detrimental role in obesity and metaflammation. However, humans possess different types of fat that have different functions in physiology and metabolic diseases. Apart from white adipose tissue (WAT), the body’s main energy storage, there is also brown adipose tissue (BAT) that dissipates energy as a defense against cold and maintains energy balance for the whole body. BAT is present not only in newborns but also in adult humans and its mass correlates with leanness. Moreover, “brown-like” adipocytes have been detected in human WAT. These “brown-in-white” (brite) or beige cells can be induced by cold and a broad spectrum of pharmacological substances and, therefore, they are also known as “inducible brown adipocytes.” Activation of brown and/or brite adipocytes reduces metabolic diseases, at least in murine models of obesity. Thus, brown/brite adipocytes represent the “brite” side of fat and are potential targets for novel therapeutic approaches for treatment of obesity and obesity-associated diseases.