Brown and beige adipose tissues: phenotype and metabolic potential in mice and men

With the recent re-discovery of brown fat in adult humans, our outlook on adipose tissue biology has undergone a paradigm shift. While we attempt to identify, recruit and activate classic brown fat stores in humans, identification of beige/brite adipocytes has also raised the possibility of browning our white fat stores. Whether such transformation of human white fat depots can be achieved in order to enhance the whole-body oxidative potential remains to be seen. Evidence to-date, however, largely points towards a major oxidative role only for classic brown fat depots in rodents and in humans (e.g. supraclavicular fat depot). White fat stores seem to provide the main fuel for sustaining thermogenesis via lipolysis. Interestingly, molecular markers consistent with both classic brown and beige fat identity can be observed in human supraclavicular depot, thereby complicating the discussion on beige fat in humans. Here, we review the recent advances made in our understanding of brown and beige fat in humans a...