Oral Presentation Australian & New Zealand Obesity Society 2016 Annual Scientific Meeting

Invited talk: Hot and sweet: brown fat beyond thermo-regulation in humans (#4)

Paul Lee 1
  1. Garvan Institute of Medical Research, Darlinghurst, NSW, Australia

There are three kinds of fat tissue. White adipose tissue (WAT) stores energy and in excess leads to obesity. Brown adipose tissue (BAT) consumes energy and produces heat for thermo-regulation. Beige adipose tissue (BeAT) emerges within WAT during cold exposure and manifests thermogenic function comparable to BAT. Animals with high BAT/BeAT status are protected against diabetes and obesity. Recent re-discovery of thermogenic BAT in humans has brought the relation between ambient temperature, thermogenesis and systemic energy and substrate metabolism to the forefront (1).
Humans maintain core temperature through a complex neuroendocrine circuitry, coupling environmental thermal and nutritional cues to heat-producing and dissipating mechanisms. Up to 40% of resting energy expenditure contributes to thermal homeostasis maintenance. The dynamic interplay between BAT, BeAT and WAT modulates systemic energy homeostasis and highlights the presence of a previously under-appreciated thermogenic adipose axis in humans.
In addition to well-known pituitary-thyroid-adrenal axis, recently identified endocrine signals, such as FGF21 and irisin (2), orchestrate crosstalk between WAT, BAT and muscle, tuning non-shivering and shivering thermogenesis responses. Cold-activated BAT modulates systemic metabolic and endocrine milieu, and cold-induced hormones cause bioenergetics transformation sufficient to impact whole body energy and substrate balance (3), suggesting BAT may serve important physiologic functions beyond thermoregulation in humans.

  1. Lee et al. Endocr Rev. 2013;34:413-38.
  2. Lee et al. Cell Metab. 2014;19:302-9.
  3. Lee et al. Cell Metab. 2016;23:602-9.