Brown Adipose Tissue In Nonshivering Thermogenesis
The present findings support a role of BAT for nonshivering thermogenesis in humans with intracellular triglycerides as the main source of energy for this process, as observed in rodents. However, it remains to be demonstrated whether chronic and frequent bouts of cold exposure may contribute to increase BAT capacity and/or activity and may be a viable adjunct therapeutic strategy to other lifestyle interventions to prevent or treat obesity and its metabolic complications. It is also possible that energy substrate uptake by BAT could be substantially increased once intracellular triglyceride stores are depleted and/or BAT is fully cold adapted, as recently shown in rodents (22). Quantitative assessment of the contribution of intracellular triglyceride oxidation in BAT thermogenesis awaits further methodological developments.
In summary, the present study demonstrates that a cold-exposure stimulus designed to minimize muscle-mediated shivering thermogenesis enhances BAT oxidative metabolism as well as glucose and NEFA uptake in adult humans. The enhanced BAT activity was associated with a 1.8-fold increase in whole-body energy expenditure. We found a significant inverse relationship between BAT volume of activity and shivering and a significant increase in BAT radio density within 3 hours of cold exposure, indicating rapid reduction in BAT triglyceride content. The present results demonstrate that BAT is undoubtedly involved in nonshivering thermogenesis in humans.
Véronique Ouellet, Sébastien M. Labbé, Denis P. Blondin, Serge Phoenix, Brigitte Guérin, François Haman, Eric E. Turcotte, Denis Richard and André C. Carpentier.
Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans
J Clin Invest.
Université Laval, Quebec City, Quebec, Canada.