Sled Dogs as a Model for Brown Fat Research

Brown adipose tissue (BAT) has the unique function of burning energy to create heat through the process of non-shivering thermogenesis. Activation of BAT in humans as a means of combating obesity is an active area of research, yet reliability of methods for recognizing and monitoring activation needs further research. This study assessed the feasibility of thermal imaging for monitoring BAT activation in an animal model, Alaskan sled dogs, which have been used extensively in coldweather metabolism and nutrition research. BAT activation was monitored monthly over four months in a cohort of five sled dog puppies. A change in temperature accompanies BAT activation. Therefore thermal images of the chest area were taken pre- and post-cold exposure. Concentrations of two plasma biomarkers associated with non-shivering thermogenesis, irisin and fibroblast growth factor 21 (FGF21) were also analyzed. No significant temperature change or concentration changes in irisin or FGF21 were observed between pre-and post-cold exposures. To our knowledge this is the first study in dogs, therefore the results provide methodology strategies for future study design. Given the potential benefits of BAT activation in humans, the validation of thermal imaging as a non-invasive monitoring technique and the use of an animal model could better inform the treatment of metabolic diseases.