Establishing a non-invasive protocol for estimating brown adipose tissue volume

Abstract

Background Brown adipose tissue has emerged as an attractive therapeutic target for anti-obesity strategies. Currently, non-invasive techniques in the assessment of brown adipose tissue are limited, however, the use of infrared thermography imaging has gained recent recognition as a potential method. Objectives To 1) optimise a non-invasive, reproducible protocol for the assessment of skin temperature overlying the supraclavicular regions in human participants using infrared thermography imaging, 2) assess the changes in energy expenditure using a similar protocol, and 3) assess the relationship between energy expenditure and supraclavicular skin temperature change. Study Design Infrared thermography imaging was used in healthy volunteer participants to develop a protocol involving a cold stimulus for inducing an increase in the skin temperature of the supraclavicular region. The protocol was then optimised by assessing the detection in skin temperature under different conditions. The established protocol (submersion of the hand and forearm in water at 16oC) was used to assess the reproducibility of supraclavicular skin temperature change between repeated measures. A similar cold stimulus (submersion of the feet and calves in water at 16oC) was used to assess the elevation in energy expenditure. The relationship between skin temperature change, resting energy expenditure, and cold-induced elevations in energy expenditure were explored. Results We demonstrated increases in the skin temperature of the supraclavicular region using the established protocol. Furthermore, repeated measurements using this protocol yielded reproducible results. Increases in energy expenditure following cold stimulus exposure were also demonstrated. However, we were unable to show a relationship between cold-induced increases in supraclavicular skin temperature and cold-induced increases in energy expenditure or resting energy expenditure at thermoneutrality. Conclusion The cold-induced thermogenesis in the supraclavicular region can be consistently quantified with infrared thermography imaging. These findings suggest the potential use of infrared thermography imaging as a non-invasive technique in the assessment of brown adipose tissue function in humans. This technique may also be used in conjunction with the assessment of energy metabolism to further understand the role of brown adipose tissue thermogenesis in human energy balance and its potential exploitation in the prevention and treatment strategies of obesity.