This study of Tay et al. refines an algorithm to analyze thermal images capturing BAT activity under cold air exposure. In addition, this study also aims to validate the sensitivity of the whole-body calorimeter (WBC) in measuring cold-induced thermogenesis, and to subsequently correlate IRT and WBC measurements for determining BAT activity under cold air exposure. The cold air exposure was aimed to represent a realistic cold experience that free-living humans can go through, such that this cooling protocol can be used to better model the effects of BAT activation following environmental and pharmacological interventions. 

The obesity epidemic 

Obesity has become one of the main public health problems of the 21st century, although it predominates in developed countries the exponential increase in the overweight or obese population has turned this problem into a global epidemic. Despite efforts to promote lifestyle changes aimed at correcting the excessive positive energy balance, they occur in an obesogenic environment that perpetuates the vicious cycle and ultimately leads to significant morbidity and mortality associated with this condition. 

All above mentioned highlight the need of exploring new strategies to reduce obesity. It is well known that adipose tissue plays a complex role in energy balance. On the one hand white adipose tissue (WAT) acts as an energy store while brown adipose tissue (BAT) is responsible for dissipating the energy stored in the form of heat, in other words, BAT is thermogenic. The existence of functional BAT in adults opens a new line of research around the control of obesity from the manipulation of BAT. 

What are the potential therapeutic targets? 

The thermogenic capacity of BAT is mainly mediated by a protein called uncoupling protein-1 (UCP-1), which is located in the inner mitochondrial membrane. BAT-mediated thermogenesis can be stimulated by exogenous and endogenous mechanisms such as cold exposure or capsaicin / capsainoid consumption. In order to measure these effects the study made use of the whole body indirect calorimetry chambers of Maastricht Instruments.  

The identification of possible therapeutic targets and the possibility of controlling the thermogenesis process (and therefore energy expenditure) have increased interest in pharmacological, nutritional and environmental interventions that lead to an increase in either the activity or the volume of BAT. 

How do physics and medicine converge? 

As we previously mentioned, it is a large-scale problem and therefore merits experimental designs that can be applied at the population level, with easily reproducible results and of course safe for the study subjects. It is at this point where physics and medicine converge. Infrared thermography (IRT) allows measurements of the heat released at specific BAT sites. Since heat is the end product of UCP-1 mediated thermogenesis it is a potential indirect marker of BAT activity. In addition to allowing indirect measurement of BAT activity, infrared thermography has all the virtues that a technique requires to be applied on a massive scale in clinical research. It is an inexpensive, innocuous, reliable, non-invasive technique that allows data (in the form of thermal images and videos) to be obtained quickly and easily. 

Why using infrared thermography and thermogenesis in the study of BAT? 

The study of BAT´s activity determined by infrared thermography and thermogenesis constitutes a new line of research that makes use of techniques provided by physics and that is based on relatively new knowledge of adipose tissue functions. Using this technique, it is possible to address obesity from various points of view and develop new therapies that allow us to fight the obesity epidemic more effectively. Either simulating the conditions of free-living humans or addressing the behavior of BAT during different levels of physical exercise, infrared thermography is positioned as a very appropriate technique for clinical studies related to obesity. 

How can we help you with your research? 

Maastricht Instruments creates equipment in the field for indirect calorimetry measurements. We provide support for studies, research and measurements alongside our indirect calorimetry products.  

Consult us about our indirect calorimetry metabolic  cart,  whole room calorimeter  systems or  accelerometry  add-ons. Please  contact us or find more information on our information pages. 

Article reference 

Brown fat activity determined by infrared thermography and thermogenesis measurement using whole body calorimetry (Tay SH et al., 2020) 

Keywords: Brown adipose tissue, Infrared thermography, Calorimetry, Thermogenesis, Automation 

DOI-Link: 10.33549/physiolres.934190