Brown adipose tissue – A future treatment for obesity?

Abstract

Obesity is a major public health concern: in the United Kingdom (UK) over two thirds of the population are obese or overweight, the prevalence of obesity is growing exponentially, and current treatment options have limited success – making the need for novel therapies vital. Brown adipose tissue (BAT) has the ability to safely dissipate chemical energy as heat and in 2009 was found to be active in human adults, leading to hope that its therapeutic manipulation could contribute to weight loss. This review discusses methods proposed for BAT activation and potential pitfalls in our current understanding to evaluate if BAT can be used as a future treatment for obesity. To date, ?3-adrenergic receptor (?3-AR) agonists and cold activation have been shown to be the most promising options to activate BAT. However, cold activation requires a high degree of patient cooperation and ?3-AR agonists appear non-effective long-term. Nonetheless, ?3-AR agonists are likely to be a more realistic treatment than cold activation, making our next challenge to understandand mitigate the mechanisms that inhibit BAT activation in long-term ?3-AR agonist administration. Our assumptions about BAT activation are predominately from rodent studies and based on measurements from [18F]-fl uorodeoxyglucose (18F-FDG)-positron-emission tomography and computed tomography (PET/CT) imaging, both with their respective limitations. BAT has offered huge insight into weight homeostasis, with the potential of offering prospective therapeutics for obesity and beyond. Nevertheless, before we can truly understand the real possibilities of BAT we need to further our current understanding of the physiological controls of BAT, potentially leading to more suitable therapies. The focus for future research should be to improve and standardise the methodology used to measure BAT activation, enabling larger clinical trials and better comparisons.