Brown fat and obesity: the next big thing?

Abstract

Brown adipose tissue (BAT) is well recognised to have an important role in the maintenance of body temperature in animals and human neonates, its thermogenic action affected by a tissue-specific uncoupling protein; fatty acid oxidation within the numerous brown adipocyte mitochondria is rendered inefficient leading to heat, rather than adenosine triphosphate (ATP), production. BAT was believed to show rapid involution in early childhood, leaving only vestigial amounts in adults. However, recent evidence suggests that its expression in adults is far more common than previously appreciated, with a higher likelihood of detection in women and leaner individuals. It is conceivable that BAT activity might reduce the risk of developing obesity since fat stores are used for thermogenesis, and a directed enhancement of adipocyte metabolism might have value in weight reduction. However, it is as yet unclear how such manipulation of BAT might be achieved; even in animal models, the control of thermogenic activity is incompletely understood. Even so, there is still much to interest the endocrinologist in BAT, with a range of hormones affecting adipocyte activity. This may either contribute to normal physiological function, or the phenotypical presentation of states of pathological hormone excess or deficiency. Thus, the gender differences in BAT distribution may be attributable to the differential effects of male and female sex hormones, whilst BAT expansion may drive the weight loss associated with catecholamine-producing phaeochromocytomas. These observations support an important influence of the endocrine system on BAT activity and offer new potential targets in the treatment of obesity.

Effects and mechanisms of auricular vagus nerve stimulation on high-fat-diet—induced obese rats

“…Adipose metabolism is considered a noticeable studying point; the thermogenic function in brown adipose tissue (BAT) is believed to play a major role in adipose metabolism [5]. Increasing BAT activity is considered a new strategy for treating obesity.…”

Pathological Role of Adipose Tissue Dysfunction in Cardio-Metabolic Disorders

“…However, recent studies have shown that adult humans also possess active BAT. [18][19][20][21] Besides being involved in thermogenesis, BAT has been suggested to contribute significantly to systemic metabolism because of its high energy expenditure ratio. [22][23][24][25][26][27] Although BAT is now recognized as a potential regulator of systemic metabolism in persons with obesity and diabetes, 28) the molecular mechanism underlying the decline of BAT activity in obesity and its physiological implications are largely unknown.…”

Adipose tissue in obesity and obstructive sleep apnoea

“…A modest amount of brown adipose tissue (BAT) is also present in humans, its main function being heat production rather than energy storage. The peculiar anatomical and functional characteristics of BAT have been recently summarised [54][55][56].…”