Three years with adult human brown adipose tissue (original) (raw)

Identification and Importance of Brown Adipose Tissue in Adult Humans

New England Journal of Medicine, 2009

BACKGROUND-Obesity results from an imbalance between energy intake and expenditure. In rodents and newborn humans, brown adipose tissue helps regulate energy expenditure by thermogenesis mediated by the expression of uncoupling protein 1 (UCP1), but brown adipose tissue has been considered to have no physiologic relevance in adult humans.

Recent advances in the detection of brown adipose tissue in adult humans: a review

Clinical science (London, England : 1979), 2018

The activation of brown adipose tissue (BAT) is associated with reductions in circulating lipids and glucose in rodents and contributes to energy expenditure in humans indicating the potential therapeutic importance of targetting this tissue for the treatment of a variety of metabolic disorders. In order to evaluate the therapeutic potential of human BAT, a variety of methodologies for assessing the volume and metabolic activity of BAT are utilized. Cold exposure is often utilized to increase BAT activity but inconsistencies in the characteristics of the exposure protocols make it challenging to compare findings. The metabolic activity of BAT in response to cold exposure has most commonly been measured by static positron emission tomography of F-fluorodeoxyglucose in combination with computed tomography (F-FDG PET-CT) imaging, but recent studies suggest that under some conditions this may not always reflect BAT thermogenic activity. Therefore, recent studies have used alternative po...

Unexpected evidence for active brown adipose tissue in adult humans

AJP: Endocrinology and Metabolism, 2007

The contention that brown adipose tissue is absent in adult man has meant that processes attributed to brown adipose tissue in experimental animals (mainly rodents) -i.e. classical nonshivering thermogenesis, adaptive adrenergic thermogenesis, diet-induced thermogenesis, anti-obesity -should be either absent or attributed to alternative (unknown) mechanisms in man.

Brown adipose tissue: what have we learned since its recent identification in human adults

Arquivos Brasileiros de Endocrinologia & Metabologia, 2014

Brown adipose tissue, an essential organ for thermoregulation in small and hibernating mammals due to its mitochondrial uncoupling capacity, was until recently considered to be present in humans only in newborns. The identification of brown adipose tissue in adult humans since the development and use of positron emission tomography marked with 18-fluorodeoxyglucose (PET-FDG) has raised a series of doubts and questions about its real importance in our metabolism. In this review, we will discuss what we have learnt since its identification in humans as well as both new and old concepts, some of which have been marginalized for decades, such as diet-induced thermogenesis. Arq Bras Endocrinol Metab. 2014;58(9):889-99

Characterizing Active and Inactive Brown Adipose Tissue in Adult Humans Using PET-CT and MR Imaging

American journal of physiology. Endocrinology and metabolism, 2016

Activated brown adipose tissue (BAT) plays an important role in thermogenesis and whole-body metabolism in mammals. Positron emission tomography (PET)-computed tomography (CT) imaging has identified depots of BAT in adult humans, igniting scientific interest. The purpose of this present study is to characterize both active and inactive supraclavicular BAT in adults, and compare the values to those of subcutaneous white adipose tissue (WAT). We obtained (18)F-fluorodeoxyglucose ((18)F-FDG) PET-CT and magnetic resonance imaging (MRI) scans of 25 healthy adults. Unlike (18)F-FDG PET, which can only detect active BAT, MRI is capable of detecting both active and inactive BAT. The MRI derived fat-signal fraction (FSF) of active BAT was significantly lower than inactive BAT (mean ± SD): 60.2 ± 7.6% vs. 62.4 ± 6.8%, respectively. This change in tissue morphology was also reflected as a significant increase in Hounsfield Units (HU): -69.4 ± 11.5 HU vs. -74.5 ± 9.7 HU, respectively. Additiona...

Brown Adipose Tissue - role in metabolic disorders

IMC Journal of Medical Science, 2019

Brown adipose tissue, a thermogenic organ, previously thought to be present in only small mammals and children has recently been identified in adult humans. Located primarily in the supraclavicular and cervical area, it produces heat by uncoupling oxidative phosphorylation due to the unique presence of uncoupling protein 1 by a process called nonshivering thermogenesis. BAT activity depends on many factors including age, sex, adiposity and outdoor temperature. Positron-emission tomography using 18F-fluorodeoxyglucose and computed tomography (18F-FDG PET–CT), magnetic resonance imaging (MRI) and thermal imaging (IRT) are among several methods used to detect BAT in humans. The importance of BAT is due to its role in whole body energy expenditure and fuel metabolism. Thus it is postulated that it may be useful in the treatment of metabolic diseases. However, there are still many unanswered questions to the clinical usefulness of this novel tissue. IMC J Med Sci 2019; 13(1): 002

High prevalence of brown adipose tissue in adult humans

Journal of Clinical …, 2011

Context: Positron emission tomography (PET)-computed tomography (CT) has identified metabolically active supraclavicular fat in adult humans based on uptake of labeled glucose and confirmed to be brown adipose tissue (BAT) histologically. However, ...

Mapping of human brown adipose tissue in lean and obese young men

Proceedings of the National Academy of Sciences of the United States of America, 2017

Human brown adipose tissue (BAT) can be activated to increase glucose uptake and energy expenditure, making it a potential target for treating obesity and metabolic disease. Data on the functional and anatomic characteristics of BAT are limited, however. In 20 healthy young men [12 lean, mean body mass index (BMI) 23.2 ± 1.9 kg/m(2); 8 obese, BMI 34.8 ± 3.3 kg/m(2)] after 5 h of tolerable cold exposure, we measured BAT volume and activity by (18)F-labeled fluorodeoxyglucose positron emission tomography/computerized tomography (PET/CT). Obese men had less activated BAT than lean men (mean, 130 vs. 334 mL) but more fat in BAT-containing depots (mean, 1,646 vs. 855 mL) with a wide range (0.1-71%) in the ratio of activated BAT to inactive fat between individuals. Six anatomic regions had activated BAT-cervical, supraclavicular, axillary, mediastinal, paraspinal, and abdominal-with 67 ± 20% of all activated BAT concentrated in a continuous fascial layer comprising the first three depots ...

Brown Adipose Tissue in Humans

Methods in Enzymology, 2014

Research with the aim to translate findings of the beneficial effects induced by brown adipose tissue (BAT) on metabolism, as seen in various non-human experimental systems to also include human metabolism requires tools that accurately measure how BAT influences human metabolism. This review sets out to discuss such techniques, how they can be used, what they can measure and also some of their limitations. The focus is on detection and functional analysis of human BAT and how this can be facilitated by applying advanced imaging technology such as: PET (Positron Emission Tomography), MRI (Magnetic Resonance Imaging), and DECT (Dual Energy Computed Tomography).

Brown Adipose Tissue and Seasonal Variation in Humans

Diabetes, 2009

OBJECTIVE Brown adipose tissue (BAT) is present in adult humans where it may be important in the prevention of obesity, although the main factors regulating its abundance are not well established. BAT demonstrates seasonal variation relating to ambient temperature and photoperiod in mammals. The objective of our study was therefore to determine whether seasonal variation in BAT activity in humans was more closely related to the prevailing photoperiod or temperature. RESEARCH DESIGN AND METHODS We studied 3,614 consecutive patients who underwent positron emission tomography followed by computed tomography scans. The presence and location of BAT depots were documented and correlated with monthly changes in photoperiod and ambient temperature. RESULTS BAT activity was demonstrated in 167 (4.6%) scans. BAT was demonstrated in 52/724 scans (7.2%) in winter compared with 27/1,067 (2.5%) in summer months (P < 0.00001, χ2 test). Monthly changes in the occurrence of BAT were more closely ...