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Nature Reviews. Molecular Cell Biology Nov 2016Brown and beige adipocytes expend chemical energy to produce heat and are therefore important in regulating body temperature and body weight. Brown adipocytes develop in... (Review)
Review
Brown and beige adipocytes expend chemical energy to produce heat and are therefore important in regulating body temperature and body weight. Brown adipocytes develop in discrete and relatively homogenous depots of brown adipose tissue, whereas beige adipocytes are induced to develop in white adipose tissue in response to certain stimuli - notably, exposure to cold. Fate-mapping analyses have identified progenitor populations that give rise to brown and beige fat cells, and have revealed unanticipated cell-lineage relationships between vascular smooth muscle cells and beige adipocytes, and between skeletal muscle cells and brown fat. In addition, non-adipocyte cells in adipose tissue, including neurons, blood vessel-associated cells and immune cells, have crucial roles in regulating the differentiation and function of brown and beige fat.
Topics: Adipocytes; Adipose Tissue, Beige; Adipose Tissue, Brown; Animals; Cell Communication; Cell Differentiation; Energy Metabolism; Humans; Obesity; Thermogenesis
PubMed: 27552974
DOI: 10.1038/nrm.2016.96 -
Cell Reports. Medicine Oct 2021The Scandinavian winter-swimming culture combines brief dips in cold water with hot sauna sessions, with conceivable effects on body temperature. We study thermogenic...
The Scandinavian winter-swimming culture combines brief dips in cold water with hot sauna sessions, with conceivable effects on body temperature. We study thermogenic brown adipose tissue (BAT) in experienced winter-swimming men performing this activity 2-3 times per week. Our data suggest a lower thermal comfort state in the winter swimmers compared with controls, with a lower core temperature and absence of BAT activity. In response to cold, we observe greater increases in cold-induced thermogenesis and supraclavicular skin temperature in the winter swimmers, whereas BAT glucose uptake and muscle activity increase similarly to those of the controls. All subjects demonstrate nocturnal reduction in supraclavicular skin temperature, whereas a distinct peak occurs at 4:30-5:30 a.m. in the winter swimmers. Our data leverage understanding of BAT in adult human thermoregulation, suggest both heat and cold acclimation in winter swimmers, and propose winter swimming as a potential strategy for increasing energy expenditure.
Topics: Adipose Tissue, Brown; Adult; Circadian Rhythm; Cold Temperature; Hormones; Humans; Magnetic Resonance Imaging; Male; Perception; Positron-Emission Tomography; Seasons; Skin Temperature; Swimming; Thermogenesis; Thermography; Young Adult
PubMed: 34755128
DOI: 10.1016/j.xcrm.2021.100408 -
Nutrients Sep 2023Brown and beige adipocytes are renowned for their unique ability to generate heat through a mechanism known as thermogenesis. This process can be induced by exposure to... (Review)
Review
Brown and beige adipocytes are renowned for their unique ability to generate heat through a mechanism known as thermogenesis. This process can be induced by exposure to cold, hormonal signals, drugs, and dietary factors. The activation of these thermogenic adipocytes holds promise for improving glucose metabolism, reducing fat accumulation, and enhancing insulin sensitivity. However, the translation of preclinical findings into effective clinical therapies poses challenges, warranting further research to identify the molecular mechanisms underlying the differentiation and function of brown and beige adipocytes. Consequently, research has focused on the development of drugs, such as mirabegron, ephedrine, and thyroid hormone, that mimic the effects of cold exposure to activate brown fat activity. Additionally, nutritional interventions have been explored as an alternative approach to minimize potential side effects. Brown fat and beige fat have emerged as promising targets for addressing nutritional imbalances, with the potential to develop strategies for mitigating the impact of metabolic diseases. Understanding the influence of nutritional factors on brown fat activity can facilitate the development of strategies to promote its activation and mitigate metabolic disorders.
Topics: Adipose Tissue, Brown; Nutritional Status; Adipocytes; Adipocytes, Beige; Adipose Tissue, Beige
PubMed: 37764855
DOI: 10.3390/nu15184072 -
Diabetes & Metabolism Journal Nov 2021Brown adipose tissue (BAT) is a specialized tissue for nonshivering thermogenesis to dissipate energy as heat. Although BAT research has long been limited mostly in... (Review)
Review
Brown adipose tissue (BAT) is a specialized tissue for nonshivering thermogenesis to dissipate energy as heat. Although BAT research has long been limited mostly in small rodents, the rediscovery of metabolically active BAT in adult humans has dramatically promoted the translational studies on BAT in health and diseases. Moreover, several remarkable advancements have been made in brown fat biology over the past decade: The molecular and functional analyses of inducible thermogenic adipocytes (socalled beige adipocytes) arising from a developmentally different lineage from classical brown adipocytes have been accelerated. In addition to a well-established thermogenic activity of uncoupling protein 1 (UCP1), several alternative thermogenic mechanisms have been discovered, particularly in beige adipocytes. It has become clear that BAT influences other peripheral tissues and controls their functions and systemic homeostasis of energy and metabolic substrates, suggesting BAT as a metabolic regulator, other than for thermogenesis. This notion is supported by discovering that various paracrine and endocrine factors are secreted from BAT. We review the current understanding of BAT pathophysiology, particularly focusing on its role as a metabolic regulator in small rodents and also in humans.
Topics: Adipocytes, Brown; Adipose Tissue, Brown; Energy Metabolism; Thermogenesis; Uncoupling Protein 1
PubMed: 34176254
DOI: 10.4093/dmj.2020.0291 -
Biochimica Et Biophysica Acta.... Jan 2019Brown adipose tissue (BAT) dissipates energy as heat and its activity correlates with leanness in human adults. Understanding the mechanisms behind the activation of BAT... (Review)
Review
Brown adipose tissue (BAT) dissipates energy as heat and its activity correlates with leanness in human adults. Understanding the mechanisms behind the activation of BAT and the process of "browning", i.e. the appearance of inducible brown adipocytes called beige or brite (brown-in-white) cells in white adipose tissue (WAT), is of great interest for developing novel therapies to combat obesity. MicroRNAs (miRNAs) are small transcriptional regulators that control gene expression in a variety of tissues, including WAT and BAT. Recently, miRNAs were reported to regulate browning. Nevertheless, further studies are needed to fully understand the miRNA networks that are involved in the control of brown and beige/brite adipocytes. Particularly, most miRNAs have so far been studied in mice, underlining the importance of additional human studies. In this review, we focus on the regulation of brown fat by miRNAs including their role in promoting or inhibiting the browning process. In recent years, RNA-based therapeutical approaches have entered clinical trials for treatment of other diseases, thus miRNAs could potentially be used to enhance brown and beige fat mass and activity as novel therapies against overweight and its complications.
Topics: Adipogenesis; Adipose Tissue, Beige; Adipose Tissue, Brown; Animals; Humans; MicroRNAs
PubMed: 29758288
DOI: 10.1016/j.bbalip.2018.05.003 -
Frontiers in Endocrinology 2020Obesity is characterized by a state of chronic inflammation in adipose tissue mediated by the secretion of a range of inflammatory cytokines. In comparison to WAT,... (Review)
Review
Obesity is characterized by a state of chronic inflammation in adipose tissue mediated by the secretion of a range of inflammatory cytokines. In comparison to WAT, relatively little is known about the inflammatory status of brown adipose tissue (BAT) in physiology and pathophysiology. Because BAT and brown/beige adipocytes are specialized in energy expenditure they have protective roles against obesity and associated metabolic diseases. BAT appears to be is less susceptible to developing inflammation than WAT. However, there is increasing evidence that inflammation directly alters the thermogenic activity of brown fat by impairing its capacity for energy expenditure and glucose uptake. The inflammatory microenvironment can be affected by cytokines secreted by immune cells as well as by the brown adipocytes themselves. Therefore, pro-inflammatory signals represent an important component of the thermogenic potential of brown and beige adipocytes and may contribute their dysfunction in obesity.
Topics: Adipogenesis; Adipose Tissue, Brown; Animals; Humans; Inflammation; Obesity; Signal Transduction; Thermogenesis
PubMed: 32265845
DOI: 10.3389/fendo.2020.00156 -
Science Signaling Dec 2022The multilocular phenotype of brown adipose tissue is determined by an ER-lipid droplet anchoring protein.
The multilocular phenotype of brown adipose tissue is determined by an ER-lipid droplet anchoring protein.
Topics: Adipose Tissue, Brown; Proteins; Lipid Droplets
PubMed: 36538591
DOI: 10.1126/scisignal.adg3025 -
Hormone Molecular Biology and Clinical... Jul 2014The growing understanding of adipose tissue as an important endocrine organ with multiple metabolic functions has directed the attention to the (patho)physiology of... (Review)
Review
The growing understanding of adipose tissue as an important endocrine organ with multiple metabolic functions has directed the attention to the (patho)physiology of distinct fat depots. Brown adipose tissue (BAT), in contrast to bona fide white fat, can dissipate significant amounts of chemical energy through uncoupled respiration and heat production (thermogenesis). This process is mediated by the major thermogenic factor uncoupling protein-1 and can be activated by certain stimuli, such as cold exposure, adrenergic compounds or genetic alterations. White adipose tissue (WAT) depots, however, also possess the capacity to acquire brown fat characteristics in response to thermogenic stimuli. The induction of a BAT-like cellular and molecular program in WAT has recently been termed "browning" or "beiging". Promotion of BAT activity or the browning of WAT is associated with in vivo cold tolerance, increased energy expenditure, and protection against obesity and type 2 diabetes. These preclinical observations have gained additional significance with the recent discovery that active BAT is present in adult humans and can be detected by 18fluor-deoxy-glucose positron emission tomography coupled with computed tomography. As in rodents, human BAT can be activated by cold exposure and is associated with increased energy turnover and lower body fat mass. Despite the tremendous progress in brown fat research in recent years, pharmacological concepts to harness BAT function therapeutically are currently still lacking.
Topics: Adipocytes; Adipose Tissue, Brown; Adipose Tissue, White; Animals; Diabetes Mellitus, Type 2; Energy Metabolism; Humans; Ion Channels; Mitochondrial Proteins; Obesity; Thermogenesis; Transcription, Genetic; Uncoupling Protein 1
PubMed: 25390014
DOI: 10.1515/hmbci-2014-0022 -
Journal of Magnetic Resonance Imaging :... Nov 2021Metabolic syndrome is presently becoming a global health concern. Brown adipose tissue (BAT) has the potential for managing the risk factors of metabolic syndrome by... (Review)
Review
Metabolic syndrome is presently becoming a global health concern. Brown adipose tissue (BAT) has the potential for managing the risk factors of metabolic syndrome by adjusting plasma lipids and glucose. Magnetic resonance imaging (MRI) is a noninvasive and radiation-free imaging modality for BAT research and clinical applications in both animals and humans. In the past decade, MRI technologies for detecting and characterizing BAT have developed rapidly, with progress in MRI sequencing and the emerging understanding of BAT. In this review, we focus on the main MRI methods for BAT including currently used imaging techniques and new methods and their implications for the symptoms and complications of metabolic syndrome. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 2.
Topics: Adipose Tissue, Brown; Animals; Humans; Magnetic Resonance Imaging; Metabolic Syndrome; Risk Factors
PubMed: 33047448
DOI: 10.1002/jmri.27340 -
Trends in Endocrinology and Metabolism:... May 2015Brown fat is highly active in fuel oxidation and dissipates chemical energy through uncoupling protein (UCP)1-mediated heat production. Activation of brown fat leads to... (Review)
Review
Brown fat is highly active in fuel oxidation and dissipates chemical energy through uncoupling protein (UCP)1-mediated heat production. Activation of brown fat leads to increased energy expenditure, reduced adiposity, and lower plasma glucose and lipid levels, thus contributing to better homeostasis. Uncoupled respiration and thermogenesis have been considered to be responsible for the metabolic benefits of brown adipose tissue. Recent studies have demonstrated that brown adipocytes also secrete factors that act locally and systemically to influence fuel and energy metabolism. This review discusses the evidence supporting a thermogenesis-independent role of brown fat, particularly through its release of secreted factors, and their implications in physiology and therapeutic development.
Topics: Adipocytes, Brown; Adiponectin; Adipose Tissue, Brown; Animals; Bone Morphogenetic Proteins; Energy Metabolism; Fibroblast Growth Factors; Homeostasis; Humans; Ion Channels; Mitochondrial Proteins; Nerve Growth Factor; Neuregulins; Obesity; Thermogenesis; Uncoupling Protein 1; Vascular Endothelial Growth Factor A
PubMed: 25843910
DOI: 10.1016/j.tem.2015.03.002