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Rachid A, Chen B, Zhu G. A preliminary study on the effect of renal function on the metabolism of 18F-FDG in the human cerebellum. Quant Imaging Med Surg 2023; 13:5034-5042. [PMID: 37581043 PMCID: PMC10423388 DOI: 10.21037/qims-22-917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/12/2023] [Indexed: 08/16/2023]
Abstract
Background The cerebellum is less affected by normal aging or neurodegenerative diseases, the aim of this paper is to investigate the effect of renal function status on uptake of 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) in human cerebellum based on independent creatinine (CRE) or blood urea nitrogen (BUN) levels. Methods A total of 253 patients who underwent 18F-FDG PET/CT scans were included. The patients were divided into groups according to renal function status: 201 patients with normal renal function, 16 patients with increase CRE, 36 patients with decrease CRE, and 31 patients with abnormal BUN. The maximum standardized uptake values were obtained in regions of interest (ROIs) for multiple tissue types (right cerebellum, right lobe of liver, right lung, bone marrow and psoas muscle at the level of the fourth lumbar vertebra). Moreover, the selected normal CRE groups were pair-matched with CRE decrease group with respect to age, sex, body mass index and glucose, respectively. Results Among 253 patients who met the inclusion/exclusion criteria, the final analysis included 967 ROIs (244 cerebellum, 191 lungs, 230 muscles, 145 bone marrow, and 157 liver) from 18F-FDG PET/CT scans. Among patients grouped by CRE or BUN levels, the uptake of 18F-FDG by cerebellum was significantly decreased in patients with CRE decrease level (P=0.001). There were no statistically significant differences between the other groups. Matched-pair analysis indicated there were no significant changes in outcomes between the CRE decrease group and the age-, sex-, BMI-, and glucose-matched controls compared to pre-matching. Conclusions In patients with normal renal function and reduced CRE concentration, decrease cerebellar glucose metabolism was observed; however, no abnormal uptake of 18F-FDG was found in the cerebellum and other normal tissues of patients with impaired renal function. Consequently, in the study of cerebellar 18F-FDG metabolism, it may be necessary to consider the influence of blood CRE level.
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Affiliation(s)
- Abdoul Rachid
- Department of Nuclear Medicine, First Affiliated Hospital, Dalian Medical University, Dalian, China
- College of International Education, Dalian Medical University, Dalian, China
| | - Bo Chen
- Department of Nuclear Medicine, First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Guangwen Zhu
- Department of Nuclear Medicine, First Affiliated Hospital, Dalian Medical University, Dalian, China
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Civelek E, Ozen G. The biological actions of prostanoids in adipose tissue in physiological and pathophysiological conditions. Prostaglandins Leukot Essent Fatty Acids 2022; 186:102508. [PMID: 36270150 DOI: 10.1016/j.plefa.2022.102508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/29/2022] [Accepted: 10/06/2022] [Indexed: 12/29/2022]
Abstract
Adipose tissue has been established as an endocrine organ that plays an important role in maintaining metabolic homeostasis. Adipose tissue releases several bioactive molecules called adipokines. Inflammation, dysregulation of adipokine synthesis, and secretion are observed in obesity and related diseases and cause adipose tissue dysfunction. Prostanoids, belonging to the eicosanoid family of lipid mediators, can be synthesized in adipose tissue and play a critical role in adipose tissue biology. In this review, we summarized the current knowledge regarding the interaction of prostanoids with adipokines, the expression of prostanoid receptors, and prostanoid synthase enzymes in adipose tissues in health and disease. Furthermore, the involvement of prostanoids in the physiological function or dysfunction of adipose tissue including inflammation, lipolysis, adipogenesis, thermogenesis, browning of adipocytes, and vascular tone regulation was also discussed by examining studies using pharmacological approaches or genetically modified animals for prostanoid receptors/synthase enzymes. Overall, the present review provides a perspective on the evidence from literature regarding the biological effects of prostanoids in adipose tissue. Among prostanoids, prostaglandin E2 (PGE2) is prominent in regards to its substantial role in both adipose tissue physiology and pathophysiology. Targeting prostanoids may serve as a potential therapeutic strategy for preventing or treating obesity and related diseases.
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Affiliation(s)
- Erkan Civelek
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Gulsev Ozen
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey.
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Crandall J, Fraum TJ, Wahl RL. Brown adipose tissue: a protective mechanism in "pre-prediabetes"? J Nucl Med 2022; 63:1433-1440. [PMID: 35393347 DOI: 10.2967/jnumed.121.263357] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/21/2022] [Indexed: 11/16/2022] Open
Abstract
Brown adipose tissue (BAT) is present in a significant number of adult humans and has been postulated to exert beneficial metabolic effects. Lean, non-diabetic patients undergoing clinical positron emission tomography (PET)/computed tomography (CT) imaging are more likely to exhibit incidental BAT activation. The aim of this study was to assess metabolic changes associated with the cold-activation of BAT and to compare baseline blood metabolites in participants with varying amounts of active BAT. Methods: Serum blood samples were collected from healthy adult volunteers (body mass index 18.0-25.0 and age≤35 years) before and after 2 h cold exposure. 18F-flurodeoxyglucose (FDG) PET/CT imaging was performed immediately following cold exposure. Activated BAT was segmented and fasting glucose, insulin, lipid, and other blood metabolite levels were correlated with volume and intensity of active BAT. Using a median cutoff, subjects were classified as BATHIGH or BATLOW. Results: A higher volume of activated BAT was associated with significantly higher pre-cooling glucose and insulin levels (P<0.001 for each). Pre-cooling thyroid stimulating hormone (TSH) and triglyceride levels were significantly higher in the BATHIGH than in the BATLOW group (P = 0.002 and P<0.001, respectively). Triglyceride levels tended to increase over the cooling period in both BAT groups, but increased significantly more in the BATHIGH group (15.7±13.2 md/dl; P<0.001) than in the BATLOW group (4.5±12.2 mg/dl; P = 0.061). Conclusion: These findings may indicate that BAT is recruited to counteract incipient "pre-prediabetic" states, potentially serving as a first-line protective mechanism against very early metabolic or hormonal variations.
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Crandall JP, Wahl RL. Perspectives on Brown Adipose Tissue Imaging: Insights from Preclinical and Clinical Observations from the Last and Current Century. J Nucl Med 2021; 62:34S-43S. [PMID: 34230071 DOI: 10.2967/jnumed.120.246991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Brown adipose tissue (BAT) was first described in the 16th century, but until late last century had mainly been considered a tissue with the function of nonshivering thermogenesis, maintaining body temperature in key organs in newborns who have high body surface areas relative to their weight and thus marked radiative heat loss. BAT was believed to have substantially disappeared by adulthood. Molecular imaging with 18F-FDG PET and PET combined with CT, as well as imaging with 131I-metaiodobenzylguanidine (MIBG) beginning late last century have shown BAT to be present and active well into adulthood. This review highlights key aspects of BAT biology, early empiric observations misidentifying BAT, pitfalls in image interpretation, and methods to intentionally reduce BAT uptake, and outlines multiple imaging methods used to identify BAT in vivo. The therapeutic potential of increasing the amount or activity of BAT for weight loss and improvement of glucose and lipid profiles is highlighted as a major opportunity. Molecular imaging can help dissect the physiology of this complex dynamic tissue and offers the potential for addressing challenges separating "active BAT" from "total BAT." Research in BAT has grown extensively, and 18F-FDG PET is the key imaging procedure against which all other BAT imaging methods must be compared. Given the multiple functions of BAT, it is reasonable to consider it a previously unrecognized endocrine tissue and thus an appropriate topic for review in this supplement to The Journal of Nuclear Medicine.
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Affiliation(s)
- John P Crandall
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Richard L Wahl
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
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5
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Wang H, Wang M, Chansaenpak K, Liu Y, Yuan H, Xie J, Yin H, Branca RT, Li Z, Wu Z. A Novel PET Probe for Brown Adipose Tissue Imaging in Rodents. Mol Imaging Biol 2021; 22:675-684. [PMID: 31520279 DOI: 10.1007/s11307-019-01426-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Brown adipose tissue (BAT) has emerged as a promising target to counteract obesity and its associated metabolic disorders. However, the detection of this tissue remains one of the major roadblocks. PROCEDURES In this study, we assess the use of BODIPY 1 as a positron emission tomography (PET) imaging agent to image BAT depots in vivo in two mouse phenotypes: obesity-resistant BALB/c mice and the obesity-prone C57BL/6 mice. [18F]BODIPY 1 is a radioactive dye that processed both radioactivity for PET imaging and fluorescence signal for in vitro mechanism study. RESULTS Through the co-staining of cancer cells with BODIPY 1 and MitoTracker, we found BODIPY 1 mainly accumulated in cell mitochondria in vitro. Fluorescence imaging of primary brown and white adipocytes further confirmed BODIPY 1 had significantly higher accumulation in primary brown adipocytes compared with primary white adipocytes. We evaluated [18F]BODIPY 1 for BAT imaging in both obesity-resistant BALB/c mice and obesity-prone C57BL/6 mice. Indeed, [18F]BODIPY 1 was efficiently taken up by BAT in both mouse genotypes (6.40 ± 1.98 %ID/g in obesity-resistant BALB/c mice (n = 8) and 5.37 ± 0.82 %ID/g in obesity-prone C57BL/6 mice (n = 7)). Although norepinephrine stimulation could increase the absolute BAT uptake, the enhancement is not significant in both genotypes (p > 0.05) at current sample size. These results suggest BAT uptake of [18F]BODIPY 1 may be independent of BAT thermogenic activity. As a comparison, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) PET imaging was performed in obesity-resistant BALB/c mice. Significantly increased uptake was observed in adrenergically activated BAT (10.08 ± 2.52 %ID/g, n = 3) but not in inactive BAT (3.803 ± 0.70 %ID/g; n = 3). Because [18F]BODIPY 1 maintained its fluorescent property, BAT tissue was excised and studied using fluorescence microscopy. Strong fluorescence signal was observed in BAT mouse that was injected with BODIPY 1. CONCLUSIONS Unlike [18F]FDG, [18F]BODIPY 1 showed prominent accumulation in BAT under both inactive and stimulated status. [18F]BODIPY 1 may serve as a valuable BAT PET agent to possibly assess BAT mitochondria density, thus BAT thermogenic capacity after further evaluation.
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Affiliation(s)
- Hui Wang
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Mengzhe Wang
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Kantapat Chansaenpak
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yang Liu
- Center for Molecular Medicine, Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
| | - Hong Yuan
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jin Xie
- Department of Chemistry, Bio-Imaging Research Center, The University of Georgia, Athens, GA, 30602, USA
| | - Hang Yin
- Center for Molecular Medicine, Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
| | - Rosa T Branca
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Zibo Li
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Zhanhong Wu
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. .,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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6
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Santhanam P, Rowe SP, Solnes LB, Quainoo B, Ahima RS. A systematic review of imaging studies of human brown adipose tissue. Ann N Y Acad Sci 2021; 1495:5-23. [PMID: 33604891 DOI: 10.1111/nyas.14579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 01/25/2021] [Accepted: 01/31/2021] [Indexed: 02/06/2023]
Abstract
Brown adipose tissue (BAT) is involved in energy dissipation and has been linked to weight loss, insulin sensitivity, and reduced risk of atherosclerotic disease. BAT is found most often in the supraclavicular region, as well as mediastinal and paravertebral areas, and it is predominantly seen in young persons. BAT is activated by cold temperature and the sympathetic nervous system. In humans, BAT was initially detected via 2-deoxy-2-[18 F]fluoro-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT), a high-resolution molecular imaging modality used to identify and stage malignancies. Recent studies have shown that BAT can be localized using conventional imaging modalities, such as CT or magnetic resonance imaging, as well as radiotracers used for single-photon emission CT. In this systematic review, we have summarized the evidence for BAT detection in humans using various imaging techniques.
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Affiliation(s)
- Prasanna Santhanam
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Asthma and Allergy Center, Baltimore, Maryland
| | - Steven P Rowe
- Division of Nuclear Medicine, Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lilja B Solnes
- Division of Nuclear Medicine, Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Brittany Quainoo
- Columbian College of Arts and Sciences, George Washington University, Washington, DC
| | - Rexford S Ahima
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Asthma and Allergy Center, Baltimore, Maryland
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7
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Nishio M, Saeki K. The Remaining Mysteries about Brown Adipose Tissues. Cells 2020; 9:cells9112449. [PMID: 33182625 PMCID: PMC7696203 DOI: 10.3390/cells9112449] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022] Open
Abstract
Brown adipose tissue (BAT), which is a thermogenic fat tissue originally discovered in small hibernating mammals, is believed to exert anti-obesity effects in humans. Although evidence has been accumulating to show the importance of BAT in metabolism regulation, there are a number of unanswered questions. In this review, we show the remaining mysteries about BATs. The distribution of BAT can be visualized by nuclear medicine examinations; however, the precise localization of human BAT is not yet completely understood. For example, studies of 18F-fluorodeoxyglucose PET/CT scans have shown that interscapular BAT (iBAT), the largest BAT in mice, exists only in the neonatal period or in early infancy in humans. However, an old anatomical study illustrated the presence of iBAT in adult humans, suggesting that there is a discrepancy between anatomical findings and imaging data. It is also known that BAT secretes various metabolism-improving factors, which are collectively called as BATokines. With small exceptions, however, their main producers are not BAT per se, raising the possibility that there are still more BATokines to be discovered. Although BAT is conceived as a favorable tissue from the standpoint of obesity prevention, it is also involved in the development of unhealthy conditions such as cancer cachexia. In addition, a correlation between browning of mammary gland and progression of breast cancers was shown in a xenotransplantation model. Therefore, the optimal condition should be carefully determined when BAT is considered as a measure the prevention of obesity and improvement of metabolism. Solving BAT mysteries will open a new door for health promotion via advanced understanding of metabolism regulation system.
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Affiliation(s)
- Miwako Nishio
- Department of Laboratory Molecular Genetics of Hematology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan;
| | - Kumiko Saeki
- Department of Laboratory Molecular Genetics of Hematology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan;
- Department of Regenerative Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
- Correspondence: ; Tel.: +81-3-3202-7181
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8
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Michurina S, Stafeev I, Podkuychenko N, Sklyanik I, Shestakova E, Yah'yaev K, Yurasov A, Ratner E, Menshikov M, Parfyonova Y, Shestakova M. Decreased UCP-1 expression in beige adipocytes from adipose-derived stem cells of type 2 diabetes patients associates with mitochondrial ROS accumulation during obesity. Diabetes Res Clin Pract 2020; 169:108410. [PMID: 32882342 DOI: 10.1016/j.diabres.2020.108410] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/17/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Adipose derived stem cells (ADSC) are defective in metabolic disorders in various functionalities and properties including differentiation, multipotent state, metabolism and immunomodulation. However, the role of ADSC beiging potential in promoting of type 2 diabetes mellitus (T2DM) development remains unclear. Here we uncover association between potential of subcutaneous ADSC to beige differentiation and T2DM in patients with obesity. METHODS ADSC were isolated from subcutaneous adipose tissue of patients with long morbid obesity (BMI > 35 kg/m2) and normal glucose tolerance (NGT) or T2DM. ADSC were differentiated into white or beige adipocytes and levels of thermogenic markers, lipid metabolism and electron transport chain (ETC) genes was analyzed by Western blotting and RT-PCR. ROS production was estimated by fluorescent microscopy. RESULTS We have shown decreased UCP-1 expression in beige adipocytes from T2DM patients. Nevertheless, signal and expression activities of lipolysis were equal in NGT and T2DM beige adipocytes. Expression analysis of ETC genes also has not shown any statistically significant differences. Interestingly, we revealed increased mitochondrial ROS production in T2DM beige adipocytes during beige differentiation. CONCLUSIONS In summary, compromised UCP1 expression in beige adipocytes of T2DM patients may cause increase of mitochondrial ROS. Elevated oxidative level is liable to act as damaging mechanism leading to insulin resistance or, alternatively, serve as compensatory mechanism for thermogenesis activation.
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Affiliation(s)
- Svetlana Michurina
- National Medical Research Center for Cardiology, Moscow, Russia; M.V.Lomonosov Moscow State University, Moscow, Russia.
| | - Iurii Stafeev
- National Medical Research Center for Cardiology, Moscow, Russia; Endocrinology Research Centre, Moscow, Russia.
| | - Nikita Podkuychenko
- National Medical Research Center for Cardiology, Moscow, Russia; M.V.Lomonosov Moscow State University, Moscow, Russia; Endocrinology Research Centre, Moscow, Russia
| | | | | | - Kamil Yah'yaev
- Central Clinical Hospital #1 of LLC Russian Railways, Moscow, Russia
| | - Anatoliy Yurasov
- Central Clinical Hospital #1 of LLC Russian Railways, Moscow, Russia
| | - Elizaveta Ratner
- National Medical Research Center for Cardiology, Moscow, Russia; Endocrinology Research Centre, Moscow, Russia
| | | | - Yelena Parfyonova
- National Medical Research Center for Cardiology, Moscow, Russia; M.V.Lomonosov Moscow State University, Moscow, Russia
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Ruan HB. Developmental and functional heterogeneity of thermogenic adipose tissue. J Mol Cell Biol 2020; 12:775-784. [PMID: 32569352 PMCID: PMC7816678 DOI: 10.1093/jmcb/mjaa029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/11/2020] [Accepted: 06/12/2020] [Indexed: 12/18/2022] Open
Abstract
The obesity epidemic continues to rise as a global health challenge. Thermogenic brown and beige adipocytes dissipate chemical energy as heat, providing an opportunity for developing new therapeutics for obesity and related metabolic diseases. Anatomically, brown adipose tissue is distributed as discrete depots, while beige adipocytes exist within certain depots of white adipose tissue. Developmentally, brown and beige adipocytes arise from multiple embryonic progenitor populations that are distinct and overlapping. Functionally, they respond to a plethora of stimuli to engage uncoupling protein 1-dependent and independent thermogenic programs, thus improving systemic glucose homeostasis, lipid metabolism, and the clearance of branched-chain amino acids. In this review, we highlight recent advances in our understanding of the molecular and cellular mechanisms that contribute to the developmental and functional heterogeneity of thermogenic adipose tissue.
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Affiliation(s)
- Hai-Bin Ruan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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10
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Hai W, Wu X, Shi S, Yang Y, Yang Z, Li B, Xu Y, Peng J. The effects of season change and fasting on Brown adipose tissue FDG-PET in mice. Biochem Biophys Res Commun 2020; 529:398-403. [DOI: 10.1016/j.bbrc.2020.06.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 12/15/2022]
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Reinisch I, Schreiber R, Prokesch A. Regulation of thermogenic adipocytes during fasting and cold. Mol Cell Endocrinol 2020; 512:110869. [PMID: 32439414 DOI: 10.1016/j.mce.2020.110869] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
Cold exposure activates brown and brown-like adipocytes that dissipate large amounts of glucose and fatty acids via uncoupling protein 1 (UCP1) to drive non-shivering thermogenesis (NST). Evidence for the existence of these thermogenic adipocytes in adult humans gave rise to a renaissance in research on brown adipose tissue, establishing it as linchpin of energy homeostasis and metabolic health. Besides low ambient temperature, shortage or excess of food affect thermoregulation. Upon high caloric meals thermogenic adipocytes burn excess calories and maintain energy balance. In contrast, in conditions of nutrient deprivation, counter-regulatory mechanisms prevent thermogenic adipocytes from "wasting" energy substrates that need to be conserved. In this review, we discuss cell-autonomous mechanisms, metabolites, and hormones that modify NST in response to nutrient fluctuations. In particular, we focus on how thermogenic adipocytes balance thermogenesis with systemic energy homeostasis during fasting periods.
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Affiliation(s)
- Isabel Reinisch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
| | - Andreas Prokesch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria; BioTechMed-Graz, 8010, Graz, Austria.
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12
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New Role for Growth/Differentiation Factor 15 in the Survival of Transplanted Brown Adipose Tissues in Cooperation with Interleukin-6. Cells 2020; 9:cells9061365. [PMID: 32492819 PMCID: PMC7349565 DOI: 10.3390/cells9061365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/18/2020] [Accepted: 05/27/2020] [Indexed: 12/15/2022] Open
Abstract
To identify factors involved in the earliest phase of the differentiation of human embryonic stem cells (hESCs) into brown adipocytes (BAs), we performed multi-time point microarray analyses. We found that growth/differentiation factor 15 (GDF15) expressions were specifically upregulated within three days of differentiation, when expressions of immature hESC markers were sustained. Although GDF15 expressions continued to increase in the subsequent differentiation phases, GDF15-deficient hESCs differentiated into mature BAs (Day 10) without apparent abnormalities. In addition, GDF15-deficient mice had normal brown adipose tissue (BAT) and were metabolically healthy. Unexpectedly, we found that interleukin-6 (IL6) expression was significantly lowered in the BAT of GDF15-/- mice. In addition, GDF15-/- hESCs showed abortive IL6 expressions in the later phase (>Day 6) of the differentiation. Interestingly, GDF15 expression was markedly repressed throughout the whole course of the differentiation of IL6-/- hESCs into BAs, indicating IL6 is essential for the induction of GDF15 in the differentiation of hESCs. Finally, intraperitoneally transplanted BAT grafts of GDF15-/- donor mice, but not those of wild-type (WT) mice, failed in the long-term survival (12 weeks) in GDF15-/- recipient mice. Collectively, GDF15 is required for long-term survival of BAT grafts by creating a mutual gene induction loop with IL6.
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13
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Shoji A, Takahashi Y, Osato S, Sugawara M. An enzyme-modified capillary as a platform for simultaneous fluorometric detection of d-glucose and l- lactate. J Pharm Biomed Anal 2019; 163:1-8. [PMID: 30268727 DOI: 10.1016/j.jpba.2018.09.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/10/2018] [Accepted: 09/14/2018] [Indexed: 10/28/2022]
Abstract
The preparation of a glass capillary pattered with lipid layers on which lactate dehydrogenase (LDH) and glucose dehydrogenase (GDH) were regionally adsorbed and its application for simultaneous detection of d-glucose and l-lactate in human serum is described. A lipid layer was formed on the surface of BSA-unabsorbed octadecyltrichlorosilane (OTS) inner wall of a glass capillary. The electrostatic charge of the lipid layer was a key factor for adsorbing the enzymes on the lipid layer. The fluorescence intensities were observed at each enzyme site in the presence of diaphorase (DIA), β-nicotinamide-adenine dinucleotide oxidized (NAD), resazurin, d-glucose and l-lactate. The fluorescence intensities at each enzyme site increased with an increase in the concentration of d-glucose and l-lactate=with the detection limits of 32 μM and 4.9 μM, respectively.
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Affiliation(s)
- Atsushi Shoji
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo, 156-8550, Japan; School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan.
| | - Yusuke Takahashi
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo, 156-8550, Japan
| | - Saki Osato
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo, 156-8550, Japan
| | - Masao Sugawara
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo, 156-8550, Japan
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14
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Gao Y, Cao Y, Cui X, Wang X, Zhou Y, Huang F, Wang X, Wen J, Xie K, Xu P, Guo X, You L, Ji C. miR-199a-3p regulates brown adipocyte differentiation through mTOR signaling pathway. Mol Cell Endocrinol 2018; 476:155-164. [PMID: 29753771 DOI: 10.1016/j.mce.2018.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/23/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Recent discoveries of functional brown adipocytes in mammals illuminates their therapeutic potential for combating obesity and its associated diseases. However, on account of the limited amount and activity in adult humans of brown adipocyte depots, identification of miRNAs and characterization their regulatory roles in human brown adipogenesis are urgently needed. This study focused on the role of microRNA (miR)-199a-3p in human brown adipocyte differentiation and thermogenic capacity. A decreased expression pattern of miR-199a-3p was consistently observed during the differentiation course of brown adipocytes in mice and humans. Conversely, its level was induced during the differentiation course of human white pre-adipocytes derived from visceral fat. miR-199a-3p expression was relatively abundant in interscapular BAT (iBAT) and differentially regulated in the activated and aging BAT in mice. Additionally, miR-199a-3p expression level in human brown adipocytes was observed decreased upon thermogenic activation and increased by aging-related stimuli. Using primary pre-adipocytes, miR-199a-3p over-expression was capable of attenuating lipid accumulation and adipogenic gene expression as well as impairing brown adipocytes' metabolic characteristics as revealed by decreased mitochondrial DNA content and respiration. Suppression of miR-199a-3p by a locked nucleic acid (LNA) modified-anti-miR led to increased differentiation and thermogenesis in human brown adipocytes. By combining target prediction and examination, we identified mechanistic target of rapamycin kinase (mTOR) as a direct target of miR-199a-3p that affected brown adipogenesis and thermogenesis. Our results point to a novel role for miR-199a-3p and its downstream effector mTOR in human brown adipocyte differentiation and maintenance of thermogenic characteristics, which can be manipulated as therapeutic targets against obesity and its related metabolic disorders.
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Affiliation(s)
- Yao Gao
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Yan Cao
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Xianwei Cui
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Xingyun Wang
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Yahui Zhou
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Fangyan Huang
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Xing Wang
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Juan Wen
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Kaipeng Xie
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Pengfei Xu
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Xirong Guo
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China
| | - Lianghui You
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China.
| | - Chenbo Ji
- Nanjing Maternity and Child Health Care Institute, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China.
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15
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Nahon KJ, Doornink F, Straat ME, Botani K, Martinez-Tellez B, Abreu-Vieira G, van Klinken JB, Voortman GJ, Friesema ECH, Ruiz JR, van Velden FHP, de Geus-Oei LF, Smit F, Pereira Arias-Bouda LM, Berbée JFP, Jazet IM, Boon MR, Rensen PCN. Effect of sitagliptin on energy metabolism and brown adipose tissue in overweight individuals with prediabetes: a randomised placebo-controlled trial. Diabetologia 2018; 61:2386-2397. [PMID: 30145664 PMCID: PMC6182651 DOI: 10.1007/s00125-018-4716-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 07/09/2018] [Indexed: 01/12/2023]
Abstract
AIMS/HYPOTHESIS The aim of this study was to evaluate the effect of sitagliptin on glucose tolerance, plasma lipids, energy expenditure and metabolism of brown adipose tissue (BAT), white adipose tissue (WAT) and skeletal muscle in overweight individuals with prediabetes (impaired glucose tolerance and/or impaired fasting glucose). METHODS We performed a randomised, double-blinded, placebo-controlled trial in 30 overweight, Europid men (age 45.9 ± 6.2 years; BMI 28.8 ± 2.3 kg/m2) with prediabetes in the Leiden University Medical Center and the Alrijne Hospital between March 2015 and September 2016. Participants were initially randomly allocated to receive sitagliptin (100 mg/day) (n = 15) or placebo (n = 15) for 12 weeks, using a randomisation list that was set up by an unblinded pharmacist. All people involved in the study as well as participants were blinded to group assignment. Two participants withdrew from the study prior to completion (both in the sitagliptin group) and were subsequently replaced with two new participants that were allocated to the same treatment. Before and after treatment, fasting venous blood samples and skeletal muscle biopsies were obtained, OGTT was performed and body composition, resting energy expenditure and [18F] fluorodeoxyglucose ([18F]FDG) uptake by metabolic tissues were assessed. The primary study endpoint was the effect of sitagliptin on BAT volume and activity. RESULTS One participant from the sitagliptin group was excluded from analysis, due to a distribution error, leaving 29 participants for further analysis. Sitagliptin, but not placebo, lowered glucose excursion (-40%; p < 0.003) during OGTT, accompanied by an improved insulinogenic index (+38%; p < 0.003) and oral disposition index (+44%; p < 0.003). In addition, sitagliptin lowered serum concentrations of triacylglycerol (-29%) and very large (-46%), large (-35%) and medium-sized (-24%) VLDL particles (all p < 0.05). Body weight, body composition and energy expenditure did not change. In skeletal muscle, sitagliptin increased mRNA expression of PGC1β (also known as PPARGC1B) (+117%; p < 0.05), a main controller of mitochondrial oxidative energy metabolism. Although the primary endpoint of change in BAT volume and activity was not met, sitagliptin increased [18F] FDG uptake in subcutaneous WAT (sWAT; +53%; p < 0.05). Reported side effects were mild and transient and not necessarily related to the treatment. CONCLUSIONS/INTERPRETATION Twelve weeks of sitagliptin in overweight, Europid men with prediabetes improves glucose tolerance and lipid metabolism, as related to increased [18F] FDG uptake by sWAT, rather than BAT, and upregulation of the mitochondrial gene PGC1β in skeletal muscle. Studies on the effect of sitagliptin on preventing or delaying the progression of prediabetes into type 2 diabetes are warranted. TRIAL REGISTRATION ClinicalTrials.gov NCT02294084. FUNDING This study was funded by Merck Sharp & Dohme Corp, Dutch Heart Foundation, Dutch Diabetes Research Foundation, Ministry of Economic Affairs and the University of Granada.
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Affiliation(s)
- Kimberly J Nahon
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Fleur Doornink
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Maaike E Straat
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Kani Botani
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Borja Martinez-Tellez
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
- PROFITH 'Promoting Fitness and Health through Physical Activity' research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Gustavo Abreu-Vieira
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan B van Klinken
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Gardi J Voortman
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Edith C H Friesema
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Jonatan R Ruiz
- PROFITH 'Promoting Fitness and Health through Physical Activity' research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Floris H P van Velden
- Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Lioe-Fee de Geus-Oei
- Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Frits Smit
- Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Nuclear Medicine, Alrijne Hospital, Leiderdorp, the Netherlands
| | - Lenka M Pereira Arias-Bouda
- Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Nuclear Medicine, Alrijne Hospital, Leiderdorp, the Netherlands
| | - Jimmy F P Berbée
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Ingrid M Jazet
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Mariëtte R Boon
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands.
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands.
| | - Patrick C N Rensen
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, post zone C7Q, P. O. Box 9600, 2300 RC, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
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16
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Mosqueda-Solís A, Sánchez J, Portillo MP, Palou A, Picó C. Combination of Capsaicin and Hesperidin Reduces the Effectiveness of Each Compound To Decrease the Adipocyte Size and To Induce Browning Features in Adipose Tissue of Western Diet Fed Rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:9679-9689. [PMID: 30183290 DOI: 10.1021/acs.jafc.8b02611] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We explored the potential of hesperidin and capsaicin, separately and in combination, to induce white adipose tissue (WAT) browning and to help body weight management in Western diet-fed rats. Adult male Wistar rats were fed for 8 weeks with Western diet and treated daily with hesperidin (100 mg/kg/day), capsaicin (4 mg/kg/day), hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day), or the vehicle. Hesperidin and capsaicin separately, but not (or to a lesser extent) the combination, resulted in a decreased size of adipocytes and induced emergence of multilocular brown-like adipocytes positive for UCP1 and CIDEA in retroperitoneal WAT. Expression levels of browning markers, such as Prdm16, in inguinal WAT also increased with capsaicin treatment compared with the vehicle (145% ± 17% vs 92% ± 21%, P < 0.05), but no significant effects were found with the combination (106% ± 12%). Thus, the combination of both bioactives reduces the effectiveness of each compound to decrease the adipocyte size and induce WAT browning.
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Affiliation(s)
- Andrea Mosqueda-Solís
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Nutrigenomics and Obesity Group) , University of the Balearic Islands , 07122 Palma , Spain
- Nutrition and Obesity Group, Department of Nutrition and Food Science, Faculty of Pharmacy and Lucio Lascaray Research Center , University of the Basque Country (UPV/EHU) , Vitoria , Spain
| | - Juana Sánchez
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Nutrigenomics and Obesity Group) , University of the Balearic Islands , 07122 Palma , Spain
- Instituto de Investigación Sanitaria Illes Balears , 07010 Palma , Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) , Instituto de Salud Carlos III (ISCIII) , Madrid , Spain
| | - María P Portillo
- Nutrition and Obesity Group, Department of Nutrition and Food Science, Faculty of Pharmacy and Lucio Lascaray Research Center , University of the Basque Country (UPV/EHU) , Vitoria , Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) , Instituto de Salud Carlos III (ISCIII) , Madrid , Spain
| | - Andreu Palou
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Nutrigenomics and Obesity Group) , University of the Balearic Islands , 07122 Palma , Spain
- Instituto de Investigación Sanitaria Illes Balears , 07010 Palma , Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) , Instituto de Salud Carlos III (ISCIII) , Madrid , Spain
| | - Catalina Picó
- Laboratory of Molecular Biology, Nutrition and Biotechnology (Nutrigenomics and Obesity Group) , University of the Balearic Islands , 07122 Palma , Spain
- Instituto de Investigación Sanitaria Illes Balears , 07010 Palma , Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) , Instituto de Salud Carlos III (ISCIII) , Madrid , Spain
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17
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Fuse S, Nirengi S, Amagasa S, Homma T, Kime R, Endo T, Sakane N, Matsushita M, Saito M, Yoneshiro T, Kurosawa Y, Hamaoka T. Brown adipose tissue density measured by near-infrared time-resolved spectroscopy in Japanese, across a wide age range. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-9. [PMID: 29900702 DOI: 10.1117/1.jbo.23.6.065002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/21/2018] [Indexed: 06/08/2023]
Abstract
F18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) along with computed tomography (CT) is a standard method for assessing brown adipose tissue (BAT) activity. We tested the usefulness of near-infrared time-resolved spectroscopy (NIRTRS) as a simple and noninvasive method for evaluating BAT density (BAT-d) by examining the effects of some factors known to influence BAT activity. The total hemoglobin concentration as a parameter of BAT-d was evaluated using NIRTRS in the supraclavicular region in 413 Japanese individuals. The associations were analyzed between BAT-d and sex, age, the percentages of body fat (%BF), visceral fat (VF), and the seasonal ambient temperature (AmT) fluctuations. Age was associated with decreased BAT-d (P < 0.05). There was no sex difference in the BAT-d, except for those in their twenties. Multivariate analyses revealed that %BF and VF were correlated with BAT-d, and the lower AmT (around 4°C or 5°C) for 4 and 6 weeks prior to the measurement day was associated with an increase in the BAT-d. Our NIRTRS results were analogous to those reported with FDG18-PET / CT, indicating the usefulness of NIRTRS. BAT-d might increase during the 4 and 6 weeks after the AmT decreases to lower than 4°C or 5°C.
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Affiliation(s)
- Sayuri Fuse
- Tokyo Medical University, Department of Sports Medicine for Health Promotion, Shinjuku-ku, Tokyo, Japan
| | - Shinsuke Nirengi
- Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Division of Preven, Japan
| | - Shiho Amagasa
- Tokyo Medical University, Department of Preventive Medicine and Public Health, Shinjuku-ku, Tokyo, Japan
| | - Toshiyuki Homma
- Daito Bunka University, Faculty of Sports and Health Science, Higashimatsuyama-shi, Saitama, Japan
| | - Ryotaro Kime
- Tokyo Medical University, Department of Sports Medicine for Health Promotion, Shinjuku-ku, Tokyo, Japan
| | - Tasuki Endo
- Tokyo Medical University, Department of Sports Medicine for Health Promotion, Shinjuku-ku, Tokyo, Japan
| | - Naoki Sakane
- Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Division of Preven, Japan
| | - Mami Matsushita
- Tenshi College, Department of Nutrition, Higashi-ku, Sapporo, Japan
| | | | - Takeshi Yoneshiro
- University of California, UCSF Diabetes Center, Department of Cell and Tissue Biology, San Francisco, United States
| | - Yuko Kurosawa
- Tokyo Medical University, Department of Sports Medicine for Health Promotion, Shinjuku-ku, Tokyo, Japan
| | - Takafumi Hamaoka
- Tokyo Medical University, Department of Sports Medicine for Health Promotion, Shinjuku-ku, Tokyo, Japan
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18
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Chondronikola M, Beeman SC, Wahl RL. Non-invasive methods for the assessment of brown adipose tissue in humans. J Physiol 2018; 596:363-378. [PMID: 29119565 PMCID: PMC5792561 DOI: 10.1113/jp274255] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/04/2017] [Indexed: 01/10/2023] Open
Abstract
Brown adipose tissue (BAT) is a recently rediscovered tissue in people that has shown promise as a potential therapeutic target against obesity and its metabolic abnormalities. Reliable non-invasive assessment of BAT volume and activity is critical to allow its importance in metabolic control to be evaluated. Positron emission tomography/computed tomography (PET/CT) in combination with 2-deoxy-2-[18 F]fluoroglucose administration is currently the most frequently used and most established method for the detection and quantification of activated BAT in humans. However, it involves radiation exposure and can detect activated (e.g. after cold exposure), but not quiescent, BAT. Several alternative methods that overcome some of these limitations have been developed including different PET approaches, single-photon emission imaging, CT, magnetic resonance based approaches, contrast-enhanced ultrasound, near infrared spectroscopy, and temperature assessment of fat depots containing brown adipocytes. The purpose of this review is to summarize and critically evaluate the currently available methods that non-invasively probe various aspects of BAT biology in order to assess BAT volume and/or metabolism. Although several of these methods show promise for the non-invasive assessment of BAT volume and function, further research is needed to optimize them to enable an accurate, reproducible and practical means for the assessment of human BAT content and its metabolic function.
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Affiliation(s)
- Maria Chondronikola
- Center for Human NutritionWashington University School of MedicineSt LouisMOUSA
- Harokopio University of AthensAthensGreece
| | - Scott C. Beeman
- Department of Radiology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
| | - Richard L. Wahl
- Department of Radiology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
- Department of Radiation Oncology, Mallinckrodt Institute of RadiologyWashington University School of MedicineSt LouisMOUSA
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19
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20
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Dong M, Lin J, Lim W, Jin W, Lee HJ. Role of brown adipose tissue in metabolic syndrome, aging, and cancer cachexia. Front Med 2017; 12:130-138. [PMID: 29119382 DOI: 10.1007/s11684-017-0555-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 04/29/2017] [Indexed: 02/07/2023]
Abstract
Brown adipose tissue (BAT) plays a fundamental role in maintaining body temperature by producing heat. BAT that had been know to exist only in mammals and the human neonate has received great attention for the treatment of obesity and diabetes due to its important function in energy metabolism, ever since it is recently reported that human adults have functional BAT. In addition, beige adipocytes, brown adipocytes in white adipose tissue (WAT), have also been shown to take part in whole body metabolism. Multiple lines of evidence demonstrated that transplantation or activation of BAT or/and beige adipocytes reversed obesity and improved insulin sensitivity. Furthermore, many genes involved in BATactivation and/or the recruitment of beige cells have been found, thereby providing new promising strategies for future clinical application of BAT activation to treat obesity and metabolic diseases. This review focuses on recent advances of BAT function in the metabolic aspect and the relationship between BAT and cancer cachexia, a pathological process accompanied with decreased body weight and increased energy expenditure in cancer patients. The underlying possible mechanisms to reduce BAT mass and its activity in the elderly are also discussed.
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Affiliation(s)
- Meng Dong
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,The University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Jun Lin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,The University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wonchung Lim
- Department of Sports Medicine, College of Health Science, Cheongju University, Cheongju, 363-764, Republic of Korea
| | - Wanzhu Jin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hyuek Jong Lee
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,Center for Vascular Research, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea.
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21
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Abstract
Adipose tissue plays a central role in regulating whole-body energy and glucose homeostasis through its subtle functions at both organ and systemic levels. On one hand, adipose tissue stores energy in the form of lipid and controls the lipid mobilization and distribution in the body. On the other hand, adipose tissue acts as an endocrine organ and produces numerous bioactive factors such as adipokines that communicate with other organs and modulate a range of metabolic pathways. Moreover, brown and beige adipose tissue burn lipid by dissipating energy in the form of heat to maintain euthermia, and have been considered as a new way to counteract obesity. Therefore, adipose tissue dysfunction plays a prominent role in the development of obesity and its related disorders such as insulin resistance, cardiovascular disease, diabetes, depression and cancer. In this review, we will summarize the recent findings of adipose tissue in the control of metabolism, focusing on its endocrine and thermogenic function.
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Affiliation(s)
- Liping Luo
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
| | - Meilian Liu
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
- Department of Biochemistry and Molecular BiologyUniversity of New Mexico Health Sciences Center,
Albuquerque, New Mexico, USA
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22
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Gómez-Hernández A, Beneit N, Escribano Ó, Díaz-Castroverde S, García-Gómez G, Fernández S, Benito M. Severe Brown Fat Lipoatrophy Aggravates Atherosclerotic Process in Male Mice. Endocrinology 2016; 157:3517-28. [PMID: 27414981 DOI: 10.1210/en.2016-1148] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Obesity is one of the major risk factors for the development of cardiovascular diseases and is characterized by abnormal accumulation of adipose tissue, including perivascular adipose tissue (PVAT). However, brown adipose tissue (BAT) activation reduces visceral adiposity. To demonstrate that severe brown fat lipoatrophy might accelerate atherosclerotic process, we generated a new mouse model without insulin receptor (IR) in BAT and without apolipoprotein (Apo)E (BAT-specific IR knockout [BATIRKO];ApoE(-/-) mice) and assessed vascular and metabolic alterations associated to obesity. In addition, we analyzed the contribution of the adipose organ to vascular inflammation. Brown fat lipoatrophy induces visceral adiposity, mainly in gonadal depot (gonadal white adipose tissue [gWAT]), severe glucose intolerance, high postprandial glucose levels, and a severe defect in acute insulin secretion. BATIRKO;ApoE(-/-) mice showed greater hypertriglyceridemia than the obtained in ApoE(-/-) and hypercholesterolemia similar to ApoE(-/-) mice. BATIRKO;ApoE(-/-) mice, in addition to primary insulin resistance in BAT, also showed a significant decrease in insulin signaling in liver, gWAT, heart, aorta artery, and thoracic PVAT. More importantly, our results suggest that severe brown fat lipoatrophy aggravates the atherosclerotic process, characterized by a significant increase of lipid depots, atherosclerotic coverage, lesion size and complexity, increased macrophage infiltration, and proinflammatory markers expression. Finally, an increase of TNF-α and leptin as well as a decrease of adiponectin by BAT, gWAT, and thoracic PVAT might also be responsible of vascular damage. Our results suggest that severe brown lipoatrophy aggravates atherosclerotic process. Thus, BAT activation might protect against obesity and its associated metabolic alterations.
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Affiliation(s)
- Almudena Gómez-Hernández
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Nuria Beneit
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Óscar Escribano
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Sabela Díaz-Castroverde
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Gema García-Gómez
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Silvia Fernández
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
| | - Manuel Benito
- Biochemistry and Molecular Biology II Department, School of Pharmacy, Complutense University of Madrid; Health Research Institute of San Carlos Clinic Hospital; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas 28020 Madrid, Spain
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Mukherjee J, Baranwal A, Schade KN. Classification of Therapeutic and Experimental Drugs for Brown Adipose Tissue Activation: Potential Treatment Strategies for Diabetes and Obesity. Curr Diabetes Rev 2016; 12:414-428. [PMID: 27183844 PMCID: PMC5425649 DOI: 10.2174/1573399812666160517115450] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 05/06/2016] [Accepted: 05/12/2016] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Increasing efforts are being made towards pharmacologic activation of brown adipose tissue (BAT) in animals and humans for potential use in the treatment of obesity and diabetes. We and others have reported a number of animal studies using either experimental or therapeutic drugs. There are now efforts to translate these findings to human studies. The goal of this review is to evaluate the various drugs currently being used that have the potential for BAT activation. METHODS Drugs were classified into 4 classes based on their mechanism of action. Class 1 drugs include the use of β3 adrenoceptor agonists for BAT activation. Class 2 drugs include drugs that affect norepinephrine levels and activate BAT with the potential of reducing obesity. Class 3 includes activators of peroxisome proliferator-activated receptor-γ in pursuit of lowering blood sugar, weight loss and diabetes and finally Class 4 includes natural products and other emerging drugs with limited information on BAT activation and their effects on diabetes and weight loss. RESULTS Class 1 drugs are high BAT activators followed by Class 2 and 3. Some of these drugs have now been extended to diabetes and obesity animal models and human BAT studies. Drugs in Class 3 are used clinically for Type 2 diabetes, but the extent of BAT involvement is unclear. CONCLUSION Further studies on the efficacy of these drugs in diabetes and measuring their effects on BAT activation using noninvasive imaging will help in establishing a clinical role of BAT.
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Affiliation(s)
- Jogeshwar Mukherjee
- B140 Medical Sciences, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697-5000, USA.
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Brown adipose tissue: a potential target in the fight against obesity and the metabolic syndrome. Clin Sci (Lond) 2015; 129:933-49. [DOI: 10.1042/cs20150339] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BAT (brown adipose tissue) is the main site of thermogenesis in mammals. It is essential to ensure thermoregulation in newborns. It is also found in (some) adult humans. Its capacity to oxidize fatty acids and glucose without ATP production contributes to energy expenditure and glucose homoeostasis. Brown fat activation has thus emerged as an attractive therapeutic target for the treatment of obesity and the metabolic syndrome. In the present review, we integrate the recent advances on the metabolic role of BAT and its relation with other tissues as well as its potential contribution to fighting obesity and the metabolic syndrome.
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The role of active brown adipose tissue in human metabolism. Eur J Nucl Med Mol Imaging 2015; 43:355-361. [DOI: 10.1007/s00259-015-3166-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/05/2015] [Indexed: 12/19/2022]
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Blondin DP, Labbé SM, Turcotte EE, Haman F, Richard D, Carpentier AC. A critical appraisal of brown adipose tissue metabolism in humans. ACTA ACUST UNITED AC 2015. [DOI: 10.2217/clp.15.14] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Celi FS, Le TN, Ni B. Physiology and relevance of human adaptive thermogenesis response. Trends Endocrinol Metab 2015; 26:238-47. [PMID: 25869212 DOI: 10.1016/j.tem.2015.03.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 12/11/2022]
Abstract
In homoeothermic organisms, the preservation of core temperature represents a primal function, and its costs in terms of energy expenditure can be considerable. In modern humans, the endogenous thermoregulation mechanisms have been replaced by clothing and environmental control, and the maintenance of thermoneutrality has been successfully achieved by manipulation of the micro- and macroenvironment. The rediscovery of the presence and activity of brown adipose tissue in adult humans has renewed the interest on adaptive thermogenesis (AT) as a means to facilitate weight loss and improve carbohydrate metabolism. The aim of this review is to describe the recent advancements in the study of this function, and to assess the potential and limitations of exploiting AT for environmental/behavioral, and pharmacological interventions.
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Affiliation(s)
- Francesco S Celi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
| | - Trang N Le
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Bin Ni
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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Abstract
Obesity is the result of disequilibrium between energy intake and energy expenditure (EE). Successful long-term weight loss is difficult to achieve with current strategies for the correction of this caloric imbalance. Non-shivering thermogenesis (NST) in brown adipose tissue (BAT) is a possible therapeutic target for the prevention and treatment of obesity and associated metabolic diseases. In recent years, more knowledge about the function and stimulation of bat has been obtained. The sympathetic nervous system (SNS) is currently seen as the main effector for brown fat function. Also, interplay between the thyroid axis and SNS plays an important role in BAT thermogenesis. Almost daily new pathways for the induction of BAT thermogenesis and 'browning' of white adipose tissue (WAT) are identified. Especially the activation of BAT via endogenous pathways has received strong scientific attention. Here we will discuss the relevance of several pathways in activating BAT and their implications for the treatment of obesity. In this review we will focus on the discussion of the most promising endocrine and paracrine pathways to stimulate BAT, by factors and pathways that naturally occur in the human body.
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Affiliation(s)
- Evie Broeders
- Department of Human Biology, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre , Maastricht , the Netherlands
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Abstract
Brown adipose tissue (BAT) is the site of sympathetically activated adaptive thermogenesis during cold exposure and after hyperphagia, thereby controlling whole-body energy expenditure (EE) and body fat. BAT thermogenesis is primarily dependent on the energy-dissipating activity of uncoupling protein 1 (UCP1). There are two types of UCP1-expressing adipocyte, classical brown and beige/brite adipocytes. Recent radionuclide studies have demonstrated the existence of metabolically active BAT composed of mainly beige/brite adipocytes in adult humans. Human BAT is activated by acute cold exposure, being positively correlated to cold-induced increases in EE. The inverse relationship between the BAT activity and body fatness suggests that BAT, because of its energy-dissipating activity, is protective against body fat accumulation. In fact, either repeated cold exposure or daily ingestion of some food ingredients acting on transient receptor potential channels recruited BAT in association with increased EE and decreased body fat. Moreover, possible contribution of BAT to glucose tolerance has been suggested. In addition to the sympathetic nervous system, some endocrine factors also have potential for activation/recruitment of BAT. Thus, BAT is a promising therapeutic target for combating human obesity and related metabolic disorders.
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Affiliation(s)
- Takeshi Yoneshiro
- Department of Anatomy, Hokkaido University Graduate School of Medicine , Sapporo , Japan
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Sidossis L, Kajimura S. Brown and beige fat in humans: thermogenic adipocytes that control energy and glucose homeostasis. J Clin Invest 2015; 125:478-86. [PMID: 25642708 DOI: 10.1172/jci78362] [Citation(s) in RCA: 483] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Brown adipose tissue (BAT), a specialized fat that dissipates energy to produce heat, plays an important role in the regulation of energy balance. Two types of thermogenic adipocytes with distinct developmental and anatomical features exist in rodents and humans: classical brown adipocytes and beige (also referred to as brite) adipocytes. While classical brown adipocytes are located mainly in dedicated BAT depots of rodents and infants, beige adipocytes sporadically reside with white adipocytes and emerge in response to certain environmental cues, such as chronic cold exposure, a process often referred to as "browning" of white adipose tissue. Recent studies indicate the existence of beige adipocytes in adult humans, making this cell type an attractive therapeutic target for obesity and obesity-related diseases, including type 2 diabetes. This Review aims to cover recent progress in our understanding of the anatomical, developmental, and functional characteristics of brown and beige adipocytes and discuss emerging questions, with a special emphasis on adult human BAT.
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Porter C, Chondronikola M, Sidossis LS. The Therapeutic Potential of Brown Adipocytes in Humans. Front Endocrinol (Lausanne) 2015; 6:156. [PMID: 26528238 PMCID: PMC4602197 DOI: 10.3389/fendo.2015.00156] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/18/2015] [Indexed: 12/20/2022] Open
Abstract
Obesity and its metabolic consequences represent a significant clinical problem. From a thermodynamic standpoint, obesity results from a discord in energy intake and expenditure. To date, lifestyle interventions based on reducing energy intake and/or increasing energy expenditure have proved ineffective in the prevention and/or treatment of obesity, owing to poor long-term adherence to such interventions. Thus, an effective strategy to prevent or correct obesity is currently lacking. As the combustion engines of our cells, mitochondria play a critical role in energy expenditure. At a whole-body level, approximately 80% of mitochondrial membrane potential generated by fuel oxidation is used to produce ATP, and the remaining 20% is lost through heat-producing uncoupling reactions. The coupling of mitochondrial respiration to ATP production represents an important component in whole-body energy expenditure. Brown adipose tissue (BAT) is densely populated with mitochondria containing the inner mitochondrial proton carrier uncoupling protein 1 (UCP1). UCP1 uncouples oxidative phosphorylation, meaning that mitochondrial membrane potential is dissipated as heat. The recent rediscovery of BAT depots in adult humans has rekindled scientific interest in the manipulation of mitochondrial uncoupling reactions as a means to increase metabolic rate, thereby counteracting obesity and its associated metabolic phenotype. In this article, we discuss the evidence for the role BAT plays in metabolic rate and glucose and lipid metabolism in humans and the potential for UCP1 recruitment in the white adipose tissue of humans. While the future holds much promise for a therapeutic role of UCP1 expressing adipocytes in human energy metabolism, particularly in the context of obesity, tissue-specific strategies that activate or recruit UCP1 in human adipocytes represent an obligatory translational step for this early promise to be realized.
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Affiliation(s)
- Craig Porter
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
- *Correspondence: Craig Porter and Labros S. Sidossis, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA, ;
| | - Maria Chondronikola
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, USA
| | - Labros S. Sidossis
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
- Department of Nutrition and Dietetics, Harokopio University of Athens, Athens, Greece
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
- *Correspondence: Craig Porter and Labros S. Sidossis, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA, ;
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Wu C, Cheng W, Sun Y, Dang Y, Gong F, Zhu H, Li N, Li F, Zhu Z. Activating brown adipose tissue for weight loss and lowering of blood glucose levels: a microPET study using obese and diabetic model mice. PLoS One 2014; 9:e113742. [PMID: 25462854 PMCID: PMC4252055 DOI: 10.1371/journal.pone.0113742] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/29/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose This study aims at using 18F-FDG microPET to monitor the brown adipose tissue (BAT) glucose metabolism in obese and diabetic mouse models under different interventions, and study the therapeutic potential of BAT activation for weight loss and lowering of blood glucose in these models. Methods Obese mice were established by a high-fat diet for eight weeks, and diabetes mellitus(DM) models were induced with Streptozocin in obese mice. 18F-FDG microPET was used to monitor BAT function during obese and DM modeling, and also after BRL37344 (a β3-adrenergic receptor agonist) or levothyroxine treatment. The BAT function was correlated with the body weight and blood glucose levels. Results Compared with the controls, the obese mice and DM mice showed successively lower 18F-FDG uptake in the interscapular BAT (P = 0.036 and <0.001, respectively). After two-week BRL37344 treatment, the BAT uptake was significantly elevated in both obese mice (P = 0.010) and DM mice (P = 0.004), accompanied with significantly decreased blood glucose levels (P = 0.023 and 0.036, respectively). The BAT uptake was negatively correlated with the blood glucose levels in both obese mice (r = −0.71, P = 0.003) and DM mice (r = −0.74, P = 0.010). BRL37344 treatment also caused significant weight loss in the obese mice (P = 0.001). Levothyroxine treatment increased the BAT uptake in the control mice (P = 0.025) and obese mice (P = 0.013), but not in the DM mice (P = 0.45). Conclusion The inhibited BAT function in obese and DM mice can be re-activated by β3-adrenergic receptor agonist or thyroid hormone, and effective BAT activation may lead to weight loss and blood glucose lowering. Activating BAT can provide a new treatment strategy for obesity and DM.
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Affiliation(s)
- Chenxi Wu
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Wuying Cheng
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yi Sun
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yonghong Dang
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Fengying Gong
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Huijuan Zhu
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Naishi Li
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Fang Li
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Zhaohui Zhu
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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Responses of the insulin signaling pathways in the brown adipose tissue of rats following cold exposure. PLoS One 2014; 9:e99772. [PMID: 24915042 PMCID: PMC4051765 DOI: 10.1371/journal.pone.0099772] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 05/19/2014] [Indexed: 01/28/2023] Open
Abstract
The insulin signaling pathway is critical for the control of blood glucose levels. Brown adipose tissue (BAT) has also been implicated as important in glucose homeostasis. The effect of short-term cold exposure on this pathway in BAT has not been explored. We evaluated the effect of 4 hours of cold exposure on the insulin pathway in the BAT of rats. Whole genomic microarray chips were used to examine the transcripts of the pathway in BAT of rats exposed to 4°C and 22°C for 4 hours. The 4 most significantly altered pathways following 4 hours of cold exposure were the insulin signaling pathway, protein kinase A, PI3K/AKT and ERK/MAPK signaling. The insulin signaling pathway was the most affected. In the documented 142 genes of the insulin pathway, 42 transcripts (29.6%) responded significantly to this cold exposure with the least false discovery rate (Benjamini-Hochberg Multiple Testing: −log10 (p-value) = 7.18). Twenty-seven genes (64%) were up-regulated, including the insulin receptor (Insr), insulin substrates 1 and 2 (Irs1 and Irs2). Fifteen transcripts (36%) were down-regulated. Multiple transcripts of the primary target and secondary effector targets for the insulin signaling were also up-regulated, including those for carbohydrate metabolism. Using western blotting, we demonstrated that the cold induced higher Irs2, Irs1, and Akt-p protein levels in the BAT than in the BAT of controls maintained at room temperature, and higher Akt-p protein level in the muscle. Conclusion: this study demonstrated that 4 hours of cold exposure stimulated the insulin signaling pathway in the BAT and muscle of overnight fasted rats. This raises the possibility that acute cold stimulation may have potential to improve glucose clearance and insulin sensitivity.
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Bauwens M, Wierts R, van Royen B, Bucerius J, Backes W, Mottaghy F, Brans B. Molecular imaging of brown adipose tissue in health and disease. Eur J Nucl Med Mol Imaging 2014; 41:776-91. [PMID: 24509875 DOI: 10.1007/s00259-013-2611-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/07/2013] [Indexed: 12/25/2022]
Abstract
PURPOSE Brown adipose tissue (BAT) has transformed from an interfering tissue in oncological (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to an independent imaging research field. This review takes the perspective from the imaging methodology on which human BAT research has come to rely on heavily. METHODS This review analyses relevant PubMed-indexed publications that discuss molecular imaging methods of BAT. In addition, reported links between BAT and human diseases such as obesity are discussed, and the possibilities for imaging in these fields are highlighted. Radiopharmaceuticals aiming at several different biological mechanisms of BAT are discussed and evaluated. RESULTS Prospective, dedicated studies allow visualization of BAT function in a high percentage of human subjects. BAT dysfunction has been implicated in obesity, linked with diabetes and associated with cachexia and atherosclerosis. Presently, (18)F-FDG PET/CT is the most useful tool for evaluating therapies aiming at BAT activity. In addition to (18)F-FDG, other radiopharmaceuticals such as (99m)Tc-sestamibi, (123)I-metaiodobenzylguanidine (MIBG), (18)F-fluorodopa and (18)F-14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid (FTHA) may have a potential for visualizing other aspects of BAT activity. MRI methods are under continuous development and provide the prospect of functional imaging without ionizing radiation. CONCLUSION Molecular imaging of BAT can be used to quantitatively assess different aspects of BAT metabolic activity.
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Affiliation(s)
- Matthias Bauwens
- Department of Medical Imaging, Division of Nuclear Medicine, MUMC, Maastricht, Netherlands
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Abstract
Brown adipose tissue (BAT) has emerged as a therapeutic target for the treatment of obesity. Activation of BAT in human beings could also have beneficial metabolic effects that might resolve common complications of obesity, such as type 2 diabetes, by ameliorating the glucolipotoxic pathological changes that underlie the development of peripheral insulin resistance and impaired insulin secretion due to pancreatic β-cell failure. Evidence from rodent models suggests that BAT activation improves glucose homoeostasis through several mechanisms, which could point to new strategies to optimise stimulation of BAT in human beings and reverse insulin resistance in peripheral tissues.
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Affiliation(s)
- Vivian Peirce
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
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McArdle MA, Finucane OM, Connaughton RM, McMorrow AM, Roche HM. Mechanisms of obesity-induced inflammation and insulin resistance: insights into the emerging role of nutritional strategies. Front Endocrinol (Lausanne) 2013; 4:52. [PMID: 23675368 PMCID: PMC3650620 DOI: 10.3389/fendo.2013.00052] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 04/22/2013] [Indexed: 12/11/2022] Open
Abstract
Obesity and associated chronic inflammation initiate a state of insulin resistance (IR). The secretion of chemoattractants such as MCP-1 and MIF and of cytokines IL-6, TNF-α, and IL-1β, draw immune cells including dendritic cells, T cells, and macrophages into adipose tissue (AT). Dysfunctional AT lipid metabolism leads to increased circulating free fatty acids, initiating inflammatory signaling cascades in the population of infiltrating cells. A feedback loop of pro-inflammatory cytokines exacerbates this pathological state, driving further immune cell infiltration and cytokine secretion and disrupts the insulin signaling cascade. Disruption of normal AT function is causative of defects in hepatic and skeletal muscle glucose homeostasis, resulting in systemic IR and ultimately the development of type 2 diabetes. Pharmaceutical strategies that target the inflammatory milieu may have some potential; however there are a number of safety concerns surrounding such pharmaceutical approaches. Nutritional anti-inflammatory interventions could offer a more suitable long-term alternative; whilst they may be less potent than some pharmaceutical anti-inflammatory agents, this may be advantageous for long-term therapy. This review will investigate obese AT biology, initiation of the inflammatory, and insulin resistant environment; and the mechanisms through which dietary anti-inflammatory components/functional nutrients may be beneficial.
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Affiliation(s)
- Maeve A. McArdle
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Orla M. Finucane
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Ruth M. Connaughton
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Aoibheann M. McMorrow
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Helen M. Roche
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
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Mirbolooki MR, Constantinescu CC, Pan ML, Mukherjee J. Targeting presynaptic norepinephrine transporter in brown adipose tissue: a novel imaging approach and potential treatment for diabetes and obesity. Synapse 2012; 67:79-93. [PMID: 23080264 DOI: 10.1002/syn.21617] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/12/2012] [Indexed: 12/12/2022]
Abstract
Brown adipose tissue (BAT) plays a significant role in metabolism. In this study, we report the use of atomoxetine (a clinically applicable norepinephrine reuptake inhibitor) for (18)F-FDG PET imaging of BAT and its effects on heat production and blood glucose concentration. Fasted-male Sprague-Dawley rats were administered with intravenous (18)F-FDG. The same rats were treated with atomoxetine (0.1 mg/kg, i.v.) 30 min before (18)F-FDG administration. To confirm the β-adrenergic effects, propranolol (β-adrenergic inhibitor) 5 mg/kg was given intraperitoneally 30 min prior to atomoxetine administration. The effect of atomoxetine on BAT metabolism was assessed in fasted and non-fasted rats and on BAT temperature and blood glucose in fasted rats. In (18)F-FDG PET/CT images, interscapular BAT (IBAT) and other areas of BAT were clearly visualized. When rats were fasted, atomoxetine (0.1 mg/kg) increased the (18)F-FDG uptake of IBAT by factor of 24 within 30 min. Propranolol reduced the average (18)F-FDG uptake of IBAT significantly. Autoradiography of IBAT and white adipose tissue confirmed the data obtained by PET. When rats were not fasted, atomoxetine-induced increase of (18)F-FDG uptake in IBAT was delayed and occurred in 120 min. For comparison, direct stimulation of β(3)-adrenreceptors in non-fasted rats with CL-316, 243 occurred within 30 min. Atomoxetine-induced IBAT activation was associated with higher IBAT temperature and lower blood glucose. This was mediated by inhibition of norepinephrine reuptake transporters in IBAT leading to increased norepinephrine concentration in the synapse. Increased synaptic norepinephrine activates β(3)-adrenreceptors resulting in BAT hypermetabolism that is visible and quantifiable by (18)F-FDG PET/CT.
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Affiliation(s)
- M Reza Mirbolooki
- Preclinical Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, California 92697-5000, USA.
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Nishio M, Yoneshiro T, Nakahara M, Suzuki S, Saeki K, Hasegawa M, Kawai Y, Akutsu H, Umezawa A, Yasuda K, Tobe K, Yuo A, Kubota K, Saito M, Saeki K. Production of functional classical brown adipocytes from human pluripotent stem cells using specific hemopoietin cocktail without gene transfer. Cell Metab 2012; 16:394-406. [PMID: 22958922 DOI: 10.1016/j.cmet.2012.08.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 06/30/2012] [Accepted: 08/01/2012] [Indexed: 02/06/2023]
Abstract
Brown adipose tissue is attracting much attention due to its antiobestic effects; however, its development and involvement in metabolic improvement remain elusive. Here we established a method for a high-efficiency (>90%) differentiation of human pluripotent stem cells (hPSCs) into functional classical brown adipocytes (BAs) using specific hemopoietin cocktail (HC) without exogenous gene transfer. BAs were not generated without HC, and lack of a component of HC induced white adipocyte (WA) marker expressions. hPSC-derived BA (hPSCdBA) showed respiratory and thermogenic activation by β-adrenergic receptor (AdrRβ) stimuli and augmented lipid and glucose tolerance, whereas human multipotent stromal cell-derived WA (hMSCdWA) improved lipid but inhibited glucose metabolism. Cotransplantation of hPSCdBA normalized hMSCdWA-induced glucose intolerance. Surprisingly, hPSCdBAs expressed various hemopoietin genes, serving as stroma for myeloid progenitors. Moreover, AdrRβ stimuli enhanced recovery from chemotherapy-induced myelosuppression. Our study enhances our understanding of BA, identifying roles in metabolic and hemogenic regulation.
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Affiliation(s)
- Miwako Nishio
- Department of Disease Control, Research Institute, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
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The Depiction of Brown Adipose Tissue Is Related to Disease Status in Pediatric Patients With Lymphoma. AJR Am J Roentgenol 2012; 198:909-13. [DOI: 10.2214/ajr.11.7488] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Mirbolooki MR, Constantinescu CC, Pan ML, Mukherjee J. Quantitative assessment of brown adipose tissue metabolic activity and volume using 18F-FDG PET/CT and β3-adrenergic receptor activation. EJNMMI Res 2011; 1:30. [PMID: 22214183 PMCID: PMC3250993 DOI: 10.1186/2191-219x-1-30] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 12/01/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Brown adipose tissue [BAT] metabolism in vivo is vital for the development of novel strategies in combating obesity and diabetes. Currently, BAT is activated at low temperatures and measured using 2-deoxy-2-18F-fluoro-D-glucose [18F-FDG] positron-emission tomography [PET]. We report the use of β3-adrenergic receptor-mediated activation of BAT at ambient temperatures using (R, R)-5-[2-[2,3-(3-chlorphenyl)-2-hydroxyethyl-amino]propyl]-1,3-benzodioxole-2,2-dicarboxylate, disodium salt [CL316,243] (a selective β3-adrenoceptor agonist) and measured by 18F-FDG PET/computed tomography [CT]. METHODS Control and CL316,243-treated (2 mg/kg) male Sprague-Dawley rats were administered with 18F-FDG for PET/CT studies and were compared to animals at cold temperatures. Receptor-blocking experiments were carried out using propranolol (5 mg/kg). Dose effects of CL316,243 were studied by injecting 0.1 to 1 mg/kg 30 min prior to 18F-FDG administration. Imaging results were confirmed by autoradiography, and histology was done to confirm BAT activation. RESULTS CL316,243-activated interscapular BAT [IBAT], cervical, periaortic, and intercostal BATs were clearly visualized by PET. 18F-FDG uptake of IBAT was increased 12-fold by CL316,243 vs. 1.1-fold by cold exposure when compared to controls. 18F-FDG uptake of the CL-activated IBAT was reduced by 96.0% using intraperitoneal administration of propranolol. Average 18F-FDG uptake of IBAT increased 3.6-, 3.5-, and 7.6-fold by doses of 0.1, 0.5, and 1 mg/kg CL, respectively. Ex vivo 18F-FDG autoradiography and histology of transverse sections of IBAT confirmed intense uptake in the CL-activated group and activated IBAT visualized by PET. CONCLUSION Our study indicated that BAT metabolic activity could be evaluated by 18F-FDG PET using CL316,243 at ambient temperature in the rodent model. This provides a feasible and reliable method to study BAT metabolism.
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Affiliation(s)
- M Reza Mirbolooki
- Preclinical Imaging Center, Department of Psychiatry and Human Behavior, University of California-Irvine, Irvine, CA, 92697, USA.
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Yilmaz Y, Ones T, Purnak T, Ozguven S, Kurt R, Atug O, Turoglu HT, Imeryuz N. Association between the presence of brown adipose tissue and non-alcoholic fatty liver disease in adult humans. Aliment Pharmacol Ther 2011; 34:318-23. [PMID: 21631560 DOI: 10.1111/j.1365-2036.2011.04723.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND The presence of active brown adipose tissue (BAT) has been associated with a reduced risk of obesity in adult humans. AIM To examine whether the presence and activity of BAT in patients undergoing PET-CT examinations is related to the presence of fatty liver. METHOD We retrospectively analysed 3666 consecutive PET-CT whole-body scans performed on a total of 1832 patients who were referred for suspected malignancies. BAT-positive subjects (BAT+) were defined as subjects who showed substantial amounts of brown adipose tissue on PET-CT scans. In areas where uptake of [(18)F]FDG was identified by CT for BAT, the maximal standardised uptake values (SUVmax), defined as the maximum activity per millilitre within the region of interest divided by the injected dose in megabecquerels per gram of body weight, were determined. A ratio of mean liver attenuation to spleen attenuation <0.8 on CT scans was considered to indicate NAFLD. RESULTS Thirty patients of the 1832 screened individuals (2%) demonstrated brown fat uptake (BAT+ subjects). Ninety matched individuals without evidence of BAT on PET scans (BAT- subjects) were enrolled for comparison purposes. After adjustment for potential confounders, the odds ratio for having NAFLD was significantly higher for BAT- subjects (3.12, 95% confidence interval = 1.03-9.88, P < 0.05). The SUVmax for brown fat tissue was significantly correlated with the ratio of mean liver attenuation to spleen attenuation (P < 0.05). CONCLUSION The presence of brown adipose tissue in adulthood is independently associated with a lower likelihood of NAFLD diagnosed by CT findings.
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Affiliation(s)
- Y Yilmaz
- Department of Gastroenterology, Marmara University, School of Medicine, Pendik, Istanbul, Turkey.
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Betz MJ, Enerbäck S. Therapeutic prospects of metabolically active brown adipose tissue in humans. Front Endocrinol (Lausanne) 2011; 2:86. [PMID: 22649390 PMCID: PMC3355987 DOI: 10.3389/fendo.2011.00086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/12/2011] [Indexed: 12/23/2022] Open
Abstract
The world-wide obesity epidemic constitutes a severe threat to human health and wellbeing and poses a major challenge to health-care systems. Current therapeutic approaches, relying mainly on reduced energy intake and/or increased exercise energy expenditure, are generally of limited effectiveness. Previously believed to be present only in children, the existence of metabolically active brown adipose tissue (BAT) was recently demonstrated also in healthy human adults. The physiological role of BAT is to dissipate chemical energy, mainly from fatty acids, as heat to maintain body temperature in cold environments. Recent studies indicate that the activity of BAT is negatively correlated with overweight and obesity, findings that raise the exciting possibility of new and effective weight reduction therapies based on increased BAT energy expenditure, a process likely to be amenable to pharmacological intervention.
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Affiliation(s)
- Matthias J. Betz
- Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of GöteborgGöteborg, Sweden
- Medizinische Klinik, Campus Innenstadt, Klinikum der Ludwig-Maximilians-Universität MünchenMunich, Germany
| | - Sven Enerbäck
- Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of GöteborgGöteborg, Sweden
- *Correspondence: Sven Enerbäck, Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Göteborg, Medicinaregatan 9A, Box 440, Göteborg 40530, Sweden. e-mail:
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