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Xiang K, Pan J, Yu J, Xiao L, Sun SK, Cheng R. A hemicyanine-based near-infrared fluorescent probe with large Stokes shift for non-invasive bioimaging of brown adipose tissue. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:5272-5279. [PMID: 39016035 DOI: 10.1039/d4ay00658e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Brown adipose tissue (BAT), characterized by the presence of numerous mitochondria, plays a key role in metabolism and energy expenditure. Accurately reporting the presence and activation of BAT is beneficial to study obesity, diabetes, and other metabolic disorders. Near-infrared (NIR) fluorescence imaging has the advantages of high sensitivity, non-radioactivity, and simple operation. However, most NIR probes for BAT imaging exhibit small Stokes shifts, which may lead to self-quenching, reducing the signal-to-noise ratio, and introducing cross-talk. Herein, we rationally designed and synthesized a series of hemicyanine-based NIR fluorescent probes HCYBAT-1-3. Among them, HCYBAT-1 demonstrated favorable properties such as near-infrared emission (776 nm), large Stokes shift (139 nm), good biocompatibility and specific mitochondrial targeting (Pearson's colocalization coefficient of 0.87). Meanwhile, HCYBAT-1 was successfully employed to differentiate BAT from white adipose tissue (WAT). Quantitative analysis of NIR fluorescent images showed that HCYBAT-1 could be used for real-time monitoring of BAT activation in mice stimulated by norepinephrine (NE) and cold exposure. Overall, probe HCYBAT-1 showcased its efficacy in non-invasive evaluation of BAT metabolism in vivo with high selectivity and sensitivity.
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Affiliation(s)
- Ke Xiang
- School of Medical Imaging, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Jinbin Pan
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Jiaojiao Yu
- School of Medical Imaging, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Lehui Xiao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
| | - Shao-Kai Sun
- School of Medical Imaging, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Ran Cheng
- School of Medical Imaging, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin 300203, China.
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de Paula Faria D, da Silva Vera CC, Marques FLN, Sapienza MT. Repeatability of brown adipose tissue activation measured by [ 18F]FDG PET after beta3-adrenergic stimuli in a mouse model. Nucl Med Biol 2023; 126-127:108390. [PMID: 37804561 DOI: 10.1016/j.nucmedbio.2023.108390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/18/2023] [Accepted: 09/28/2023] [Indexed: 10/09/2023]
Abstract
This study aimed to evaluate the repeatability of brown adipose tissue (BAT) activation measured by [18F]FDG-PET after beta3-adrenergic stimuli with CL316243 in mice. METHODS Male C57BL/6 mice underwent [18F]FDG-PET at baseline without stimulation (T0-NS), on three consecutive days after intravenous administration of the selective β3-adrenergic agonist CL316243 (T1-CL, T2-CL, T3-CL), and without stimuli after 1 and 2 weeks (T7-NS and T14-NS). The standardized uptake value (SUVmax), BAT metabolic volume (BMV), and total BAT glycolysis (TBG) were measured in each scanning session, with statistical groupwise comparisons by ANOVA and post hoc Tukey test. RESULTS SUVmax, BMV, and TBG values showed no significant differences between the three PET scans without stimuli, but were significantly higher after CL316243 administration (p < 0.0001). The mean coefficient of variation (CoV) of PET within individuals was 49 % at baseline but only 9 % with pharmacological stimulation. CONCLUSIONS The study demonstrated that administration of the selective β3-adrenergic receptor agonist CL316243 (CL) in mice leads to consistent metabolic activation of brown adipose tissue (BAT), as measured by [18F]FDG-PET. We also demonstrated metabolic activation by repeated pharmacological challenge, without evidence of hysteresis. Thus, the methods used in the current work should serve for further studies on BAT metabolism in experimental animals, with translational value for clinical research.
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Affiliation(s)
- Daniele de Paula Faria
- Laboratory of Nuclear Medicine (LIM 43), Department of Radiology and Oncology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Cleinando Clemente da Silva Vera
- Laboratory of Nuclear Medicine (LIM 43), Department of Radiology and Oncology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Fabio Luiz Navarro Marques
- Laboratory of Nuclear Medicine (LIM 43), Department of Radiology and Oncology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Marcelo Tatit Sapienza
- Laboratory of Nuclear Medicine (LIM 43), Department of Radiology and Oncology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil.
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Maliszewska K, Miniewska K, Godlewski A, Gosk W, Mojsak M, Kretowski A, Ciborowski M. Changes in plasma endocannabinoids concentrations correlate with 18F-FDG PET/MR uptake in brown adipocytes in humans. Front Mol Biosci 2023; 10:1073683. [PMID: 37564131 PMCID: PMC10411954 DOI: 10.3389/fmolb.2023.1073683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 07/13/2023] [Indexed: 08/12/2023] Open
Abstract
Introduction: Recent data suggest a possible role of endocannabinoids in the regulation of brown adipose tissue (BAT) activity. Those findings indicate potential treatment options for obesity. The aim of this study was to evaluate the relationship between plasma endocannabinoids concentrations and the presence of BAT in humans. Methods: The study group consisted of 25 subjects divided into two groups: BAT positive BAT(+), (n = 17, median age = 25 years) and BAT negative BAT(-), (n = 8, median age = 28 years). BAT was estimated using 18F-FDG PET/MR after 2 h of cold exposure. The level of plasma endocannabinoids was assessed at baseline, 60 min and 120 min of cold exposure. Results: In both groups, BAT(+) and BAT(-), during the cooling, we observed a decrease of the same endocannabinoids: arachidonoylethanolamide (AEA), eicosapentaenoyl ethanolamide (EPEA) and oleoyl ethanolamide (OEA) with a much more profound decline in BAT(+) subjects. Statistically significant fall of PEA (palmitoylethanolamide) and SEA (stearoylethanolamide) concentrations after 60 min (FC = 0.7, p = 0.007 and FC = 0.8, p = 0.03, respectively) and 120 min (FC = 0.81, p = 0.004, and FC = 0.9, p = 0.01, respectively) of cooling was observed only in individuals with BAT. Conclusion: We noticed the profound decline of endocannabinoids concentrations in subjects with increased 18F-FDG PET/MR uptake in BAT. Identification of a new molecules related to BAT activity may create a new target for obesity treatment.
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Affiliation(s)
- Katarzyna Maliszewska
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland
| | - Katarzyna Miniewska
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Adrian Godlewski
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Wioleta Gosk
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Malgorzata Mojsak
- Independent Laboratory of Molecular Imaging, Medical University of Bialystok, Bialystok, Poland
| | - Adam Kretowski
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland
| | - Michal Ciborowski
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
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Pekkarinen L, Kantonen T, Oikonen V, Haaparanta-Solin M, Aarnio R, Dickens AM, von Eyken A, Latva-Rasku A, Dadson P, Kirjavainen AK, Rajander J, Kalliokoski K, Rönnemaa T, Nummenmaa L, Nuutila P. Lower abdominal adipose tissue cannabinoid type 1 receptor availability in young men with overweight. Obesity (Silver Spring) 2023; 31:1844-1858. [PMID: 37368516 DOI: 10.1002/oby.23770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/16/2023] [Accepted: 03/06/2023] [Indexed: 06/29/2023]
Abstract
OBJECTIVE Cannabinoid type 1 receptors (CB1R) modulate feeding behavior and energy homeostasis, and the CB1R tone is dysgulated in obesity. This study aimed to investigate CB1R availability in peripheral tissue and brain in young men with overweight versus lean men. METHODS Healthy males with high (HR, n = 16) or low (LR, n = 20) obesity risk were studied with fluoride 18-labeled FMPEP-d2 positron emission tomography to quantify CB1R availability in abdominal adipose tissue, brown adipose tissue, muscle, and brain. Obesity risk was assessed by BMI, physical exercise habits, and familial obesity risk, including parental overweight, obesity, and type 2 diabetes. To assess insulin sensitivity, fluoro-[18 F]-deoxy-2-D-glucose positron emission tomography during hyperinsulinemic-euglycemic clamp was performed. Serum endocannabinoids were analyzed. RESULTS CB1R availability in abdominal adipose tissue was lower in the HR than in the LR group, whereas no difference was found in other tissues. CB1R availability of abdominal adipose tissue and brain correlated positively with insulin sensitivity and negatively with unfavorable lipid profile, BMI, body adiposity, and inflammatory markers. Serum arachidonoyl glycerol concentration was associated with lower CB1R availability of the whole brain, unfavorable lipid profile, and higher serum inflammatory markers. CONCLUSIONS The results suggest endocannabinoid dysregulation already in the preobesity state.
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Affiliation(s)
- Laura Pekkarinen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Tatu Kantonen
- Turku PET Centre, University of Turku, Turku, Finland
- Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Vesa Oikonen
- Turku PET Centre, University of Turku, Turku, Finland
| | - Merja Haaparanta-Solin
- Turku PET Centre, University of Turku, Turku, Finland
- MediCity Research Laboratory, University of Turku, Turku, Finland
| | | | - Alex M Dickens
- Turku Bioscience Centre, University of Turku, Turku, Finland
- Åbo Akademi University, Turku, Finland
| | - Annie von Eyken
- Turku Bioscience Centre, University of Turku, Turku, Finland
- Åbo Akademi University, Turku, Finland
| | | | - Prince Dadson
- Turku PET Centre, University of Turku, Turku, Finland
| | | | - Johan Rajander
- Turku PET Centre, Åbo Akademi University, Turku, Finland
| | | | - Tapani Rönnemaa
- Department of Endocrinology, Turku University Hospital, Turku, Finland
- Department of Medicine, University of Turku, Turku, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Psychology, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
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Zhu B, Liang SH, Ran C. Imaging Brown Adipose Tissue with TSPO PET Tracers in Preclinical Animal Studies. Methods Mol Biol 2023; 2662:147-156. [PMID: 37076678 DOI: 10.1007/978-1-0716-3167-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
Brown adipose tissue (BAT) is closely associated with thermogenesis and related to numerous diseases, including type 2 diabetes, nonalcoholic fatty liver disease (NAFLD), and obesity. Using molecular imaging technologies to monitor BAT could facilitate etiology elucidation, disease diagnosis, and therapeutics development. Translocator protein (TSPO), an 18 kDa protein that mainly locates on the outer mitochondrial membrane, has been proven as a promising biomarker for monitoring BAT mass. Here, we lay out the steps for imaging BAT with TSPO PET tracer [18F]-DPA in mouse studies.
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Affiliation(s)
- Biyue Zhu
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Chongzhao Ran
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
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Cheng R, Fujinaga M, Yang J, Rong J, Haider A, Ogasawara D, Van RS, Shao T, Chen Z, Zhang X, Calderon Leon ER, Zhang Y, Mori W, Kumata K, Yamasaki T, Xie L, Sun S, Wang L, Ran C, Shao Y, Cravatt B, Josephson L, Zhang MR, Liang SH. A novel monoacylglycerol lipase-targeted 18F-labeled probe for positron emission tomography imaging of brown adipose tissue in the energy network. Acta Pharmacol Sin 2022; 43:3002-3010. [PMID: 35513432 PMCID: PMC9622914 DOI: 10.1038/s41401-022-00912-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/13/2022] [Indexed: 11/09/2022] Open
Abstract
Monoacylglycerol lipase (MAGL) constitutes a serine hydrolase that orchestrates endocannabinoid homeostasis and exerts its function by catalyzing the degradation of 2-arachidonoylglycerol (2-AG) to arachidonic acid (AA). As such, selective inhibition of MAGL represents a potential therapeutic and diagnostic approach to various pathologies including neurodegenerative disorders, metabolic diseases and cancers. Based on a unique 4-piperidinyl azetidine diamide scaffold, we developed a reversible and peripheral-specific radiofluorinated MAGL PET ligand [18F]FEPAD. Pharmacokinetics and binding studies on [18F]FEPAD revealed its outstanding specificity and selectivity towards MAGL in brown adipose tissue (BAT) - a tissue that is known to be metabolically active. We employed [18F]FEPAD in PET studies to assess the abundancy of MAGL in BAT deposits of mice and found a remarkable degree of specific tracer binding in the BAT, which was confirmed by post-mortem tissue analysis. Given the negative regulation of endocannabinoids on the metabolic BAT activity, our study supports the concept that dysregulation of MAGL is likely linked to metabolic disorders. Further, we now provide a suitable imaging tool that allows non-invasive assessment of MAGL in BAT deposits, thereby paving the way for detailed mechanistic studies on the role of BAT in endocannabinoid system (ECS)-related pathologies.
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Affiliation(s)
- Ran Cheng
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
- School of Medical Imaging, Tianjin Medical University, Tianjin, 300203, China
| | - Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Jing Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02125, USA
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Richard S Van
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
| | - Tuo Shao
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Zhen Chen
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Xiaofei Zhang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Erick R Calderon Leon
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
| | - Yiding Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Wakana Mori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Katsushi Kumata
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Lin Xie
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Shaofa Sun
- Hubei Collaborative Innovation Centre for Non-power Nuclear Technology, College of Nuclear Technology & Chemistry and Biology, Hubei University of Science and Technology, Xianning, Hubei Province, 437100, China
| | - Lu Wang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02125, USA
| | - Yihan Shao
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
| | - Benjamin Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan.
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA.
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Zhu Y, Qi Z, Ding S. Exercise-Induced Adipose Tissue Thermogenesis and Browning: How to Explain the Conflicting Findings? Int J Mol Sci 2022; 23:13142. [PMID: 36361929 PMCID: PMC9657384 DOI: 10.3390/ijms232113142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 07/25/2023] Open
Abstract
Brown adipose tissue (BAT) has been widely studied in targeting against metabolic diseases such as obesity, type 2 diabetes and insulin resistance due to its role in nutrient metabolism and energy regulation. Whether exercise promotes adipose tissue thermogenesis and browning remains controversial. The results from human and rodent studies contradict each other. In our opinion, fat thermogenesis or browning promoted by exercise should not be a biomarker of health benefits, but an adaptation under the stress between body temperature regulation and energy supply and expenditure of multiple organs. In this review, we discuss some factors that may contribute to conflicting experimental results, such as different thermoneutral zones, gender, training experience and the heterogeneity of fat depots. In addition, we explain that a redox state in cells potentially causes thermogenesis heterogeneity and different oxidation states of UCP1, which has led to the discrepancies noted in previous studies. We describe a network by which exercise orchestrates the browning and thermogenesis of adipose tissue with total energy expenditure through multiple organs (muscle, brain, liver and adipose tissue) and multiple pathways (nerve, endocrine and metabolic products), providing a possible interpretation for the conflicting findings.
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Affiliation(s)
- Yupeng Zhu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai 200241, China
- School of Physical Education and Health, East China Normal University, Shanghai 200241, China
- Sino-French Joint Research Center of Sport Science, East China Normal University, Shanghai 200241, China
| | - Zhengtang Qi
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai 200241, China
- School of Physical Education and Health, East China Normal University, Shanghai 200241, China
| | - Shuzhe Ding
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai 200241, China
- Sino-French Joint Research Center of Sport Science, East China Normal University, Shanghai 200241, China
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8
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Abstract
The endocannabinoid system is found in most, if not all, mammalian organs and is involved in a variety of physiological functions, ranging from the control of synaptic plasticity in the brain to the modulation of smooth muscle motility in the gastrointestinal tract. This signaling complex consists of G protein-coupled cannabinoid receptors, endogenous ligands for those receptors (endocannabinoids) and enzymes/transporters responsible for the formation and deactivation of these ligands. There are two subtypes of cannabinoid receptors, CB1 and CB2, and two major endocannabinoids, arachidonoylethanolamide (anandamide) and 2-arachidonoyl-sn-glycerol (2-AG), which are produced upon demand through cleavage of distinct phospholipid precursors. All molecular components of the endocannabinoid system are represented in the adipose organ, where endocannabinoid signals are thought to regulate critical homeostatic processes, including adipogenesis, lipogenesis and thermogenesis. Importantly, obesity was found to be associated with excess endocannabinoid activity in visceral fat depots, and the therapeutic potential of normalizing such activity by blocking CB1 receptors has been the focus of substantial preclinical and clinical research. Results have been mixed thus far, mostly owing to the emergence of psychiatric side effects rooted in the protective functions served by brain endocannabinoids in mood and affect regulation. Further studies about the roles played by the endocannabinoid system in the adipose organ will offer new insights into the pathogenesis of obesity and might help identify new ways to leverage this signaling complex for therapeutic benefit.
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Affiliation(s)
- Kwang-Mook Jung
- Department of Anatomy and Neurobiology, University of California, Irvine, 3101 Gillespie NRF, Irvine, CA, 92697-1275, USA
| | - Lin Lin
- Department of Anatomy and Neurobiology, University of California, Irvine, 3101 Gillespie NRF, Irvine, CA, 92697-1275, USA
| | - Daniele Piomelli
- Department of Anatomy and Neurobiology, University of California, Irvine, 3101 Gillespie NRF, Irvine, CA, 92697-1275, USA.
- Department of Pharmacology, University of California, Irvine, Irvine, CA, 92697, USA.
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, 92697, USA.
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Yang J, Zhang H, Parhat K, Xu H, Li M, Wang X, Ran C. Molecular Imaging of Brown Adipose Tissue Mass. Int J Mol Sci 2021; 22:ijms22179436. [PMID: 34502347 PMCID: PMC8431742 DOI: 10.3390/ijms22179436] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 12/28/2022] Open
Abstract
Brown adipose tissue (BAT), a uniquely thermogenic tissue that plays an important role in metabolism and energy expenditure, has recently become a revived target in the fight against metabolic diseases, such as obesity, diabetes, and non-alcoholic fatty liver disease (NAFLD). Different from white adipose tissue (WAT), the brown adipocytes have distinctive features including multilocular lipid droplets, a large number of mitochondria, and a high expression of uncoupling protein-1 (UCP-1), as well as abundant capillarity. These histologic characteristics provide an opportunity to differentiate BAT from WAT using imaging modalities, such as PET/CT, SPECT/CT, MRI, NIRF and Ultrasound. However, most of the reported imaging methods were BAT activation dependent, and the imaging signals could be affected by many factors, including environmental temperatures and the states of the sympathetic nervous system. Accurate BAT mass detection methods that are independent of temperature and hormone levels have the capacity to track the development and changes of BAT throughout the lifetime of mammals, and such methods could be very useful for the investigation of potential BAT-related therapies. In this review, we focus on molecular imaging modalities that can detect and quantify BAT mass. In addition, their detection mechanism and limitations will be discussed as well.
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Affiliation(s)
- Jing Yang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, MA 02129, USA
- Correspondence: (J.Y.); (C.R.)
| | - Haili Zhang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Kadirya Parhat
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Hui Xu
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Mingshuang Li
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Xiangyu Wang
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China; (H.Z.); (K.P.); (H.X.); (M.L.); (X.W.)
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, MA 02129, USA
- Correspondence: (J.Y.); (C.R.)
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10
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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] [MESH Headings] [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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What Role Does the Endocannabinoid System Play in the Pathogenesis of Obesity? Nutrients 2021; 13:nu13020373. [PMID: 33530406 PMCID: PMC7911032 DOI: 10.3390/nu13020373] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
The endocannabinoid system (ECS) is an endogenous signaling system formed by specific receptors (cannabinoid type 1 and type 2 (CB1 and CB2)), their endogenous ligands (endocannabinoids), and enzymes involved in their synthesis and degradation. The ECS, centrally and peripherally, is involved in various physiological processes, including regulation of energy balance, promotion of metabolic process, food intake, weight gain, promotion of fat accumulation in adipocytes, and regulation of body homeostasis; thus, its overactivity may be related to obesity. In this review, we try to explain the role of the ECS and the impact of genetic factors on endocannabinoid system modulation in the pathogenesis of obesity, which is a global and civilizational problem affecting the entire world population regardless of age. We also emphasize that the search for potential new targets for health assessment, treatment, and the development of possible therapies in obesity is of great importance.
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12
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Hou L, Rong J, Haider A, Ogasawara D, Varlow C, Schafroth MA, Mu L, Gan J, Xu H, Fowler CJ, Zhang MR, Vasdev N, Ametamey S, Cravatt BF, Wang L, Liang SH. Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development. J Med Chem 2020; 64:123-149. [PMID: 33379862 DOI: 10.1021/acs.jmedchem.0c01459] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.
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Affiliation(s)
- Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Cassis Varlow
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Michael A Schafroth
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States.,Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Simon Ametamey
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China.,Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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Ron A, Deán-Ben XL, Reber J, Ntziachristos V, Razansky D. Characterization of Brown Adipose Tissue in a Diabetic Mouse Model with Spiral Volumetric Optoacoustic Tomography. Mol Imaging Biol 2020; 21:620-625. [PMID: 30387020 DOI: 10.1007/s11307-018-1291-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE Diabetes is associated with a deterioration of the microvasculature in brown adipose tissue (BAT) and with a decrease in its metabolic activity. Multispectral optoacoustic tomography has been recently proposed as a new tool capable of differentiating healthy and diabetic BAT by observing hemoglobin gradients and microvasculature density in cross-sectional (2D) views. We report on the use of spiral volumetric optoacoustic tomography (SVOT) for an improved characterization of BAT. PROCEDURES A streptozotocin-induced diabetes model and control mice were scanned with SVOT. Volumetric oxygen saturation (sO2) as well as total blood volume (TBV) in the subcutaneous interscapular BAT (iBAT) was quantified. Segmentation further enabled separating feeding and draining vessels from the BAT anatomical structure. RESULTS Scanning revealed a 46 % decrease in TBV and a 25 % decrease in sO2 in the diabetic iBAT with respect to the healthy control. CONCLUSIONS These results suggest that SVOT may serve as an effective tool for studying the effects of diabetes on BAT. The volumetric optoacoustic imaging probe used for the SVOT scans can be operated in a handheld mode, thus potentially providing a clinical translation route for BAT-related studies with this imaging technology.
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Affiliation(s)
- Avihai Ron
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Munich, Germany
| | - Xosé Luís Deán-Ben
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Munich, Germany
| | - Josephine Reber
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Munich, Germany
| | - Vasilis Ntziachristos
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Munich, Germany
| | - Daniel Razansky
- Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich, Munich, Germany.
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14
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Gu J, Wang X, Yang H, Li H, Wang J. Preclinical in vivo imaging for brown adipose tissue. Life Sci 2020; 249:117500. [PMID: 32147430 DOI: 10.1016/j.lfs.2020.117500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/23/2020] [Accepted: 03/02/2020] [Indexed: 12/22/2022]
Abstract
Brown adipose tissue (BAT) has multiple functions in the human body, including the production of heat and increasing energy consumption. However, BAT is also related to many kinds of diseases, such as obesity and metabolic disorders. The progression of such diseases occurs at the cellular level, and thus, imaging techniques could prove greatly beneficial for determining optimal therapeutic regimens. Currently, positron-emission tomography (PET) is considered to be the gold standard for assessing the function of activated BAT. However, PET also has inherent disadvantages, and, thus, recent efforts have been focused on exploring, and potentially developing, new imaging techniques to better observe BAT and evaluate its metabolic function. Researchers have already achieved promising success with computed tomography, magnetic resonance approaches, ultrasound, new tracers for use in PET, and other imaging techniques through in vivo and in vitro animal experiments. Since, these studies have shown that BAT may serve as an effective therapeutic target for treatment of metabolic dysfunction diseases, the development of an efficient in vivo BAT imaging technique that is applicable to humans will prove to be of great clinical value. In this review, classical PET imaging technique is highlighted as well as the current status of preclinical imaging methods developed for BAT examination.
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Affiliation(s)
- Jiaojiao Gu
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - Xinlu Wang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China.
| | - Hua Yang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - He Li
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - Jie Wang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
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15
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Frankl J, Sherwood A, Clegg DJ, Scherer PE, Öz OK. Imaging Metabolically Active Fat: A Literature Review and Mechanistic Insights. Int J Mol Sci 2019; 20:ijms20215509. [PMID: 31694216 PMCID: PMC6862590 DOI: 10.3390/ijms20215509] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/01/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023] Open
Abstract
Currently, obesity is one of the leading causes death in the world. Shortly before 2000, researchers began describing metabolically active adipose tissue on cancer-surveillance 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in adult humans. This tissue generates heat through mitochondrial uncoupling and functions similar to classical brown and beige adipose tissue in mice. Despite extensive research, human brown/beige fat's role in resistance to obesity in humans has not yet been fully delineated. FDG uptake is the de facto gold standard imaging technique when studying brown adipose tissue, although it has not been rigorously compared to other techniques. We, therefore, present a concise review of established and emerging methods to image brown adipose tissue activity in humans. Reviewed modalities include anatomic imaging with CT and magnetic resonance imaging (MRI); molecular imaging with FDG, fatty acids, and acetate; and emerging techniques. FDG-PET/CT is the most commonly used modality because of its widespread use in cancer imaging, but there are mechanistic reasons to believe other radiotracers may be more sensitive and accurate at detecting brown adipose tissue activity. Radiation-free modalities may help the longitudinal study of brown adipose tissue activity in the future.
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Affiliation(s)
- Joseph Frankl
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
| | - Amber Sherwood
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
| | - Deborah J. Clegg
- College of Nursing and Health Professions, Drexel University, 10th Floor, Room 1092, 1601 Cherry Street, Mail Stop 10501, Philadelphia, PA 19102, USA;
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA;
| | - Orhan K. Öz
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA; (J.F.); (A.S.)
- Correspondence:
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16
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Hartimath SV, Khanapur S, Boominathan R, Jiang L, Cheng P, Yong FF, Tan PW, Robins EG, Goggi JL. Imaging adipose tissue browning using the TSPO-18kDa tracer [ 18F]FEPPA. Mol Metab 2019; 25:154-158. [PMID: 31105057 PMCID: PMC6601022 DOI: 10.1016/j.molmet.2019.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/26/2019] [Accepted: 05/02/2019] [Indexed: 12/26/2022] Open
Abstract
Objectives The browning of white adipose tissue (WAT) into beige has been proposed as a strategy to enhance energy expenditure to combat the growing epidemic of obesity. Research into browning strategies are hampered by the lack of sensitive, translatable, imaging tools capable of detecting beige fat mass non-invasively. [18F]FDG is able to detect activated beige fat but provides little information on unstimulated beige fat mass. We have assessed the use of [18F]FEPPA, a tracer for the TSPO-18KDa found on the outer mitochondrial membrane, as an alternative imaging agent capable of detecting unstimulated brown fat (BAT) and beige fat. Methods Female Balb/c mice (n = 5) were treated for 7 days with the β3 adrenergic agonist CL-316,243 to induce the browning of inguinal WAT (beige fat). Animals were imaged longitudinally with [18F]FDG and [18F]FEPPA and uptake in interscapular BAT and inguinal WAT assessed. The browning of inguinal WAT was confirmed using H&E and immunohistochemical detection of UCP-1 and TSPO. Results Repeated dosing with β3-adrenergic agonist CL-316,243 caused a significant increase in [18F]FDG uptake in both interscapular BAT and inguinal WAT associated with the increased metabolic activity of brown and beige adipocytes respectively. [18F]FEPPA uptake was likewise increased in inguinal WAT but showed no increase in BAT uptake due to stimulation over the same time course. Furthermore, inguinal WAT uptake was unaffected by pharmacological blockade, indicating that [18F]FEPPA uptake is associated with the expression of mitochondria in BAT and beige adipocytes and independent of activation. Conclusion These data show that [18F]FEPPA can detect BAT and newly formed beige fat under non-stimulated, thermoneutral conditions and that uptake after stimulation is linked to mitochondrial expression as opposed to activation. TSPO-18kDa tracers can detect BAT under non-stimulated, thermoneutral conditions. TSPO-18kDa tracers can detect the formation of beige adipocytes in white adipose tissue. TSPO-18kDa tracers may aid in the development of new approaches to treat obesity.
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Affiliation(s)
- S V Hartimath
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - S Khanapur
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - R Boominathan
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - L Jiang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - P Cheng
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - F F Yong
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - P W Tan
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore
| | - E G Robins
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore; Clinical Imaging Research Centre, Yong Loo Lin School of Medicine, National University of Singapore, 117599, Singapore
| | - J L Goggi
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A* STAR), 11 Biopolis Way, #07-10, Helios, 138667, Singapore.
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Abstract
PURPOSE Brown adipose tissue (BAT) in adult humans has been recently rediscovered and intensively investigated as a new potential therapeutic target for obesity and type 2 diabetes (T2D). However, reliable assessment of BAT mass in vivo represents a considerable challenge. The purpose of this investigation is to demonstrate for the first time that human BAT depots can be imaged with a translocator protein (TSPO)-specific positron emission tomography (PET) tracer [11C]PBR28 under thermoneutral conditions. PROCEDURES In this retrospective analysis, we analyzed the images of three healthy volunteers who underwent PET/magnetic resonance (MR) imaging after injection of 14 m Ci of [11C]PBR28 at room temperature. Thirty-minute static PET images were reconstructed from the data obtained 60-90 min after the injection of the tracer. RESULTS [11C]PBR28 uptake in the neck/supraclavicular regions was identified, which was parallel to the known distribution pattern of human BAT depots. These areas co-localized with the areas of hyperintensity and corresponded to fat on T1-weighted MR images. Standardized uptake value (SUV) was used to quantify [11C]PBR28 signal in BAT depots. The average (± SD) SUV(mean) and SUVmax for BAT depots was 2.13 (± 0.33) and 3.19 (± 0.34), respectively, while the average SUV(mean) for muscle and subcutaneous adipose tissue was 0.79 (± 0.1) and 0.18 (± 0.04), respectively. CONCLUSIONS In this brief article, we provide the first evidence suggesting that [11C]PBR28, a widely available TSPO-specific PET tracer, can be used for imaging human BAT mass under thermoneutral conditions.
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18
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Carpentier AC, Blondin DP, Virtanen KA, Richard D, Haman F, Turcotte ÉE. Brown Adipose Tissue Energy Metabolism in Humans. Front Endocrinol (Lausanne) 2018; 9:447. [PMID: 30131768 PMCID: PMC6090055 DOI: 10.3389/fendo.2018.00447] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/20/2018] [Indexed: 12/16/2022] Open
Abstract
The demonstration of metabolically active brown adipose tissue (BAT) in humans primarily using positron emission tomography coupled to computed tomography (PET/CT) with the glucose tracer 18-fluorodeoxyglucose (18FDG) has renewed the interest of the scientific and medical community in the possible role of BAT as a target for the prevention and treatment of obesity and type 2 diabetes (T2D). Here, we offer a comprehensive review of BAT energy metabolism in humans. Considerable advances in methods to measure BAT energy metabolism, including nonesterified fatty acids (NEFA), chylomicron-triglycerides (TG), oxygen, Krebs cycle rate, and intracellular TG have led to very good quantification of energy substrate metabolism per volume of active BAT in vivo. These studies have also shown that intracellular TG are likely the primary energy source of BAT upon activation by cold. Current estimates of BAT's contribution to energy expenditure range at the lower end of what would be potentially clinically relevant if chronically sustained. Yet, 18FDG PET/CT remains the gold-standard defining method to quantify total BAT volume of activity, used to calculate BAT's total energy expenditure. Unfortunately, BAT glucose metabolism better reflects BAT's insulin sensitivity and blood flow. It is now clear that most glucose taken up by BAT does not fuel mitochondrial oxidative metabolism and that BAT glucose uptake can therefore be disconnected from thermogenesis. Furthermore, BAT thermogenesis is efficiently recruited upon repeated cold exposure, doubling to tripling its total oxidative capacity, with reciprocal reduction of muscle thermogenesis. Recent data suggest that total BAT volume may be much larger than the typically observed 50-150 ml with 18FDG PET/CT. Therefore, the current estimates of total BAT thermogenesis, largely relying on total BAT volume using 18FDG PET/CT, may underestimate the true contribution of BAT to total energy expenditure. Quantification of the contribution of BAT to energy expenditure begs for the development of more integrated whole body in vivo methods.
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Affiliation(s)
- André C. Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - Kirsi A. Virtanen
- Turku PET Centre, Turku University Hospital, Turku, Finland
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland (UEF), Kuopio, Finland
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
| | - François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Éric E. Turcotte
- Department of Nuclear Medicine and Radiobiology, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
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19
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Hebeisen P, Weiss U, Alker A, Kuhn B, Müller K, Wang F, Surya Prakash GK. Molecular Structure and Crystal Packing of Monofluoromethoxyarenes. European J Org Chem 2018. [DOI: 10.1002/ejoc.201701758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Paul Hebeisen
- Pharmaceutical Research & Early Development; Roche Innovation Center Basel; F. Hoffmann-La Roche AG; Grenzacherstrasse 124 4070 Basel Switzerland
| | - Urs Weiss
- Pharmaceutical Research & Early Development; Roche Innovation Center Basel; F. Hoffmann-La Roche AG; Grenzacherstrasse 124 4070 Basel Switzerland
| | - André Alker
- Pharmaceutical Research & Early Development; Roche Innovation Center Basel; F. Hoffmann-La Roche AG; Grenzacherstrasse 124 4070 Basel Switzerland
| | - Bernd Kuhn
- Pharmaceutical Research & Early Development; Roche Innovation Center Basel; F. Hoffmann-La Roche AG; Grenzacherstrasse 124 4070 Basel Switzerland
| | - Klaus Müller
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Fang Wang
- Loker Hydrocarbon Research Institute; Department of Chemistry; University of Southern California; 1661 Los Angeles CA 90089- USA
| | - G. K. Surya Prakash
- Loker Hydrocarbon Research Institute; Department of Chemistry; University of Southern California; 1661 Los Angeles CA 90089- USA
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20
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Lahesmaa M, Eriksson O, Gnad T, Oikonen V, Bucci M, Hirvonen J, Koskensalo K, Teuho J, Niemi T, Taittonen M, Lahdenpohja S, U Din M, Haaparanta-Solin M, Pfeifer A, Virtanen KA, Nuutila P. Cannabinoid Type 1 Receptors Are Upregulated During Acute Activation of Brown Adipose Tissue. Diabetes 2018; 67:1226-1236. [PMID: 29650773 DOI: 10.2337/db17-1366] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/02/2018] [Indexed: 11/13/2022]
Abstract
Activating brown adipose tissue (BAT) could provide a potential approach for the treatment of obesity and metabolic disease in humans. Obesity is associated with upregulation of the endocannabinoid system, and blocking the cannabinoid type 1 receptor (CB1R) has been shown to cause weight loss and to decrease cardiometabolic risk factors. These effects may be mediated partly via increased BAT metabolism, since there is evidence that CB1R antagonism activates BAT in rodents. To investigate the significance of CB1R in BAT function, we quantified the density of CB1R in human and rodent BAT using the positron emission tomography radioligand [18F]FMPEP-d2 and measured BAT activation in parallel with the glucose analog [18F]fluorodeoxyglucose. Activation by cold exposure markedly increased CB1R density and glucose uptake in the BAT of lean men. Similarly, β3-receptor agonism increased CB1R density in the BAT of rats. In contrast, overweight men with reduced BAT activity exhibited decreased CB1R in BAT, reflecting impaired endocannabinoid regulation. Image-guided biopsies confirmed CB1R mRNA expression in human BAT. Furthermore, CB1R blockade increased glucose uptake and lipolysis of brown adipocytes. Our results highlight that CB1Rs are significant for human BAT activity, and the CB1Rs provide a novel therapeutic target for BAT activation in humans.
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Affiliation(s)
- Minna Lahesmaa
- Turku PET Centre, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Olof Eriksson
- Turku PET Centre, Åbo Akademi, Turku, Finland
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Thorsten Gnad
- Institute of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
| | - Vesa Oikonen
- Turku PET Centre, University of Turku, Turku, Finland
| | - Marco Bucci
- Turku PET Centre, University of Turku, Turku, Finland
| | - Jussi Hirvonen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Radiology, University of Turku, Turku, Finland
| | - Kalle Koskensalo
- Turku PET Centre, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Jarmo Teuho
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Tarja Niemi
- Department of Plastic and General Surgery, Turku University Hospital, Turku, Finland
| | - Markku Taittonen
- Department of Anesthesiology, Turku University Hospital, Turku, Finland
| | | | - Mueez U Din
- Turku PET Centre, University of Turku, Turku, Finland
| | - Merja Haaparanta-Solin
- Turku PET Centre, University of Turku, Turku, Finland
- MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
| | - Kirsi A Virtanen
- Turku PET Centre, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
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21
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Takkinen JS, López-Picón FR, Kirjavainen AK, Pihlaja R, Snellman A, Ishizu T, Löyttyniemi E, Solin O, Rinne JO, Haaparanta-Solin M. [ 18F]FMPEP-d 2 PET imaging shows age- and genotype-dependent impairments in the availability of cannabinoid receptor 1 in a mouse model of Alzheimer's disease. Neurobiol Aging 2018; 69:199-208. [PMID: 29909177 DOI: 10.1016/j.neurobiolaging.2018.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 11/16/2022]
Abstract
Contradictory findings on the role of the type 1 cannabinoid receptor (CB1R) during the pathogenesis of Alzheimer's disease (AD) have been reported. Here, we evaluated the CB1R brain profile in an AD mouse model using longitudinal positron emission tomography with an inverse agonist for CB1R, [18F]FMPEP-d2. APP/PS1-21 and wild-type (n = 8 in each group) mice were repeatedly imaged between 6 to 15 months of age, accompanied by brain autoradiography, western blot, and CB1R immunohistochemistry with additional mice. [18F]FMPEP-d2 positron emission tomography demonstrated lower (p < 0.05) binding ratios in the parietotemporal cortex and hippocampus of APP/PS1-21 mice compared with age-matched wild-type mice. Western blot demonstrated no differences between APP/PS1-21 and wild-type mice in the CB1R abundance, whereas significantly lower (p < 0.05) receptor expression was observed in male than female mice. The results provide the first demonstration that [18F]FMPEP-d2 is a promising imaging tool for AD research in terms of CB1R availability, but not expression. This finding may further facilitate the development of novel therapeutic approaches based on endocannabinoid regulation.
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Affiliation(s)
- Jatta S Takkinen
- MediCity Research Laboratory, University of Turku, Turku, Finland; PET Preclinical Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Doctoral Programme in Clinical Research, University of Turku, Turku, Finland.
| | - Francisco R López-Picón
- MediCity Research Laboratory, University of Turku, Turku, Finland; PET Preclinical Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Anna K Kirjavainen
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Rea Pihlaja
- MediCity Research Laboratory, University of Turku, Turku, Finland; PET Preclinical Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Anniina Snellman
- MediCity Research Laboratory, University of Turku, Turku, Finland; PET Preclinical Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Tamiko Ishizu
- MediCity Research Laboratory, University of Turku, Turku, Finland; Institute of Biomedicine, University of Turku, Turku, Finland
| | | | - Olof Solin
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland
| | - Juha O Rinne
- Turku PET Centre, Turku University Hospital, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Merja Haaparanta-Solin
- MediCity Research Laboratory, University of Turku, Turku, Finland; PET Preclinical Laboratory, Turku PET Centre, University of Turku, Turku, Finland
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22
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van Eenige R, van der Stelt M, Rensen PCN, Kooijman S. Regulation of Adipose Tissue Metabolism by the Endocannabinoid System. Trends Endocrinol Metab 2018; 29:326-337. [PMID: 29588112 DOI: 10.1016/j.tem.2018.03.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 02/28/2018] [Accepted: 03/01/2018] [Indexed: 12/17/2022]
Abstract
White adipose tissue (WAT) stores excess energy as triglycerides, and brown adipose tissue (BAT) is specialized in dissipating energy as heat. The endocannabinoid system (ECS) is involved in a broad range of physiological processes and is increasingly recognized as a key player in adipose tissue metabolism. High ECS tonus in the fed state is associated with a disadvantageous metabolic phenotype, and this has led to a search for pharmacological strategies to inhibit the ECS. In this review we present recent developments that cast light on the regulation of adipose tissue metabolism by the ECS, and we discuss novel treatment options including the modulation of endocannabinoid synthesis and breakdown enzymes.
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Affiliation(s)
- Robin van Eenige
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mario van der Stelt
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Patrick C N Rensen
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
| | - Sander Kooijman
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
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23
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Radiosynthesis and evaluation of new PET ligands for peripheral cannabinoid receptor type 1 imaging. Bioorg Med Chem Lett 2017; 27:4114-4117. [PMID: 28757061 DOI: 10.1016/j.bmcl.2017.07.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/11/2017] [Accepted: 07/13/2017] [Indexed: 02/04/2023]
Abstract
Cannabinoid receptor type 1 (CB1) is mainly expressed in the brain, as well as being expressed in functional relevant concentrations in various peripheral tissues. 1-(4-Chlorophenyl)-3-(3-(6-(pyrrolidin-1-yl)pyridin-2-yl)phenyl)urea (PSNCBAM-1, 1) was developed as a potent allosteric antagonist for CB1 and its oral administration led to reductions in the appetite and body weight of rats. Several analogs of 1 (compounds 2 and 3) were recently identified through a series of structure-activity relationship studies. Herein, we report the synthesis of radiolabeled analogs of these compounds using [11C]COCl2 and an evaluation of their potential as PET ligands for CB1 imaging using in vitro and in vivo techniques. [11C]2 and [11C]3 were successfully synthesized in two steps using [11C]COCl2. The radiochemical yields of [11C]2 and [11C]3 were 17±8% and 20±9% (decay-corrected to the end of bombardment, based on [11C]CO2). The specific activities of [11C]2 and [11C]3 were 42±36 and 37±13GBq/μmol, respectively. The results of an in vitro binding assay using brown adipose tissue (BAT) homogenate showed that the binding affinity of 2 for CB1 (KD=15.3µM) was much higher than that of 3 (KD=26.0µM). PET studies with [11C]2 showed a high uptake of radioactivity in BAT, which decreased in animals pretreated with AM281 (a selective antagonist for CB1). In conclusion, [11C]2 may be a useful PET ligand for imaging peripheral CB1 in BAT.
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24
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Schilperoort M, Hoeke G, Kooijman S, Rensen PCN. Relevance of lipid metabolism for brown fat visualization and quantification. Curr Opin Lipidol 2016; 27:242-8. [PMID: 27023630 DOI: 10.1097/mol.0000000000000296] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Brown adipose tissue (BAT) is an emerging target to combat cardiometabolic disorders as it can take up substantial amounts of glucose and lipids from the circulation for heat production. This review focuses on new concepts in BAT physiology and discusses the need for new techniques to determine BAT activity in humans. RECENT FINDINGS Mouse studies showed that BAT activation selectively increases oxidation of lipids over glucose, by recruiting fatty acids from intracellular triglycerides. To replenish these intracellular lipid stores, brown adipocytes take up both glucose and triglyceride-derived fatty acids, resulting in attenuation of dyslipidaemia, insulin resistance and atherosclerosis. Clinical studies identified the involvement of the β3-adrenergic receptor in BAT activation and demonstrated that human BAT activation also selectively increases lipid oxidation. Notably, insulin resistance during ageing or weight gain reduces the capacity of BAT to internalize glucose, without reducing fatty acid uptake or oxidative metabolism. SUMMARY Preclinical studies established BAT as an important target to combat cardiometabolic disorders and elucidated underlying mechanisms whereas clinical studies identified therapeutic handles. Development of novel lipid-based PET-CT tracers and identification of translational biomarkers of BAT activity are required as alternatives to [F]fluorodeoxyglucose PET-CT to accelerate clinical development of BAT-activating therapeutic strategies.
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Affiliation(s)
- Maaike Schilperoort
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
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