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Colon-Mesa I, Sainz N, Corrales P, Collantes M, Kaldis P, Martinez JA, Medina-Gómez G, Moreno-Aliaga MJ, Escoté X. p27Kip1 Deficiency Impairs Brown Adipose Tissue Function Favouring Fat Accumulation in Mice. Int J Mol Sci 2023; 24:ijms24032664. [PMID: 36768986 PMCID: PMC9916555 DOI: 10.3390/ijms24032664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/13/2023] [Accepted: 01/22/2023] [Indexed: 02/01/2023] Open
Abstract
The aim of this work was to investigate the effect of the whole-body deletion of p27 on the activity of brown adipose tissue and the susceptibility to develop obesity and glucose homeostasis disturbances in mice, especially when subjected to a high fat diet. p27 knockout (p27-/-) and wild type (WT) mice were fed a normal chow diet or a high fat diet (HFD) for 10-weeks. Body weight and composition were assessed. Insulin and glucose tolerance tests and indirect calorimetry assays were performed. Histological analysis of interscapular BAT (iBAT) was carried out, and expression of key genes/proteins involved in BAT function were characterized by qPCR and Western blot. iBAT activity was estimated by 18F-fluorodeoxyglucose (18FDG) uptake with microPET. p27-/- mice were more prone to develop obesity and insulin resistance, exhibiting increased size of all fat depots. p27-/- mice displayed a higher respiratory exchange ratio. iBAT presented larger adipocytes in p27-/- HFD mice, accompanied by downregulation of both Glut1 and uncoupling protein 1 (UCP1) in parallel with defective insulin signalling. Moreover, p27-/- HFD mice exhibited impaired response to cold exposure, characterized by a reduced iBAT 18FDG uptake and difficulty to maintain body temperature when exposed to cold compared to WT HFD mice, suggesting reduced thermogenic capacity. These data suggest that p27 could play a role in BAT activation and in the susceptibility to develop obesity and insulin resistance.
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Affiliation(s)
- Ignacio Colon-Mesa
- Department of Nutrition, Food Science and Physiology and Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Irunlarrea 1, 31008 Pamplona, Spain
| | - Neira Sainz
- Department of Nutrition, Food Science and Physiology and Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Irunlarrea 1, 31008 Pamplona, Spain
| | - Patricia Corrales
- Department of Basic Sciences of Health, Area of Biochemistry and Molecular Biology, Universidad Rey Juan Carlos, Alcorcon, 28933 Madrid, Spain
| | - María Collantes
- Nuclear Medicine Department, Clínica Universidad de Navarra, 31008 Pamplona, Spain
| | - Philipp Kaldis
- Department of Clinical Sciences, Lund University, Clinical Research Centre (CRC), P.O. Box 50332, SE-202 13 Malmö, Sweden
- Lund University Diabetes Centre (LUDC), Lund University, SE-202 13 Malmö, Sweden
| | - José Alfredo Martinez
- Department of Nutrition, Food Science and Physiology and Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Irunlarrea 1, 31008 Pamplona, Spain
| | - Gema Medina-Gómez
- Department of Basic Sciences of Health, Area of Biochemistry and Molecular Biology, Universidad Rey Juan Carlos, Alcorcon, 28933 Madrid, Spain
- LAFEMEX Laboratory, Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Spain
| | - María Jesús Moreno-Aliaga
- Department of Nutrition, Food Science and Physiology and Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Irunlarrea 1, 31008 Pamplona, Spain
- IdISNA—Navarra Institute for Health Research, 31008 Pamplona, Spain
- CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-948-425-600
| | - Xavier Escoté
- Department of Nutrition, Food Science and Physiology and Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Irunlarrea 1, 31008 Pamplona, Spain
- Eurecat, Centre Tecnològic de Catalunya, Unitat de Nutrició i Salut, 43204 Reus, Spain
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Ahmadpour S, Habibi MA, Hosseinimehr SJ. Various Aspects of Fasting on the Biodistribution of Radiopharmaceuticals. Curr Drug Metab 2022; 23:827-841. [PMID: 36121082 DOI: 10.2174/1389200223666220919121354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/08/2022] [Accepted: 07/30/2022] [Indexed: 01/11/2023]
Abstract
It is demonstrated that fasting can alter the biodistribution of radiopharmaceuticals in nuclear medicine. Various studies have highlighted that fasting is interpreted to be easy for physicians during PET study, fasting is one of the most important factors determining the usefulness of this protocol. It is well documented that fasting can suppress normal 18F-FDG PET uptake during nuclear cardiology. However, there is no consensus about the usefulness of fasting on radiopharmaceuticals, especially on 18F-FDG in PET imaging, but special attention should be paid to the setting of the fasting duration. Nevertheless, it does seem we still need extensive clinical studies in the future. The present study aims to review the various aspects of fasting, especially metabolic alteration on radiopharmaceutical biodistribution. In this study, we focused more on the effect of fasting on 18F-FDG biodistribution, which alters its imaging contrast in cardiology and cancer imaging. Therefore, shifting substrate metabolism from glucose to free fatty acids during fasting can be an alternative approach to suppress physiological myocardial uptake.
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Affiliation(s)
- Sajjad Ahmadpour
- Gastroenterology and Hepatology Diseases Research Center, Qom University of Medical Sciences, Qom, Iran
| | - Mohammad Amin Habibi
- Iranian Tissue Bank and Research Center, Gene, Cell and Tissue Institute, Tehran University of Medical Sciences, Tehran, Iran.,Clinical Research of Development Center, Beheshti Hospital, Qom University of Medical Sciences, Qom, Iran
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
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Li W, Ma J, Jiang Q, Zhang T, Qi Q, Cheng Y. Fast Noninvasive Measurement of Brown Adipose Tissue in Living Mice by Near-Infrared Fluorescence and Photoacoustic Imaging. Anal Chem 2020; 92:3787-3794. [PMID: 32066237 DOI: 10.1021/acs.analchem.9b05162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aberrant brown adipose tissue (BAT) metabolism is linked to obesity as well as other metabolic disorders. However, the paucity of imaging tools limits the study of in vivo BAT metabolism in animal models. The current work evaluated a heptamethine dye (CyHF-8) in living mice as a dual-modality BAT-avid molecular probe for two imaging approaches, including near-infrared fluorescence imaging (NIRF) and photoacoustic imaging (PAI). CyHF-8 exhibited favorable spectral properties in the near-infrared window (786/787/805 nm) and accumulated in the subcellular mitochondria of brown adipocytes. After intravenous injection of CyHF-8, NIRF and PAI were both capable of noninvasively detecting interscapular BAT at early time points in living mice. Quantitative analysis of NIRF and PAI images showed that CyHF-8 signals respond to dynamic BAT changes in mice stimulated by norepinephrine (NE) and in diabetic mice induced by streptozotocin (STZ). In summary, dual-modality NIRF/PAI probe CyHF-8 can be used for both NIRF and PAI to noninvasively assess BAT metabolism in living animals.
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Affiliation(s)
- Wanyun Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Jing Ma
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Qian Jiang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Ting Zhang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Qingrong Qi
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Yan Cheng
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
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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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Yang J, Yang J, Ran C. Spectral Unmixing Imaging for Differentiating Brown Adipose Tissue Mass and Its Activation. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:6134186. [PMID: 29531505 PMCID: PMC5817366 DOI: 10.1155/2018/6134186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/05/2017] [Accepted: 12/11/2017] [Indexed: 12/12/2022]
Abstract
Recent large-scale clinical analysis indicates that brown adipose tissue (BAT) mass levels inversely correlate with body-mass index (BMI), suggesting that BAT is associated with metabolic disorders such as obesity and diabetes. PET imaging with 18F-FDG is the most commonly used method for visualizing BAT. However, this method is not able to differentiate between BAT mass and BAT activation. This task, in fact, presents a tremendous challenge with no currently existing methods to separate BAT mass and BAT activation. Our previous results indicated that BAT could be successfully imaged in mice with near infrared fluorescent (NIRF) curcumin analogues. However, the results from conventional NIRF imaging could not reflect what portion of the NIRF signal from BAT activation contributed to the signal observed. To solve this problem, we used spectral unmixing to separate/unmix NIRF signal from oil droplets in BAT, which represents its mass and NIRF signal from blood, which represents BAT activation. In this report, results from our proof-of-concept investigation demonstrated that spectral unmixing could be used to separate NIRF signal from BAT mass and BAT activation.
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Affiliation(s)
- Jing Yang
- Molecular Imaging Laboratory, MGH/MIT/HMS 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
- School of Pharmacy, Soochow University, Suzhou 215006, China
| | - Jian Yang
- Molecular Imaging Laboratory, MGH/MIT/HMS 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
- Center for Drug Discovery, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Chongzhao Ran
- Molecular Imaging Laboratory, MGH/MIT/HMS 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
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Yang J, Yang J, Wang L, Moore A, Liang SH, Ran C. Synthesis-free PET imaging of brown adipose tissue and TSPO via combination of disulfiram and 64CuCl 2. Sci Rep 2017; 7:8298. [PMID: 28811616 PMCID: PMC5557754 DOI: 10.1038/s41598-017-09018-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/14/2017] [Indexed: 12/21/2022] Open
Abstract
PET imaging is a widely applicable but a very expensive technology. On-site synthesis is one important contributor to the high cost. In this report, we demonstrated the feasibility of a synthesis-free method for PET imaging of brown adipose tissue (BAT) and translocator protein 18 kDa (TSPO) via a combination of disulfiram, an FDA approved drug for alcoholism, and 64CuCl2 (termed 64Cu-Dis). In this method, a step-wise injection protocol of 64CuCl2 and disulfiram was used to accomplish the purpose of synthesis-free. Specifically, disulfiram, an inactive 64Cu ligand, was first injected to allow it to metabolize into diethyldithiocarbamate (DDC), a strong 64Cu ligand, which can chelate 64CuCl2 from the following injection to form the actual PET tracer in situ. Our blocking studies, western blot, and tissue histological imaging suggested that the observed BAT contrast was due to 64Cu-Dis binding to TSPO, which was further confirmed as a specific biomarker for BAT imaging using [18F]-F-DPA, a TSPO-specific PET tracer. Our studies, for the first time, demonstrated that TSPO could serve as a potential imaging biomarker for BAT. We believe that our strategy could be extended to other targets while significantly reducing the cost of PET imaging.
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Affiliation(s)
- Jing Yang
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, 01890, USA.,College of Pharmaceutical Sciences, Soochow University, Suzhou, 215006, China
| | - Jian Yang
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, 01890, USA.,School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Lu Wang
- Division of Nuclear Medicine and Molecular Imaging & Gordon Center for Medical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, 02114, USA
| | - Anna Moore
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, 01890, USA
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging & Gordon Center for Medical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, 02114, USA
| | - Chongzhao Ran
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, 01890, USA.
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Coleman RA, Liang C, Patel R, Ali S, Mukherjee J. Brain and Brown Adipose Tissue Metabolism in Transgenic Tg2576 Mice Models of Alzheimer Disease Assessed Using 18F-FDG PET Imaging. Mol Imaging 2017; 16:1536012117704557. [PMID: 28654383 PMCID: PMC5470140 DOI: 10.1177/1536012117704557] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/06/2017] [Accepted: 03/10/2017] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Imaging animal models of Alzheimer disease (AD) is useful for the development of therapeutic drugs and understanding AD. Transgenic Swedish hAPPswe Tg2576 mice are a good model of β-amyloid plaques. We report 18F-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET) imaging of brain and intrascapular brown adipose tissue (IBAT) in transgenic mice 2576 (Tg2576) and wild-type (WT) mice. METHODS Transgenic Tg2576 mice and WT mice, >18 months were injected intraperitonally with ≈ 25 to 30 MBq 18F-FDG while awake. After 60 minutes, they were anesthetized with isoflurane (2.5%) and imaged with Inveon MicroPET. Select mice were killed, imaged ex vivo, and 20 µm sections cut for autoradiography. 18F-FDG uptake in brain and IBAT PET and brain autoradiographs were analyzed. RESULTS Fasting blood glucose levels averaged 120 mg/dL for WT and 100 mg/dL for Tg2576. Compared to WT, Tg2576 mice exhibited a decrease in SUVglc in the various brain regions. Average reductions in the cerebrum regions were as high as -20%, while changes in cerebellum were -3%. Uptake of 18F-FDG in IBAT decreased by -60% in Tg2576 mice and was found to be significant. Intrascapular brown adipose tissue findings in Tg2576 mice are new and not previously reported. Use of blood glucose for PET data analysis and corpus callosum as reference region for autoradiographic analysis were important to detect change in Tg2576 mice. CONCLUSION Our results suggest that 18F-FDG uptake in the Tg2576 mice brain show 18F-FDG deficits only when blood glucose is taken into consideration.
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Affiliation(s)
- Robert A. Coleman
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA, USA
| | - Christopher Liang
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA, USA
| | - Rima Patel
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA, USA
| | - Sarah Ali
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA, USA
| | - Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA, USA
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Han C, Rice MW, Cai D. Neuroinflammatory and autonomic mechanisms in diabetes and hypertension. Am J Physiol Endocrinol Metab 2016; 311:E32-41. [PMID: 27166279 PMCID: PMC4967151 DOI: 10.1152/ajpendo.00012.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
Interdisciplinary studies in the research fields of endocrinology and immunology show that obesity-associated overnutrition leads to neuroinflammatory molecular changes, in particular in the hypothalamus, chronically causing various disorders known as elements of metabolic syndrome. In this process, neural or hypothalamic inflammation impairs the neuroendocrine and autonomic regulation of the brain over blood pressure and glucose homeostasis as well as insulin secretion, and elevated sympathetic activation has been appreciated as a critical mediator. This review describes the involved physiology and mechanisms, with a focus on glucose and blood pressure balance, and suggests that neuroinflammation employs the autonomic nervous system to mediate the development of diabetes and hypertension.
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Affiliation(s)
- Cheng Han
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
| | - Matthew W Rice
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
| | - Dongsheng Cai
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
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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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Kooijman S, van den Heuvel JK, Rensen PCN. Neuronal Control of Brown Fat Activity. Trends Endocrinol Metab 2015; 26:657-668. [PMID: 26482876 DOI: 10.1016/j.tem.2015.09.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/18/2015] [Accepted: 09/18/2015] [Indexed: 12/25/2022]
Abstract
Brown adipose tissue (BAT) activation reduces body fat and metabolic disorders by the enhanced combustion of lipids and glucose into heat. The thermogenic activity of brown adipocytes is primarily driven by the sympathetic nervous system (SNS) and controlled by the brain. In this review, we present recent advances in understanding how cues, such as temperature, light, and proteins, modulate the activity of brown fat by acting on the various hypothalamic nuclei. Given that activated BAT has a high capacity to take up and burn fatty acids (FAs) and glucose, pharmacological stimulation of brown fat in humans by either targeting the hypothalamus or mimicking outflow of the sympathetic nervous system might help improve glucose metabolism and insulin sensitivity, and also lower body fat.
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Affiliation(s)
- Sander Kooijman
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - José K van den Heuvel
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - Patrick C N Rensen
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands.
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Harrell R, Speaker HA, Mitchell SL, Sabol KE. The effects of the β1 antagonist, metoprolol, on methamphetamine-induced changes in core temperature in the rat. Neurosci Lett 2015; 609:81-6. [PMID: 26388403 DOI: 10.1016/j.neulet.2015.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 01/26/2023]
Abstract
Methamphetamine (METH) results in hyperthermia or hypothermia depending on environmental conditions. Here we studied the role of the β1 adrenergic receptor in mediating METH's temperature effects. Core temperature measurements were made telemetrically over a 7.5h session, two days/week, in test chambers regulated at either 18°C, 24°C, or 30°C ambient temperature. Rats were treated with the β1 antagonist metoprolol (5.0, 10.0, and 15.0mg/kg) alone (Experiment 1), or in combination with 5.0mg/kg METH (Experiment 2). In experiment 3, we combined a lower dose range of metoprolol (0.75, 1.5, and 3.0mg/kg) with 5.0mg/kg METH at 18°C and 30°C. Confirming prior findings, METH alone resulted in hyperthermia in warm (30°) and hypothermia in cool environments (18°C). Metoprolol alone induced small but significant increases in core temperature. In combination, however, metoprolol reduced METH-induced changes in core temperature. Specifically, at 30°C, 3.0, 5.0, 10.0, and 15.0mg/kg metoprolol decreased METH-induced hyperthermia; at 18°C, all six doses of metoprolol enhanced METH-induced hypothermia. Our metoprolol findings suggest that one component of METH's temperature effects involves increasing core temperature at all ambient conditions via β1 receptors. Since β receptors are involved in brown adipose tissue (BAT)-mediated thermogenesis, skeletal muscle-mediated thermogenesis, heart rate, and the metabolism of glucose and lipids, we discuss each of these as possible mechanisms for metoprolol's effects on METH-induced changes in core temperature.
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Affiliation(s)
- Ricki Harrell
- Department of Psychology, University of Mississippi, University, MS 38677, USA
| | - H Anton Speaker
- Department of Psychology, University of Mississippi, University, MS 38677, USA
| | - Scott L Mitchell
- Department of Psychology, University of Mississippi, University, MS 38677, USA
| | - Karen E Sabol
- Department of Psychology, University of Mississippi, University, MS 38677, USA.
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Zhang X, Tian Y, Zhang H, Kavishwar A, Lynes M, Brownell AL, Sun H, Tseng YH, Moore A, Ran C. Curcumin analogues as selective fluorescence imaging probes for brown adipose tissue and monitoring browning. Sci Rep 2015; 5:13116. [PMID: 26269357 PMCID: PMC4534785 DOI: 10.1038/srep13116] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 07/16/2015] [Indexed: 01/10/2023] Open
Abstract
Manipulation of brown adipose tissue (BAT) and browning of white adipose tissue (WAT) can be promising new approaches to counter metabolic disorder diseases in humans. Imaging probes that could consistently monitor BAT mass and browning of WAT are highly desirable. In the course of our imaging probe screening, we found that BAT could be imaged with curcumin analogues in mice. However, the poor BAT selectivity over WAT and short emissions of the lead probes promoted further lead optimization. Limited uptake mechanism studies suggested that CD36/FAT (fatty acid transporter) probably contributed to the facilitated uptake of the probes. By increasing the stereo-hindrance of the lead compound, we designed CRANAD-29 to extend the emission and increase the facilitated uptake, thus increasing its BAT selectivity. Our data demonstrated that CRANAD-29 had significantly improved selectivity for BAT over WAT, and could be used for imaging BAT mass change in a streptozotocin-induced diabetic mouse model, as well as for monitoring BAT activation under cold exposure. In addition, CRANAD-29 could be used for monitoring the browning of subcutaneous WAT (sWAT) induced by β3-adrenoceptor agonist CL-316, 243.
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Affiliation(s)
- Xueli Zhang
- 1] Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA [2] School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China [3] Department of pharmacy, ZhongDa Hospital, Southeast University, Nanjing 210009, China
| | - Yanli Tian
- 1] Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA [2] Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Hongbin Zhang
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Amol Kavishwar
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Matthew Lynes
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Anna-Liisa Brownell
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Hongbin Sun
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yu-Hua Tseng
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Anna Moore
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Chongzhao Ran
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
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13
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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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Kang F, Ma W, Ma X, Shao Y, Yang W, Chen X, Li L, Wang J. Propranolol inhibits glucose metabolism and 18F-FDG uptake of breast cancer through posttranscriptional downregulation of hexokinase-2. J Nucl Med 2014; 55:439-45. [PMID: 24504055 DOI: 10.2967/jnumed.113.121327] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED The advancement of breast cancer therapy is limited by the biologic behaviors of cancer cells, such as metastasis and recurrence. β-adrenoceptors (ADRB) are reported to be associated with the biologic behaviors of breast cancer and may influence glucose metabolism. Here, we sought to investigate the relationship between the activation of ADRB and the expression of glucose transporter (GLUT)-1 and hexokinase (HK)-2 and to clarify the impact of ADRB on (18)F-FDG PET imaging in breast cancer. METHODS ADRB1/2 expression in 4T1, MDA-MB-231, and MCF-7 breast cancer cell lines was detected by Western blotting and immunofluorescence. ADRB-dependent regulation of GLUT-1 and HK-2 was determined by in vitro pharmacologic intervention. 4T1 breast cancer cells were treated with phosphate-buffered saline, isoproterenol, or propranolol, and the transcription and expression of GLUT-1 and HK-2 were measured by quantitative real-time polymerase chain reaction (RT-PCR) and Western blotting, respectively. ADRB1/2 was, respectively, blocked by small-interfering RNA to investigate the direct relationship between ADRB1/2 and HK-2. To evaluate the impact of ADRB on (18)F-FDG PET imaging, BALB/c mice bearing 4T1 tumors were injected with phosphate-buffered saline, isoproterenol, or propranolol, and (18)F-FDG PET imaging was performed. The tumor-to-nontumor (T/NT) values of tumors and brown adipose tissue were calculated by defining the liver as a reference. The in vivo expression of GLUT-1 and HK-2 was observed by immunohistochemical analysis and Western blotting. RESULTS MDA-MB-231, MCF-7, and 4T1 breast cancer cells were positive for ADRB1/2 expression. The protein expression and posttranscriptional level of HK-2 were significantly decreased by treatment with propranolol in vitro, whereas GLUT-1 expression was not significantly altered by pharmacologic intervention. The expression of HK-2 could be reduced in ADRB2-blocked 4T1 cells. Mice in the propranolol-treated group exhibited lower T/NT values for the tumors and brown adipose tissue than the control group. Immunohistochemical analysis and Western blotting revealed reduced HK-2 expression in the tumors of propranolol-treated mice. CONCLUSION The expression of HK-2 was regulated by the activation of ADRB2 in 4T1 breast cancer cells primarily at the posttranscriptional level. Additionally, propranolol prevented glucose metabolism and (18)F-FDG PET imaging of 4T1 breast cancer tumors.
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Affiliation(s)
- Fei Kang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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15
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Vijgen GHEJ, Bouvy ND, Leenen L, Rijkers K, Cornips E, Majoie M, Brans B, van Marken Lichtenbelt WD. Vagus nerve stimulation increases energy expenditure: relation to brown adipose tissue activity. PLoS One 2013; 8:e77221. [PMID: 24194874 PMCID: PMC3806746 DOI: 10.1371/journal.pone.0077221] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 08/30/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Human brown adipose tissue (BAT) activity is inversely related to obesity and positively related to energy expenditure. BAT is highly innervated and it is suggested the vagus nerve mediates peripheral signals to the central nervous system, there connecting to sympathetic nerves that innervate BAT. Vagus nerve stimulation (VNS) is used for refractory epilepsy, but is also reported to generate weight loss. We hypothesize VNS increases energy expenditure by activating BAT. METHODS AND FINDINGS Fifteen patients with stable vns therapy (age: 45 ± 10 yrs; body mass index; 25.2 ± 3.5 kg/m(2)) were included between January 2011 and June 2012. Ten subjects were measured twice, once with active and once with inactivated VNS. Five other subjects were measured twice, once with active VNS at room temperature and once with active VNS under cold exposure in order to determine maximal cold-induced BAT activity. BAT activity was assessed by 18-Fluoro-Deoxy-Glucose-Positron-Emission-Tomography-and-Computed-Tomography. Basal metabolic rate (BMR) was significantly higher when VNS was turned on (mean change; +2.2%). Mean BAT activity was not significantly different between active VNS and inactive VNS (BAT SUV(Mean); 0.55 ± 0.25 versus 0.67 ± 0.46, P = 0.619). However, the change in energy expenditure upon VNS intervention (On-Off) was significantly correlated to the change in BAT activity (r = 0.935, P<0.001). CONCLUSIONS VNS significantly increases energy expenditure. The observed change in energy expenditure was significantly related to the change in BAT activity. This suggests a role for BAT in the VNS increase in energy expenditure. Chronic VNS may have a beneficial effect on the human energy balance that has potential application for weight management therapy. TRIAL REGISTRATION The study was registered in the Clinical Trial Register under the ClinicalTrials.gov Identifier NCT01491282.
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Affiliation(s)
- Guy H. E. J. Vijgen
- Department of Human Biology, School for Nutrition, Toxicology and Metabolism – NUTRIM, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of General Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Nicole D. Bouvy
- Department of General Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Loes Leenen
- Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - Kim Rijkers
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Erwin Cornips
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Marian Majoie
- Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - Boudewijn Brans
- Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Wouter D. van Marken Lichtenbelt
- Department of Human Biology, School for Nutrition, Toxicology and Metabolism – NUTRIM, Maastricht University Medical Center, Maastricht, The Netherlands
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Zhang X, Kuo C, Moore A, Ran C. In vivo optical imaging of interscapular brown adipose tissue with (18)F-FDG via Cerenkov luminescence imaging. PLoS One 2013; 8:e62007. [PMID: 23637947 PMCID: PMC3634850 DOI: 10.1371/journal.pone.0062007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 03/16/2013] [Indexed: 01/21/2023] Open
Abstract
Objective Brown adipose tissue (BAT), a specialized tissue for thermogenesis, plays important roles for metabolism and energy expenditure. Recent studies validated BAT’s presence in human adults, making it an important re-emerging target for various pathologies. During this validation, PET images with 18F-FDG showed significant uptake of 18F-FDG by BAT under certain conditions. Here, we demonstrated that Cerenkov luminescence imaging (CLI) using 18F-FDG could be utilized for in vivo optical imaging of BAT in mice. Methods Mice were injected with 18F-FDG and imaged 60 minutes later with open filter and 2 minute acquisition. In vivo activation of BAT was performed by norepinephrine and cold treatment under isoflurane or ketamine anesthesia. Spectral unmixing and 3D imaging reconstruction were conducted with multiple-filter CLI images. Results 1) It was feasible to use CLI with 18F-FDG to image interscapular BAT in mice, with the majority of the signal (>85%) at the interscapular site originating from BAT; 2) The method was reliable because excellent correlations between in vivo CLI, ex vivo CLI, and ex vivo radioactivity were observed; 3) CLI could be used for monitoring BAT activation under different conditions; 4) CLI signals from the group under short-term isoflurane anesthesia were significantly higher than that from the group under long-term anesthesia; 5) The CLI spectrum of 18F-FDG with a peak at 640 nm in BAT after spectral unmixing reflected the actual context of BAT; 6) Finally 3D reconstruction images showed excellent correlation between the source of the light signal and the location and physical shape of BAT. Conclusion CLI with 18F-FDG is a feasible and reliable method for imaging BAT in mice. Compared to PET imaging, CLI is significantly cheaper, faster for 2D planar imaging and easier to use. We believe that this method could be used as an important tool for researchers investigating BAT.
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Affiliation(s)
- Xueli Zhang
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts, United States of America
- Center for Drug Discovery, School of Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Chaincy Kuo
- Caliper, a Perkin Elmer Company, Alameda, California, United States of America
| | - Anna Moore
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts, United States of America
- * E-mail: (CR); (AM)
| | - Chongzhao Ran
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts, United States of America
- * E-mail: (CR); (AM)
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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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