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Carpentier AC. Tracers and Imaging of Fatty Acid and Energy Metabolism of Human Adipose Tissues. Physiology (Bethesda) 2024; 39:0. [PMID: 38113392 DOI: 10.1152/physiol.00012.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/22/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023] Open
Abstract
White adipose tissue and brown adipose tissue (WAT and BAT) regulate fatty acid metabolism and control lipid fluxes to other organs. Dysfunction of these key metabolic processes contributes to organ insulin resistance and inflammation leading to chronic diseases such as type 2 diabetes, metabolic dysfunction-associated steatohepatitis, and cardiovascular diseases. Metabolic tracers combined with molecular imaging methods are powerful tools for the investigation of these pathogenic mechanisms. Herein, I review some of the positron emission tomography and magnetic resonance imaging methods combined with stable isotopic metabolic tracers to investigate fatty acid and energy metabolism, focusing on human WAT and BAT metabolism. I will discuss the complementary strengths offered by these methods for human investigations and current gaps in the field.
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Affiliation(s)
- André C Carpentier
- Department of Medicine, Division of Endocrinology, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Ye RZ, Montastier É, Noll C, Frisch F, Fortin M, Bouffard L, Phoenix S, Guérin B, Turcotte ÉE, Carpentier AC. Total Postprandial Hepatic Nonesterified and Dietary Fatty Acid Uptake Is Increased and Insufficiently Curbed by Adipose Tissue Fatty Acid Trapping in Prediabetes With Overweight. Diabetes 2022; 71:1891-1901. [PMID: 35748318 PMCID: PMC9862339 DOI: 10.2337/db21-1097] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 06/14/2022] [Indexed: 02/05/2023]
Abstract
Excessive lean tissue uptake of fatty acids (FAs) is important in the development of insulin resistance and may be caused by impaired dietary FA (DFA) storage and/or increased nonesterified FA (NEFA) flux from adipose tissue intracellular lipolysis. Cardiac and hepatic total postprandial FA uptake of NEFA+DFA has, however, never been reported in prediabetes with overweight. In this study, 20 individuals with impaired glucose tolerance (IGT) and 19 participants with normal glucose tolerance (NGT) and normal fasting glucose underwent postprandial studies with whole-body positron emission tomography/computed tomography (PET/CT) with oral [18F]fluoro-thia-heptadecanoic acid and dynamic PET/CT with intravenous [11C]palmitate. Hepatic (97 [range 36-215] mmol/6 h vs. 68 [23-132] mmol/6 h, P = 0.03) but not cardiac (11 [range 4-24] mmol/6 h vs. 8 [3-20] mmol/6 h, P = 0.09) uptake of most sources of postprandial FA (NEFA + DFA uptake) integrated over 6 h was higher in IGT versus NGT. DFA accounted for lower fractions of total cardiac (21% [5-47] vs. 25% [9-39], P = 0.08) and hepatic (19% [6-52] vs. 28% [14-50], P = 0.04) uptake in IGT versus NGT. Increased adipose tissue DFA trapping predicted lower hepatic DFA uptake and was associated with higher total cardiac FA uptake. Hence, enhanced adipose tissue DFA trapping in the face of increased postprandial NEFA flux is insufficient to fully curb increased postprandial lean organ FA uptake in prediabetes with overweight (ClinicalTrials.gov; NCT02808182).
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Affiliation(s)
- Run Zhou Ye
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Émilie Montastier
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frédérique Frisch
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mélanie Fortin
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Lucie Bouffard
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Serge Phoenix
- Department of Nuclear Medicine and Radiobiology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Éric E. Turcotte
- Department of Nuclear Medicine and Radiobiology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - André C. Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Corresponding author: André C. Carpentier,
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Ye RZ, Richard G, Gévry N, Tchernof A, Carpentier AC. Fat Cell Size: Measurement Methods, Pathophysiological Origins, and Relationships With Metabolic Dysregulations. Endocr Rev 2022; 43:35-60. [PMID: 34100954 PMCID: PMC8755996 DOI: 10.1210/endrev/bnab018] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Indexed: 11/19/2022]
Abstract
The obesity pandemic increasingly causes morbidity and mortality from type 2 diabetes, cardiovascular diseases and many other chronic diseases. Fat cell size (FCS) predicts numerous obesity-related complications such as lipid dysmetabolism, ectopic fat accumulation, insulin resistance, and cardiovascular disorders. Nevertheless, the scarcity of systematic literature reviews on this subject is compounded by the use of different methods by which FCS measurements are determined and reported. In this paper, we provide a systematic review of the current literature on the relationship between adipocyte hypertrophy and obesity-related glucose and lipid dysmetabolism, ectopic fat accumulation, and cardiovascular disorders. We also review the numerous mechanistic origins of adipocyte hypertrophy and its relationship with metabolic dysregulation, including changes in adipogenesis, cell senescence, collagen deposition, systemic inflammation, adipokine secretion, and energy balance. To quantify the effect of different FCS measurement methods, we performed statistical analyses across published data while controlling for body mass index, age, and sex.
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Affiliation(s)
- Run Zhou Ye
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Gabriel Richard
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Nicolas Gévry
- Department of Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - André Tchernof
- Québec Heart and Lung Research Institute, Laval University, Québec, Québec, Canada
| | - André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
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Després JP, Carpentier AC, Tchernof A, Neeland IJ, Poirier P. Management of Obesity in Cardiovascular Practice: JACC Focus Seminar. J Am Coll Cardiol 2021; 78:513-531. [PMID: 34325840 PMCID: PMC8609918 DOI: 10.1016/j.jacc.2021.05.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/14/2022]
Abstract
Obesity contributes to reduced life expectancy because of its link with type 2 diabetes and cardiovascular disease. Yet, targeting this poorly diagnosed, ill-defined, and underaddressed modifiable risk factor remains a challenge. In this review, we emphasize that the tendency among health care professionals to amalgam all forms of obesity altogether as a single entity may contribute to such difficulties and discrepancies. Obesity is a heterogeneous condition both in terms of causes and health consequences. Attention should be given to 2 prevalent subgroups of individuals: 1) patients who are overweight or moderately obese with excess visceral adipose tissue; and 2) patients with severe obesity, the latter group having distinct additional health issues related to their large body fat mass. The challenge of tackling high-cardiovascular-risk forms of obesity through a combination of personalized clinical approaches and population-based solutions is compounded by the current obesogenic environment and economy.
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Affiliation(s)
- Jean-Pierre Després
- VITAM-Centre de recherche en santé durable, CIUSSS de la Capitale-Nationale, Québec, Québec, Canada; Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Québec, Canada; Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Québec, Canada.
| | - André C Carpentier
- Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, Québec, Canada; Department of Medicine, Division of Endocrinology, Université de Sherbrooke, Sherbrooke, Québec, Canada. https://twitter.com/CarpentierAndr3
| | - André Tchernof
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Québec, Canada; School of Nutrition, Université Laval, Québec, Québec, Canada
| | - Ian J Neeland
- University Hospitals Harrington Heart and Vascular Institute and Case Western Reserve University, Cleveland, Ohio, USA
| | - Paul Poirier
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Québec, Canada; Faculty of Pharmacy, Université Laval, Québec, Québec, Canada
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Walhin JP, Gonzalez JT, Betts JA. Physiological responses to carbohydrate overfeeding. Curr Opin Clin Nutr Metab Care 2021; 24:379-384. [PMID: 33871420 DOI: 10.1097/mco.0000000000000755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW To consider emerging research into the physiological effects of excessive dietary carbohydrate intake, with a particular focus on interactions with physical activity. RECENT FINDINGS A single episode of massive carbohydrate overload initiates physiological responses to stimulate additional peptide hormone secretion by the gut and the conversion of carbohydrate into lipid by the intestine, liver and adipose tissue. These acute responses maintain glycaemic control both via increased oxidation of carbohydrate (rather than lipid) and via nonoxidative disposal of surplus carbohydrate into endogenous glycogen and lipid storage depots. Sustained carbohydrate overfeeding therefore results in a chronic accumulation of lipid in the liver, skeletal muscle and adipose tissue, which can impair insulin sensitivity and cardiometabolic health in general. Beyond any direct effect of such lipid deposition on body mass/composition, there is not yet clear evidence of physiologically meaningful metabolic or behavioural adaptations to carbohydrate overfeeding in terms of other components of energy balance. However, regular physical exercise can mitigate the negative health effects of carbohydrate overfeeding, independent of any effect on the net carbohydrate surplus. SUMMARY Research in this area has advanced understanding regarding the mechanisms of weight gain and associated health outcomes within the modern context of an abundant supply of dietary carbohydrate.
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Affiliation(s)
- Jean-Philippe Walhin
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, UK
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Montastier É, Ye RZ, Noll C, Bouffard L, Fortin M, Frisch F, Phoenix S, Guérin B, Turcotte ÉE, Lewis GF, Carpentier AC. Increased postprandial nonesterified fatty acid efflux from adipose tissue in prediabetes is offset by enhanced dietary fatty acid adipose trapping. Am J Physiol Endocrinol Metab 2021; 320:E1093-E1106. [PMID: 33870714 DOI: 10.1152/ajpendo.00619.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mechanism of increased postprandial nonesterified fatty acid (NEFA) appearance in the circulation in impaired glucose tolerance (IGT) is due to increased adipose tissue lipolysis but could also be contributed to by reduced adipose tissue (AT) dietary fatty acid (DFA) trapping and increased "spillover" into the circulation. Thirty-one subjects with IGT (14 women, 17 men) and 29 with normal glucose tolerance (NGT, 15 women, 14 men) underwent a meal test with oral and intravenous palmitate tracers and the oral [18F]-fluoro-thia-heptadecanoic acid positron emission tomography method. Postprandial palmitate appearance (Rapalmitate) was higher in IGT versus NGT (P < 0.001), driven exclusively by Rapalmitate from obesity-associated increase in intracellular lipolysis (P = 0.01), as Rapalmitate from DFA spillover was not different between the groups (P = 0.19) and visceral AT DFA trapping was even higher in IGT versus NGT (P = 0.02). Plasma glycerol appearance was lower in IGT (P = 0.01), driven down by insulin resistance and increased insulin secretion. Thus, we found higher AT DFA trapping, limiting spillover to lean organs and in part offsetting the increase in Rapalmitate from intracellular lipolysis. Whether similar findings occur in frank diabetes, a condition also characterized by insulin resistance but relative insulin deficiency, requires further investigation (Clinicaltrials.gov: NCT04088344, NCT02808182).NEW & NOTEWORTHY We found higher adipose tissue dietary fatty acid trapping, limiting spillover to lean organs, that in part offsets the increase in appearance rate of palmitate from intracellular lipolysis in prediabetes. These results point to the adaptive nature of adipose tissue trapping and dietary fatty acid spillover as a protective mechanism against excess obesity-related palmitate appearance rate from intracellular adipose tissue lipolysis.
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Affiliation(s)
- Émilie Montastier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Run Zhou Ye
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Lucie Bouffard
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mélanie Fortin
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frédérique Frisch
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | | | - Brigitte Guérin
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Éric E Turcotte
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Gary F Lewis
- Division of Endocrinology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Carpentier AC. 100 th anniversary of the discovery of insulin perspective: insulin and adipose tissue fatty acid metabolism. Am J Physiol Endocrinol Metab 2021; 320:E653-E670. [PMID: 33522398 DOI: 10.1152/ajpendo.00620.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin inhibits systemic nonesterified fatty acid (NEFA) flux to a greater degree than glucose or any other metabolite. This remarkable effect is mainly due to insulin-mediated inhibition of intracellular triglyceride (TG) lipolysis in adipose tissues and is essential to prevent diabetic ketoacidosis, but also to limit the potential lipotoxic effects of NEFA in lean tissues that contribute to the development of diabetes complications. Insulin also regulates adipose tissue fatty acid esterification, glycerol and TG synthesis, lipogenesis, and possibly oxidation, contributing to the trapping of dietary fatty acids in the postprandial state. Excess NEFA flux at a given insulin level has been used to define in vivo adipose tissue insulin resistance. Adipose tissue insulin resistance defined in this fashion has been associated with several dysmetabolic features and complications of diabetes, but the mechanistic significance of this concept is not fully understood. This review focusses on the in vivo regulation of adipose tissue fatty acid metabolism by insulin and the mechanistic significance of the current definition of adipose tissue insulin resistance. One hundred years after the discovery of insulin and despite decades of investigations, much is still to be understood about the multifaceted in vivo actions of this hormone on adipose tissue fatty acid metabolism.
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Affiliation(s)
- André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Richard G, Noll C, Archambault M, Lebel R, Tremblay L, Ait-Mohand S, Guérin B, Blondin DP, Carpentier AC, Lepage M. Contribution of perfusion to the 11 C-acetate signal in brown adipose tissue assessed by DCE-MRI and 68 Ga-DOTA PET in a rat model. Magn Reson Med 2020; 85:1625-1642. [PMID: 33010059 DOI: 10.1002/mrm.28535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/15/2020] [Accepted: 09/07/2020] [Indexed: 12/29/2022]
Abstract
PURPOSE Determine if dynamic contrast enhanced (DCE) -MRI and/or 68 gallium 1,4,7,10-tetraazacyclododecane N, N', N″, N‴-tretraacetic acid (68 Ga-DOTA) positron emission tomography (PET) can assess perfusion in rat brown adipose tissue (BAT). Evaluate changes in perfusion between cold-stimulated and heat-inhibited BAT. Determine if the 11 C-acetate pharmacokinetic model can be constrained with perfusion information to improve assessment of BAT oxidative metabolism. METHODS Rats were split into three groups. In group 1 (N = 6), DCE-MRI with gadobutrol was compared directly to 68 Ga-DOTA PET following exposure to 10 °C for 48 h. 11 C-Acetate PET was also performed to assess oxidation. In group 2 (N = 4), only 68 Ga-DOTA PET was acquired following exposure to 10 °C for 48 h. Finally, in group 3 (N = 10), perfusion was assessed with DCE-MRI in rats exposed to 10 °C or 30 °C for 48 h, and oxidation was measured with 11 C-acetate. Perfusion was quantified with a two-compartment pharmacokinetic model, while oxidation was assessed by a four-compartment model. RESULTS DCE-MRI and 68 Ga-DOTA PET provided similar perfusion measures, but a decrease in the perfusion signal was noted with longer imaging sessions. Exposure to 10 °C or 30 °C did not affect the perfusion measures, but the 11 C-acetate signal increased in BAT at 10 °C. Without prior information about blood volume, the 11 C-acetate compartment model overestimated blood volume and underestimated oxidation in 10 °C BAT. CONCLUSION Precise assessment of oxidation via 11 C-acetate PET requires prior information about blood volume which can be obtained by DCE-MRI or 68 Ga-DOTA PET. Since perfusion can change rapidly, simultaneous PET-MRI would be preferred.
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Affiliation(s)
- Gabriel Richard
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mélanie Archambault
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Réjean Lebel
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Luc Tremblay
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Samia Ait-Mohand
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Brigitte Guérin
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Denis P Blondin
- Division of Neurology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Martin Lepage
- Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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