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Paulus A, Maenen M, Drude N, Nascimento EBM, van Marken Lichtenbelt WD, Mottaghy FM, Bauwens M. Synthesis, radiosynthesis and in vitro evaluation of 18F-Bodipy-C16/triglyceride as a dual modal imaging agent for brown adipose tissue. PLoS One 2017; 12:e0182297. [PMID: 28817670 PMCID: PMC5560730 DOI: 10.1371/journal.pone.0182297] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/15/2017] [Indexed: 11/18/2022] Open
Abstract
Background Brown adipose tissue research is in the focus in the field of endocrinology. We designed a dual-modal fluorescent/PET fatty acid based tracer on commercially available Bodipy-C16, which can be synthesized to its corresponding triglyceride and which combines the benefits of fluorescent and PET imaging. Methods Bodipy-C16 was coupled to 1,3-diolein resulting in Bodipy-triglyceride. Bodipy-C16 and Bodipy-triglyceride compounds were radiolabeled with 18F using an 18F/19F exchange reaction to yield a dual-modal imaging molecule. Uptake of radiolabeled and non-labeled Bodipy-C16 and Bodipy-triglyceride was analyzed by fluorescence imaging and radioactive uptake in cultured adipocytes derived from human brown adipose tissue and white adipose tissue. Results Bodipy-C16 and Bodipy-triglyceride were successfully radiolabeled and Bodipy-C16 showed high shelf life and blood plasma stability (99% from 0–4 h). The uptake of Bodipy-C16 increased over time in cultured adipocytes, which was further enhanced after beta-adrenergic stimulation with norepinephrine. The uptake of Bodipy-C16 was inhibited by oleic acid and CD36 inhibitor sulfosuccinimidyl-oleate. The poor solubility of Bodipy-triglyceride did not allow stability or in vitro experiments. Conclusion The new developed dual modal fatty acid based tracers Bodipy-C16 and Bodipy-triglyceride showed promising results to stimulate further in vivo evaluation and will help to understand brown adipose tissues role in whole body energy expenditure.
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Te Kulve M, Schlangen LJM, Schellen L, Frijns AJH, van Marken Lichtenbelt WD. The impact of morning light intensity and environmental temperature on body temperatures and alertness. Physiol Behav 2017; 175:72-81. [PMID: 28366816 DOI: 10.1016/j.physbeh.2017.03.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 11/17/2022]
Abstract
Indoor temperature and light exposure are known to affect body temperature, productivity and alertness of building occupants. However, not much is known about the interaction between light and temperature exposure and the relationship between morning light induced alertness and its effect on body temperature. Light intensity and room temperature during morning office hours were investigated under strictly controlled conditions. In a randomized crossover study, two white light conditions (4000K, either bright 1200lx or dim 5lx) under three different room temperatures (26, 29 and 32°C) were investigated. A lower room temperature increased the core body temperature (CBT) and lowered skin temperature and the distal-proximal temperature gradient (DPG). Moreover, a lower room temperature reduced the subjective sleepiness and reaction time on an auditory psychomotor vigilance task (PVT), irrespective of the light condition. Interestingly, the morning bright light exposure did affect thermophysiological parameters, i.e. it decreased plasma cortisol, CBT and proximal skin temperature and increased the DPG, irrespective of the room temperature. During the bright light session, subjective sleepiness decreased irrespective of the room temperature. However, the change in sleepiness due to the light exposure was not related to these physiological changes.
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Schrauwen P, van Marken Lichtenbelt WD. Combatting type 2 diabetes by turning up the heat. Diabetologia 2016; 59:2269-2279. [PMID: 27591854 PMCID: PMC5506100 DOI: 10.1007/s00125-016-4068-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/22/2016] [Indexed: 12/21/2022]
Abstract
In our westernised society, the level of physical activity is low. Interventions that increase energy expenditure are generally associated with an improvement in metabolic health. Exercise and exercise training increase energy metabolism and are considered to be among the best strategies for prevention of type 2 diabetes mellitus. More recently, cold exposure has been suggested to have a therapeutic value in type 2 diabetes. At a cellular level, there is evidence that increasing the turnover of cellular substrates such as fatty acids is associated with preventive effects against lipid-induced insulin resistance. Cellular energy sensors may underlie the effects linking energy turnover with metabolic health effects. Here we review data supporting the hypothesis that increasing energy and substrate turnover has beneficial effects on insulin sensitivity and should be considered a target for the prevention and treatment of type 2 diabetes.
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Hanssen MJW, van der Lans AAJJ, Brans B, Hoeks J, Jardon KMC, Schaart G, Mottaghy FM, Schrauwen P, van Marken Lichtenbelt WD. Short-term Cold Acclimation Recruits Brown Adipose Tissue in Obese Humans. Diabetes 2016; 65:1179-89. [PMID: 26718499 DOI: 10.2337/db15-1372] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022]
Abstract
Recruitment of brown adipose tissue (BAT) has emerged as a potential tool to combat obesity and associated metabolic complications. Short-term cold acclimation has been shown not only to enhance the presence and activity of BAT in lean humans but also to improve the metabolic profile of skeletal muscle to benefit glucose uptake in patients with type 2 diabetes. Here we examined whether short-term cold acclimation also induced such adaptations in 10 metabolically healthy obese male subjects. A 10-day cold acclimation period resulted in increased cold-induced glucose uptake in BAT, as assessed by [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography. BAT activity was negatively related to age, with a similar trend for body fat percentage. In addition, cold-induced glucose uptake in BAT was positively related to glucose uptake in visceral white adipose tissue, although glucose uptake in visceral and subcutaneous white adipose tissue depots was unchanged upon cold acclimation. Cold-induced skeletal muscle glucose uptake tended to increase upon cold acclimation, which was paralleled by increased basal GLUT4 localization in the sarcolemma, as assessed through muscle biopsies. Proximal skin temperature was increased and subjective responses to cold were slightly improved at the end of the acclimation period. These metabolic adaptations to prolonged exposure to mild cold may lead to improved glucose metabolism or prevent the development of obesity-associated insulin resistance and hyperglycemia.
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Broeders EPM, Vijgen GHEJ, Havekes B, Bouvy ND, Mottaghy FM, Kars M, Schaper NC, Schrauwen P, Brans B, van Marken Lichtenbelt WD. Thyroid Hormone Activates Brown Adipose Tissue and Increases Non-Shivering Thermogenesis--A Cohort Study in a Group of Thyroid Carcinoma Patients. PLoS One 2016; 11:e0145049. [PMID: 26784028 PMCID: PMC4718641 DOI: 10.1371/journal.pone.0145049] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/26/2015] [Indexed: 11/19/2022] Open
Abstract
Background/Objectives Thyroid hormone receptors are present on brown adipose tissue (BAT), indicating a role for thyroid hormone in the regulation of BAT activation. The objective of this study was to examine the effect of thyroid hormone withdrawal followed by thyroid hormone in TSH-suppressive dosages, on energy expenditure and brown adipose tissue activity. Subjects/Methods This study was a longitudinal study in an academic center, with a follow-up period of 6 months. Ten patients with well-differentiated thyroid carcinoma eligible for surgical treatment and subsequent radioactive iodine ablation therapy were studied in a hypothyroid state after thyroidectomy and in a subclinical hyperthyroid state (TSH-suppression according to treatment protocol). Paired two-tailed t-tests and linear regression analyses were used. Results Basal metabolic rate (BMR) was significantly higher after treatment with synthetic thyroid hormone (levothyroxine) than in the hypothyroid state (BMR 3.8 ± 0.5 kJ/min versus 4.4 ± 0.6 kJ/min, P = 0.012), and non-shivering thermogenesis (NST) significantly increased from 15 ± 10% to 25 ± 6% (P = 0.009). Mean BAT activity was significantly higher in the subclinical hyperthyroid state than in the hypothyroid state (BAT standard uptake value (SUVMean) 4.0 ± 2.9 versus 2.4 ± 1.8, P = 0.039). Conclusions Our study shows that higher levels of thyroid hormone are associated with a higher level of cold-activated BAT. Trial Registration ClinicalTrials.gov NCT02499471
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Puar T, van Berkel A, Gotthardt M, Havekes B, Hermus ARMM, Lenders JWM, van Marken Lichtenbelt WD, Xu Y, Brans B, Timmers HJLM. Genotype-Dependent Brown Adipose Tissue Activation in Patients With Pheochromocytoma and Paraganglioma. J Clin Endocrinol Metab 2016; 101:224-32. [PMID: 26574955 DOI: 10.1210/jc.2015-3205] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Patients with pheochromocytomas and paragangliomas (PGLs) may have brown adipose tissue (BAT) activation induced by catecholamine excess. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) can be used for the localization of both PGLs and BAT. It is unknown whether BAT is specifically affected by altered cellular energy metabolism in patients with SDHx- and VHL-related PGLs. OBJECTIVE The objective of the study was to determine endocrine and paracrine effects of catecholamine excess on BAT activation in patients with PGLs as detected by (18)F-FDG PET/CT, taking into account genetic variation. DESIGN Patients with PGLs who were fully genetically characterized underwent presurgical (18)F-FDG PET/CT imaging for tumor localization and to quantify BAT activation. SETTING The study was conducted at a single Dutch tertiary referral center. PATIENTS AND INTERVENTION Seventy-three patients, aged 52.4 ± 15.4 years, with a body mass index of 25.2 ± 4.1 kg/m(2), mean ± SD, were grouped into sporadic, cluster 1 (SDHx, VHL) and cluster 2 (RET, NF1, MAX) mutations. MAIN OUTCOME MEASURES (18)F-FDG mean standard uptake values were assessed in predefined BAT locations, including perirenal fat. RESULTS Twenty-one of 73 patients (28.8%) exhibited BAT activation. BAT activation was absent in all six patients with nonsecreting PGLs. No difference in (18)F-FDG uptake by perirenal fat on the side of the pheochromocytoma and the contralateral side was observed (mean standard uptake value of 0.80 vs 0.78, respectively, P = .42). The prevalence of BAT activation did not differ between sporadic (28.9%), cluster 1 (40.0%), and cluster 2 patients (15.4%, P= .36). CONCLUSION Patients with PGLs exhibit a high prevalence of BAT activation on (18)F-FDG PET/CT. This is likely due to systemic catecholamine excess. BAT activation is not associated with specific germline mutations.
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Pallubinsky H, Schellen L, Kingma BRM, van Marken Lichtenbelt WD. Human thermoneutral zone and thermal comfort zone: effects of mild heat acclimation. EXTREME PHYSIOLOGY & MEDICINE 2015. [PMCID: PMC4580796 DOI: 10.1186/2046-7648-4-s1-a7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Dijk W, Heine M, Vergnes L, Boon MR, Schaart G, Hesselink MKC, Reue K, van Marken Lichtenbelt WD, Olivecrona G, Rensen PCN, Heeren J, Kersten S. ANGPTL4 mediates shuttling of lipid fuel to brown adipose tissue during sustained cold exposure. eLife 2015; 4. [PMID: 26476336 PMCID: PMC4709329 DOI: 10.7554/elife.08428] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 10/16/2015] [Indexed: 12/21/2022] Open
Abstract
Brown adipose tissue (BAT) activation via cold exposure is increasingly scrutinized as a potential approach to ameliorate cardio-metabolic risk. Transition to cold temperatures requires changes in the partitioning of energy substrates, re-routing fatty acids to BAT to fuel non-shivering thermogenesis. However, the mechanisms behind the redistribution of energy substrates to BAT remain largely unknown. Angiopoietin-like 4 (ANGPTL4), a protein that inhibits lipoprotein lipase (LPL) activity, is highly expressed in BAT. Here, we demonstrate that ANGPTL4 is part of a shuttling mechanism that directs fatty acids derived from circulating triglyceride-rich lipoproteins to BAT during cold. Specifically, we show that cold markedly down-regulates ANGPTL4 in BAT, likely via activation of AMPK, enhancing LPL activity and uptake of plasma triglyceride-derived fatty acids. In contrast, cold up-regulates ANGPTL4 in WAT, abolishing a cold-induced increase in LPL activity. Together, our data indicate that ANGPTL4 is an important regulator of plasma lipid partitioning during sustained cold. DOI:http://dx.doi.org/10.7554/eLife.08428.001 The body stores energy in the form of fat molecules. Most of these molecules are stored in white fat cells. Other fat cells, the so-called brown fat cells, consume fats and produce heat to maintain body temperature in cold conditions. The capacity of brown fat cells to consume fats has led researchers to investigate whether brown fat cells might be a key to combat obesity. When an organism is cold, fat is shuttled to the brown fat cells. An enzyme called lipoprotein lipase is involved in a process that allows these fat molecules to be taken up by brown fat cells. However, it was not clear exactly how this process works. A protein called Angiopoietin-like 4 (ANGPTL4) inhibits the activity of lipoprotein lipase in white fat cells and is also found at high levels in brown fat cells. Here, Dijk et al. used genetic and biochemical approaches to study the role of ANGPTL4 in the fat cells of mice. The experiments show that when mice are exposed to cold, the levels of ANGPTL4 decrease in the brown fat cells. This allows the activity of lipoprotein lipase to increase so that these cells are able to take up more fat molecules. However, the opposite happens in white fat cells during cold exposure. The levels of ANGPTL4 increase, which decreases the activity of lipoprotein lipase in white fat cells to allow fat molecules to be shuttled specifically to the brown fat cells. Further experiments suggest that the opposite regulation of ANGPTL4 in brown and white fat cells could be due to a protein called AMPK. This protein is found at higher levels in brown fat cells than in white fat cells and is produced by brown fat cells during cold exposure. Taken together, Dijk et al. show that organs and cells work together to ensure that fat molecules are appropriately distributed to cells in need of energy, such as to brown fat cells during cold. How these findings could be used to stimulate fat consumption by brown fat cells in humans remains open for further investigation. DOI:http://dx.doi.org/10.7554/eLife.08428.002
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Abstract
ASC-1, PAT2, and P2RX5 are newly identified cell-surface proteins that may distinguish brown/beige from white adipocytes in mouse and human adipose tissue (Ussar et al., this issue).
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van der Lans AAJJ, Vosselman MJ, Hanssen MJW, Brans B, van Marken Lichtenbelt WD. Supraclavicular skin temperature and BAT activity in lean healthy adults. J Physiol Sci 2015; 66:77-83. [PMID: 26420686 PMCID: PMC4676963 DOI: 10.1007/s12576-015-0398-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/30/2015] [Indexed: 11/28/2022]
Abstract
The 'gold standard' for measuring brown adipose tissue (BAT) in humans is [(18)F]FDG-PET/CT-imaging. With this technique subjects are exposed to ionizing radiation and are therefore limited in the number of scans that can be performed. We investigated the relation between supraclavicular skin temperatures and BAT activity values using a strictly temperature-controlled air-cooling protocol. Data of 36 male subjects was analyzed. BAT activity was evaluated by [(18)F]FDG-PET/CT-imaging and skin temperature was measured by means of wireless temperature sensors. Supraclavicular skin temperature dropped less compared to skin temperatures at other sites (all P values <0.01). A significant positive correlation was found between the change in supraclavicular skin temperature with BAT activity (R (2) 0.23), and the change in supraclavicular skin temperature and non-shivering thermogenesis (R (2) 0.18, both P values <0.01). The correlations indicate that supraclavicular skin temperature (changes) can potentially be used as a qualitative measure of BAT activity and BAT thermogenesis.
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Schrauwen P, van Marken Lichtenbelt WD, Spiegelman BM. The future of brown adipose tissues in the treatment of type 2 diabetes. Diabetologia 2015; 58:1704-7. [PMID: 25957230 DOI: 10.1007/s00125-015-3611-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/10/2015] [Indexed: 01/26/2023]
Abstract
The recent recognition that humans possess active depots of brown adipose tissue has boosted the interest in this tissue as a potential target for the prevention and treatment of obesity and related metabolic disorders. Furthermore, it was also revealed that brown adipose tissue (BAT) in humans may consist of so-called beige or brite adipocytes. So far, cold exposure is recognised as the strongest activator of BAT in humans, but there is much ongoing research focused on finding alternative activators of BAT. The consequences of long-term BAT activation and/or cold exposure on metabolic health are still unknown, and this represents an area of intensive research. This is one of a series of commentaries under the banner '50 years forward', giving personal opinions on future perspectives in diabetes, to celebrate the 50th anniversary of Diabetologia (1965-2015).
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van der Lans AAJJ, Boon MR, Haks MC, Quinten E, Schaart G, Ottenhoff TH, van Marken Lichtenbelt WD. Cold acclimation affects immune composition in skeletal muscle of healthy lean subjects. Physiol Rep 2015; 3:3/7/e12394. [PMID: 26149277 PMCID: PMC4552515 DOI: 10.14814/phy2.12394] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Low environmental temperatures have a profound effect on biological processes in the body, including the immune system. Cold exposure coincides with hormonal changes, which may directly or indirectly alter the immune system, even in the skeletal muscle. The aim of the present study was to investigate the effect of cold acclimation on immune composition in skeletal muscle. Skeletal muscle biopsies were obtained from 17 healthy lean subjects before and after 10 days of mild cold exposure (15 °: C, 6 h/day). Nonshivering thermogenesis was calculated by indirect calorimetry. We found that cold acclimation increased nonshivering thermogenesis from 10.8 ± 7.5 before to 17.8 ± 11.1% after cold acclimation (P < 0.01), but did not affect plasma catecholamine nor cytokine levels. In contrast, cold acclimation affected mRNA expression of several immune cell markers in skeletal muscle. It downregulated expression of the Th17 markers RORC (-28%, P < 0.01) and NEDD4L (-15%, P < 0.05), as well as the regulatory T-cell marker FOXP3 (-13%, P < 0.05). Furthermore, cold acclimation downregulated expression of the M2 macrophage markers CCL22 (-50%, P < 0.05), CXCL13 (-17%, P < 0.05) and CD209 (-15%, P < 0.05), while the M1 macrophage marker IL12B was upregulated (+141%, P < 0.05). Cold acclimation also enhanced several markers related to interferon (IFN) signaling, including TAP1 (+12%, P < 0.01), IFITM1/3 (+11%, P < 0.05), CD274 (+36%, P < 0.05) and STAT 2 (+10%, P < 0.05). In conclusion, 10 days of intermittent cold exposure induces marked changes in the expression of immune cell markers in skeletal muscle of healthy lean subjects. The physiological consequences and therapeutic relevance of these changes remain to be determined.
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Hanssen MJW, Broeders E, Samms RJ, Vosselman MJ, van der Lans AAJJ, Cheng CC, Adams AC, van Marken Lichtenbelt WD, Schrauwen P. Serum FGF21 levels are associated with brown adipose tissue activity in humans. Sci Rep 2015; 5:10275. [PMID: 25985218 PMCID: PMC4434994 DOI: 10.1038/srep10275] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/09/2015] [Indexed: 01/17/2023] Open
Abstract
The obesity pandemic has spurred a need for novel therapies to prevent and treat metabolic complications. The recent rediscovery of brown adipose tissue (BAT) in humans made this tissue a possible therapeutic target, due to its potentially substantial contributions to energy homeostasis. Fibroblast growth factor 21 (FGF21) has been identified as a facilitator of cold-induced thermogenesis in humans. Furthermore, pre-clinical studies revealed that FGF21 administration leads to improvement in the metabolic consequences of obesity, such as dyslipidemia and type 2 diabetes. Here we studied plasma FGF21 levels in two cohorts of human subjects, in whom BAT activity was determined using an individualized cooling protocol by [(18)F]FDG-PET/CT scan. Importantly, we found that circulating FGF21 levels correlated with BAT activity during acute cold exposure in male subjects. In addition, FGF21 levels were related to the change in core temperature upon acute cold exposure, indicating a role for FGF21 in maintaining normothermia, possibly via activation of BAT. Furthermore, cold acclimation increased BAT activity in parallel with increased FGF21 levels. In conclusion, our results demonstrate that FGF21 levels in humans are related to BAT activity, suggesting that FGF21 may represent a novel mechanism via which BAT activity in humans may be enhanced.
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Bucerius J, Vijgen GHEJ, Brans B, Bouvy ND, Bauwens M, Rudd JHF, Havekes B, Fayad ZA, van Marken Lichtenbelt WD, Mottaghy FM. Impact of bariatric surgery on carotid artery inflammation and the metabolic activity in different adipose tissues. Medicine (Baltimore) 2015; 94:e725. [PMID: 25997038 PMCID: PMC4602867 DOI: 10.1097/md.0000000000000725] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In this study, we unravel a molecular imaging marker correlated with the known reduction of cardiovascular events (most commonly related to vulnerable plaques) in morbidly obese patients after bariatric surgery (BaS).We prospectively imaged 10 morbidly obese subjects with F-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography before and 1 year after BaS. F-FDG uptake-which is enhanced in inflamed, atherosclerotic vessels and in metabolically active adipose tissues-was quantified in the carotids, pericardial adipose tissue (PAT), visceral adipose tissue (VAT), as well as brown adipose tissue (BAT). The degree of carotid inflammation was compared to lean and overweight controls.Carotid inflammation significantly declined leading to an F-FDG uptake comparable to the 2 control groups. Metabolic activity significantly decreased in PAT and VAT and increased in BAT.BaS leads to a normalization of carotid artery inflammation and a beneficial impact on the metabolic activity in PAT, VAT, and BAT that is related to the metabolic syndrome observed in this patient group.
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Hanssen MJW, Wierts R, Hoeks J, Gemmink A, Brans B, Mottaghy FM, Schrauwen P, van Marken Lichtenbelt WD. Glucose uptake in human brown adipose tissue is impaired upon fasting-induced insulin resistance. Diabetologia 2015; 58:586-95. [PMID: 25500952 DOI: 10.1007/s00125-014-3465-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 11/17/2014] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Human brown adipose tissue (BAT) has recently emerged as a potential target in the treatment of type 2 diabetes, owing to its capacity to actively clear glucose from the circulation—at least upon cold exposure. The effects of insulin resistance on the capacity of human BAT to take up glucose are unknown. Prolonged fasting is known to induce insulin resistance in peripheral tissues in order to spare glucose for the brain. METHODS We studied the effect of fasting-induced insulin resistance on the capacity of BAT to take up glucose during cold exposure as well as on cold-stimulated thermogenesis. BAT glucose uptake was assessed by means of cold-stimulated dynamic 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography ([(18)F]FDG-PET/CT) imaging. RESULTS We show that a 54 h fasting period markedly decreases both cold-induced BAT glucose uptake and nonshivering thermogenesis (NST) during cold stimulation. In vivo molecular imaging and modelling revealed that the reduction of glucose uptake in BAT was due to impaired cellular glucose uptake and not due to decreased supply. Interestingly, decreased BAT glucose uptake upon fasting was related to a decrease in core temperature during cold exposure, pointing towards a role for BAT in maintaining normothermia in humans. CONCLUSIONS/INTERPRETATION Cold-stimulated glucose uptake in BAT is strongly reduced upon prolonged fasting. When cold-stimulated glucose uptake in BAT is also reduced under other insulin-resistant states, such as diabetes, cold-induced activation of BAT may not be a valid way to improve glucose clearance by BAT under such conditions. TRIAL REGISTRATION www.trialregister.nl NTR3523 FUNDING: This work was supported by the EU FP7 project DIABAT (HEALTH-F2-2011-278373 to WDvML) and by the Netherlands Organization for Scientific Research (TOP 91209037 to WDvML).
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Abstract
Obesity is the result of disequilibrium between energy intake and energy expenditure (EE). Successful long-term weight loss is difficult to achieve with current strategies for the correction of this caloric imbalance. Non-shivering thermogenesis (NST) in brown adipose tissue (BAT) is a possible therapeutic target for the prevention and treatment of obesity and associated metabolic diseases. In recent years, more knowledge about the function and stimulation of bat has been obtained. The sympathetic nervous system (SNS) is currently seen as the main effector for brown fat function. Also, interplay between the thyroid axis and SNS plays an important role in BAT thermogenesis. Almost daily new pathways for the induction of BAT thermogenesis and 'browning' of white adipose tissue (WAT) are identified. Especially the activation of BAT via endogenous pathways has received strong scientific attention. Here we will discuss the relevance of several pathways in activating BAT and their implications for the treatment of obesity. In this review we will focus on the discussion of the most promising endocrine and paracrine pathways to stimulate BAT, by factors and pathways that naturally occur in the human body.
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Horowitz M, Kenny GP, McAllen RM, van Marken Lichtenbelt WD. Thermal physiology in a changing thermal world. Temperature (Austin) 2015; 2:22-6. [PMID: 27226998 PMCID: PMC4843882 DOI: 10.1080/23328940.2015.1017088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 12/04/2022] Open
Abstract
This editorial focuses on articles submitted to the Temperature call "Thermal Physiology in a Changing Thermal World." It highlights an array of topics related to thermoregulatory and metabolic functions in adverse environments, and the complexity and adaptability of the systems to changing climatic conditions, at various levels of body organization.
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Abstract
Since 2009, the presence of brown adipose tissue (BAT) in adult humans has been irrefutably proven. It is estimated that active BAT can contribute up to 2.5-5% of resting metabolic rate in humans, suggesting that sustained activation of BAT may alleviate obesity and associated disorders. In the current chapter, the discovery of BAT in adult humans will be discussed. Furthermore, the characteristics of human BAT, methods to visualize the tissue as well as physiological and pharmacological methods to enhance its activity will be stressed.
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van der Lans AAJJ, Wierts R, Vosselman MJ, Schrauwen P, Brans B, van Marken Lichtenbelt WD. Cold-activated brown adipose tissue in human adults: methodological issues. Am J Physiol Regul Integr Comp Physiol 2014; 307:R103-13. [PMID: 24871967 DOI: 10.1152/ajpregu.00021.2014] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The relevance of functional brown adipose tissue (BAT) depots in human adults was undisputedly proven approximately seven years ago. Here we give an overview of all dedicated studies that were published on cold-induced BAT activity in adult humans that appeared since then. Different cooling protocols and imaging techniques to determine BAT activity are reviewed. BAT activation can be achieved by means of air- or water-cooling protocols. The most promising approach is individualized cooling, during which subjects are studied at the lowest temperature for nonshivering condition, probably revealing maximal nonshivering thermogenesis. The highest BAT prevalence (i.e., close to 100%) is observed using the individualized cooling protocol. Currently, the most widely used technique to study the metabolic activity of BAT is deoxy-2-[18F]fluoro-d-glucose ([18F]FDG)-positron emission tomography/computed tomography (PET/CT) imaging. Dynamic imaging provides quantitative information about glucose uptake rates, whereas static imaging reflects overall BAT glucose uptake, localization, and distribution. In general, standardized uptake values (SUV) are used to quantify BAT activity. An accurate determination of total BAT volume is hampered by the limited spatial resolution of the PET image, leading to spillover. Different research groups use different SUV threshold values, which make it difficult to directly compare BAT activity levels between studies. Another issue is the comparison of [18F]FDG uptake in BAT with respect to other tissues or upon with baseline values. This comparison can be performed by using the “fixed volume” methodology. Finally, the potential use of other relatively noninvasive methods to quantify BAT, like magnetic resonance imaging or thermography, is discussed.
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Vosselman MJ, Vijgen GHEJ, Kingma BRM, Brans B, van Marken Lichtenbelt WD. Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: a study in a monozygotic twin. PLoS One 2014; 9:e101653. [PMID: 25014028 PMCID: PMC4094425 DOI: 10.1371/journal.pone.0101653] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 06/06/2014] [Indexed: 02/02/2023] Open
Abstract
INTRODUCTION Mild cold acclimation is known to increase brown adipose tissue (BAT) activity and cold-induced thermogenesis (CIT) in humans. We here tested the effect of a lifestyle with frequent exposure to extreme cold on BAT and CIT in a Dutch man known as 'the Iceman', who has multiple world records in withstanding extreme cold challenges. Furthermore, his monozygotic twin brother who has a 'normal' sedentary lifestyle without extreme cold exposures was measured. METHODS The Iceman (subject A) and his brother (subject B) were studied during mild cold (13°C) and thermoneutral conditions (31°C). Measurements included BAT activity and respiratory muscle activity by [18F]FDG-PET/CT imaging and energy expenditure through indirect calorimetry. In addition, body temperatures, cardiovascular parameters, skin perfusion, and thermal sensation and comfort were measured. Finally, we determined polymorphisms for uncoupling protein-1 and β3-adrenergic receptor. RESULTS Subjects had comparable BAT activity (A: 1144 SUVtotal and B: 1325 SUVtotal), within the range previously observed in young adult men. They were genotyped with the polymorphism for uncoupling protein-1 (G/G). CIT was relatively high (A: 40.1% and B: 41.9%), but unlike during our previous cold exposure tests in young adult men, here both subjects practiced a g-Tummo like breathing technique, which involves vigorous respiratory muscle activity. This was confirmed by high [18F]FDG-uptake in respiratory muscle. CONCLUSION No significant differences were found between the two subjects, indicating that a lifestyle with frequent exposures to extreme cold does not seem to affect BAT activity and CIT. In both subjects, BAT was not higher compared to earlier observations, whereas CIT was very high, suggesting that g-Tummo like breathing during cold exposure may cause additional heat production by vigorous isometric respiratory muscle contraction. The results must be interpreted with caution given the low subject number and the fact that both participants practised the g-Tummo like breathing technique.
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Kingma BR, Frijns AJ, Schellen L, van Marken Lichtenbelt WD. Beyond the classic thermoneutral zone: Including thermal comfort. Temperature (Austin) 2014; 1:142-9. [PMID: 27583296 PMCID: PMC4977175 DOI: 10.4161/temp.29702] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 06/23/2014] [Accepted: 06/23/2014] [Indexed: 11/30/2022] Open
Abstract
The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached.
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Boon MR, Bakker LEH, van der Linden RAD, Pereira Arias-Bouda L, Smit F, Verberne HJ, van Marken Lichtenbelt WD, Jazet IM, Rensen PCN. Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects. PLoS One 2014; 9:e98822. [PMID: 24922545 PMCID: PMC4055666 DOI: 10.1371/journal.pone.0098822] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 05/07/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Brown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current 'gold standard' for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans. SUBJECTS/METHODS BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations. RESULTS Proximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not. CONCLUSIONS Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects. TRIAL REGISTRATION NTR 2473.
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Jacquot CM, Schellen L, Kingma BR, van Baak MA, van Marken Lichtenbelt WD. Influence of thermophysiology on thermal behavior: the essentials of categorization. Physiol Behav 2014; 128:180-7. [DOI: 10.1016/j.physbeh.2014.01.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/13/2013] [Accepted: 01/26/2014] [Indexed: 01/10/2023]
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Bakker LEH, Boon MR, van der Linden RAD, Arias-Bouda LP, van Klinken JB, Smit F, Verberne HJ, Jukema JW, Tamsma JT, Havekes LM, van Marken Lichtenbelt WD, Jazet IM, Rensen PCN. Brown adipose tissue volume in healthy lean south Asian adults compared with white Caucasians: a prospective, case-controlled observational study. Lancet Diabetes Endocrinol 2014; 2:210-7. [PMID: 24622751 DOI: 10.1016/s2213-8587(13)70156-6] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Individuals of south Asian origin have a very high risk of developing type 2 diabetes compared with white Caucasians. We aimed to assess volume and activity of brown adipose tissue (BAT), which is thought to have a role in energy metabolism by combusting fatty acids and glucose to produce heat and might contribute to the difference in incidence of type 2 diabetes between ethnic groups. METHODS We enrolled Dutch nationals with south Asian ancestry and matched Caucasian participants at The Rijnland Hospital (Leiderdorp, Netherlands). Eligible participants were healthy lean men aged 18-28 years, and we matched groups for BMI. We measured BAT volume and activity with cold-induced (18)F-fluorodeoxyglucose ((18)F-FDG) PET CT scans, and assessed resting energy expenditure, non-shivering thermogenesis, and serum parameters. This study is registered with the Netherlands Trial Register, number 2473. FINDINGS Between March 1, 2013, and June 1, 2013, we enrolled 12 participants in each group; one Caucasian participant developed hyperventilation after (18)F-FDG administration, and was excluded from all cold-induced and BAT measurements. Compared with Caucasian participants, south Asian participants did not differ in age (mean 23.6 years [SD 2.8] for south Asians vs 24.6 years [2.8] for Caucasians) or BMI (21.5 kg/m(2) [2.0] vs 22.0 kg/m(2) [1.6]), but were shorter (1.74 m [0.06] vs 1.85 m [0.04]) and lighter (65.0 kg [8.5] vs 75.1 kg [7.2]). Thermoneutral resting energy expenditure was 1297 kcal per day (SD 123) in south Asian participants compared with 1689 kcal per day (193) in white Caucasian participants (difference -32%, p=0.0008). On cold exposure, shiver temperature of south Asians was 2.0°C higher than Caucasians (p=0.0067) and non-shivering thermogenesis was increased by 20% in white Caucasians (p<0.0001) but was not increased in south Asians. Although the maximum and mean standardised uptake values of (18)F-FDG in BAT did not differ between groups, total BAT volume was lower in south Asians (188 mL [SD 81]) than it was in Caucasians (287 mL [169]; difference -34%, p=0.04). Overall, BAT volume correlated positively with basal resting energy expenditure in all assessable individuals (β=0.44, p=0.04). INTERPRETATION Lower resting energy expenditure, non-shivering thermogenesis, and BAT volumes in south Asian populations might underlie their high susceptibility to metabolic disturbances, such as obesity and type 2 diabetes. Development of strategies to increase BAT volume and activity might help prevent and treat such disorders, particularly in south Asian individuals. FUNDING Dutch Heart Foundation (2009T038) and Dutch Diabetes Research Foundation (2012.11.1500).
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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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