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Li X, Liang T, Dai B, Chang L, Zhang Y, Hu S, Guo J, Xu S, Zheng L, Yao H, Lian H, Nie Y, Li Y, He X, Yao Z, Tong W, Wang X, Chow DHK, Xu J, Qin L. Excess glucocorticoids inhibit murine bone turnover via modulating the immunometabolism of the skeletal microenvironment. J Clin Invest 2024; 134:e166795. [PMID: 38512413 DOI: 10.1172/jci166795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/15/2024] [Indexed: 03/23/2024] Open
Abstract
Elevated bone resorption and diminished bone formation have been recognized as the primary features of glucocorticoid-associated skeletal disorders. However, the direct effects of excess glucocorticoids on bone turnover remain unclear. Here, we explored the outcomes of exogenous glucocorticoid treatment on bone loss and delayed fracture healing in mice and found that reduced bone turnover was a dominant feature, resulting in a net loss of bone mass. The primary effect of glucocorticoids on osteogenic differentiation was not inhibitory; instead, they cooperated with macrophages to facilitate osteogenesis. Impaired local nutrient status - notably, obstructed fatty acid transportation - was a key factor contributing to glucocorticoid-induced impairment of bone turnover in vivo. Furthermore, fatty acid oxidation in macrophages fueled the ability of glucocorticoid-liganded receptors to enter the nucleus and then promoted the expression of BMP2, a key cytokine that facilitates osteogenesis. Metabolic reprogramming by localized fatty acid delivery partly rescued glucocorticoid-induced pathology by restoring a healthier immune-metabolic milieu. These data provide insights into the multifactorial metabolic mechanisms by which glucocorticoids generate skeletal disorders, thus suggesting possible therapeutic avenues.
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Affiliation(s)
- Xu Li
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Tongzhou Liang
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Bingyang Dai
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Liang Chang
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Yuan Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Shiwen Hu
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Jiaxin Guo
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Shunxiang Xu
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Lizhen Zheng
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Hao Yao
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Hong Lian
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant Materials, Animal Experimental Centre, and
| | - Yu Nie
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ye Li
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Xuan He
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Zhi Yao
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Wenxue Tong
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Xinluan Wang
- Centre for Translational Medicine Research and Development, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Dick Ho Kiu Chow
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Jiankun Xu
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
| | - Ling Qin
- Musculoskeletal Research Laboratory, Department of Orthopedics and Traumatology, Faculty of Medicine
- Innovative Orthopedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, and
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Obesity and dietary fat influence dopamine neurotransmission: exploring the convergence of metabolic state, physiological stress, and inflammation on dopaminergic control of food intake. Nutr Res Rev 2021; 35:236-251. [PMID: 34184629 DOI: 10.1017/s0954422421000196] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of this review is to explore how metabolic changes induced by diets high in saturated fat (HFD) affect nucleus accumbens (NAc) dopamine neurotransmission and food intake, and to explore how stress and inflammation influence this process. Recent evidence linked diet-induced obesity and HFD with reduced dopamine release and reuptake. Altered dopamine neurotransmission could disrupt satiety circuits between NAc dopamine terminals and projections to the hypothalamus. The NAc directs learning and motivated behaviours based on homeostatic needs and psychological states. Therefore, impaired dopaminergic responses to palatable food could contribute to weight gain by disrupting responses to food cues or stress, which impacts type and quantity of food consumed. Specifically, saturated fat promotes neuronal resistance to anorectic hormones and activation of immune cells that release proinflammatory cytokines. Insulin has been shown to regulate dopamine neurotransmission by enhancing satiety, but less is known about effects of diet-induced stress. Therefore, changes to dopamine signalling due to HFD warrant further examination to characterise crosstalk of cytokines with endocrine and neurotransmitter signals. A HFD promotes a proinflammatory environment that may disrupt neuronal endocrine function and dopamine signalling that could be exacerbated by the hypothalamic-pituitary-adrenal and κ-opioid receptor stress systems. Together, these adaptive changes may dysregulate eating by changing NAc dopamine during hedonic versus homeostatic food intake. This could drive palatable food cravings during energy restriction and hinder weight loss. Understanding links between HFD and dopamine neurotransmission will inform treatment strategies for diet-induced obesity and identify molecular candidates for targeted therapeutics.
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Nonsevere Diabetic Ketoacidosis and Adrenal Insufficiency: Exploring the Impact of Glucocorticoid Replacement on Metabolic Outcomes and ICU Length of Stay. Crit Care Explor 2020; 2:e0260. [PMID: 33196048 PMCID: PMC7655087 DOI: 10.1097/cce.0000000000000260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background: There is a paucity of clinical data on corticosteroid replacement in patients with adrenal insufficiency who present with nonsevere noncomplicated diabetic ketoacidosis. Case Summary: We analyzed five consecutive admissions for diabetic ketoacidosis of mild/moderate severity due to insulin omission in a 21-year-old man with type 1 diabetes and stable Addison disease. Despite similar presentations, the approach to steroid replacement differed: maintenance/moderate doses of hydrocortisone (< 60 mg/d) or high stress-doses (≥ 120 mg/d). Resolution of diabetic ketoacidosis and ICU and hospital length of stay were prolonged when high-dose versus maintenance/moderate glucocorticoids were provided: 45.5, 47.0, and 63.0 versus 12.0, 24.5, and 31 hours, respectively. Conclusions: Although our findings remain hypothesis-generating, our case study raises awareness on the importance of categorizing diabetic ketoacidosis by severity and complication status when deciding on the intensity of steroid replacement in patients with stable Addison disease. Excessive glucocorticoid administration may delay the resolution of nonsevere and otherwise noncomplicated diabetic ketoacidosis and prolong ICU and hospital stays.
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In-vivo metabolic studies of regional adipose tissue. Cardiovasc Endocrinol Metab 2019; 7:75-79. [PMID: 31646288 DOI: 10.1097/xce.0000000000000154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/20/2018] [Indexed: 11/26/2022]
Abstract
The accumulation of abdominal adipose tissue has long been associated with adverse cardiovascular outcomes. Paradoxically, increased gluteofemoral adipose tissue, which is predominantly subcutaneous fat, seems to play a protective role. There has been significant scientific interest in understanding how abdominal and gluteofemoral depots confer opposing metabolic risks. However, the study of regional adipose physiology in vivo remains challenging. We discuss some of the methodologies used. We focus specifically on the arteriovenous difference technique and present some insights into gluteofemoral adipose physiology.
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Ramshanker N, Jessen N, Voss TS, Pedersen SB, Jørgensen JOL, Nielsen TS, Frystyk J, Møller N. Effects of short-term prednisolone treatment on indices of lipolysis and lipase signaling in abdominal adipose tissue in healthy humans. Metabolism 2019; 99:1-10. [PMID: 31260678 DOI: 10.1016/j.metabol.2019.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/14/2019] [Accepted: 06/25/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND Glucocorticoid (GC) excess increases lipolysis, circulating free fatty acid concentrations and lipid oxidation rates in humans. In vitro and animal studies have shown that GCs increase adipocyte ATGL and HSL mRNA contents and HSL phosphorylations, but the effects of GC on in vivo lipase signaling in humans are uncertain. Our study was designed to test how GC administration affects ATGL and HSL related signals in human adipose tissue. MATERIAL AND METHODS Nine healthy young men underwent 5 days administration of 37.5 mg prednisolone/d in a randomized, double-blinded, placebo-controlled crossover design. At the end of each 5 d period the subjects were studied after an overnight fast for 6.5 h including a basal period and a 2½ h hyperinsulinemic euglycemic clamp. Adipose tissue biopsies were sampled from the abdominal subcutaneous adipose tissue at the end of the basal period and the clamp. RESULTS GC treatment increased serum FFA concentrations and comparative gene identification-58 (CGI-58) mRNA - an ATGL activator - and decreased G0/G1 switch 2 gene (G0S2) mRNA - an ATGL inhibitor - in adipose tissue biopsies. In addition, pro-lipolytic ser563 HSL phosphorylations and protein kinase A (PKA) phosphorylation of PLIN1 (Perilipin-1) increased. The transcripts of ANGPTL4 (Angiopoietin-like 4) mRNA - a regulator of circulating triglycerides - were elevated by GC; as were CIDE (Cell-death Inducing DNA fragmentation factor-α-like Effector)-A and CIDE-C mRNA transcripts indicative of concurrent stimulation of lipolysis and lipogenesis. Finally GCs reduced insulin receptor phosphorylation, and Akt protein levels. CONCLUSIONS High dose GC administration to humans leads to pro-lipolytic alterations of CGI-58, G0S2 and ANGPTL4 mRNA transcripts, increases PKA signaling to lipolysis and inhibits the insulin signal in adipose tissue. The increased CIDE-A and CIDE-C mRNA levels suggest concomitant stimulation of lipolysis and lipid storage.
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Affiliation(s)
- Nilani Ramshanker
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark.
| | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 99, DK-8200 Aarhus N, Denmark; Department of Clinical Pharmacology, Wilhelm Meyers Allé 4, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Thomas Schmidt Voss
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark
| | - Steen Bønløkke Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
| | - Jens Otto Lunde Jørgensen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
| | - Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3A, DK-2200 Copenhagen N, Denmark
| | - Jan Frystyk
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
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Pranger IG, van Raalte DH, Brands M, Muskiet MHA, Kema IP, Serlie MJ, Diamant M, Bakker SJL, Muskiet FAJ. Influence of prednisolone on parameters of de novo lipogenesis and indices for stearoyl-CoA- and Δ6- desaturase activity in healthy males: A Post-hoc analysis of a randomized, placebo-controlled, double-blind trial. Prostaglandins Leukot Essent Fatty Acids 2018; 132:8-15. [PMID: 29735021 DOI: 10.1016/j.plefa.2018.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/26/2018] [Accepted: 03/29/2018] [Indexed: 01/28/2023]
Abstract
Glucocorticoid treatment decreases liver insulin sensitivity and may modify fatty acid metabolism. We investigated the influence of oral prednisolone on indices for de novo lipogenesis (DNLi), stearoyl-CoA desaturase (SCDi) and Δ6-desaturase (D6Di) activity in healthy males. In addition, we explored whether the changes may be associated with prednisolone-induced changes in glucose and lipid metabolism and insulin sensitivity. Thirty-two healthy young males (mean ± SD age 22 ± 3 years, BMI 22.4 ± 1.7 kg/m2) were allocated to receive prednisolone 7.5 mg/day (PRED7.5; n = 12), prednisolone 30 mg/day (PRED30; n = 12), or placebo (n = 8) in a randomized double-blind fashion for 2 weeks. Fatty acid compositions of plasma cholesteryl esters (CE), phospholipids (PL) and triglycerides (TG) were measured at baseline and on day 14. DNLi, SCDi and D6Di were estimated from product/precursor ratios in CE, with DNLi primary deriving from 16:1ω7/18:2ω6, SCDi from 16:1ω7/16:0 and D6Di from 22:6ω3/20:5ω3. Ratios were also assessed in PL and TG. In CE, PRED30 increased DNLi by 51.2 [95%CI 14.8; 87.6]%, increased SCDi by 48.6 [18.7; 78.5]%, and decreased D6Di by 57.7 [-91.8; -23.5]% (p ≤ 0.01 for all, compared to placebo). The prednisolone-induced increases in DNLi and SCDi were positively correlated with insulin sensitivity (r = 0.35 and 0.50, respectively). Similar results were found in PL and TG. Prednisolone dose-dependently increases DNLi and SCDi and decreases D6Di in plasma CE, PL and TG in healthy males after 2 weeks. The observed unfavorable effects on fatty acid metabolism were related to the induction of glucocorticoid-induced insulin resistance.
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Affiliation(s)
- I G Pranger
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - D H van Raalte
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - M Brands
- Department of Endocrinology and Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - M H A Muskiet
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - I P Kema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - M Diamant
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - S J L Bakker
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - F A J Muskiet
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Manolopoulos KN, O'Reilly MW, Bujalska IJ, Tomlinson JW, Arlt W. Acute Hypercortisolemia Exerts Depot-Specific Effects on Abdominal and Femoral Adipose Tissue Function. J Clin Endocrinol Metab 2017; 102:1091-1101. [PMID: 28323916 PMCID: PMC5460725 DOI: 10.1210/jc.2016-3600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/13/2017] [Indexed: 01/20/2023]
Abstract
CONTEXT Glucocorticoids have pleiotropic metabolic functions, and acute glucocorticoid excess affects fatty acid metabolism, increasing systemic lipolysis. Whether glucocorticoids exert adipose tissue depot-specific effects remains unclear. OBJECTIVE To provide an in vivo assessment of femoral and abdominal adipose tissue responses to acute glucocorticoid administration. DESIGN AND OUTCOME MEASURES Nine healthy male volunteers were studied on two occasions, after a hydrocortisone infusion (0.2 mg/kg/min for 14 hours) and a saline infusion, respectively, given in randomized double-blind order. The subjects were studied in the fasting state and after a 75-g glucose drink with an in vivo assessment of femoral adipose tissue blood flow (ATBF) using radioactive xenon washout and of lipolysis and glucose uptake using the arteriovenous difference technique. In a separate study (same infusion design), eight additional healthy male subjects underwent assessment of fasting abdominal ATBF and lipolysis only. Lipolysis was assessed as the net release of nonesterified fatty acids (NEFAs) from femoral and abdominal subcutaneous adipose tissue. RESULTS Acute hypercortisolemia significantly increased basal and postprandial ATBF in femoral adipose tissue, but the femoral net NEFA release did not change. In abdominal adipose tissue, hypercortisolemia induced substantial increases in basal ATBF and NEFA release. CONCLUSIONS Acute hypercortisolemia induces differential lipolysis and ATBF responses in abdominal and femoral adipose tissue, suggesting depot-specific glucocorticoid effects. Abdominal, but not femoral, adipose tissue contributes to the hypercortisolemia-induced systemic NEFA increase, with likely contributions from other adipose tissue sources and intravascular triglyceride hydrolysis.
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Affiliation(s)
- Konstantinos N Manolopoulos
- Institute of Metabolism and Systems Research, University of Birmingham B15 2TT, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, United Kingdom
| | - Michael W O'Reilly
- Institute of Metabolism and Systems Research, University of Birmingham B15 2TT, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, United Kingdom
| | - Iwona J Bujalska
- Institute of Metabolism and Systems Research, University of Birmingham B15 2TT, United Kingdom
| | - Jeremy W Tomlinson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham B15 2TT, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, United Kingdom
- National Institute for Health Research Birmingham Liver Biomedical Research Unit, University Hospitals Birmingham, National Health Service Foundation Trust, Birmingham B15 2TH, United Kingdom
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Delarue J, Allain-Jeannic G, Guillerm S, Cruciani-Guglielmacci C, Magnan C, Moineau MP, Le Guen V. Interaction of low dose of fish oil and glucocorticoids on insulin sensitivity and lipolysis in healthy humans: A randomized controlled study. Mol Nutr Food Res 2016; 60:886-96. [PMID: 26821227 DOI: 10.1002/mnfr.201500469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 11/08/2015] [Accepted: 12/29/2015] [Indexed: 11/06/2022]
Abstract
SCOPE This study examined the interaction of fish oil (FO) with dexamethasone on glucose and lipid metabolisms in healthy subjects. METHODS AND RESULTS The study included two consecutive parts. Part A (randomized) in 16 subjects studied the effects of dexamethasone (2 days, 2 mg/day) versus placebo (lactose), part B (two parallel subgroups of eight) studied the interaction of FO (3 wk, 840 mg/day of EPA + DHA) with dexamethasone. Insulin sensitivity of lipolysis (d5-glycerol infusion + microdialysis), endogenous glucose production, and muscle glucose uptake were assessed by a three-step hot insulin clamp and substrate oxidation by indirect calorimetry. Dexamethasone induced liver and peripheral insulin resistance, an increase in fat oxidation, and a decrease in suppression of plasma nonesterified fatty acids (NEFAs). FO amplified the effects of dexamethasone by increasing liver and muscle insulin resistance, by reducing suppression of plasma NEFAs and fat oxidation and by increasing adipose tissue (AT) lipolysis. CONCLUSION FO, given at a moderate dose in healthy subjects prior to a very short-term (2 days) low dose of a synthetic glucocorticoid, worsened its deleterious effects on insulin sensitivity. The enhancing effect of FO on fat oxidation and AT lipolysis might be a protective effect toward an increase in fat mass.
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Affiliation(s)
- Jacques Delarue
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France.,Breton Federation of Food and Human Nutrition (FED4216), University of Brest, Brest, France
| | - Gwenola Allain-Jeannic
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
| | - Sophie Guillerm
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
| | | | - Christophe Magnan
- BFA, UMR 8251 CNRS, Sorbonne Paris Cité, University Paris Diderot, Paris, France
| | - Marie-Pierre Moineau
- Department of Biochemistry and Pharmacology Toxicology, University Hospital of Brest, Brest University, Brest, France
| | - Valérie Le Guen
- Department of Nutritional Sciences & Laboratory of Human Nutrition, University Hospital of Brest, Brest University, Brest, France
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Albayrak S, Atci İB, Kalayci M, Yilmaz M, Kuloglu T, Aydin S, Kom M, Ayden O, Aydin S. Effect of carnosine, methylprednisolone and their combined application on irisin levels in the plasma and brain of rats with acute spinal cord injury. Neuropeptides 2015; 52:47-54. [PMID: 26142757 DOI: 10.1016/j.npep.2015.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/09/2015] [Accepted: 06/11/2015] [Indexed: 01/02/2023]
Abstract
Spinal cord injury (SCI) might occur to anybody at any time and any age. In its treatment, methylprednisolone (MP) is a first choice worldwide, but there is still no significant breakthrough in truly beneficial treatment due to SCI's complex pathophysiology. We investigated the effect of carnosine, methylprednisolone (MP) and its combination on irisin levels in the plasma, brain and medulla spinalis tissues in SCI using a rat model. The rats were divided into 6 groups: I (Control, saline); II (sham animals with laminectomy without cross-clamping); III (SCI); IV (SCI treated with 150mg/kg carnosine); V (SCI treated with 30mg/kg methylprednisolone); and VI (SCI treated with a combination of carnosine and MP). The animals were given traumatic SCI after laminectomy, using 70-g closing force aneurysm clips (Yasargil FE 721). Irisin concentration was measured by ELISA. The distribution of irisin in brain and spinal cord tissues was examined by immunochemistry. Irisin was mainly expressed in the astrocytes and microglia of brain tissues, and multipolar neurones of the anterior horn of spinal cord tissue in rats of all groups, indicating that irisin is physiologically indispensable. MP and carnosine and the combination of the two, significantly increased irisin in plasma and were accompanied by a significant rise in irisin immunoreactivity of brain and spinal cord tissues of the injured rats compared with control and sham. This finding raises the possibility that methylprednisolone and carnosine regulate the brain and spinal cord tissues in SCI by inducing irisin expression, and may therefore offer a better neurological prognosis.
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Affiliation(s)
- Serdal Albayrak
- Department of Neurosurgery, Elazig Education and Research Hospital, 23100, Elazig, Turkey
| | - İbrahim Burak Atci
- Department of Neurosurgery, Elazig Education and Research Hospital, 23100, Elazig, Turkey
| | - Mehmet Kalayci
- Laboratory of Medical Biochemistry, Elazig Education and Research Hospital, Elazig 23100, Turkey
| | - Musa Yilmaz
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey
| | - Tuncay Kuloglu
- Firat University, School of Medicine, Department of Histology&Embryology, 23119, Elazig, Turkey
| | - Suna Aydin
- Cardiovascular Surgery- Anatomy, Elazig Education and Research Hospital, 23100, Elazig, Turkey
| | - Mustafa Kom
- Firat University, Veterinary of Medicine, Department of Surgery, Elazig 23119, Turkey
| | - Omer Ayden
- Department of Neurosurgery, Elazig Education and Research Hospital, 23100, Elazig, Turkey
| | - Suleyman Aydin
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey.
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Abstract
The distribution of adipose tissue in the body has wide-ranging and reproducible associations with health and disease. Accumulation of adipose tissue in the upper body (abdominal obesity) is associated with the development of cardiovascular disease, insulin resistance, type 2 diabetes mellitus and even all-cause mortality. Conversely, accumulation of fat in the lower body (gluteofemoral obesity) shows opposite associations with cardiovascular disease and type 2 diabetes mellitus when adjusted for overall fat mass. The abdominal depots are characterized by rapid uptake of predominantly diet-derived fat and a high lipid turnover that is easily stimulated by adrenergic receptor activation. The lower-body fat stores have a reduced lipid turnover with a capacity to accommodate fat undergoing redistribution. Lower-body adipose tissue also seems to retain the capacity to recruit additional adipocytes as a result of weight gain and demonstrates fewer signs of inflammatory insult. New data suggest that the profound functional differences between the upper-body and lower-body tissues are controlled by site-specific sets of developmental genes, such as HOXA6, HOXA5, HOXA3, IRX2 and TBX5 in subcutaneous abdominal adipose tissue and HOTAIR, SHOX2 and HOXC11 in gluteofemoral adipose tissue, which are under epigenetic control. This Review discusses the developmental and functional differences between upper-body and lower-body fat depots and provides mechanistic insight into the disease-protective effects of lower-body fat.
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Affiliation(s)
- Fredrik Karpe
- 1] Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Headington OX3 7LE, UK. [2] NIHR Oxford Biomedical Research Centre, OUH Trust, Churchill Hospital, Headington OX3 7LE, UK
| | - Katherine E Pinnick
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Headington OX3 7LE, UK
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Abstract
Glucocorticoids (GCs) and their cognate, intracellular receptor, the glucocorticoid receptor (GR) have been characterized as critical checkpoints in the hormonal control of energy homeostasis in mammals. Whereas physiological levels of GCs are required for proper metabolic control, aberrant GC action has been linked to a variety of severe metabolic diseases, including type 2 diabetes and obesity. As a member of the nuclear receptor superfamily of transcription factors, the GR translocates into the cell nucleus upon GC binding where it serves as a transcriptional regulator of distinct GC-responsive target genes that are in many cases associated with lipid regulatory pathways and thereby intricately control both physiological and pathophysiological systemic lipid homeostasis. Thus, this chapter focuses on the current knowledge of GC/GR function in lipid handling and its implications for systemic metabolic dysfunction.
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Calbet JAL, Ponce-González JG, Pérez-Suárez I, de la Calle Herrero J, Holmberg HC. A time-efficient reduction of fat mass in 4 days with exercise and caloric restriction. Scand J Med Sci Sports 2014; 25:223-33. [PMID: 24602091 DOI: 10.1111/sms.12194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2014] [Indexed: 12/29/2022]
Abstract
To determine whether a fast reduction in fat mass can be achieved in 4 days by combining caloric restriction (CR: 3.2 kcal/kg body weight per day) with exercise (8-h walking + 45-min arm cranking per day) to induce an energy deficit of ∼5000 kcal/day, 15 overweight men underwent five experimental phases: pretest, exercise + CR for 4 days (WCR), control diet + reduced exercise for 3 days (DIET), and follow-up 4 weeks (POST1) and 1 year later (POST2). During WCR, the diet consisted solely of whey protein (n = 8) or sucrose (n = 7) (0.8 g/kg body weight per day). After WCR, DIET, POST1, and POST2, fat mass was reduced by a mean of 2.1, 2.8, 3.8, and 1.9 kg (P < 0.05), with two thirds of this loss from the trunk; and lean mass by 2.8, 1.0, 0.5, and 0.4 kg, respectively. After WCR, serum glucose, insulin, homeostatic model assessment, total and low-density lipoprotein cholesterol and triglycerides were reduced, and free fatty acid and cortisol increased. Serum leptin was reduced by 64%, 50%, and 33% following WCR, DIET, and POST1, respectively (P < 0.05). The effects were similar in both groups. In conclusion, a clinically relevant reduction in fat mass can be achieved in overweight men in just 4 days by combining prolonged exercise with CR.
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Affiliation(s)
- J A L Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands, Spain; Instituto Universitario de Investigaciones Biomédicas y Sanitarias de la Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands, Spain
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13
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Akiyama N, Akiyama Y, Kato H, Kuroda T, Ono T, Imagawa K, Asakura K, Shinosaki T, Murayama T, Hanasaki K. Pharmacological evaluation of adipose dysfunction via 11β-hydroxysteroid dehydrogenase type 1 in the development of diabetes in diet-induced obese mice with cortisone pellet implantation. J Pharmacol Exp Ther 2014; 349:66-74. [PMID: 24511146 DOI: 10.1124/jpet.113.210716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Signals from intracellular glucocorticoids (GCs) via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in adipose tissues have been reported to serve as amplifiers leading to deterioration of glucose metabolism associated with obesity. To elucidate adipose dysfunction via 11β-HSD1 activation in the development of obesity-related diabetes, we established novel diabetic mice by implanting a cortisone pellet (CP) in diet-induced obesity (DIO) mice. Cortisone pellet-implanted DIO mice (DIO/CP mice) showed hyperglycemia, insulin resistance, hyperlipidemia, and ectopic fat accumulation, whereas cortisone pellet implantation in lean mice did not induce hyperglycemia. In DIO/CP mice, indexes of lipolysis such as plasma glycerol and nonesterified fatty acids (NEFAs) increased before hyperglycemia appeared. Furthermore, the adipose mRNA level of 11β-HSD1 was up-regulated in DIO/CP mice compared with sham-operated DIO mice. RU486 (mifepristone, 11β-[p-(dimethylamino)phenyl]-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one), a glucocorticoid receptor antagonist, decreased adipose mRNA levels of 11β-HSD1 as well as adipose triglyceride lipase. RU486 also improved plasma NEFA, glycerol, and glucose levels in DIO/CP mice. These results demonstrate that lipolysis in adipose tissues caused by GC activation via 11β-HSD1 serves as a trigger for diabetes with ectopic fat accumulation. Our findings also indicate the possibility of a vicious circle of GC signals via 11β-HSD1 up-regulation in adipose tissues, contributing to deterioration of glucose metabolism to result in diabetes. Our DIO/CP mouse could be a suitable model of type 2 diabetes to evaluate adipose dysfunction via 11β-HSD1.
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Affiliation(s)
- Nobuteru Akiyama
- Medicinal Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan (N.A., Y.A., H.K., T.K., T.O., K.I., K.A., T.S., K.H.); and Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan (N.A., T.M.)
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Rose AJ, Herzig S. Metabolic control through glucocorticoid hormones: an update. Mol Cell Endocrinol 2013; 380:65-78. [PMID: 23523966 DOI: 10.1016/j.mce.2013.03.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 02/21/2013] [Accepted: 03/08/2013] [Indexed: 01/28/2023]
Abstract
In the past decades, glucocorticoid (GC) hormones and their cognate, intracellular receptor, the glucocorticoid receptor (GR), have been well established as critical checkpoints in mammalian energy homeostasis. Whereas many aspects in healthy nutrient metabolism require physiological levels and/or action of GC, aberrant GC/GR signalling has been linked to severe metabolic dysfunction, including obesity, insulin resistance and type 2 diabetes. Consequently, studies of the molecular mechanisms within the GC signalling axis have become a major focus in biomedical research, up-to-date particularly focusing on systemic glucose and lipid handling. However, with the availability of novel high throughput technologies and more sophisticated metabolic phenotyping capabilities, as-yet non-appreciated, metabolic functions of GC have been recently discovered, including regulatory roles of the GC/GR axis in protein and bile acid homeostasis as well as metabolic inter-organ communication. Therefore, this review summarises recent advances in GC/GR biology, and summarises findings relevant for basic and translational metabolic research.
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Affiliation(s)
- Adam J Rose
- Joint Research Division, Molecular Metabolic Control, German Cancer Research Center (DKFZ) Heidelberg, Center for Molecular Biology (ZMBH), Heidelberg University, Network Aging Research, University Hospital Heidelberg, Germany
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Metabolic Signatures of Kidney Yang Deficiency Syndrome and Protective Effects of Two Herbal Extracts in Rats Using GC/TOF MS. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:540957. [PMID: 24159348 PMCID: PMC3789486 DOI: 10.1155/2013/540957] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/04/2013] [Accepted: 08/06/2013] [Indexed: 11/25/2022]
Abstract
Kidney Yang Deficiency Syndrome (KDS-Yang), a typical condition in Chinese medicine, shares similar clinical signs of the glucocorticoid withdrawal syndrome. To date, the underlying mechanism of KDS-Yang has been remained unclear, especially at the metabolic level. In this study, we report a metabolomic profiling study on a classical model of KDS-Yang in rats induced by hydrocortisone injection to characterize the metabolic transformation using gas chromatography/time-of-flight mass spectrometry. WKY1, a polysaccharide extract from Astragalus membranaceus and Lycium barbarum, and WKY2, an aqueous extract from a similar formula containing Astragalus membranaceus, Lycium barbarum, Morinda officinalis, Taraxacum mongolicum, and Cinnamomum cassia presl, were used separately for protective treatments of KDS-Yang. The changes of serum metabolic profiles indicated that significant alterations of key metabolic pathways in response to abrupt hydrocortisone perturbation, including decreased energy metabolism (lactic acid, acetylcarnitine), lipid metabolism (free fatty acids, 1-monolinoleoylglycerol, and cholesterol), gut microbiota metabolism (indole-3-propionic acid), biosynthesis of catecholamine (norepinephrine), and elevated alanine metabolism, were attenuated or normalized with different degrees by the pretreatment of WKY1 or WKY2, which is consistent with the observations in which the two herbal agents could ameliorate biochemical markers of serum cortisone, adrenocorticotropic (ACTH), and urine 17-hydroxycorticosteroids (17-OHCS).
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Abstract
Background Glucocorticoids, such as prednisolone, are widely used anti-inflammatory drugs, but therapy is hampered by a broad range of metabolic side effects including skeletal muscle wasting and insulin resistance. Therefore, development of improved synthetic glucocorticoids that display similar efficacy as prednisolone but reduced side effects is an active research area. For efficient development of such new drugs, in vivo biomarkers, which can predict glucocorticoid metabolic side effects in an early stage, are needed. In this study, we aim to provide the first description of the metabolic perturbations induced by acute and therapeutic treatments with prednisolone in humans using urine metabolomics, and to derive potential biomarkers for prednisolone-induced metabolic effects. Methods A randomized, double blind, placebo-controlled trial consisting of two protocols was conducted in healthy men. In protocol 1, volunteers received placebo (n = 11) or prednisolone (7.5 mg (n = 11), 15 mg (n = 13) or 30 mg (n = 12)) orally once daily for 15 days. In protocol 2, volunteers (n = 6) received placebo at day 0 and 75 mg prednisolone at day 1. We collected 24 h urine and serum samples at baseline (day 0), after a single dose (day 1) and after prolonged treatment (day 15) and obtained mass-spectrometry-based urine and serum metabolic profiles. Results At day 1, high-dose prednisolone treatment increased levels of 13 and 10 proteinogenic amino acids in urine and serum respectively, as well as levels of 3-methylhistidine, providing evidence for an early manifestation of glucocorticoid-induced muscle wasting. Prednisolone treatment also strongly increased urinary carnitine derivatives at day 1 but not at day 15, which might reflect adaptive mechanisms under prolonged treatment. Finally, urinary levels of proteinogenic amino acids at day 1 and of N-methylnicotinamide at day 15 significantly correlated with the homeostatic model assessment of insulin resistance and might represent biomarkers for prednisolone-induced insulin resistance. Conclusion This study provides evidence that urinary metabolomics represents a noninvasive way of monitoring the effect of glucocorticoids on muscle protein catabolism after a single dose and can derive new biomarkers of glucocorticoid-induced insulin resistance. It might, therefore, help the development of improved synthetic glucocorticoids. Trial Registration ClinicalTrials.gov NCT00971724
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Banasik JL, Walker MK, Randall JM, Netjes RB, Foutz MS. Low-calorie diet induced weight loss may alter regulatory hormones and contribute to rebound visceral adiposity in obese persons with a family history of type-2 diabetes. J Am Assoc Nurse Pract 2012; 25:440-448. [PMID: 24170641 DOI: 10.1111/j.1745-7599.2012.00808.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE To examine potential detrimental long-term effects of acute diet-induced weight loss on visceral adiposity, insulin resistance, cortisol, and adipokines in obese individuals at risk for type-2 diabetes. DATA SOURCES Anthropometric measures (height, weight, waist circumference), self-report instruments, abdominal computed tomography (CT) scan, and blood samples (glucose, insulin, interleukin-6, leptin, adiponectin) were obtained from a convenience sample of 20 participants at baseline, after a 28-day low-calorie diet (800 kcal/day) intervention, and again 6 months later. CONCLUSIONS Fifteen of 20 participants completed the 28-day diet intervention and had a mean weight loss of 15 pounds. Comparison between baseline, postdiet, and 6-month data, demonstrated that although participants had significant improvements after the diet, they regained fat mass, particularly in the visceral area. IMPLICATIONS FOR PRACTICE Clinicians may need to revise recommendations for using low-calorie diets to achieve weight loss. Diet-induced weight cycling may contribute to dysregulation of metabolism and have long-term detrimental consequences for accumulation of visceral adipose tissue. The likelihood of success is low, with high dropout rates, and those patients who achieve weight loss are very likely to regain it. Thus, the perceived short-term benefits of calorie-restricted diets in this population likely do not outweigh the potential long-term detrimental effects.
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Affiliation(s)
- Jacquelyn L Banasik
- (Associate Professor), (Family Nurse Practitioner), College of Nursing, Washington State University, Spokane, Washington (Family Nurse Practitioner), Inland Imaging, Spokane, Washington (Family Nurse Practitioner), Veteran's Administration, Spokane, Washington (Family Nurse Practitioner), Cancer Care Northwest, Spokane, Washington
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Wang X, Magkos F, Patterson BW, Reeds DN, Kampelman J, Mittendorfer B. Low-dose dexamethasone administration for 3 weeks favorably affects plasma HDL concentration and composition but does not affect very low-density lipoprotein kinetics. Eur J Endocrinol 2012; 167:217-23. [PMID: 22619349 PMCID: PMC3638974 DOI: 10.1530/eje-12-0180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Subclinical hypercortisolemia often occurs in subjects with features of the metabolic syndrome, and it has been suggested that it may be, at least in part, responsible for the development of these metabolic abnormalities. However, the metabolic effects of glucocorticoid administration to mimic subclinical glucocorticoid excess have not been evaluated. METHODS We used stable isotope-labeled tracer methods in conjunction with magnetic resonance techniques to measure the effect of glucocorticoid excess within the physiological range (~0.7 mg dexamethasone/day for 3 weeks) on glucose and free fatty acid (FFA) rates of appearance (Ra) into plasma, intrahepatic triglyceride (TG) content, very low-density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 (apoB-100) kinetics and plasma lipoprotein subclass concentrations, and particle sizes in nine overweight and obese individuals. RESULTS Dexamethasone treatment led to a very small but significant increase in body weight (from 87.4±7.1 to 88.6±7.2 kg; P=0.003) and increased HDL-cholesterol (from 45.9±2.8 to 55.1±4.6 mg/dl; P=0.037) and HDL particle (from 33.7±2.2 to 41.4±4.2 nmol/l; P=0.023) concentrations in plasma but had no effect on intrahepatic TG content, glucose and FFA Ra in plasma, hepatic VLDL-TG and VLDL-apoB-100 secretion rates and mean residence times in the circulation, plasma TG and LDL-cholesterol concentrations, and plasma lipoprotein particle sizes. CONCLUSION Subclinical hypercortisolemia does not have significant adverse metabolic consequences.
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Affiliation(s)
- Xuewen Wang
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, Center for Human Nutrition, St Louis, Missouri 63110, USA
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Gray NE, Lam LN, Yang K, Zhou AY, Koliwad S, Wang JC. Angiopoietin-like 4 (Angptl4) protein is a physiological mediator of intracellular lipolysis in murine adipocytes. J Biol Chem 2012; 287:8444-56. [PMID: 22267746 DOI: 10.1074/jbc.m111.294124] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intracellular triacylglycerol (TG) hydrolysis and fatty acid release by the white adipose tissue (WAT) during a fast is stimulated by counter-regulatory factors acting in concert, although how adipocytes integrate these lipolytic inputs is unknown. We tested the role of angiopoietin-like 4 (Angptl4), a secreted protein induced by fasting or glucocorticoid treatment, in modulating intracellular adipocyte lipolysis. Glucocorticoid receptor blockade prevented fasting-induced tissue Angptl4 expression and WAT TG hydrolysis in mice, and TG hydrolysis induced by fasts of 6 or 24 h was greatly reduced in mice lacking Angptl4 (Angptl4(-/-)). Glucocorticoid treatment mimicked the lipolytic effects of fasting, although with slower kinetics, and this too required Angptl4. Thus, fasting-induced WAT TG hydrolysis requires glucocorticoid action and Angptl4. Both fasting and glucocorticoid treatment also increased WAT cAMP levels and downstream phosphorylation of lipolytic enzymes. Angptl4 deficiency markedly reduced these effects, suggesting that Angptl4 may stimulate lipolysis by modulating cAMP-dependent signaling. In support of this, cAMP levels and TG hydrolysis were reduced in primary Angptl4(-/-) murine adipocytes treated with catecholamines, which stimulate cAMP-dependent signaling to promote lipolysis, and was restored by treatment with purified human ANGPTL4. Remarkably, human ANGPTL4 treatment alone increased cAMP levels and induced lipolysis in these cells. Pharmacologic agents revealed that Angptl4 modulation of cAMP-dependent signaling occurs upstream of adenylate cyclase and downstream of receptor activation. We show that Angptl4 is a glucocorticoid-responsive mediator of fasting-induced intracellular lipolysis and stimulates cAMP signaling in adipocytes. Such a role is relevant to diseases of aberrant lipolysis, such as insulin resistance.
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Affiliation(s)
- Nora E Gray
- Department of Nutritional Science and Toxicology, University of California, Berkeley, California 94720-3104, USA
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20
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van Raalte DH, Brands M, van der Zijl NJ, Muskiet MH, Pouwels PJW, Ackermans MT, Sauerwein HP, Serlie MJ, Diamant M. Low-dose glucocorticoid treatment affects multiple aspects of intermediary metabolism in healthy humans: a randomised controlled trial. Diabetologia 2011; 54:2103-12. [PMID: 21562755 PMCID: PMC3131514 DOI: 10.1007/s00125-011-2174-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/31/2011] [Indexed: 12/26/2022]
Abstract
AIM/HYPOTHESIS To assess whether low-dose glucocorticoid treatment induces adverse metabolic effects, as is evident for high glucocorticoid doses. METHODS In a randomised placebo-controlled double-blind (participants and the investigators who performed the studies and assessed the outcomes were blinded) dose-response intervention study, 32 healthy men (age 22 ± 3 years; BMI 22.4 ± 1.7 kg/m(2)) were allocated to prednisolone 7.5 mg once daily (n = 12), prednisolone 30 mg once daily (n = 12), or placebo (n = 8) for 2 weeks using block randomisation. Main outcome measures were glucose, lipid and protein metabolism, measured by stable isotopes, before and at 2 weeks of treatment, in the fasted state and during a two-step hyperinsulinaemic clamp conducted in the Clinical Research Unit of the Academic Medical Centre, Amsterdam, the Netherlands RESULTS Prednisolone, compared with placebo, dose dependently and significantly increased fasting plasma glucose levels, whereas only prednisolone 30 mg increased fasting insulin levels (29 ± 15 pmol/l). Prednisolone 7.5 mg and prednisolone 30 mg decreased the ability of insulin to suppress endogenous glucose production (by 17 ± 6% and 46 ± 7%, respectively, vs placebo). Peripheral glucose uptake was not reduced by prednisolone 7.5 mg, but was decreased by prednisolone 30 mg by 34 ± 6% (p < 0.0001). Compared with placebo, prednisolone treatment tended to decrease lipolysis in the fasted state (p = 0.062), but both prednisolone 7.5 mg and prednisolone 30 mg decreased insulin-mediated suppression of lipolysis by 11 ± 5% and 34 ± 6%, respectively. Finally, prednisolone treatment increased whole-body proteolysis during hyperinsulinaemia, which tended to be driven by prednisolone 30 mg (5 ± 2%; p = 0.06). No side effects were reported by the study participants. All participants completed the study and were analysed. CONCLUSIONS/INTERPRETATION Not only at high doses but also at low doses, glucocorticoid therapy impaired intermediary metabolism by interfering with the metabolic actions of insulin on liver and adipose tissue. These data indicate that even low-dose glucocorticoids may impair glucose tolerance when administered chronically. TRIAL REGISTRATION ISRCTN83991850.
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Affiliation(s)
- D H van Raalte
- Diabetes Centre, Department of Internal Medicine, VU University Medical Centre, de Boelelaan 1117, 1007 MB, Amsterdam, the Netherlands.
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Yu CY, Mayba O, Lee JV, Tran J, Harris C, Speed TP, Wang JC. Genome-wide analysis of glucocorticoid receptor binding regions in adipocytes reveal gene network involved in triglyceride homeostasis. PLoS One 2010; 5:e15188. [PMID: 21187916 PMCID: PMC3004788 DOI: 10.1371/journal.pone.0015188] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 10/28/2010] [Indexed: 01/19/2023] Open
Abstract
Glucocorticoids play important roles in the regulation of distinct aspects of adipocyte biology. Excess glucocorticoids in adipocytes are associated with metabolic disorders, including central obesity, insulin resistance and dyslipidemia. To understand the mechanisms underlying the glucocorticoid action in adipocytes, we used chromatin immunoprecipitation sequencing to isolate genome-wide glucocorticoid receptor (GR) binding regions (GBRs) in 3T3-L1 adipocytes. Furthermore, gene expression analyses were used to identify genes that were regulated by glucocorticoids. Overall, 274 glucocorticoid-regulated genes contain or locate nearby GBR. We found that many GBRs were located in or nearby genes involved in triglyceride (TG) synthesis (Scd-1, 2, 3, GPAT3, GPAT4, Agpat2, Lpin1), lipolysis (Lipe, Mgll), lipid transport (Cd36, Lrp-1, Vldlr, Slc27a2) and storage (S3-12). Gene expression analysis showed that except for Scd-3, the other 13 genes were induced in mouse inguinal fat upon 4-day glucocorticoid treatment. Reporter gene assays showed that except Agpat2, the other 12 glucocorticoid-regulated genes contain at least one GBR that can mediate hormone response. In agreement with the fact that glucocorticoids activated genes in both TG biosynthetic and lipolytic pathways, we confirmed that 4-day glucocorticoid treatment increased TG synthesis and lipolysis concomitantly in inguinal fat. Notably, we found that 9 of these 12 genes were induced in transgenic mice that have constant elevated plasma glucocorticoid levels. These results suggested that a similar mechanism was used to regulate TG homeostasis during chronic glucocorticoid treatment. In summary, our studies have identified molecular components in a glucocorticoid-controlled gene network involved in the regulation of TG homeostasis in adipocytes. Understanding the regulation of this gene network should provide important insight for future therapeutic developments for metabolic diseases.
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Affiliation(s)
- Chi-Yi Yu
- Department of Nutritional Science & Toxicology, University of California, Berkeley, California, United States of America
| | - Oleg Mayba
- Department of Statistics, University of California, Berkeley, California, United States of America
| | - Joyce V. Lee
- Department of Nutritional Science & Toxicology, University of California, Berkeley, California, United States of America
| | - Joanna Tran
- Department of Nutritional Science & Toxicology, University of California, Berkeley, California, United States of America
| | - Charlie Harris
- Department of Medicine, Gladstone Institute of Cardiovascular Disease, Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Terence P. Speed
- Department of Statistics, University of California, Berkeley, California, United States of America
| | - Jen-Chywan Wang
- Department of Nutritional Science & Toxicology, University of California, Berkeley, California, United States of America
- Department of Medicine, Gladstone Institute of Cardiovascular Disease, Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Hughes KA, Reynolds RM, Andrew R, Critchley HOD, Walker BR. Glucocorticoids turn over slowly in human adipose tissue in vivo. J Clin Endocrinol Metab 2010; 95:4696-702. [PMID: 20631029 PMCID: PMC4394154 DOI: 10.1210/jc.2010-0384] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Lipophilic plasma glucocorticoids are thought to gain rapid access to intracellular compartments in adipose tissue. In other organs, transport can be regulated in a steroid- and tissue-specific manner. Moreover, 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) generates additional cortisol within adipose. AIM The aim was to measure the rate of exchange of cortisol between plasma and adipose for comparison with rates of intracellular cortisol generation by 11βHSD1. PARTICIPANTS AND INTERVENTIONS With ethical approval, otherwise healthy females (n = 6) undergoing hysterectomy for benign indications were infused with tracer 9,11,12,12-[(2)H](4)cortisol (d4-cortisol). Adipose biopsies and peripheral venous samples were obtained during surgery after 3.9-5.5 h of infusion. Glucocorticoids were quantified using liquid chromatography tandem mass spectrometry. RESULTS In plasma, d4-cortisol concentrations and appearance rates of cortisol and d3-cortisol (reflecting 11βHSD1 activity) did not change during surgery. In both omental and sc adipose, cortisol concentrations were lower than in plasma, consistent with differences in corticosteroid binding globulin, and enrichment with d4-cortisol was low (sc, 7.2 ± 0.6%; omental, 7.4 ± 0.7%; vs. plasma, 15.5 ± 1.0%). The rate of accumulation of d4-cortisol in adipose depots was 0.5 ± 0.1 (sc) and 0.4 ± 0.1 (omental) nmol/kg · h, and the proportion of intraadipose cortisol replaced each hour only 10.7 ± 1.0 and 10.4 ± 0.7%, respectively. The contribution of 11βHSD1 to this turnover could not be quantified because very little substrate d3-cortisone accumulated in adipose during infusion. CONCLUSIONS Slow turnover of the adipose glucocorticoid pool suggests that rapid acute fluctuations in circulating cortisol are not reflected in adipose, so that 11βHSD1 activity (previously estimated to generate 9 nmol cortisol/kg · h in sc adipose) may play a relatively important role in modulating activation of glucocorticoid receptors.
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Affiliation(s)
- Katherine A Hughes
- Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, Edinburgh, United Kingdom
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Dolgos S, Hartmann A, Jenssen T, Isaksen GA, Pfeffer P, Bollerslev J. Determinants of short-term changes in body composition following renal transplantation. ACTA ACUST UNITED AC 2009; 43:76-83. [DOI: 10.1080/00365590802273226] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | | | - Trond Jenssen
- Medical Department, Section of Nephrology
- Medical Faculty, Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
| | | | - Per Pfeffer
- Department of Transplantation Surgery, Rikshospitalet University Hospital, University of Oslo, Oslo, Norway
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Abstract
The activity of the pituitary-adrenal axis can profoundly impact on body composition. This is dramatically seen in Cushing's syndrome (CS) but changes in body composition are also implicated in depression and alcoholic pseudocushing's. The pathophysiological mechanisms underlying these changes remain poorly understood. Changes to body composition in CS include increased fat mass, decreased bone mass, thinning of the skin and reduced lean mass. Why these tissues are affected so dramatically is unclear. Additionally, the change in body composition between individuals varies considerably for reasons which are only now becoming evident. This paper reviews the phenotypic changes with altered pituitary-adrenal axis activity and discusses the mechanisms involved. The primary focus is on adipose, bone, muscle and skin since the most dramatic changes are seen in these tissues.
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Affiliation(s)
- Eva Fernandez-Rodriguez
- Division of Medical Sciences, The Institute of Biomedical Research, The Medical School, The University of Birmingham, Birmingham , B15 2TH, UK
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25
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Bujalska IJ, Hewitt KN, Hauton D, Lavery GG, Tomlinson JW, Walker EA, Stewart PM. Lack of hexose-6-phosphate dehydrogenase impairs lipid mobilization from mouse adipose tissue. Endocrinology 2008; 149:2584-91. [PMID: 18218694 PMCID: PMC2329282 DOI: 10.1210/en.2007-1705] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In adipose tissue, glucocorticoids regulate lipogenesis and lipolysis. Hexose-6-phosphate dehydrogenase (H6PDH) is an enzyme located in the endoplasmic reticulum that provides a cofactor for the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), regulating the set point of its activity and allowing for tissue-specific activation of glucocorticoids. The aim of this study was to examine the adipose tissue biology of the H6PDH null (H6PDH/KO) mouse. Real-time PCR analysis confirmed similar mRNA levels of 11beta-HSD1 and glucocorticoid receptor-alpha in wild-type (WT) and H6PDH/KO mice in liver and gonadal fat depots. Microsomal 11beta-HSD1 protein levels shown by Western blot analysis corresponded well with mRNA expression in gonadal fat of WT and H6PDH/KO mice. Despite this, the enzyme directionality in these tissues changed from predominately oxoreductase in WT to exclusively dehydrogenase activity in the H6PDH/KO mice. In the fed state, H6PDH/KO mice had reduced adipose tissue mass, but histological examination revealed no difference in average adipocyte size between genotypes. mRNA expression levels of the key lipogenic enzymes, acetyl CoA carboxylase, adiponutrin, and stearoyl-coenzyme A desaturase-2, were decreased in H6PDH/KO mice, indicative of impaired lipogenesis. In addition, lipolysis rates were also impaired in the H6PDH/KO as determined by lack of mobilization of fat and no change in serum free fatty acid concentrations upon fasting. In conclusion, in the absence of H6PDH, the set point of 11beta-HSD1 enzyme activity is switched from predominantly oxoreductase to dehydrogenase activity in adipose tissue; as a consequence, this leads to impairment of fat storage and mobilization.
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Affiliation(s)
- Iwona J Bujalska
- Division of medical Sciences (Medicine), University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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Verhaeghe J, Vanstapel F, Van Bree R, Van Herck E, Coopmans W. Transient catabolic state with reduced IGF-I after antenatal glucocorticoids. Pediatr Res 2007; 62:295-300. [PMID: 17622956 DOI: 10.1203/pdr.0b013e318123f72f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Glucocorticoid (GC) administration before preterm birth reduces neonatal morbidity but may restrain growth. Here we explored the effect of antenatal GC on nutrient substrates [glucose, FFA, amino acids (AA)], and on IGF-I and IGF-binding protein-1 (IGFBP-1). We analyzed umbilical vein (UV) plasma obtained at birth from 91 preterm newborns that received one course of GC (last exposure 1-1358 h before birth) and 49 newborns that did not. We found that recent GC exposure (-48 h) raised glucose, FFA, and AA concentrations, and the homeostasis model assessment of insulin resistance (HOMA-IR) index, but lowered IGF-I concentrations. The AA surge was greater in newborns with a birth weight z score <0 than in those with a z score >0. Although all AA were transiently increased, the increment was most robust for glutamine and alanine. Shorter duration since GC administration and lower IGF-I concentrations independently predicted AA levels. In conclusion, an antenatal course of GC elicited a transient catabolic state encompassing all nutrient substrates, and a temporary drop in IGF-I concentrations. These changes may explain the growth-inhibitory effects of repeated antenatal GC administration. Future research should clarify the role of IGF-I in the protein-catabolic response to GC.
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Affiliation(s)
- Johan Verhaeghe
- Department of Obstetrics and Gynecology, Health Campus Gasthuisberg, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
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Christiansen JJ, Djurhuus CB, Gravholt CH, Iversen P, Christiansen JS, Schmitz O, Weeke J, Jørgensen JOL, Møller N. Effects of cortisol on carbohydrate, lipid, and protein metabolism: studies of acute cortisol withdrawal in adrenocortical failure. J Clin Endocrinol Metab 2007; 92:3553-9. [PMID: 17609300 DOI: 10.1210/jc.2007-0445] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CONTEXT Cortisol is an important catabolic hormone, but little is known about the metabolic effects of acute cortisol deficiency. OBJECTIVE The objective of the study was to test whether clinical symptoms of weight loss, fatigue, and hypoglycemia could be explained by altered energy expenditure, protein metabolism, and insulin sensitivity during cortisol withdrawal in adrenocortical failure. DESIGN, PARTICIPANTS, AND INTERVENTION We studied seven women after 24-h cortisol withdrawal and during replacement control during a 3-h basal period and a 3-h glucose clamp. RESULTS Cortisol withdrawal generated cortisol levels close to zero, a 10% decrease in basal energy expenditure, increased TSH and T(3) levels, and increased glucose oxidation. Whole-body glucose and phenylalanine turnover were unaltered, but forearm phenylalanine turnover was increased. During the clamp glucose, infusion rates rose by 70%, glucose oxidation rates increased, and endogenous glucose production decreased. Urinary urea excretion decreased by 40% over the 6-h study period. CONCLUSIONS Cortisol withdrawal increased insulin sensitivity in terms of increased glucose oxidation and decreased endogenous glucose production; this may induce hypoglycemia in adrenocortical failure. Energy expenditure and urea loss decreased, indicating that weight and muscle loss in Addison's disease is caused by other mechanisms, such as decreased appetite. Increased muscle protein breakdown may amplify the loss of muscle protein.
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Affiliation(s)
- Jens Juel Christiansen
- Medical Department M, Aarhus Sygehus NBG, Arhus University Hospital, DK-8000 C Arhus, Denmark.
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Burt MG, Gibney J, Ho KKY. Protein metabolism in glucocorticoid excess: study in Cushing's syndrome and the effect of treatment. Am J Physiol Endocrinol Metab 2007; 292:E1426-32. [PMID: 17244724 DOI: 10.1152/ajpendo.00524.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
How protein metabolism is perturbed during chronic glucocorticoid excess is poorly understood. The aims were to investigate the impact of chronic glucocorticoid excess and restoration of eucortisolemia in Cushing's syndrome (CS) on whole body protein metabolism. Eighteen subjects with CS and 18 normal subjects (NS) underwent assessment of body composition using DEXA and whole body protein turnover with a 3-h constant infusion of l-[(13)C]leucine, allowing calculation of rates of leucine appearance (leucine R(a)), leucine oxidation (L(ox)), and leucine incorporation into protein (LIP). Ten subjects with CS were restudied after restoration of eucortisolemia. Percentage FM was greater (43.9 +/- 1.6 vs. 33.8 +/- 2.4%, P = 0.002) and LBM lower (52.7 +/- 1.6 vs. 62.1 +/- 2.3%, P = 0.002) in CS. LBM was significantly correlated (r(2) > 0.44, P < 0.005) to leuceine R(a), L(ox), and LIP in both groups. After correcting for LBM, leucine R(a) (133 +/- 5 vs. 116 +/- 5 micromol/min, P = 0.02) and L(ox) (29 +/- 1 vs. 24 +/- 1 micromol/min, P = 0.01) were greater in CS. FM significantly correlated (r(2) = 0.23, P < 0.05) with leucine R(a) and LIP, but not L(ox) in CS. In multiple regression, LBM was an independent determinant of all three indexes of leucine turnover, FM of leucine R(a), and LIP and CS of L(ox). Following restoration of eucortisolemia, L(ox) was reduced (Delta-7.5 +/- 2.6 micromol/min, P = 0.02) and LIP increased (Delta+15.2 +/- 6.2 micromol/min, P = 0.04). In summary, whole body protein metabolism in CS is influenced by changes in body composition and glucocorticoid excess per se, which increases protein oxidation. Enhanced protein oxidation is a likely explanation for the reduced protein mass in CS. Successful treatment of CS reduces protein oxidation and increases protein synthesis to prevent ongoing protein loss.
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Affiliation(s)
- Morton G Burt
- Pituitary Research Unit, Garvan Institute of Medical Research, New South Wales, Australia
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Burt MG, Gibney J, Ho KKY. Characterization of the metabolic phenotypes of Cushing's syndrome and growth hormone deficiency: a study of body composition and energy metabolism. Clin Endocrinol (Oxf) 2006; 64:436-43. [PMID: 16584517 DOI: 10.1111/j.1365-2265.2006.02488.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE A comparison of the severity and distribution of perturbations in body composition and their relationship to energy metabolism in glucocorticoid excess and GH deficiency (GHD) has not been undertaken before. The aim of this study was to investigate the impact of Cushing's syndrome (CS) and GHD on whole and regional body composition and energy metabolism. DESIGN Cross-sectional study design. PATIENTS Eighteen subjects with CS (12 women, aged = 41.5 +/- 3.0 years, 24-h urinary free cortisol = 1601 +/- 361 nmol/day, normal < 300 nmol/day), 22 subjects with GHD (14 women, age = 42.9 +/- 2.9 years) and 18 normal subjects (11 women, age = 46.8 +/- 2.8 years). MEASUREMENTS Lean body mass (LBM), fat mass (FM) and regional body composition were assessed by dual-energy X-ray absorptiometry (DEXA). Resting energy expenditure (REE) and fat oxidation (Fox) were assessed by indirect calorimetry. RESULTS Mean percentage FM was significantly greater by 30% in CS (P = 0.002) and 22% in GH-deficient subjects (P = 0.014) than in normal subjects. LBM was significantly lower by 15% in CS (P = 0.002) and 11% in GHD (P = 0.013). In CS, the proportion of lean tissue in the limbs was 12% less than in normal (P = 0.001) and GH-deficient subjects (P = 0.0005). Truncal fat represented a greater proportion of total FM in CS (52.5 +/- 1.8%vs. 46.9 +/- 1.3%, P = 0.014) than in normal subjects, but not in GHD. REE and Fox, corrected for LBM, were significantly lower in GHD (P < 0.02 for both vs. normal) but not in CS. CONCLUSION FM was higher and LBM lower in both CS and GHD. However, there is a greater abnormality of regional body composition in patients with CS who exhibit a lower limb lean mass and a greater truncal fat. Reduced REE and Fox contribute to increased adiposity in GHD. As REE and Fox are not perturbed in CS, other mechanisms must explain the marked gain in truncal and total fat.
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Affiliation(s)
- Morton G Burt
- Pituitary Research Unit, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
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Abstract
For a long time neural and endocrine messages were studied for their impact on adipocyte metabolism and control of storage/release of fatty acids. In fact, bidirectional communication exists between adipocytes and other tissues. Several molecules secreted from adipocytes are involved in fat cell signaling to other tissues. Adipocyte products could initiate antagonistic effects on target tissues. Fat cells produce peptides that can elicit insulin resistance, such as tumor necrosis factor-alpha and resistin, as well as hormones that can improve insulin resistance, such as leptin and adiponectin. Secretion of complement proteins, proinflammatory cytokines, procoagulant, and acute phase reactant proteins have also been observed in adipocytes. There is much to learn about how these signals function. It is unlikely that all the adipocyte's endocrine and paracrine signals have been identified. Putative pharmacological strategies aiming at modulation of afferent and efferent fat cell messages are reviewed and discussed.
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Affiliation(s)
- Max Lafontan
- Obesity Research Unit, French Institute of Health and Medical Research (Inserm-UPS-Unit 586), Université Paul Sabatier, Institut Louis Bugnard, Hôpital Rangueil, TSA50032, 31059 Toulouse cedex 9, France.
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