1
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Peterson TE, Lima JAC, Shah SJ, Bluemke DA, Bertoni AG, Liu Y, Ngo D, Varadarajan V, Mychaleckyj JC, Johnson CW, Psaty BM, Clish CB, Taylor KD, Durda P, Tracy RP, Gerszten RE, Rich SS, Rotter JI, Post WS, Pankow JS. Proteomics of left ventricular structure in the Multi-Ethnic Study of Atherosclerosis. ESC Heart Fail 2024. [PMID: 39263947 DOI: 10.1002/ehf2.15073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 08/12/2024] [Accepted: 08/26/2024] [Indexed: 09/13/2024] Open
Abstract
AIMS Proteomic profiling offers an expansive approach to biomarker discovery and mechanistic hypothesis generation for LV remodelling, a critical component of heart failure (HF). We sought to identify plasma proteins cross-sectionally associated with left ventricular (LV) size and geometry in a diverse population-based cohort without known cardiovascular disease (CVD). METHODS AND RESULTS Among participants of the Multi-Ethnic Study of Atherosclerosis (MESA), we quantified plasma abundances of 1305 proteins using an aptamer-based platform at exam 1 (2000-2002) and exam 5 (2010-2011) and assessed LV structure by cardiac magnetic resonance (CMR) at the same time points. We used multivariable linear regression with robust variance to assess cross-sectional associations between plasma protein abundances and LV structural characteristics at exam 1, reproduced findings in later-life at exam 5, and explored relationships of associated proteins using annotated enrichment analysis. We studied 763 participants (mean age 60 ± 10 years at exam 1; 53% female; 19% Black race; 31% Hispanic ethnicity). Following adjustment for renal function and traditional CVD risk factors, plasma levels of 3 proteins were associated with LV mass index at both time points with the same directionality (FDR < 0.05): leptin (LEP), renin (REN), and cathepsin-D (CTSD); 20 with LV end-diastolic volume index: LEP, NT-proBNP, histone-lysine N-methyltransferase (EHMT2), chordin-like protein 1 (CHRDL1), tumour necrosis factor-inducible gene 6 protein (TNFAIP6), NT-3 growth factor receptor (NTRK3), c5a anaphylatoxin (C5), neurogenic locus notch homologue protein 3 (NOTCH3), ephrin-B2 (EFNB2), osteomodulin (OMD), contactin-4 (CNTN4), gelsolin (GSN), stromal cell-derived factor 1 (CXCL12), calcineurin subunit B type 1 (PPP3R1), insulin-like growth factor 1 receptor (IGF1R), bone sialoprotein 2 (IBSP), interleukin-11 (IL-11), follistatin-related protein 1 (FSTL1), periostin (POSTN), and biglycan (BGN); and 4 with LV mass-to-volume ratio: RGM domain family member B (RGMB), transforming growth factor beta receptor type 3 (TGFBR3), ephrin-A2 (EFNA2), and cell adhesion molecule 3 (CADM3). Functional annotation implicated regulation of the PI3K-Akt pathway, bone morphogenic protein signalling, and cGMP-mediated signalling. CONCLUSIONS We report proteomic profiling of LV size and geometry, which identified novel associations and reinforced previous findings on biomarker candidates for LV remodelling and HF. If validated, these proteins may help refine risk prediction and identify novel therapeutic targets for HF.
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Grants
- 75N92020D00001 NHLBI NIH HHS
- HHSN268201500003I NHLBI NIH HHS
- N01-HC-95159 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00005 NHLBI NIH HHS
- N01-HC-95160 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00002 NHLBI NIH HHS
- N01-HC-95161 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00003 NHLBI NIH HHS
- N01-HC-95162 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00006 NHLBI NIH HHS
- N01-HC-95163 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00004 NHLBI NIH HHS
- N01-HC-95164 National Heart, Lung, and Blood Institute (NHLBI)
- 75N92020D00007 NHLBI NIH HHS
- N01-HC-95165 National Heart, Lung, and Blood Institute (NHLBI)
- N01-HC-95166 National Heart, Lung, and Blood Institute (NHLBI)
- N01-HC-95167 National Heart, Lung, and Blood Institute (NHLBI)
- N01-HC-95168 National Heart, Lung, and Blood Institute (NHLBI)
- N01-HC-95169 National Heart, Lung, and Blood Institute (NHLBI)
- UL1-TR-000040 National Heart, Lung, and Blood Institute (NHLBI)
- UL1-TR-001079 National Heart, Lung, and Blood Institute (NHLBI)
- UL1-TR-001420 National Heart, Lung, and Blood Institute (NHLBI)
- UL1TR001881 National Heart, Lung, and Blood Institute (NHLBI)
- DK063491 National Heart, Lung, and Blood Institute (NHLBI)
- R01HL105756 National Heart, Lung, and Blood Institute (NHLBI)
- T32 HL007779 NHLBI NIH HHS
- T32 HL007227 NHLBI NIH HHS
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Affiliation(s)
- Tess E Peterson
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joao A C Lima
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Sanjiv J Shah
- Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - David A Bluemke
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Alain G Bertoni
- Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Yongmei Liu
- Department of Medicine, Cardiology and Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - Debby Ngo
- Division of Cardiovascular Medicine, Beth Israel Deaconess Hospital, Boston, Massachusetts, USA
| | - Vinithra Varadarajan
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Josyf C Mychaleckyj
- Department of Genome Sciences, University of Virginia, Charlottesville, Virginia, USA
| | - Craig W Johnson
- Department of Biostatistics, University of Washington, Seattle, Washington, USA
| | - Bruce M Psaty
- Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Systems and Population Health, University of Washington, Seattle, Washington, USA
| | - Clary B Clish
- Metabolomics Platform, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Washington, USA
| | - Kent D Taylor
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Peter Durda
- Department of Pathology & Laboratory Medicine, University of Vermont, Colchester, Vermont, USA
| | - Russell P Tracy
- Department of Pathology & Laboratory Medicine, University of Vermont, Colchester, Vermont, USA
| | - Robert E Gerszten
- Division of Cardiovascular Medicine, Beth Israel Deaconess Hospital, Boston, Massachusetts, USA
| | - Stephen S Rich
- Department of Genome Sciences, University of Virginia, Charlottesville, Virginia, USA
| | - Jerome I Rotter
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Wendy S Post
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - James S Pankow
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
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2
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Suárez-Mesa R, Ros-Freixedes R, Pena RN, Reixach J, Estany J. Impact of the leptin receptor gene on pig performance and quality traits. Sci Rep 2024; 14:10652. [PMID: 38730110 PMCID: PMC11087582 DOI: 10.1038/s41598-024-61509-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024] Open
Abstract
The recessive T allele of the missense polymorphism rs709596309 C > T of the leptin receptor gene is associated with intramuscular fat. However, its overall impact on pork production is still partial. In this work, we investigated the all-round effects of the TT genotype on lean growth efficiency and carcass, meat and fat quality using data from an experiment that compared the performance of 48 TT and 48 C- (24 CT and 24 CC) Duroc barrows. The TT pigs were less efficient for lean growth than the C- pigs. Although heavier, their carcasses had less lean content, were shorter and had lighter loins. Apart from increasing marbling and saturated fatty acid content, changes caused by the TT genotype in meat and fat quality are likely not enough to be perceived by consumers. The effect on visual marbling score exceeded that on intramuscular fat content, which suggests a direct influence of the T allele on the pattern of fat distribution in muscle. With current low-protein diets, the T allele is expected to be cost-effective only in niche markets where a very high level of marbling is critical.
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Affiliation(s)
- Rafael Suárez-Mesa
- Department of Animal Science, University of Lleida - Agrotecnio-CERCA Center, 191 Rovira Roure, 25198, Lleida, Catalonia, Spain
| | - Roger Ros-Freixedes
- Department of Animal Science, University of Lleida - Agrotecnio-CERCA Center, 191 Rovira Roure, 25198, Lleida, Catalonia, Spain
| | - Ramona N Pena
- Department of Animal Science, University of Lleida - Agrotecnio-CERCA Center, 191 Rovira Roure, 25198, Lleida, Catalonia, Spain
| | - Josep Reixach
- Selección Batallé S.A., 17421, Riudarenes, Catalonia, Spain
| | - Joan Estany
- Department of Animal Science, University of Lleida - Agrotecnio-CERCA Center, 191 Rovira Roure, 25198, Lleida, Catalonia, Spain.
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3
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Peng C, Xiao P, Li N. Does oncolytic viruses-mediated metabolic reprogramming benefit or harm the immune microenvironment? FASEB J 2024; 38:e23450. [PMID: 38294796 DOI: 10.1096/fj.202301947rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/11/2023] [Accepted: 01/11/2024] [Indexed: 02/01/2024]
Abstract
Oncolytic virus immunotherapy as a new tumor therapy has made remarkable achievements in clinical practice. And metabolic reprogramming mediated by oncolytic virus has a significant impact on the immune microenvironment. This review summarized the reprogramming of host cell glucose metabolism, lipid metabolism, oxidative phosphorylation, and glutamine metabolism by oncolytic virus and illustrated the effects of metabolic reprogramming on the immune microenvironment. It was found that oncolytic virus-induced reprogramming of glucose metabolism in tumor cells has both beneficial and detrimental effects on the immune microenvironment. In addition, oncolytic virus can promote fatty acid synthesis in tumor cells, inhibit oxidative phosphorylation, and promote glutamine catabolism, which facilitates the anti-tumor immune function of immune cells. Therefore, targeted metabolic reprogramming is a new direction to improve the efficacy of oncolytic virus immunotherapy.
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Affiliation(s)
- Chengcheng Peng
- Institute of Virology, Wenzhou University, Wenzhou, China
- Key Laboratory of Virology and Immunology of Wenzhou, Wenzhou University, Wenzhou, China
| | - Pengpeng Xiao
- Institute of Virology, Wenzhou University, Wenzhou, China
- Key Laboratory of Virology and Immunology of Wenzhou, Wenzhou University, Wenzhou, China
| | - Nan Li
- Institute of Virology, Wenzhou University, Wenzhou, China
- Key Laboratory of Virology and Immunology of Wenzhou, Wenzhou University, Wenzhou, China
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4
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Engin A. The Mechanism of Leptin Resistance in Obesity and Therapeutic Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1460:463-487. [PMID: 39287862 DOI: 10.1007/978-3-031-63657-8_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Leptin resistance is induced via leptin signaling blockade by chronic overstimulation of the leptin receptor and intracellular signaling defect or increased hypothalamic inflammation and suppressor of cytokine signaling (SOCS)-3 expression. High-fat diet triggers leptin resistance induced by at least two independent causes: first, the limited ability of peripheral leptin to activate hypothalamic signaling transducers and activators of transcription (STAT) signaling and secondly a signaling defect in leptin-responsive hypothalamic neurons. Central leptin resistance is dependent on decreased leptin transport efficiency across the blood brain barrier (BBB) rather than hypothalamic leptin insensitivity. Since the hypothalamic phosphorylated STAT3 (pSTAT3) represents a sensitive and specific readout of leptin receptor-B signaling, the assessment of pSTAT3 levels is the gold standard. Hypertriglyceridemia is one of important factors to inhibit the transport of leptin across BBB in obesity. Mismatch between high leptin and the amount of leptin receptor expression in obesity triggers brain leptin resistance via increasing hypothalamic inflammation and SOCS-3 expression. Therapeutic strategies that regulate the passage of leptin to the brain include the development of modifications in the structure of leptin analogues as well as the synthesis of new leptin receptor agonists with increased BBB permeability. In the hyperleptinemic state, polyethylene glycol (PEG)-modified leptin is unable to pass through the BBB. Peripheral histone deacetylase (HDAC) 6 inhibitor, tubastatin, and metformin increase central leptin sensitization. While add-on therapy with anagliptin, metformin and miglitol reduce leptin concentrations, the use of long-acting leptin analogs, and exendin-4 lead to the recovery of leptin sensitivity. Contouring surgery with fat removal, and bariatric surgery independently of the type of surgery performed provide significant improvement in leptin concentrations. Although approaches to correcting leptin resistance have shown some success, no clinically effective application has been developed to date. Due to the impairment of central and peripheral leptin signaling, as well as the extensive integration of leptin-sensitive metabolic pathways with other neurons, the effectiveness of methods used to eliminate leptin resistance is extremely limited.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey.
- Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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5
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Choi HN, Lim H, Kim YS, Rhee SY, Yim JE. Differences of Regional Fat Distribution Measured by Magnetic Resonance Imaging According to Obese Phenotype in Koreans. Metab Syndr Relat Disord 2022; 20:551-557. [PMID: 36269325 DOI: 10.1089/met.2022.0044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background: Obesity is commonly associated with a high risk of metabolic disorders, and obesity-related metabolic abnormalities are affected by some specific obesity phenotypes, regional fat distribution, and body mass index. However, few studies have investigated the relationship between obesity phenotypes and regional fat distribution in Korean subjects. This study aimed to assess regional fat distribution by gender using magnetic resonance imaging (MRI), and to identify a link between fat distribution and metabolic disorders in Korean subjects. Methods: This study included 35 Korean subjects (20 women, 15 men) who were classified into two groups by gender, and further divided into two groups based on their obesity phenotype: a metabolically abnormal obesity (MAO) and metabolically healthy obesity (MHO) group. Fat distribution was measured using MRI. The blood parameters were measured using a commercially available kit. Results: Women in the MAO group had more risk factors for metabolic abnormalities than those in the MHO group. Serum glucose, triglyceride, and high-density lipoprotein cholesterol (HDL-C) levels were also significantly higher in women with MAO than in those with MHO. The intermuscular adipose tissue (IMAT) of women with MAO was significantly higher than that of women with MHO. Serum HDL-C level was negatively correlated with IMAT, whereas leptin showed a positive correlation with IMAT in all subjects. Conclusions: Metabolic abnormalities according to obesity phenotype posed a higher risk in women than that in men. These findings suggest that an understanding of gender differences in relation to the association between obesity and metabolic risk would be helpful to reduce the prevalence of obesity.
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Affiliation(s)
- Ha-Neul Choi
- Department of Food and Nutrition, Changwon National University, Changwon, Korea
| | - Hyunjung Lim
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yong-in, Korea.,Research Institute of Medical Nutrition, Kyung Hee University, Seoul, Korea
| | - Young-Seol Kim
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Sang-Youl Rhee
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Seoul, Korea
| | - Jung-Eun Yim
- Department of Food and Nutrition, Changwon National University, Changwon, Korea.,Interdisciplinary Program in Senior Human Ecology (BK21 Four Program), Changwon National University, Changwon, Korea
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6
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Sheng CY, Son YH, Jang J, Park SJ. In vitro skeletal muscle models for type 2 diabetes. BIOPHYSICS REVIEWS 2022; 3:031306. [PMID: 36124295 PMCID: PMC9478902 DOI: 10.1063/5.0096420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Type 2 diabetes mellitus, a metabolic disorder characterized by abnormally elevated blood sugar, poses a growing social, economic, and medical burden worldwide. The skeletal muscle is the largest metabolic organ responsible for glucose homeostasis in the body, and its inability to properly uptake sugar often precedes type 2 diabetes. Although exercise is known to have preventative and therapeutic effects on type 2 diabetes, the underlying mechanism of these beneficial effects is largely unknown. Animal studies have been conducted to better understand the pathophysiology of type 2 diabetes and the positive effects of exercise on type 2 diabetes. However, the complexity of in vivo systems and the inability of animal models to fully capture human type 2 diabetes genetics and pathophysiology are two major limitations in these animal studies. Fortunately, in vitro models capable of recapitulating human genetics and physiology provide promising avenues to overcome these obstacles. This review summarizes current in vitro type 2 diabetes models with focuses on the skeletal muscle, interorgan crosstalk, and exercise. We discuss diabetes, its pathophysiology, common in vitro type 2 diabetes skeletal muscle models, interorgan crosstalk type 2 diabetes models, exercise benefits on type 2 diabetes, and in vitro type 2 diabetes models with exercise.
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Affiliation(s)
- Christina Y. Sheng
- Biohybrid Systems Group, Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Young Hoon Son
- Biohybrid Systems Group, Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | - Sung-Jin Park
- Biohybrid Systems Group, Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University School of Medicine, Atlanta, Georgia 30322, USA
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7
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Liu J, Lai F, Hou Y, Zheng R. Leptin signaling and leptin resistance. MEDICAL REVIEW (BERLIN, GERMANY) 2022; 2:363-384. [PMID: 37724323 PMCID: PMC10388810 DOI: 10.1515/mr-2022-0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/12/2022] [Indexed: 09/20/2023]
Abstract
With the prevalence of obesity and associated comorbidities, studies aimed at revealing mechanisms that regulate energy homeostasis have gained increasing interest. In 1994, the cloning of leptin was a milestone in metabolic research. As an adipocytokine, leptin governs food intake and energy homeostasis through leptin receptors (LepR) in the brain. The failure of increased leptin levels to suppress feeding and elevate energy expenditure is referred to as leptin resistance, which encompasses complex pathophysiological processes. Within the brain, LepR-expressing neurons are distributed in hypothalamus and other brain areas, and each population of the LepR-expressing neurons may mediate particular aspects of leptin effects. In LepR-expressing neurons, the binding of leptin to LepR initiates multiple signaling cascades including janus kinase (JAK)-signal transducers and activators of transcription (STAT) phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT), extracellular regulated protein kinase (ERK), and AMP-activated protein kinase (AMPK) signaling, etc., mediating leptin actions. These findings place leptin at the intersection of metabolic and neuroendocrine regulations, and render leptin a key target for treating obesity and associated comorbidities. This review highlights the main discoveries that shaped the field of leptin for better understanding of the mechanism governing metabolic homeostasis, and guides the development of safe and effective interventions to treat obesity and associated diseases.
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Affiliation(s)
- Jiarui Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Futing Lai
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Yujia Hou
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
- Neuroscience Research Institute, Peking University, Beijing, China
- Key Laboratory for Neuroscience of Ministry of Education, Peking University, Beijing, China
- Key Laboratory for Neuroscience of National Health Commission, Peking University, Beijing 100191, China
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8
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Vargas-Rosvik S, Lazo-Verdugo N, Escandón S, Ochoa-Avilés C, Baldeón-Rojas L, Ochoa-Avilés A. Cardiovascular risk among 6-8-year-old children living in urban and rural communities in Ecuador: A cross-sectional analysis. Front Nutr 2022; 9:925873. [PMID: 35967818 PMCID: PMC9366330 DOI: 10.3389/fnut.2022.925873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
Cardiovascular diseases have their origins in childhood. At least 20% of children and adolescents in Latin America are overweight or obese. However, little is known regarding the cardiovascular risk of young children living in the region. This paper aims to identify associations between socio-demographics, adiposity, and dietary intake with cardiometabolic risk among children between 6- and 8-years old living in urban and rural Andean regions of Ecuador. A cross-sectional study was conducted among 267 children attending elementary schools between February and August 2018. Sociodemographic data were collected using a structured interview. Bodyweight, height, and waist circumference were measured in duplicate; blood samples were taken after overnight fasting to determine blood lipids, hepatic enzymes, and adipokines; food intake data was assessed by two 24-h recalls administered to the guardians. Associations between cardiometabolic risk (i.e., blood lipids, hepatic enzymes, and adipokines) with sociodemographic characteristics, dietary intake, and waist circumference were tested using multiple hierarchical regression models. Twenty-nine percent of the children were overweight or obese, 12% had low HDL levels, and over 18% had high levels of LDL and triglycerides. Children living in the urban region had lower levels of HDL (β-4.07 mg/dL; 95% CI: -7.00; -1.15; P = 0.007) but higher levels of LDL cholesterol (β 8.52 mg/dL; 95% CI: 1.38; 15.66; P = 0.019). Hepatic enzymes were also higher among urban children (SGOT: β% 22.13; 95% CI: 17.33; 26.93; P < 0.001; SGPT: β 0.84 U/L; 95% CI: 0.09; 1.59; P = 0.028). Leptin blood levels were higher (β% 29.27; 95% CI: 3.57; 54.97; P = 0.026), meanwhile adiponectin plasma concentrations were lower among urban children (β%-103.24; 95% CI: -58.9; -147.58; P = < 0.001). Fiber intake was inversely associated with total cholesterol (β-9.27 mg/dL; 95% CI -18.09; -0.45; P = 0.040) and LDL cholesterol blood levels (β-9.99 mg/dL; 95% CI: -18.22; -1.75; P = 0.018). Our findings demonstrate that young children are at high cardiovascular risk; if no actions are taken, the burden of non-communicable diseases will be substantial. The differences in risk between rural and urban areas are evident; urbanization might predispose children to a different reality and, in most cases, result in poor habits.
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Affiliation(s)
| | | | - Samuel Escandón
- Departamento de Biociencias, Universidad de Cuenca, Cuenca, Ecuador
| | | | - Lucy Baldeón-Rojas
- Instituto de Investigación en Biomedicina, Universidad Central del Ecuador, Quito, Ecuador
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9
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Venojärvi M, Lindström J, Aunola S, Nuutila P, Atalay M. Improved Aerobic Capacity and Adipokine Profile Together with Weight Loss Improve Glycemic Control without Changes in Skeletal Muscle GLUT-4 Gene Expression in Middle-Aged Subjects with Impaired Glucose Tolerance. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19148327. [PMID: 35886175 PMCID: PMC9320448 DOI: 10.3390/ijerph19148327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/01/2022] [Accepted: 07/04/2022] [Indexed: 11/26/2022]
Abstract
(1) Objective: The aim of this study was to clarify the role of adipokines in the regulation of glucose metabolism in middle-aged obese subjects with impaired glucose tolerance in response to a long-term exercise and dietary intervention. (2) Methods: Skeletal muscle, plasma and serum samples were examined in 22 subjects from an exercise−diet intervention study aiming to prevent type 2 diabetes. The subjects were further divided into two subgroups (non-responders n = 9 and responders n = 13) based on their achievement in losing at least 3 kg. (3) Results: The two-year exercise−diet intervention reduced leptin levels and increased adiponectin levels in responders; the changes in leptin levels were significantly associated with changes in their weights (r = 0.662, p < 0.01). In responders, insulin sensitivity (Bennett and McAuley index) increased and was associated with changes in maximal oxygen uptake (VO2peak) (r = 0.831, p < 0.010 and r = 0.890, p < 0.01). In addition, the VO2peak and oxidative capacity of skeletal muscle improved in responders, but not in non-responders. However, there were no changes between the two groups in expressions of the glucose transporter protein-4 (GLUT-4) gene or of AMP-activated protein kinase (AMPK)-α1 or AMPK-α2 proteins. (4) Conclusions: The exercise−diet intervention decreased serum leptin and increased serum adiponectin concentrations, improved glucose control without affecting GLUT-4 gene expression in the skeletal muscle in responders.
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Affiliation(s)
- Mika Venojärvi
- Institute of Biomedicine, Sport and Exercise Medicine, University of Eastern Finland, 70210 Kuopio, Finland
- Correspondence:
| | - Jaana Lindström
- Population Health Unit, Department of Public Health and Welfare, Finnish Institute for Health and Welfare, 00271 Helsinki, Finland;
| | - Sirkka Aunola
- Functional Capacity Unit, Department of Health, Functional Capacity and Welfare, National Institute for Health and Welfare, 20740 Turku, Finland;
| | - Pirjo Nuutila
- PET Centre, University of Turku, 20500 Turku, Finland;
| | - Mustafa Atalay
- Institute of Biomedicine, Physiology, University of Eastern Finland, 70210 Kuopio, Finland;
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10
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Gilloteaux J, Nicaise C, Sprimont L, Bissler J, Finkelstein JA, Payne WR. Leptin receptor defect with diabetes causes skeletal muscle atrophy in female obese Zucker rats where peculiar depots networked with mitochondrial damages. Ultrastruct Pathol 2021; 45:346-375. [PMID: 34743665 DOI: 10.1080/01913123.2021.1983099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Tibialis anterior muscles of 45-week-old female obese Zucker rats with defective leptin receptor and non-insulin dependent diabetes mellitus (NIDDM) showed a significative atrophy compared to lean muscles, based on histochemical-stained section's measurements in the sequence: oxidative slow twitch (SO, type I) < oxidative fast twitch (FOG, type IIa) < fast glycolytic (FG, type IIb). Both oxidative fiber's outskirts resembled 'ragged' fibers and, in these zones, ultrastructure revealed small clusters of endoplasm-like reticulum filled with unidentified electron contrasted compounds, contiguous and continuous with adjacent mitochondria envelope. The linings appeared crenated stabbed by circular patterns resembling those found of ceramides. The same fibers contained scattered degraded mitochondria that tethered electron contrasted droplets favoring larger depots while mitoptosis were widespread in FG fibers. Based on other interdisciplinary investigations on the lipid depots of diabetes 2 muscles made us to propose these accumulated contrasted contents to be made of peculiar lipids, including acyl-ceramides, as those were only found while diabetes 2 progresses in aging obese rats. These could interfere in NIDDM with mitochondrial oxidative energetic demands and muscle functions.
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Affiliation(s)
- Jacques Gilloteaux
- Department of Anatomical Sciences, St George's University School of Medicine, K B Taylor Global Scholar's Program at the University of Northumbria, School of Health and Life Sciences, Newcastle upon Tyne, UK.,Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium.,Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA
| | - Charles Nicaise
- Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium
| | - Lindsay Sprimont
- Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium
| | - John Bissler
- Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA.,Division of Nephrology at St. Jude Children's Research Hospital and Le Bonheur Children's Hospital, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Judith A Finkelstein
- Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA
| | - Warren R Payne
- Institute for Sport and Health, Footscray Park Campus, Victoria University, Melbourne, VIC, Australia
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11
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Peng J, Yin L, Wang X. Central and peripheral leptin resistance in obesity and improvements of exercise. Horm Behav 2021; 133:105006. [PMID: 34087669 DOI: 10.1016/j.yhbeh.2021.105006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/25/2021] [Accepted: 05/22/2021] [Indexed: 01/16/2023]
Abstract
Obesity is strongly related to leptin resistance that refers to the state in which leptin fails to inhibit appetite, enhance energy expenditure and regulate glycolipid metabolism, whereas decreasing leptin resistance is important for obesity treatment. Leptin resistance that develops in brain and also directly in peripheral tissues is considered as central and peripheral leptin resistance, respectively. The mechanism of central leptin resistance is the focus of intensive studies but still not totally clarified. A challenged notion about the effect of impaired leptin BBB transport emerges and a concept of "selective leptin resistance" is discussed. Peripheral leptin resistance, especially leptin resistance in muscle, has drawn more attention recently, while its mechanism remains unclear. Exercise is an effective way to reduce obesity, which is at least in part due to the alleviation of leptin resistance. Here, we summarized newly discovered data about the associated factors of central leptin resistance and peripheral leptin resistance, and the actions of exercise on leptin resistance, which is important to understand the mechanisms of leptin resistance and exercise-induced alleviation of leptin resistance, and to facilitate clinical application of leptin in obesity treatment.
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Affiliation(s)
- Jin Peng
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Lijun Yin
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Xiaohui Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China.
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12
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IL-6 family cytokines as potential therapeutic strategies to treat metabolic diseases. Cytokine 2021; 144:155549. [PMID: 33962843 DOI: 10.1016/j.cyto.2021.155549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 02/06/2023]
Abstract
Metabolic disease is highly prevalent. Here we discuss the therapeutic utility of using gp130 receptor ligands as a therapeutic strategy to treat metabolic disease.
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13
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Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
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Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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14
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Fritzen AM, Lundsgaard AM, Kiens B. Tuning fatty acid oxidation in skeletal muscle with dietary fat and exercise. Nat Rev Endocrinol 2020; 16:683-696. [PMID: 32963340 DOI: 10.1038/s41574-020-0405-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/12/2020] [Indexed: 12/31/2022]
Abstract
Both the consumption of a diet rich in fatty acids and exercise training result in similar adaptations in several skeletal muscle proteins. These adaptations are involved in fatty acid uptake and activation within the myocyte, the mitochondrial import of fatty acids and further metabolism of fatty acids by β-oxidation. Fatty acid availability is repeatedly increased postprandially during the day, particularly during high dietary fat intake and also increases during, and after, aerobic exercise. As such, fatty acids are possible signalling candidates that regulate transcription of target genes encoding proteins involved in muscle lipid metabolism. The mechanism of signalling might be direct or indirect targeting of peroxisome proliferator-activated receptors by fatty acid ligands, by fatty acid-induced NAD+-stimulated activation of sirtuin 1 and/or fatty acid-mediated activation of AMP-activated protein kinase. Lactate might also have a role in lipid metabolic adaptations. Obesity is characterized by impairments in fatty acid oxidation capacity, and individuals with obesity show some rigidity in increasing fatty acid oxidation in response to high fat intake. However, individuals with obesity retain improvements in fatty acid oxidation capacity in response to exercise training, thereby highlighting exercise training as a potential method to improve lipid metabolic flexibility in obesity.
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Affiliation(s)
- Andreas Mæchel Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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15
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Eriksson MA, Söderberg S, Nilsson TK, Eriksson M, Boman K, Jansson JH. Leptin levels are not affected by enalapril treatment after an uncomplicated myocardial infarction, but associate strongly with changes in fibrinolytic variables in men. Scandinavian Journal of Clinical and Laboratory Investigation 2020; 80:303-308. [PMID: 32125188 DOI: 10.1080/00365513.2020.1731848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Leptin, an adipocyte-derived hormone, is involved in the regulation of body weight and is associated with obesity-related complications, notably cardiovascular disease (CVD). A putative link between obesity and CVD could be induction of plasminogen activator inhibitor-1 (PAI-1) synthesis by leptin. In this study, we hypothesized that the beneficial effect of the angiotensin-converting enzyme inhibitor (ACEi) enalapril on PAI-1 levels is mediated by effects on leptin levels. The association between leptin and components of the fibrinolytic system was evaluated in a non-prespecified post hoc analysis of a placebo-controlled randomized, double-blind trial where the effect of the ACEi enalapril on fibrinolysis was tested. A total of 46 men and 37 women were randomized to treatment with enalapril or placebo after (median 12 months) an uncomplicated myocardial infarction. At baseline, the participants were stable and had no signs of congestive heart failure. Leptin and fibrinolytic variables (mass concentrations of PAI-1, tissue plasminogen activator (tPA) and tPA-PAI complex) were measured at baseline, and after 10 days, 6 months and 12 months. Enalapril treatment did not change leptin levels, which increased significantly during 1 year of follow-up (p = .007). Changes in leptin levels were strongly associated with changes of tPA mass (p = .001), tPA-PAI complex (p = .003) and of PAI-1 (p = .006) in men, but not in women. Leptin levels are not influenced by treatment with an ACEi. In contrast, leptin associates strongly with changes in fibrinolytic variables notably with a sex difference, which could be of importance for obesity-related CVD.
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Affiliation(s)
- Maria A Eriksson
- Department of Public Health and Clinical Medicine, Medicine, Umeå University, Umea, Sweden
| | - Stefan Söderberg
- Department of Public Health and Clinical Medicine, Medicine, Umeå University, Umea, Sweden
| | - Torbjörn K Nilsson
- Department of Medical Biosciences/Clinical Chemistry, Umeå University, Umea, Sweden
| | - Marie Eriksson
- Department of Statistics, USBE, Umeå University, Umea, Sweden
| | - Kurt Boman
- Research Unit Skellefteå, Department of Public Health and Clinical Medicine, Umeå University, Umea, Sweden
| | - Jan-Håkan Jansson
- Research Unit Skellefteå, Department of Public Health and Clinical Medicine, Umeå University, Umea, Sweden
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16
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Rivadeneira DB, DePeaux K, Wang Y, Kulkarni A, Tabib T, Menk AV, Sampath P, Lafyatis R, Ferris RL, Sarkar SN, Thorne SH, Delgoffe GM. Oncolytic Viruses Engineered to Enforce Leptin Expression Reprogram Tumor-Infiltrating T Cell Metabolism and Promote Tumor Clearance. Immunity 2019; 51:548-560.e4. [PMID: 31471106 DOI: 10.1016/j.immuni.2019.07.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 05/16/2019] [Accepted: 07/12/2019] [Indexed: 02/07/2023]
Abstract
Immunotherapy can reinvigorate dormant responses to cancer, but response rates remain low. Oncolytic viruses, which replicate in cancer cells, induce tumor lysis and immune priming, but their immune consequences are unclear. We profiled the infiltrate of aggressive melanomas induced by oncolytic Vaccinia virus using RNA sequencing and found substantial remodeling of the tumor microenvironment, dominated by effector T cell influx. However, responses to oncolytic viruses were incomplete due to metabolic insufficiencies induced by the tumor microenvironment. We identified the adipokine leptin as a potent metabolic reprogramming agent that supported antitumor responses. Leptin metabolically reprogrammed T cells in vitro, and melanoma cells expressing leptin were immunologically controlled in mice. Engineering oncolytic viruses to express leptin in tumor cells induced complete responses in tumor-bearing mice and supported memory development in the tumor infiltrate. Thus, leptin can provide metabolic support to tumor immunity, and oncolytic viruses represent a platform to deliver metabolic therapy.
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Affiliation(s)
- Dayana B Rivadeneira
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kristin DePeaux
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yiyang Wang
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA; School of Medicine, Tsinghua University, Beijing, China
| | - Aditi Kulkarni
- Head and Neck Cancer SPORE, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tracy Tabib
- Division of Rheumatology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ashley V Menk
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Robert Lafyatis
- Division of Rheumatology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Robert L Ferris
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA; Head and Neck Cancer SPORE, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Stephen H Thorne
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Greg M Delgoffe
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA; Head and Neck Cancer SPORE, University of Pittsburgh, Pittsburgh, PA, USA.
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17
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Kraft EN, Cervone DT, Dyck DJ. Ghrelin stimulates fatty acid oxidation and inhibits lipolysis in isolated muscle from male rats. Physiol Rep 2019; 7:e14028. [PMID: 30963694 PMCID: PMC6453820 DOI: 10.14814/phy2.14028] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 11/24/2022] Open
Abstract
Ghrelin is classically known as a central appetite-stimulating hormone but has recently been recognized to have a significant role in peripheral tissue energy metabolism. However, the direct effects of ghrelin on skeletal muscle, a major site for glucose and lipid disposal, remain understudied. We found that the two major ghrelin isoforms, acylated and unacylated ghrelin, were able to significantly increase skeletal muscle fatty acid oxidation (~20%) while incorporation of fatty acids into major lipid pools remained unchanged. The increase in fatty acid oxidation was accompanied by increases in acetyl-CoA carboxylase phosphorylation, a downstream target of AMPK. Ghrelin isoforms had no independent effect on lipolysis under unstimulated conditions, but nearly completely abolished epinephrine-stimulated lipolysis. This effect was generally, but not consistently related to a blunting in the phosphorylation of HSL activation sites, Ser660 and 563. Taken together, these findings suggest that ghrelin isoforms have a direct, acute effect on fatty acid oxidation and lipolysis.
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Affiliation(s)
- Emily N. Kraft
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Daniel T. Cervone
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - David J. Dyck
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
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18
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Mousa A, Naderpoor N, Mellett N, Wilson K, Plebanski M, Meikle PJ, de Courten B. Lipidomic profiling reveals early-stage metabolic dysfunction in overweight or obese humans. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:335-343. [PMID: 30586632 DOI: 10.1016/j.bbalip.2018.12.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Advances in mass spectrometry and lipidomics techniques are providing new insights into the role of lipid metabolism in obesity-related diseases. However, human lipidomic studies have been inconsistent, owing to the use of indirect proxy measures of metabolic outcomes and relatively limited coverage of the lipidome. Here, we employed comprehensive lipid profiling and gold-standard metabolic measures to test the hypothesis that distinct lipid signatures in obesity may signify early stages of pathogenesis toward type 2 diabetes. METHODS Using high-performance liquid chromatography-electrospray tandem mass spectrometry, we profiled >450 lipid species across 26 classes in 65 overweight or obese non-diabetic individuals. Intensive metabolic testing was conducted using direct gold-standard measures of adiposity (% body fat by dual X-ray absorptiometry), insulin sensitivity (hyperinsulinaemic-euglycaemic clamps), and insulin secretion (intravenous glucose tolerance tests), as well as measurement of serum inflammatory cytokines and adipokines (multiplex assays; flow cytometry). Univariable and multivariable linear regression models were computed using Matlab R2011a, and all analyses were corrected for multiple testing using the Benjamini-Hochberg method. RESULTS We present new evidence showing a strong and independent positive correlation between the lysophosphatidylinositol (LPI) lipid class and insulin secretion in vivo in humans (β [95% CI] = 781.9 [353.3, 1210.4], p = 0.01), supporting the insulinotropic effects of LPI demonstrated in mouse islets. Dihydroceramide, a sphingolipid precursor, was independently and negatively correlated with insulin sensitivity (β [95% CI] = -1.9 [-2.9, -0.9], p = 0.01), indicating a possible upregulation in sphingolipid synthesis in obese individuals. These associations remained significant in multivariable models adjusted for age, sex, and % body fat. The dihexosylceramide class correlated positively with interleukin-10 before and after adjustment for age, sex, and % body fat (p = 0.02), while the phosphatidylethanolamine class and its vinyl ether-linked (plasmalogen) derivatives correlated negatively with % body fat in both univariable and age- and sex-adjusted models (all p < 0.04). CONCLUSIONS Our data suggest that these lipid classes may signify early pathogenesis toward type 2 diabetes and could serve as novel therapeutic targets or biomarkers for diabetes prevention.
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Affiliation(s)
- Aya Mousa
- Monash Centre for Health Research and Implementation (MCHRI), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka Grove, Clayton, VIC 3168, Australia.
| | - Negar Naderpoor
- Monash Centre for Health Research and Implementation (MCHRI), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka Grove, Clayton, VIC 3168, Australia.
| | - Natalie Mellett
- Metabolomics Laboratory, Baker Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.
| | - Kirsty Wilson
- Department of Immunology and Pathology, Monash University, 89 Commercial Road, Melbourne, VIC 3004, Australia.
| | - Magdalena Plebanski
- Department of Immunology and Pathology, Monash University, 89 Commercial Road, Melbourne, VIC 3004, Australia; School of Health and Biomedical Sciences, RMIT University, Corner Janefield Dr and Plenty Road, Bundoora, VIC 3083, Australia.
| | - Peter J Meikle
- Metabolomics Laboratory, Baker Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.
| | - Barbora de Courten
- Monash Centre for Health Research and Implementation (MCHRI), School of Public Health and Preventive Medicine, Monash University, 43-51 Kanooka Grove, Clayton, VIC 3168, Australia.
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19
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Duru K, Kovaleva E, Danilova I, van der Bijl P, Belousova A. The potential beneficial role of isoflavones in type 2 diabetes mellitus. Nutr Res 2018; 59:1-15. [DOI: 10.1016/j.nutres.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/22/2018] [Accepted: 06/24/2018] [Indexed: 01/07/2023]
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20
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Nesrine Z, Haithem H, Imen B, Fadoua N, Asma O, Fadhel NM, Ali B. Leptin and Leptin receptor polymorphisms, plasma Leptin levels and obesity in Tunisian volunteers. Int J Exp Pathol 2018; 99:121-130. [PMID: 29893028 DOI: 10.1111/iep.12271] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 04/14/2018] [Indexed: 12/14/2022] Open
Abstract
Adipose tissue is an important endocrine organ that secretes a number of adipokines, like Leptin (LEP). The aim this study was to investigate the prevalence of single nucleotide polymorphisms in LEP gene (LEP 3'UTR A/C, -2548 G/A) and LEPR (K109R and Q223R) and their association with Leptin level and obesity. We recruited 169 non-obese (body mass index [BMI] = 24.51-3.69 kg/m2 ) and 160 obese (BMI = 36-4.78 kg/m2 ) patients. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism, BMI was calculated, and Leptin level was measured by ELISA. Statistical analyses were performed by spss19.0. According to LEP 3'UTR A/C polymorphism, AC and CC genotype carriers had higher Leptin levels than AA genotype carriers, respectively, 31[0.05-148.8] (P = .008) vs 41[0.05-111.6] (P = .003). The K109R polymorphism was associated with obesity (P = .025) and seems to significantly decrease the LEP levels (P < .001). Concerning LEP G2548A polymorphism, our results showed that the OR of obesity associated with 2548 AA/GG was 1.87[1.106-2.78] P = .028 vs 1.41[1.035-1.85] P = .045 for 223AA/GG polymorphism. In our haplotype analysis, one haplotype seems to be the more protective and one other seems to be the highest risk to obesity. LEP 3'UTR A/C and LEPR K109R polymorphisms were associated with Leptin level and obesity.
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Affiliation(s)
- Zayani Nesrine
- Biochemistry Department, LR12SP11, Sahloul University Hospital, Sousse, Tunisia
| | - Hamdouni Haithem
- Biochemistry Department, LR12SP11, Sahloul University Hospital, Sousse, Tunisia
| | - Boumaiza Imen
- Biochemistry Department, LR12SP11, Sahloul University Hospital, Sousse, Tunisia
| | - Neffati Fadoua
- Laboratory of Biochemistry and Toxicology, Monastir's University Hospital, Monastir, Tunisia
| | - Omezzine Asma
- Biochemistry Department, LR12SP11, Sahloul University Hospital, Sousse, Tunisia
| | - Najjar Mohamed Fadhel
- Laboratory of Biochemistry and Toxicology, Monastir's University Hospital, Monastir, Tunisia
| | - Bouslama Ali
- Biochemistry Department, LR12SP11, Sahloul University Hospital, Sousse, Tunisia
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21
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Perez-Suarez I, Ponce-González JG, de La Calle-Herrero J, Losa-Reyna J, Martin-Rincon M, Morales-Alamo D, Santana A, Holmberg HC, Calbet JAL. Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle. J Appl Physiol (1985) 2017; 123:1276-1287. [DOI: 10.1152/japplphysiol.00454.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/22/2017] [Accepted: 07/19/2017] [Indexed: 11/22/2022] Open
Abstract
In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt−1·day−1) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt−1·day−1). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr1141OBR, phospho-Tyr985OBR, JAK2, and phospho-Tyr1007/1008JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr705STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r = −0.75), phospho-Tyr985OBR ( r = 0.88), and phospho-Tyr705STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles. NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling.
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Affiliation(s)
- Ismael Perez-Suarez
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | | | - Jaime de La Calle-Herrero
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Jose Losa-Reyna
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Marcos Martin-Rincon
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - David Morales-Alamo
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - Alfredo Santana
- Clinical Genetics Unit, Complejo Hospitalario Universitario Insular-Materno Infantil de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Jose A. L. Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
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22
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Engin A. Diet-Induced Obesity and the Mechanism of Leptin Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 960:381-397. [PMID: 28585208 DOI: 10.1007/978-3-319-48382-5_16] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Leptin signaling blockade by chronic overstimulation of the leptin receptor or hypothalamic pro-inflammatory responses due to elevated levels of saturated fatty acid can induce leptin resistance by activating negative feedback pathways. Although, long form leptin receptor (Ob-Rb) initiates leptin signaling through more than seven different signal transduction pathways, excessive suppressor of cytokine signaling-3 (SOCS-3) activity is a potential mechanism for the leptin resistance that characterizes human obesity. Because the leptin-responsive metabolic pathways broadly integrate with other neurons to control energy balance, the methods used to counteract the leptin resistance has extremely limited effect. In this chapter, besides the impairment of central and peripheral leptin signaling pathways, limited access of leptin to central nervous system (CNS) through blood-brain barrier, mismatch between high leptin and the amount of leptin receptor expression, contradictory effects of cellular and circulating molecules on leptin signaling, the connection between leptin signaling and endoplasmic reticulum (ER) stress and self-regulation of leptin signaling has been discussed in terms of leptin resistance.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey.
- , Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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A new leptin-mediated mechanism for stimulating fatty acid oxidation: a pivotal role for sarcolemmal FAT/CD36. Biochem J 2016; 474:149-162. [PMID: 27827305 DOI: 10.1042/bcj20160804] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 10/03/2016] [Accepted: 11/08/2016] [Indexed: 12/15/2022]
Abstract
Leptin stimulates fatty acid oxidation in muscle and heart; but, the mechanism by which these tissues provide additional intracellular fatty acids for their oxidation remains unknown. We examined, in isolated muscle and cardiac myocytes, whether leptin, via AMP-activated protein kinase (AMPK) activation, stimulated fatty acid translocase (FAT/CD36)-mediated fatty acid uptake to enhance fatty acid oxidation. In both mouse skeletal muscle and rat cardiomyocytes, leptin increased fatty acid oxidation, an effect that was blocked when AMPK phosphorylation was inhibited by adenine 9-β-d-arabinofuranoside or Compound C. In wild-type mice, leptin induced the translocation of FAT/CD36 to the plasma membrane and increased fatty acid uptake into giant sarcolemmal vesicles and into cardiomyocytes. In muscles of FAT/CD36-KO mice, and in cardiomyocytes in which cell surface FAT/CD36 action was blocked by sulfo-N-succinimidyl oleate, the leptin-stimulated influx of fatty acids was inhibited; concomitantly, the normal leptin-stimulated increase in fatty acid oxidation was also prevented, despite the normal leptin-induced increase in AMPK phosphorylation. Conversely, in muscle of AMPK kinase-dead mice, leptin failed to induce the translocation of FAT/CD36, along with a failure to stimulate fatty acid uptake and oxidation. Similarly, when siRNA was used to reduce AMPK in HL-1 cardiomyocytes, leptin failed to induce the translocation of FAT/CD36. Our studies have revealed a novel mechanism of leptin-induced fatty acid oxidation in muscle tissue; namely, this process is dependent on the activation of AMPK to induce the translocation of FAT/CD36 to the plasma membrane, thereby stimulating fatty acid uptake. Without increasing this leptin-stimulated, FAT/CD36-dependent fatty acid uptake process, leptin-stimulated AMPK phosphorylation does not enhance fatty acid oxidation.
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Giralt M, Cereijo R, Villarroya F. Adipokines and the Endocrine Role of Adipose Tissues. Handb Exp Pharmacol 2016; 233:265-82. [PMID: 25903415 DOI: 10.1007/164_2015_6] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The last two decades have witnessed a shift in the consideration of white adipose tissue as a mere repository of fat to be used when food becomes scarce to a true endocrine tissue releasing regulatory signals, the so-called adipokines, to the whole body. The control of eating behavior, the peripheral insulin sensitivity, and even the development of the female reproductive system are among the physiological events controlled by adipokines. Recently, the role of brown adipose tissue in human physiology has been recognized. The metabolic role of brown adipose tissue is opposite to white fat; instead of storing fat, brown adipose tissue is a site of energy expenditure via adaptive thermogenesis. There is growing evidence that brown adipose tissue may have its own pattern of secreted hormonal factors, the so-called brown adipokines, having distinctive biological actions on the overall physiological adaptations to enhance energy expenditure.
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Affiliation(s)
- Marta Giralt
- Departament de Bioquímica i Biologia Molecular, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición, Barcelona, Spain
| | - Rubén Cereijo
- Departament de Bioquímica i Biologia Molecular, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición, Barcelona, Spain
| | - Francesc Villarroya
- Departament de Bioquímica i Biologia Molecular, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain. .,CIBER Fisiopatología de la Obesidad y Nutrición, Barcelona, Spain.
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Coles CA. Adipokines in Healthy Skeletal Muscle and Metabolic Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 900:133-60. [DOI: 10.1007/978-3-319-27511-6_6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Coleman SK, Rebalka IA, D’Souza DM, Hawke TJ. Skeletal muscle as a therapeutic target for delaying type 1 diabetic complications. World J Diabetes 2015; 6:1323-1336. [PMID: 26674848 PMCID: PMC4673386 DOI: 10.4239/wjd.v6.i17.1323] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/01/2015] [Accepted: 11/25/2015] [Indexed: 02/05/2023] Open
Abstract
Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease targeting the pancreatic beta-cells and rendering the person hypoinsulinemic and hyperglycemic. Despite exogenous insulin therapy, individuals with T1DM will invariably develop long-term complications such as blindness, kidney failure and cardiovascular disease. Though often overlooked, skeletal muscle is also adversely affected in T1DM, with both physical and metabolic derangements reported. As the largest metabolic organ in the body, impairments to skeletal muscle health in T1DM would impact insulin sensitivity, glucose/lipid disposal and basal metabolic rate and thus affect the ability of persons with T1DM to manage their disease. In this review, we discuss the impact of T1DM on skeletal muscle health with a particular focus on the proposed mechanisms involved. We then identify and discuss established and potential adjuvant therapies which, in association with insulin therapy, would improve the health of skeletal muscle in those with T1DM and thereby improve disease management- ultimately delaying the onset and severity of other long-term diabetic complications.
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Shultz SP, Dahiya R, Leong GM, Rowlands DS, Hills AP, Byrne NM. Muscular strength, aerobic capacity, and adipocytokines in obese youth after resistance training: A pilot study. Australas Med J 2015; 8:113-20. [PMID: 26045721 DOI: 10.4066/amj.2015.2293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Exercise has shown positive training effects on obesity-related inflammation, however, resistance training has shown mixed results concerning adipocytokine levels. AIMS The purpose of this pilot study was to explore the effects of resistance training on blood adipocytokine concentrations in obese youth, with specific examination of the relationship between these biomarkers and improved fitness (i.e., aerobic capacity, muscular strength). METHODS Fourteen obese adolescents (16.1 ±1.6 y; BMI: 32.3 ±3.9 kg/m(2)) participated in a 16-week resistance training intervention. Body composition, fasting blood concentrations of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-ɑ), adiponectin, and leptin were measured pre- and post-training. Aerobic capacity was assessed via a maximal discontinuous exercise test. The rate of gain in muscular strength was calculated as the slope of progression in 1-repetition maximum throughout the intervention. RESULTS Resistance training increased lean mass (total, trunk) and decreased per cent body fat (total, trunk). The training also caused moderate clear decreases in IL-6 and TNF-ɑ concentrations. A small increase in adiponectin was also observed before and after intervention. When the group was stratified by changes in aerobic capacity, there were substantially larger decreases in leptin levels for those with improved capacity. Correlation analyses also revealed a negative relationship between log-transformed leptin and aerobic capacity at rest. Improvement in quadriceps strength was positively correlated with IL-6 and TNF-ɑ, while improvement in shoulder adductor strength was positively correlated with IL-6 only. CONCLUSION Resistance training improved adipocytokine markers, which were partially associated with improved physical fitness. Specifically, the relationship between strength improvements and IL-6 and TNF-ɑ suggests an exercise-induced signalling pathway that results in overall adaptive decreases in systemic inflammation in obese youth.
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Affiliation(s)
- Sarah P Shultz
- School of Sport and Exercise, Massey University, Wellington, New Zealand
| | - Rachana Dahiya
- School of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Gary M Leong
- Department of Paediatric Endocrinology and Diabetes, Mater Children's Hospital, Brisbane, QLD, Australia ; Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia
| | - David S Rowlands
- School of Sport and Exercise, Massey University, Wellington, New Zealand
| | - Andrew P Hills
- Mater Mothers' Hospital & Mater Research Institute, University of Queensland, Brisbane, QLD, Australia
| | - Nuala M Byrne
- Faculty of Health Sciences and Medicine, Bond University, Gold Goast, QLD, Australia
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Kotnik P, Fischer Posovszky P, Wabitsch M. Endocrine and Metabolic Effects of Adipose Tissue in Children and Adolescents. Zdr Varst 2015; 54:131-8. [PMID: 27646920 PMCID: PMC4820166 DOI: 10.1515/sjph-2015-0020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/14/2015] [Indexed: 12/27/2022] Open
Abstract
Adipose tissue is implicated in many endocrine and metabolic processes. Leptin was among the first identified adipose-secreted factors, which act in an auto-, para- and endocrine manner. Since leptin, many other adipose tissue factors were determined, some primarily secreted from the adipocytes, some from other cells of the adipose tissue. So-called adipokines are not only involved in obesity and its complications, as are insulin resistance, type 2 diabetes and other components of the metabolic syndrome, but also in growth, reproduction, bone metabolism, immune response, cancer development and many other important biological processes. Research in the field of adipokines has revealed new insights into the physiological and pathophysiologal processes and opened new therapeutic possibilities. In the present article, a special emphasis is devoted to research in children and adolescents.
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Affiliation(s)
- Primož Kotnik
- University Medical Centre Ljubljana, University Children's Hospital, Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, Bohoriceva 20, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Medicine, Vrazov trg 2, 1000 Ljubljana, Slovenia
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Moon HS, Huh JY, Dincer F, Schneider BE, Hasselgren PO, Mantzoros CS. Identification and saturable nature of signaling pathways induced by metreleptin in humans: comparative evaluation of in vivo, ex vivo, and in vitro administration. Diabetes 2015; 64:828-39. [PMID: 25249580 PMCID: PMC4338590 DOI: 10.2337/db14-0625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Signaling pathways activated by leptin in metabolically important organs have largely been studied only in animal and/or cell culture studies. In this study, we examined whether leptin has similar effects in human peripheral tissues in vivo, ex vivo, and in vitro and whether the response would be different in lean and obese humans. For in vivo leptin signaling, metreleptin was administered and muscle, adipose tissue, and peripheral blood mononuclear cells were taken for analysis of signal activation. Experiments were also done ex vivo and with primary cultured cells in vitro. The signal activation was compared between male versus female and obese versus lean humans. Acute in vivo, ex vivo, and/or in vitro metreleptin administration similarly activated STAT3, AMPK, ERK1/2, Akt, mTOR, NF-κB, and/or IKKα/β without any differences between male versus female and obese versus lean subjects. All signaling pathways were saturable at ∼30-50 ng/mL, consistent with the clinical evidence showing no additional effect(s) in obese subjects who already have high levels of leptin. Our data provide novel information on downstream effectors of metreleptin action in humans that may have therapeutic implications.
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Affiliation(s)
- Hyun-Seuk Moon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Joo Young Huh
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Fadime Dincer
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Benjamin E Schneider
- Division of Minimally Invasive Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Per-Olof Hasselgren
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA
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Chu L, Riddell MC, Schneiderman JE, McCrindle BW, Hamilton JK. The effect of puberty on fat oxidation rates during exercise in overweight and normal-weight girls. J Appl Physiol (1985) 2014; 116:76-82. [DOI: 10.1152/japplphysiol.00888.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Excess weight is often associated with insulin resistance (IR) and may disrupt fat oxidation during exercise. This effect is further modified by puberty. While studies have shown that maximal fat oxidation rates (FOR) during exercise decrease with puberty in normal-weight (NW) and overweight (OW) boys, the effect of puberty in NW and OW girls is unclear. Thirty-three NW and OW girls ages 8–18 yr old completed a peak aerobic capacity test on a cycle ergometer. FOR were calculated during progressive submaximal exercise. Body composition and Tanner stage were determined. For each participant, a best-fit polynomial curve was constructed using fat oxidation vs. exercise intensity to estimate max FOR. In a subset of the girls, IR derived from an oral glucose tolerance test ( n = 20), and leptin and adiponectin levels ( n = 11) were assessed in relation to FOR. NW pre-early pubertal girls had higher max FOR [6.9 ± 1.4 mg·kg fat free mass (FFM)−1·min−1] than NW mid-late pubertal girls (2.2 ± 0.9 mg·kg FFM−1·min−1) ( P = 0.002), OW pre-early pubertal girls (3.8 ± 2.1 mg·kg FFM−1·min−1), and OW mid-late pubertal girls (3.3 ± 0.9 mg·kg FFM−1·min−1) ( P < 0.05). Bivariable analyses showed positive associations between FOR with homeostatic model assessment of IR ( P = 0.001), leptin ( P < 0.001), and leptin-to-adiponectin ratio ( P = 0.001), independent of percent body fat. Max FOR decreased in NW girls during mid-late puberty; however, this decrease associated with puberty was blunted in OW girls due to lower FOR in pre-early puberty. The presence of IR due to obesity potentially masks the effect of puberty on FOR during exercise in girls.
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Affiliation(s)
- L. Chu
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- School of Kinesiology and Health Sciences, Faculty of Health, York University, Toronto, Ontario, Canada
| | - M. C. Riddell
- School of Kinesiology and Health Sciences, Faculty of Health, York University, Toronto, Ontario, Canada
| | - J. E. Schneiderman
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- University of Toronto, Toronto, Ontario, Canada
| | - B. W. McCrindle
- University of Toronto, Toronto, Ontario, Canada
- Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; and
| | - J. K. Hamilton
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Aguirre LE, Jan IZ, Fowler K, Waters DL, Villareal DT, Armamento-Villareal R. Testosterone and Adipokines are Determinants of Physical Performance, Strength, and Aerobic Fitness in Frail, Obese, Older Adults. Int J Endocrinol 2014; 2014:507395. [PMID: 25165472 PMCID: PMC4140116 DOI: 10.1155/2014/507395] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/04/2014] [Indexed: 01/11/2023] Open
Abstract
In this study, we evaluated the independent and combined effects of baseline circulating gonadal, anabolic hormones and adipokines on physical function in 107 frail, obese (BMI ≥ 30 kg/m(2)), and older (≥65 yr) subjects. Our results showed significant positive correlations between circulating testosterone and insulin growth factor-1 (IGF-1) with knee flexion, knee extension, one-repetition maximum (1-RM), and peak oxygen consumption (VO2 peak), while no correlation was observed with estradiol. Among the adipokines, high sensitivity C-reactive protein (Hs-CRP) and leptin negatively correlated with the modified physical performance testing (PPT), knee flexion, knee extension, 1-RM, and VO2 peak. Interleukin-6 ( Il-6) negatively correlated with knee flexion and VO2 peak and soluble tumor necrosis factors receptor-1 (sTNFr1) correlated with PPT, 1-RM, and VO2 peak. Adiponectin correlated negatively with 1-RM. Multiple regression analysis revealed that, for PPT, sTNFr1 was the only independent predictor. Independent predictors included adiponectin, leptin, and testosterone for knee flexion; leptin and testosterone for knee extension; adiponectin, leptin, and testosterone for 1-RM; and IGF-1, IL-6, leptin, and testosterone for VO2 peak. In conclusion, in frail obese older adults, circulating levels of testosterone, adiponectin, and leptin appear to be important predictors of physical strength and fitness, while inflammation appears to be a major determinant of physical frailty.
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Affiliation(s)
- Lina E. Aguirre
- New Mexico VA Health Care System, 1501 San Pedro SE, Albuquerque, NM 87108, USA
- Biomedical Research Institute of New Mexico, Albuquerque, NM 87108, USA
- *Lina E. Aguirre:
| | - Irum Zeb Jan
- New Mexico VA Health Care System, 1501 San Pedro SE, Albuquerque, NM 87108, USA
| | - Kenneth Fowler
- New Mexico VA Health Care System, 1501 San Pedro SE, Albuquerque, NM 87108, USA
- Biomedical Research Institute of New Mexico, Albuquerque, NM 87108, USA
| | - Debra L. Waters
- University of Otago, Dunedin 9016, New Zealand
- University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Dennis T. Villareal
- New Mexico VA Health Care System, 1501 San Pedro SE, Albuquerque, NM 87108, USA
- University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Reina Armamento-Villareal
- New Mexico VA Health Care System, 1501 San Pedro SE, Albuquerque, NM 87108, USA
- University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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32
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Guerra B, Ponce-González JG, Morales-Alamo D, Guadalupe-Grau A, Kiilerich K, Fuentes T, Ringholm S, Biensø RS, Santana A, Lundby C, Pilegaard H, Calbet JAL. Leptin signaling in skeletal muscle after bed rest in healthy humans. Eur J Appl Physiol 2013; 114:345-57. [PMID: 24292882 DOI: 10.1007/s00421-013-2779-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 11/18/2013] [Indexed: 12/22/2022]
Abstract
PURPOSE This study aimed at determining the effects of bed rest on the skeletal muscle leptin signaling system. METHODS Deltoid and vastus lateralis muscle biopsies and blood samples were obtained from 12 healthy young men (mean ± SD, BMI 22.8 ± 2.7 kg/m(2)) before and after 7 days of bed rest. Leptin receptor isoforms (OB-Rs), suppressor of cytokine signaling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) protein expression and signal transducer and activator of transcription 3 (STAT3) phosphorylation were analyzed by Western blot. RESULTS After bed rest basal insulin concentration was increased by 53% (P < 0.05), the homeostasis model assessment (HOMA) by 40% (P < 0.05), and serum leptin concentration by 35% (P < 0.05) with no changes in body fat mass. Although the soluble isoform of the leptin receptor (s-OBR) remained unchanged, the molar excess of leptin over sOB-R was increased by 1.4-fold after bed rest (P < 0.05). OB-Rs and SOCS3 protein expression, and STAT3 phosphorylation level remained unaffected in deltoid and vastus lateralis by bed rest, as PTP1B in the deltoid. PTP1B was increased by 90% with bed rest in the vastus lateralis (P < 0.05). There was a linear relationship between the increase in vastus lateralis PTP1B and the increase in both basal insulin concentrations (r = 0.66, P < 0.05) and HOMA (r = 0.68, P < 0.05) with bed rest. CONCLUSIONS One week of bed rest is associated with increased leptin levels without augmenting STAT3 phosphorylation indicating some degree of leptin resistance in skeletal muscle, which can be explained, at least in part, by an elevation of PTP1B protein content in the vastus lateralis muscle.
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Affiliation(s)
- Borja Guerra
- Departamento de Educación Física, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017, Las Palmas de Gran Canaria, Canary Island, Spain,
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Roberts CK, Hevener AL, Barnard RJ. Metabolic syndrome and insulin resistance: underlying causes and modification by exercise training. Compr Physiol 2013; 3:1-58. [PMID: 23720280 DOI: 10.1002/cphy.c110062] [Citation(s) in RCA: 270] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Metabolic syndrome (MS) is a collection of cardiometabolic risk factors that includes obesity, insulin resistance, hypertension, and dyslipidemia. Although there has been significant debate regarding the criteria and concept of the syndrome, this clustering of risk factors is unequivocally linked to an increased risk of developing type 2 diabetes and cardiovascular disease. Regardless of the true definition, based on current population estimates, nearly 100 million have MS. It is often characterized by insulin resistance, which some have suggested is a major underpinning link between physical inactivity and MS. The purpose of this review is to: (i) provide an overview of the history, causes and clinical aspects of MS, (ii) review the molecular mechanisms of insulin action and the causes of insulin resistance, and (iii) discuss the epidemiological and intervention data on the effects of exercise on MS and insulin sensitivity.
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Affiliation(s)
- Christian K Roberts
- Exercise and Metabolic Disease Research Laboratory, Translational Sciences Section, School of Nursing, University of California at Los Angeles, Los Angeles, California, USA.
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Antony B, Jones G, Stannus O, Blizzard L, Ding C. Body fat predicts an increase and limb muscle strength predicts a decrease in leptin in older adults over 2·6 years. Clin Endocrinol (Oxf) 2013; 79:652-60. [PMID: 23146120 DOI: 10.1111/cen.12101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 11/07/2012] [Accepted: 11/07/2012] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Obesity is characterized by hyperleptinaemia, which is associated with diabetes, hypertension and coronary heart disease. The aim of this study was to determine if body fat and muscle measures predict the natural increase in leptin over 2·6 years in older adults. METHODS A total of 190 subjects (50% females) aged between 50 and 79 years were selected to perform the serum measurements for leptin. Height and weight were measured and body mass index (BMI) was calculated. Fat and lean mass of the whole body and the trunk were acquired through dual-energy X-ray absorptiometry (DXA). Leg muscle strength and handgrip strength were measured using dynamometry. RESULTS In multivariable analyses, leg muscle strength was negatively associated with both baseline leptin (β: -0·05 μg/l per kg, 95% CI: -0·08, -0·02) and follow-up leptin (β: -0·04 μg/l per kg, 95% CI: -0·07, -0·01). BMI, and percentage total fat and trunk fat and their respective change per annum (cpa) were significantly and positively associated with leptin. Lean mass was negatively associated with baseline leptin. Gender-specific analyses produced similar associations between leg muscle strength, fat measures and follow-up leptin in males and females. CONCLUSION Besides positive associations between body fat, trunk fat and leptin, we found that leg muscle strength was negatively associated with leptin after 2·6 years in a sample of older population. This suggests that interventions to maintain or increase muscle strength may have a protective effect on hyperleptinaemia.
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Affiliation(s)
- Benny Antony
- Menzies Research Institute, University of Tasmania, Hobart, Australia
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35
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Palacios-González B, Zarain-Herzberg A, Flores-Galicia I, Noriega LG, Alemán-Escondrillas G, Zariñan T, Ulloa-Aguirre A, Torres N, Tovar AR. Genistein stimulates fatty acid oxidation in a leptin receptor-independent manner through the JAK2-mediated phosphorylation and activation of AMPK in skeletal muscle. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:132-40. [PMID: 24013029 DOI: 10.1016/j.bbalip.2013.08.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 08/02/2013] [Accepted: 08/27/2013] [Indexed: 11/19/2022]
Abstract
Obesity is a public health problem that contributes to the development of insulin resistance, which is associated with an excessive accumulation of lipids in skeletal muscle tissue. There is evidence that soy protein can decrease the ectopic accumulation of lipids and improves insulin sensitivity; however, it is unknown whether soy isoflavones, particularly genistein, can stimulate fatty acid oxidation in the skeletal muscle. Thus, we studied the mechanism by which genistein stimulates fatty acid oxidation in the skeletal muscle. We showed that genistein induced the expression of genes of fatty acid oxidation in the skeletal muscle of Zucker fa/fa rats and in leptin receptor (ObR)-silenced C2C12 myotubes through AMPK phosphorylation. Furthermore, the genistein-mediated AMPK phosphorylation occurred via JAK2, which was possibly activated through a mechanism that involved cAMP. Additionally, the genistein-mediated induction of fatty acid oxidation genes involved PGC1α and PPARδ. As a result, we observed that genistein increased fatty acid oxidation in both the control and silenced C2C12 myotubes, as well as a decrease in the RER in mice, suggesting that genistein can be used in strategies to decrease lipid accumulation in the skeletal muscle.
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Affiliation(s)
- Berenice Palacios-González
- Posgrado Ciencias Bioquímicas, Facultad de Química, UNAM, México, D.F. 04510, Mexico; Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F. 14000, Mexico
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Allison MA, Bluemke DA, McClelland R, Cushman M, Criqui MH, Polak JF, Lima JA. Relation of leptin to left ventricular hypertrophy (from the Multi-Ethnic Study of Atherosclerosis). Am J Cardiol 2013; 112:726-30. [PMID: 23711806 PMCID: PMC3745795 DOI: 10.1016/j.amjcard.2013.04.053] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 01/21/2023]
Abstract
Increasing adiposity increases the risk for left ventricular (LV) hypertrophy. Adipokines are hormone-like substances from adipose tissue that influence several metabolic pathways relevant to LV hypertrophy. Data were obtained from participants enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA) who underwent magnetic resonance imaging of the heart and who also had fasting venous blood assayed for 4 distinct adipokines (adiponectin, leptin, tumor necrosis factor-α, and resistin). One-thousand four hundred sixty four MESA participants had complete data. The mean age was 61.5 years, the mean body mass index was 27.6 kg/m², and 49% were women. With adjustment for age, gender, race, height, and weight, multivariate linear regression modeling revealed that a 1-SD increment in leptin was significantly associated with smaller LV mass (ß: -4.66% predicted, p <0.01), LV volume (-5.87% predicted, p <0.01), stroke volume (-3.23 ml, p <0.01), and cardiac output (-120 ml/min, p = 0.01) as well as a lower odds ratio for the presence of LV hypertrophy (odds ratio 0.65, p <0.01), but a higher ejection fraction (0.44%, p = 0.05). Additional adjustment for the traditional cardiovascular disease risk factors, insulin resistance, physical activity, education, income, inflammatory biomarkers, other selected adipokines, and pericardial fat did not materially change the magnitude or significance of the associations. The associations between the other adipokines and LV structure and function were inconsistent and largely nonsignificant. In conclusion, the results indicate that higher levels of leptin are associated with more favorable values of several measures of LV structure and function.
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Affiliation(s)
- Matthew A Allison
- Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA, USA.
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Cahill F, Amini P, Wadden D, Khalili S, Randell E, Vasdev S, Gulliver W, Sun G. Short-term overfeeding increases circulating adiponectin independent of obesity status. PLoS One 2013; 8:e74215. [PMID: 24023698 PMCID: PMC3758269 DOI: 10.1371/journal.pone.0074215] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/29/2013] [Indexed: 12/22/2022] Open
Abstract
Background Adiponectin is an adipose tissue derived hormone which strengthens insulin sensitivity. However, there is little data available regarding the influence of a positive energy challenge (PEC) on circulating adiponectin and the role of obesity status on this response. Objective The purpose of this study was to investigate how circulating adiponectin will respond to a short-term PEC and whether or not this response will differ among normal-weight(NW), overweight(OW) and obese(OB). Design We examined adiponectin among 64 young men (19-29 yr) before and after a 7-day overfeeding (70% above normal energy requirements). The relationship between adiponectin and obesity related phenotypes including; weight, percent body fat (%BF), percent trunk fat (%TF), percent android fat (%AF), body mass index (BMI), total cholesterol, HDLc, LDLc, glucose, insulin, homeostatic model assessment insulin resistance (HOMA-IR) and β-cell function (HOMA-β) were analyzed before and after overfeeding. Results Analysis of variance (ANOVA) and partial correlations were used to compute the effect of overfeeding on adiponectin and its association with adiposity measurements, respectively. Circulating Adiponectin levels significantly increased after the 7-day overfeeding in all three adiposity groups. Moreover, adiponectin at baseline was not significantly different among NW, OW and OB subjects defined by either %BF or BMI. Baseline adiponectin was negatively correlated with weight and BMI for the entire cohort and %TF, glucose, insulin and HOMA-IR in OB. However, after controlling for insulin resistance the correlation of adiponectin with weight, BMI and %TF were nullified. Conclusion Our study provides evidence that the protective response of adiponectin is preserved during a PEC regardless of adiposity. Baseline adiponectin level is not directly associated with obesity status and weight gain in response to short-term overfeeding. However, the significant increase of adiponectin in response to overfeeding indicates the physiological potential for adiponectin to attenuate insulin resistance during the development of obesity.
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Affiliation(s)
- Farrell Cahill
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Peyvand Amini
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Danny Wadden
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Sammy Khalili
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Edward Randell
- Discipline of Laboratory Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Sudesh Vasdev
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Wayne Gulliver
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Guang Sun
- Division of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada
- * E-mail:
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Trajcevski KE, O’Neill HM, Wang DC, Thomas MM, Al-Sajee D, Steinberg GR, Ceddia RB, Hawke TJ. Enhanced lipid oxidation and maintenance of muscle insulin sensitivity despite glucose intolerance in a diet-induced obesity mouse model. PLoS One 2013; 8:e71747. [PMID: 23951235 PMCID: PMC3741110 DOI: 10.1371/journal.pone.0071747] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/03/2013] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Diet-induced obesity is a rising health concern which can lead to the development of glucose intolerance and muscle insulin resistance and, ultimately, type II diabetes mellitus. This research investigates the associations between glucose intolerance or muscle insulin resistance and tissue specific changes during the progression of diet-induced obesity. METHODOLOGY C57BL/6J mice were fed a normal or high-fat diet (HFD; 60% kcal fat) for 3 or 8 weeks. Disease progression was monitored by measurements of body/tissue mass changes, glucose and insulin tolerance tests, and ex vivo glucose uptake in intact muscles. Lipid metabolism was analyzed using metabolic chambers and ex vivo palmitate assays in intact muscles. Skeletal muscle, liver and adipose tissues were analyzed for changes in inflammatory gene expression. Plasma was analyzed for insulin levels and inflammatory proteins. Histological techniques were used on muscle and liver cryosections to assess metabolic and morphological changes. PRINCIPAL FINDINGS/CONCLUSIONS A rapid shift in whole body metabolism towards lipids was observed with HFD. Following 3 weeks of HFD, elevated total lipid oxidation and an oxidative fiber type shift had occurred in the skeletal muscle, which we propose was responsible for delaying intramyocellular lipid accumulation and maintaining muscle's insulin sensitivity. Glucose intolerance was present after three weeks of HFD and was associated with an enlarged adipose tissue depot, adipose tissue inflammation and excess hepatic lipids, but not hepatic inflammation. Furthermore, HFD did not significantly increase systemic or muscle inflammation after 3 or 8 weeks of HFD suggesting that early diet-induced obesity does not cause inflammation throughout the whole body. Overall these findings indicate skeletal muscle did not contribute to the development of HFD-induced impairments in whole-body glucose tolerance following 3 weeks of HFD.
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Affiliation(s)
- Karin E. Trajcevski
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Hayley M. O’Neill
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - David C. Wang
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Melissa M. Thomas
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Dhuha Al-Sajee
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | - Rolando B. Ceddia
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Thomas J. Hawke
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
- * E-mail:
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Feng H, Zheng L, Feng Z, Zhao Y, Zhang N. The role of leptin in obesity and the potential for leptin replacement therapy. Endocrine 2013; 44:33-9. [PMID: 23274948 DOI: 10.1007/s12020-012-9865-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 12/15/2012] [Indexed: 12/13/2022]
Abstract
Leptin (from the Greek word "lepto'' meaning "thin") is a 167-amino acid peptide hormone encoded by the obesity (ob) gene and secreted by white adipocytes. Blood leptin concentrations are increased in obese individuals. Leptin is a satiety hormone that provides negative feedback to the hypothalamus, controlling appetite and energy expenditure. Leptin binds to presynaptic GABAergic neurons to produce its effect, raising the distinct possibility that GABAergic axon terminals are the ultimate subcellular site of action for its effects. Released into the circulation, leptin crosses the blood-brain barrier and binds to leptin receptors, influencing the activity of various hypothalamic neurons, as well as encoding orexigenic and anorexigenic neuropeptides. Moreover, leptin affects a wide range of metabolic functions in the peripheral tissue. In this review, we discuss some physiologic functions of leptin, including effects on obesity and some effects of leptin replacement therapy.
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Affiliation(s)
- Helin Feng
- Department of Orthopedics, The Fourth Affiliated Hospital of Hebei Medical University, 12 Health Road, Shijiazhuang, 050011, China.
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Thrush AB, Dent R, McPherson R, Harper ME. Implications of mitochondrial uncoupling in skeletal muscle in the development and treatment of obesity. FEBS J 2013; 280:5015-29. [DOI: 10.1111/febs.12399] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/03/2013] [Accepted: 06/17/2013] [Indexed: 12/13/2022]
Affiliation(s)
- A. Brianne Thrush
- Department of Biochemistry, Microbiology and Immunology; Faculty of Medicine; University of Ottawa; Ontario; Canada
| | - Robert Dent
- Ottawa Hospital Weight Management Clinic; Ottawa Hospital; Ontario; Canada
| | | | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology; Faculty of Medicine; University of Ottawa; Ontario; Canada
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Bucci L, Yani SL, Fabbri C, Bijlsma AY, Maier AB, Meskers CG, Narici MV, Jones DA, McPhee JS, Seppet E, Gapeyeva H, Pääsuke M, Sipilä S, Kovanen V, Stenroth L, Musarò A, Hogrel JY, Barnouin Y, Butler-Browne G, Capri M, Franceschi C, Salvioli S. Circulating levels of adipokines and IGF-1 are associated with skeletal muscle strength of young and old healthy subjects. Biogerontology 2013; 14:261-72. [PMID: 23666343 DOI: 10.1007/s10522-013-9428-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/29/2013] [Indexed: 01/20/2023]
Abstract
It is known that adipose tissue mass increases with age, and that a number of hormones, collectively called adipokines, are produced by adipose tissue. For most of them it is not known whether their plasmatic levels change with age. Moreover, it is known that adipose tissue infiltration in skeletal muscle is related to sarcopenia and loss of muscle strength. In this study we investigated the age-related changes of representative adipokines and insulin-like growth factor (IGF)-1 and their effect on muscle strength. We studied the association between circulating levels of adiponectin, leptin, resistin and IGF-1 and muscle strength. This cross-sectional study included 412 subjects of different age (152 subjects aged 18-30 years and 260 subjects aged 69-81 years) recruited within the framework of the European research network project "Myoage". The levels of adiponectin (both in male and female subjects) and leptin (only in males) were significantly higher in old subjects compared to young, while those of IGF-1 were lower in old subjects. In old subjects adiponectin, resistin and the resistin/IGF-1 ratio (but not IGF-1 alone) were inversely associated with quadriceps torque, while only adiponectin was inversely associated with handgrip strength independently from percentage of fat mass, height, age, gender and geographical origin. The ratio of leptin to adiponectin was directly associated with handgrip strength in both young and old subjects. These results suggest that in humans the age-associated loss of strength is associated with the levels of representative adipokines and IGF-1.
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Affiliation(s)
- Laura Bucci
- Department of Experimental, Diagnostic and Specialty Medicine and CIG-Interdepartmental Centre L. Galvani, University of Bologna, via S. Giacomo 12, 40126, Bologna, Italy
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Jonkers RAM, van Loon LJC, Nicolay K, Prompers JJ. In vivo postprandial lipid partitioning in liver and skeletal muscle in prediabetic and diabetic rats. Diabetologia 2013; 56:618-26. [PMID: 23238787 PMCID: PMC3563947 DOI: 10.1007/s00125-012-2792-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/12/2012] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Insulin resistance and type 2 diabetes have been associated with ectopic lipid deposition. This study investigates the derangements in postprandial lipid handling in liver and skeletal muscle tissue at different stages during the pathogenesis of type 2 diabetes in a rat model. METHODS Four groups (n = 6) of male Zucker diabetic fatty rats were used for this study: prediabetic fa/fa rats and healthy fa/+ littermates at the age of 6 weeks, and diabetic fa/fa rats and healthy fa/+ littermates at the age of 12 weeks. In vivo (1)H-[(13)C] magnetic resonance spectroscopy measurements were performed in liver and tibialis anterior muscle at baseline and 4, 24 and 48 h after oral administration of 1.5 g [U-(13)C]algal lipid mixture per kilogram body weight. Total and (13)C-labelled intracellular lipid contents were determined from the magnetic resonance spectra. RESULTS In both prediabetic and diabetic rats, total lipid contents in muscle and liver were substantially higher than in healthy controls and this was accompanied by a 2.3-fold greater postprandial lipid uptake in the liver (p < 0.001). Interestingly, in prediabetic rats, skeletal muscle appeared to be protected from excess lipid uptake whereas after developing overt diabetes muscle lipid uptake was 3.4-fold higher than in controls (p < 0.05). Muscle lipid use was significantly lower in prediabetic and diabetic muscle, indicative of impairments in lipid oxidation. CONCLUSIONS/INTERPRETATION In vivo postprandial lipid handling is disturbed in both liver and skeletal muscle tissue in prediabetic and diabetic rats, but the uptake of dietary lipids in muscle is only increased after the development of overt diabetes.
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Affiliation(s)
- R. A. M. Jonkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the Netherlands
| | - L. J. C. van Loon
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Movement Sciences, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - K. Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the Netherlands
| | - J. J. Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the Netherlands
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Jorgensen SB, O'Neill HM, Sylow L, Honeyman J, Hewitt KA, Palanivel R, Fullerton MD, Öberg L, Balendran A, Galic S, van der Poel C, Trounce IA, Lynch GS, Schertzer JD, Steinberg GR. Deletion of skeletal muscle SOCS3 prevents insulin resistance in obesity. Diabetes 2013; 62:56-64. [PMID: 22961088 PMCID: PMC3526029 DOI: 10.2337/db12-0443] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Obesity is associated with chronic low-grade inflammation that contributes to defects in energy metabolism and insulin resistance. Suppressor of cytokine signaling (SOCS)-3 expression is increased in skeletal muscle of obese humans. SOCS3 inhibits leptin signaling in the hypothalamus and insulin signal transduction in adipose tissue and the liver. Skeletal muscle is an important tissue for controlling energy expenditure and whole-body insulin sensitivity; however, the physiological importance of SOCS3 in this tissue has not been examined. Therefore, we generated mice that had SOCS3 specifically deleted in skeletal muscle (SOCS MKO). The SOCS3 MKO mice had normal muscle development, body mass, adiposity, appetite, and energy expenditure compared with wild-type (WT) littermates. Despite similar degrees of obesity when fed a high-fat diet, SOCS3 MKO mice were protected against the development of hyperinsulinemia and insulin resistance because of enhanced skeletal muscle insulin receptor substrate 1 (IRS1) and Akt phosphorylation that resulted in increased skeletal muscle glucose uptake. These data indicate that skeletal muscle SOCS3 does not play a critical role in regulating muscle development or energy expenditure, but it is an important contributing factor for inhibiting insulin sensitivity in obesity. Therapies aimed at inhibiting SOCS3 in skeletal muscle may be effective in reversing obesity-related glucose intolerance and insulin resistance.
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Affiliation(s)
- Sebastian Beck Jorgensen
- St. Vincent’s Institute of Medical Research and Department of Medicine, University of Melbourne, Fitzroy, Victoria, Australia.
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Yang Z, Hulver M, McMillan RP, Cai L, Kershaw EE, Yu L, Xue B, Shi H. Regulation of insulin and leptin signaling by muscle suppressor of cytokine signaling 3 (SOCS3). PLoS One 2012; 7:e47493. [PMID: 23115649 PMCID: PMC3480378 DOI: 10.1371/journal.pone.0047493] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 09/17/2012] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle resistance to the key metabolic hormones, leptin and insulin, is an early defect in obesity. Suppressor of cytokine signaling 3 (SOCS3) is a major negative regulator of both leptin and insulin signaling, thereby implicating SOCS3 in the pathogenesis of obesity and associated metabolic abnormalities. Here, we demonstrate that SOCS3 mRNA expression is increased in murine skeletal muscle in the setting of diet-induced and genetic obesity, inflammation, and hyperlipidemia. To further evaluate the contribution of muscle SOCS3 to leptin and insulin resistance in obesity, we generated transgenic mice with muscle-specific overexpression of SOCS3 (MCK/SOCS3 mice). Despite similar body weight, MCK/SOCS3 mice develop impaired systemic and muscle-specific glucose homeostasis and insulin action based on glucose and insulin tolerance tests, hyperinsulinemic-euglycemic clamps, and insulin signaling studies. With regards to leptin action, MCK/SOCS3 mice exhibit suppressed basal and leptin-stimulated activity and phosphorylation of alpha2 AMP-activated protein kinase (α2AMPK) and its downstream target, acetyl-CoA carboxylase (ACC). Muscle SOCS3 overexpression also suppresses leptin-regulated genes involved in fatty acid oxidation and mitochondrial function. These studies demonstrate that SOC3 within skeletal muscle is a critical regulator of leptin and insulin action and that increased SOCS may mediate insulin and leptin resistance in obesity.
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Affiliation(s)
- Zhenggang Yang
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- State Key Laboratory of Infectious Disease Diagnosis and Treatment, First Affiliated Hospital of Zhejiang University, Hang Zhou, China
| | - Matthew Hulver
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Ryan P. McMillan
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Lingzhi Cai
- Division of Endocrinology, Diabetes, and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Erin E. Kershaw
- Division of Endocrinology, Diabetes, and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Liqing Yu
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Bingzhong Xue
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Hang Shi
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
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El Akoum S, Cloutier I, Tanguay JF. Vascular smooth muscle cell alterations triggered by mice adipocytes: role of high-fat diet. J Atheroscler Thromb 2012; 19:1128-41. [PMID: 23047600 DOI: 10.5551/jat.13482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM Inherent mechanisms leading to vascular smooth muscle cells (VSMC) alterations in obesitylinked type 2 diabetes (T2D) situation remain to be clarified. This study evaluates the impact of supernatant of adipocytes extracted from mice fed high-fat-diets (HFD) on the proliferation and apoptosis of VSMC. METHODS Adipocytes were extracted from visceral white fat pads of male and female C57Bl6 mice showing different stages of metabolic alterations after 20 weeks of vegetal or animal HFD feeding. These cells were stimulated or not with insulin or glucose to condition VSMC media. After 24h of stimulation with adipocyte supernatants (AdS), VSMC proliferation and sustainability were assessed in the absence and presence of AdS. CD36 and insulin receptor mRNA levels were also evaluated. RESULTS Proliferation and viability of VSMC were significantly modulated by the nature of the AdS used and the gender of mice from which adipocytes have been extracted. The most extensive effects on VSMC were triggered by adipocytes from males fed animal HFD and females fed vegetal HFD. These effects were concurrent with increased leptin concentration and decreased adiponectin levels in AdS. In addition, adipocytes of HFD-fed mice increased caspase-3 activity and apoptosis in VSMC. Significant up-regulation of CD36 mRNA was also found in these cells. CONCLUSION Adipocytes of HFD-fed mice induce VSMC alterations. These changes involved mouse gender, most probably correlated to the diet-induced adipocyte secretion profile. Greater sensitivity to AdS effects in VSMC raises concerns about the more frequent cardiovascular events associated with obesity in the presence of T2D, which impairs adipocyte activity.
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Harwood HJ. The adipocyte as an endocrine organ in the regulation of metabolic homeostasis. Neuropharmacology 2012; 63:57-75. [DOI: 10.1016/j.neuropharm.2011.12.010] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/28/2011] [Accepted: 12/09/2011] [Indexed: 02/06/2023]
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Tan B, Li X, Yin Y, Wu Z, Liu C, Tekwe CD, Wu G. Regulatory roles for L-arginine in reducing white adipose tissue. FRONT BIOSCI-LANDMRK 2012; 17:2237-46. [PMID: 22652774 PMCID: PMC3422877 DOI: 10.2741/4047] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As the nitrogenous precursor of nitric oxide, L-arginine regulates multiple metabolic pathways involved in the metabolism of fatty acids, glucose, amino acids, and proteins through cell signaling and gene expression. Specifically, arginine stimulates lipolysis and the expression of key genes responsible for activation of fatty acid oxidation to CO2 and water. The underlying mechanisms involve increases in the expression of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha), mitochondrial biogenesis, and the growth of brown adipose tissue growth. Furthermore, arginine regulates adipocyte-muscle crosstalk and energy partitioning via the secretion of cytokines and hormones. In addition, arginine enhances AMP-activated protein kinase (AMPK) expression and activity, thereby modulating lipid metabolism and energy balance toward the loss of triacylglycerols. Growing evidence shows that dietary supplementation with arginine effectively reduces white adipose tissue in Zucker diabetic fatty rats, diet-induced obese rats, growing-finishing pigs, and obese patients with type II diabetes. Thus, arginine can be used to prevent and treat adiposity and the associated metabolic syndrome.
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Affiliation(s)
- Bi’e Tan
- Research Center of Healthy Breeding of Livestock and Poultry and Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha, Hunan, China 410125
| | - Xinguo Li
- Hunan Institute of Animal Husbandry and Veterinary Medicine, Changsha, Hunan, China 410131
| | - Yulong Yin
- Research Center of Healthy Breeding of Livestock and Poultry and Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha, Hunan, China 410125
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China 100193
| | - Chuang Liu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China 100193
| | - Carmen D. Tekwe
- Department of Statistics, Texas A and M University, College Station, TX, USA 77843-3143
| | - Guoyao Wu
- Research Center of Healthy Breeding of Livestock and Poultry and Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha, Hunan, China 410125
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China 100193
- Department of Animal Science, Texas A&M University, College Station, TX, USA 77843-2471
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Tishinsky JM, Gulli RA, Mullen KL, Dyck DJ, Robinson LE. Fish oil prevents high-saturated fat diet-induced impairments in adiponectin and insulin response in rodent soleus muscle. Am J Physiol Regul Integr Comp Physiol 2012; 302:R598-605. [DOI: 10.1152/ajpregu.00328.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High saturated fatty acid (SFA) diets contribute to the development of insulin resistance, whereas fish oil-derived n-3 polyunsaturated fatty acids (PUFA) increase the secretion of adiponectin (Ad), an adipocyte-derived protein that stimulates fatty acid oxidation (FAO) and improves skeletal muscle insulin response. We sought to determine whether fish oil could prevent and/or restore high SFA diet-induced impairments in Ad and insulin response in soleus muscle. Sprague-Dawley rats were fed 1) a low-fat control diet (CON group), 2) high-SFA diet (SFA group), or 3) high SFA with n-3 PUFA diet (SFA/n-3 PUFA group). At 4 wk, CON and SFA/n-3 PUFA animals were terminated, and SFA animals were either terminated or fed SFA or SFA/n-3 PUFA for an additional 2 or 4 wk. The effect of diet on Ad-stimulated FAO, insulin-stimulated glucose transport, and expression of Ad, insulin and inflammatory signaling proteins was determined in the soleus muscle. Ad stimulated FAO in CON and 4 wk SFA/n-3 PUFA (+36%, +39%, respectively P ≤ 0.05) only. Insulin increased glucose transport in CON, 4 wk SFA/n-3 PUFA, and 4 wk SFA + 4 wk SFA/n-3 PUFA (+82%, +33%, +25%, respectively P ≤ 0.05); this effect was lost in all other groups. TLR4 expression was increased with 4 wk of SFA feeding (+24%, P ≤ 0.05), and this was prevented in 4 wk SFA/n-3 PUFA. Suppressor of cytokine signaling-3 expression was increased in SFA and SFA/n-3 PUFA (+33 and +18%, respectively, P ≤ 0.05). Our results demonstrate that fish oil can prevent high SFA diet-induced impairments in both Ad and insulin response in soleus muscle.
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Affiliation(s)
- Justine M. Tishinsky
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Roberto A. Gulli
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Kerry L. Mullen
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Lindsay E. Robinson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Saafi MA, Frere-Meunier D, Feasson L, Boutahar N, Denis C. Physical fitness is independently related to blood leptin concentration and insulin sensitivity index in male subjects with central adiposity. Obes Facts 2012; 5:91-103. [PMID: 22433621 DOI: 10.1159/000336077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 08/28/2011] [Indexed: 12/13/2022] Open
Abstract
AIM To compare the maximal power output (MPO) of subjects presenting a central adiposity to those of controls and to study the links between plasma leptin or indices of insulin sensitivity (QUICKI) and physical fitness (PF). METHODS MPO was determined for 169 middle-aged men divided into two groups according to waist circumference (WC- < 94 cm, WC+ ≥ 94 cm) each subdivided in two subgroups with low and high PF (WC-L, WC-H, WC+L, WC+H) determined from the median MPO relative to fat free mass (3.06 W/kg(FFM)). RESULTS MPO (W/kg(FFM)) was lower in WC+ than in WC-. Expressed relative to fat mass, leptin was lower and QUICKI higher in WC- than in WC+. In WC+H, leptin and QUICKI were significantly less disturbed than in WC+L and were independently correlated to MPO (r = -0.36 and r = 0.32 respectively; p < 0.001). In WC+, when visceral perimeter was added to the analysis, the relationships MPO/leptin remained significant but not MPO/QUICKI. CONCLUSION The low PF in subjects with abdominal obesity is independently linked to plasma leptin and insulin sensitivity even if leptin and insulin may share common pathways in their peripheral effects. Visceral adiposity participates to the link between MPO and QUICKI, but not between MPO and leptin.
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Affiliation(s)
- Mohamed Ali Saafi
- Laboratoire de Physiologie de l'Exercice, EA 4338, Université de Lyon, Saint-Etienne, France
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Rolo AP, Teodoro JS, Palmeira CM. Role of oxidative stress in the pathogenesis of nonalcoholic steatohepatitis. Free Radic Biol Med 2012; 52:59-69. [PMID: 22064361 DOI: 10.1016/j.freeradbiomed.2011.10.003] [Citation(s) in RCA: 678] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 10/03/2011] [Accepted: 10/04/2011] [Indexed: 02/07/2023]
Abstract
The worldwide rising prevalence of obesity and insulin resistance is associated with a parallel increase in nonalcoholic fatty liver disease (NAFLD). NAFLD is characterized by excess accumulation of triglyceride in the hepatocyte due to increased inflow of free fatty acids and/or de novo lipogenesis caused by various drugs and multiple defects in energy metabolism. Accumulation of lipids in the hepatocyte impairs the oxidative capacity of the mitochondria, increasing the reduced state of the electron transport chain (ETC) complexes and stimulating peroxisomal and microsomal pathways of fat oxidation. The consequent increased generation of reactive oxygen species (ROS) and reactive aldehydic derivatives causes oxidative stress and cell death, via ATP, NAD, and glutathione depletion and DNA, lipid, and protein damage. Oxidative stress also triggers production of inflammatory cytokines, causing inflammation and a fibrogenic response. This ultimately results in the development of nonalcoholic steatohepatitis (NASH), which can result in end-stage liver disease. The current therapeutic strategies for NASH treatment are mostly directed toward correction of the risk factors. Stimulation of mitochondrial function may also prevent NASH development, protecting the cell against the increased flux of reduced substrates to the ETC and ROS generation.
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Affiliation(s)
- Anabela P Rolo
- Center for Neuroscience and Cell Biology, Faculty of Science and Technology, University of Coimbra, Coimbra, Portugal
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