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Esbjörnsson M, Norman B, Persson M, Saini A, Bülow J, Jansson E. Enhanced interleukin-6 in human adipose tissue vein after sprint exercise: Results from a pilot study. Clin Physiol Funct Imaging 2024; 44:171-178. [PMID: 37899535 DOI: 10.1111/cpf.12863] [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: 06/06/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 10/31/2023]
Abstract
BACKGROUND Low-volume sprint exercise is likely to reduce body fat. Interleukin (IL-6) may mediate this by increasing adipose tissue (AT) lipolysis. Therefore, the exchange of AT IL-6 and glycerol, a marker of lipolysis, was examined in 10 healthy subjects performing three 30-s all-out sprints. METHODS Blood samples were obtained from brachial artery (a) and a superficial subcutaneous vein (v) on the anterior abdominal wall up to 9 min after the last sprint and analysed for IL-6 and glycerol. RESULTS Arterial IL-6 increased 2-fold from rest to last sprint. AT venous IL-6 increased 15-fold from 0.4 ± 0.4 at rest to 7.0 ± 4 pg × mL-1 (p < 0.0001) and AT v-a difference increased 45-fold from 0.12 ± 0.3 to 6.0 ± 5 pg x mL-1 (p < 0.0001) 9 min after last sprint. Arterial glycerol increased 2.5-fold from rest to 9 min postsprint 1 (p < 0.0001) and was maintained during the exercise period. AT venous and v-a difference of glycerol increased 2-fold from rest to 9 min postsprint 1 (p < 0.0001 and p = 0.01, respectively), decreased until 18 min postsprint 2 (p < 0.001 and p < 0.0001), and then increased again until 9 min after last sprint (both p < 0.01). CONCLUSIONS The concurrent increase in venous IL-6 and glycerol in AT after last sprint is consistent with an IL-6 induced lipolysis in AT. Glycerol data also indicated an initial increase in lipolysis after sprint 1 that was unrelated to IL-6. Increased IL-6 in adipose tissue may, therefore, complement other sprint exercise-induced lipolytic agents.
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Affiliation(s)
- Mona Esbjörnsson
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, Huddinge, Sweden
- Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Barbara Norman
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, Huddinge, Sweden
| | - Moa Persson
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, Huddinge, Sweden
| | - Amarjit Saini
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, Huddinge, Sweden
| | - Jens Bülow
- Division of Clinical Physiology, Bispebjerg Hospital, Copenhagen, Denmark
| | - Eva Jansson
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, Huddinge, Sweden
- Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
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2
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Orange ST, Leslie J, Ross M, Mann DA, Wackerhage H. The exercise IL-6 enigma in cancer. Trends Endocrinol Metab 2023; 34:749-763. [PMID: 37633799 DOI: 10.1016/j.tem.2023.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/28/2023]
Abstract
Interleukin (IL)-6 elicits both anticancer and procancer effects depending on the context, which we have termed the 'exercise IL-6 enigma'. IL-6 is released from skeletal muscles during exercise to regulate short-term energy availability. Exercise-induced IL-6 provokes biological effects that may protect against cancer by improving insulin sensitivity, stimulating the production of anti-inflammatory cytokines, mobilising immune cells, and reducing DNA damage in early malignant cells. By contrast, IL-6 continuously produced by leukocytes in inflammatory sites drives tumorigenesis by promoting chronic inflammation and activating tumour-promoting signalling pathways. How can a molecule have such opposing effects on cancer? Here, we review the roles of IL-6 in chronic inflammation, tumorigenesis, and exercise-associated cancer prevention and define the factors that underpin the exercise IL-6 enigma.
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Affiliation(s)
- Samuel T Orange
- Newcastle University Centre for Cancer, Newcastle University, Newcastle upon Tyne, UK; School of Biomedical, Nutritional and Sport Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.
| | - Jack Leslie
- Newcastle University Centre for Cancer, Newcastle University, Newcastle upon Tyne, UK; Newcastle Fibrosis Research Group, Bioscience Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Mark Ross
- Institute of Life and Earth Sciences, School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh, UK
| | - Derek A Mann
- Newcastle University Centre for Cancer, Newcastle University, Newcastle upon Tyne, UK; Newcastle Fibrosis Research Group, Bioscience Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Henning Wackerhage
- Department of Sport & Health Science, Technical University of Munich, Munich, Germany
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3
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Ren J, Wang XQ, Nakao T, Libby P, Shi GP. Differential Roles of Interleukin-6 in Severe Acute Respiratory Syndrome-Coronavirus-2 Infection and Cardiometabolic Diseases. CARDIOLOGY DISCOVERY 2023; 3:166-182. [PMID: 38152628 PMCID: PMC10750760 DOI: 10.1097/cd9.0000000000000096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can lead to a cytokine storm, unleashed in part by pyroptosis of virus-infected macrophages and monocytes. Interleukin-6 (IL-6) has emerged as a key participant in this ominous complication of COVID-19. IL-6 antagonists have improved outcomes in patients with COVID-19 in some, but not all, studies. IL-6 signaling involves at least 3 distinct pathways, including classic-signaling, trans-signaling, and trans-presentation depending on the localization of IL-6 receptor and its binding partner glycoprotein gp130. IL-6 has become a therapeutic target in COVID-19, cardiovascular diseases, and other inflammatory conditions. However, the efficacy of inhibition of IL-6 signaling in metabolic diseases, such as obesity and diabetes, may depend in part on cell type-dependent actions of IL-6 in controlling lipid metabolism, glucose uptake, and insulin sensitivity owing to complexities that remain to be elucidated. The present review sought to summarize and discuss the current understanding of how and whether targeting IL-6 signaling ameliorates outcomes following SARS-CoV-2 infection and associated clinical complications, focusing predominantly on metabolic and cardiovascular diseases.
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Affiliation(s)
- Jingjing Ren
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Xiao-Qi Wang
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Tetsushi Nakao
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Peter Libby
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Guo-Ping Shi
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
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4
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Fang P, She Y, Yu M, Min W, Shang W, Zhang Z. Adipose-Muscle crosstalk in age-related metabolic disorders: The emerging roles of adipo-myokines. Ageing Res Rev 2023; 84:101829. [PMID: 36563906 DOI: 10.1016/j.arr.2022.101829] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/21/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Obesity and type 2 diabetes account for a considerable proportion of the global burden of age-related metabolic diseases. In age-related metabolic diseases, tissue crosstalk and metabolic regulation have been primarily linked to endocrine processes. Skeletal muscle and adipose tissue are endocrine organs that release myokines and adipokines into the bloodstream, respectively. These cytokines regulate metabolic responses in a variety of tissues, including skeletal muscle and adipose tissue. However, the intricate mechanisms underlying adipose-muscle crosstalk in age-related metabolic diseases are not fully understood. Recent exciting evidence suggests that myokines act to control adipose tissue functions, including lipolysis, browning, and inflammation, whereas adipokines mediate the beneficial actions of adipose tissue in the muscle, such as glucose uptake and metabolism. In this review, we assess the mechanisms of adipose-muscle crosstalk in age-related disorders and propose that the adipokines adiponectin and spexin, as well as the myokines irisin and interleukin-6 (IL-6), are crucial for maintaining the body's metabolic balance in age-related metabolic disorders. In addition, these changes of adipose-muscle crosstalk in response to exercise or dietary flavonoid consumption are part of the mechanisms of both functions in the remission of age-related metabolic disorders. A better understanding of the intricate relationships between adipose tissue and skeletal muscle could lead to more potent therapeutic approaches to prolong life and prevent age-related metabolic diseases.
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Affiliation(s)
- Penghua Fang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Yuqing She
- Department of Endocrinology, Pukou Branch of Jiangsu People's Hospital, Nanjing 211899, China
| | - Mei Yu
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wen Min
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Wenbin Shang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China.
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5
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Yu X, Hussein S, Li L, Liu Q, Ban Z, Jiang H. Effect of Dihydroquercetin on Energy Metabolism in LPS-Induced Inflammatory Mice. BIOMED RESEARCH INTERNATIONAL 2022; 2022:6491771. [PMID: 35832840 PMCID: PMC9273438 DOI: 10.1155/2022/6491771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 12/04/2022]
Abstract
This study investigated the effects and alterations of dihydroquercetin on the growth performance, nutriment metabolism, antioxidant and immune function, and energy substrate utilization in lipopolysaccharide-challenged mice. A total of 0, 50, and 200 mg/kg of dihydroquercetin were intragastrically administered once a day for 21 days. After the pretreatment with dihydroquercetin, each group was subjected to a lipopolysaccharide challenge (except for the control group). After lipopolysaccharide injection, food intake, body weight, metabolic indexes of blood and liver nutrients, blood inflammatory factors, and liver oxidative stress indexes were measured at 6, 12, 24, and 48 h, respectively. Indirect calorimetry analysis was performed by respiratory gas analysis for 48 h to calculate the energy substrate metabolism of carbohydrate, fat, and protein. Urinary nitrogen excretion was measured to evaluate the urinary protein metabolism to calculate the substrate utilization. The results showed that dihydroquercetin pretreatment can significantly increase the weight gain and average food intake and decrease the mortality rate in lipopolysaccharide-induced inflammation mice. Furthermore, dihydroquercetin pretreatment can alleviate the negative effects of lipopolysaccharides by increasing levels of superoxide dismutase and glutathione peroxidase and by decreasing the malondialdehyde and serum inflammatory cytokines (interleukin-1β, nuclear factor κB, and interleukin-6). Dihydroquercetin pretreatment also can relieve nutrient metabolic disorder by increasing blood glucose, serum total protein, and liver glycogen levels and reducing serum and liver triglycerides, serum cholesterol, serum lactate dehydrogenase, and serum urea nitrogen levels. Meanwhile, it increases the relative utilization of carbohydrate, reducing relative utilization of protein and lipid, alleviating the change in energy metabolism pattern from glucose-predominant to lipid-predominant caused by lipopolysaccharide stimulation. In addition, the degree of metabolic pattern transformation depends on the dose of dihydroquercetin supplement. Finally, according to principal component analysis, we found that the inflammation was strongest in the mice at 24 h and was subsequently relieved in the LPS-stimulated group, whereas in the dihydroquercetin-pretreated group, the inflammation was initially relieved. To summarize, dihydroquercetin pretreatment can improve energy metabolism disorder and attenuate the negative effects of lipopolysaccharide challenge in mice from the initial stage of inflammation.
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Affiliation(s)
- Xiaoying Yu
- Department of Animal Science and Technology, Jilin Agricultural University, Jilin Province, Changchun, China 130118
| | - Saddam Hussein
- Department of Animal Science and Technology, Jilin Agricultural University, Jilin Province, Changchun, China 130118
| | - Lijia Li
- Jilin Academy of Agricultural Sciences, No. 1363 Shengtai Street, Changchun City, Jilin Province, China 1300119
| | - Qingyu Liu
- Jilin Academy of Agricultural Sciences, No. 1363 Shengtai Street, Changchun City, Jilin Province, China 1300119
| | - Zhibin Ban
- Jilin Academy of Agricultural Sciences, No. 1363 Shengtai Street, Changchun City, Jilin Province, China 1300119
| | - Hailong Jiang
- Department of Animal Science and Technology, Jilin Agricultural University, Jilin Province, Changchun, China 130118
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Antuna-Puente B, Fellahi S, McAvoy C, Fève B, Bastard JP. Interleukins in adipose tissue: Keeping the balance. Mol Cell Endocrinol 2022; 542:111531. [PMID: 34910978 DOI: 10.1016/j.mce.2021.111531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 02/06/2023]
Abstract
The role of the immune system is to defend the host and preserve the functionality in response to stress. This function is not limited to infection or injury as it also plays a role in the response to overnutrition. Indeed, low-grade chronic activation of the immune system associated with overnutrition may be deleterious, contributing importantly to diabetes and long-term complications, such as cardiovascular disorders. Increasing evidence shows that adipose tissue participates in the obesity-related inflammatory response and that interleukins are one of the key players, either as a pro-inflammatory response to the metabolic dysregulation or to restore homeostasis. The crosstalk between adipocytes and immune cells through some important interleukins and their role in metabolic disruption is the topic of this review.
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Affiliation(s)
- Barbara Antuna-Puente
- Infection Disease Division, Department of Medicine, Queen's University, Kingston, ON, Canada.
| | - Soraya Fellahi
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Henri Mondor, Département de Biochimie-pharmacologie-biologie Moléculaire-génétique Médicale, Créteil, France; Sorbonne Université-Inserm, Centre de Recherche Saint-Antoine UMR S_938, 75012, Paris Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Paris, France
| | - Chloé McAvoy
- Unité de Recherche Clinique de L'Est Parisien (URC-Est), Hôpital Saint Antoine, Paris, France
| | - Bruno Fève
- Sorbonne Université-Inserm, Centre de Recherche Saint-Antoine UMR S_938, 75012, Paris Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Paris, France; Assistance Publique- Hôpitaux de Paris -Hôpital Saint-Antoine, Service D'Endocrinologie-Diabétologie, Centre de Référence des Maladies Rares de L'Insulino-Sécrétion et de L'Insulino-Sensibilité (PRISIS), 75012, Paris, France
| | - Jean-Philippe Bastard
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Henri Mondor, Département de Biochimie-pharmacologie-biologie Moléculaire-génétique Médicale, Créteil, France; FHU-SENEC, INSERM U955 and Université Paris Est (UPEC), UMR U955, Faculté de Santé, Créteil, France
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7
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Blocking endogenous IL-6 impairs mobilization of free fatty acids during rest and exercise in lean and obese men. CELL REPORTS MEDICINE 2021; 2:100396. [PMID: 34622233 PMCID: PMC8484687 DOI: 10.1016/j.xcrm.2021.100396] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/03/2021] [Accepted: 08/17/2021] [Indexed: 12/26/2022]
Abstract
Lack of interleukin-6 (IL-6) leads to expansion of adipose tissue mass in rodents and humans. The exact underlying mechanisms have not been identified. In this placebo-controlled, non-randomized, participant-blinded crossover study, we use the IL-6 receptor antibody tocilizumab to investigate the role of endogenous IL-6 in regulating systemic energy metabolism at rest and during exercise and recovery in lean and obese men using tracer dilution methodology. Tocilizumab reduces fatty acid appearance in the circulation under all conditions in lean and obese individuals, whereas lipolysis (the rate of glycerol appearance into the circulation) is mostly unaffected. The fact that fatty acid oxidation is unaffected by IL-6 receptor blockade suggests increased re-esterification of fatty acids. Glucose kinetics are unaffected. We find that blocking endogenous IL-6 signaling with tocilizumab impairs fat mobilization, which may contribute to expansion of adipose tissue mass and, thus, affect the health of individuals undergoing anti-IL-6 therapy (Clinicaltrials.gov: NCT03967691).
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8
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Vasyukova OV, Kasyanova YV, Okorokov PL, Bezlepkina OB. [Myokines and adipomyokines: inflammatory mediators or unique molecules of targeted therapy for obesity?]. ACTA ACUST UNITED AC 2021; 67:36-45. [PMID: 34533012 DOI: 10.14341/probl12779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 11/06/2022]
Abstract
Skeletal muscles make up about 25% of the total mass in children and more than 40% in adults. Studies of the last twenty years have shown that along with the main functions, muscle tissue has hormonal activity. It was found that myocytes are able to release signaling molecules-myokines. They act auto-and paracrine within the muscle, and at a high level-through the systemic circulation, carrying out interactions between skeletal muscles and various organs and tissues, such as the liver, bone and adipose tissue, the brain. It is proved that the key factor in the expression of myokines is physical activity, and their level largely depends on physical fitness, the amount of skeletal muscle mass and its composition (the ratio of fast and slow fibers), on the intensity and duration of physical activity. Myokines have a wide range of physiological effects: myostatin suppresses the growth and differentiation of muscle tissue, and decorin, acting as its antagonist, promotes muscle hypertrophy. Interleukin 6 provides an energy substrate for contracting muscle fibers, fibroblast growth factor 21 activates the mechanisms of energy production during fasting and improves tissue sensitivity to insulin; irisin stimulates thermogenesis, glucose uptake by myocytes, and also contributes to an increase in bone mineral density. The study of myokines is one of the key links in understanding the mechanisms underlying obesity and metabolic complications, the consequences of a sedentary lifestyle, as well as the implementation of the action of physical activity. Taking into account the physiological effects of myokines in the body, in the future they can become therapeutic targets for the treatment of these conditions.
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Effect of treatment with conditioned media derived from C2C12 myotube on adipogenesis and lipolysis in 3T3-L1 adipocytes. PLoS One 2020; 15:e0237095. [PMID: 32756599 PMCID: PMC7406041 DOI: 10.1371/journal.pone.0237095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/20/2020] [Indexed: 01/04/2023] Open
Abstract
Regular exercise is an effective strategy that is used to prevent and treat obesity as well as type 2 diabetes. Exercise-induced myokine secretion is considered a mechanism that coordinates communication between muscles and other organs. In order to examine the possibility of novel communications from muscle to adipose tissue mediated by myokines, we treated 3T3-L1 adipocytes with C2C12 myotube electrical pulse stimulation-conditioned media (EPS-CM), using a C2C12 myotube contraction system stimulated by an electrical pulse. Continuous treatment with myotube EPS-CM promoted adipogenesis of 3T3-L1 pre-adipocytes via the upregulation of the peroxisome proliferator-activated receptor-gamma (PPARγ) 2 and PPARγ-regulated gene expression. Furthermore, our results revealed that myotube EPS-CM induces lipolysis and secretion of adiponectin in mature adipocytes. EPS-CM obtained from a C2C12 myoblast culture did not induce such changes in these genes, suggesting that contraction-induced myokine(s) secretion occurs particularly in differentiated myotubes. Thus, contraction-induced secretion of myokine(s) promotes adipogenesis and lipid metabolism in 3T3-L1 adipocytes. These findings suggest the possibility that skeletal muscle communicates to adipose tissues during exercise, probably by the intermediary of unidentified myokines.
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Baek KW, Lee DI, Kang SA, Yu HS. Differences in macrophage polarization in the adipose tissue of obese mice under various levels of exercise intensity. J Physiol Biochem 2020; 76:159-168. [PMID: 32062818 DOI: 10.1007/s13105-020-00731-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 02/07/2020] [Indexed: 12/20/2022]
Abstract
Animal studies have demonstrated that the ratio of M1 (M1Φ) to M2 (M2Φ) macrophage-specific gene expression in adipose tissue (AT) may be altered by chronic exercise; however, whether macrophage polarization is induced under these conditions has not yet been reported. Therefore, this study aimed to investigate the effect of chronic exercise on M1Φ/M2Φ polarization in the AT of high-fat diet (HFD)-induced obese mice. Exercise-induced differences in M1Φ/M2Φ polarization were verified via an exercise intensity study (EIS) in which different levels of exercise intensity were evaluated. Obesity was induced in male C57BL/6 J mice by feeding them with an HFD for 6 weeks. The study consisted of four groups: control group (CON), HFD-fed group (HFD), HFD-fed with exercise group (HFD + EXE), dietary conversion from HFD to normal diet (ND) group (DC), and dietary conversion from HFD to ND group (DC + EXE). For EIS, the HFD + EXE group was divided into three subgroups: low- (LI), mid- (MI), and high- (HI) intensity exercise. The total intervention period was 8 weeks. M1Φ/M2Φ polarization was confirmed by flow cytometry. M2Φ polarization in the AT of obese mice was significantly higher in HFD + EXE mice than in HFD mice, despite the HFD intake. In the EIS, M2Φ polarization was most pronounced in HFD + EXE-HI mice than in HFD mice. It can be proposed that the enhanced insulin resistance and inflammation by obesity can be improved by the increase of M2Φ polarization which is achieved by relatively high-intensity exercise.
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Affiliation(s)
- Kyung-Wan Baek
- Division of Sport Science, Pusan National University, Busan, South Korea
- Department of Parasitology and Tropical Medicine, Pusan National University School of Medicine, Yangsan, South Korea
| | - Da-In Lee
- Department of Parasitology and Tropical Medicine, Pusan National University School of Medicine, Yangsan, South Korea
| | - Shin Ae Kang
- Department of Parasitology and Tropical Medicine, Pusan National University School of Medicine, Yangsan, South Korea
| | - Hak Sun Yu
- Department of Parasitology and Tropical Medicine, Pusan National University School of Medicine, Yangsan, South Korea.
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Kang S, Tanaka T, Narazaki M, Kishimoto T. Targeting Interleukin-6 Signaling in Clinic. Immunity 2019; 50:1007-1023. [PMID: 30995492 DOI: 10.1016/j.immuni.2019.03.026] [Citation(s) in RCA: 506] [Impact Index Per Article: 101.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/20/2019] [Accepted: 03/26/2019] [Indexed: 02/08/2023]
Abstract
Interleukin-6 (IL-6) is a pleiotropic cytokine with roles in immunity, tissue regeneration, and metabolism. Rapid production of IL-6 contributes to host defense during infection and tissue injury, but excessive synthesis of IL-6 and dysregulation of IL-6 receptor signaling is involved in disease pathology. Therapeutic agents targeting the IL-6 axis are effective in rheumatoid arthritis, and applications are being extended to other settings of acute and chronic inflammation. Recent studies reveal that selective blockade of different modes of IL-6 receptor signaling has different outcomes on disease pathology, suggesting novel strategies for therapeutic intervention. However, some inflammatory diseases do not seem to respond to IL-6 blockade. Here, we review the current state of IL-6-targeting approaches in the clinic and discuss how to apply the growing understanding of the immunobiology of IL-6 to clinical decisions.
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Affiliation(s)
- Sujin Kang
- Department of Immune Regulation, Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, Japan
| | - Toshio Tanaka
- Medical Affairs Bureau, Osaka Habikino Medical Center, 3-7-1 Habikino, Habikino City, Osaka, Japan
| | - Masashi Narazaki
- Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita City, Osaka, Japan; Department of Immunopathology, Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, Japan
| | - Tadamitsu Kishimoto
- Department of Immune Regulation, Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, Japan.
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12
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The role of interleukin-6 in glucose homeostasis and lipid metabolism. Semin Immunopathol 2019; 41:491-499. [PMID: 31101976 DOI: 10.1007/s00281-019-00747-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023]
Abstract
Low-grade inflammation is recognized as an important factor in the development and progression of a multitude of diseases including type 2 diabetes mellitus and cardiovascular disease. The potential of using antibody-based therapies that neutralize key players of low-grade inflammation has gained scientific momentum as a novel therapeutic strategy in metabolic diseases. As interleukin-6 (IL-6) is traditionally considered a key pro-inflammatory factor, the potential of expanding the use of anti-IL-6 therapies to metabolic diseases is intriguing. However, IL-6 is a molecule of a very pleiotropic nature that regulates many aspects of not only inflammation but also metabolism. In this review, we give a brief overview of the pro- and anti-inflammatory aspects of IL-6 and provide an update on its role in metabolic regulation, with a specific focus on glucose homeostasis and adipose tissue metabolism. Finally, we shall discuss the metabolic implications and clinical potential of blocking IL-6 signaling, focusing on glucose homeostasis and lipid metabolism.
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13
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Pendharkar SA, Singh RG, Petrov MS. Pro-inflammatory cytokine-induced lipolysis after an episode of acute pancreatitis. Arch Physiol Biochem 2018; 124:401-409. [PMID: 29235373 DOI: 10.1080/13813455.2017.1415359] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Pro-inflammatory cytokine-stimulated lipolysis is one of the mechanisms underlying the pathogenesis of type 2 diabetes. However, whether it plays a role in the pathogenesis of post-pancreatitis diabetes mellitus (PPDM) remains unknown. OBJECTIVE To investigate the associations between markers of lipid metabolism and pro-inflammatory cytokines in individuals after acute pancreatitis (AP) in general, and in individuals with abnormal glucose metabolism (AGM) following AP in particular. METHODS Fasting blood samples were collected to measure markers of lipid metabolism (apolipoprotein-B, cholesterol, free fatty acids (FFA), glycerol, high and low-density lipoproteins, triglycerides) and cytokines (interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and tumour necrosis factor (TNF) α). Linear regression analysis was conducted. Four statistical models were used to adjust for patient- and pancreatitis-related characteristics. RESULTS A total of 83 patients were recruited. IL-6 was significantly associated with glycerol in all models (p < .05), with glycerol levels increasing by 106% in individuals with AGM after AP (p <.05) compared to a 30.3% increase in individuals with normal glucose metabolism (NGM) (p >.05). TNFα was significantly associated with FFA (p = .015) in individuals with AGM after AP in the most adjusted model, with FFA levels increasing by 314% in these individuals compared to a 162% decrease in individuals with NGM after AP (p >.05). CONCLUSIONS Lipolysis appears to be an important pathogenetic mechanism in glucose derangements after diseases of the exocrine pancreas. IL-6 and TNFα are the driving forces behind lipolysis in individuals with AGM after AP. Modulation of lipolysis may be a promising therapeutic modality.
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Affiliation(s)
| | - Ruma G Singh
- a School of Medicine , University of Auckland , Auckland , New Zealand
| | - Maxim S Petrov
- a School of Medicine , University of Auckland , Auckland , New Zealand
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Xu Y, Zhang Y, Ye J. IL-6: A Potential Role in Cardiac Metabolic Homeostasis. Int J Mol Sci 2018; 19:ijms19092474. [PMID: 30134607 PMCID: PMC6164544 DOI: 10.3390/ijms19092474] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022] Open
Abstract
Interleukin-6 (IL-6) is implicated in multiple biological functions including immunity, neural development, and haematopoiesis. Recently, mounting evidence indicates that IL-6 plays a key role in metabolism, especially lipid metabolic homeostasis. A working heart requires a high and constant energy input which is largely generated by fatty acid (FA) β-oxidation. Under pathological conditions, the precise balance between cardiac FA uptake and metabolism is perturbed so that excessive FA is accumulated, thereby predisposing to myocardial dysfunction (cardiac lipotoxicity). In this review, we summarize the current evidence that suggests the involvement of IL-6 in lipid metabolism. Cardiac metabolic features and consequences of myocardial lipotoxicity are also briefly analyzed. Finally, the roles of IL-6 in cardiac FA uptake (i.e., serum lipid profile and myocardial FA transporters) and FA metabolism (namely, β-oxidation, mitochondrial function, biogenesis, and FA de novo synthesis) are discussed. Overall, understanding how IL-6 transmits signals to affect lipid metabolism in the heart might allow for development of better clinical therapies for obesity-associated cardiac lipotoxicity.
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Affiliation(s)
- Yitao Xu
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London W120NN, UK.
| | - Yubin Zhang
- State Key laboratory of Natural Medicines, Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China.
| | - Junmei Ye
- State Key laboratory of Natural Medicines, Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China.
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15
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Ghanemi A, St-Amand J. Interleukin-6 as a "metabolic hormone". Cytokine 2018; 112:132-136. [PMID: 29983356 DOI: 10.1016/j.cyto.2018.06.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 06/22/2018] [Accepted: 06/30/2018] [Indexed: 12/11/2022]
Abstract
Interleukin 6 (IL-6) is a cytokine that is involved in divers immune responses and implicated in a number of diseases. However, this cytokine has other non-immune functions. Within this review, we highlight selected effects on metabolic pathways, which are mediated, controlled or modified by the IL-6. Importantly, putting spotlight on such concepts could allow us to classify IL-6 among the metabolic hormones and further study it to both deepen our knowledge on disorders involving metabolic or energy imbalances such as obesity and develop novel therapeutic strategies. Furthermore, potential explanations related to IL-6 roles in both physiology and pathology as well as relevant implications and applications on both research and therapeutic fields are also pointed as consequences of the involvement of IL-6 in the energy and metabolic homeostasis via its "endocrine" roles.
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Affiliation(s)
- Abdelaziz Ghanemi
- Department of Molecular Medicine, Faculty of Medicine, Laval University, Quebec G1V 0A6, Canada; Functional Genomics Laboratory, CREMI, Québec Genome Center, CHUL-CHU de Québec Research Center, Québec, Québec G1V 4G2, Canada
| | - Jonny St-Amand
- Department of Molecular Medicine, Faculty of Medicine, Laval University, Quebec G1V 0A6, Canada; Functional Genomics Laboratory, CREMI, Québec Genome Center, CHUL-CHU de Québec Research Center, Québec, Québec G1V 4G2, Canada.
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16
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A system model of the effects of exercise on plasma Interleukin-6 dynamics in healthy individuals: Role of skeletal muscle and adipose tissue. PLoS One 2017; 12:e0181224. [PMID: 28704555 PMCID: PMC5507524 DOI: 10.1371/journal.pone.0181224] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 06/27/2017] [Indexed: 12/25/2022] Open
Abstract
Interleukin-6 (IL-6) has been recently shown to play a central role in glucose homeostasis, since it stimulates the production and secretion of Glucagon-like Peptide-1 (GLP-1) from intestinal L-cells and pancreas, leading to an enhanced insulin response. In resting conditions, IL-6 is mainly produced by the adipose tissue whereas, during exercise, skeletal muscle contractions stimulate a marked IL-6 secretion as well. Available mathematical models describing the effects of exercise on glucose homeostasis, however, do not account for this IL-6 contribution. This study aimed at developing and validating a system model of exercise’s effects on plasma IL-6 dynamics in healthy humans, combining the contributions of both adipose tissue and skeletal muscle. A two-compartment description was adopted to model plasma IL-6 changes in response to oxygen uptake’s variation during an exercise bout. The free parameters of the model were estimated by means of a cross-validation procedure performed on four different datasets. A low coefficient of variation (<10%) was found for each parameter and the physiologically meaningful parameters were all consistent with literature data. Moreover, plasma IL-6 dynamics during exercise and post-exercise were consistent with literature data from exercise protocols differing in intensity, duration and modality. The model successfully emulated the physiological effects of exercise on plasma IL-6 levels and provided a reliable description of the role of skeletal muscle and adipose tissue on the dynamics of plasma IL-6. The system model here proposed is suitable to simulate IL-6 response to different exercise modalities. Its future integration with existing models of GLP-1-induced insulin secretion might provide a more reliable description of exercise’s effects on glucose homeostasis and hence support the definition of more tailored interventions for the treatment of type 2 diabetes.
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17
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Nieman DC, Sha W, Pappan KL. IL-6 Linkage to Exercise-Induced Shifts in Lipid-Related Metabolites: A Metabolomics-Based Analysis. J Proteome Res 2017; 16:970-977. [PMID: 27996272 DOI: 10.1021/acs.jproteome.6b00892] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Metabolomics profiling and bioinformatics technologies were used to determine the relationship between exercise-induced increases in IL-6 and lipid-related metabolites. Twenty-four male runners (age 36.5 ± 1.8 y) ran on treadmills to exhaustion (2.26 ± 0.01 h, 24.9 ± 1.3 km, 69.7 ± 1.9% VO2max). Vastus lateralis muscle biopsy and blood samples were collected before and immediately after running and showed a 33.7 ± 4.2% decrease in muscle glycogen, 39.0 ± 8.8-, 2.4 ± 0.3-, and 1.4 ± 0.1-fold increases in plasma IL-6, IL-8, and MCP-1, respectively, and 95.0 ± 18.9 and 158 ± 20.6% increases in cortisol and epinephrine, respectively (all, P < 0.001). The metabolomics analysis revealed changes in 209 metabolites, especially long- and medium-chain fatty acids, fatty acid oxidation products (dicarboxylate and monohydroxy fatty acids, acylcarnitines), and ketone bodies. OPLS-DA modeling supported a strong separation in pre- and post-exercise samples (R2Y = 0.964, Q2Y = 0.902). OPLSR analysis failed to produce a viable model for the relationship between IL-6 and all lipid-related metabolites (R2Y = 0.76, Q2Y = -0.0748). Multiple structure equation models were evaluated based on IL-6, with the best-fit pathway model showing a linkage of exercise time to IL-6, then carnitine, and 13-methylmyristic acid (a marker for adipose tissue lipolysis) and sebacate. These metabolomics-based data indicate that the increase in plasma IL-6 after long endurance running has a minor relationship to increases in lipid-related metabolites.
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Affiliation(s)
- David C Nieman
- Human Performance Laboratory, Appalachian State University , North Carolina Research Campus, Kannapolis, North Carolina 28081, United States
| | - Wei Sha
- Bioinformatics Services Division, University of North Carolina at Charlotte , North Carolina Research Campus, Kannapolis, North Carolina 28081, United States
| | - Kirk L Pappan
- Metabolon, Inc. , Durham, North Carolina 27713, United States
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18
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Mapping inflammation onto mood: Inflammatory mediators of anhedonia. Neurosci Biobehav Rev 2016; 64:148-66. [PMID: 26915929 DOI: 10.1016/j.neubiorev.2016.02.017] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 11/30/2015] [Accepted: 02/18/2016] [Indexed: 12/20/2022]
Abstract
Evidence supports inflammatory involvement in mood and cognitive symptoms across psychiatric, neurological and medical disorders; however, inflammation is not a sensitive or specific characteristic of these diagnoses. The National Institute of Mental Health Research Domain Criteria (RDoC) ask for a shift away from symptom-based diagnoses toward a transdiagnostic neurobiological focus in the study of brain illnesses. The RDoC matrix may provide a useful framework for integrating the effects of inflammation on brain function. Based on preclinical and clinical findings, relevant relationships span negative and positive valence systems, cognitive systems, systems for social processes and arousal/regulatory systems. As an exemplar, we consider the psychopathological domain of anhedonia, conceptualizing the relevance of inflammation (e.g., cellular immunity) and downstream processes (e.g., indoleamine 2,3-dioxygenase activation and oxidative inactivation of tetrahydrobiopterin) across RDoC units of analysis (e.g., catecholamine neurotransmitter molecules, nucleus accumbens medium spiny neuronal cells, dopaminergic mesolimbic and mesocortical reward circuits, animal paradigms, etc.). We discuss implications across illnesses affecting the brain, including infection, major depressive disorder, stroke, Alzheimer's disease and type 2 diabetes.
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Lerner L, Hayes TG, Tao N, Krieger B, Feng B, Wu Z, Nicoletti R, Chiu MI, Gyuris J, Garcia JM. Plasma growth differentiation factor 15 is associated with weight loss and mortality in cancer patients. J Cachexia Sarcopenia Muscle 2015; 6:317-24. [PMID: 26672741 PMCID: PMC4670740 DOI: 10.1002/jcsm.12033] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/24/2015] [Accepted: 03/16/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Cancer-related weight loss is associated with increased inflammation and decreased survival. The novel inflammatory mediator growth differentiation factor (GDF)15 is associated with poor prognosis in cancer but its role in cancer-related weight loss (C-WL) remains unclear. Our objective was to measure GDF15 in plasma samples of cancer subjects and controls and establish its association with other inflammatory markers and clinical outcomes. METHODS We measured body weight, appetite, plasma GDF15, and other inflammatory markers in men with cancer-related weight loss (C-WL, n = 58), weight stable patients with cancer (C-WS, n = 72), and non-cancer controls (Co, n = 59) matched by age and pre-illness body mass index. In a subset of patients we also measured handgrip strength, appendicular lean body mass (aLBM), Eastern Cooperative Oncology Group (ECOG), and Karnofsky performance scores. RESULTS GDF15, interleukin (IL)-6 and IL-8 were increased in C-WL versus other groups. IL-1 receptor antagonist, IL-4, interferon-gamma, tumour necrosis factor alpha, and vascular endothelial growth factor A were increased in C-WL versus C-WS, and Activin A was significantly downregulated in Co versus other groups. C-WL patients had lower handgrip strength, aLBM, and fat mass, and Eastern Cooperative Oncology Group and Karnofsky performance scores were lower in both cancer groups. GDF15, IL-6, and IL-8 significantly correlated with weight loss; GDF15 negatively correlated with aLBM, handgrip strength, and fat mass. IL-8 and Activin A negatively correlated with aLBM and fat mass. GDF15 and IL-8 predicted survival adjusting for stage and weight change (Cox regression P < 0.001 for both). CONCLUSION GDF15 and other inflammatory markers are associated with weight loss, decreased aLBM and strength, and poor survival in patients with cancer. GDF15 may serve as a prognostic indicator in cancer patients and is being evaluated as a potential therapeutic target for cancer-related weight loss.
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Affiliation(s)
| | - Teresa G Hayes
- Department of Medicine, Center for Translational Research on Inflammatory Diseases (CTRID), Michael E DeBakey Veterans Affairs Medical Center Houston, TX, USA ; Dan L. Duncan Cancer Center, Baylor College of Medicine Houston, TX, USA
| | | | | | - Bin Feng
- AVEO Pharmaceuticals Cambridge, MA, USA
| | | | | | | | | | - Jose M Garcia
- Department of Medicine, Center for Translational Research on Inflammatory Diseases (CTRID), Michael E DeBakey Veterans Affairs Medical Center Houston, TX, USA ; Dan L. Duncan Cancer Center, Baylor College of Medicine Houston, TX, USA ; Department of Molecular and Cell Biology and Huffington Center on Aging, Baylor College of Medicine Houston, TX, USA
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20
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Tsoli M, Swarbrick MM, Robertson GR. Lipolytic and thermogenic depletion of adipose tissue in cancer cachexia. Semin Cell Dev Biol 2015; 54:68-81. [PMID: 26529279 DOI: 10.1016/j.semcdb.2015.10.039] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/26/2015] [Indexed: 01/04/2023]
Abstract
Although muscle wasting is the obvious manifestation of cancer cachexia that impacts on patient quality of life, the loss of lipid reserves and metabolic imbalance in adipose tissue also contribute to the devastating impact of cachexia. Depletion of fat depots in cancer patients is more pronounced than loss of muscle and often precedes, or even occurs in the absence of, reduced lean body mass. Rapid mobilisation of triglycerides stored within adipocytes to supply the body with fatty acids in periods of high-energy demand is normally mediated through a well-defined process of lipolysis involving the lipases ATGL, HSL and MGL. Studies into how these lipases contribute to fat loss in cancer cachexia have revealed the prominent role for ATGL in initiating lipolysis during adipose tissue atrophy, together with links between tumour-derived factors and the signalling pathways that control lipid flux within fat cells. The recent findings of increased thermogenesis in brown fat during cancer cachexia indicate that metabolically active adipose tissue contributes to the imbalance in energy homeostasis involved in catabolic wasting. Such energetically futile use of fatty acids liberated from adipose tissue to generate heat represents a maladaptive response in conjunction with anorexia experienced by cancer patients. As IL-6 release by tumours provokes lipolysis and activates the thermogenic programme in brown fat, this review explores the overlap in dysregulated metabolic processes due to inflammatory mediators in cancer cachexia and other disease states characterised by elevated cytokines such as obesity and diabetes.
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Affiliation(s)
- Maria Tsoli
- Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Randwick, NSW 2031, Australia
| | - Michael M Swarbrick
- Centre for Diabetes, Obesity and Endocrinology, The Westmead Institute for Medical Research, The University of Sydney, NSW, Australia
| | - Graham R Robertson
- School of Molecular Biosciences, University of Sydney, NSW 2006, Australia.
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21
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Phillips NA, Welc SS, Wallet SM, King MA, Clanton TL. Protection of intestinal injury during heat stroke in mice by interleukin-6 pretreatment. J Physiol 2015; 593:739-52; discussion 753. [PMID: 25433073 DOI: 10.1113/jphysiol.2014.283416] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 11/20/2014] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Heat stroke afflicts thousands of humans each year, worldwide. The immune system responds to hyperthermia exposure resulting in heat stroke by producing an array of immunological proteins, such as interleukin-6 (IL-6). However, the physiological functions of IL-6 and other cytokines in hyperthermia are poorly understood. We hypothesized that IL-6 plays a protective role in conditions of heat stroke. To test this, we gave small IL-6 supplements to mice prior to exposing them to hot environments sufficient to induce conditions of heat stroke. Pretreatment with IL-6 resulted in improved ability to withstand heat exposure in anaesthetized mice, it protected the intestine from injury, reducing the permeability of the intestinal barrier, and it attenuated the release of other cytokines involved in inflammation. The results support the hypothesis that IL-6 is a 'physiological stress hormone' that plays an important role in survival during acute life-threatening conditions such as heat stroke. ABSTRACT The role of interleukin-6 (IL-6) in hyperthermia and heat stroke is poorly understood. Plasma IL-6 is elevated following hyperthermia in animals and humans, and IL-6 knockout mice are more intolerant of severe hyperthermia. We evaluated the effect of IL-6 supplementation on organ injury following severe hyperthermia exposure in anaesthetized mice. Two hours prior to hyperthermia, mice were treated with 0.6 μg intraperitoneal IL-6, or identical volumes of saline in controls. Mice were anaesthetized, gavaged with FITC-dextran for measures of gastrointestinal permeability, and exposed to incremental (0.5°C every 30 min) increases in temperature. Heating stopped when maximum core temperature (Tc) of 42.4°C was attained (Tc,max). The mice recovered at room temperature (≈22°C) for 30 or 120 min, at which time plasma and tissues were collected. IL-6-treated mice, on average, required ≈25 min longer to attain Tc,max . Injury and swelling of the villi in the duodenum was present in untreated mice after 30 min of recovery. These changes were blocked by IL-6 treatment. IL-6 also reduced gastrointestinal permeability, assayed by the accumulation of FITC-dextran in plasma. Plasma cytokines were also attenuated in IL-6-treated animals, including significant reductions in TNFα, MCP-1 (CXCL2), RANTES (CCL5) and KC (CCL5). The results demonstrate that IL-6 has a protective influence on the pattern of physiological responses to severe hyperthermia, suggesting that early endogenous expression of IL-6 may provide a protection from the development of organ damage and inflammation.
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Affiliation(s)
- Neil A Phillips
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
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22
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Anamorelin for patients with cancer cachexia: an integrated analysis of two phase 2, randomised, placebo-controlled, double-blind trials. Lancet Oncol 2014; 16:108-16. [PMID: 25524795 DOI: 10.1016/s1470-2045(14)71154-4] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cancer anorexia-cachexia syndrome is associated with increased morbidity and mortality. Anamorelin is an oral ghrelin-receptor agonist with appetite-enhancing and anabolic activity. We assessed the effects of anamorelin on body composition, strength, quality of life, biochemical markers, and safety in patients with cancer anorexia-cachexia. METHODS Data were pooled, a priori, from two completed phase 2, multicentre, placebo-controlled, double-blind trials in patients with advanced or incurable cancer and weight loss of 5% or more. Patients were stratified by weight loss severity (5-15%, >15%) and randomly allocated (1:1) with a computer-generated randomisation schedule to anamorelin hydrochloride 50 mg or placebo once-daily for 12 weeks. Primary outcome was lean body mass by dual-energy x-ray absorptiometry over the 12 week treatment period in eligible patients who had at least one dose of study drug and post-treatment efficacy assessment. We assessed safety in all patients who received at least one dose of study drug. The trials are registered with ClinicalTrials.gov, numbers NCT00219817 and NCT00267358. FINDINGS Between June 29, 2005, and Oct 26, 2006, we enrolled 44 patients in the anamorelin group and 38 patients in the placebo group. 74 patients were eligible for the efficacy analyses. Over 12 weeks, lean body mass increased in 38 patients in the anamorelin group by a least-squares mean of 1.89 kg (95% CI 0.84 to 2.95) compared with a decrease of a least-squares mean of -0.20 kg (-1.23 to 0.83) for 36 patients in the placebo group (difference 2.09 kg [0.94-3.25]; p=0.0006). 42 (95%) of 44 patients treated with anamorelin and 33 (87%) of 38 patients treated with placebo had adverse events. The most common grade 3-4 adverse events (treatment-related or not) in the anamorelin group were fatigue, asthenia, atrial fibrillation, and dyspnoea (two [5%] each); in the placebo group, such events were pneumonia (three [8%]) and anaemia, thrombocytopenia, abdominal pain, anxiety, and dyspnoea (two [5%] each). INTERPRETATION Anamorelin treatment for 12 weeks had a favourable clinical response profile in patients with cancer anorexia-cachexia syndrome. These findings support further investigation in this setting. FUNDING Helsinn Therapeutics (US), Helsinn Healthcare SA.
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Gómez-Gómez E, Ríos-Martínez ME, Castro-Rodríguez EM, Del-Toro-Equíhua M, Ramírez-Flores M, Delgado-Enciso I, Pérez-Huitimea AL, Baltazar-Rodríguez LM, Velasco-Pineda G, Muñiz-Murguía J. Carnitine palmitoyltransferase 1B 531K allele carriers sustain a higher respiratory quotient after aerobic exercise, but β3-adrenoceptor 64R allele does not affect lipolysis: a human model. PLoS One 2014; 9:e96791. [PMID: 24905907 PMCID: PMC4048163 DOI: 10.1371/journal.pone.0096791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/11/2014] [Indexed: 11/28/2022] Open
Abstract
Carnitine palmitoyltransferase IB (CPT1B) and adrenoceptor beta-3 (ADRB3) are critical regulators of fat metabolism. CPT1B transports free acyl groups into mitochondria for oxidation, and ADRB3 triggers lipolysis in adipocytes, and their respective polymorphisms E531K and W64R have been identified as indicators of obesity in population studies. It is therefore important to understand the effects of these mutations on ADRB3 and CPT1B function in adipose and skeletal muscle tissue, respectively. This study aimed to analyze the rate of lipolysis of plasma indicators (glycerol, free fatty acids, and beta hydroxybutyrate) and fat oxidation (through the non-protein respiratory quotient). These parameters were measured in 37 participants during 30 min of aerobic exercise at approximately 62% of maximal oxygen uptake, followed by 30 min of recovery. During recovery, mean respiratory quotient values were higher in K allele carriers than in non-carriers, indicating low post-exercise fatty acid oxidation rates. No significant differences in lipolysis or lipid oxidation were observed between R and W allele carriers of ADRB3 at any time during the aerobic load. The substitution of glutamic acid at position 531 by lysine in the CPT1B protein decreases the mitochondrial beta-oxidation pathway, which increases the non-protein respiratory quotient value during recovery from exercise. This may contribute to weight gain or reduced weight-loss following exercise.
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Affiliation(s)
- Eduardo Gómez-Gómez
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Colima, México
| | | | | | | | - Mario Ramírez-Flores
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Colima, México
| | | | - Ana Lilia Pérez-Huitimea
- Educación Física y Deporte. Facultad de Ciencias de la Educación, Universidad de Colima, Colima, Colima, México
| | | | | | - Jesús Muñiz-Murguía
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Colima, México
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Ajuwon KM. Chronic immune stimulation in adipose tissue and its consequences for health and performance in the pig. Vet Immunol Immunopathol 2014; 159:166-70. [DOI: 10.1016/j.vetimm.2014.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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25
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Banke E, Rödström K, Ekelund M, Dalla-Riva J, Lagerstedt JO, Nilsson S, Degerman E, Lindkvist-Petersson K, Nilson B. Superantigen activates the gp130 receptor on adipocytes resulting in altered adipocyte metabolism. Metabolism 2014; 63:831-40. [PMID: 24684823 DOI: 10.1016/j.metabol.2014.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/25/2014] [Accepted: 03/04/2014] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The bacteria Staphylococcus aureus is part of the normal bacterial flora and produces a repertoire of enterotoxins which can cause food poisoning and toxic shock and might contribute to the pathogenesis of inflammatory diseases. These enterotoxins directly cross-link the T cell receptor with MHC class II, activating large amounts of T cells and are therefore called superantigens. It was recently discovered that the superantigen SEA binds to the cytokine receptor gp130. As obesity and type 2 diabetes are highly associated with inflammation of the adipose tissue and gp130 has been shown to play an important role in adipocytes, we wanted to investigate the effect of SEA on adipocyte signaling and function. MATERIALS/METHODS Binding of SEA to gp130 was examined using surface plasmon resonance in a cell free system. Effects of SEA on adipocyte signaling, insulin sensitivity and function were studied using western blotting and biological assays for lipolysis, lipogenesis and glucose uptake. RESULTS We demonstrate that SEA binds to gp130 with a medium affinity. Furthermore, SEA induces phosphorylation of a key downstream target, STAT3, in adipocytes. SEA also inhibits insulin-induced activation of PKB and PKB downstream signaling which was associated with reduced basal and insulin induced glucose uptake, reduced lipogenesis as well as reduced ability of insulin to inhibit lipolysis. CONCLUSIONS SEA inhibits insulin signaling as well as insulin biological responses in adipocytes supporting that bacterial infection might contribute to the development of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Elin Banke
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden.
| | - Karin Rödström
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Mikael Ekelund
- Department of Surgery, Skåne University Hospital & Lund University, 221 85 Lund, Sweden
| | - Jonathan Dalla-Riva
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Staffan Nilsson
- Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, 221 00 Lund, Sweden
| | - Eva Degerman
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | | | - Bo Nilson
- Department of Laboratory Medicine, Division of Medicinal Microbiology, Lund University, 223 62 Lund, Sweden; Department of Clinical Microbiology, University and Regional Laboratories in Region Skåne, 221 85 Lund, Sweden
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Cuzzone DA, Weitman ES, Albano NJ, Ghanta S, Savetsky IL, Gardenier JC, Joseph WJ, Torrisi JS, Bromberg JF, Olszewski WL, Rockson SG, Mehrara BJ. IL-6 regulates adipose deposition and homeostasis in lymphedema. Am J Physiol Heart Circ Physiol 2014; 306:H1426-34. [PMID: 24633552 DOI: 10.1152/ajpheart.01019.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lymphedema (LE) is a morbid disease characterized by chronic limb swelling and adipose deposition. Although it is clear that lymphatic injury is necessary for this pathology, the mechanisms that underlie lymphedema remain unknown. IL-6 is a known regulator of adipose homeostasis in obesity and has been shown to be increased in primary and secondary models of lymphedema. Therefore, the purpose of this study was to determine the role of IL-6 in adipose deposition in lymphedema. The expression of IL-6 was analyzed in clinical tissue specimens and serum from patients with or without LE, as well as in two mouse models of lymphatic injury. In addition, we analyzed IL-6 expression/adipose deposition in mice deficient in CD4(+) cells (CD4KO) or IL-6 expression (IL-6KO) or mice treated with a small molecule inhibitor of IL-6 or CD4 depleting antibodies to determine how IL-6 expression is regulated and the effect of changes in IL-6 expression on adipose deposition after lymphatic injury. Patients with LE and mice treated with lymphatic excision of the tail had significantly elevated tissue and serum expression of IL-6 and its downstream mediator. The expression of IL-6 was associated with adipose deposition and CD4(+) inflammation and was markedly decreased in CD4KO mice. Loss of IL-6 function resulted in significantly increased adipose deposition after tail lymphatic injury. Our findings suggest that IL-6 is increased as a result of adipose deposition and CD4(+) cell inflammation in lymphedema. In addition, our study suggests that IL-6 expression in lymphedema acts to limit adipose accumulation.
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Affiliation(s)
- Daniel A Cuzzone
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Evan S Weitman
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Nicholas J Albano
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Swapna Ghanta
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ira L Savetsky
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Jason C Gardenier
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Walter J Joseph
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Jeremy S Torrisi
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Jacqueline F Bromberg
- The Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Waldemar L Olszewski
- The Department of Surgical Research and Transplantology, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Stanley G Rockson
- The Department of Medicine, Division of Cardiology, Stanford University Medical Center, Stanford, California
| | - Babak J Mehrara
- The Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York;
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Fenton JI, Hord NG, Ghosh S, Gurzell EA. Immunomodulation by dietary long chain omega-3 fatty acids and the potential for adverse health outcomes. Prostaglandins Leukot Essent Fatty Acids 2013; 89:379-90. [PMID: 24183073 PMCID: PMC3912985 DOI: 10.1016/j.plefa.2013.09.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 09/18/2013] [Accepted: 09/21/2013] [Indexed: 01/07/2023]
Abstract
Recommendations to consume fish for prevention of cardiovascular disease (CVD), along with the U.S. Food and Drug Administration-approved generally recognized as safe (GRAS) status for long chain omega-3 fatty acids, may have had the unanticipated consequence of encouraging long-chain omega-3 (ω-3) fatty acid [(eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] supplementation and fortification practices. While there is evidence supporting a protective role for EPA/DHA supplementation in reducing sudden cardiac events, the safety and efficacy of supplementation with LCω-3PUFA in the context of other disease outcomes is unclear. Recent studies of bacterial, viral, and fungal infections in animal models of infectious disease demonstrate that LCω-3PUFA intake dampens immunity and alters pathogen clearance and can result in reduced survival. The same physiological properties of EPA/DHA that are responsible for the amelioration of inflammation associated with chronic cardiovascular pathology or autoimmune states, may impair pathogen clearance during acute infections by decreasing host resistance or interfere with tumor surveillance resulting in adverse health outcomes. Recent observations that high serum LCω-3PUFA levels are associated with higher risk of prostate cancer and atrial fibrillation raise concern for adverse outcomes. Given the widespread use of supplements and fortification of common food items with LCω-3PUFA, this review focuses on the immunomodulatory effects of the dietary LCω-3PUFAs, EPA and DHA, the mechanistic basis for potential negative health outcomes, and calls for biomarker development and validation as rational first steps towards setting recommended dietary intake levels.
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Affiliation(s)
- Jenifer I Fenton
- Department of Food Science and Human, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, United States; College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48824, United States.
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Lindberg E, Theorell-Haglöw J, Svensson M, Gislason T, Berne C, Janson C. Sleep apnea and glucose metabolism: a long-term follow-up in a community-based sample. Chest 2013; 142:935-942. [PMID: 22499826 DOI: 10.1378/chest.11-1844] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND It has been suggested that sleep-disordered breathing (SDB) is a risk factor for diabetes, but long-term follow-up studies are lacking. The aim of this community-based study was to analyze the influence of SDB on glucose metabolism after > 10 years. METHODS Men without diabetes (N = 141; mean age, 57.5 years) were investigated at baseline, including whole-night respiratory monitoring. After a mean period of 11 years and 4 months, they were followed up with an interview, anthropometric measurements, and blood sampling. Insulin resistance was quantified using the homeostasis model assessment of insulin resistance (HOMA-IR). ΔHOMA-IR was calculated as (HOMA-IR at follow-up − HOMA-IR at baseline). An oral glucose tolerance test was performed on 113 men to calculate the insulin sensitivity index. RESULTS The mean apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) at baseline were 4.7 and 3.3, respectively. At follow-up, 23 men had diabetes. An ODI > 5 was a predictor of developing diabetes (OR, 4.4; 95% CI, 1.1-18.1, after adjusting for age, BMI, and hypertension at baseline and ΔBMI and years with CPAP during follow-up). The ODI was inversely related to the insulin sensitivity index at follow-up (r = −0.27, P = .003). A deterioration in HOMA-IR was significantly related to all variables of SDB (AHI, AHI > 5; ODI, ODI > 5; minimum arterial oxygen saturation), even when adjusting for confounders. When excluding the variable years with CPAP from the multivariate model, all associations weakened. CONCLUSIONS SDB is independently related to the development of insulin resistance and, thereby, the risk of manifest diabetes mellitus.
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Affiliation(s)
- Eva Lindberg
- Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden.
| | - Jenny Theorell-Haglöw
- Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden
| | - Malin Svensson
- Department of Surgical Sciences, Otorhinolaryngology, Uppsala University, Uppsala, Sweden
| | - Thorarinn Gislason
- Department of Respiratory Medicine and Sleep, University Hospital and Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Christian Berne
- Department of Medical Sciences, Internal Medicine, Uppsala University, Uppsala, Sweden
| | - Christer Janson
- Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden
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Utech AE, Tadros EM, Hayes TG, Garcia JM. Predicting survival in cancer patients: the role of cachexia and hormonal, nutritional and inflammatory markers. J Cachexia Sarcopenia Muscle 2012; 3:245-51. [PMID: 22648739 PMCID: PMC3505579 DOI: 10.1007/s13539-012-0075-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/13/2012] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cancer can lead to weight loss, anorexia, and poor nutritional status, which are associated with decreased survival in cancer patients. METHODS Male cancer patients (n = 136) were followed for a mean time of 4.5 years. Variables were obtained at baseline: cancer stage, albumin, hemoglobin, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, bioavailable testosterone, appetite questionnaire, and weight change from baseline to 18 months. Primary statistical tests included Kaplan-Meier survival analysis and Cox proportional hazard regression (PHREG). RESULTS Univariate PHREG showed that cancer stage, albumin, hemoglobin, TNF-α, IL-6, and weight change were each significantly associated with mortality risk (P < 0.05), but bioavailable testosterone was not. Multivariate PHREG analysis established that weight change and albumin were jointly statistically significant even after adjusting for stage. CONCLUSION In this sample of male oncology patients, cancer stage, serum albumin, and weight loss predicted survival. High levels of inflammatory markers and hemoglobin are associated with increased mortality, but do not significantly improve the ability to predict survival above and beyond cancer stage, albumin, and weight loss.
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Affiliation(s)
- Anne E Utech
- Department of Medicine, Michael E. DeBakey Veterans Affairs Medical Center, Baylor College of Medicine, Houston, TX, USA
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Famulla S, Schlich R, Sell H, Eckel J. Differentiation of human adipocytes at physiological oxygen levels results in increased adiponectin secretion and isoproterenol-stimulated lipolysis. Adipocyte 2012; 1:132-181. [PMID: 23700522 PMCID: PMC3609092 DOI: 10.4161/adip.19962] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Adipose tissue (AT) hypoxia occurs in obese humans and mice. Acute hypoxia in adipocytes causes dysregulation of adipokine secretion with an increase in inflammatory factors and diminished adiponectin release. O2 levels in humans range between 3 and 11% revealing that conventional in vitro culturing at ambient air and acute hypoxia treatment (1% O2) are performed under non-physiological conditions. In this study, we mimicked physiological conditions by differentiating human primary adipocytes under 10% or 5% O2 in comparison to 21% O2. Induction of differentiation markers was comparable between all three conditions. Adipokine release by adipocytes differentiated at lower oxygen levels was altered, with a marked upregulation of adiponectin, IL-6 and DPP4 secretion, and reduced leptin levels compared with adipocytes differentiated at 21% O2. Isoproterenol-induced lipolysis was significantly elevated in adipocytes differentiated at 10% and 5% compared with 21% O2. This effect was accompanied by increased protein expression of β-1 and -2 adrenergic receptor, HSL and perilipin. Conditioned medium (CM) of adipocytes differentiated at the three different conditions was generated for stimulation of human skeletal muscle cells (SkMC) or smooth muscle cells (SMC). CM-induced insulin resistance in SkMC was comparable for the different CMs. However, the SMC proliferative effect of CM from adipocytes differentiated at 10% O2 was significantly reduced compared with 21% O2. This study demonstrates that oxygen levels during adipogenesis are important factors altering adipocyte functionality such as adipokine release, in particular adiponectin secretion, as well as the hormone-induced lipolytic pathway.
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31
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Schéle E, Fekete C, Egri P, Füzesi T, Palkovits M, Keller É, Liposits Z, Gereben B, Karlsson-Lindahl L, Shao R, Jansson JO. Interleukin-6 receptor α is co-localised with melanin-concentrating hormone in human and mouse hypothalamus. J Neuroendocrinol 2012; 24:930-43. [PMID: 22295972 DOI: 10.1111/j.1365-2826.2012.02286.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Interleukin (IL)-6 deficient mice develop mature-onset obesity. Furthermore, i.c.v. administration of IL-6 increases energy expenditure, suggesting that IL-6 centrally regulates energy homeostasis. To investigate whether it would be possible for IL-6 to directly influence the energy homeostasis via hypothalamic regulation in humans and rodents, we mapped the distribution of the ligand binding IL-6 receptor α (IL-6Rα) in this brain region. In the human hypothalamus, IL-6Rα-immunoreactivity was detected in perikarya and first-order dendrites of neurones. The IL-6Rα-immunoreactive (-IR) neurones were observed posterior to the level of the interventricular foramen. There, IL-6Rα-IR neurones were located in the lateral hypothalamic, perifornical, dorsal and posterior hypothalamic areas, the hypothalamic dorsomedial nucleus and in the zona incerta. In the caudal part of the hypothalamus, the density of the IL-6Rα-IR neurones gradually increased. Double-labelling immunofluorescent studies demonstrated that IL-6Rα immunoreactivity was localised in the same neurones as the orexigenic neuropeptide, melanin-concentrating hormone (MCH). By contrast, IL-6Rα-immunoreactivity was not observed in the orexin B-IR neurones. To determine whether the observed expression of IL-6Rα is evolutionary conserved, we studied the co-localisation of IL-6Rα with MCH and orexin in the mouse hypothalamus, where IL-6Rα-immunoreactivity was present in numerous MCH-IR and orexin-IR neurones. Our data demonstrate that the MCH neurones of the human hypothalamus, as well as the MCH and orexin neurones of the mouse hypothalamus, contain IL-6Rα. This opens up the possibility that IL-6 influences the energy balance through the MCH neurones in humans, and both MCH and orexin neurones in mice.
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Affiliation(s)
- E Schéle
- Institute of Neuroscience and Physiology/Endocrinology, The Sahlgrenska Academy at Gothenburg University, Gothenburg, Sweden
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Thompson D, Karpe F, Lafontan M, Frayn K. Physical activity and exercise in the regulation of human adipose tissue physiology. Physiol Rev 2012; 92:157-91. [PMID: 22298655 DOI: 10.1152/physrev.00012.2011] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Physical activity and exercise are key components of energy expenditure and therefore of energy balance. Changes in energy balance alter fat mass. It is therefore reasonable to ask: What are the links between physical activity and adipose tissue function? There are many complexities. Physical activity is a multifaceted behavior of which exercise is just one component. Physical activity influences adipose tissue both acutely and in the longer term. A single bout of exercise stimulates adipose tissue blood flow and fat mobilization, resulting in delivery of fatty acids to skeletal muscles at a rate well-matched to metabolic requirements, except perhaps in vigorous intensity exercise. The stimuli include adrenergic and other circulating factors. There is a period following an exercise bout when fatty acids are directed away from adipose tissue to other tissues such as skeletal muscle, reducing dietary fat storage in adipose. With chronic exercise (training), there are changes in adipose tissue physiology, particularly an enhanced fat mobilization during acute exercise. It is difficult, however, to distinguish chronic "structural" changes from those associated with the last exercise bout. In addition, it is difficult to distinguish between the effects of training per se and negative energy balance. Epidemiological observations support the idea that physically active people have relatively low fat mass, and intervention studies tend to show that exercise training reduces fat mass. A much-discussed effect of exercise versus calorie restriction in preferentially reducing visceral fat is not borne out by meta-analyses. We conclude that, in addition to the regulation of fat mass, physical activity may contribute to metabolic health through beneficial dynamic changes within adipose tissue in response to each activity bout.
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Tussing-Humphreys L, Frayn KN, Smith SR, Westerman M, Dennis AL, Nemeth E, Thomson J, Pusatcioglu C. Subcutaneous adipose tissue from obese and lean adults does not release hepcidin in vivo. ScientificWorldJournal 2011; 11:2197-206. [PMID: 22125467 PMCID: PMC3217603 DOI: 10.1100/2011/634861] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/23/2011] [Indexed: 01/04/2023] Open
Abstract
Hepcidin is the main regulator of systemic iron homeostasis and is primarily produced by the liver but is also expressed, at the mRNA-level, in periphery tissues including the subcutaneous and visceral adipose tissue. Obesity is associated with elevated hepcidin concentrations and iron depletion suggesting that the exaggerated fat mass in obesity could contribute significantly to circulating hepcidin levels consequently altering iron homeostasis. The objective of this study was to determine if abdominal subcutaneous adipose tissue (AbScAT) releases hepcidin in vivo and if release is modified by obesity. Arterio-venous differences in concentrations of hepcidin were measured across AbScAT in 9 obese and 9 lean adults. Overall (n = 18), mean plasma hepcidin concentrations were significantly higher in arterialized compared to AbScAT venous samples [mean difference (arterialized-AbScAT venous plasma hepcidin) = 4.9 ± 9.6 ng/mL, P = 0.04]. Net regional release was not calculated because mean venous plasma hepcidin concentrations were lower than mean arterialized concentrations indicating no net release. Significant correlations between AbScAT venous and arterialized plasma hepcidin concentrations with anthropometric variables were not observed. Findings from this vein drainage study suggest there is no net release of hepcidin from the AbScAT depot and thereby no ability to signal systemically, even in obesity.
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Affiliation(s)
- Lisa Tussing-Humphreys
- USDA Agricultural Research Service, Louisiana State University AgCenter, Knapp Hall, Baton Rouge, LA 70803, USA.
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Højbjerre L, Alibegovic AC, Sonne MP, Dela F, Vaag A, Bruun JM, Stallknecht B. Increased lipolysis but diminished gene expression of lipases in subcutaneous adipose tissue of healthy young males with intrauterine growth retardation. J Appl Physiol (1985) 2011; 111:1863-70. [PMID: 21903886 DOI: 10.1152/japplphysiol.00960.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intrauterine growth retardation (IUGR) is associated with a central fat distribution and risk of developing type 2 diabetes in adults when exposed to a sedentary Western lifestyle. Increased lipolysis is an early defect of metabolism in IUGR subjects, but the sites and molecular mechanisms involved are unknown. Twenty IUGR and 20 control (CON) subjects, aged 20-30 years, were studied before and after 10 days of bed rest using the glucose clamp technique combined with measurements of in vivo metabolism by microdialysis technique and blood flow by (133)Xe washout technique in subcutaneous abdominal (SCAAT) and femoral (SCFAT) adipose tissue. Additionally, mRNA expression of lipases was evaluated in biopsies from SCAAT. Lipolysis in SCAAT was substantially higher in IUGR than in CON subjects despite markedly lower mRNA expression of lipases. Blood flow was higher in IUGR compared with CON in both SCAAT and SCFAT. Whole body insulin sensitivity did not differ between groups and decreased after bed rest. After bed rest, SCAAT lipolysis remained higher in IUGR compared with CON, and SCFAT lipolysis decreased in CON but not in IUGR. Prior to the development of whole body insulin resistance, young men with IUGR are characterized by increased in vivo adipose tissue lipolysis and blood flow with a paradoxically decreased expression of lipases compared with CON, and 10 days of physical inactivity underlined the baseline findings. Subjects with IUGR exhibit primary defects in adipose tissue metabolism.
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Affiliation(s)
- Lise Højbjerre
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
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White UA, Stephens JM. The gp130 receptor cytokine family: regulators of adipocyte development and function. Curr Pharm Des 2011; 17:340-6. [PMID: 21375496 DOI: 10.2174/138161211795164202] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 02/10/2011] [Indexed: 01/04/2023]
Abstract
Gp130 cytokines are involved in the regulation of numerous biological processes, including hematopoiesis, immune response, inflammation, cardiovascular action, and neuronal survival. These cytokines share glycoprotein 130 as a common signal transducer in their receptor complex and typically activate STAT3. Most gp130 cytokines have paracrine or endocrine actions, and their levels can be measured in circulation in rodents and humans. In recent years, various laboratories have conducted studies to demonstrate that gp130 cytokines can modulate adipocyte development and function. Therefore, these studies suggest that some gp130 cytokines may be viable anti-obesity therapeutics. In this review, we will summarize the reported effects of gp130 cytokines on adipocyte differentiation and adipocyte function. In addition, the modulation of gp130 cytokines in conditions of obesity, insulin resistance, and Type 2 diabetes will be presented.
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Affiliation(s)
- Ursula A White
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
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Torres-Leal FL, Fonseca-Alaniz MH, Rogero MM, Tirapegui J. The role of inflamed adipose tissue in the insulin resistance. Cell Biochem Funct 2010; 28:623-31. [DOI: 10.1002/cbf.1706] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Wolsk E, Mygind H, Grøndahl TS, Pedersen BK, van Hall G. IL-6 selectively stimulates fat metabolism in human skeletal muscle. Am J Physiol Endocrinol Metab 2010; 299:E832-40. [PMID: 20823453 DOI: 10.1152/ajpendo.00328.2010] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Interleukin (IL)-6 is chronically elevated in type 2 diabetes but also during exercise. However, the exact metabolic role, and hence the physiological significance, has not been elucidated. The objective of this study was to investigate the in vivo effect of recombinant human (rh) IL-6 on human fat and glucose metabolism and signaling of both adipose tissue and skeletal muscle. Eight healthy postabsorptive males were infused with either rhIL-6 or saline for 4 h, eliciting IL-6 levels of ∼40 and ∼1 pg/ml, respectively. Systemic, skeletal muscle, and adipose tissue fat and glucose metabolism was assessed before, during, and 2 h after cessation of the infusion. Glucose metabolism was unaffected by rhIL-6. In contrast, rhIL-6 increased systemic fatty acid oxidation approximately twofold after 60 min, and it remained elevated even 2 h after the infusion. The increase in oxidation was followed by an increase in systemic lipolysis. Adipose tissue lipolysis and fatty acid kinetics were unchanged with rhIL-6 compared with saline infusion. Conversely, rhIL-6 infusion caused an increase in skeletal muscle unidirectional fatty acid and glycerol release, indicative of an increase in lipolysis. The increased lipolysis in muscle could account for the systemic changes. Skeletal muscle signaling increased after 1 h of rhIL-6 infusion, indicated by a fourfold increase in the phosphorylated signal transducer and activator of transcription (STAT) 3-to-STAT3 ratio, whereas no changes in phosphorylated AMP-activated protein kinase or acetyl-CoA carboxylase levels could be observed. Our findings suggest that an acute increase in IL-6 at a normophysiological level selectively stimulates lipolysis in skeletal muscle, whereas adipose tissue is unaffected.
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Affiliation(s)
- Emil Wolsk
- The Centre of Inflammation and Metabolism, Department of Infectious Diseases, University of Copenhagen, Denmark.
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Mathieu P, Lemieux I, Després JP. Obesity, inflammation, and cardiovascular risk. Clin Pharmacol Ther 2010; 87:407-16. [PMID: 20200516 DOI: 10.1038/clpt.2009.311] [Citation(s) in RCA: 298] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Obesity, a highly prevalent condition, is heterogeneous with regard to its impact on cardiovascular disease (CVD) risk. Epidemiological observations and metabolic investigations have consistently demonstrated that the accumulation of excess visceral fat is related to an increased risk of CVD as well as several metabolic and inflammatory perturbations. In the past decade, data from several studies have served to emphasize that atherosclerosis has an inflammatory component that may contribute to several key pathophysiological processes. Study data have also highlighted the finding that the expanded visceral fat is infiltrated by macrophages that conduct "cross-talk" with adipose tissue through several significant mechanisms. In this review, we provide, in the context of CVD risk, an up-to-date account of the complex interactions that occur between a dysfunctional adipose tissue phenotype and inflammation.
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Affiliation(s)
- P Mathieu
- Quebec Heart and Lung Institute/Research Center, Québec, Québec, Canada.
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Billeter A, Turina M, Seifert B, Mica L, Stocker R, Keel M. Early serum procalcitonin, interleukin-6, and 24-hour lactate clearance: useful indicators of septic infections in severely traumatized patients. World J Surg 2010; 33:558-66. [PMID: 19148699 DOI: 10.1007/s00268-008-9896-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Elevated lactate and interleukin-6 (IL-6) levels were shown to correlate with mortality and multiple organ dysfunction in severely traumatized patients. The purpose of this study was to test whether an association exists between 24-hour lactate clearance, IL-6 and procalcitonin (PCT) levels, and the development of infectious complications in trauma patients. METHODS A total of 1757 consecutive trauma patients with an Injury Severity Score (ISS) > 16 admitted over a 10-year period were retrospectively analyzed over a 21-day period. Exclusion criteria included death within 72 h of admission (24.5%), late admission > 12 h after injury (16%), and age < 16 years (0.5%). Data are stated as the median (range). RESULTS Altogether, 1032 trauma patients (76.2% male) with an average age of 38 years, a median ISS of 29 (16-75), and an Acute Physiology, Age, and Chronic Health Evaluation (APACHE) II score of 14 (0-40) were evaluated. The in-hospital mortality (>3 days) was 10%. Patients with insufficient 24-hour lactate clearance had a high rate of overall mortality and infections. Elevated early serum procalcitonin on days 1 to 5 after trauma was strongly associated with the subsequent development of sepsis (p < 0.01) but not with nonseptic infections. The kinetics of IL-6 were similar to those of PCT but did differentiate between infected and noninfected patients after day 5. CONCLUSIONS This study demonstrates that elevated early procalcitonin and IL-6 levels and inadequate 24-hour lactate clearance help identify trauma patients who develop septic and nonseptic infectious complications. Definition of specific cutoff values and early monitoring of these parameters may help direct early surgical and antibiotic therapy and reduce infectious mortality.
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Affiliation(s)
- Adrian Billeter
- Division of Trauma Surgery, Department of Surgery, University of Zürich Hospital, Rämistrasse 100, Zurich CH-8091, Switzerland.
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Benrick A, Schéle E, Pinnock SB, Wernstedt-Asterholm I, Dickson SL, Karlsson-Lindahl L, Jansson JO. Interleukin-6 gene knockout influences energy balance regulating peptides in the hypothalamic paraventricular and supraoptic nuclei. J Neuroendocrinol 2009; 21:620-8. [PMID: 19490366 DOI: 10.1111/j.1365-2826.2009.01879.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Interleukin (IL)-6 is a pro-inflammatory cytokine that also affects metabolic function because IL-6 depleted (IL-6(-/-)) mice develop late-onset obesity. IL-6 appears to act in the central nervous system, presumably in the hypothalamus, to increase energy expenditure that appears to involve stimulation of the sympathetic nervous system. In the present study, we explored possible central mechanisms for the effects exerted by IL-6 on body fat. Therefore, we measured the effects of IL-6 depletion in IL-6(-/-) mice on expression of key hypothalamic peptide genes involved in energy balance by the real time polymerase chain reaction. Additionally, co-localisation between such peptides and IL-6 receptor alpha was investigated by immunohistochemistry. IL-6 deficiency decreased the expression of several peptides found in the paraventricular nucleus (PVN), which is a nucleus that has been attributed an adipostatic function. For example, corticotrophin-releasing hormone (CRH), which is reported to stimulate the sympathetic nervous system, was decreased by 40% in older IL-6(-/-) mice. Oxytocin, which is reported to prevent obesity, was also decreased in older IL-6(-/-) animals, as was arginine vasopressin (AVP). The IL-6 receptor alpha was abundantly expressed in the PVN, but also in the supraoptic nucleus, and was shown to be co-expressed to a high extent with CRH, AVP, oxytocin and thyrotrophin-releasing hormone. These data indicate that depletion of endogenous IL-6, a body fat suppressing cytokine, is associated with the decreased expression of CRH and oxytocin (i.e. energy balance regulating peptides) as well as AVP in the PVN. Because IL-6 receptor alpha is co-expressed with CRH, oxytocin and AVP, IL-6 could stimulate the expression of these peptides directly.
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Affiliation(s)
- A Benrick
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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Abstract
In the past few years, several interleukins (ILs) attracted considerable attention as potential effectors in the pathology and physiology of insulin resistance associated with type 2 diabetes mellitus (T2DM) and obesity. IL-1, a major proinflammatory cytokine, is present at increased levels in patients with diabetes mellitus, and could promote beta-cell destruction and alter insulin sensitivity. The effects of IL-1 are likely to be counteracted by IL-1 receptor antagonist protein (IL-1ra), as suggested by interventional studies in patients with T2DM who were treated with a recombinant form of this protein. However, studies in IL-1ra-deficient mice provided controversial results on the exact effect of the IL-1 signaling pathway on insulin secretion, insulin sensitivity and accumulation of adipose tissue. Likewise, IL-6 has been suggested to be involved in the development of obesity-related and T2DM-related insulin resistance. The action of IL-6 on glucose homeostasis is also complex and integrates central and peripheral mechanisms. Both experimental and clinical studies now converge to show that several ILs contribute to the pathology and physiology of T2DM through their interaction with insulin signaling pathways and beta-cell function.
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Affiliation(s)
- Bruno Fève
- Faculté de Médecine Paris-sud, Université Paris 11, Le Kremlin-Bicêtre, France.
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Bragt MCE, Plat J, Mensink M, Schrauwen P, Mensink RP. Anti-inflammatory effect of rosiglitazone is not reflected in expression of NFkappaB-related genes in peripheral blood mononuclear cells of patients with type 2 diabetes mellitus. BMC Endocr Disord 2009; 9:8. [PMID: 19243600 PMCID: PMC2653037 DOI: 10.1186/1472-6823-9-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 02/25/2009] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Rosiglitazone not only improves insulin-sensitivity, but also exerts anti-inflammatory effects. We have now examined in type 2 diabetic patients if these effects are reflected by changes in mRNA expression in peripheral blood mononuclear cells (PBMCs) to see if these cells can be used to study these anti-inflammatory effects at the molecular level in vivo. METHOD Eleven obese type 2 diabetic patients received rosiglitazone (2 x 4 mg/d) for 8 weeks. Fasting blood samples were obtained before and after treatment. Ten obese control subjects served as reference group. The expression of NFkappaB-related genes and PPARgamma target genes in PBMCs, plasma TNFalpha, IL6, MCP1 and hsCRP concentrations were measured. In addition, blood samples were obtained after a hyperinsulinemic-euglycemic clamp. RESULTS Rosiglitazone reduced plasma MCP1 and hsCRP concentrations in diabetic patients (-9.5 +/- 5.3 pg/mL, p = 0.043 and -1.1 +/- 0.3 mg/L p = 0.003), respectively). For hsCRP, the concentration became comparable with the non-diabetic reference group. However, of the 84 NFkappaB-related genes that were measured in PBMCs from type 2 diabetic subjects, only RELA, SLC20A1, INFgamma and IL1R1 changed significantly (p < 0.05). In addition, PPARgamma and its target genes (CD36 and LPL) did not change. During the clamp, insulin reduced plasma MCP1 concentration in the diabetic and reference groups (-9.1 +/- 1.8%, p = 0.001 and -11.1 +/- 4.1%, p = 0.023, respectively) and increased IL6 concentration in the reference group only (23.5 +/- 9.0%, p = 0.028). CONCLUSION In type 2 diabetic patients, the anti-inflammatory effect of rosiglitazone is not reflected by changes in NFkappaB and PPARgamma target genes in PBMCs in vivo. Furthermore, our results do not support that high insulin concentrations contribute to the pro-inflammatory profile in type 2 diabetic patients.
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Affiliation(s)
- Marjolijn CE Bragt
- Nutrigenomics Consortium, Top Institute Food and Nutrition, PO BOX 557, 6700 AN Wageningen, The Netherlands
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Jogchum Plat
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Marco Mensink
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Patrick Schrauwen
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Ronald P Mensink
- Nutrigenomics Consortium, Top Institute Food and Nutrition, PO BOX 557, 6700 AN Wageningen, The Netherlands
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, The Netherlands
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Huth C, Illig T, Herder C, Gieger C, Grallert H, Vollmert C, Rathmann W, Hamid YH, Pedersen O, Hansen T, Thorand B, Meisinger C, Doring A, Klopp N, Gohlke H, Lieb W, Hengstenberg C, Lyssenko V, Groop L, Ireland H, Stephens JW, Wernstedt Asterholm I, Jansson JO, Boeing H, Mohlig M, Stringham HM, Boehnke M, Tuomilehto J, Fernandez-Real JM, Lopez-Bermejo A, Gallart L, Vendrell J, Humphries SE, Kronenberg F, Wichmann HE, Heid IM. Joint analysis of individual participants' data from 17 studies on the association of the IL6 variant -174G>C with circulating glucose levels, interleukin-6 levels, and body mass index. Ann Med 2009; 41:128-38. [PMID: 18752089 PMCID: PMC3801210 DOI: 10.1080/07853890802337037] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Several studies have investigated associations between the -174G>C single nucleotide polymorphism (rs1800795) of the IL6 gene and phenotypes related to type 2 diabetes mellitus (T2DM) but presented inconsistent results. AIMS This joint analysis aimed to clarify whether IL6 -174G>C was associated with glucose and circulating interleukin-6 concentrations as well as body mass index (BMI). METHODS Individual-level data from all studies of the IL6-T2DM consortium on Caucasian subjects with available BMI were collected. As study-specific estimates did not show heterogeneity (P>0.1), they were combined by using the inverse-variance fixed-effect model. RESULTS The main analysis included 9440, 7398, 24,117, or 5659 non-diabetic and manifest T2DM subjects for fasting glucose, 2-hour glucose, BMI, or circulating interleukin-6 levels, respectively. IL6 -174 C-allele carriers had significantly lower fasting glucose (-0.091 mmol/L, P=0.014). There was no evidence for association between IL6 -174G>C and BMI or interleukin-6 levels, except in some subgroups. CONCLUSIONS Our data suggest that C-allele carriers of the IL6 -174G>C polymorphism have lower fasting glucose levels on average, which substantiates previous findings of decreased T2DM risk of these subjects.
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Affiliation(s)
- Cornelia Huth
- Institute of Epidemiology, Helmholtz Zentrum Munchen, Neuherberg, Germany
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Ropelle ER, Fernandes MFA, Flores MBS, Ueno M, Rocco S, Marin R, Cintra DE, Velloso LA, Franchini KG, Saad MJA, Carvalheira JBC. Central exercise action increases the AMPK and mTOR response to leptin. PLoS One 2008; 3:e3856. [PMID: 19052642 PMCID: PMC2585815 DOI: 10.1371/journal.pone.0003856] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 11/06/2008] [Indexed: 11/19/2022] Open
Abstract
AMP-activated protein kinase (AMPK) and mammalian Target of Rapamycin (mTOR) are key regulators of cellular energy balance and of the effects of leptin on food intake. Acute exercise is associated with increased sensitivity to the effects of leptin on food intake in an IL-6-dependent manner. To determine whether exercise ameliorates the AMPK and mTOR response to leptin in the hypothalamus in an IL-6-dependent manner, rats performed two 3-h exercise bouts, separated by one 45-min rest period. Intracerebroventricular IL-6 infusion reduced food intake and pretreatment with AMPK activators and mTOR inhibitor prevented IL-6-induced anorexia. Activators of AMPK and fasting increased food intake in control rats to a greater extent than that observed in exercised ones, whereas inhibitor of AMPK had the opposite effect. Furthermore, the reduction of AMPK and ACC phosphorylation and increase in phosphorylation of proteins involved in mTOR signal transduction, observed in the hypothalamus after leptin infusion, were more pronounced in both lean and diet-induced obesity rats after acute exercise. Treatment with leptin reduced food intake in exercised rats that were pretreated with vehicle, although no increase in responsiveness to leptin-induced anorexia after pretreatment with anti-IL6 antibody, AICAR or Rapamycin was detected. Thus, the effects of leptin on the AMPK/mTOR pathway, potentiated by acute exercise, may contribute to appetite suppressive actions in the hypothalamus.
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Affiliation(s)
- Eduardo R. Ropelle
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | - Marcelo B. S. Flores
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Mirian Ueno
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Silvana Rocco
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Rodrigo Marin
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Dennys E. Cintra
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Lício A. Velloso
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Kleber G. Franchini
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Mario J. A. Saad
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - José B. C. Carvalheira
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- * E-mail:
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Franckhauser S, Elias I, Rotter Sopasakis V, Ferré T, Nagaev I, Andersson CX, Agudo J, Ruberte J, Bosch F, Smith U. Overexpression of Il6 leads to hyperinsulinaemia, liver inflammation and reduced body weight in mice. Diabetologia 2008; 51:1306-16. [PMID: 18437347 DOI: 10.1007/s00125-008-0998-8] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 02/21/2008] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS IL-6 is released by the adipose tissue and increased circulating levels in obesity are associated with hyperinsulinaemia and insulin resistance. Short-term experiments suggest that increased IL-6 release by the skeletal muscle following exercise may improve insulin sensitivity. METHODS In order to examine the effect of chronically elevated IL-6 levels, we overexpressed Il6 in skeletal muscle in mice using an electro-transfer procedure. RESULTS Circulating IL-6 levels were increased and the animals rapidly lost both weight and body fat, but food intake was unchanged, which is consistent with the finding that IL-6 increased energy expenditure. Insulin levels were inappropriately elevated and combined with hypoglycaemia in spite of reduced 2-deoxy-D: -glucose uptake by skeletal muscle. Insulin-stimulated glucose uptake by skeletal muscles ex vivo was reduced, probably due to the decreased amounts of glucose transporter (GLUT)-4. Beta cell insulin content was increased, while apparent beta cell mass was unchanged. Circulating serum amyloid A cluster levels were increased tenfold due to a pronounced proinflammatory state in the liver with infiltration of inflammatory cells. However, no liver steatosis was found, which may be accounted for by concomitant AMP kinase activation. CONCLUSIONS/INTERPRETATION Chronically elevated IL-6 levels lead to inappropriate hyperinsulinaemia, reduced body weight, impaired insulin-stimulated glucose uptake by the skeletal muscles and marked inflammation in the liver. Thus, the pleiotrophic effects of chronically elevated IL-6 levels preclude any obvious usefulness in treating obesity or its associated metabolic complications in man, despite the fact that weight reduction may be expected.
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Affiliation(s)
- S Franckhauser
- Center of Animal Biotechnology and Gene Therapy, Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra CIBERDEM-ISCIII, Spain
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Cartier A, Lemieux I, Alméras N, Tremblay A, Bergeron J, Després JP. Visceral obesity and plasma glucose-insulin homeostasis: contributions of interleukin-6 and tumor necrosis factor-alpha in men. J Clin Endocrinol Metab 2008; 93:1931-8. [PMID: 18319319 DOI: 10.1210/jc.2007-2191] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE This study examined the relationships of two inflammatory cytokines, IL-6 and TNF-alpha, to visceral adiposity and indices of plasma glucose-insulin homeostasis. RESEARCH DESIGN AND METHODS Plasma levels of IL-6 and TNF-alpha were measured in 189 untreated asymptomatic men (aged 43.7 +/- 7.8 yr; body mass index 29.0 +/- 4.3 kg/m(2); waist girth 98.6 +/- 10.3 cm). RESULTS Significant and positive associations were found between both cytokines with adiposity and adipose tissue distribution indices (0.15 < or = r < 0.32; P < 0.05) as well as plasma glucose-insulin homeostasis variables (0.22 < or = r < 0.28; P <0.05). Comparison of two subgroups, each composed of 32 overweight men (> or =25 kg/m(2)) with similar body mass index values (28.7 kg/m(2) in both groups) but with markedly different levels of visceral adipose tissue (< vs. > or = 130 cm(2)), revealed significant differences only for IL-6 levels (1.42 +/- 1.15 vs. 0.86 +/- 0.52 pg/ml; P < 0.02 for men with high vs. low visceral adipose tissue, respectively). Finally, when subjects were stratified on the basis of their respective concentrations of IL-6 and TNF-alpha (using the 50th percentile of their overall distribution), an ANOVA revealed an independent contribution of IL-6 to the variation of fasting insulin (P < 0.01) and each of these two cytokines to the variation of insulin levels measured after a 75-g oral glucose challenge (P <0.01 for IL-6 and P < 0.05 for TNF-alpha). CONCLUSIONS Because IL-6 appeared to be clearly associated with visceral adiposity, TNF-alpha rather showed associations with indices of total body fatness. Thus, TNF-alpha may contribute to the insulin resistance of overall obesity, whereas IL-6 may be one of the mediators of the hyperinsulinemic state specifically related to excess visceral adiposity.
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Affiliation(s)
- Amélie Cartier
- Québec Heart Institute, Hôpital Laval Research Centre, Hôpital Laval, 2725 Chemin Sainte-Foy, Pavilion Marguerite-D'Youville, Québec, Canada
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47
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Cernkovich ER, Deng J, Bond MC, Combs TP, Harp JB. Adipose-specific disruption of signal transducer and activator of transcription 3 increases body weight and adiposity. Endocrinology 2008; 149:1581-90. [PMID: 18096662 PMCID: PMC2276706 DOI: 10.1210/en.2007-1148] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To determine the role of STAT3 in adipose tissue, we used Cre-loxP DNA recombination to create mice with an adipocyte-specific disruption of the STAT3 gene (ASKO mice). aP2-Cre-driven disappearance of STAT3 expression occurred on d 6 of adipogenesis, a time point when preadipocytes have already undergone conversion to adipocytes. Thus, this knockout model examined the role of STAT3 in mature but not differentiating adipocytes. Beginning at 9 wk of age, ASKO mice weighed more than their littermate controls and had increased adipose tissue mass, associated with adipocyte hypertrophy, but not adipocyte hyperplasia, hyperphagia, or reduced energy expenditure. Leptin-induced, but not isoproterenol-induced, lipolysis was impaired in ASKO adipocytes, which may partially explain the increased cell size. Despite reduced adiponectin and increased liver triacylglycerol, ASKO mice displayed normal glucose tolerance. Overall, these findings demonstrate that adipocyte STAT3 regulates body weight homeostasis in part through direct effects of leptin on adipocytes.
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Affiliation(s)
- Erin R Cernkovich
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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48
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Abstract
Interleukin-6 (IL-6) is a central player in the regulation of inflammation, haematopoiesis, immune response and host defense mechanisms. During the last decade, an accumulating amount of data suggested a pivotal role for IL-6 in metabolic processes, thus fortifying the picture of IL-6 as a multifaceted, pleiotropic cytokine. Because of its secretion by adipose tissue and contracting skeletal muscle and its broad action on central and peripheral organs, IL-6 has been termed an adipokine and a myokine. Its quantitative release from adipose tissue results in a subclinical, systemic elevation of IL-6 plasma levels with increasing body fat content, which may be implicated in the proinflammatory state leading to insulin resistance. On the other hand, IL-6 produced in the working muscle during physical activity could act as an energy sensor by activating AMP-activated kinase and enhancing glucose disposal, lipolysis and fat oxidation. In addition, both impaired IL-6 secretion and action are risk factors for weight gain. Thus, IL-6 clearly has lipolytic effects and anti-obesity potential. However, the application of IL-6 itself is at least limited by a narrow therapeutic range and its important function for a balanced inflammatory response. Further studies on the molecular basis of the metabolic effects of IL-6 could elucidate novel therapeutic strategies for custom-designed, IL-6-related substances.
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Affiliation(s)
- M Hoene
- Department of Internal Medicine, Division of Endocrinology, Metabolism, Nephrology, Angiology, Pathobiochemistry and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
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49
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Abstract
Derangements in whole body glucose and lipid metabolism, accompanied by insulin resistance, are key features of obesity and the metabolic syndrome. A role for inflammation as a causative factor is an emerging concept in the field of metabolic disease. Research has centred on identifying important inflammatory markers, and tumour necrosis factor-alpha has been highlighted as a key mediator of insulin resistance, as well as interleukin-6 (IL-6). A parallel ongoing endeavour is the unravelling of molecular mechanisms underlying the beneficial effects of physical exercise on whole body glucose and lipid metabolism. Release of IL-6 from the contracting skeletal muscle has been proposed to be one of the molecular signals promoting the beneficial exercise-induced effects. These two opposing views of IL-6 underscore that the role of IL-6 in whole body physiology is incompletely resolved. This review aims at summarizing the current data on mechanisms by which IL-6 may impact on glucose and lipid metabolism.
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Affiliation(s)
- S Glund
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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50
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Garcia JM, Polvino WJ. Effect on body weight and safety of RC-1291, a novel, orally available ghrelin mimetic and growth hormone secretagogue: results of a phase I, randomized, placebo-controlled, multiple-dose study in healthy volunteers. Oncologist 2007; 12:594-600. [PMID: 17522248 DOI: 10.1634/theoncologist.12-5-594] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
PURPOSE RC-1291 is a novel, oral ghrelin mimetic and growth hormone (GH) secretagogue being developed to increase appetite and lean muscle mass in patients with cancer-associated anorexia/cachexia. This randomized, double-blind, placebo-controlled, multiple-dose, dose-escalation phase I study in healthy volunteers evaluated RC-1291 once daily (qd) and twice daily (bid) for effect on body weight and safety. METHODS The study was conducted with three sequential groups of volunteers. Panel A subjects (n = 8) received placebo or RC-1291, 25 mg qd, for 5 days. Panel B subjects received RC-1291, 25 mg bid or 50 mg qd, for 6 days then crossed over to the other dosage for 5 days (n = 12); three subjects received placebo for all 11 doses to maintain double-blinding. Panel C subjects (n = 9) received placebo or RC-1291, 75 mg qd, for 6 days. RESULTS Subjects who received RC-1291, 50 or 75 mg, had significant dose-related weight gain after 6 days versus placebo, with the greatest increases seen with daily dosing. The mean increase in weight from baseline after 50 mg qd was 1.25 +/- 0.725 kg (p = .0022 versus placebo), and after 75 mg qd it was 1.16 +/- 0.651 kg (p = .0022 versus placebo). One subject in the 50 mg qd group had moderate transient elevation in aspartate aminotransferase and alanine aminotransferase levels. No other laboratory or clinical adverse events of consequence were reported. CONCLUSIONS Results indicate that RC-1291 produces dose-related increases in body weight with no dose-limiting adverse effects, and may be an effective treatment for anorexia/cachexia.
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Affiliation(s)
- Jose M Garcia
- Michael E. DeBakey Veterans Affairs Medical Center, Baylor College of Medicine, Houston, Texas 77030, USA.
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