1
|
Pathophysiology of obesity and its associated diseases. Acta Pharm Sin B 2023. [DOI: 10.1016/j.apsb.2023.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
2
|
Tian J, Wang T, Jia K, Guo L, Swerdlow RH, Du H. Nonobese Male Patients with Alzheimer's Disease Are Vulnerable to Decrease in Plasma Leptin. J Alzheimers Dis 2022; 88:1017-1027. [PMID: 35723107 PMCID: PMC9553411 DOI: 10.3233/jad-220447] [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] [Indexed: 11/15/2022]
Abstract
BACKGROUND Metabolic dysfunction links to cognitive deficits in Alzheimer's disease (AD). Leptin is an anti-obesity hormone that modulates energy homeostasis and memory function. Although leptin deregulation is implicated in mouse models of AD-like brain pathology, clinical studies have shown inconsistent results regarding an association of leptin with the development of this neurodegenerative disorder. OBJECTIVE We investigated the changes of plasma leptin and the correlation of sex-stratified circulating leptin with cognitive performance, AD-related biological markers, and metabolic status in patients with AD and cognitively unimpaired (CU) counterparts. METHODS We used nonobese AD patients and CU controls in a University of Kansas Medical Center (KUMC) cohort. Plasma leptin levels, circulating AD-related molecules and metabolic profiles were examined and analyzed. RESULTS In contrast to unchanged circulating leptin in females, male patients exhibited decreased plasma leptin levels compared with male CU counterparts. Moreover, plasma leptin showed no correlation with cognitive performance and AD blood biomarkers in patients with either sex. Of note, females but not males demonstrated an association of plasma leptin with body mass index, high density lipoprotein-cholesterol and its ratio with total cholesterol and triglycerides. CONCLUSION Our findings suggest that leptin deficiency is associated with nonobese male AD patients, supporting systemic dysmetabolism in the development of this neurodegenerative disorder in certain populations. Although plasma leptin may have limited capacity to reflect disease severity or progression, future mechanistic studies on the regulation of leptin in nonobese patients with AD would deepen our understanding of the sex-related disparity of AD etiopathogenesis.
Collapse
Affiliation(s)
- Jing Tian
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | - Tienju Wang
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | - Kun Jia
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | - Lan Guo
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, USA
| | - Russell H. Swerdlow
- Department of Neurology, Alzheimer’s Disease Center, University of Kansas Medical Center, Lawrence, KS, USA
| | - Heng Du
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, USA
- Department of Neurology, Alzheimer’s Disease Center, University of Kansas Medical Center, Lawrence, KS, USA
| |
Collapse
|
3
|
Relationship between Physical Activity and the Metabolic, Inflammatory Axis in Pregnant Participants. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182413160. [PMID: 34948770 PMCID: PMC8701987 DOI: 10.3390/ijerph182413160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 01/26/2023]
Abstract
Physical activity (PA) during pregnancy is beneficial for mother and child. Little is known regarding the effects of PA on specific adipokines/myokines and their impact during pregnancy. This study investigates the correlation between PA during late pregnancy, body composition, and maternal levels of leptin, IL-6, and TNF-α at delivery. In a cross-sectional study of 91 pregnant participants (mean age 33.9 ± 4.6 years) without gestational diabetes mellitus or preeclampsia, anthropometric data and blood samples were taken at delivery. PA during the third trimester was measured via the Pregnancy Physical Activity Questionnaire. Activities were ranked by intensity: sedentary (<1.5 metabolic equivalent (METs)), light (1.5–3.0 METs), moderate (3.0–6.0 METs), and vigorous activity (>6.0 METs). Leptin at delivery correlated positively with body composition and negatively with light PA intensity. Sedentary behaviour showed a positive correlation with IL-6 levels at delivery. Moderate activity during the last trimester, sedentary activity levels, and body composition had the greatest influence on maternal IL-6 at delivery. Completed weeks of pregnancy, moderate and light PA, and sedentary activity had the greatest influence on maternal TNF-α at delivery. PA during late pregnancy potentially affects circulating (adipo-)/myokines. Further studies are needed to examine causal relationships and the impact on maternal and new-born health.
Collapse
|
4
|
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).
Collapse
|
5
|
Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
Collapse
Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
| |
Collapse
|
6
|
Xu F, Cao H, Chen Z, Gu H, Guo W, Lin B, Weng J. Short-term GLP-1 receptor agonist exenatide ameliorates intramyocellular lipid deposition without weight loss in ob/ob mice. Int J Obes (Lond) 2020; 44:937-947. [PMID: 31911662 DOI: 10.1038/s41366-019-0513-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 11/07/2019] [Accepted: 12/11/2019] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Ectopic lipid deposition is closely associated with type 2 diabetes (T2D). Accumulating evidence shows that GLP-1 receptor agonists (GLP-1 RAs) improve obesity and liver steatosis. However, it remains unknown whether and how they ameliorate lipid deposition in skeletal muscle. This study aimed to investigate the effect of exenatide (a GLP-1 RA) on intramyocellular lipid deposition in the skeletal muscle of T2D models and its dependence on weight loss. METHODS Ob/ob mice and diet-induced obese (DIO) mice were treated with exenatide (24 nmol/kg), leptin (1 mg/kg), or saline control intraperitoneally once daily for 4 weeks. Phenotypic evaluations were performed during and after the intervention. PA-induced myoblast C2C12 cells were used as an in vitro model. The expression of key enzymes involved in lipid metabolism was assessed in the skeletal muscle of ob/ob mice and DIO mice. RESULTS In ob/ob mice, 4-week exenatide treatment did not improve the body weight and fat mass, but modestly ameliorated intramyocellular lipid deposition and lipid profiles. In DIO mice, it remarkably alleviated the body weight, lipid profiles, and intramyocellular lipid deposition. In the skeletal muscle of these two models, exenatide treatment activated the AMP-activated protein kinase (AMPK) signaling pathway, stimulated lipid oxidation enzymes, and upregulated the insulin signaling pathway. In vitro, exendin-4 activated the AMPK signaling pathway and stimulated lipid metabolism to improve lipid accumulation in palmitate-induced myoblast C2C12 cells. CONCLUSIONS Exenatide ameliorated intramyocellular lipid deposition without body weight reduction in ob/ob mice, but alleviated body weight and intramyocellular lipid deposition in DIO mice. The underlying mechanism included the activation of AMPK signaling pathway and improvement in insulin sensitivity, independent of weight loss in ob/ob mice.
Collapse
Affiliation(s)
- Fen Xu
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Huanyi Cao
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Zonglan Chen
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Huimin Gu
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha, China
| | - Wanrong Guo
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Beisi Lin
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Jianping Weng
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China. .,Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China.
| |
Collapse
|
7
|
Francisco V, Pino J, Campos-Cabaleiro V, Ruiz-Fernández C, Mera A, Gonzalez-Gay MA, Gómez R, Gualillo O. Obesity, Fat Mass and Immune System: Role for Leptin. Front Physiol 2018; 9:640. [PMID: 29910742 PMCID: PMC5992476 DOI: 10.3389/fphys.2018.00640] [Citation(s) in RCA: 243] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/11/2018] [Indexed: 12/13/2022] Open
Abstract
Obesity is an epidemic disease characterized by chronic low-grade inflammation associated with a dysfunctional fat mass. Adipose tissue is now considered an extremely active endocrine organ that secretes cytokine-like hormones, called adipokines, either pro- or anti-inflammatory factors bridging metabolism to the immune system. Leptin is historically one of most relevant adipokines, with important physiological roles in the central control of energy metabolism and in the regulation of metabolism-immune system interplay, being a cornerstone of the emerging field of immunometabolism. Indeed, leptin receptor is expressed throughout the immune system and leptin has been shown to regulate both innate and adaptive immune responses. This review discusses the latest data regarding the role of leptin as a mediator of immune system and metabolism, with particular emphasis on its effects on obesity-associated metabolic disorders and autoimmune and/or inflammatory rheumatic diseases.
Collapse
Affiliation(s)
- Vera Francisco
- The NEIRID Group (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Jesús Pino
- The NEIRID Group (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Victor Campos-Cabaleiro
- The NEIRID Group (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Clara Ruiz-Fernández
- The NEIRID Group (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Antonio Mera
- Servizo Galego de Saude, Division of Rheumatology, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Miguel A Gonzalez-Gay
- Epidemiology, Genetics and Atherosclerosis Research Group on Systemic Inflammatory Diseases, Hospital Universitario Marqués de Valdecilla, Universidad de Cantabria and IDIVAL, Santander, Spain
| | - Rodolfo Gómez
- Musculoskeletal Pathology Group, Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Oreste Gualillo
- The NEIRID Group (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Servizo Galego de Saude and Instituto de Investigación Sanitaria de Santiago, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| |
Collapse
|
8
|
Perez-Suarez I, Ponce-González JG, de La Calle-Herrero J, Losa-Reyna J, Martin-Rincon M, Morales-Alamo D, Santana A, Holmberg HC, Calbet JAL. Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle. J Appl Physiol (1985) 2017; 123:1276-1287. [DOI: 10.1152/japplphysiol.00454.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/22/2017] [Accepted: 07/19/2017] [Indexed: 11/22/2022] Open
Abstract
In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt−1·day−1) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt−1·day−1). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr1141OBR, phospho-Tyr985OBR, JAK2, and phospho-Tyr1007/1008JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr705STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r = −0.75), phospho-Tyr985OBR ( r = 0.88), and phospho-Tyr705STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles. NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling.
Collapse
Affiliation(s)
- Ismael Perez-Suarez
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | | | - Jaime de La Calle-Herrero
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Jose Losa-Reyna
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Marcos Martin-Rincon
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - David Morales-Alamo
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - Alfredo Santana
- Clinical Genetics Unit, Complejo Hospitalario Universitario Insular-Materno Infantil de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Jose A. L. Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, Las Palmas de Gran Canaria, Spain; and
| |
Collapse
|
9
|
Gibas-Dorna M, Piątek J, Kupsz J, Bernatek M, Krauss H, Sowińska A, Kołodziejski P, Owoc A, Bojar I. Relationship between adipokines and lipid profile in postmenopausal women with different apolipoprotein E genotypes. Women Health 2016; 57:891-904. [PMID: 27617395 DOI: 10.1080/03630242.2016.1235073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The aim of the authors of this study was to clarify the relationships among apolipoprotein E (ApoE) genotype, blood pressure, lipid profile, serum leptin, and adiponectin in healthy postmenopausal women. The study was conducted between March 2011 and December 2012 on 266 participants aged 50-65 years from the Institute of Rural Health in Lublin, Poland. Results showed that women had four combinations of genotypes: ɛ2/ɛ3, ɛ3/ɛ3, ɛ3/ɛ4, and ɛ4/ɛ4. Carriers of different genotypes did not differ in terms of age, body mass index (BMI), blood pressure, total cholesterol, high-density lipoprotein (HDL) cholesterol, and adiponectin levels. Mean low-density lipoprotein (LDL) cholesterol levels were higher in ε4 carriers compared to non-carriers. Fasting serum leptin concentrations were higher in homozygotes ɛ4/ɛ4. Leptin correlated positively with BMI in all study groups and with LDL in ɛ2/ɛ3, ɛ3/ɛ3, and ɛ3/ɛ4. Adiponectin correlated negatively with triglycerides in ɛ2/ɛ3, ɛ3/ɛ3, and ɛ3/ɛ4 and positively with HDL in ɛ2/ɛ3 carriers. Adipokines were not associated with blood pressure. Multiple regression analyses demonstrated associations among leptin, ApoE ɛ4/ɛ4, BMI, and LDL, and among adiponectin, BMI, and triglycerides. In healthy postmenopausal women ɛ4/ɛ4 genotype was associated with lower leptin levels. Homozygosity ɛ4/ɛ4 was associated with a more atherogenic lipid profile and possibly dysregulation of leptin and adiponectin signaling in lipid metabolism.
Collapse
Affiliation(s)
- Magdalena Gibas-Dorna
- a Department of Physiology , Poznan University of Medical Sciences , Poznan , Poland
| | - Jacek Piątek
- a Department of Physiology , Poznan University of Medical Sciences , Poznan , Poland
| | - Justyna Kupsz
- a Department of Physiology , Poznan University of Medical Sciences , Poznan , Poland
| | - Malgorzata Bernatek
- b Department of Hygiene , Poznan University of Medical Sciences , Poznan , Poland
| | - Hanna Krauss
- a Department of Physiology , Poznan University of Medical Sciences , Poznan , Poland
| | - Anna Sowińska
- c Department of Informatics and Statistics , Poznan University of Medical Sciences , Poznan , Poland
| | - Paweł Kołodziejski
- d Department of Animal Physiology and Biochemistry , University of Life Sciences in Poznan , Poznan , Poland
| | - Alfred Owoc
- e Center for Public Health and Health Promotion , Institute of Rural Health in Lublin , Lublin , Poland
| | - Iwona Bojar
- f Department of Women's Health , Institute of Rural Health in Lublin , Lublin , Poland
| |
Collapse
|
10
|
Tchang BG, Shukla AP, Aronne LJ. Metreleptin and generalized lipodystrophy and evolving therapeutic perspectives. Expert Opin Biol Ther 2016; 15:1061-75. [PMID: 26063386 DOI: 10.1517/14712598.2015.1052789] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Metreleptin was recently approved by the Food and Drug Administration for the treatment of generalized lipodystrophy, a condition characterized by leptin deficiency. Its efficacy as hormone replacement therapy suggests broader applications in diseases also characterized by leptin abnormalities, such as familial partial lipodystrophy (FPLD), non-alcoholic fatty liver disease (NAFLD), and common obesity. Metreleptin, in conjunction with other pharmacologic interventions, has the potential to address one of the most widespread epidemics of our time, obesity. AREAS COVERED This review covers the physiology of leptin, the pharmacologic properties of recombinant methionyl human leptin (R-metHu-Leptin, metreleptin), evidence for metreleptin's efficacy in the treatment of generalized lipodystrophy from both completed and ongoing clinical trials, safety concerns, and future directions in metreleptin research. EXPERT OPINION Metreleptin's approval for generalized lipodystrophy is the first step in defining and expanding its role to other metabolic diseases. Clinical trials are underway to delineate its efficacy in FPLD, human immunodeficiency virus/highly active anti-retroviral therapy-associated acquired lipodystrophy (HAL), and NAFLD. Additionally, there is growing data that support a therapeutic role in obesity. One of the barriers to development, however, is metreleptin's safety and immunogenicity. Further advances in biologic compatibility are required before metreleptin can be approved for additional indications.
Collapse
Affiliation(s)
- Beverly G Tchang
- Weill Cornell Medical College, Comprehensive Weight Control Center, Division of Endocrinology, Diabetes & Metabolism , 1165 York Avenue, New York, NY, 10065 , USA
| | | | | |
Collapse
|
11
|
Ibarra-Reynoso LDR, Pisarchyk L, Pérez-Luque EL, Garay-Sevilla ME, Malacara JM. Dietary restriction in obese children and its relation with eating behavior, fibroblast growth factor 21 and leptin: a prospective clinical intervention study. Nutr Metab (Lond) 2015; 12:31. [PMID: 26379757 PMCID: PMC4570615 DOI: 10.1186/s12986-015-0027-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/31/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Obesity is significant problem involving eating behavior and peripheral metabolic conditions. The effect of carbohydrate and fat restriction on appetite regulation, fibroblast growth factor 21 (FGF21) and leptin in children has not been defined. Our objective was to compare the effect of both diets. METHODS One hundred and twenty children with body mass index (BMI) higher than the equivalent of 30 kg/m(2) for an adult, as corrected for gender and age were randomly assigned to (n = 60) a low-carbohydrate (L-CHO) diet or (n = 60) a low-fat (L-F) diet for 2 months. Fifty-three (88.3 %) subjects on the low-carbohydrate-diet and 45 (75 %) on the low-fat diet completed the study. Anthropometric measures, leptin and FGF21 levels were measured before and after the intervention. Comparison of the data for both of the diet groups was carried out using the t-test for independent variables. Intragroup comparisons before and after of each of the dietary treatments were performed using ANOVA for repeated measures. Factors associated with FGF21, leptin levels and satiety, were analyzed by multiple regression. RESULTS After both of the diets, weight, leptin, food responsiveness, and enjoyment of food significantly decreased and high density lipoprotein cholesterol (HDL) increased, but FGF21 decreased. Before and after both of the interventions FGF21 was associated with triglycerides. Before the diet, satiety was associated with lower screen time (p < 0.04) and insulin levels (p < 0.05). CONCLUSIONS Both dietary restrictions improved the metabolic and hormonal parameters of obese children. FGF21 is an indicator of a beneficial metabolic response in younger children. After 2 months an adaptation of the eating behavior to food restriction was observed.
Collapse
Affiliation(s)
| | - Liudmila Pisarchyk
- Department of Medical Sciences, University of Guanajuato, Campus León. 20 de Enero 929. Col Obregón, León Gto, México 37320
| | - Elva Leticia Pérez-Luque
- Department of Medical Sciences, University of Guanajuato, Campus León. 20 de Enero 929. Col Obregón, León Gto, México 37320
| | - Ma Eugenia Garay-Sevilla
- Department of Medical Sciences, University of Guanajuato, Campus León. 20 de Enero 929. Col Obregón, León Gto, México 37320
| | - Juan Manuel Malacara
- Department of Medical Sciences, University of Guanajuato, Campus León. 20 de Enero 929. Col Obregón, León Gto, México 37320
| |
Collapse
|
12
|
Moon HS, Huh JY, Dincer F, Schneider BE, Hasselgren PO, Mantzoros CS. Identification and saturable nature of signaling pathways induced by metreleptin in humans: comparative evaluation of in vivo, ex vivo, and in vitro administration. Diabetes 2015; 64:828-39. [PMID: 25249580 PMCID: PMC4338590 DOI: 10.2337/db14-0625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Signaling pathways activated by leptin in metabolically important organs have largely been studied only in animal and/or cell culture studies. In this study, we examined whether leptin has similar effects in human peripheral tissues in vivo, ex vivo, and in vitro and whether the response would be different in lean and obese humans. For in vivo leptin signaling, metreleptin was administered and muscle, adipose tissue, and peripheral blood mononuclear cells were taken for analysis of signal activation. Experiments were also done ex vivo and with primary cultured cells in vitro. The signal activation was compared between male versus female and obese versus lean humans. Acute in vivo, ex vivo, and/or in vitro metreleptin administration similarly activated STAT3, AMPK, ERK1/2, Akt, mTOR, NF-κB, and/or IKKα/β without any differences between male versus female and obese versus lean subjects. All signaling pathways were saturable at ∼30-50 ng/mL, consistent with the clinical evidence showing no additional effect(s) in obese subjects who already have high levels of leptin. Our data provide novel information on downstream effectors of metreleptin action in humans that may have therapeutic implications.
Collapse
Affiliation(s)
- Hyun-Seuk Moon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Joo Young Huh
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Fadime Dincer
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Benjamin E Schneider
- Division of Minimally Invasive Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Per-Olof Hasselgren
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA
| |
Collapse
|
13
|
Abstract
The molecular mechanisms of body weight and body composition regulation have long been a research focus in the hopes of identifying tractable pathways for therapeutic interventions for obesity and diabetes, as well as related disorders such as nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) and polycystic ovary syndrome. The metabolic consequences of obesity and type 2 diabetes (T2D) were already a focus of the world's attention in 1994 when the discovery of leptin generated enormous enthusiasm for the potential to treat common (non-monogenic) obesity and its associated metabolic disorders with an adipokine hormone that regulated body weight as well as lipid and carbohydrate metabolism. Recombinant human leptin and many leptin analogs were developed and studied in animals and a few in human clinical trials. Overall, the opportunity for leptin as a therapeutic in unselected patients with obesity and T2D has not been substantiated in clinical trials. The potential for combination therapy suggested by clinical studies with leptin and pramlintide supports a path toward obesity treatment through the leptin pathway. The profound metabolic benefits seen with leptin in numerous forms of leptin deficiency, including lipodystrophy, provide hope for the opportunity to identify selected subsets of patients who could benefit from leptin treatment. This review provides a comprehensive overview of the clinical data on a subset of the potential utilities of leptin, specifically as a therapeutic for general or common obesity and its metabolic consequences including T2D and NAFLD/NASH.
Collapse
Affiliation(s)
- Alex M DePaoli
- NGM BiopharmaceuticalsDevelopment, 630 Gateway Boulevard, South San Francisco, California 94080, USA
| |
Collapse
|
14
|
Sarvas JL, Niccoli S, Walser E, Khaper N, Lees SJ. Interleukin-6 deficiency causes tissue-specific changes in signaling pathways in response to high-fat diet and physical activity. Physiol Rep 2014; 2:2/7/e12064. [PMID: 24997069 PMCID: PMC4187557 DOI: 10.14814/phy2.12064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This study was designed to investigate the role of interleukin‐6 (IL‐6) on high‐fat diet (HFD)‐induced glucose intolerance, and the response to voluntary physical activity in the prevention of insulin resistance. Six‐week‐old wild‐type (WT) and IL‐6 knockout (KO) mice with (RUN) or without (SED) access to running wheels were fed a HFD (60% from kcal) for 4 weeks. A glucose tolerance test revealed that blood glucose levels were 25–30% higher in KO RUN compared to all other groups. In WT RUN, weight gain was positively correlated with total caloric intake; however, this correlation was absent in KO RUN. In soleus muscle, there was a 2‐fold increase in SOCS3 expression in KO RUN compared to all other groups. In gastrocnemius and plantaris muscles, Akt phosphorylation was 31% higher in WT RUN compared to WT SED, but this effect of running was absent in KO mice. Additionally, there was a 2.4‐fold increase in leptin expression in KO RUN compared to KO SED in the gastrocnemius and plantaris muscles. In the liver, there was a 2‐ to 3.8‐fold increase in SOCS3 expression in KO SED compared to all other groups, and AMPKα phosphorylation was 27% higher in WT mice (both RUN and SED) compared to KO mice (both RUN and SED). This study provides new insights into the role of the IL‐6 in metabolism and energy storage, and highlights tissue‐specific changes in early signaling pathways in response to HFD for 4 weeks. The collective findings suggest that endogenous IL‐6 is important for the prevention of insulin resistance leading to type 2 diabetes. This study was designed to investigate the role of interleukin‐6 (IL‐6) on high‐fat diet (HFD)‐induced glucose intolerance, and the response to voluntary physical activity in the prevention of insulin resistance. This study provides new insight into the role of the IL‐6 in metabolism and energy storage, and highlights tissue‐specific changes in early signaling pathways in response to HFD for 4 weeks. The collective findings suggest that endogenous IL‐6 is important for the prevention of insulin resistance leading to type 2 diabetes.
Collapse
Affiliation(s)
- Jessica L Sarvas
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Sarah Niccoli
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada
| | - Eric Walser
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Neelam Khaper
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Simon J Lees
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| |
Collapse
|
15
|
Guadalupe-Grau A, Larsen S, Guerra B, Calbet JAL, Dela F, Helge JW. Influence of age on leptin induced skeletal muscle signalling. Acta Physiol (Oxf) 2014; 211:214-28. [PMID: 24605926 DOI: 10.1111/apha.12273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/03/2013] [Accepted: 03/04/2014] [Indexed: 12/27/2022]
Abstract
AIM Age associated fat mass accumulation could be because of dysregulation of leptin signalling in skeletal muscle. Thus, we investigated total protein expression and phosphorylation levels of the long isoform of the leptin receptor (OB-Rb), and leptin signalling through janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), insulin receptor substrate 1 (IRS-1), AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC), combined with the leptin signalling inhibitors suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in human skeletal muscle of different age. METHODS Vastus lateralis muscle biopsies were obtained from 39 men matched for BMI < 30 kg m(-2) and separated into three groups: 13 young (Y, 24 ± 4 years); 14 middle aged (MA, 44 ± 5 years) and 12 aged (A, 58 ± 8 years) subjects. RESULTS Whole body fat percentage and plasma leptin were higher (P < 0.05), whereas lean mass, plasma free testosterone and total testosterone were lower (P < 0.05) in A compared to Y. Skeletal muscle OB-Rb (170 KDa) protein expression and pTyr(1141) -OB-R170 were comparable between groups, whereas pTyr(985) -OB-R170 was lower in A compared to Y (P < 0.05). pSTAT3 levels tended (P = 0.09) to be lower (50%) in A compared to Y. In A, muscle PTP1B was greater and IRS-1 lower than Y and MA respectively (P < 0.05). PTyr(612) -IRS-1 tended to be lower in A than in Y (P = 0.09). Suppressor of cytokine signalling 3 (SOCS3) protein expression, pJAK2, pSer(1101) -IRS-1, pAMPKα and pACCβ were similar between groups. CONCLUSION Age is associated with dysregulation of the leptin signalling and increased PTP1B protein expression in skeletal muscle.
Collapse
Affiliation(s)
- A. Guadalupe-Grau
- Department of Physical Education; University of Las Palmas de Gran Canaria; Las Palmas de Gran Canaria Spain
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - S. Larsen
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - B. Guerra
- Department of Clinical Sciences; Molecular and Translational Endocrinology Group; Associate Unit of University of Las Palmas de Gran Canaria and Biomedical Institute “Alberto Sols” - CSIC; Las Palmas de Gran Canaria Spain
- ICIC; Cancer Research Institute of the Canary Islands; Las Palmas de Gran Canaria Spain
- Instituto Universitario de Investigaciones Biomédicas y Sanitarias; Las Palmas de Gran Canaria Spain
| | - J. A. L. Calbet
- Department of Physical Education; University of Las Palmas de Gran Canaria; Las Palmas de Gran Canaria Spain
- Instituto Universitario de Investigaciones Biomédicas y Sanitarias; Las Palmas de Gran Canaria Spain
| | - F. Dela
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - J. W. Helge
- Xlab; Department of Biomedical Sciences; Faculty of Health Sciences; Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| |
Collapse
|
16
|
Stears A, Hames C. Diagnosis and management of lipodystrophy: a practical update. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.14.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
17
|
Wium C, Gulseth HL, Eriksen EF, Birkeland KI. Characteristics of glucose metabolism in Nordic and South Asian subjects with type 2 diabetes. PLoS One 2013; 8:e83983. [PMID: 24391858 PMCID: PMC3877129 DOI: 10.1371/journal.pone.0083983] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/11/2013] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Insulin resistance and type 2 diabetes are more prevalent in people of South Asian ethnicity than in people of Western European origin. To investigate the source of these differences, we compared insulin sensitivity, insulin secretion, glucose and lipid metabolism in South Asian and Nordic subjects with type 2 diabetes. METHODS Forty-three Nordic and 19 South Asian subjects with type 2 diabetes were examined with intra-venous glucose tolerance test, euglycemic clamp including measurement of endogenous glucose production, indirect calorimetry measuring glucose and lipid oxidation, and dual x-ray absorptiometry measuring body composition. RESULTS Despite younger mean ± SD age (49.7 ± 9.4 vs 58.3 ± 8.3 years, p = 0.001), subjects of South Asian ethnicity had the same diabetes duration (9.3 ± 5.5 vs 9.6 ± 7.0 years, p = 0.86), significantly higher median [inter-quartile range] HbA1c (8.5 [1.6] vs 7.3 [1.6] %, p = 0.024) and lower BMI (28.7 ± 4.0 vs 33.2 ± 4.7 kg/m(2), p<0.001). The South Asian group exhibited significantly higher basal endogenous glucose production (19.1 [9.1] vs 14.4 [6.8] µmol/kgFFM · min, p = 0.003). There were no significant differences between the groups in total glucose disposal (39.1 ± 20.4 vs 39.2 ± 17.6 µmol/kgFFM · min, p = 0.99) or first phase insulin secretion (AUC0-8 min: 220 [302] vs 124 [275] pM, p = 0.35). In South Asian subjects there was a tendency towards positive correlations between endogenous glucose production and resting and clamp energy expenditure. CONCLUSIONS Subjects of South Asian ethnicity with type 2 diabetes, despite being younger and leaner, had higher basal endogenous glucose production, indicating higher hepatic insulin resistance, and a trend towards higher use of carbohydrates as fasting energy substrate compared to Nordic subjects. These findings may contribute to the understanding of the observed differences in prevalence of type 2 diabetes between the ethnic groups.
Collapse
Affiliation(s)
- Cecilie Wium
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway
- Hormone Laboratory, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
- * E-mail:
| | - Hanne Løvdal Gulseth
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway
- Hormone Laboratory, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Erik Fink Eriksen
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kåre Inge Birkeland
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| |
Collapse
|
18
|
Guerra B, Ponce-González JG, Morales-Alamo D, Guadalupe-Grau A, Kiilerich K, Fuentes T, Ringholm S, Biensø RS, Santana A, Lundby C, Pilegaard H, Calbet JAL. Leptin signaling in skeletal muscle after bed rest in healthy humans. Eur J Appl Physiol 2013; 114:345-57. [PMID: 24292882 DOI: 10.1007/s00421-013-2779-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 11/18/2013] [Indexed: 12/22/2022]
Abstract
PURPOSE This study aimed at determining the effects of bed rest on the skeletal muscle leptin signaling system. METHODS Deltoid and vastus lateralis muscle biopsies and blood samples were obtained from 12 healthy young men (mean ± SD, BMI 22.8 ± 2.7 kg/m(2)) before and after 7 days of bed rest. Leptin receptor isoforms (OB-Rs), suppressor of cytokine signaling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) protein expression and signal transducer and activator of transcription 3 (STAT3) phosphorylation were analyzed by Western blot. RESULTS After bed rest basal insulin concentration was increased by 53% (P < 0.05), the homeostasis model assessment (HOMA) by 40% (P < 0.05), and serum leptin concentration by 35% (P < 0.05) with no changes in body fat mass. Although the soluble isoform of the leptin receptor (s-OBR) remained unchanged, the molar excess of leptin over sOB-R was increased by 1.4-fold after bed rest (P < 0.05). OB-Rs and SOCS3 protein expression, and STAT3 phosphorylation level remained unaffected in deltoid and vastus lateralis by bed rest, as PTP1B in the deltoid. PTP1B was increased by 90% with bed rest in the vastus lateralis (P < 0.05). There was a linear relationship between the increase in vastus lateralis PTP1B and the increase in both basal insulin concentrations (r = 0.66, P < 0.05) and HOMA (r = 0.68, P < 0.05) with bed rest. CONCLUSIONS One week of bed rest is associated with increased leptin levels without augmenting STAT3 phosphorylation indicating some degree of leptin resistance in skeletal muscle, which can be explained, at least in part, by an elevation of PTP1B protein content in the vastus lateralis muscle.
Collapse
Affiliation(s)
- Borja Guerra
- Departamento de Educación Física, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017, Las Palmas de Gran Canaria, Canary Island, Spain,
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Schinzari F, Tesauro M, Rovella V, Di Daniele N, Mores N, Veneziani A, Cardillo C. Leptin stimulates both endothelin-1 and nitric oxide activity in lean subjects but not in patients with obesity-related metabolic syndrome. J Clin Endocrinol Metab 2013; 98:1235-41. [PMID: 23372172 DOI: 10.1210/jc.2012-3424] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Leptin has nitric oxide (NO)-dependent vasodilator actions, but hyperleptinemia is an independent risk factor for cardiovascular disease. OBJECTIVE The objective of the study was to investigate whether, in the human circulation, properties of leptin to release NO are opposed by stimulation of vasculotoxic substances, such as endothelin (ET)-1, and whether this mechanism might contribute to vascular damage in hyperleptinemic states like obesity. METHODS Forearm blood flow responses (plethysmography) to ETA receptor antagonism (BQ-123, 10 nmol/min) and NO synthase inhibition [N(G)-monomethyl L-arginine (L-NMMA), 4 μmol/min] were assessed before and after intraarterial administration of leptin (2 μg/min) in lean controls (n = 8) and patients with obesity-related metabolic syndrome (MetS; n = 8). RESULTS Baseline plasma leptin was higher in patients than in controls (P < .001). Before infusion of leptin, the vasodilator response to BQ-123 was greater in patients than in controls (P < .001), whereas infusion of L-NMMA induced higher vasoconstriction in controls than in patients (P = .04). In lean subjects, hyperleptinemia resulted in increased vasodilator response to ETA receptor antagonism (P < .001 vs before) and enhanced vasoconstrictor effect of L-NMMA during ETA receptor blockade (P = .015 vs before). In patients with the MetS, by contrast, vascular responses to both BQ-123 and L-NMMA were not modified by exogenous leptin (both P > .05 vs before). CONCLUSIONS These findings indicate that, under physiological conditions, leptin stimulates both ET-1 and NO activity in the human circulation. This effect is absent in hyperleptinemic patients with the MetS who are unresponsive to additional leptin. In these patients, therefore, hyperleptinemia may be a biomarker of vascular dysfunction, rather than a mediator of vascular damage.
Collapse
Affiliation(s)
- Francesca Schinzari
- Department of Internal Medicine, Catholic University Medical School, 00168 Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
20
|
Sarvas JL, Khaper N, Lees SJ. The IL-6 Paradox: Context Dependent Interplay of SOCS3 and AMPK. ACTA ACUST UNITED AC 2013; Suppl 13. [PMID: 24244888 DOI: 10.4172/2155-6156.s13-003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Insulin resistance is the principle step towards the progression of type 2 diabetes, and has been linked to increased circulating levels of cytokines, leading to chronic low-grade inflammation. Specifically, in chronic disease states increased IL-6 is thought to play a critical role in the regulation of insulin resistance in the peripheral tissues, and has been used as a marker of insulin resistance. There is also an endogenous up-regulation of IL-6 in response to exercise, which has been linked to improved insulin sensitivity. This leads to the question "how can elevated IL-6 lead to the development of insulin resistance, and yet also lead to increased insulin sensitivity?" Resolving the dual role of IL-6 in regulating insulin resistance/sensitivity is critical to the development of potential therapeutic interventions. This review summarizes the literature on the seemingly paradoxical role of elevated IL-6 on insulin signalling, including the activation of AMPK and the involvement of leptin and SOCS3.
Collapse
|
21
|
Wolsk E, Mygind H, Grøndahl TS, Pedersen BK, van Hall G. Human skeletal muscle releases leptin in vivo. Cytokine 2012; 60:667-73. [DOI: 10.1016/j.cyto.2012.08.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 01/27/2023]
|