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Turner RT, Branscum AJ, Iwaniec UT. Long-duration leptin transgene expression in dorsal vagal complex does not alter bone parameters in female Sprague Dawley rats. Bone Rep 2024; 21:101769. [PMID: 38706522 PMCID: PMC11067478 DOI: 10.1016/j.bonr.2024.101769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/07/2024] Open
Abstract
The hypothalamus and dorsal vagal complex (DVC) are both important for integration of signals that regulate energy balance. Increased leptin transgene expression in either the hypothalamus or DVC of female rats was shown to decrease white adipose tissue and circulating levels of leptin and adiponectin. However, in contrast to hypothalamus, leptin transgene expression in the DVC had no effect on food intake, circulating insulin, ghrelin and glucose, nor on thermogenic energy expenditure. These findings imply different roles for hypothalamus and DVC in leptin signaling. Leptin signaling is required for normal bone accrual and turnover. Leptin transgene expression in the hypothalamus normalized the skeletal phenotype of leptin-deficient ob/ob mice but had no long-duration (≥10 weeks) effects on the skeleton of leptin-replete rats. The goal of this investigation was to determine the long-duration effects of leptin transgene expression in the DVC on the skeleton of leptin-replete rats. To accomplish this goal, we analyzed bone from three-month-old female rats that were microinjected with recombinant adeno-associated virus encoding either rat leptin (rAAV-Leptin, n = 6) or green fluorescent protein (rAAV-GFP, control, n = 5) gene. Representative bones from the appendicular (femur) and axial (3rd lumbar vertebra) skeleton were evaluated following 10 weeks of treatment. Selectively increasing leptin transgene expression in the DVC had no effect on femur cortical or cancellous bone microarchitecture. Additionally, increasing leptin transgene expression had no effect on vertebral osteoblast-lined or osteoclast-lined bone perimeter or marrow adiposity. Taken together, the findings suggest that activation of leptin receptors in the DVC has minimal specific effects on the skeleton of leptin-replete female rats.
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Affiliation(s)
- Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
- Center for Healthy Aging Research, Oregon State University, Corvallis, OR 97331, USA
| | - Adam J. Branscum
- Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
- Center for Healthy Aging Research, Oregon State University, Corvallis, OR 97331, USA
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2
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Maia RDCA, Lima TC, Barbosa CM, Barbosa MA, de Queiroz KB, Alzamora AC. Intergenerational inheritance induced by a high-fat diet causes hyperphagia and reduced hypothalamic sensitivity to insulin and leptin in the second-generation of rats. Nutrition 2024; 120:112333. [PMID: 38271759 DOI: 10.1016/j.nut.2023.112333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/16/2023] [Accepted: 12/18/2023] [Indexed: 01/27/2024]
Abstract
OBJECTIVE The aim was to investigate the intergenerational inheritance induced by a high-fat diet on sensitivity to insulin and leptin in the hypothalamic control of satiety in second-generation offspring, which were fed a control diet. METHODS Progenitor rats were fed a high-fat or a control diet for 59 d until weaning. The first-generation and second-generation offspring were fed the control diet until 90 d of age. Body mass and adiposity index of the progenitors fed the high-fat diet and the second-generation offspring from progenitors fed the high-fat diet were evaluated as were the gene expression of DNA methyltransferase 3a, angiotensin-converting enzyme type 2, angiotensin II type 2 receptor, insulin and leptin signaling pathway (insulin receptor, leptin receptor, insulin receptor substrate 2, protein kinase B, signal transducer and transcriptional activator 3, pro-opiomelanocortin, and neuropeptide Agouti-related protein), superoxide dismutase activity, and the concentration of carbonyl protein and satiety-regulating neuropeptides, pro-opiomelanocortin and neuropeptide Agouti-related protein, in the hypothalamus. RESULTS The progenitor group fed a high-fat diet showed increased insulin resistance and reduced insulin-secreting beta-cell function and reduced food intake, without changes in caloric intake. The second-generation offspring from progenitors fed a high-fat diet, compared with second-generation offspring from progenitors fed a control diet group, had decreased insulin-secreting beta-cell function and increased food and caloric intake, insulin resistance, body mass, and adiposity index. Furthermore, second-generation offspring from progenitors fed a high-fat diet had increased DNA methyltransferase 3a, neuropeptide Agouti-related protein, angiotensin II type 1 receptor, and nicotinamide adenine dinucleotide phosphate oxidase p47phox gene expression, superoxide dismutase activity, and neuropeptide Agouti-related protein concentration in the hypothalamus. In addition, there were reduced in gene expression of the insulin receptor, leptin receptor, insulin receptor substrate 2, pro-opiomelanocortin, angiotensin II type 2 receptor, angiotensin-converting enzyme type 2, and angiotensin-(1-7) receptor and pro-opiomelanocortin concentration in the second-generation offspring from progenitors fed the high-fat diet. CONCLUSIONS Overall, progenitors fed a high-fat diet induced changes in the hypothalamic control of satiety of the second-generation offspring from progenitors fed the high-fat diet through intergenerational inheritance. These changes led to hyperphagia, alterations in the hypothalamic pathways of insulin, and leptin and adiposity index increase, favoring the occurrence of different cardiometabolic disorders in the second-generation offspring from progenitors fed the high-fat diet fed only with the control diet.
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Affiliation(s)
- Rosana da Conceição Araújo Maia
- Núcleo de Pesquisa em Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Taynara Carolina Lima
- Núcleo de Pesquisa em Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Claudiane Maria Barbosa
- Núcleo de Pesquisa em Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Maria Andréa Barbosa
- Núcleo de Pesquisa em Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Karina Barbosa de Queiroz
- Departamento de Alimentos, Escola de Nutrição, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Andréia Carvalho Alzamora
- Núcleo de Pesquisa em Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil; Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil.
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3
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Tucker JAL, Bornath DPD, McCarthy SF, Hazell TJ. Leptin and energy balance: exploring Leptin's role in the regulation of energy intake and energy expenditure. Nutr Neurosci 2024; 27:87-95. [PMID: 36583502 DOI: 10.1080/1028415x.2022.2161135] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Leptin is a tonic appetite-regulating hormone, which is integral for the long-term regulation of energy balance. The current evidence suggests that the typical orexigenic or anorexigenic response of many of these appetite-regulating hormones, most notably ghrelin and cholecystokinin (CCK), require leptin to function whereas glucagon-like peptide-1 (GLP-1) is required for leptin to function, and these responses are altered when leptin injection or gene therapy is administered in combination with these same hormones or respective agonists. The appetite-regulatory pathway is complex, thus peptide tyrosine tyrosine (PYY), brain-derived neurotrophic factor (BDNF), orexin-A (OXA), and amylin also maintain ties to leptin, however these are less well understood. While reviews to date have focused on the existing relationships between leptin and the various neuropeptide modulators of appetite within the central nervous system (CNS) or it's role in thermogenesis, no review paper has synthesised the information regarding the interactions between appetite-regulating hormones and how leptin as a chronic regulator of energy balance can influence the acute appetite-regulatory response. Current evidence suggests that potential relationships exist between leptin and the circulating peripheral appetite hormones ghrelin, GLP-1, CCK, OXA and amylin to exhibit either synergistic or opposing effects on appetite inhibition. Though more research is warranted, leptin appears to be integral in both energy intake and energy expenditure. More specifically, functional leptin receptors appear to play an essential role in these processes.
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Affiliation(s)
- Jessica A L Tucker
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Canada
| | - Derek P D Bornath
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Canada
| | - Seth F McCarthy
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Canada
| | - Tom J Hazell
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Canada
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4
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Clark KA, Shin AC, Sirivelu MP, MohanKumar RC, Maddineni SR, Ramachandran R, MohanKumar PS, MohanKumar SMJ. Evaluation of the Central Effects of Systemic Lentiviral-Mediated Leptin Delivery in Streptozotocin-Induced Diabetic Rats. Int J Mol Sci 2021; 22:ijms222413197. [PMID: 34947993 PMCID: PMC8703968 DOI: 10.3390/ijms222413197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 11/16/2022] Open
Abstract
Type 1 diabetes (T1D) is characterized by hyperphagia, hyperglycemia and activation of the hypothalamic-pituitary-adrenal (HPA) axis. We have reported previously that daily leptin injections help to alleviate these symptoms. Therefore, we hypothesized that leptin gene therapy could help to normalize the neuroendocrine dysfunction seen in T1D. Adult male Sprague Dawley rats were injected i.v. with a lentiviral vector containing the leptin gene or green fluorescent protein. Ten days later, they were injected with the vehicle or streptozotocin (STZ). HPA function was assessed by measuring norepinephrine (NE) levels in the paraventricular nucleus (PVN) and serum corticosterone (CS). Treatment with the leptin lentiviral vector (Lepvv) increased leptin and insulin levels in non-diabetic rats, but not in diabetic animals. There was a significant reduction in blood glucose levels in diabetic rats due to Lepvv treatment. Both NE levels in the PVN and serum CS were reduced in diabetic rats treated with Lepvv. Results from this study provide evidence that leptin gene therapy in STZ-induced diabetic rats was able to partially normalize some of the neuroendocrine abnormalities, but studies with higher doses of the Lepvv are needed to develop this into a viable option for treating T1D.
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MESH Headings
- Animals
- Corticosterone/blood
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/therapy
- Diabetes Mellitus, Type 1/chemically induced
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/therapy
- Disease Models, Animal
- Genetic Therapy
- Genetic Vectors/administration & dosage
- Injections, Intravenous
- Lentivirus/genetics
- Leptin/genetics
- Male
- Norepinephrine/metabolism
- Paraventricular Hypothalamic Nucleus/metabolism
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Kimberly A. Clark
- Neuroscience Graduate Program, Michigan State University, E. Lansing, MI 48824, USA; (K.A.C.); (P.S.M.)
| | - Andrew C. Shin
- Neurobiology of Nutrition Laboratory, Department of Nutritional Sciences, College of Human Sciences, Texas Tech University, Lubbock, TX 79409, USA;
| | - Madhu P. Sirivelu
- Pathobiology and Diagnostic Investigation, Michigan State University, E. Lansing, MI 48824, USA;
| | - Ramya C. MohanKumar
- Neuroendocrine Research Laboratory, University of Georgia, Athens, GA 30602, USA;
| | - Sreenivasa R. Maddineni
- Department of Poultry Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (S.R.M.); (R.R.)
| | - Ramesh Ramachandran
- Department of Poultry Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (S.R.M.); (R.R.)
| | - Puliyur S. MohanKumar
- Neuroscience Graduate Program, Michigan State University, E. Lansing, MI 48824, USA; (K.A.C.); (P.S.M.)
- Pathobiology and Diagnostic Investigation, Michigan State University, E. Lansing, MI 48824, USA;
- Neuroendocrine Research Laboratory, University of Georgia, Athens, GA 30602, USA;
- Department of Biomedical Sciences, University of Georgia, Athens, GA 30602, USA
| | - Sheba M. J. MohanKumar
- Neuroscience Graduate Program, Michigan State University, E. Lansing, MI 48824, USA; (K.A.C.); (P.S.M.)
- Neuroendocrine Research Laboratory, University of Georgia, Athens, GA 30602, USA;
- Department of Biomedical Sciences, University of Georgia, Athens, GA 30602, USA
- Correspondence: ; Tel.: +1-706-542-1945
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5
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Ashok T, Puttam H, Tarnate VCA, Jhaveri S, Avanthika C, Trejo Treviño AG, Sl S, Ahmed NT. Role of Vitamin B12 and Folate in Metabolic Syndrome. Cureus 2021; 13:e18521. [PMID: 34754676 PMCID: PMC8569690 DOI: 10.7759/cureus.18521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2021] [Indexed: 12/11/2022] Open
Abstract
Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS. In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12. According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.
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Affiliation(s)
- Tejaswini Ashok
- Internal Medicine, Jagadguru Sri Shivarathreeshwara Medical College, Mysore, IND
| | - Harivarsha Puttam
- Internal Medicine, Employees' State Insurance Corporation Medical College and Hospital, Hyderabad, IND
| | | | - Sharan Jhaveri
- Internal Medicine, Smt. Nathiba Hargovandas Lakhmichand Municipal Medical College, Ahmedabad, IND
| | - Chaithanya Avanthika
- Medicine and Surgery, Karnataka Institute of Medical Sciences, Hubli, IND.,Pediatrics, Karnataka Institute of Medical Sciences, Hubli, IND
| | | | - Sandeep Sl
- Internal Medicine, SRM Medical College Hospital & Research Centre, Kattankulathur, IND
| | - Nazia T Ahmed
- Medicine, Shahabuddin Medical College and Hospital, Dhaka, BGD
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6
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Turner RT, Wong CP, Fosse KM, Branscum AJ, Iwaniec UT. Caloric Restriction and Hypothalamic Leptin Gene Therapy Have Differential Effects on Energy Partitioning in Adult Female Rats. Int J Mol Sci 2021; 22:ijms22136789. [PMID: 34202651 PMCID: PMC8269114 DOI: 10.3390/ijms22136789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/04/2021] [Accepted: 06/18/2021] [Indexed: 12/14/2022] Open
Abstract
Dieting is a common but often ineffective long-term strategy for preventing weight gain. Similar to humans, adult rats exhibit progressive weight gain. The adipokine leptin regulates appetite and energy expenditure but hyperleptinemia is associated with leptin resistance. Here, we compared the effects of increasing leptin levels in the hypothalamus using gene therapy with conventional caloric restriction on weight gain, food consumption, serum leptin and adiponectin levels, white adipose tissue, marrow adipose tissue, and bone in nine-month-old female Sprague-Dawley rats. Rats (n = 16) were implanted with a cannula in the 3rd ventricle of the hypothalamus and injected with a recombinant adeno-associated virus, encoding the rat gene for leptin (rAAV-Lep), and maintained on standard rat chow for 18 weeks. A second group (n = 15) was calorically-restricted to match the weight of the rAAV-Lep group. Both approaches prevented weight gain, and no differences in bone were detected. However, calorically-restricted rats consumed 15% less food and had lower brown adipose tissue Ucp-1 mRNA expression than rAAV-Lep rats. Additionally, calorically-restricted rats had higher abdominal white adipose tissue mass, higher serum leptin and adiponectin levels, and higher marrow adiposity. Caloric restriction and hypothalamic leptin gene therapy, while equally effective in preventing weight gain, differ in their effects on energy intake, energy expenditure, adipokine levels, and body composition.
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Affiliation(s)
- Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA; (R.T.T.); (C.P.W.); (K.M.F.)
| | - Carmen P. Wong
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA; (R.T.T.); (C.P.W.); (K.M.F.)
| | - Kristina M. Fosse
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA; (R.T.T.); (C.P.W.); (K.M.F.)
| | - Adam J. Branscum
- Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA;
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA; (R.T.T.); (C.P.W.); (K.M.F.)
- Correspondence:
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7
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Barrios V, Frago LM, Canelles S, Guerra-Cantera S, Arilla-Ferreiro E, Chowen JA, Argente J. Leptin Modulates the Response of Brown Adipose Tissue to Negative Energy Balance: Implication of the GH/IGF-I Axis. Int J Mol Sci 2021; 22:2827. [PMID: 33799501 PMCID: PMC8001882 DOI: 10.3390/ijms22062827] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/26/2021] [Accepted: 03/09/2021] [Indexed: 01/09/2023] Open
Abstract
The growth hormone (GH)/insulin-like growth factor I (IGF-I) axis is involved in metabolic control. Malnutrition reduces IGF-I and modifies the thermogenic capacity of brown adipose tissue (BAT). Leptin has effects on the GH/IGF-I axis and the function of BAT, but its interaction with IGF-I and the mechanisms involved in the regulation of thermogenesis remains unknown. We studied the GH/IGF-I axis and activation of IGF-I-related signaling and metabolism related to BAT thermogenesis in chronic central leptin infused (L), pair-fed (PF), and control rats. Hypothalamic somatostatin mRNA levels were increased in PF and decreased in L, while pituitary GH mRNA was reduced in PF. Serum GH and IGF-I concentrations were decreased only in PF. In BAT, the association between suppressor of cytokine signaling 3 and the IGF-I receptor was reduced, and phosphorylation of the IGF-I receptor increased in the L group. Phosphorylation of Akt and cyclic AMP response element binding protein and glucose transporter 4 mRNA levels were increased in L and mRNA levels of uncoupling protein-1 (UCP-1) and enzymes involved in lipid anabolism reduced in PF. These results suggest that modifications in UCP-1 in BAT and changes in the GH/IGF-I axis induced by negative energy balance are dependent upon leptin levels.
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Affiliation(s)
- Vicente Barrios
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
| | - Laura M. Frago
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
- Department of Pediatrics, Faculty of Medicine, Universidad Autónoma de Madrid, E-28029 Madrid, Spain
| | - Sandra Canelles
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
| | - Santiago Guerra-Cantera
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
- Department of Pediatrics, Faculty of Medicine, Universidad Autónoma de Madrid, E-28029 Madrid, Spain
| | - Eduardo Arilla-Ferreiro
- Department of Biological Systems, Faculty of Medicine, Universidad de Alcalá, E-28871 Alcalá de Henares, Spain;
| | - Julie A. Chowen
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
- CEI UAM + CSIC, IMDEA Food Institute, E-28049 Madrid, Spain
| | - Jesús Argente
- Department of Endocrinology, Instituto de Investigación La Princesa, Hospital Infantil Universitario Niño Jesús, E-28009 Madrid, Spain; (L.M.F.); (S.C.); (S.G.-C.); (J.A.C.)
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain
- Department of Pediatrics, Faculty of Medicine, Universidad Autónoma de Madrid, E-28029 Madrid, Spain
- CEI UAM + CSIC, IMDEA Food Institute, E-28049 Madrid, Spain
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8
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Ribeiro MJ, Sacramento JF, Gallego-Martin T, Olea E, Melo BF, Guarino MP, Yubero S, Obeso A, Conde SV. High fat diet blunts the effects of leptin on ventilation and on carotid body activity. J Physiol 2018; 596:3187-3199. [PMID: 29271068 DOI: 10.1113/jp275362] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 12/13/2017] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Leptin plays a role in the control of breathing, acting mainly on central nervous system; however, leptin receptors have been recently shown to be expressed in the carotid body (CB), and this finding suggests a physiological role for leptin in the regulation of CB function. Leptin increases minute ventilation in both basal and hypoxic conditions in rats. It increases the frequency of carotid sinus nerve discharge in basal conditions, as well as the release of adenosine from the CB. However, in a metabolic syndrome animal model, the effects of leptin in ventilatory control, carotid sinus nerve activity and adenosine release by the CB are blunted. Although leptin may be involved in triggering CB overactivation in initial stages of obesity and dysmetabolism, resistance to leptin signalling and blunting of responses develops in metabolic syndrome animal models. ABSTRACT Leptin plays a role in the control of breathing, acting mainly on central nervous system structures. Leptin receptors are expressed in the carotid body (CB) and this finding has been associated with a putative physiological role of leptin in the regulation of CB function. Since, the CBs are implicated in energy metabolism, here we tested the effects of different concentrations of leptin administration on ventilatory parameters and on carotid sinus nerve (CSN) activity in control and high-fat (HF) diet fed rats, in order to clarify the role of leptin in ventilation control in metabolic disease states. We also investigated the expression of leptin receptors and the neurotransmitters involved in leptin signalling in the CBs. We found that in non-disease conditions, leptin increases minute ventilation in both basal and hypoxic conditions. However, in the HF model, the effect of leptin in ventilatory control is blunted. We also observed that HF rats display an increased frequency of CSN discharge in basal conditions that is not altered by leptin, in contrast to what is observed in control animals. Leptin did not modify intracellular Ca2+ in CB chemoreceptor cells, but it produced an increase in the release of adenosine from the whole CB. We conclude that CBs represent an important target for leptin signalling, not only to coordinate peripheral ventilatory chemoreflexive drive, but probably also to modulate metabolic variables. We also concluded that leptin signalling is mediated by adenosine release and that HF diets blunt leptin responses in the CB, compromising ventilatory adaptation.
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Affiliation(s)
- Maria J Ribeiro
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Teresa Gallego-Martin
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Elena Olea
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Bernardete F Melo
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Maria P Guarino
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.,School of Health Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
| | - Sara Yubero
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Silvia V Conde
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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9
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Chandra Mouli K, Pragathi D, Naga Jyothi U, Shanmuga Kumar V, Himalaya Naik M, Balananda P, Suman B, Seshadri Reddy V, Vijaya T. Leptin inhibitors from fungal endophytes (LIFEs): Will be novel therapeutic drugs for obesity and its associated immune mediated diseases. Med Hypotheses 2016; 92:48-53. [PMID: 27241254 DOI: 10.1016/j.mehy.2016.04.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 04/11/2016] [Accepted: 04/18/2016] [Indexed: 12/20/2022]
Abstract
Treatment of obesity and its associated immune mediated diseases is challenging due to impaired function of leptin system. Thus leptin is providing an interesting target for therapeutic intervention. Leptin, an adipose tissue-derived adipokine, displays a variety of immune functions, and regulate both innate and adaptive immune responses. The increased secretion of leptin (hyperleptinemia) and production of proinflammatory cytokines has been implicated in the pathogenesis of obesity-related immune diseases such as diabetes mellitus, hypertension, atherosclerosis, cancer, systemic lupus erythematosus, rheumatoid arthritis, crohn's disease and multiple sclerosis. These disorders are managed through antibiotics and by cytokines replacement. However, the effectiveness of cytokines coupled to the complexity of the cytokine network leads to severe side-effects, which can still occur after careful preclinical evaluation. In addition, synthetic immunotherapeutics carries a degree of risk, is time-consuming and expensive. Hence, the complexity of existing therapy and adverse effects emphasizes the need of an alternative approach for the management of immune dysfunction associated with obesity and its related diseases. For the aforementioned diseases that are related to leptin overabundance, new drugs blocking leptin signaling need to be generated. The research on the discovery of clinically important novel compounds from natural source is expanding due to their safety and no side effect. The fungal endophytes are the microbes that colonize internal tissue of plants without causing negative effects to the host. They produce plethora of substances of potential use to modern medicinal and pharmaceutical industry. The increasing body of evidence associated with application of bioactive metabolites derived from fungal endophytes in diverse disease states merits its use as therapeutic drugs. In particular, the saponins have been extensively proved to modulate the immune system, which has raised a significant interest in their potential as immunomodulators. Thus, our hypothesis is that the saponins derived from fungal endophytes can be explored as clinical applicable leptin inhibitors for treating immune mediated diseases.
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Affiliation(s)
- K Chandra Mouli
- Department of Biotechnology, Vikrama Simhapuri University, Nellore, Andhra Pradesh, India.
| | - D Pragathi
- Department of Biotechnology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - U Naga Jyothi
- Department of Botany, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - V Shanmuga Kumar
- Department of Biotechnology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - M Himalaya Naik
- Department of Biotechnology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - P Balananda
- Department of Physiology, GIMSR, GITAM University, Visakhapatnam, Andhra Pradesh, India
| | - B Suman
- Department of Biochemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - V Seshadri Reddy
- Department of Biochemistry, BPS Govt Medical College for Women, Sonepat, Haryana, India
| | - T Vijaya
- Department of Botany, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
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10
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Turner RT, Dube M, Branscum AJ, Wong CP, Olson DA, Zhong X, Kweh MF, Larkin IV, Wronski TJ, Rosen CJ, Kalra SP, Iwaniec UT. Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss. J Endocrinol 2015; 227:129-41. [PMID: 26487675 PMCID: PMC4917201 DOI: 10.1530/joe-15-0280] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/14/2015] [Indexed: 02/04/2023]
Abstract
Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin, n=7) or a control vector encoding green fluorescent protein (rAAV-GFP, n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (-4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (-80%), serum leptin (-77%), and serum IGF1 (-34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover.
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Affiliation(s)
- Russell T Turner
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Michael Dube
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Adam J Branscum
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Carmen P Wong
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Dawn A Olson
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Xiaoying Zhong
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Mercedes F Kweh
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Iske V Larkin
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Thomas J Wronski
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Clifford J Rosen
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Satya P Kalra
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
| | - Urszula T Iwaniec
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USACenter for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USADepartment of NeuroscienceMcKnight Brain Institute, University of Florida, Gainesville, Florida, USABiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USADepartment of Physiological SciencesUniversity of Florida, Gainesville, Florida, USADepartment of Large Animal Clinical SciencesUniversity of Florida, Gainesville, Florida, USAMaine Medical Center Research InstituteScarborough, Maine, USA
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11
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A Hyperlipidic Diet Combined with Short-Term Ovariectomy Increases Adiposity and Hyperleptinemia and Decreases Cytokine Content in Mesenteric Adipose Tissue. Mediators Inflamm 2015; 2015:923248. [PMID: 26170534 PMCID: PMC4485502 DOI: 10.1155/2015/923248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 04/10/2015] [Accepted: 04/17/2015] [Indexed: 12/22/2022] Open
Abstract
Four-week-old female Wistar rats were divided into two groups and fed a control diet (C) or a hyperlipidic diet (H) for 4 weeks. Rats from each group underwent ovariectomy (OVX) or sham surgery (SHAM). They received C or H for the next four weeks. The body weight gain (BW), food efficiency (FE), and carcass lipid content were higher in the OVX H than in the SHAM H. The OVX H exhibited a higher serum leptin level than other groups. IL-6, TNF-α, and IL-10 content of mesenteric (MES) adipose tissue was lower in the OVX H than in the OVX C. IL-6, TNF-α, and IL-10 content of retroperitoneal (RET) adipose tissue was lower in the SHAM H than in the SHAM C. The SHAM H showed decreased TG relative to the SHAM C. Similar results were obtained in relation to IL-6Rα, TNFR1, TLR-4, and MyD88 contents in the MES and RET white adipose tissue among the groups. A hyperlipidic diet for 8 weeks combined with short-term ovariectomy decreases the cytokine content of MES adipose tissues but increases BW, enhancing FE and elevating serum leptin levels. These suggest that the absence of estrogens promotes metabolic changes that may contribute to installation of a proinflammatory process induced by a hyperlipidic diet.
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12
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Resveratrol increases nephrin and podocin expression and alleviates renal damage in rats fed a high-fat diet. Nutrients 2014; 6:2619-31. [PMID: 25025298 PMCID: PMC4113760 DOI: 10.3390/nu6072619] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/09/2014] [Accepted: 06/27/2014] [Indexed: 11/17/2022] Open
Abstract
Resveratrol is well known for its anti-inflammation and anti-oxidant properties, and has been shown to be effective in alleviating the development of obesity. The purpose of this investigation was to analyze the effect of resveratrol on renal damage in obese rats induced by a high-fat diet (HFD) and its possible mechanisms. Male Sprague-Dawley rats were divided into three groups: control, HFD, and HFD plus resveratrol (treated with 100 mg/kg/day resveratrol). Body weight, serum and urine metabolic parameters, and kidney histology were measured. Meanwhile, the activities of nuclear factor-κB (NF-κB) and superoxide dismutase (SOD), the content of malondialdehyde (MDA), and the protein levels of tumor necrosis factor (TNF-α), monocyte chemotactic protein-1 (MCP-1), nephrin and podocin in kidney were detected. Our work showed that resveratrol alleviated dyslipidemia and renal damage induced by HFD, decreased MDA level and increased SOD activity. Furthermore, the elevated NF-κB activity, increased TNF-α and MCP-1 levels, and reduced expressions of nephrin and podocin induced by HFD were significantly reversed by resveratrol. These results suggest resveratrol could ameliorate renal injury in rats fed a HFD, and the mechanisms are associated with suppressing oxidative stress and NF-κB signaling pathway that in turn up-regulate nephrin and podocin protein expression.
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13
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Zhang Q, Liu B, Cheng Y, Meng Q, Xia T, Jiang L, Chen S, Liu Y, Guo F. Leptin signaling is required for leucine deprivation-enhanced energy expenditure. J Biol Chem 2013; 289:1779-87. [PMID: 24302741 DOI: 10.1074/jbc.m113.528943] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Leptin signaling in the hypothalamus is crucial in energy homeostasis. We have previously shown that dietary deprivation of the essential amino acid leucine in mice stimulates fat loss by increasing energy expenditure. The involvement of leptin signaling in this regulation, however, has not been reported. Here, we show that leucine deprivation promotes leptin signaling in mice maintained on an otherwise normal diet and restores leptin responses in mice maintained on a high fat diet, a regimen known to induce leptin resistance. In addition, we found that leucine deprivation stimulated energy expenditure, and fat loss was largely blocked in db/db mice homozygous for a mutation in leptin receptor and a knock-in mouse line Y3F with abrogation of leptin receptor Tyr(1138)-mediated signal transducer and activator transcript 3 signaling. Overall, our studies describe a novel link between hypothalamic leptin signaling and stimulation of energy expenditure under leucine deprivation.
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Affiliation(s)
- Qian Zhang
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
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14
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Leptin as a neuroprotective agent in glaucoma. Med Hypotheses 2013; 81:797-802. [PMID: 24035688 DOI: 10.1016/j.mehy.2013.08.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/05/2013] [Accepted: 08/22/2013] [Indexed: 11/22/2022]
Abstract
Glaucoma is a disease characterized by progressive optic nerve degeneration and is the leading cause of irreversible blindness worldwide. More than 60 million people globally are affected by glaucoma, of which 8 million people suffer from bilateral blindness, making glaucoma the second leading cause of bilateral blindness worldwide. Current management of glaucoma is aimed at reducing intraocular pressure via a number of different strategies. Current treatments do not attempt to correct the underlying pathology of glaucoma, which is the cell degeneration and ultimate death of retinal ganglion cells, thereby limiting their clinical efficacy. A neuroprotective approach to glaucoma management would address the underlying pathology and would, in theory, be beneficial to all patients regardless of risk and causative factors. Here it is proposed that leptin could be used as a potential neuroprotective agent in the management of glaucoma. Leptin has shown neuroprotective promise in a number of neurodegenerative diseases, and there has been increasing evidence that glaucomatous neurodegeneration is analogous to other neurodegenerative diseases in the central nervous system. Leptin could target retinal ganglion cell death by a number of mechanisms, namely apoptosis, oxidative stress and excitotoxicity reduction. This article presents evidence linking current understanding about leptin's neuroprotective effect and the molecular mechanisms underlying glaucoma.
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15
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Effects of a diet enriched with polyunsaturated, saturated, or trans fatty acids on cytokine content in the liver, white adipose tissue, and skeletal muscle of adult mice. Mediators Inflamm 2013; 2013:594958. [PMID: 24027356 PMCID: PMC3762081 DOI: 10.1155/2013/594958] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/18/2013] [Accepted: 07/11/2013] [Indexed: 02/06/2023] Open
Abstract
This study analyzed the effect of diet enriched with 30% lipids on cytokines content in different tissues. Swiss male mice were distributed into four groups treated for 8 weeks with control (C, normolipidic diet); soybean oil (S); lard (L); and hydrogenated vegetable fat (H). We observed an increase in carcass fat in groups S and L, and the total amount of fatty deposits was only higher in group L compared with C group. The serum levels of free fatty acids were lower in the L group, and insulin, adiponectin, lipid profile, and glucose levels were similar among the groups. IL-10 was lower in group L in mesenteric and retroperitoneal adipose tissues. H reduced IL-10 only in retroperitoneal adipose tissue. There was an increase in IL-6 in the gastrocnemius muscle of the L group, and a positive correlation between TNF-α and IL-10 was observed in the livers of groups C, L, and H and in the muscles of all groups studied. The results suggested relationships between the quantity and quality of lipids ingested with adiposity, the concentration of free fatty acids, and cytokine production in white adipose tissue, gastrocnemius muscle, and liver.
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16
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Amitani M, Asakawa A, Amitani H, Inui A. The role of leptin in the control of insulin-glucose axis. Front Neurosci 2013; 7:51. [PMID: 23579596 PMCID: PMC3619125 DOI: 10.3389/fnins.2013.00051] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 03/18/2013] [Indexed: 12/21/2022] Open
Abstract
Obesity and diabetes mellitus are great public health concerns throughout the world because of their increasing incidence and prevalence. Leptin, the adipocyte hormone, is well known for its role in the regulation of food intake and energy expenditure. In addition to the regulation of appetite and satiety that recently has attracted much attentions, insight has also been gained into the critical role of leptin in the control of the insulin-glucose axis, peripheral glucose and insulin responsiveness. Since the discovery of leptin, leptin has been taken for its therapeutic potential to obesity and diabetes. Recently, the therapeutic effects of central leptin gene therapy have been reported in insulin-deficient diabetes in obesity animal models such as ob/ob mise, diet-induced obese mice, and insulin-deficient type 1 diabetes mice, and also in patients with inactivating mutations in the leptin gene. Herein, we review the role of leptin in regulating feeding behavior and glucose metabolism and also the therapeutic potential of leptin in obesity and diabetes mellitus.
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Affiliation(s)
- Marie Amitani
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
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17
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Diabetes Mellitus: New Challenges and Innovative Therapies. NEW STRATEGIES TO ADVANCE PRE/DIABETES CARE: INTEGRATIVE APPROACH BY PPPM 2013; 3. [PMCID: PMC7120768 DOI: 10.1007/978-94-007-5971-8_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Diabetes is a common chronic disease affecting an estimated 285 million adults worldwide. The rising incidence of diabetes, metabolic syndrome, and subsequent vascular diseases is a major public health problem in industrialized countries. This chapter summarizes current pharmacological approaches to treat diabetes mellitus and focuses on novel therapies for diabetes mellitus that are under development. There is great potential for developing a new generation of therapeutics that offer better control of diabetes, its co-morbidities and its complications. Preclinical results are discussed for new approaches including AMPK activation, the FGF21 target, cell therapy approaches, adiponectin mimetics and novel insulin formulations. Gene-based therapies are among the most promising emerging alternatives to conventional treatments. Therapies based on gene silencing using vector systems to deliver interference RNA to cells (i.e. against VEGF in diabetic retinopathy) are also a promising therapeutic option for the treatment of several diabetic complications. In conclusion, treatment of diabetes faces now a new era that is characterized by a variety of innovative therapeutic approaches that will improve quality of life in the near future.
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Abstract
Diabetes is a major worldwide problem. Despite some progress in the development of new antidiabetic agents, the ability to maintain tight glycemic control in order to prevent renal, retinal, and neuropathic complications of diabetes without adverse complications still remains a challenge. Recent evidence suggests, however, that in addition to playing a key role in the regulation of energy homeostasis, the adiposity hormone leptin also plays an important role in the control of glucose metabolism via its actions in the brain. This review examines the role of leptin action in the central nervous system and the mechanisms whereby leptin mediates its effects to regulate glucose metabolism. These findings suggest that defects or dysfunction in leptin signaling may contribute to the etiology of diabetes and raise the possibility that either leptin or downstream targets of leptin may have therapeutic potential for the treatment of diabetes.
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Affiliation(s)
- Thomas H. Meek
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Gregory J. Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA, USA
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Nakano M, Asakawa A, Inui A. Long-term correction of type 1 and 2 diabetes by central leptin gene therapy independent of effects on appetite and energy expenditure. Indian J Endocrinol Metab 2012; 16:S556-S561. [PMID: 23565490 PMCID: PMC3602984 DOI: 10.4103/2230-8210.105572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adipocyte-derived leptin is a hormone associated with the regulation of energy homeostasis, including glucose metabolism. Hyperleptinemia, induced by the consumption of energy-enriched diets, inhibits leptin transport across the blood-brain barrier, and thereby produces leptin insufficiency in the hypothalamus. As a result of sustained leptin insufficiency, the hypothalamic restraint on pancreatic insulin secretion is lost. Additionally, both glucose metabolism and energy expenditure are also diminished, and both type 1 and type 2 diabetes are induced. A replication-deficient recombinant adeno-associated virus vector engineered to encode the leptin gene (rAVV-LEP) has been used in models of diabetes as a novel therapeutic approach. After rAVV-LEP injection in ob/ob mice, hypothalamic leptin expression was increased, body weight was suppressed, and hyperinsulinemia was ameliorated. Additionally injection of rAVV-LEP into the hypothalamus suppressed the expression of orexigenic neuropeptide Y (NPY) and enhanced anorexigenic pro-opiomelanocortin (POMC) in the arcuate nucleus (ARC) in rats. It is proposed that central leptin gene therapy should be tested clinically to reduce the worldwide epidemic of obesity, diabetes, and shortened life span. In this article, the information has been assembled from published review articles on this topic.
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Affiliation(s)
- Masako Nakano
- Department of Social and Behavioral Medicine, Kagoshima University Graduate Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Asakawa
- Department of Social and Behavioral Medicine, Kagoshima University Graduate Medical and Dental Sciences, Kagoshima, Japan
| | - Akio Inui
- Department of Social and Behavioral Medicine, Kagoshima University Graduate Medical and Dental Sciences, Kagoshima, Japan
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20
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Affiliation(s)
- Satya P. Kalra
- Department of Neuroscience and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, 32610, USA
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21
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Villaverde N, Galvis A, Marcano A, Priestap HA, Bennett BC, Barbieri MA. Saw palmetto ethanol extract inhibits adipocyte differentiation. J Nat Med 2012. [PMID: 23179316 DOI: 10.1007/s11418-012-0723-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The fruits of saw palmetto have been used for the treatment of a variety of urinary and reproductive system problems. In this study we investigated whether the fruit extracts affect in vitro adipogenesis. Saw palmetto ethanol extract inhibited the lipid droplet accumulation by induction media in a dose-dependent manner, and it also attenuated the protein expressions of C-EBPα and PPARγ. Phosphorylation of Erk1/2 and Akt1 were also decreased by saw palmetto ethanol extract. This report suggests that saw palmetto extracts selectively affect the adipocyte differentiation through the modulation of several key factors that play a critical role during adipogenesis.
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Affiliation(s)
- Nicole Villaverde
- Department of Biological Sciences, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
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Hambly C, Adams A, Fustin JM, Rance KA, Bünger L, Speakman JR. Mice with Low Metabolic Rates Are Not Susceptible to Weight Gain When Fed a High-Fat Diet. ACTA ACUST UNITED AC 2012; 13:556-66. [PMID: 15833941 DOI: 10.1038/oby.2005.59] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Mice divergently selected for high or low food intake (FI) at constant body mass differ in their resting metabolic rates (RMRs). Low-intake individuals (ML) have significantly lower RMR (by 30%) compared with those from the high-intake line (MH). We hypothesized that MLs might, therefore, be more likely to increase their body and fat mass when exposed to a high-fat diet (HFD). RESEARCH METHODS AND PROCEDURES We exposed both lines to a diet with 44.9% calories from fat for 3 weeks while measuring FI, fecal production, and body mass and then returned the mice to standard chow. RESULTS When exposed to the HFD, both lines significantly decreased their FI (MH, 40% to 45%; ML, 31% to 35%). This decrease occurred simultaneously with a significant increase in apparent energy absorption efficiency (AEAE). When returned to chow, FI and AEAE returned to the levels observed prior to HFD exposure. Because of the adjustments in FI, the absorbed energy was maintained in the MLs and, thus, body mass remained constant. The MH individuals overcompensated for the elevated energy content and AEAE on the HFD and, therefore, absorbed lower energy than when feeding on chow. These mice also did not significantly change their body mass when on the HFD and must have made adjustments in their energy expenditures. Both lines and both sexes increased in fat content on the HFD, but these effects were not different between lines or sexes. DISCUSSION We found no support for the hypothesis that mice with low RMRs were more susceptible to weight gain when fed the HFD.
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Affiliation(s)
- Catherine Hambly
- School of Biological Sciences, Aberdeen Center for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, UK.
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23
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Jung CH, Ahn J, Jeon TI, Kim TW, Ha TY. Syzygium aromaticum ethanol extract reduces high-fat diet-induced obesity in mice through downregulation of adipogenic and lipogenic gene expression. Exp Ther Med 2012. [PMID: 23181109 PMCID: PMC3503535 DOI: 10.3892/etm.2012.609] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Numerous medicinal plants and their derivatives have been reported to prevent obesity and related diseases. Although Syzygium aromaticum has traditionally been used as an anodyne, carminative and anthelmintic in Asian countries, its potential in the prevention and treatment of obesity has not yet been explored. Therefore, the present study investigated the anti-obesity effect of S. aromaticum ethanol extract (SAE) both in vitro and in vivo. To evaluate the anti-obesity potential of SAE in vitro, the effect of SAE treatment on adipocyte differentiation in 3T3-L1 cells was investigated. To evaluate its potential in vivo, mice were assigned to three groups: a group fed the American Institute of Nutrition AIN-76A diet (normal group), an experimental group fed a high-fat diet (HFD group) and an experimental group fed an HFD supplemented with 0.5% (w/w) SAE (HFD + SAE group). After 9 weeks of feeding, the body weight; white adipose tissue (WAT) mass; serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, glucose, insulin and leptin; hepatic lipid accumulation; and levels of lipid metabolism-related genes in the liver and WAT were measured. In vitro investigation of the effect of SAE treatment on 3T3-L1 cells revealed that it had efficiently inhibited the conversion of cells into adipocytes in a dose-dependent manner. In vivo investigation revealed that SAE supplementation had significantly decreased HFD-induced increases in the body weight, liver weight, WAT mass, and serum TG, TC, lipid, glucose, insulin and leptin levels. Consistent with its effects on liver weight and WAT mass, SAE supplementation was found to have suppressed the expression of lipid metabolism-related proteins, including SREBP-1, FAS, CD36 and PPARγ in the liver and WAT, in addition to downregulating mRNA levels of transcription factors including Srebp and Pparg. SAE inhibits fat accumulation in HFD-fed mice via the suppression of transcription factors integral to adipogenesis and lipogenesis, suggesting its potential in preventing obesity.
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Affiliation(s)
- Chang Hwa Jung
- Division of Metabolism and Functionality Research, Korea Food Research Institute, Seongnam 463-746
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24
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Patrikakos P, Toutouzas KG, Gazouli M, Perrea D, Menenakos E, Papadopoulos S, Zografos G. Long-term plasma ghrelin and leptin modulation after sleeve gastrectomy in Wistar rats in comparison with gastric tissue ghrelin expression. Obes Surg 2012; 21:1432-7. [PMID: 21611877 DOI: 10.1007/s11695-011-0426-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Sleeve gastrectomy (SG) is a gaining ground operation amongst the ones applied for treatment of morbid obesity. Though SG is a food limiting operation, the removal of the gastric fundus where ghrelin is mainly produced may indicate a hormonal impact of the procedure. The purpose of this experiment is to study how SG affects the levels of ghrelin and leptin. METHODS Twenty-four male, adult, diet induced obese Wistar rats were divided randomly into groups, one submitted to SG and the other to a sham operation. Fasting blood samples were taken before the operation and 14 weeks after the operation (leptin and acylated and des-acyl ghrelin levels were measured). Tissue samples from the gastric fundus were taken during the operation and at the end of the experiment, and ghrelin expression was measured with RT-PCR. RESULTS Statistically significant weight loss was achieved comparing the weight progress of the SG group and the sham operation group. Serum leptin levels were significantly reduced in the SG group (p < 0.05) but not in the sham operation group. Serum acylated ghrelin was not significantly affected in both groups, but a significant decrease was documented in serum des-acyl ghrelin in the SG group (p < 0.05). RT-PCR analysis of the gastric fundus documented a significant decrease (p < 0.0001) in the expression of ghrelin in the SG group. CONCLUSIONS SG may lead in significant long-term weight loss. SG affects the serum levels of leptin and des-acyl ghrelin but not the levels of acylated ghrelin in this animal model.
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Affiliation(s)
- Panagiotis Patrikakos
- 1st Department of Propaedeutic Surgery, Hippocration Hospital, Athens Medical School, Athens, Greece
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25
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Engineer DR, Garcia JM. Leptin in anorexia and cachexia syndrome. INTERNATIONAL JOURNAL OF PEPTIDES 2012; 2012:287457. [PMID: 22518191 PMCID: PMC3303568 DOI: 10.1155/2012/287457] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/25/2011] [Accepted: 10/28/2011] [Indexed: 12/31/2022]
Abstract
Leptin is a product of the obese (OB) gene secreted by adipocytes in proportion to fat mass. It decreases food intake and increases energy expenditure by affecting the balance between orexigenic and anorexigenic hypothalamic pathways. Low leptin levels are responsible for the compensatory increase in appetite and body weight and decreased energy expenditure (EE) following caloric deprivation. The anorexia-cachexia syndrome is a complication of many chronic conditions including cancer, chronic obstructive pulmonary disease, congestive heart failure, chronic kidney disease, and aging, where the decrease in body weight and food intake is not followed by a compensatory increase in appetite or decreased EE. Crosstalk between leptin and inflammatory signaling known to be activated in these conditions may be responsible for this paradox. This manuscript will review the evidence and potential mechanisms mediating changes in the leptin pathway in the setting of anorexia and cachexia associated with chronic diseases.
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Affiliation(s)
- Diana R. Engineer
- Division of Diabetes, Endocrinology and Metabolism, Michael E DeBakey Veterans Affairs Medical Center, Houston, TX 77030, USA
- Baylor College of Medicine, 2002 Holcombe Boulevored, Building 109, Room 210, Houston, TX 77030, USA
- Division of Diabetes, Department of Medicine, Endocrinology and Metabolism, St Luke's Episcopal Hospital, Houston, TX 77030, USA
| | - Jose M. Garcia
- Division of Diabetes, Endocrinology and Metabolism, Michael E DeBakey Veterans Affairs Medical Center, Houston, TX 77030, USA
- Baylor College of Medicine, 2002 Holcombe Boulevored, Building 109, Room 210, Houston, TX 77030, USA
- Huffington Center of Aging, Baylor College of Medicine, Houston, TX 77030, USA
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26
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Obesity and the ageing brain: could leptin play a role in neurodegeneration? Curr Gerontol Geriatr Res 2011; 2011:708154. [PMID: 22013440 PMCID: PMC3195276 DOI: 10.1155/2011/708154] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 08/15/2011] [Indexed: 01/19/2023] Open
Abstract
Obesity and ageing are both characteristics of the human population that are on the increase across the globe. It has long been established that ageing is the major risk factor for neurodegenerative conditions such as Alzheimer's disease, and it is becoming increasingly evident that obesity is another such factor. Leptin resistance or insensitivity has been uncovered as a cause of obesity, and in addition the leptin signalling system is less potent in the elderly. Taken together, these findings reveal that this molecule may be a link between neurodegeneration and obesity or ageing. It is now known that leptin has beneficial effects on both the survival and neurophysiology of the neurons that are lost in Alzheimer's disease suggesting that it may be an important research target in the quest for strategies to prevent, halt, or cure this condition.
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Hwang KH, Ahn JY, Kim S, Park JH, Ha TY. Abietic Acid Has an Anti-Obesity Effect in Mice Fed a High-Fat Diet. J Med Food 2011; 14:1052-6. [DOI: 10.1089/jmf.2010.1471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kwang-Hyun Hwang
- Functional Food Technology Research Group, Korea Food Research Institute, Seongnam, Korea
| | - Ji-Yun Ahn
- Functional Food Technology Research Group, Korea Food Research Institute, Seongnam, Korea
| | - Suna Kim
- Functional Food Technology Research Group, Korea Food Research Institute, Seongnam, Korea
| | - Jae-Ho Park
- Functional Food Technology Research Group, Korea Food Research Institute, Seongnam, Korea
| | - Tae-Youl Ha
- Functional Food Technology Research Group, Korea Food Research Institute, Seongnam, Korea
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Iwaniec UT, Boghossian S, Trevisiol CH, Wronski TJ, Turner RT, Kalra SP. Hypothalamic leptin gene therapy prevents weight gain without long-term detrimental effects on bone in growing and skeletally mature female rats. J Bone Miner Res 2011; 26:1506-16. [PMID: 21328617 PMCID: PMC3129999 DOI: 10.1002/jbmr.365] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Hypothalamic leptin gene therapy normalizes the mosaic skeletal phenotype of leptin-deficient ob/ob mice. However, it is not clear whether increased hypothalamic leptin alters bone metabolism in animals already producing the hormone. The objective of this study was to evaluate the long duration effects of recombinant adeno-associated virus-rat leptin (rAAV-Lep) hypothalamic gene therapy on weight gain and bone metabolism in growing and skeletally mature leptin-replete female Sprague-Dawley rats. Rats were either unoperated or implanted with cannulas in the third ventricle of the hypothalamus and injected with either rAAV-Lep or rAAV-GFP (control vector encoding green fluorescent protein) and maintained on standard rat chow fed ad libitum for either 5 or 10 weeks (starting at 3 months of age) or 18 weeks (starting at 9 months of age). Tibias, femurs, or lumbar vertebrae were analyzed by micro-computed tomography and/or histomorphometry. In comparison with age-matched rAAV-GFP rats, rAAV-Lep rats maintained a lower body weight for the duration of studies. At 5 weeks after vector administration, rAAV-Lep rats had lower cancellous bone volume and bone marrow adiposity but higher osteoblast perimeter compared with nonoperated controls. However, these values did not differ between the two groups at 10 weeks after vector administration. Differences in cancellous bone volume and architecture were not detected between the rAAV-Lep and rAAV-GFP groups at either time point. Also, rAAV-Lep had no negative effects on bone in the 9-month-old skeletally mature rats at 18 weeks after vector administration. We hypothesize that the transient reductions in bone mass and bone marrow adiposity at 5 weeks after vector administration were due to hypothalamic surgery. We conclude that increased hypothalamic leptin, sufficient to prevent weight gain, has minimal specific effects (rAAV-Lep versus rAAV-GFP) on bone metabolism in normal female rats.
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Affiliation(s)
- Urszula T Iwaniec
- Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331, USA.
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29
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Ikarashi N, Toda T, Okaniwa T, Ito K, Ochiai W, Sugiyama K. Anti-Obesity and Anti-Diabetic Effects of Acacia Polyphenol in Obese Diabetic KKAy Mice Fed High-Fat Diet. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 2011:952031. [PMID: 21799697 PMCID: PMC3137845 DOI: 10.1093/ecam/nep241] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 12/12/2009] [Indexed: 12/16/2022]
Abstract
Acacia polyphenol (AP) extracted from the bark of the black wattle tree (Acacia meansii) is rich in unique catechin-like flavan-3-ols, such as robinetinidol and fisetinidol. The present study investigated the anti-obesity/anti-diabetic effects of AP using obese diabetic KKAy mice. KKAy mice received either normal diet, high-fat diet or high-fat diet with additional AP for 7 weeks. After the end of administration, body weight, plasma glucose and insulin were measured. Furthermore, mRNA and protein expression of obesity/diabetic suppression-related genes were measured in skeletal muscle, liver and white adipose tissue. As a result, compared to the high-fat diet group, increases in body weight, plasma glucose and insulin were significantly suppressed for AP groups. Furthermore, compared to the high-fat diet group, mRNA expression of energy expenditure-related genes (PPARα, PPARδ, CPT1, ACO and UCP3) was significantly higher for AP groups in skeletal muscle. Protein expressions of CPT1, ACO and UCP3 for AP groups were also significantly higher when compared to the high-fat diet group. Moreover, AP lowered the expression of fat acid synthesis-related genes (SREBP-1c, ACC and FAS) in the liver. AP also increased mRNA expression of adiponectin and decreased expression of TNF-α in white adipose tissue. In conclusion, the anti-obesity actions of AP are considered attributable to increased expression of energy expenditure-related genes in skeletal muscle, and decreased fatty acid synthesis and fat intake in the liver. These results suggest that AP is expected to be a useful plant extract for alleviating metabolic syndrome.
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Affiliation(s)
- Nobutomo Ikarashi
- Department of Clinical Pharmacokinetics, Hoshi University, Tokyo, Japan
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30
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Kalra SP. Pivotal role of leptin-hypothalamus signaling in the etiology of diabetes uncovered by gene therapy: a new therapeutic intervention? Gene Ther 2011; 18:319-25. [PMID: 21209624 DOI: 10.1038/gt.2010.164] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The incidence of diabetes mellitus has soared to epidemic proportion worldwide. The debilitating chronic hyperglycemia is caused by either lack of insulin as in diabetes type 1 or its ineffectiveness as in diabetes type 2. Frequent replacement of insulin with or without insulin analogs for optimum glycemic control are the conventional cumbersome therapies. Recent application of leptin gene transfer technology has uncovered the participation of adipocytes-derived leptin-dependent hypothalamic neural signaling in glucose homeostasis and demonstrated that a breakdown in this communication due to leptin insufficiency in the hypothalamus underlies the etiology of chronic hyperglycemia. Reinstatement of central leptin sufficiency by hyperleptinemia produced either by intravenous leptin infusion or a single systemic injection of recombinant adenovirus vector encoding leptin gene suppressed hyperglycemia and evoked euglycemia only transiently in rodent models of diabetes type 1. In contrast, stable restoration of leptin sufficiency, solely in the hypothalamus, with biologically active leptin transduced by an intracerebroventicular injection of recombinant adeno-associated virus vector encoding leptin gene (rAAV-lep) abolished hyperglycemia and imposed euglycemia through the extended duration of experiment by stimulating glucose disposal in the periphery in models of diabetes type 1. Further, similar hypothalamic leptin transgene expression abrogated chronic hyperglycemia and hyperinsulinemia, the predisposing risk factors of the age and environmentally acquired diabetes type 2, and instituted euglycemia by independently activating relays that stimulate glucose metabolism and repress hyperinsulinemia and improve insulin sensitivity in the periphery. Consequently, this durable antidiabetic efficacy of one time rAAV-lep neurotherapy offers a potential novel substitute for insulin therapy following preclinical trials in subhuman primates and humans.
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Affiliation(s)
- S P Kalra
- Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610-0244, USA.
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Davidson EP, Coppey LJ, Dake B, Yorek MA. Effect of Treatment of Sprague Dawley Rats with AVE7688, Enalapril, or Candoxatril on Diet-Induced Obesity. J Obes 2011; 2011:686952. [PMID: 20847891 PMCID: PMC2933895 DOI: 10.1155/2011/686952] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/29/2010] [Indexed: 12/30/2022] Open
Abstract
The objective of this study was to determine the effect of AVE7688, a drug that inhibits both angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) activity, on neural and vascular defects caused by diet induced obesity (DIO). Rats at 12 weeks of age were fed a standard or high fat diet with or without AVE7688 for 24 weeks. DIO rats had impaired glucose tolerance and developed sensory neuropathy. Vascular relaxation to acetylcholine and calcitonin gene-related peptide was decreased in epineurial arterioles of DIO rats. Rats fed a high fat diet containing AVE7688 did not become obese and vascular and sensory nerve dysfunction and impaired glucose tolerance were improved. DIO is associated with increased expression of NEP in epineurial arterioles. NEP degrades vasoactive peptides which may explain the decrease in neurovascular function in DIO.
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Affiliation(s)
- Eric P. Davidson
- Veteran Affairs Medical Center, Iowa City, IA 52246, USA
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Lawrence J. Coppey
- Veteran Affairs Medical Center, Iowa City, IA 52246, USA
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Brian Dake
- Veteran Affairs Medical Center, Iowa City, IA 52246, USA
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Mark A. Yorek
- Veteran Affairs Medical Center, Iowa City, IA 52246, USA
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
- *Mark A. Yorek:
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32
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Han G, Jing Y, Zhang Y, Yue Z, Hu X, Wang L, Liang J, Liu J. Osteogenic differentiation of bone marrow mesenchymal stem cells by adenovirus-mediated expression of leptin. ACTA ACUST UNITED AC 2010; 163:107-12. [PMID: 20433876 DOI: 10.1016/j.regpep.2010.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 04/18/2010] [Accepted: 04/20/2010] [Indexed: 02/07/2023]
Abstract
Previous studies demonstrate that leptin has an osteogenic differentiation effect on bone marrow mesenchymal stem cells (MSCs). However, the effect of adenovirus-mediated leptin on MSCs differentiation has not been reported. To explore the mechanism, we constructed a recombinant adenoviral vector Ad-leptin and transfected propagated MSCs in vitro. The effects of Ad-leptin on MSCs growth and osteogenic differentiation were examined. The results showed that Ad-leptin inhibited the transfected MSCs growth significantly, and up-regulated osteocalcin expression and alkaline phosphatase activity. The expression of Cbfalpha1 and Cbfbeta which were the key factors in osteogenic differentiation was also up-regulated. All the findings suggest that genetic engineering of MSCs to express leptin gene may have potential application in the treatment of several genetic diseases and bone reconstruction.
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Affiliation(s)
- Guosheng Han
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
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Sena CM, Bento CF, Pereira P, Seiça R. Diabetes mellitus: new challenges and innovative therapies. EPMA J 2010; 1:138-63. [PMID: 23199048 PMCID: PMC3405309 DOI: 10.1007/s13167-010-0010-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 02/04/2010] [Indexed: 12/25/2022]
Abstract
Diabetes mellitus is a widespread disease prevalence and incidence of which increases worldwide. The introduction of insulin therapy represented a major breakthrough in type 1 diabetes; however, frequent hyper- and hypoglycemia seriously affects the quality of life of these patients. New therapeutic approaches, such as whole pancreas transplant or pancreatic islet transplant, stem cell, gene therapy and islets encapsulation are discussed in this review. Regarding type 2 diabetes, therapy has been based on drugs that stimulate insulin secretion (sulphonylureas and rapid-acting secretagogues), reduce hepatic glucose production (biguanides), delay digestion and absorption of intestinal carbohydrate (alpha-glucosidase inhibitors) or improve insulin action (thiazolidinediones). This review is also focused on the newer therapeutically approaches such as incretin-based therapies, bariatric surgery, stem cells and other emerging therapies that promise to further extend the options available. Gene-based therapies are among the most promising emerging alternatives to conventional treatments. Some of these therapies rely on genetic modification of non-differentiated cells to express pancreatic endocrine developmental factors, promoting differentiation of non-endocrine cells into β-cells, enabling synthesis and secretion of insulin in a glucose-regulated manner. Alternative therapies based on gene silencing using vector systems to deliver interference RNA to cells (i.e. against VEGF in diabetic retinopathy) are also a promising therapeutic option for the treatment of several diabetic complications. In conclusion, treatment of diabetes faces now a new era that is characterized by a variety of innovative therapeutic approaches that will improve quality-life and allow personalized therapy-planning in the near future.
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Affiliation(s)
- Cristina M. Sena
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Subunit 1, polo 3, Azinhaga de Santa Comba, Celas, 3000-354 Coimbra, Portugal
- IBILI, University of Coimbra, Coimbra, Portugal
| | - Carla F. Bento
- IBILI, University of Coimbra, Coimbra, Portugal
- Centre of Ophthalmology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paulo Pereira
- IBILI, University of Coimbra, Coimbra, Portugal
- Centre of Ophthalmology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Raquel Seiça
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Subunit 1, polo 3, Azinhaga de Santa Comba, Celas, 3000-354 Coimbra, Portugal
- IBILI, University of Coimbra, Coimbra, Portugal
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Interactions of gastrointestinal peptides: ghrelin and its anorexigenic antagonists. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20798884 PMCID: PMC2925274 DOI: 10.1155/2010/817457] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 10/13/2009] [Accepted: 10/19/2009] [Indexed: 12/21/2022]
Abstract
Food intake behaviour and energy homeostasis are strongly regulated by a complex system of humoral factors and nerval structures constituting the brain-gut-axis. To date the only known peripherally produced and centrally acting peptide that stimulates food intake is ghrelin, which is mainly synthesized in the stomach. Recent data indicate that the orexigenic effect of ghrelin might be influenced by other gastrointestinal peptides such as cholecystokinin (CCK), bombesin, desacyl ghrelin, peptide YY (PYY), as well as glucagon-like peptide (GLP). Therefore, we will review on the interactions of ghrelin with several gastrointestinal factors known to be involved in appetite regulation in order to elucidate the interdependency of peripheral orexigenic and anorexigenic peptides in the control of appetite.
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Kalra SP. Central leptin gene therapy ameliorates diabetes type 1 and 2 through two independent hypothalamic relays; a benefit beyond weight and appetite regulation. Peptides 2009; 30:1957-63. [PMID: 19647774 PMCID: PMC2755606 DOI: 10.1016/j.peptides.2009.07.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 01/12/2023]
Abstract
Although its role in energy homeostasis is firmly established, the evidence accumulated over a decade linking the adipocyte leptin-hypothalamus axis in the pathogenesis of diabetes mellitus has received little attention in the contemporary thinking. In this context various lines of evidence are collated here to show that (1) under the direction of leptin two independent relays emanating from the hypothalamus restrain insulin secretion from the pancreas and mobilize peripheral organs--liver, skeletal muscle and brown adipose tissue--to upregulate glucose disposal, and (2), leptin insufficiency in the hypothalamus produced by either leptinopenia or restriction of leptin transport across the blood brain barrier due to hyperleptinemia of obesity and aging, initiate antecedent pathophysiological sequalae of diabetes type 1 and 2. Further, we document here the efficacy of leptin replenishment in vivo, especially by supplying it to the hypothalamus with the aid of gene therapy, in preventing the antecedent pathophysiological sequalae--hyperinsulinemia, insulin resistance and hyperglycemia--in various animal models and clinical paradigms of diabetes type 1 and 2 with or without attendant obesity. Overall, the new insights on the long-lasting antidiabetic potential of two independent hypothalamic relays engendered by central leptin gene therapy and the preclinical safety indicators in rodents warrant further validation in subhuman primates and humans.
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Affiliation(s)
- Satya P Kalra
- Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, PO Box 100244, Gainesville, FL 32610-0244, United States.
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36
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Kojima S, Asakawa A, Amitani H, Sakoguchi T, Ueno N, Inui A, Kalra SP. Central leptin gene therapy, a substitute for insulin therapy to ameliorate hyperglycemia and hyperphagia, and promote survival in insulin-deficient diabetic mice. Peptides 2009; 30:962-6. [PMID: 19428774 DOI: 10.1016/j.peptides.2009.01.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 12/22/2022]
Abstract
Long-term benefits of central leptin gene therapy in insulin-deficient diabetes are not known despite its therapeutic effects in obesity animal models such as ob/ob and diet-induced obese mice. Adult male mice were injected intraperitoneally with streptozotocin (STZ, 200mg/kg) to induce insulitis. A week later, only diabetic STZ-pretreated mice (blood glucose >350 mg/dl) received intracerebroventricularly (icv) an injection of recombinant adeno-associated virus vector (rAAV) encoding either green fluorescent protein (control), or leptin gene (rAAV-lep). Body weight (BW), food intake, blood glucose, insulin and survival rate responses were monitored post-icv injection at regular intervals for 52 weeks. The STZ pre-injected diabetic mice remained hyperphagic, gradually lost BW and died by week 6 after receiving control vector. In marked contrast, injection of rAAV-lep to raise hypothalamic leptin levels, rescued the STZ-pretreated mice from early mortality, gradually curbed hyperphagia to normalize intake by week 20, and maintained BW at significantly lower than the control range. Blood glucose levels in these mice started to recede dramatically by week 2-3 to normalize by week 8, and euglycemia was sustained during the remaining course of the experiment. rAAV-lep injected mice did not exhibit any discernible untoward gross behavioral changes and diabetic complications and showed a partial return of pancreatic beta-cell function. These results show for the first time that one time central leptin gene therapy is effective and durable in reinstating euglycemia and energy homeostasis for extended periods in the absence of insulin.
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Affiliation(s)
- Shinya Kojima
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Yin X, Li Y, Xu G, An W, Zhang W. Ghrelin fluctuation, what determines its production? Acta Biochim Biophys Sin (Shanghai) 2009; 41:188-97. [PMID: 19280057 DOI: 10.1093/abbs/gmp001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ghrelin, a 28 amino acid gut brain peptide, acts as an endogenous ligand for its receptor, the growth hormone secretagogue receptor, to exercise a variety of functions ranging from stimulation of growth hormone secretion, regulation of appetite and energy metabolism, and cell protection to modulation of inflammation. This review summarizes the advance in the regulation of ghrelin expression and secretion. We introduce the structure of ghrelin promoter, the processing and modification of ghrelin precursor, and the regulation mechanism in these processes. Then we discuss factors found to be important in the regulation of ghrelin production, including nutrients, hormones, and autonomic nervous system. Finally, we outline the alteration in the level of ghrelin in certain physiological and pathological status.
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Affiliation(s)
- Xuefeng Yin
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100191, China
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Iwaniec UT, Dube MG, Boghossian S, Song H, Helferich WG, Turner RT, Kalra SP. Body mass influences cortical bone mass independent of leptin signaling. Bone 2009; 44:404-12. [PMID: 19095090 PMCID: PMC3522417 DOI: 10.1016/j.bone.2008.10.058] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 10/01/2008] [Accepted: 10/31/2008] [Indexed: 11/19/2022]
Abstract
Obesity in humans is associated with increased bone mass. Leptin, a hormone produced by fat cells, functions as a sentinel of energy balance, and may mediate the putative positive effects of body mass on bone. We performed studies in male C57Bl/6 wild type (WT) and leptin-deficient ob/ob mice to determine whether body mass gain induced by high fat intake increases bone mass and, if so, whether this requires central leptin signaling. The relationship between body mass and bone mass and architecture was evaluated in 9-week-old and 24-week-old WT mice fed a regular mouse diet. Femora and lumbar vertebrae were analyzed by micro computed tomography. In subsequent studies, slowly and rapidly growing ob/ob mice were injected in the hypothalamus with a recombinant adeno-associated virus containing the leptin gene (rAAV-lep) or a control vector, rAAV-GFP (green fluorescent protein). The mice were maintained on a regular control diet for 5 or 7 weeks and then subdivided into groups and either continued on the control diet or fed a high fat diet (45% of kcal from fat) for 8 weeks. In the WT mice, femoral and vertebral bone mass was positively correlated with body mass (Pearson's r=0.65-0.88 depending on endpoint). rAAV-lep therapy dramatically decreased body mass (-61%) but increased femur length. However, in the distal femur and lumbar vertebra, rAAV-lep therapy reduced cancellous bone volume/tissue volume, trabecular number and trabecular thickness, and increased trabecular spacing. The high fat diet increased body mass, irrespective of vector treatment. Total femur bone volume, length, cross-sectional volume, and cortical volume and thickness were increased in mice with increased body mass, independent of rAAV treatment. In the distal femur, increased body mass had no effect on cancellous architecture and there were no vector x body mass interactions. In WT mice, increased body mass resulted in increased (+33%) vertebral cancellous bone volume/tissue volume. Increased body mass had minimal independent effect on cancellous vertebral bone mass in ob/ob mice. Taken together, these findings suggest that increased body mass has a positive effect on femur cortical bone mass that is independent of leptin signaling.
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Affiliation(s)
- U T Iwaniec
- Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331, USA.
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Kalra SP. Disruption in the leptin-NPY link underlies the pandemic of diabetes and metabolic syndrome: new therapeutic approaches. Nutrition 2009; 24:820-6. [PMID: 18725078 DOI: 10.1016/j.nut.2008.06.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Accepted: 06/11/2008] [Indexed: 12/11/2022]
Abstract
Multidisciplinary research from my and my colleagues' laboratory has shown that disruption at various levels of leptin signaling to the interactive hypothalamic network of neuropeptide Y (NPY) and cohorts contributes to the antecedent pathophysiologic sequelae of the disease cluster of the metabolic syndrome. Disruptions in NPY signaling due to high or low abundance of NPY and cognate receptors dysregulate the homeostatic milieu to promote hyperinsulinemia, hyperglycemia, fat accrual, and overt diabetes. Hyperleptinemia induced by consumption of energy-rich diets inhibits leptin transport across the blood-brain barrier and thereby produces leptin insufficiency in the hypothalamus. Sustained leptin insufficiency results in loss of hypothalamic restraint on pancreatic insulin secretion and diminished glucose metabolism and energy expenditure. This chain of events culminates in hyperinsulinemia, hyperglycemia, and diabetes. Our recent studies have shown that increasing the supply of leptin centrally by gene therapy reinstates the restraint on hypothalamic NPY signaling and ameliorates diabetes and the attendant disease cluster of the metabolic syndrome. Thus, newer therapies that would enhance leptin transport across the blood-brain barrier in a timely manner or reinstate leptin restraint on NPY signaling through central leptin gene therapy or pharmacologically with leptin mimetics are likely to curtail the pathophysiologic sequelae of diabetes and related ailments of the metabolic syndrome.
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Affiliation(s)
- Satya P Kalra
- Department of Neuroscience, University of Florida, McKnight Brain Institute, Gainesville, Florida, USA.
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40
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Puglisi MJ, Mutungi G, Brun PJ, McGrane MM, Labonte C, Volek JS, Fernandez ML. Raisins and walking alter appetite hormones and plasma lipids by modifications in lipoprotein metabolism and up-regulation of the low-density lipoprotein receptor. Metabolism 2009; 58:120-8. [PMID: 19059539 DOI: 10.1016/j.metabol.2008.08.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Accepted: 08/13/2008] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the effects of consuming raisins, increasing steps walked, or a combination of these interventions on lipoprotein metabolism and appetite hormones by assessing plasma apolipoprotein concentrations, cholesterol ester transfer protein activity, low-density lipoprotein (LDL) receptor messenger RNA (mRNA) abundance, and plasma ghrelin and leptin concentrations. Thirty-four subjects (17 men and 17 postmenopausal women) were matched for weight and sex and randomly assigned to consume 1 cup raisins per day (RAISIN), increase the amount of steps walked per day (WALK), or a combination of both interventions (RAISIN + WALK). The subjects completed a 2-week run-in period, followed by a 6-week intervention. Ribonucleic acid was extracted from mononuclear cells, and LDL receptor mRNA abundance was quantified by use of reverse transcriptase polymerase chain reaction. Plasma apolipoproteins were measured by Luminex (Austin, TX) technology. Apoproteins A-1, B, C-II, and E and cholesterol ester transfer protein activity were not altered for any of the groups. In contrast, apolipoprotein C-III was significantly decreased by 12.3% only in the WALK group (P < .05). Low-density lipoprotein receptor mRNA abundance was increased for all groups after the intervention (P < .001). There was a significant group effect for plasma leptin (P = .026). Plasma concentrations increased for RAISIN and RAISIN + WALK. Similarly, plasma ghrelin concentrations were elevated postintervention for both groups consuming raisins (P < .05). These data suggest that walking and raisin consumption decrease plasma LDL cholesterol by up-regulating the LDL receptor and that raisin consumption may reduce hunger and affect dietary intake by altering hormones influencing satiety.
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Affiliation(s)
- Michael J Puglisi
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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41
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Akki A, Seymour AML. Western diet impairs metabolic remodelling and contractile efficiency in cardiac hypertrophy. Cardiovasc Res 2008; 81:610-7. [PMID: 19028723 DOI: 10.1093/cvr/cvn316] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AIMS Metabolic remodelling in cardiac hypertrophy is underscored by a reduction in fatty acid (FA) oxidation. We tested whether this decline in FA oxidation in the presence of enhanced FA supply may predispose the hypertrophied myocardium to lipid accumulation, functional deterioration, and eventually heart failure. METHODS and results Left ventricular hypertrophy was induced surgically in Sprague-Dawley rats by inter-renal aortic constriction. Rats were fed a Western diet (WD, 45% kcal from lipids) or standard diet (SD, 12% kcal from fat) for 9 weeks post-surgery. Hearts were perfused in the isovolumic mode with a physiological mixture of substrates including 5 mM 1-(13)C glucose, 1 mM 3-(13)C lactate, and 0.3 mM U-(13)C palmitate, and cardiac function was monitored. Real-time PCR was used to determine transcript levels of peroxisome proliferator-activated receptor-alpha (PPARalpha) and PPARalpha-regulated metabolic enzymes. Palmitate oxidation and PPARalpha-regulated gene expression were markedly reduced in the hypertrophied myocardium of rats fed SD. However, 9 weeks of WD normalized both palmitate oxidation and PPARalpha-regulated gene expression but significantly increased glucose and lactate oxidation in the hypertrophied hearts. This was accompanied by cardiac triglyceride accumulation and a decline in ventricular function despite an increase in oxygen consumption. CONCLUSION These results highlight that WD-induced dysregulation of FA metabolism has deleterious functional consequences in cardiac hypertrophy.
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Affiliation(s)
- Ashwin Akki
- Department of Biological Sciences, Hull York Medical School, University of Hull, Cottingham Road, Kingston-upon-Hull HU6 7RX, UK
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42
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Singh MK, Elefteriou F, Karsenty G. Cocaine and amphetamine-regulated transcript may regulate bone remodeling as a circulating molecule. Endocrinology 2008; 149:3933-41. [PMID: 18450969 PMCID: PMC2488246 DOI: 10.1210/en.2008-0109] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cocaine- and amphetamine-regulated transcript (CART) is one of the two known mediators of the leptin regulation of bone mass. Cart is expressed in both the brain and peripheral tissues such as the pituitary gland and the pancreatic islets. Cart(-/-) mice present a low bone mass phenotype due to an isolated increase in osteoclast number. In an effort to rescue their bone phenotype, we delivered recombinant CART in the third ventricle of the mutant mice but never recorded any improvement of the low bone mass, although this procedure could affect fat pad mass. In contrast, transgenic mice harboring a 2-fold increase in CART circulating level display a high bone mass due to an isolated decrease in osteoclast number and could rescue the low bone mass phenotype of the Cart(-/-) mice. Thus, our results suggest that in its capacity of a regulator of bone remodeling, CART may act more as a circulating molecule than a neuropeptide.
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Affiliation(s)
- Manvendra K Singh
- Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, 701 West 168th Street, New York, New York 10032, USA
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43
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Dube MG, Torto R, Kalra SP. Increased leptin expression selectively in the hypothalamus suppresses inflammatory markers CRP and IL-6 in leptin-deficient diabetic obese mice. Peptides 2008; 29:593-8. [PMID: 18325632 PMCID: PMC2291149 DOI: 10.1016/j.peptides.2008.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 01/03/2008] [Accepted: 01/04/2008] [Indexed: 01/30/2023]
Abstract
Low-grade systemic inflammation, as indicated by increased circulating levels of inflammatory markers CRP and IL-6, is linked to increased risks for cardiovascular diseases (CVD) and diabetes mellitus in obese subjects. Whereas hyperleptinemia in obesity are associated with increased CRP and IL-6 release, the hypothalamic versus peripheral site of leptin action has not been ascertained. The effects of increased leptin supply selectively in the hypothalamus by gene therapy on pro-inflammatory CRP and IL-6 levels and on markers of diabetes in the circulation of ob/ob mice displaying either age-related or dietary obesity were assessed. A recombinant adeno-associated viral vector encoding either green-fluorescent protein (control) or leptin gene was injected intracerebroventricularly. Five weeks later, one-half of each of the vector groups was switched to high-fat diet consumption and the other half continued to consume regular low-fat chow diet. Body weight and visceral white adipose tissue were drastically reduced and hyperinsulinemia and hyperglycemia were abrogated by leptin gene therapy, independent of the dietary fat content. The elevated plasma CRP and IL-6 levels seen in obese ob/ob mice receiving the control vector, regardless of the fat content of the diet, were markedly suppressed by increased hypothalamic leptin in both groups. The results show for the first time that leptin deficiency elevates and reinstatement of leptin selectively in the hypothalamus suppresses the release of pro-inflammatory biomarkers, a response likely to alleviate CVD associated with obesity.
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Affiliation(s)
- Michael G. Dube
- Department of Physiology and Functional Genomics, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Rita Torto
- Department of Physiology and Functional Genomics, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Satya P. Kalra
- Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL
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van den Hoek AM, Teusink B, Voshol PJ, Havekes LM, Romijn JA, Pijl H. Leptin deficiency per se dictates body composition and insulin action in ob/ob mice. J Neuroendocrinol 2008; 20:120-7. [PMID: 18081560 DOI: 10.1111/j.1365-2826.2007.01626.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Obese humans are often insulin- and leptin resistant. Since leptin can affect glucose metabolism, it is conceivable that a lack of leptin signal transduction contributes to insulin resistance. It remains unclear whether leptin affects glucose metabolism via peripheral and/or central mechanistic routes. In the present study, we aimed: (i) to determine the relative contributions of lack of leptin signal transduction and adiposity to insulin resistance and (ii) to establish the impact of central leptin action on glucose metabolism. To address the first point, ob/ob mice were subjected to severe calorie restriction, so that their body weight became similar to that of wild-type mice. Insulin sensitivity was measured in obese ob/ob, lean (food restricted) ob/ob and lean, weight-matched wild-type mice. To address the second point, leptin (or vehicle) was i.c.v. infused to the lateral cerebral ventricle of ob/ob mice and insulin sensitivity was determined. Hyperinsulinaemic euglyceamic clamps were used to quantify insulin sensitivity. Food restriction barely affected body composition, although it profoundly curtailed body weight. Insulin suppressed hepatic glucose production (HGP) to a greater extent in lean ob/ob than in obese ob/ob mice, but its impact remained considerably less than in wild-type mice (% suppression: 11.8 +/- 8.9 versus 1.3 +/- 1.1 versus 56.6 +/- 13.0%/nmol, for lean, obese ob/ob and wild-type mice, respectively; P < 0.05). The insulin-mediated glucose disposal (GD) of lean ob/ob mice was also in between that of obese ob/ob and wild-type mice (37.5 +/- 21.4 versus 25.1 +/- 14.6 versus 59.6 +/- 17.3 mumol/min/kg/nmol of insulin, respectively; P < 0.05 wild-type versus obese ob/ob mice). Leptin infusion acutely enhanced both hepatic insulin sensitivity (insulin-induced inhibition of HGP) and insulin-mediated GD (9.1 +/- 2.4 versus 5.0 +/- 2.7%/nmol of insulin, and 25.6 +/- 5.6 versus 13.6 +/- 4.8 mumol/min/kg/nmol of insulin, respectively; P < 0.05 for both comparisons) in ob/ob mice. Both a lack of leptin signals and adiposity may contribute to insulin resistance in obese individuals. Diminution of central leptin signalling can critically affect glucose metabolism in these individuals.
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Affiliation(s)
- A M van den Hoek
- TNO-Quality of Life, Gaubius Laboratory, Leiden, The Netherlands.
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45
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Central leptin insufficiency syndrome: an interactive etiology for obesity, metabolic and neural diseases and for designing new therapeutic interventions. Peptides 2007; 29:127-38. [PMID: 18053615 DOI: 10.1016/j.peptides.2007.10.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 10/17/2007] [Accepted: 10/18/2007] [Indexed: 01/10/2023]
Abstract
This review critically reappraises recent scientific evidence concerning central leptin insufficiency versus leptin resistance formulations to explain metabolic and neural disorders resulting from subnormal or defective leptin signaling in various sites in the brain. Research at various fronts to unravel the complexities of the neurobiology of leptin is surveyed to provide a comprehensive account of the neural and metabolic effects of environmentally imposed fluctuations in leptin availability at brain sites and the outcome of newer technology to restore leptin signaling in a site-specific manner. The cumulative new knowledge favors a unified central leptin insufficiency syndrome over the, in vogue, central resistance hypothesis to explain the global adverse impact of deficient leptin signaling in the brain. Furthermore, the leptin insufficiency syndrome delineates a novel role of leptin in the hypothalamus in restraining rhythmic pancreatic insulin secretion while concomitantly enhancing glucose metabolism and non-shivering thermogenic energy expenditure, sequelae that would otherwise promote fat accrual to store excess energy resulting from consumption of energy-enriched diets. A concerted effort should now focus on development of newer technologies for delivery of leptin or leptin mimetics to specifically target neural pathways for remediation of diverse ailments encompassing the central leptin insufficiency syndrome.
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46
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Bueno AA, Oyama LM, de Oliveira C, Pisani LP, Ribeiro EB, Silveira VLF, Oller do Nascimento CM. Effects of different fatty acids and dietary lipids on adiponectin gene expression in 3T3-L1 cells and C57BL/6J mice adipose tissue. Pflugers Arch 2007; 455:701-9. [PMID: 17717684 DOI: 10.1007/s00424-007-0330-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 06/27/2007] [Accepted: 07/25/2007] [Indexed: 10/22/2022]
Abstract
Obesity is positively correlated to dietary lipid intake, and the type of lipid may play a causal role in the development of obesity-related pathologies. A major protein secreted by adipose tissue is adiponectin, which has antiatherogenic and antidiabetic properties. The aim of this study was to evaluate the effects of four different high-fat diets (enriched with soybean oil, fish oil, coconut oil, or lard) on adiponectin gene expression and secretion by the white adipose tissue (WAT) of mice fed on a selected diet for either 2 (acute treatment) or 60 days (chronic treatment). Additionally, 3T3-L1 adipocytes were treated for 48 h with six different fatty acids: palmitic, linoleic, eicosapentaenoic (EPA), docosahexaenoic (DHA), lauric, or oleic acid. Serum adiponectin concentration was reduced in the soybean-, coconut-, and lard-enriched diets in both groups. Adiponectin gene expression was lower in retroperitoneal WAT after acute treatment with all diets. The same reduction in levels of adiponectin gene expression was observed in epididymal adipose tissue of animals chronically fed soybean and coconut diets and in 3T3-L1 cells treated with palmitic, linoleic, EPA, and DHA acids. These results indicate that the intake of certain fatty acids may affect serum adiponectin levels in mice and adiponectin gene expression in mouse WAT and 3T3-L1 adipocytes. The effects appear to be time dependent and depot specific. It is postulated that the downregulation of adiponectin expression by dietary enrichment with soybean oil or coconut oil may contribute to the development of insulin resistance and atherosclerosis.
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Affiliation(s)
- Allain Amador Bueno
- Department of Physiology, Campus Sao Paulo, São Paulo Federal University, São Paulo, Brazil
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Wiater MF, Hudson BD, Virgin Y, Ritter S. Protein appetite is increased after central leptin-induced fat depletion. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1468-73. [PMID: 17596325 DOI: 10.1152/ajpregu.00322.2007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Leptin reduces body fat selectively, sparing body protein. Accordingly, during chronic leptin administration, food intake is suppressed, and body weight is reduced until body fat is depleted. Body weight then stabilizes at this fat-depleted nadir, while food intake returns to normal caloric levels, presumably in defense of energy and nutritional homeostasis. This model of leptin treatment offers the opportunity to examine controls of food intake that are independent of leptin's actions, and provides a window for examining the nature of feeding controls in a "fatless" animal. Here we evaluate macronutrient selection during this fat-depleted phase of leptin treatment. Adult, male Sprague-Dawley rats were maintained on standard pelleted rodent chow and given daily lateral ventricular injections of leptin or vehicle solution until body weight reached the nadir point and food intake returned to normal levels. Injections were then continued for 8 days, during which rats self-selected their daily diet from separate sources of carbohydrate, protein, and fat. Macronutrient choice differed profoundly in leptin and control rats. Leptin rats exhibited a dramatic increase in protein intake, whereas controls exhibited a strong carbohydrate preference. Fat intake did not differ between groups at any time during the 8-day test. Despite these dramatic differences in macronutrient selection, total daily caloric intake did not differ between groups except on day 2. Thus controls of food intake related to ongoing metabolic and nutritional requirements may supersede the negative feedback signals related to body fat stores.
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Affiliation(s)
- Michael F Wiater
- Programs in Neuroscience, Washington State Univ., Pullman, WA 99164-6520, USA
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48
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Iwaniec UT, Boghossian S, Lapke PD, Turner RT, Kalra SP. Central leptin gene therapy corrects skeletal abnormalities in leptin-deficient ob/ob mice. Peptides 2007; 28:1012-9. [PMID: 17346852 PMCID: PMC1986832 DOI: 10.1016/j.peptides.2007.02.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 01/29/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
Skeletal growth is tightly coupled to energy balance via complex and incompletely understood mechanisms. Leptin-deficient ob/ob mice are obese and develop multiple pathologies associated with the metabolic syndrome. Additionally, ob/ob mice have skeletal abnormalities. The objective of this study was to evaluate the effects of leptin deficiency and long duration selective central leptin repletion via recombinant adeno-associated virus-leptin (rAAV-lep) gene therapy on bone in growing ob/ob mice. The ob/ob mice were injected in the hypothalamus with either rAAV-lep or rAAV-GFP (control vector). Treated ob/ob and untreated wild-type (WT) mice were then maintained on a normal diet for 15 weeks. In a second experiment, similarly treated mice along with a group of pair-fed mice were maintained for 30 weeks. Leptin was not detected in blood of either rAAV-lep- or rAAV-GFP-treated mice although rAAV-lep-treated mice displayed leptin transgene expression in the hypothalamus. As expected, rAAV-lep normalized body weight and food intake. Compared to WT mice, rAAV-GFP-treated ob/ob mice had decreased femoral length (by 1.6 mm or 10%, P<0.001), decreased total femur bone volume (by 3.3 mm(3) or 19%, P<0.001), but increased cancellous bone volume in the distal femur (by 0.04 mm(3) or 60%, P<0.09) and lumbar vertebrae (by 0.26 mm(3) or 118%, P<0.001). Treatment with rAAV-lep rescued the ob/ob skeletal phenotype by increasing femoral length and total bone volume, and decreasing femoral and vertebral cancellous bone volume, so that at 15 weeks post-rAAV-lep injection the ob/ob mice no longer differed from WT mice. No further skeletal changes in either the femur or lumbar vertebra were observed at 30 weeks post-rAAV-lep administration. The results suggest that hypothalamic leptin functions as an essential permissive factor for normal bone growth.
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Affiliation(s)
- Urszula T Iwaniec
- Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331, USA.
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49
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Kalra SP, Kalra PS. To subjugate NPY is to improve the quality of life and live longer. Peptides 2007; 28:413-8. [PMID: 17215061 PMCID: PMC1839846 DOI: 10.1016/j.peptides.2006.08.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 08/09/2006] [Indexed: 10/23/2022]
Abstract
The interactive network of neuropeptide Y (NPY) and cohorts is necessary for integrating the hypothalamic regulation of appetite and energy expenditure with the endocrine and neuroendocrine systems on a daily basis. Genetic and environmental factors that produce an insufficiency of leptin restraint on NPY and cognate receptors deregulate the homeostasis to engender various life-threatening risk factors. Recent studies from our laboratory show that neurotherapy consisting of a single central administration of recombinant adeno-associated virus vector encoding the leptin gene can repress the hypothalamic NPY system for the lifetime of rodents. A major benefit of this stable tonic restraint is deceleration of pathophysiologic sequalae that shorten life span. These include suppression of weight gain, fat accumulation, circulating adipokines, amelioration of major symptoms of metabolic syndrome, improved reproduction and bone health. Thus, sustained repression of NPY signaling in the hypothalamus by leptin transgene expression can improve the quality of life and extend longevity.
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Affiliation(s)
- Satya P Kalra
- Department of Neuroscience, McKnight Brain Institute, University of Florida, PO Box 100244, Gainesville, FL 32610-0244, USA.
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50
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Boghossian S, Dube MG, Torto R, Kalra PS, Kalra SP. Hypothalamic clamp on insulin release by leptin-transgene expression. Peptides 2006; 27:3245-54. [PMID: 16962683 DOI: 10.1016/j.peptides.2006.07.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 07/24/2006] [Accepted: 07/26/2006] [Indexed: 12/15/2022]
Abstract
The effects of sustained leptin action locally in the hypothalamus on the functional link between fat accrual and insulin secretion after chronic high fat diet (HFD) consumption in leptin-deficient ob/ob mice, and on the post-prandial insulin response in rats consuming regular chow diet (RCD), was examined in this study. A single intracerebroventricular (icv) injection of recombinant adeno-associated virus vector encoding leptin gene (rAAV-lep) enhanced hypothalamic leptin-transgene expression in ob/ob mice consuming RCD and suppressed the time-related weight gain and fat accumulation concomitant with abrogation of hyperinsulinemia and enhanced glucose tolerance. This increased hypothalamic leptin-transgene expression continued to impose insulinopenia and increased glucose tolerance but was ineffective in suppressing weight gain and fat accumulation after these mice were switched to chronic HFD consumption. A similar icv rAAV-lep pretreatment in rats consuming RCD markedly attenuated the post-prandial rise in insulin release concomitant with suppressed weight and fat depots. These results show for the first time that a sustained hypothalamic leptin action can stably clamp pancreatic insulin secretion independent of the status of fat accrual engendered by diets of varying caloric enrichment. Thus, the efficacy of increased leptin afferent signaling in the hypothalamus to persistently restrain pancreatic insulin release and insulin resistance can be explored as an adjunct therapeutic modality to alleviate pathophysiological derrangements that confer type 2 diabetes.
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Affiliation(s)
- Stéphane Boghossian
- Department of Neuroscience, University of Florida, McKnight Brain Institute, PO Box 100244, Gainesville, FL 32610-0244, USA
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