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Cordeiro MM, Ribeiro RA, Bubna PB, Almeida AC, Laginski TRF, Franco GCN, Scomparin DX. Physical exercise attenuates obesity development in Western‐diet fed obese rats, independently of vitamin D supplementation. Clin Exp Pharmacol Physiol 2022; 49:633-642. [DOI: 10.1111/1440-1681.13637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/12/2021] [Accepted: 11/19/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Maiara Mikuska Cordeiro
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
| | - Rosane Aparecida Ribeiro
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
| | - Patrícia Biscaia Bubna
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
| | - Any Caroline Almeida
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
| | | | - Gilson César Nobre Franco
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
| | - Dionízia Xavier Scomparin
- General Biology Department, Biologic Science and Health Sector State University of Ponta Grossa Ponta Grossa Puerto Rico Brazil
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Cordeiro MM, Biscaia PB, Brunoski J, Ribeiro RA, Franco GCN, Scomparin DX. Vitamin D supplementation decreases visceral adiposity and normalizes leptinemia and circulating TNF-α levels in western diet-fed obese rats. Life Sci 2021; 278:119550. [PMID: 33932442 DOI: 10.1016/j.lfs.2021.119550] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 11/25/2022]
Abstract
AIMS Vitamin (Vit) D regulates various organic processes, including adipose tissue morphofunction and lipid metabolism. Studies indicate that Vit D bioavailability is reduced in obesity, which could contribute to obesity development; however, the effects of Vit D supplementation on increased adiposity in western diet (WD)-obese rats (an experimental model that better resembles the obesogenic human obesity condition) have not been studied, to date. Thus, we hypothesized that Vit D supplementation following the induction of obesity in WD rats might reduce their body weight (BW) and adiposity. MAIN METHODS Male Wistar rats were fed on a standard chow [control (CTL) group] or a WD to induce obesity (WD group), from 21 to 59 days of age. Subsequently, from 60 to 90-days, half of the CTL and of the WD rats were randomly submitted, or not, to oral Vit D supplementation (CTL-VD and WD-VD groups, respectively). KEY FINDINGS At 91 days of age, WD rats were obese, displaying higher abdominal circumference and white fat stores, dyslipidemia, hyperleptinemia and greater plasma levels of tumor necrosis factor (TNF)-α. Vit D supplementation decreased BW gain, abdominal fat deposition and ameliorated the plasma lipid profile in WD-VD rats. These effects were accompanied by reductions in leptinemia and in circulating TNF-α levels in these rodents. SIGNIFICANCE Vit D supplementation, following the induction of obesity, may represent a good strategy to attenuate BW gain and abdominal adiposity, and ameliorate the plasma lipid profile in WD rats. These effects may be mediated, at least in part, by reductions in circulating levels of leptin and TNF-α.
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Affiliation(s)
- Maiara Mikuska Cordeiro
- Departamento de Biologia Geral, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Patrícia Bubna Biscaia
- Departamento de Farmácia, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Janaini Brunoski
- Departamento de Enfermagem e Saúde Pública, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Rosane Aparecida Ribeiro
- Departamento de Biologia Geral, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Gilson César Nobre Franco
- Departamento de Biologia Geral, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Dionizia Xavier Scomparin
- Departamento de Biologia Geral, Setor de Ciências Biológicas e da Saúde, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil.
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Alula KM, Biltz R, Xu H, Garver H, Laimon-Thomson EL, Fink GD, Galligan JJ. Effects of high-fat diet on sympathetic neurotransmission in mesenteric arteries from Dahl salt-sensitive rat. Auton Neurosci 2019; 222:102599. [PMID: 31731103 DOI: 10.1016/j.autneu.2019.102599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/18/2019] [Accepted: 10/29/2019] [Indexed: 12/19/2022]
Abstract
Obesity hypertension is driven by sympathetic neurotransmission to the heart and blood vessels. We tested the hypothesis that high-fat diet (HFD)-induced hypertension is driven by sympathetic neurotransmission to mesenteric arteries (MA) in male but not female Dahl salt-sensitive (Dahl ss) rat. Rats were fed a control diet (CD; 10 kcal% from fat) or HFD (60 kcal% from fat) beginning at 3 weeks (wk) of age; measurements were made at 10-, 17- and 24-wk. Body weight increased with HFD, age and sex. Mean arterial pressure (MAP) was higher in HFD versus CD rats from both sexes at 17- and 24-wk. MA constriction measured using pressure myography, and electrical field stimulation (EFS, 0.2-30 Hz) was greater in HFD versus CD in males at 17-wk; this was not due to changes in α2 autoreceptor or norepinephrine transporter (NET) function. Prazosin (α1-AR antagonist) and suramin (P2 receptor antagonist) inhibited neurogenic MA constriction equally in all groups. Arterial reactivity to exogenous norepinephrine (NE; 10-8 - 10-5 M) was lower in HFD versus CD at 10-wk in males. Female MA reactivity to exogenous ATP was lower at 24-weeks compared to earlier time points. HFD did not affect tyrosine hydroxylase (TH) or the vesicular nucleotide transporter (VNUT) nerve density in MA from both sexes. NE content was lower in MA but higher in plasma at 24-wk compared to 10- and 17-wk in both sexes. In conclusion, HFD-induced hypertension is not driven by increased sympathetic neurotransmission to MA in male and female Dahl ss rats.
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Affiliation(s)
- Kibrom M Alula
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Rebecca Biltz
- The Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Hui Xu
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA; The Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Hannah Garver
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Erinn L Laimon-Thomson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA; The Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - James J Galligan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA; The Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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Bazzano MV, Sarrible GB, Martinez N, Berón de Astrada M, Elia EM. Obesity alters the uterine environment before pregnancy. J Nutr Biochem 2018; 62:181-191. [PMID: 30300837 DOI: 10.1016/j.jnutbio.2018.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/03/2018] [Accepted: 09/12/2018] [Indexed: 11/30/2022]
Abstract
Obesity is a metabolic disorder that predisposes to numerous diseases and has become a major global public health concern. Cafeteria diet (CAF) is the animal model used for the study of obesity that more closely reflects Western diet habits. Previously, we described that CAF administration for 60 days induces obesity in female rats and their fetuses develop macrosomia. Given that, in our model, rats are not genetically modified and that obese mothers were fed standard chow during pregnancy, the aim of the current study was to test the hypothesis that obesity alters the intrauterine environment prior to pregnancy, and this may explain the exacerbated fetal weight gain. We found that uteri from obese rats during the estrous phase developed insulin resistance through mechanisms that involve the induction of uterine hypoxia and the down-regulation of the insulin receptor gene. Moreover, uterine cell proliferation was induced by obesity concomitantly with the reduction in the uterine contractile response to a β2 AR agonist, salbutamol, and this may be consequence of the down-regulation in the uterine β2 AR expression. We conclude that CAF-induced obesity alters the uterine environment in rats during the estrous phase and may cause the fetal macrosomia previously described by us in obese animals. The lower sensitivity of the uterus to a relaxation stimulus (salbutamol) is not a minor fact given that for implantation to occur the uterus must be relaxed for embryo nidation. Thus, the alteration in the uterine quiescence may impair implantation and, consequently, the foregoing pregnancy.
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Affiliation(s)
- María Victoria Bazzano
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales (FCEN), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA-Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Gisela Belén Sarrible
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales (FCEN), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA-Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina; UBA, FCEN, Departamento de Biodiversidad y Bilogía Experimental, Buenos Aires, Argentina
| | - Nora Martinez
- UBA, Facultad de Medicina, Buenos Aires, Argentina; CONICET-UBA- Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO), Buenos Aires, Argentina
| | - Martín Berón de Astrada
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales (FCEN), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA-Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina; UBA, FCEN, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina
| | - Evelin Mariel Elia
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales (FCEN), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA-Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina; UBA, FCEN, Departamento de Biodiversidad y Bilogía Experimental, Buenos Aires, Argentina.
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Leposavić GM, Pilipović IM. Intrinsic and Extrinsic Thymic Adrenergic Networks: Sex Steroid-Dependent Plasticity. Front Endocrinol (Lausanne) 2018; 9:13. [PMID: 29441042 PMCID: PMC5797573 DOI: 10.3389/fendo.2018.00013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/11/2018] [Indexed: 12/30/2022] Open
Abstract
The thymus is sexually differentiated organ providing microenvironment for T-cell precursor differentiation/maturation in the major histocompatibility complex-restricted self-tolerant T cells. With increasing age, the thymus undergoes involution leading to the decline in efficacy of thymopoiesis. Noradrenaline from thymic nerve fibers and "(nor)adrenergic" cells is involved in the regulation of thymopoiesis. In rodents, noradrenaline concentration in thymus and adrenoceptor (AR) expression on thymic cells depend on sex and age. These differences are suggested to be implicated in the development of sexual diergism and the age-related decline in thymopoiesis. The programming of both thymic sexual differentiation and its involution occurs during the critical early perinatal period and may be reprogrammed during peripubertal development. The thymic (re)programming is critically dependent on circulating levels of gonadal steroids. Although the underlying molecular mechanisms have not yet been elucidated fully, it is assumed that the gonadal steroid action during the critical perinatal/peripubertal developmental periods leads to long-lasting changes in the efficacy of thymopoiesis partly through (re)programming of "(nor)adrenergic" cell networks and AR expression on thymic cells.
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Affiliation(s)
- Gordana Momčilo Leposavić
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
- *Correspondence: Gordana Momčilo Leposavić,
| | - Ivan M. Pilipović
- Immunology Research Centre “Branislav Janković”, Institute of Virology, Vaccines and Sera “Torlak”, Belgrade, Serbia
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Shi Z, Brooks VL. Leptin differentially increases sympathetic nerve activity and its baroreflex regulation in female rats: role of oestrogen. J Physiol 2014; 593:1633-47. [PMID: 25398524 DOI: 10.1113/jphysiol.2014.284638] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/08/2014] [Indexed: 01/30/2023] Open
Abstract
Obesity and hypertension are commonly associated, and activation of the sympathetic nervous system is considered to be a major contributor, at least in part due to the central actions of leptin. However, while leptin increases sympathetic nerve activity (SNA) in males, whether leptin is equally effective in females is unknown. Here, we show that intracerebroventricular (i.c.v.) leptin increases lumbar (LSNA) and renal (RSNA) SNA and baroreflex control of LSNA and RSNA in α-chloralose anaesthetized female rats, but only during pro-oestrus. In contrast, i.c.v. leptin increased basal and baroreflex control of splanchnic SNA (SSNA) and heart rate (HR) in rats in both the pro-oestrus and dioestrus states. The effects of leptin on basal LSNA, RSNA, SSNA and HR were similar in males and pro-oestrus females; however, i.c.v. leptin increased mean arterial pressure (MAP) only in males. Leptin did not alter LSNA or HR in ovariectomized rats, but its effects were normalized with 4 days of oestrogen treatment. Bilateral nanoinjection of SHU9119 into the paraventricular nucleus of the hypothalamus (PVN), to block α-melanocyte-stimulating hormone (α-MSH) type 3 and 4 receptors, decreased LSNA in leptin-treated pro-oestrus but not dioestrus rats. Unlike leptin, i.c.v. insulin infusion increased basal and baroreflex control of LSNA and HR similarly in pro-oestrus and dioestrus rats; these responses did not differ from those in male rats. We conclude that, in female rats, leptin's stimulatory effects on SNA are differentially enhanced by oestrogen, at least in part via an increase in α-MSH activity in the PVN. These data further suggest that the actions of leptin and insulin to increase the activity of various sympathetic nerves occur via different neuronal pathways or cellular mechanisms. These results may explain the poor correlation in females of SNA with adiposity, or of MAP with leptin.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, 97239, USA
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Brooks VL, Shi Z, Holwerda SW, Fadel PJ. Obesity-induced increases in sympathetic nerve activity: sex matters. Auton Neurosci 2014; 187:18-26. [PMID: 25435000 DOI: 10.1016/j.autneu.2014.11.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 11/02/2014] [Accepted: 11/08/2014] [Indexed: 01/18/2023]
Abstract
Abundant evidence obtained largely from male human and animal subjects indicates that obesity increases sympathetic nerve activity (SNA), which contributes to hypertension development. However, recent studies that included women reported that the strong relationships between muscle SNA and waist circumference or body mass index (BMI) found in men are not present in overweight and obese women. A similar sex difference in the association between adiposity and hypertension development has been identified in animal models of obesity. In this brief review, we consider two possible mechanisms for this sex difference. First, visceral adiposity, leptin, insulin, and angiotensin II have been identified as potential culprits in obesity-induced sympathoexcitation in males. We explore if these factors wield the same impact in females. Second, we consider if sex differences in vascular reactivity to sympathetic activation contribute. Our survey of the literature suggests that premenopausal females may be able to resist obesity-induced sympathoexcitation and hypertension in part due to differences in adipose disposition as well as its muted inflammatory response and reduced production of pressor versus depressor components of the renin-angiotensin system. In addition, vascular responsiveness to increased SNA may be reduced. However, more importantly, we identify the urgent need for further study, not only of sex differences per se, but also of the mechanisms that may mediate these differences. This information is required not only to refine treatment options for obese premenopausal women but also to potentially reveal new therapeutic avenues in obese men and women.
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Affiliation(s)
- Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, United States.
| | - Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, United States
| | - Seth W Holwerda
- Department of Medical Pharmacology and Physiology, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65212, United States
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65212, United States
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Rezaeian S, Moghimbeigi A, Esmailnasab N. Gender differences in risk factors of congenital hypothyroidism: an interaction hypothesis examination. Int J Endocrinol Metab 2014; 12:e13946. [PMID: 24790630 PMCID: PMC4005272 DOI: 10.5812/ijem.13946] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 08/12/2013] [Accepted: 01/05/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Several studies have demonstrated an increased risk of congenital hypothyroidism (CH) in girls in comparison to boys. OBJECTIVES The aim of this study was to determine the potential interactions that are able to change the effect of gender on congenital hypothyroidism. PATIENTS AND METHODS We conducted a matched 1:4 case-control study in Hamadan Province, western of Iran, from 2005 to 2011. Based on screening program data, neonates with TSH ≥ 10 mU/L and T4 ≤ 6.4 μg/dL were considered as congenital hypothyroidism (Cases). Cases and controls were matched regarding the year and place of birth. Data was analyzed using two different approaches including propensity score and multiple conditional logistic regression model. RESULTS A total of 277 cases and 1036 controls were included in the study. Girls accounted for 57.4% of the cases and 51.2% of controls (P = 0.065). Based on the multiple conditional logistic regressions, only the interaction of gender (girl) and birth season (summer) increased the likelihood of CH significantly (OR = 3.09; 95% CI: 1.09-8.74; P = 0.034). On the other hand, the ORs of the interaction of gender and all other factors (except for birth season) were not statistically significant in CH. CONCLUSIONS Birth season might act as an interaction that is able to increase the risk of CH in girls. Accordingly, awareness of the birth season could help policymakers who plan preventive programs to reduce the false negative results among neonates, especially girls.
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Affiliation(s)
- Shahab Rezaeian
- Department of Epidemiology, School of Health, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Abbas Moghimbeigi
- Research Center for Health Sciences, Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Nader Esmailnasab
- Kurdistan Research Center for Social Determinants of Health (KRCSDH), School of Medicine, Kurdistan University of Medical Sciences, Sanandaj, IR Iran
- Corresponding author: Nader Esmailnasab, Department of Epidemiology and Biostatistics, School of Medicine, Kurdistan University of Medical Sciences, P.O.Box:66177-13446, Sanandaj, IR Iran. Tel: +98-8716131384, Fax: +98-8716664674, E-mail:
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Leposavic G, Perisic M, Pilipovic I. Role of gonadal hormones in programming developmental changes in thymopoietic efficiency and sexual diergism in thymopoiesis. Immunol Res 2012; 52:7-19. [PMID: 22407539 DOI: 10.1007/s12026-012-8278-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is a growing body of evidence indicating the important role of the neonatal steroid milieu in programming sexually diergic changes in thymopoietic efficiency, which in rodents occur around puberty and lead to a substantial phenotypic and functional remodeling of the peripheral T-cell compartment. This in turn leads to an alteration in the susceptibility to infection and various immunologically mediated pathologies. Our laboratory has explored interdependence in the programming and development of the hypothalamo-pituitary-gonadal axis and thymus using experimental model of neonatal androgenization. We have outlined critical points in the complex process of T-cell development depending on neonatal androgen imprinting and the peripheral outcome of these changes and have pointed to underlying mechanisms. Our research has particularly contributed to an understanding of the putative role of changes in catecholamine-mediated communications in the thymopoietic alterations in adult neonatally androgenized rats.
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Affiliation(s)
- Gordana Leposavic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, 450 Vojvode Stepe, 11221 Belgrade, Serbia.
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10
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Radojević K, Kosec D, Perišić M, Pilipović I, Vidić-Danković B, Leposavić G. Neonatal androgenization affects the efficiency of β-adrenoceptor-mediated modulation of thymopoiesis. J Neuroimmunol 2011; 239:68-79. [PMID: 21940054 DOI: 10.1016/j.jneuroim.2011.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/25/2011] [Accepted: 08/31/2011] [Indexed: 01/29/2023]
Abstract
We tested the hypothesis that neonatal androgenization affects the efficacy of β-adrenoceptor (β-AR)-mediated fine tuning of thymopoiesis in adult female rats by modulating the thymic noradrenaline (NA) level and/or β-AR expression. In adult rats administered with 1000 μg testosterone enanthate at postnatal day 2 a higher density of catecholamine (CA)-synthesizing thymic cells, including thymocytes, and a rise in their CA content was found. In addition, in these animals increased thymic noradrenergic nerve fiber fluorescence intensity, reflecting their increased CA content, was detected. These changes were followed by an increase in thymic NA concentration. The rise in thymic NA content in thymic nerve fibers and cells was associated with changes in the expression of mRNA for enzymes controlling pivotal steps in NA biosynthesis (tyrosine hydroxylase, dopamine-β-hydroxylase) and inactivation (monoamine oxidase). In contrast, the thymic level of β(2)-AR mRNA on a per cell basis and the receptor surface density on thymocytes was reduced in testosterone-treated (TT) rats. As a consequence, 14-day-long treatment with propranolol, a β-AR blocker, was ineffective in modulating T-cell differentiation/maturation in TT rats. In conclusion, the study indicates the importance of the neonatal sex steroid milieu for shaping the immunomodulatory capacity of the thymic NA/β-AR signaling system in adult rats.
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Affiliation(s)
- Katarina Radojević
- Institute of Virology, Vaccines and Sera Torlak, 458 Vojvode Stepe, Belgrade, Serbia
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11
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Affiliation(s)
- Christian F Deschepper
- Experimental Cardiovascular Biology Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Quebec, Canada.
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12
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Martins ACP, Souza KLA, Shio MT, Mathias PCF, Lelkes PI, Garcia RMG. Adrenal medullary function and expression of catecholamine-synthesizing enzymes in mice with hypothalamic obesity. Life Sci 2004; 74:3211-22. [PMID: 15094322 DOI: 10.1016/j.lfs.2003.10.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Accepted: 10/14/2003] [Indexed: 12/17/2022]
Abstract
The mechanisms underlying the onset of obesity are complex and not completely understood. An imbalance of autonomic nervous system has been proposed to be a major cause of great fat deposits accumulation in hypothalamic obesity models. In this work we therefore investigated the adrenal chromaffin cells in monosodium glutamate (MSG)-treated obese female mice. Newborn mice were injected daily with MSG (4 mg/g body weight) or saline (controls) during the first five days of life and studied at 90 days of age. The adrenal catecholamine content was 56.0% lower in the obese group when compared to lean controls (P < 0.0001). Using isolated adrenal medulla we observed no difference in basal catecholamine secretion percentile between obese and lean animals. However, the percentile of catecholamine secretion stimulated by high K+ concentration was lower in the obese group. There was a decrease in the tyrosine hydroxylase enzyme expression (57.3%, P < 0.004) in adrenal glands of obese mice. Interestingly, the expression of dopamine beta-hydroxylase was also reduced (47.0%, P < 0.005). Phenylethanolamine N-methyltransferase expression was not affected. Our results show that in the MSG model, obesity status is associated with a defective adrenal chromaffin cell function. We conclude that in MSG obesity the low total catecholamine content is directly related to a decrease of key catecholamine-synthesizing enzymes, which by its turn may lead to a defective catecholamine secretion.
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Affiliation(s)
- Andréia C P Martins
- Department of Cell Biology and Genetics, State University of Maringá, Maringá, PR, Brazil
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Plut C, Ribière C, Giudicelli Y, Dausse JP. Hypothalamic leptin receptor and signaling molecule expressions in cafeteria diet-fed rats. J Pharmacol Exp Ther 2003; 307:544-9. [PMID: 12966151 DOI: 10.1124/jpet.103.054726] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although obesity is associated with a state of leptin resistance, it has been suggested that leptin may contribute to the pathogenesis of obesity-related hypertension. In previous studies, we reported that cafeteria diet feeding induces hyperleptinaemia and hyperinsulinemia in both male and female rats, with hypertension occurring only in male rats. However, when female rats were neonatally treated with testosterone (T), these animals develop hypertension when fed the cafeteria diet. These observations led us to investigate leptin signaling and some neuropeptides that are leptin targets in the hypothalamus of male, intact female, and T-treated female cafeteria diet-fed rats. A decrease in the hypothalamic leptin receptors (Ob-Ra and Ob-Rb) and pro-opiomelanocortin (POMC) mRNA was observed only in male hypertensive cafeteria diet-fed rats. Although no alterations in Ob-R occurred in both groups of female cafeteria diet-fed rats, the hyperleptinaemic state of these animals had no influence on POMC mRNA levels. In intact female rats, expression of the suppressors of cytokines signaling SOCS-1, SOCS-2, SOCS-3, and cytokine inhibitor signaling were unaltered, whereas in T-treated females SOCS-3 was overexpressed. Finally SOCS-1 mRNA level was increased only in male rats. Because hyperinsulinemia was reported to counteract the leptin-induced stimulation of the sympathetic tone and because SOCS-1 and -3 are potential inhibitors of insulin signaling, our results suggest that the hypothalamic overexpression of SOCS-1 or SOCS-3 found in male or T-treated female rats after cafeteria diet feeding could block the negative influence of the hyperinsulinemia on the central pressor action of leptin, thereby contributing to their hypertensive state.
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Affiliation(s)
- Charles Plut
- Department of Biochemistry and Molecular Biology, Faculté de Médecine de Paris-Ile de France-Ouest, Université Versailles-St Quentin en Yvelines, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France.
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Zugck C, Lossnitzer D, Backs J, Kristen A, Kinscherf R, Haass M. Increased cardiac norepinephrine release in spontaneously hypertensive rats: role of presynaptic alpha-2A adrenoceptors. J Hypertens 2003; 21:1363-9. [PMID: 12817185 DOI: 10.1097/00004872-200307000-00026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES AND DESIGN An increased sympathoadrenergic activation is thought to contribute to the maintenance of elevated blood pressure levels in hypertension. Therefore, the regulation of cardiac presynaptic sympathetic neurotransmission was investigated in spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). METHODS AND RESULTS Electrical field stimulation (1 min, 4 Hz) evoked a higher norepinephrine (NE) overflow from isolated perfused SHR than from WKY hearts (171 +/- 78 versus 111 +/- 27 nmol/g; means +/- SD, n = 7, P < 0.05). The difference in stimulation-evoked NE overflow was neither due to increased NE stores nor to a higher density of sympathetic nerve endings in SHR hearts. Furthermore, impairment of cardiac NE re-uptake was ruled out, as pharmacological inhibition of NE re-uptake by desipramine (300 nmol/l) similarly increased NE overflow from SHR (+ 54 +/- 17%) and WKY hearts (+ 59 +/- 18%). However, inhibition of presynaptic alpha-2 adrenoceptors (alpha-2R) with yohimbine (1 micromol/l) resulted in a significantly larger increase in NE overflow from WKY (+ 244 +/- 42%) than from SHR hearts (+ 162 +/- 47%, P < 0.05 versus WKY), indicating impairment of presynaptic inhibitory effect of alpha-2R in SHR. Supporting this notion, mRNA concentrations of alpha-2(A), the predominant presynaptic alpha-2R subtype, were reduced in SHR compared with WKY (738 +/- 251 versus 1468 +/- 518 mRNA molecules/10 ng, n = 7, P < 0.01), as quantified by competitive reverse transcription-polymerase chain reaction derived from left stellate ganglia. CONCLUSIONS The impairment of the alpha-2R mediated presynaptic negative feedback mechanism by a reduced expression of the alpha-2R subtype A may increase cardiac net secretion of NE in SHR and could therefore contribute to their hypertensive phenotype.
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Affiliation(s)
- Christian Zugck
- Department of Cardiology, Bergheimer Str 58, 69115 Heidelberg, Germany.
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15
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Abstract
Globally, cardiovascular disease will continue causing most human deaths for the foreseeable future. The consistent gender gap in life span of approximately 5.6 yr in all advanced economies must derive from gender differences in age-specific cardiovascular death rates, which rise steeply in parallel for both genders but 5-10 yr earlier in men. The lack of inflection point at modal age of menopause, contrasting with unequivocally estrogen-dependent biological markers like breast cancer or bone density, makes estrogen protection of premenopausal women an unlikely explanation. Limited human data suggest that testosterone exposure does not shorten life span in either gender, and oral estrogen treatment increases risk of cardiovascular death in men as it does in women. Alternatively, androgen exposure in early life (perinatal androgen imprinting) may predispose males to earlier onset of atherosclerosis. Following the recent reevaluation of the estrogen-protection orthodoxy, empirical research has flourished into the role of androgens in the progression of cardiovascular disease, highlighting the need to better understand androgen receptor (AR) coregulators, nongenomic androgen effects, tissue-specific metabolic activation of androgens, and androgen sensitivity. Novel therapeutic targets may arise from understanding how androgens enhance early plaque formation and cause vasodilatation via nongenomic androgen effects on vascular smooth muscle, and how tissue-specific variations in androgen effects are modulated by AR coregulators as well as metabolic activation of testosterone to amplify (via 5alpha-reductase to form dihydrotestosterone acting on AR) or diversify (via aromatization to estradiol acting upon estrogen receptor alpha/beta) the biological effects of testosterone on the vasculature. Observational studies show that blood testosterone concentrations are consistently lower among men with cardiovascular disease, suggesting a possible preventive role for testosterone therapy, which requires critical evaluation by further prospective studies. Short-term interventional studies show that testosterone produces a modest but consistent improvement in cardiac ischemia over placebo, comparable to the effects of existing antianginal drugs. By contrast, testosterone therapy has no beneficial effects in peripheral arterial disease but has not been evaluated in cerebrovascular disease. Erectile dysfunction is most frequently caused by pelvic arterial insufficiency due to atherosclerosis, and its sentinel relationship to generalized atherosclerosis is insufficiently appreciated. The commonality of risk factor patterns and mechanisms (including endothelial dysfunction) suggests that the efficacy of antiatherogenic therapy is an important challenge with the potential to enhance men's motivation for prevention and treatment of cardiovascular diseases.
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Affiliation(s)
- Peter Y Liu
- ANZAC Research Institute, Concord Hospital and Department of Medicine, University of Sydney, New South Wales, Australia
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Coatmellec-Taglioni G, Ribière C. Factors that influence the risk of hypertension in obese individuals. Curr Opin Nephrol Hypertens 2003; 12:305-8. [PMID: 12698070 DOI: 10.1097/00041552-200305000-00013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW Obesity, which has reached epidemic prevalence, is now recognized as an independent risk factor for increasing blood pressure. The complex mechanisms of obesity-related hypertension are unclear, but several studies have provided evidence of a hypertensive shift in pressure natriuresis. Excess sympathetic outflow to the kidneys and changes in renal structure and function may both affect the renal pressure relationship. Other factors that may contribute to altered natriuresis include hyperinsulinemia, hyperleptinemia and activation of the renin-angiotensin system. Disruption of the renal alpha2 adrenoceptors or leptin receptor implicated in natriuresis control may also be an additive risk for the increase in tubular reabsorption in obesity hypertension. RECENT FINDINGS Recent advances have highlighted the importance of two adipocyte-derived hormones - leptin and angiotensinogen - in obesity hypertension. Leptin has direct central effects that increase sympathetic outflow to the kidney and the new concept of selective leptin resistance, suggests the maintenance of leptin-induced sympathetic activation in obesity, despite resistance to leptin metabolic effects. On the other hand, a recent study showed that angiotensinogen produced in the adipocyte is also relevant to blood pressure control. SUMMARY The article reviews the factors implicated in the disruption of blood pressure control in obesity. Further investigation on the time course of the disease would reveal the relative importance of each of the factors that influence the risk of hypertension in obese individuals.
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Affiliation(s)
- Gwenn Coatmellec-Taglioni
- Department of Biochemistry and Molecular Biology, UFR Médicale Paris-lle-de-France-Ouest, Paris, France
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Coatmellec-Taglioni G, Dausse JP, Giudicelli Y, Ribière C. Sexual dimorphism in cafeteria diet-induced hypertension is associated with gender-related difference in renal leptin receptor down-regulation. J Pharmacol Exp Ther 2003; 305:362-7. [PMID: 12649390 DOI: 10.1124/jpet.102.045682] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plasma leptin levels are elevated in obesity suggesting a pathophysiologic role of this hormone in obesity and related disorders, such as hypertension. Furthermore, despite excess leptin levels, leptin satiety action is blunted in obesity suggesting the occurrence of central leptin resistance. As leptin acts on the kidney to induce natriuresis, renal leptin receptor alterations could lead to a defect in sodium excretion and hence to hypertension. Therefore, the present study investigated renal leptin receptor (Ob-Ra and Ob-Rb) mRNA and leptin binding capacities in diet-induced hypertension. Feeding male, female, and testosterone-treated female rats a cafeteria diet for 10 weeks increased body fat mass, plasma insulin, and leptin levels. Furthermore, although male and testosterone-treated female cafeteria-fed rats were hypertensive, the female rats fed the same diet failed to develop elevated blood pressure. In renal medulla, Ob-Ra and Ob-Rb mRNA levels were unchanged after cafeteria diet feeding in all groups; however, binding analysis revealed Ob-R protein down-regulation exclusively in hypertensive rats. Moreover, renal Ob-R densities were inversely correlated to plasma leptin concentrations in male rats and testosterone-treated female rats but not in female rats. These findings demonstrate the existence of differences in renal Ob-R binding capacities, which are correlated to hypertension.
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Affiliation(s)
- Gwenn Coatmellec-Taglioni
- Laboratory of Biochemistry and Molecular Biology, Faculté de Médecine de Paris-Ouest, Université René Descartes, Paris, France
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