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Mao Y, Zhao K, Li P, Sheng Y. The emerging role of leptin in obesity-associated cardiac fibrosis: evidence and mechanism. Mol Cell Biochem 2022; 478:991-1011. [PMID: 36214893 DOI: 10.1007/s11010-022-04562-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 09/15/2022] [Indexed: 11/24/2022]
Abstract
Cardiac fibrosis is a hallmark of various cardiovascular diseases, which is quite commonly found in obesity, and may contribute to the increased incidence of heart failure arrhythmias, and sudden cardiac death in obese populations. As an endogenous regulator of adiposity metabolism, body mass, and energy balance, obesity, characterized by increased circulating levels of the adipocyte-derived hormone leptin, is a critical contributor to the pathogenesis of cardiac fibrosis. Although there are some gaps in our knowledge linking leptin and cardiac fibrosis, this review will focus on the interplay between leptin and major effectors involved in the pathogenesis underlying cardiac fibrosis at both cellular and molecular levels based on the current reports. The profibrotic effect of leptin is predominantly mediated by activated cardiac fibroblasts but may also involve cardiomyocytes, endothelial cells, and immune cells. Moreover, a series of molecular signals with a known profibrotic property is closely involved in leptin-induced fibrotic events. A more comprehensive understanding of the underlying mechanisms through which leptin contributes to the pathogenesis of cardiac fibrosis may open up a new avenue for the rapid emergence of a novel therapy for preventing or even reversing obesity-associated cardiac fibrosis.
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Affiliation(s)
- Yukang Mao
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, People's Republic of China.,Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu, People's Republic of China
| | - Kun Zhao
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu, People's Republic of China
| | - Peng Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu, People's Republic of China.
| | - Yanhui Sheng
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, People's Republic of China. .,Department of Cardiology, Jiangsu Province Hospital, Nanjing, Jiangsu, People's Republic of China.
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2
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Chou CL, Lin H, Chen JS, Fang TC. Renin inhibition improves metabolic syndrome, and reduces angiotensin II levels and oxidative stress in visceral fat tissues in fructose-fed rats. PLoS One 2017; 12:e0180712. [PMID: 28700686 PMCID: PMC5507254 DOI: 10.1371/journal.pone.0180712] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 06/20/2017] [Indexed: 12/29/2022] Open
Abstract
Renin–angiotensin system in visceral fat plays a crucial role in the pathogenesis of metabolic syndrome in fructose-fed rats. However, the effects of renin inhibition on visceral adiposity in metabolic syndrome are not fully investigated. We investigated the effects of renin inhibition on visceral adiposity in fructose-fed rats. Male Wistar–Kyoto rats were divided into 4 groups for 8-week experiments: Group Con (standard chow diet), Group Fru (high-fructose diet; 60% fructose), Group FruA (high-fructose diet and concurrent aliskiren treatment; 100 mg/kg body weight [BW] per day), and Group FruB (high-fructose diet and subsequent, i.e. 4 weeks after initiating high-fructose feeding, aliskiren treatment; 100 mg/kg BW per day). The high-fructose diet induced metabolic syndrome, increased visceral fat weights and adipocyte sizes, and augmented angiotensin II (Ang II), NADPH oxidase (NOX) isoforms expressions, oxidative stress, and dysregulated production of adipocytokines from visceral adipose tissues. Concurrent and subsequent aliskiren administration ameliorated metabolic syndrome, dysregulated adipocytokines, and visceral adiposity in high fructose-fed hypertensive rats, and was associated with reducing Ang II levels, NOX isoforms expressions and oxidative stress in visceral fat tissues. Therefore, this study demonstrates renin inhibition could improve metabolic syndrome, and reduce Ang II levels and oxidative stress in visceral fat tissue in fructose-fed rats, and suggests that visceral adipose Ang II plays a crucial role in the pathogenesis of metabolic syndrome in fructose-fed rats.
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Affiliation(s)
- Chu-Lin Chou
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Heng Lin
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jin-Shuen Chen
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Te-Chao Fang
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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3
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Systemic and tissue-specific effects of aliskiren on the RAAS and carbohydrate/lipid metabolism in obese patients with hypertension. ACTA ACUST UNITED AC 2017; 11:488-497. [PMID: 28666704 DOI: 10.1016/j.jash.2017.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/04/2017] [Accepted: 06/02/2017] [Indexed: 11/20/2022]
Abstract
Aliskiren penetrates adipose and skeletal muscle in hypertensive patients with abdominal obesity and reduces renin-angiotensin-aldosterone system activity. After discontinuation, blood pressure-lowering effects are observed possibly through drug-tissue binding. We performed microdialysis evaluation of adipose tissue and skeletal muscle before and during an insulin-modified frequently sampled intravenous glucose tolerance test (IM-FSIGT). Aliskiren 300 mg (n = 8) or amlodipine 5 mg (n = 8) once daily were administered during a 12-week randomized treatment period. Aliskiren elicited variable changes in median interstitial angiotensin II (Ang II) in adipose (2.60-1.30 fmol/mL) and skeletal muscle (2.23-0.68 fmol/mL); amlodipine tended to increase adipose and skeletal muscle Ang II (P = .066 for skeletal muscle treatment difference). Glucose/insulin increased median plasma Ang II 1 hour after glucose injection (1.04-2.50 fmol/mL; P = .001), which was markedly attenuated by aliskiren but not amlodipine. Aliskiren increased glucose disposition index (P = .012) and tended to increase acute insulin response to glucose (P = .067). Fasting adipose glycerol (-17%; P = .064) and fasting muscle glucose dialysate (-17%; P = .025) were decreased by aliskiren but not amlodipine. In summary, aliskiren decreased Ang II production in response to glucose/insulin stimulus and elicited metabolic effects in adipose and skeletal muscle suggestive of increased whole-body glucose utilization.
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Caminhotto RDO, Sertié RAL, Andreotti S, Campaãa AB, Lima FB. Renin-angiotensin system blockers regulate the metabolism of isolated fat cells in vitro. ACTA ACUST UNITED AC 2017; 49:S0100-879X2016000800608. [PMID: 27487419 PMCID: PMC4974019 DOI: 10.1590/1414-431x20165409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/06/2016] [Indexed: 08/30/2023]
Abstract
Due to the presence of the renin-angiotensin system (RAS) in tissues and its specific
influence on white adipose tissue, fat cells are possible targets of pharmacological
RAS blockers commonly used as anti-hypertensive drugs. In the present study, we
investigated the effects of different RAS blockers on fat cell metabolism, more
specifically on lipolysis, lipogenesis and oxidation of energy substrates. Isolated
primary adipocytes were incubated with different RAS blockers (aliskiren, captopril
and losartan) in vitro for 24 h and lipolysis, lipogenesis and
glucose oxidation capacities were determined in dose-response assays to a
β-adrenergic agonist and to insulin. Although no change was found in lipolytic
capacity, the RAS blockers modulated lipogenesis and glucose oxidation in a different
way. While captopril decreased insulin-stimulated lipogenesis (−19% of maximal
response and −60% of insulin responsiveness) due to reduced glucose derived glycerol
synthesis (−19% of maximal response and 64% of insulin responsiveness), aliskiren
increased insulin-stimulated glucose oxidation (+49% of maximal response and +292% of
insulin responsiveness) in fat cells. Our experiments demonstrate that RAS blockers
can differentially induce metabolic alterations in adipocyte metabolism,
characterized by a reduction in lipogenic responsiveness or an increase in glucose
oxidation. The impact of RAS blockers on adipocyte metabolism may have beneficial
implications on metabolic disorders during their therapeutic use in hypertensive
patients.
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Affiliation(s)
- R de O Caminhotto
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - R A L Sertié
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - S Andreotti
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - A B Campaãa
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - F B Lima
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
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5
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Thornton SN. Increased Hydration Can Be Associated with Weight Loss. Front Nutr 2016; 3:18. [PMID: 27376070 PMCID: PMC4901052 DOI: 10.3389/fnut.2016.00018] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/30/2016] [Indexed: 12/25/2022] Open
Abstract
This mini-review develops the hypothesis that increased hydration leads to body weight loss, mainly through a decrease in feeding, and a loss of fat, through increased lipolysis. The publications cited come from animal, mainly rodent, studies where manipulations of the central and/or the peripheral renin–angiotensin system lead to an increased drinking response and a decrease in body weight. This hypothesis derives from a broader association between chronic hypohydration (extracellular dehydration) and raised levels of the hormone angiotensin II (AngII) associated with many chronic diseases, such as obesity, diabetes, cancer, and cardiovascular disease. Proposed mechanisms to explain these effects involve an increase in metabolism due to hydration expanding cell volume. The results of these animal studies often can be applied to the humans. Human studies are consistent with this hypothesis for weight loss and for reducing the risk factors in the development of obesity and type 2 diabetes.
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Affiliation(s)
- Simon N Thornton
- INSERM U_1116, Université de Lorraine , Vandoeuvre les Nancy , France
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6
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Lu H, Cassis LA, Kooi CWV, Daugherty A. Structure and functions of angiotensinogen. Hypertens Res 2016; 39:492-500. [PMID: 26888118 PMCID: PMC4935807 DOI: 10.1038/hr.2016.17] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 12/13/2022]
Abstract
Angiotensinogen (AGT) is the sole precursor of all angiotensin peptides. Although AGT is generally considered as a passive substrate of the renin-angiotensin system, there is accumulating evidence that the regulation and functions of AGT are intricate. Understanding the diversity of AGT properties has been enhanced by protein structural analysis and animal studies. In addition to whole-body genetic deletion, AGT can be regulated in vivo by cell-specific procedures, adeno-associated viral approaches and antisense oligonucleotides. Indeed, the availability of these multiple manipulations of AGT in vivo has provided new insights into the multifaceted roles of AGT. In this review, the combination of structural and functional studies is highlighted to focus on the increasing recognition that AGT exerts effects beyond being a sole provider of angiotensin peptides.
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Affiliation(s)
- Hong Lu
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Lisa A Cassis
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Craig W Vander Kooi
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA.,Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
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7
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Claflin KE, Grobe JL. Control of energy balance by the brain renin-angiotensin system. Curr Hypertens Rep 2016; 17:38. [PMID: 25833461 DOI: 10.1007/s11906-015-0549-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The renin-angiotensin system (RAS) exists as a circulating hormone system but it is also used by various tissues of the body, including the brain, as a paracrine signaling mechanism. The local brain version of the RAS is mechanistically involved in fluid balance and blood pressure control, and there is growing appreciation for a role of the brain RAS in the control of energy balance. Here, we review major evidence for the control of energy balance by the brain RAS; outline the current understanding of the RAS components, targets, and mechanisms involved; and highlight some major questions that currently face the field.
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Affiliation(s)
- Kristin E Claflin
- Department of Pharmacology, Center for Hypertension Research, Obesity Research & Education Initiative, François M. Abboud Cardiovascular Research Center, and Fraternal Order of Eagles' Diabetes Research Center, University of Iowa, 51 Newton Rd., 2-307 BSB, Iowa City, IA, 52242, USA
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Lee KC, Hsieh YC, Yang YY, Chan CC, Huang YH, Lin HC. Aliskiren Reduces Hepatic steatosis and Epididymal Fat Mass and Increases Skeletal Muscle Insulin Sensitivity in High-Fat Diet-Fed Mice. Sci Rep 2016; 6:18899. [PMID: 26732252 PMCID: PMC4702081 DOI: 10.1038/srep18899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 10/15/2015] [Indexed: 02/06/2023] Open
Abstract
Aliskiren has been found to reduce chronic injury and steatosis in the liver of methionine-choline-deficient (MCD) diet-fed mice. This study investigated whether aliskiren has an anti-steatotic effect in HFD-fed mice, which are more relevant to human patients with non-alcoholic fatty liver disease than MCD mice. Mice fed with 4-week normal chow or HFD randomly received aliskiren (50 mg/kg/day) or vehicle via osmotic minipumps for further 4 weeks. Aliskiren reduced systemic insulin resistance, hepatic steatosis, epididymal fat mass and increased gastrocnemius muscle glucose transporter type 4 levels with lower tissue angiotensin II levels in the HFD-fed mice. In addition, aliskiren lowered nuclear peroxisome proliferator-activated receptor gamma and its down-signaling molecules and increased cytochrome P450 4A14 and carnitine palmitoyltransferase 1A (CPT1a) in liver. In epididymal fat, aliskiren inhibited expressions of lipogenic genes, leading to decrease in fat mass, body weight, and serum levels of leptin and free fatty acid. Notably, in the gastrocnemius muscle, aliskiren increased phosphorylation of insulin receptor substrate 1 and Akt. Based on these beneficial effects on liver, peripheral fat and skeletal muscle, aliskiren is a promising therapeutic agent for patients with NAFLD.
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Affiliation(s)
- Kuei-Chuan Lee
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Yun-Cheng Hsieh
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Ying-Ying Yang
- Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Division of General Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Division of Clinical Skill Training, Department of Medical Education, Taipei Veterans General Hospital
| | - Che-Chang Chan
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Yi-Hsiang Huang
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Han-Chieh Lin
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
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9
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Chen W, Leo S, Weng C, Yang X, Wu Y, Tang X. Mechanisms mediating renal sympathetic nerve activation in obesity-related hypertension. Herz 2015; 40 Suppl 2:190-6. [PMID: 24609799 DOI: 10.1007/s00059-014-4072-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Excessive renal sympathetic nerve activation may be one of the mechanisms underlying obesity-related hypertension. Impaired baroreflex sensitivity, adipokine disorders-such as leptin, adiponectin, and resistin-activation of the renin-angiotensin system, hyperinsulinemia, insulin resistance, and renal sodium retention present in obesity increase renal sympathetic nerve activity, thus contributing to the development of hypertension. Renal sympathetic denervation reduces both renal sympathetic activity and blood pressure in patients with obesity-related hypertension.
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Affiliation(s)
- W Chen
- Department of Cardiology, The Third Xiangya Hospital, Central South University, 410013, Changsha, China
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10
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Lu H, Wu C, Howatt DA, Balakrishnan A, Moorleghen JJ, Chen X, Zhao M, Graham MJ, Mullick AE, Crooke RM, Feldman DL, Cassis LA, Vander Kooi CW, Daugherty A. Angiotensinogen Exerts Effects Independent of Angiotensin II. Arterioscler Thromb Vasc Biol 2015; 36:256-65. [PMID: 26681751 DOI: 10.1161/atvbaha.115.306740] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/03/2015] [Indexed: 01/16/2023]
Abstract
OBJECTIVE This study determined whether angiotensinogen (AGT) has angiotensin II-independent effects using multiple genetic and pharmacological manipulations. APPROACH AND RESULTS All study mice were in low-density lipoprotein receptor -/- background and fed a saturated fat-enriched diet. In mice with floxed alleles and a neomycin cassette in intron 2 of the AGT gene (hypoAGT mice), plasma AGT concentrations were >90% lower compared with their wild-type littermates. HypoAGT mice had lower systolic blood pressure, less atherosclerosis, and diminished body weight gain and liver steatosis. Low plasma AGT concentrations and all phenotypes were recapitulated in mice with hepatocyte-specific deficiency of AGT or pharmacological inhibition of AGT by antisense oligonucleotide administration. In contrast, inhibition of AGT cleavage by a renin inhibitor, aliskiren, failed to alter body weight gain and liver steatosis in low-density lipoprotein receptor -/- mice. In mice with established adiposity, administration of AGT antisense oligonucleotide versus aliskiren led to equivalent reductions of systolic blood pressure and atherosclerosis. AGT antisense oligonucleotide administration ceased body weight gain and further reduced body weight, whereas aliskiren did not affect body weight gain during continuous saturated fat-enriched diet feeding. Structural comparisons of AGT proteins in zebrafish, mouse, rat, and human revealed 4 highly conserved sequences within the des(angiotensin I)AGT domain. des(angiotensin I)AGT, through adeno-associated viral infection in hepatocyte-specific AGT-deficient mice, increased body weight gain and liver steatosis, but did not affect atherosclerosis. CONCLUSIONS AGT contributes to body weight gain and liver steatosis through functions of the des(angiotensin I)AGT domain, which are independent of angiotensin II production.
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Affiliation(s)
- Hong Lu
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Congqing Wu
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Deborah A Howatt
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Anju Balakrishnan
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Jessica J Moorleghen
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Xiaofeng Chen
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Mingming Zhao
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Mark J Graham
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Adam E Mullick
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Rosanne M Crooke
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - David L Feldman
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Lisa A Cassis
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Craig W Vander Kooi
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.)
| | - Alan Daugherty
- From the Saha Cardiovascular Research Center (H.L., C.W., D.A.H., A.B., J.J.M., X.C., M.Z., A.D.); Departments of Physiology (H.L., A.D.), Pharmacology and Nutritional Sciences (C.W., L.A.C., A.D.), and Molecular and Cellular Biochemistry (C.W.V.K.), University of Kentucky, Lexington; Isis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G., A.E.M., R.M.C.); and Novartis Pharmaceuticals Corporation, East Hanover, NJ (D.L.F.).
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11
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Abstract
Hypertension is one of the most common causes of death across the globe. Many trials and drugs have been used for controlling the debilitating effects of hypertension. One such new class of drug is direct renin inhibitors (DRI), e.g., aliskiren, which block the renin-angiotensin system (RAS). It blocks the very first step in the RAS system. Multiple trials have been carried out debating the outcome of monotherapy and combination therapy with other classes of hypertensive drugs. Focus on compliance, adverse effects, and the cost have also been in the news. Extensive studies are still needed to justify the clinical use of a DRI in the effective treatment of hypertension.
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Affiliation(s)
- Adnan Bashir Bhatti
- Department of Medicine, Capital Development Authority Hospital, Islamabad, Pakistan
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12
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Littlejohn NK, Grobe JL. Opposing tissue-specific roles of angiotensin in the pathogenesis of obesity, and implications for obesity-related hypertension. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1463-73. [PMID: 26491099 DOI: 10.1152/ajpregu.00224.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 10/15/2015] [Indexed: 12/24/2022]
Abstract
Metabolic disease, specifically obesity, has now become the greatest challenge to improving cardiovascular health. The renin-angiotensin system (RAS) exists as both a circulating hormone system and as a local paracrine signaling mechanism within various tissues including the brain, kidney, and adipose, and this system is strongly implicated in cardiovascular health and disease. Growing evidence also implicates the RAS in the control of energy balance, supporting the concept that the RAS may be mechanistically involved in the pathogenesis of obesity and obesity hypertension. Here, we review the involvement of the RAS in the entire spectrum of whole organism energy balance mechanisms, including behaviors (food ingestion and spontaneous physical activity) and biological processes (digestive efficiency and both aerobic and nonaerobic resting metabolic rates). We hypothesize that opposing, tissue-specific effects of the RAS to modulate these various components of energy balance can explain the apparently paradoxical results reported by energy-balance studies that involve stimulating, versus disrupting, the RAS. We propose a model in which such opposing and tissue-specific effects of the RAS can explain the failure of simple, global RAS blockade to result in weight loss in humans, and hypothesize that obesity-mediated uncoupling of endogenous metabolic rate control mechanisms can explain the phenomenon of obesity-related hypertension.
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Affiliation(s)
- Nicole K Littlejohn
- Department of Pharmacology, the Obesity Research and Education Initiative, the Fraternal Order of Eagles' Diabetes Research Center, the François M. Abboud Cardiovascular Research Center, and the Center for Hypertension Research, University of Iowa, Iowa City, Iowa
| | - Justin L Grobe
- Department of Pharmacology, the Obesity Research and Education Initiative, the Fraternal Order of Eagles' Diabetes Research Center, the François M. Abboud Cardiovascular Research Center, and the Center for Hypertension Research, University of Iowa, Iowa City, Iowa
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13
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Tang SQ, Yin S, Liu S, Le KJ, Yang RL, Liu JH, Wang XL, Zheng ZX, Zheng L, Lin Q, Lu Y. N-stearoyltyrosine dipotassium ameliorates high-fat diet-induced obesity in C57BL/6 mice. Eur J Pharm Sci 2015; 74:18-26. [DOI: 10.1016/j.ejps.2015.03.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 03/14/2015] [Accepted: 03/29/2015] [Indexed: 01/13/2023]
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14
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Weidemann BJ, Voong S, Morales-Santiago FI, Kahn MZ, Ni J, Littlejohn NK, Claflin KE, Burnett CML, Pearson NA, Lutter ML, Grobe JL. Dietary Sodium Suppresses Digestive Efficiency via the Renin-Angiotensin System. Sci Rep 2015; 5:11123. [PMID: 26068176 PMCID: PMC4464075 DOI: 10.1038/srep11123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/18/2015] [Indexed: 12/22/2022] Open
Abstract
Dietary fats and sodium are both palatable and are hypothesized to synergistically contribute to ingestive behavior and thereby obesity. Contrary to this hypothesis, C57BL/6J mice fed a 45% high fat diet exhibited weight gain that was inhibited by increased dietary sodium content. This suppressive effect of dietary sodium upon weight gain was mediated specifically through a reduction in digestive efficiency, with no effects on food intake behavior, physical activity, or resting metabolism. Replacement of circulating angiotensin II levels reversed the effects of high dietary sodium to suppress digestive efficiency. While the AT1 receptor antagonist losartan had no effect in mice fed low sodium, the AT2 receptor antagonist PD-123,319 suppressed digestive efficiency. Correspondingly, genetic deletion of the AT2 receptor in FVB/NCrl mice resulted in suppressed digestive efficiency even on a standard chow diet. Together these data underscore the importance of digestive efficiency in the pathogenesis of obesity, and implicate dietary sodium, the renin-angiotensin system, and the AT2 receptor in the control of digestive efficiency regardless of mouse strain or macronutrient composition of the diet. These findings highlight the need for greater understanding of nutrient absorption control physiology, and prompt more uniform assessment of digestive efficiency in animal studies of energy balance.
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Affiliation(s)
| | - Susan Voong
- Departments of Pharmacology, University of Iowa, Iowa City, IA
| | | | - Michael Z Kahn
- Departments of Psychiatry, University of Iowa, Iowa City, IA
| | - Jonathan Ni
- Departments of Pharmacology, University of Iowa, Iowa City, IA
| | | | | | | | | | - Michael L Lutter
- 1] Departments of Psychiatry, University of Iowa, Iowa City, IA. [2] The Fraternal Order of Eagles' Diabetes Research Center, University of Iowa, Iowa City, IA. [3] The Obesity Research and Education Initiative, University of Iowa, Iowa City, IA
| | - Justin L Grobe
- 1] Departments of Pharmacology, University of Iowa, Iowa City, IA. [2] The Fraternal Order of Eagles' Diabetes Research Center, University of Iowa, Iowa City, IA. [3] The Obesity Research and Education Initiative, University of Iowa, Iowa City, IA. [4] The Center for Hypertension Research, University of Iowa, Iowa City, IA
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Comparative effects of Aliskiren and Telmisartan in high fructose diet-induced metabolic syndrome in rats. Eur J Pharmacol 2015; 760:145-53. [PMID: 25917321 DOI: 10.1016/j.ejphar.2015.04.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/06/2015] [Accepted: 04/15/2015] [Indexed: 01/18/2023]
Abstract
Fructose is a commonly used sweetener associated with diets that increase the prevalence of metabolic syndrome (MS). Inhibition of the renin-angiotensin system (RAS) has been consistently demonstrated to reduce MS. However, there has been no direct comparison among different pharmacological modes of inhibiting the RAS concerning their effects on MS. This study investigated the effect of aliskiren, a direct renin inhibitor, versus telmisartan, an angiotensin II-receptor blocker, in the treatment of fructose-induced MS in rats. MS was induced by high fructose (FRC) diet feeding for 12 weeks. Oral administrations of telmisartan (TEL, 5 mg/kg), aliskiren (ALS, 30 mg/kg) or vehicle were started in the last 4 weeks. Results showed that administration of either TEL or ALS with FRC diet equally ameliorated the metabolic parameters (glucose level, oral glucose tolerance test, insulin resistance and serum lipids profile), systolic blood pressure and oxidative stress markers (malondialdehyde, nitric oxide, reduced glutathione levels and catalase activity). Additionally, the effects of TEL and ALS were associated with a decrease in body composition index and attenuation of liver index, serum liver enzyme activities and hepatic expressions of inflammatory and fibrotic markers (tumor necrosis factor-α, nuclear factor kappa-B and transforming growth factor-β) with a significant increase in hepatic glucose transporter-2 and peroxisome proliferator-activated receptors-alpha and gamma expressions. The results suggested that, at indicated dosage, ALS has ameliorative effect equal to that of TEL against FRC-induced metabolic and hepatic disorders; implying that drugs which inhibit the RAS, by different mode of inhibition, profoundly affect fructose-induced MS in rats.
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Chou CL, Pang CY, Lee TJF, Fang TC. Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats. PLoS One 2015; 10:e0119843. [PMID: 25774877 PMCID: PMC4361671 DOI: 10.1371/journal.pone.0119843] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 02/03/2015] [Indexed: 01/23/2023] Open
Abstract
Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group). Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose) for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L). These results suggest a protective role of calcitriol treatment on endothelial function, glucose tolerance, and visceral adiposity in fructose-fed rats.
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Affiliation(s)
- Chu-Lin Chou
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Cheng-Yoong Pang
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Tony J. F. Lee
- Institutes of Life Sciences, Pharmacology & Toxicology, and Medical Sciences, Tzu Chi University, Hualien, Taiwan
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Te-Chao Fang
- Division of Nephrology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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17
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Favre GA, Esnault VLM, Van Obberghen E. Modulation of glucose metabolism by the renin-angiotensin-aldosterone system. Am J Physiol Endocrinol Metab 2015; 308:E435-49. [PMID: 25564475 DOI: 10.1152/ajpendo.00391.2014] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The renin-angiotensin-aldosterone system (RAAS) is an enzymatic cascade functioning in a paracrine and autocrine fashion. In animals and humans, RAAS intrinsic to tissues modulates food intake, metabolic rate, adiposity, insulin sensitivity, and insulin secretion. A large array of observations shows that dysregulation of RAAS in the metabolic syndrome favors type 2 diabetes. Remarkably, angiotensin-converting enzyme inhibitors, suppressing the synthesis of angiotensin II (ANG II), and angiotensin receptor blockers, targeting the ANG II type 1 receptor, prevent diabetes in patients with hypertensive or ischemic cardiopathy. These drugs interrupt the negative feedback loop of ANG II on the RAAS cascade, which results in increased production of angiotensins. In addition, they change the tissue expression of RAAS components. Therefore, the concept of a dual axis of RAAS regarding glucose homeostasis has emerged. The RAAS deleterious axis increases the production of inflammatory cytokines and raises oxidative stress, exacerbating the insulin resistance and decreasing insulin secretion. The beneficial axis promotes adipogenesis, blocks the production of inflammatory cytokines, and lowers oxidative stress, thereby improving insulin sensitivity and secretion. Currently, drugs targeting RAAS are not given for the purpose of preventing diabetes in humans. However, we anticipate that in the near future the discovery of novel means to modulate the RAAS beneficial axis will result in a decisive therapeutic breakthrough.
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Affiliation(s)
- Guillaume A Favre
- Institut National de la Sante et de la Recherche Medicale, U 1081, Institute for Research on Cancer and Aging of Nice (IRCAN), "Aging and Diabetes" Team, Nice, France; Centre National de la Recherche Scientifique, UMR7284, IRCAN, Nice, France; University of Nice-Sophia Antipolis, Nice, France; Nephrology Department, University Hospital, Nice, France; and
| | - Vincent L M Esnault
- Institut National de la Sante et de la Recherche Medicale, U 1081, Institute for Research on Cancer and Aging of Nice (IRCAN), "Aging and Diabetes" Team, Nice, France; Centre National de la Recherche Scientifique, UMR7284, IRCAN, Nice, France; University of Nice-Sophia Antipolis, Nice, France; Nephrology Department, University Hospital, Nice, France; and
| | - Emmanuel Van Obberghen
- Institut National de la Sante et de la Recherche Medicale, U 1081, Institute for Research on Cancer and Aging of Nice (IRCAN), "Aging and Diabetes" Team, Nice, France; Centre National de la Recherche Scientifique, UMR7284, IRCAN, Nice, France; University of Nice-Sophia Antipolis, Nice, France; Clinical Chemistry Laboratory, University Hospital, Nice, France
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18
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Zaporowska-Stachowiak I, Hoffmann K, Bryl W, Minczykowski A. Aliskiren - an alternative to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in the therapy of arterial hypertension. Arch Med Sci 2014; 10:830-6. [PMID: 25276171 PMCID: PMC4175758 DOI: 10.5114/aoms.2013.34723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/23/2012] [Accepted: 12/20/2012] [Indexed: 12/11/2022] Open
Abstract
There has been enormous progress in antihypertensive therapy over the last few decades. However, the management of arterial hypertension is still insufficient and more efforts are needed to improve both non-pharmacological and pharmacological treatment of this widely prevalent disease. Renin-angiotensin-aldosterone system (RAAS) inhibition is crucial both for blood pressure (BP) control and for prevention of organ damage or its development in patients with hypertension. Angiotensin-converting enzyme inhibitors and/or sartans block RAAS incompletely. Aliskiren is one of the novel drugs that has been introduced to antihypertensive therapy recently. Up to now no trial has confirmed that aliskiren is efficacious in reducing cardiovascular events. Double RAAS blockade with aliskiren was not always safe. This review article presents the current view on the place of aliskiren in the therapy of arterial hypertension.
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Affiliation(s)
| | - Karolina Hoffmann
- Chair and Department of Internal Medicine, Metabolic Disorders and Arterial Hypertension, Poznan University of Medical Sciences, Poland
| | - Wiesław Bryl
- Chair and Department of Internal Medicine, Metabolic Disorders and Arterial Hypertension, Poznan University of Medical Sciences, Poland
| | - Andrzej Minczykowski
- Department of Cardiology-Intensive Therapy, Poznan University of Medical Sciences, Poland
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Smith PM, Hindmarch CCT, Murphy D, Ferguson AV. AT1 receptor blockade alters nutritional and biometric development in obesity-resistant and obesity-prone rats submitted to a high fat diet. Front Psychol 2014; 5:832. [PMID: 25120524 PMCID: PMC4114257 DOI: 10.3389/fpsyg.2014.00832] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/12/2014] [Indexed: 12/16/2022] Open
Abstract
Obesity is a chronic metabolic condition with important public health implications associated with numerous co-morbidities including cardiovascular disease, insulin resistance, and hypertension. The renin angiotensin system (RAS), best known for its involvement in cardiovascular control and body fluid homeostasis has, more recently, been implicated in regulation of energy balance. Interference with the RAS (genetically or pharmacologically) has been shown to influence body weight gain. In this study we investigated the effects of systemic AT1 receptor blockade using losartan on ingestive behaviors and weight gain in diet induced obese (DIO) rats. Prior to losartan administration (30 mg/kg/day) body weight gain remained constant within the DIO animals (3.6 ± 0.3 g/day, n = 8), diet resistant (DR) animals (2.1 ± 0.6 g/day, n = 8) and in the age-matched chow fed control (CHOW) animals (2.8 ± 0.3 g/day, n = 8), Losartan administration abolished body weight gain in animals fed a high fat diet (DIO: -0.4 ± 0.7 g/day, n = 8; and DR: -0.8 ± 0.3 g/day, n = 8) while chow fed animals continued to gain weight (2.2 ± 0.3 g/day, n = 8) as they had previously to oral administration of losartan. This decrease in daily body weight gain was accompanied by a decrease in food intake in the HFD fed animals. Following the removal of losartan, both the DIO and DR animals again showed daily increases in body weight gain and food intake which were similar to control values. Our data demonstrate that oral losartan administration attenuates body weight gain in animals fed a HFD whether the animal is obese (DIO) or not DR while having no effect on body weight gain in age-matched chow fed animals suggesting a protective effect of losartan against body weight gain while on a HFD.
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Affiliation(s)
- Pauline M Smith
- Department of Biomedical and Molecular Sciences, Queen's University Kingston, ON, Canada
| | - Charles C T Hindmarch
- The Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol Bristol, UK ; Department of Physiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - David Murphy
- The Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol Bristol, UK ; Department of Physiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Alastair V Ferguson
- Department of Biomedical and Molecular Sciences, Queen's University Kingston, ON, Canada
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20
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The renin-angiotensin system in adipose tissue and its metabolic consequences during obesity. J Nutr Biochem 2013; 24:2003-15. [PMID: 24120291 DOI: 10.1016/j.jnutbio.2013.07.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 05/24/2013] [Accepted: 07/22/2013] [Indexed: 02/07/2023]
Abstract
Obesity is a worldwide disease that is accompanied by several metabolic abnormalities such as hypertension, hyperglycemia and dyslipidemia. The accelerated adipose tissue growth and fat cell hypertrophy during the onset of obesity precedes adipocyte dysfunction. One of the features of adipocyte dysfunction is dysregulated adipokine secretion, which leads to an imbalance of pro-inflammatory, pro-atherogenic versus anti-inflammatory, insulin-sensitizing adipokines. The production of renin-angiotensin system (RAS) components by adipocytes is exacerbated during obesity, contributing to the systemic RAS and its consequences. Increased adipose tissue RAS has been described in various models of diet-induced obesity (DIO) including fructose and high-fat feeding. Up-regulation of the adipose RAS by DIO promotes inflammation, lipogenesis and reactive oxygen species generation and impairs insulin signaling, all of which worsen the adipose environment. Consequently, the increase of circulating RAS, for which adipose tissue is partially responsible, represents a link between hypertension, insulin resistance in diabetes and inflammation during obesity. However, other nutrients and food components such as soy protein attenuate adipose RAS, decrease adiposity, and improve adipocyte functionality. Here, we review the molecular mechanisms by which adipose RAS modulates systemic RAS and how it is enhanced in obesity, which will explain the simultaneous development of metabolic syndrome alterations. Finally, dietary interventions that prevent obesity and adipocyte dysfunction will maintain normal RAS concentrations and effects, thus preventing metabolic diseases that are associated with RAS enhancement.
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Marcus Y, Shefer G, Stern N. Adipose tissue renin-angiotensin-aldosterone system (RAAS) and progression of insulin resistance. Mol Cell Endocrinol 2013; 378:1-14. [PMID: 22750719 DOI: 10.1016/j.mce.2012.06.021] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 06/24/2012] [Indexed: 12/31/2022]
Abstract
This review focuses on the expression of the key components of the renin-angiotensin-aldosterone axis in fat tissue. At the center of this report is the role of RAAS in normal and excessive fat mass enlargement, the leading etiology of insulin resistance. Understanding the expression and regulation of RAAS components in various fat depots allows insight not only into the processes by which these complex patterns are modified by the enlargement of adipose tissue, but also into their impact on local and systemic response to insulin.
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Affiliation(s)
- Yonit Marcus
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel Aviv 64239, Israel
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Potential of RAS inhibition to improve metabolic bone disorders. BIOMED RESEARCH INTERNATIONAL 2013; 2013:932691. [PMID: 23971050 PMCID: PMC3736485 DOI: 10.1155/2013/932691] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/02/2013] [Indexed: 02/07/2023]
Abstract
Metabolic bone disorder is usually caused by abnormalities of minerals and hormones metabolism. Recently, it has been proved by several studies that the renin-angiotensin system (RAS) in local bone tissue is directly involved in bone metabolism. Activation of skeletal RAS plays an important role in bone metabolic disorders. Based on in vitro, in vivo, and clinical studies, this review explains the roles of RAS in bone metabolism and also covers the potential approaches and beneficial effects of RAS inhibition on bone health. Differential strategies for inhibiting RAS can be employed to maintain bone health, which are attributed primarily to the reduced level of angiotensin II (AngII) and suppressed stimulation of the AngII signaling pathway. The use of renin inhibitors, angiotensin-converting enzyme inhibitors, and AngII receptor blockers either individually or in combination with each other could have promising results in fighting bone metabolic disorders associated with other cardiovascular diseases as well as independent bone injuries.
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Maser RE, Lenhard MJ, Kolm P, Edwards DG. Direct renin inhibition improves parasympathetic function in diabetes. Diabetes Obes Metab 2013; 15:28-34. [PMID: 22834767 PMCID: PMC3524360 DOI: 10.1111/j.1463-1326.2012.01669.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/18/2012] [Accepted: 07/23/2012] [Indexed: 11/30/2022]
Abstract
AIM The renin-angiotensin-aldosterone system (RAAS) and autonomic nervous system regulate the cardiovascular system. Blockade of the RAAS may slow the progression of end-organ damage. Direct renin inhibition offers a means for blocking the RAAS. The objective of this study was to examine the effect of direct renin inhibition on cardiovascular autonomic function. METHODS In this double-blind, placebo-controlled trial, 60 individuals with diabetes were randomly assigned to 300 mg of aliskiren or placebo once daily for 6 weeks. The primary end point was a change in tests of cardiovascular autonomic function. Autonomic function was assessed by power spectral analysis and RR-variation during deep breathing [i.e. mean circular resultant (MCR), expiration/inspiration (E/I) ratio]. The MCR and E/I ratio assess parasympathetic function. Secondary measures included change in biochemical parameters [e.g. plasma renin activity, leptin and interleukin-6]. Change in cardiovascular autonomic function and blood analytes were analysed by a mixed effects model for repeated measures. RESULTS Baseline characteristics were similar between treatment groups. In response to aliskiren compared with placebo, blood pressure was reduced as well as plasma renin activity [from 2.4 ± 3.8 (mean ± standard deviation) to 0.5 ± 0.4 µg/l/h, p < 0.001]. There was a significant interaction (aliskiren × visit) for MCR (p = 0.003) and E/I ratio (p = 0.003) indicating improvement in MCR and E/I ratio for those on aliskiren. MCR means, baseline vs. follow-up, were 41.8 ± 19.7 vs. 50.8 ± 26.1 (aliskiren) and 38.2 ± 23.6 vs. 37.5 ± 24.1 (placebo). CONCLUSIONS Parasympathetic function (i.e. MCR and E/I ratio) was enhanced by downregulation of the RAAS.
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Affiliation(s)
- R E Maser
- Department of Medical Laboratory Sciences, University of Delaware, Newark, DE 19716, USA.
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24
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Abstract
Aging is associated with an imbalance in sympathetic and parasympathetic outflow to cardiovascular effector organs. This autonomic imbalance contributes to the decline in cardiovagal baroreceptor reflex function during aging, which allows for unrestrained activation of the sympathetic nervous system to negatively impact resting systolic blood pressure and its variability. Further, impaired baroreflex function can contribute to the development of insulin resistance and other features of the metabolic syndrome during aging through overlap in autonomic neural pathways that regulate both cardiovascular and metabolic functions. Increasing evidence supports a widespread influence of the renin-angiotensin system (RAS) on both sympathetic and parasympathetic activity through receptors distributed to peripheral and central sites of action. Indeed, therapeutic interventions to block the RAS are well established for the treatment of hypertension in elderly patients, and reduce the incidence of new-onset diabetes in clinical trials. Further, RAS blockade increases lifespan and improves numerous age-related pathologies in rodents, often independent of blood pressure. The beneficial effects of these interventions are at least in part attributed to suppression of angiotensin II formed locally within the brain. In particular, recent insights from transgenic rodents provide evidence that long-term alteration in the brain RAS modulates the balance between angiotensin II and angiotensin-(1-7), and related intracellular signaling pathways, to influence cardiovascular and metabolic function in the context of hypertension and aging.
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Hilzendeger AM, Morgan DA, Brooks L, Dellsperger D, Liu X, Grobe JL, Rahmouni K, Sigmund CD, Mark AL. A brain leptin-renin angiotensin system interaction in the regulation of sympathetic nerve activity. Am J Physiol Heart Circ Physiol 2012; 303:H197-206. [PMID: 22610169 DOI: 10.1152/ajpheart.00974.2011] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The sympathetic nervous system, leptin, and renin-angiotensin system (RAS) have been implicated in obesity-associated hypertension. There is increasing evidence for the presence of both leptin and angiotensin II receptors in several key brain cardiovascular and metabolic control regions. We tested the hypothesis that the brain RAS plays a facilitatory role in the sympathetic nerve responses to leptin. In rats, intracerebroventricular (ICV) administration of losartan (5 μg) selectively inhibited increases in renal and brown adipose tissue (BAT) sympathetic nerve activity (SNA) produced by leptin (10 μg ICV) but did not reduce the SNA responses to corticotrophin-releasing factor (CRF) or the melanocortin receptor agonist MTII. In mice with deletion of angiotensin II type-1a receptors (AT(1a)R(-/-)), increases in renal and BAT SNA induced by leptin (2 μg ICV) were impaired whereas SNA responses to MTII were preserved. Decreases in food intake and body weight with ICV leptin did not differ in AT(1a)R(-/-) vs. AT(1a)R(+/+) mice. ICV leptin in rats increased AT(1a)R and angiotensin-converting enzyme (ACE) mRNA in the subfornical organ and AT(1a)R mRNA in the arcuate nucleus, suggesting leptin-induced upregulation of the brain RAS in specific brain regions. To evaluate the role of de novo production of brain angiotensin II in SNA responses to leptin, we treated rats with captopril (12.5 μg ICV). Captopril attenuated leptin effects on renal and BAT SNA. In conclusion, these studies provide evidence that the brain RAS selectively facilitates renal and BAT sympathetic nerve responses to leptin while sparing effects on food intake.
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Affiliation(s)
- Aline M Hilzendeger
- Center on Functional Genomics of Hypertension, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Gandhi S, Srinivasan B, Akarte AS. Effective blockade of RAAS by combination of aliskiren and olmesartan improves glucose homeostasis, glomerular filtration rate along with renal variables in streptozotocin induced diabetic rats. Eur J Pharm Sci 2012; 46:32-42. [DOI: 10.1016/j.ejps.2012.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/18/2012] [Accepted: 02/06/2012] [Indexed: 11/26/2022]
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Grobe JL, Rahmouni K, Liu X, Sigmund CD. Metabolic rate regulation by the renin-angiotensin system: brain vs. body. Pflugers Arch 2012; 465:167-75. [PMID: 22491893 DOI: 10.1007/s00424-012-1096-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/02/2012] [Indexed: 01/28/2023]
Abstract
Substantial evidence supports a role for the renin-angiotensin system (RAS) in the regulation of metabolic function, but an apparent paradox exists where genetic or pharmacological inhibition of the RAS occasionally has similar physiological effects as chronic angiotensin infusion. Similarly, while RAS targeting in animal models has robust metabolic consequences, effects in humans are more subtle. Here, we review the data supporting a role for the RAS in metabolic rate regulation and propose a model where the local brain RAS works in opposition to the peripheral RAS, thus helping to explain the paradoxically similar effects of RAS supplementation and inhibition. Selectively modulating the peripheral RAS or brain RAS may thus provide a more effective treatment paradigm for obesity and obesity-related disorders.
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Affiliation(s)
- Justin L Grobe
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 3181 MERF, 375 Newton Rd., Iowa City, IA 52242, USA
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Kwak CS, Park SC, Song KY. Doenjang, a fermented soybean paste, decreased visceral fat accumulation and adipocyte size in rats fed with high fat diet more effectively than nonfermented soybeans. J Med Food 2012; 15:1-9. [PMID: 22082067 DOI: 10.1089/jmf.2010.1224] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Soybean is known to have an anti-obesity effect. We compared the anti-obesity effect of doenjang, a fermented soybean paste, with that of nonfermented soybeans in rats. Steamed soybeans and doenjang (steamed soybeans fermented and aged for 10 months) were sampled and freeze-dried. Male Sprague-Dawley rats were fed basal (BA) (5% fat), high fat (HF) (30% fat), HF+steamed soybeans (SOY), or HF+doenjang (DJ) diet ad libitum for 8 weeks. HF significantly increased body weight gain, liver weight, hepatic triglyceride (TG) and cholesterol levels, and epididymal fat pad weight compared with BA. Compared with HF, body weight gain and hepatic TG and cholesterol levels were significantly lower in SOY and DJ groups, but they were not significantly different from each other. DJ significantly reduced visceral fat weight and epididymal adipocyte size compared with HF, whereas SOY resulted in a mild reduction without significance. This was possibly because DJ showed lowered fatty acid synthase (FAS) activity and elevated carnitine palmitoyltransferase (CPT)-1 activity in liver tissue more than SOY. SOY and DJ did not affect serum total and high-density lipoprotein-cholesterol levels compared with HF; however, DJ significantly lowered the atherogenic index and serum leptin level. In conclusion, doenjang, a fermented soybean product, was more effective than soybeans for preventing diet-induced visceral fat accumulation, possibly because of its greater effects on CPT-1 activity stimulation and FAS activity suppression. These effects may be due in part to the higher content of aglycone isoflavones in doenjang.
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Affiliation(s)
- Chung Shil Kwak
- Institute on Aging, Seoul National University, Seoul, Korea.
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Achard V, Tassistro V, Boullu-Ciocca S, Grino M. Expression and nutritional regulation of the (pro)renin receptor in rat visceral adipose tissue. J Endocrinol Invest 2011; 34:840-6. [PMID: 21483231 DOI: 10.3275/7627] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Early life nutritional environment plays an important role in the development of visceral adipose tissue and interacts with nutritional regulations in adulthood, leading to metabolic dysregulations. AIM We hypothesized that the renin-angiotensin system may play a role in the programming-induced development of visceral adipose tissue. MATERIAL AND METHODS We studied, using a model of programming of overweight and glucose intolerance, obtained by post-natal overfeeding with consecutive highfat diet, the status of plasma renin activity and mesenteric adipose renin-angiotensin system, including the recently identified (pro)renin receptor, in adult rats. RESULTS Post-natal overfeeding or high-fat feeding lead to overweight with increased visceral fat mass and adipocytes surface. When both paradigms were associated, adipocytes surface showed a disproportionate increase. A strong immunoreactivity for (pro)renin receptor was found in stromal cells. Plasma renin activity increased in programmed animals whereas (pro)renin receptor expressing cells density was stimulated by high-fat diet. There was a positive, linear relationship between plasma renin activity and (pro)renin receptor expressing cells density and adipocytes surface. CONCLUSIONS Our experiments demonstrate that association of post-natal overfeeding and high-fat diet increased plasma renin activity and adipose (pro)renin receptor expression. Such phenomenon could explain, at least in part, the associated disproportionate adipocyte hypertrophy and its accompanying increased glucose intolerance.
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Affiliation(s)
- V Achard
- Aix-Marseille University, Laboratoire d'Histologie-Embryologie, Marseille, France
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Sigmund CD. Divergent mechanism regulating fluid intake and metabolism by the brain renin-angiotensin system. Am J Physiol Regul Integr Comp Physiol 2011; 302:R313-20. [PMID: 22049229 DOI: 10.1152/ajpregu.00575.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this review is two-fold. First, I will highlight recent advances in our understanding of the mechanisms regulating angiotensin II (ANG II) synthesis in the brain, focusing on evidence that renin is expressed in the brain and is expressed in two forms: a secreted form, which may catalyze extracellular ANG I generation from glial or neuronal angiotensinogen (AGT), and an intracellular form, which may generate intracellular ANG in neurons that may act as a neurotransmitter. Second, I will discuss recent studies that advance the concept that the renin-angiotensin system (RAS) in the brain not only is a potent regulator of blood pressure and fluid intake but may also regulate metabolism. The efferent pathways regulating the blood pressure/dipsogenic effects and the metabolic effects of elevated central RAS activity appear different, with the former being dependent upon the hypothalamic-pituitary-adrenal axis, and the latter being dependent upon an interaction between the brain and the systemic (or adipose) RAS.
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Affiliation(s)
- Curt D Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, 52242, USA.
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Chou CL, Lai YH, Lin TY, Lee TJ, Fang TC. Aliskiren prevents and ameliorates metabolic syndrome in fructose-fed rats. Arch Med Sci 2011; 7:882-8. [PMID: 22291836 PMCID: PMC3258813 DOI: 10.5114/aoms.2011.25566] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 12/02/2010] [Accepted: 12/07/2010] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION The renin-angiotensin system plays a major role in the pathogenesis of metabolic syndrome. The objective of this study was to examine the effects of aliskiren, a direct renin inhibitor, on the metabolic syndrome of fructose-fed rats. MATERIAL AND METHODS Male Sprague-Dawley rats were divided into 4 groups (n = 6 for each group). Group Con: rats were fed a standard chow diet for 8 weeks, group Fru: rats were fed a high fructose diet (60% fructose) for 8 weeks, group FruA: rats were fed a high fructose diet and were co-infused with aliskiren (100 mg/kg/day), and group FruB: rats were treated as group Fru, but aliskiren was administered 4 weeks later. Systolic blood pressure (SBP), homeostasis model assessment-insulin resistance (HOMA-IR), and blood profiles were measured. RESULTS By the end of week 4 and 8 of a high fructose diet, SBP had increased significantly from 111 ±5 to 142 ±4 and 139 ±5 mmHg (p < 0.05), respectively. A high fructose diet significantly increased HOMA-IR from baseline (6.15 ±1.59) to 21.25 ±2.08 and 21.28 ±3.1 (p < 0.05) at week 4 and 8, respectively, and significantly induced metabolic syndrome. Concurrent aliskiren treatment prevented the development of hypertension and metabolic syndrome in fructose-fed rats. When fructose-induced hypertension was established, subsequent aliskiren treatment for 4 weeks reversed the elevated SBP and ameliorated metabolic syndrome. There were no significant differences in food, water intake, urine flow or body weight gain among groups. CONCLUSIONS Aliskiren not only prevents but also ameliorates metabolic syndrome in fructose-fed rats.
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Affiliation(s)
- Chu-Lin Chou
- Institute of Medical Sciences, Medical College, Tzu-Chi University, Hualien, Taiwan
- Department of Medicine, Hualien Armed Forces General Hospital, Hualien, Taiwan
| | - Yu-Hsien Lai
- Division of Nephrology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Teng-Yi Lin
- Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Tony J.F. Lee
- Institutes of Life Sciences, Pharmacology and Toxicology, and Medical Sciences, Tzu-Chi University, Hualien, Taiwan
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Te-Chao Fang
- Institute of Medical Sciences, Medical College, Tzu-Chi University, Hualien, Taiwan
- Division of Nephrology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- Department of Medicine, Medical College, Tzu Chi University, Hualien, Taiwan
- Corresponding author: Te-Chao Fang MD, PhD, Division of Nephrology Buddhist Tzu Chi General Hospital, 707, Section 3, Chung Yang Rd, Hualien 97004, Taiwan, Phone: +886-3-856-1825, ext. 2253, Fax: +886-3-856-4673. E-mail:
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Rodríguez-Penas D, Feijóo-Bandín S, Lear PV, Mosquera-Leal A, García-Rúa V, Otero MF, Rivera M, Gualillo O, González-Juanatey JR, Lago F. Aliskiren affects fatty-acid uptake and lipid-related genes in rodent and human cardiomyocytes. Biochem Pharmacol 2011; 82:491-504. [DOI: 10.1016/j.bcp.2011.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 05/13/2011] [Accepted: 05/18/2011] [Indexed: 12/13/2022]
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Eckertova M, Ondrejcakova M, Krskova K, Zorad S, Jezova D. Subchronic treatment of rats with oxytocin results in improved adipocyte differentiation and increased gene expression of factors involved in adipogenesis. Br J Pharmacol 2011; 162:452-63. [PMID: 20846187 DOI: 10.1111/j.1476-5381.2010.01037.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Treatment with thiazolidinediones, insulin-sensitizing drugs, enhances adipogenesis, which may result in unwanted increase in adiposity. Based on the suggested metabolic effects of oxytocin, the aims of the present study were to: (i) determine whether chronic treatment with oxytocin exerts positive effects on white adipose tissue growth without increasing adiposity; (ii) investigate possible mechanisms of action of oxytocin by measuring the level of gene expression of adipogenic factors; and (iii) test the hypothesis that oxytocin's effect on adipose tissue involves specific activation of eukaryotic elongation factor 2 (eEF2). EXPERIMENTAL APPROACH Adult rats were subcutaneously treated with oxytocin (3.6 µg·100 g⁻¹ body weight day⁻¹) via osmotic minipumps for 2 weeks. Adipocytes from epididymal adipose tissue were isolated and their size evaluated by light microscopy. Gene expression of adipogenic and angiogenic factors was determined by real-time PCR and dephosphorylation of eEF2 by immunoblotting. KEY RESULTS Oxytocin treatment decreased the diameter of adipocytes and increased the epididymal adipose tissue protein content without changing the adipose tissue mass. Increases in fatty acid binding protein, peroxisome proliferator-activated receptor γ, insulin-sensitive glucose transporter 4, leptin and CD31 mRNA levels were noted in the epididymal and/or retroperitoneal fat tissue of oxytocin-treated rats. Oxytocin enhanced the dephosphorylation of eEF2 in the epididymal adipose tissue. CONCLUSIONS AND IMPLICATIONS The present results demonstrate that subchronic treatment with oxytocin induces adipogenic and angiogenic effects and that the eEF2 signalling pathway is involved in these effects of oxytocin on adipose tissue in vivo. These findings are likely to motivate further research and indicate new approaches for modulating adipose tissue morphology and metabolism.
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Affiliation(s)
- Miroslava Eckertova
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
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Diet-induced obesity suppresses ghrelin in rat gastrointestinal tract and serum. Mol Cell Biochem 2011; 355:299-308. [DOI: 10.1007/s11010-011-0867-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/28/2011] [Indexed: 12/14/2022]
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St-Jacques R, Toulmond S, Auger A, Binkert C, Cromlish W, Fischli W, Harris J, Hess P, Jie Lan, Liu S, Riendeau D, Steiner B, Percival MD. Characterization of a stable, hypertensive rat model suitable for the consecutive evaluation of human renin inhibitors. J Renin Angiotensin Aldosterone Syst 2011; 12:133-45. [PMID: 21393355 DOI: 10.1177/1470320310392618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION The hypertensive double-transgenic (dTG) rat strain, expressing human renin and angiotensinogen, develops severe hypertension and organ damage and 50% of individuals die by 7 weeks of age. Here, we characterise a variation of this model in which animals present stable hypertension. MATERIALS AND METHODS The effect of renin-angiotensin system blockers on blood pressure was determined with adult dTG rats treated with enalapril from 3 to 12 weeks of age. Tissue expression levels of renin and angiotensinogen were determined in dTG rats and rhesus monkeys by quantitative PCR. RESULTS Upon withdrawal from enalapril, mean arterial pressure (MAP) rose to 160-180 mmHg, with 95% of the female dTG rats surviving for 6 to 12 months, In Sprague-Dawley (SD) rats and rhesus monkeys, renin mRNA was absent or weakly expressed in most tissues, except for the kidneys and adrenals. In dTG rats, human renin expression was high in many additional tissues. The expression of human angiotensinogen in dTG rats followed a similar tissue pattern to SD and rhesus monkey angiotensinogen. Oral dosing of aliskiren, enalapril or losartan provided a similar maximal reduction in MAP and duration of efficacy in telemetrised dTG rats. CONCLUSIONS Enalapril-pretreated dTG rats are suitable for long-term MAP monitoring and sequential evaluation of human renin inhibitors.
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Affiliation(s)
- René St-Jacques
- Department of Pharmacology, Merck Frosst Centre for Therapeutic Research, Canada
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Grobe JL, Buehrer BA, Hilzendeger AM, Liu X, Davis DR, Xu D, Sigmund CD. Angiotensinergic signaling in the brain mediates metabolic effects of deoxycorticosterone (DOCA)-salt in C57 mice. Hypertension 2011; 57:600-7. [PMID: 21263123 DOI: 10.1161/hypertensionaha.110.165829] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Low-renin hypertension accounts for ≈ 25% of essential hypertensive patients. It is modeled in animals by chronic delivery of deoxycorticosterone acetate and excess dietary sodium (the DOCA-salt model). Previous studies have demonstrated that DOCA-salt hypertension is mediated through activation of the brain renin-angiotensin system. Here, we demonstrate robust metabolic phenotypes of DOCA-salt treatment. Male C57BL/6J mice (6 to 8 weeks old) received a subcutaneous pellet of DOCA (50 mg for 21 days) and were offered a 0.15 mol/L NaCl drink solution in addition to regular chow and tap water. Treatment resulted in mild hypertension, a blunting of weight gain, gross polydipsia, polyuria, and sodium intake, alterations in urinary sodium and potassium turnover, and serum sodium retention. Most strikingly, DOCA-salt mice exhibited no difference in food intake but did exhibited a large elevation in basal metabolic rate. Normalization of blood pressure by hydralazine (500 mg/L in drink solutions) attenuated the hydromineral phenotypes and renal renin suppression effects of DOCA-salt but had no effect on the elevated metabolic rate. In contrast, intracerebroventricular infusion of the angiotensin II type 1 receptor antagonist losartan (5 μg/h) attenuated the elevation in metabolic rate with DOCA-salt treatment. Together, these data illustrate the necessity of angiotensinergic signaling within the brain, independent of blood pressure alterations, in the metabolic consequences of DOCA-salt treatment.
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Affiliation(s)
- Justin L Grobe
- Department of Pharmacology, Roy J and Lucille A. Carver College of Medicine, University of Iowa, 3181 MERF, 375 Newton Rd, Iowa City, IA 52242, USA.
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Thornton SN. Angiotensin inhibition and longevity: a question of hydration. Pflugers Arch 2010; 461:317-24. [PMID: 21165644 DOI: 10.1007/s00424-010-0911-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 11/25/2010] [Accepted: 11/29/2010] [Indexed: 01/07/2023]
Abstract
With the advancement of medical and investigative science, it is somewhat surprising that although it is possible to stabilise medical patients with hypertension and the associated kidney dysfunction, obesity, diabetes and even cancer, there is still no clear method of significantly reducing these chronic disease pathologies, and thus, extending life expectancy. There is one hormone common to these pathologies, the antagonism of which goes some way to clinical improvements, and this is angiotensin, which is released during hypovolaemia. Angiotensin antagonists are used to treat many of these pathologies, and it has been shown in the obesity literature that angiotensin antagonists decrease weight, but also increase the drinking of water. Increased cellular hydration, and hence, improved mitochondrial metabolism could be one of the mechanisms for the reduction in weight seen in these studies, as well as for reducing the other pathologies, all showing metabolic dysfunction. It appears that the application of straightforward physiological regulation might be an appropriate medical approach to the prevention of hypertension, kidney disease, obesity, diabetes and cancer, and thus, to an increased life expectancy.
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Abstract
PURPOSE OF REVIEW In contrast to previous understanding, adipocytes are now known to produce an array of factors collectively termed 'adipokines', several of which have effects on the cardiovascular system. The marked rise in prevalence of obesity warrants investigation into the role of adipocyte-derived factors in the regulation of blood pressure. For example, dysregulated production of specific adipokines in the setting of obesity may contribute to hypertension commonly experienced in obese patients. This editorial highlights current concepts for regulation of adipokine production by adipocytes and their potential role in blood pressure regulation. RECENT FINDINGS Adipocytes synthesize and release several factors that have been linked to blood pressure control, including adiponectin, leptin, angiotensin, perivascular relaxation factors and resistin. Increasing evidence suggests that aberrant production and release of these factors from adipocytes may contribute to the high prevalence of hypertension in the obese population. However, additional studies are warranted to define precise mechanisms for blood pressure regulation by these factors, and to delineate their role in obesity-related hypertension. SUMMARY Studies aimed at determining the role of adipocyte-derived factors in blood pressure regulation during normal physiology and in the setting of obesity are needed.
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Chaudhary K, Nistala R, Whaley-Connell A. Is there a future for direct renin inhibitors? Expert Opin Investig Drugs 2010; 19:653-61. [DOI: 10.1517/13543781003781906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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