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Russo I. The prothrombotic tendency in metabolic syndrome: focus on the potential mechanisms involved in impaired haemostasis and fibrinolytic balance. SCIENTIFICA 2012; 2012:525374. [PMID: 24278711 PMCID: PMC3820496 DOI: 10.6064/2012/525374] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 08/27/2012] [Indexed: 05/09/2023]
Abstract
The metabolic syndrome is a clinical disorder characterized by impairment of glucose metabolism, increased arterial blood pressure, and abdominal obesity. The presence of these clinical features exposes patients to a high risk of atherothrombotic cardiovascular events. The pathogenesis of atherothrombosis in the metabolic syndrome is multifactorial, requiring a close relationship among the main components of the metabolic syndrome, including insulin resistance, alterations of glycaemic and lipid pattern, haemodynamic impairment, and early appearance of endothelial dysfunction. Furthermore, haemostatic alterations involving coagulation balance, fibrinolysis, and platelet function play a relevant role both in the progression of the arterial wall damage and in acute vascular events. The mechanisms linking abdominal obesity with prothrombotic changes in the metabolic syndrome have been identified and partially elucidated on the basis of alterations of each haemostatic variable and defined through the evidence of peculiar dysfunctions in the endocrine activity of adipose tissue responsible of vascular impairment, prothrombotic tendency, and low-grade chronic inflammation. This paper will focus on the direct role of adipose tissue on prothrombotic tendency in patients affected by metabolic syndrome, with adipocytes being able to produce and/or release cytokines and adipokines which deeply influence haemostatic/fibrinolytic balance, platelet function, and proinflammatory state.
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Affiliation(s)
- Isabella Russo
- Internal Medicine and Metabolic Disease Unit, Department of Clinical and Biological Sciences of the Turin University, San Luigi Gonzaga Hospital, 10043 Orbassano, Italy
- *Isabella Russo:
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Fletcher SJ, Kalupahana NS, Soltani-Bejnood M, Kim JH, Saxton AM, Wasserman DH, De Taeye B, Voy BH, Quignard-Boulange A, Moustaid-Moussa N. Transgenic mice overexpressing Renin exhibit glucose intolerance and diet-genotype interactions. Front Endocrinol (Lausanne) 2012; 3:166. [PMID: 23308073 PMCID: PMC3538348 DOI: 10.3389/fendo.2012.00166] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 12/02/2012] [Indexed: 01/21/2023] Open
Abstract
Numerous animal and clinical investigations have pointed to a potential role of the renin-angiotensin system (RAS) in the development of insulin resistance and diabetes in conditions of expanded fat mass. However, the mechanisms underlying this association remain unclear. We used a transgenic mouse model overexpressing renin in the liver (RenTgMK) to examine the effects of chronic activation of RAS on adiposity and insulin sensitivity. Hepatic overexpression of renin resulted in constitutively elevated plasma angiotensin II (four- to six-fold increase vs. wild-type, WT). Surprisingly, RenTgMK mice developed glucose intolerance despite low levels of adiposity and insulinemia. The transgenics also had lower plasma triglyceride levels. Glucose intolerance in transgenic mice fed a low-fat diet was comparable to that observed in high-fat fed WT mice. These studies demonstrate that overexpression of renin and associated hyperangiotensinemia impair glucose tolerance in a diet-dependent manner and further support a consistent role of RAS in the pathogenesis of diabetes and insulin resistance, independent of changes in fat mass.
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Affiliation(s)
- Sarah J. Fletcher
- Genome Science and Technology Program, University of TennesseeKnoxville, TN, USA
| | - Nishan S. Kalupahana
- Department of Physiology, Faculty of Medicine, University of PeradeniyaPeradeniya, Sri Lanka
| | | | - Jung Han Kim
- Department of Pharmacology, Physiology and Toxicology, School of Medicine, Marshall UniversityHuntington, WV, USA
| | - Arnold M. Saxton
- Department of Animal Science, University of TennesseeKnoxville, TN, USA
| | - David H. Wasserman
- Department of Molecular Physiology and Biophysics, School of Medicine and Mouse Metabolic Phenotyping Center, Vanderbilt UniversityNashville, TN, USA
| | - Bart De Taeye
- Department of Molecular Physiology and Biophysics, School of Medicine and Mouse Metabolic Phenotyping Center, Vanderbilt UniversityNashville, TN, USA
| | - Brynn H. Voy
- Department of Animal Science, University of TennesseeKnoxville, TN, USA
| | | | - Naima Moustaid-Moussa
- Nutritional Sciences, Texas Tech UniversityLubbock, TX, USA
- *Correspondence: Naima Moustaid-Moussa, Nutritional Sciences, Texas Tech University, 1301, Akron Street, Lubbock, TX 79423, USA. e-mail:
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Li S, Nitsos I, Polglase GR, Braun T, Moss TJM, Newnham JP, Challis JRG. The Effects of Dexamethasone Treatment in Early Gestation on Hypothalamic–Pituitary–Adrenal Responses and Gene Expression at 7 Months of Postnatal Age in Sheep. Reprod Sci 2011; 19:260-70. [DOI: 10.1177/1933719111418374] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Shaofu Li
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
- Women and Infants Research Foundation of Western Australia, Perth, Australia
| | - Ilias Nitsos
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
| | - Graeme R. Polglase
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
- The Ritchie Centre, Monash Institute of Medical Research, Victoria, Australia
- Department of Obstetrics and Gynecology, Monash University, Victoria, Australia
| | - Thorsten Braun
- Department of Obstetrics, Charité University Berlin, Berlin, Germany
- Department of Physiology, University of Toronto, Toronto , Canada
- Department of Obstetrics and Gynecology, University of Toronto, Toronto, Canada
| | - Timothy J. M. Moss
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
- The Ritchie Centre, Monash Institute of Medical Research, Victoria, Australia
- Department of Obstetrics and Gynecology, Monash University, Victoria, Australia
| | - John P. Newnham
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
- Women and Infants Research Foundation of Western Australia, Perth, Australia
| | - John R. G. Challis
- School of Women’s and Infants’ Health, The University of Western Australia, Western Australia, Australia
- Department of Physiology, University of Toronto, Toronto , Canada
- Department of Obstetrics and Gynecology, University of Toronto, Toronto, Canada
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Sympathetic nervous system in obesity-related hypertension: mechanisms and clinical implications. Hypertens Res 2011; 35:4-16. [PMID: 22048570 DOI: 10.1038/hr.2011.173] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Obesity markedly increases the risk of hypertension and cardiovascular disease, which may be related to activation of the sympathetic nervous system (SNS). Sympathetic overactivity directly and indirectly contributes to blood pressure (BP) elevation in obesity, including stimulation of the renin-angiotensin-aldosterone system (RAAS). The adipocyte-derived peptide leptin suppresses appetite, increases thermogenesis, but also raises SNS activity and BP. Obese individuals exhibit hyperleptinemia but are resistant to its appetite-suppressing actions. Interestingly, animal models of obesity exhibit preserved sympathoexcitatory and pressor actions of leptin, despite resistance to its anorexic and metabolic actions, suggesting selective leptin resistance. Disturbance of intracellular signaling at specific hypothalamic neural networks appears to underlie selective leptin resistance. Delineation of these pathways should lead to novel approaches to treatment. In the meantime, treatment of obesity-hypertension has relied on antihypertensive drugs. Although sympathetic blockade is mechanistically attractive in obesity-hypertension, in practice its effects are disappointing because of adverse metabolic effects and inferior outcomes. On the basis of subgroup analyses of obese patients in large randomized clinical trials, drugs such as diuretics and RAAS blockers appear superior in preventing cardiovascular events in obesity--hypertension. An underused alternative approach to obesity-hypertension is induction of weight loss, which reduces circulating leptin and insulin, partially reverses resistance to these hormones, decreases sympathetic activation and improves BP and other risk factors. Though weight loss induced by lifestyle is often modest and transient, carefully selected pharmacological weight loss therapies can produce substantial and sustained antihypertensive effects additive to lifestyle interventions.
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Ferris WF, Crowther NJ. Once fat was fat and that was that: our changing perspectives on adipose tissue. Cardiovasc J Afr 2011; 22:147-54. [PMID: 21713306 PMCID: PMC3721932 DOI: 10.5830/cvja-2010-083] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Abstract Past civilisations saw excess body fat as a symbol of wealth and prosperity as the general population struggled with food shortages and famine. Nowadays it is recognised that obesity is associated with co-morbidities such as cardiovascular disease and diabetes. Our views on the roll of adipose tissue have also changed, from being solely a passive energy store, to an important endocrine organ that modulates metabolism, immunity and satiety. The relationship between increased visceral adiposity and obesity-related co-morbidities has lead to the recognition that variation in fat distribution contributes to ethnic differences in the prevalence of obesity-related diseases. Our current negative view of adipose tissue may change with the use of pluripotent adipose-derived stromal cells, which may lead to future autologous stem cell therapies for bone, muscle, cardiac and cartilage disorders. Here, we briefly review the concepts that adipose tissue is an endocrine organ, that differences in body fat distribution underline the aetiology of obesity-related co-morbidities, and the use of adipose-derived stem cells for future therapies.
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Affiliation(s)
- W F Ferris
- Division of Endocrinology, Department of Medicine, Faculty of Health Sciences, University of Stellenbosch, Stellenbosch, South Africa.
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Vykoukal D, Davies MG. Vascular biology of metabolic syndrome. J Vasc Surg 2011; 54:819-31. [PMID: 21439758 PMCID: PMC3136643 DOI: 10.1016/j.jvs.2011.01.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 01/02/2011] [Accepted: 01/06/2011] [Indexed: 12/20/2022]
Abstract
The metabolic syndrome is a constellation of clinical risk factors comprising atherogenic dyslipidemia (low high-density lipoprotein and high triglycerides levels), elevated blood pressure, elevated plasma glucose, a prothrombotic state, and a proinflammatory state accompanied by an increased risk for cardiovascular disease and type 2 diabetes mellitus. The adipose tissue of obese humans contains increased numbers of macrophages, and once activated, these macrophages are responsible for the expression of most of the tissue's tumor necrosis factor (TNF)-α and interleukin (IL)-6. Chronic inflammation associated with visceral obesity induces altered lipoprotein metabolism and insulin resistance in the liver. Adipocytes secrete a variety of hormones, cytokines, growth factors, and other bioactive substances, conceptualized as adipocytokines, including plasminogen activator inhibitor 1 (PAI-1), TNF-α, leptin, and adiponectin. The dysregulation of these adipokines contributes to the pathogenesis of obesity. Adipose tissue-resident macrophages and adipocytes in the adipose tissue combined with the consequences of hyperglycemia, altered lipoproteins, and hyperinsulinemia in the vasculature and within organ microcirculation lead to dysfunctional endothelia and a proinflammatory state. Metabolic syndrome thus represents a combination of synergistic vascular pathologies that lead to an accelerated atherogenic state that compromises the ability of the patient to satisfactorily respond to humoral, cellular, and mechanical stresses.
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Affiliation(s)
- Daynene Vykoukal
- Vascular Biology and Therapeutics Program, The Methodist Hospital Research Institute, The Methodist Hospital, Houston, TX77030, USA
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57
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Soya protein attenuates abnormalities of the renin–angiotensin system in adipose tissue from obese rats. Br J Nutr 2011; 107:36-44. [DOI: 10.1017/s0007114511002595] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Several metabolic disturbances during obesity are associated with adipose tissue-altered functions. Adipocytes contain the renin–angiotensin system (RAS), which regulates signalling pathways that control angiogenesis via Akt in an autocrine fashion. Soya protein (Soy) consumption modifies the gene expression pattern in adipose tissue, resulting in an improved adipocyte function. Therefore, the aim of the present work is to study whether dietary Soy regulates the expression of RAS and angiogenesis-related genes and its association with the phosphorylated state of Akt in the adipose tissue of obese rats. Animals were fed a 30 % Soy or casein (Cas) diet containing 5 or 25 % fat for 160 d. mRNA abundance was studied in the adipose tissue, and Akt phosphorylation and hormone release were measured in the primary adipocyte culture. The present results show that Soy treatment in comparison with Cas consumption induces lower angiotensin release and increased insulin-stimulated Akt activation in adipocytes. Furthermore, Soy consumption varies the expression of RAS and angiogenesis-related genes, which maintain cell size and vascularity in the adipose tissue of rats fed a high-fat diet. Thus, adipocyte hypertrophy and impaired angiogenesis, which are frequently observed in dysfunctional adipose tissue, were avoided by consuming dietary Soy. Taken together, these findings suggest that Soy can be used as a dietary strategy to preserve adipocyte functionality and to prevent obesity abnormalities.
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58
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Musk GC, Polglase GR, Bunnell JB, McLean CJ, Nitsos I, Song Y, Pillow JJ. High positive end-expiratory pressure during high-frequency jet ventilation improves oxygenation and ventilation in preterm lambs. Pediatr Res 2011; 69:319-24. [PMID: 21178822 DOI: 10.1203/pdr.0b013e31820bbdf5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Increasing positive end-expiratory pressure (PEEP) is advocated to recruit alveoli during high-frequency jet ventilation (HFJV), but its effect on cardiopulmonary physiology and lung injury is poorly documented. We hypothesized that high PEEP would recruit alveoli and reduce lung injury but compromise pulmonary blood flow (PBF). Preterm lambs of anesthetized ewes were instrumented, intubated, and delivered by cesarean section after instillation of surfactant. HFJV was commenced with a PEEP of 5 cm H2O. Lambs were allocated randomly at delivery to remain on constant PEEP (PEEPconst, n = 6) or to recruitment via stepwise adjustments in PEEP (PEEPadj, n = 6) to 12 cm H2O then back to 8 cm H2O over the initial 60 min. PBF was measured continuously while ventilatory parameters and arterial blood gases were measured at intervals. At postmortem, in situ pressure-volume deflation curves were recorded, and bronchoalveolar lavage fluid and lung tissue were obtained to assess inflammation. PEEPadj lambs had lower pressure amplitude, fractional inspired oxygen concentration, oxygenation index, and PBF and more compliant lungs. Inflammatory markers were lower in the PEEPadj group. Adjusted PEEP during HFJV improves oxygenation and lung compliance and reduces ventilator requirements despite reducing pulmonary perfusion.
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Affiliation(s)
- Gabrielle C Musk
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia 6009, Australia.
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Lopez-Jaramillo P, Lahera V, Lopez-Lopez J. Epidemic of cardiometabolic diseases: a Latin American point of view. Ther Adv Cardiovasc Dis 2011; 5:119-31. [PMID: 21406494 DOI: 10.1177/1753944711403189] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Poor early nutrition has varying effects on subsequent cardiometabolic disease (CMD) rates. Fetal and neonatal periods are critical for the development and growth of the systems involved in CMD. The increased rates of hypertension, metabolic syndrome, diabetes mellitus type 2, renal failure and heart failure observed nowadays in Latin America could be the result of the discrepancy between the nutritional environment during fetal and early life and the adult environment. This discrepancy causes a mismatch between the fetal programming of the subject and its adult circumstances created by the imposition of new life styles. The two largest international studies on cardiovascular risk factors for a first myocardial infarction (INTERHEART) and stroke (INTERSTROKE) demonstrated that in Latin America the factor with the highest attributable population risk was abdominal obesity. The conflict between the earlier programming and the later presence of abdominal obesity produced a higher sensitivity of this population to develop a state of low-degree inflammation, insulin resistance and the epidemic of CMD to lower levels of abdominal adiposity. The relative roles played by genetic and environmental factors and the interaction between the two are the still subjects of great debate. We have reviewed the relationship between maternal malnutrition, early growth restriction, epigenetic adaptations, and the later occurrence of abdominal obesity and CMD in Latin America.
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Affiliation(s)
- Patricio Lopez-Jaramillo
- Research Direction, Fundacion Oftalmologica de Santander-Clinica Carlos Ardila-Lulle, Floridablanca, Santander, Colombia.
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Yvan-Charvet L, Quignard-Boulangé A. Role of adipose tissue renin–angiotensin system in metabolic and inflammatory diseases associated with obesity. Kidney Int 2011; 79:162-8. [DOI: 10.1038/ki.2010.391] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Okada S, Kozuka C, Masuzaki H, Yasue S, Ishii-Yonemoto T, Tanaka T, Yamamoto Y, Noguchi M, Kusakabe T, Tomita T, Fujikura J, Ebihara K, Hosoda K, Sakaue H, Kobori H, Ham M, Lee YS, Kim JB, Saito Y, Nakao K. Adipose tissue-specific dysregulation of angiotensinogen by oxidative stress in obesity. Metabolism 2010; 59:1241-51. [PMID: 20045538 PMCID: PMC2891233 DOI: 10.1016/j.metabol.2009.11.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 02/07/2023]
Abstract
Adipose tissue expresses all components of the renin-angiotensin system including angiotensinogen (AGT). Recent studies have highlighted a potential role of AGT in adipose tissue function and homeostasis. However, some controversies surround the regulatory mechanisms of AGT in obese adipose tissue. In this context, we here demonstrated that the AGT messenger RNA (mRNA) level in human subcutaneous adipose tissue was significantly reduced in obese subjects as compared with nonobese subjects. Adipose tissue AGT mRNA level in obese mice was also lower as compared with their lean littermates; however, the hepatic AGT mRNA level remained unchanged. When 3T3-L1 adipocytes were cultured for a long period, the adipocytes became hypertrophic with a marked increase in the production of reactive oxygen species. Expression and secretion of AGT continued to decrease during the course of adipocyte hypertrophy. Treatment of the 3T3-L1 and primary adipocytes with reactive oxygen species (hydrogen peroxide) or tumor necrosis factor alpha caused a significant decrease in the expression and secretion of AGT. On the other hand, treatment with the antioxidant N-acetyl cysteine suppressed the decrease in the expression and secretion of AGT in the hypertrophied 3T3-L1 adipocytes. Finally, treatment of obese db/db mice with N-acetyl cysteine augmented the expression of AGT in the adipose tissue, but not in the liver. The present study demonstrates for the first time that oxidative stress dysregulates AGT in obese adipose tissue, providing a novel insight into the adipose tissue-specific interaction between the regulation of AGT and oxidative stress in the pathophysiology of obesity.
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Affiliation(s)
- Sadanori Okada
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
- First Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Chisayo Kozuka
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Hiroaki Masuzaki
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
- Corresponding author. Division of Endocrinology and Metabolism, Second Department of Internal Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan. Tel.: +81 98 895 1145; fax: +81 98 895 1415. (H. Masuzaki)
| | - Shintaro Yasue
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Takako Ishii-Yonemoto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Tomohiro Tanaka
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Yuji Yamamoto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Michio Noguchi
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Toru Kusakabe
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Tsutomu Tomita
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Junji Fujikura
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Ken Ebihara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Kiminori Hosoda
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Hiroshi Sakaue
- Department of Nutrition and Metabolism, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan
| | - Hiroyuki Kobori
- Departments of Medicine and Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, New Orleans, LA 70112-2699, USA
| | - Mira Ham
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 110-744, South Korea
| | - Yun Sok Lee
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 110-744, South Korea
| | - Jae Bum Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 110-744, South Korea
| | - Yoshihiko Saito
- First Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Kazuwa Nakao
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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Carvalho CR, Bueno AA, Mattos AM, Biz C, de Oliveira C, Pisani LP, Ribeiro EB, Oller do Nascimento CM, Oyama LM. Fructose alters adiponectin, haptoglobin and angiotensinogen gene expression in 3T3-L1 adipocytes. Nutr Res 2010; 30:644-9. [DOI: 10.1016/j.nutres.2010.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 06/04/2010] [Accepted: 06/17/2010] [Indexed: 11/30/2022]
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Linkage of angiotensinogen gene polymorphisms with hypertension in a sibling study of Hong Kong Chinese. J Hypertens 2010; 28:1203-9. [PMID: 20216084 DOI: 10.1097/hjh.0b013e3283384b07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The angiotensinogen gene has been linked with human essential hypertension in whites but the relationship in Asian populations has been less consistent. This study aimed to examine genetic associations between hypertension and the M235T, T174M, and G-217A polymorphisms of the angiotensinogen gene in Chinese siblings. METHODS We studied members of 126 families with a hypertensive proband, including 434 siblings, of which 178 were hypertensive. Parental history of hypertension was recorded. The M235T, T174M, and G-217A polymorphisms were examined using a microarray method, validated by sequencing. The transmission disequilibrium test was applied to identify whether the genetic polymorphism loci were related to hypertension. Haplotype analysis of the combined polymorphisms was applied using the TRANSMIT program. Linkage study was conducted by applying the affected pedigree member method. RESULTS A significant overtransmission was observed for the T235 allele at the M235T polymorphism and hypertension (chi2 = 4.41, P = 0.036) but not for the T174M and G-217A polymorphisms. The haplotype analysis showed a significant association with the haplotypes of paired markers (T174 and T235) with chi2 value of 8.131 (P = 0.004; global test chi2 = 9.131, P = 0.028). Linkage between M235T and hypertension was detected (T = -2.25, P = 0.019), and a tendency for linkage with central obesity-related hypertension was found for the M235T and T174M polymorphisms (P = 0.0087 and P = 0.01). CONCLUSION The M235T and T174M variants, especially the T235 allele, contribute to an increased risk of hypertension in these Chinese patients.
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Kim S, Soltani-Bejnood M, Quignard-Boulange A, Massiera F, Teboul M, Ailhaud G, Kim JH, Moustaid-Moussa N, Voy BH. The adipose renin-angiotensin system modulates systemic markers of insulin sensitivity and activates the intrarenal renin-angiotensin system. J Biomed Biotechnol 2010; 2006:27012. [PMID: 17489015 PMCID: PMC1698261 DOI: 10.1155/jbb/2006/27012] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Background. The adipose tissue
renin-angiotensin system (RAS) contributes to regulation of fat mass and may also impact systemic functions such as blood pressure and metabolism. Methods and results. A panel of mouse models including mice lacking angiotensinogen, Agt (Agt-KO), mice expressing Agt solely in adipose tissue (aP2-Agt/Agt-KO), and mice overexpressing Agt in adipose tissue (aP2-Agt) was studied. Total body weight, epididymal fat pad weight, and circulating levels of leptin, insulin, and resistin were significantly decreased in Agt-KO mice, while plasma adiponectin levels were increased. aP2-Agt mice exhibited increased adiposity and
plasma leptin and insulin levels compared to wild type (WT) controls. Angiotensinogen and type I Ang II receptor protein levels were also elevated in kidney of aP2-Agt mice. Conclusion. These findings demonstrate that alterations in
adipose RAS activity significantly impact both local and systemic physiology in a way that may contribute to the detrimental health effects of obesity.
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Affiliation(s)
- Suyeon Kim
- Department of Nutrition and Agricultural Experiment Station, University of Tennessee, Knoxville, TN 37996, USA
| | - Morvarid Soltani-Bejnood
- Department of Nutrition and Agricultural Experiment Station, University of Tennessee, Knoxville, TN 37996, USA
| | | | | | | | | | - Jung Han Kim
- Department of Nutrition and Agricultural Experiment Station, University of Tennessee, Knoxville, TN 37996, USA
| | - Naima Moustaid-Moussa
- Department of Nutrition and Agricultural Experiment Station, University of Tennessee, Knoxville, TN 37996, USA
| | - Brynn H. Voy
- Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- *Brynn H. Voy:
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65
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Psoriasis and systemic inflammatory diseases: potential mechanistic links between skin disease and co-morbid conditions. J Invest Dermatol 2010; 130:1785-96. [PMID: 20445552 DOI: 10.1038/jid.2010.103] [Citation(s) in RCA: 540] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Psoriasis is now classified as an immune-mediated inflammatory disease (IMID) of the skin. It is being recognized that patients with various IMIDs, including psoriasis, are at higher risk of developing "systemic" co-morbidities, e.g., cardiovascular disease (CVD), metabolic syndrome, and overt diabetes. In non-psoriatic individuals, the pathophysiology of obesity, aberrant adipocyte metabolism, diabetes, and CVDs involves immune-mediated or inflammatory pathways. IMIDs may impact these co-morbid conditions through shared genetic risks, common environmental factors, or common inflammatory pathways that are co-expressed in IMIDs and target organs. Given that pathogenic immune pathways in psoriasis are now well worked out and a large number of inflammatory mediators have been identified in skin lesions, in this review we will consider possible mechanistic links between skin inflammation and increased risks of (1) obesity or metabolic alterations and (2) CVD. In particular, we will discuss how well-established risk factors for CVD can originate from inflammation in other tissues.
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66
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Fogari R, Zoppi A, Corradi L, Preti P, Mugellini A, Lazzari P, Derosa G. Effect of body weight loss and normalization on blood pressure in overweight non-obese patients with stage 1 hypertension. Hypertens Res 2010; 33:236-42. [PMID: 20075930 DOI: 10.1038/hr.2009.220] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We evaluated the effects of body weight (BW) loss on blood pressure (BP) in overweight non-obese patients with stage 1 hypertension. We enrolled 376 overweight (body mass index (BMI) >or=25 and <30 kg m(-2)) stage 1 hypertensive patients in this prospective 12-month trial. Each patient received tailored, low caloric dietary advice. After 6 months, patients with a BW reduction <5% were excluded. Body weight, BMI, BP, fasting plasma glucose (FPG), fasting plasma insulin (FPI), leptin (pL), renin and aldosterone levels were evaluated at baseline and after 6 and 12 months. In 222 patients who completed the study, a mean weight reduction of 8.1 kg reduced systolic blood pressure (SBP) by 4.2 mm Hg and diastolic blood pressure (DBP) by 3.3 mm Hg (P<0.05), which was accompanied by a significant decrease in FPI, pL and aldosterone levels (P<0.05). Larger SBP/DBP reductions were observed in 106 patients with normalized BMI (-5/-4.5 mm Hg, P<0.01) compared with the 116 patients who did not become normalized (-3.3/-1.6 mm Hg). The former also presented with greater decreases in FPG, FPI, pL, renin and aldosterone levels. Of the 106 patients who had normalized BMI, 52 also had normalized BP. Clinical and metabolic characteristics of these patients were similar to those of the 56 patients who did not have normalized BP. In overweight, mild hypertensive patients, weight loss was effective in reducing BP and in reversing some endocrinologic alterations associated with being overweight. Half of the patients who had normalized BMI also had normalized BP, which could indicate that these patients essentially did not have a form of hypertension but that these effects were instead secondary to being overweight.
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Affiliation(s)
- Roberto Fogari
- Department of Internal Medicine and Therapeutics, Centro Ipertensione e Fisiopatologia Cardiovascolare, University of Pavia, Pavia, Italy.
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67
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Comparison of Early and Late Changes in Immunoglobulins and Acute Phase Reactants after Laparoscopic Adjustable Gastric Banding in Patients with Morbid Obesity. Obes Surg 2010; 20:610-5. [DOI: 10.1007/s11695-009-0061-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 12/08/2009] [Indexed: 12/28/2022]
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68
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Tugcu A, Yildirimtürk O, Tayyareci Y, Demiroglu C, Aytekin S. Evaluation of Subclinical Right Ventricular Dysfunction in Obstructive Sleep Apnea Patients Using Velocity Vector Imaging. Circ J 2010; 74:312-9. [DOI: 10.1253/circj.cj-09-0562] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aylin Tugcu
- Florence Nightingale Hospital, Division of Cardiology
| | | | | | | | - Saide Aytekin
- Florence Nightingale Hospital, Division of Cardiology
- T.C. Istanbul Bilim University, Medical Faculty, Division of Cardiology
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69
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Hankinson AL. Epidemiologic and pathophysiologic links between obesity and hypertension. CURRENT CARDIOVASCULAR RISK REPORTS 2009. [DOI: 10.1007/s12170-009-0041-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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70
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Abstract
Several reviews have highlighted the importance of local tissue production of components of the renin-angiotensin system (RAS) [Bader, M., Ganten, D., 2008. Update on tissue renin-angiotensin systems. J. Mol. Med. 86, 615-621; Krop, M., Danser, A.H., 2008. Circulating versus tissue renin-angiotensin system: on the origin of (pro)renin. Curr. Hypertens. Rep. 10, 112-118; Paul, M., Poyan Mehr, A., Kreutz, R., 2006. Physiology of local renin-angiotensin systems. Physiol. Rev. 86, 747-803]. While the concept of tissue RAS is gaining more widespread acceptance, the concept of local angiotensin II (AngII) production, acting in coordinate or independently of the endocrine RAS, continues to be debated. The primary reasons that local AngII production has been studied by many investigators are that components of the RAS are expressed by multiple cell types, and that the endocrine RAS cannot fully explain all effects of AngII. Moreover, through the development and study of genetically altered models for over-expression or knockdown of individual RAS components within specific cell types, it is becoming increasingly more evident that local RAS contribute to effects of AngII in normal physiology and disease. The purpose of this review is to define the presence and physiological significance of a local RAS in adipose tissue in relation to cardiovascular disease.
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Affiliation(s)
- Sean Thatcher
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40536-0200, USA
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71
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Yvan-Charvet L, Massiéra F, Lamandé N, Ailhaud G, Teboul M, Moustaid-Moussa N, Gasc JM, Quignard-Boulangé A. Deficiency of angiotensin type 2 receptor rescues obesity but not hypertension induced by overexpression of angiotensinogen in adipose tissue. Endocrinology 2009; 150:1421-8. [PMID: 18948399 DOI: 10.1210/en.2008-1120] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased angiotensinogen (AGT) production by white adipose tissue has been related to not only obesity but also hypertension. Several studies have highlighted the importance of the angiotensin II type 2 receptor (AT2) in the regulation of blood pressure and fat mass, but the relevance of this transporter in a physiopathological model of increased AGT production, as it occurs in obesity, has not yet been investigated. We used transgenic mice that display either a deletion of AT2 (AT2 KO), an overexpression of AGT (OVEX), or both compound mutants (KOVEX). Results demonstrated that adipocyte hypertrophy and increased lipogenic gene expression induced by adipose AGT overproduction was rescued by deletion of AT2. In line with AGT overexpression, KOVEX and OVEX mice have similar increased plasma AGT levels. However, KOVEX mice display a higher blood pressure than OVEX mice. In kidney, renin expression was clearly reduced in OVEX mice, and its expression was normalized in KOVEX mice. Taken together, we demonstrated that the loss of AT2 expression was sufficient to rescue obesity induced by adipose tissue AGT overexpression and confirmed the necessary role of AT2 for the onset of obesity in this model. Furthermore, despite a reduction of adipose mass in KOVEX, AT2 deficiency caused increased renin production, further worsening the hypertension caused by AGT overexpression.
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Affiliation(s)
- Laurent Yvan-Charvet
- Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie, Centre Biomédical des Cordeliers, Paris, France
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72
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Niemiec P, Zak I, Wita K. The M235T polymorphism of the AGT gene modifies the risk of coronary artery disease associated with the presence of hypercholesterolemia. Eur J Epidemiol 2008; 23:349-54. [PMID: 18409009 DOI: 10.1007/s10654-008-9241-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 03/23/2008] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Atherosclerosis is an inflammatory disease resulting from interactions between various genetic and non-genetic factors. Angiotensinogen gene (AGT) belongs to polymorphic candidate genes. Recent evidence show that many traditional risk factors of coronary artery disease (CAD) influence synthesis of AGT. This report focuses on the interactions between M235T polymorphism of AGT gene and traditional risk factors of CAD. MATERIAL AND METHODS 255 subjects, including 158 patients with angiographically confirmed CAD and 97 blood donors without history of cardiovascular diseases were studied. M235T polymorphism of the AGT gene was genotyped using PCR-RFLP method. To determine the possible interactions of AGT genotypes and traditional risk factors of CAD the attributable proportion due to interaction (AP) and synergy models were used. RESULTS The frequency of 235T allele carriers was significantly higher in patients than in controls (77.8 vs. 62.9, OR = 2.20, 95% CI; 1.10-4.40, P = 0.026, in multivariate logistic regression model). We found the existence of interaction between the 235T allele carrier-state and hypercholesterolemia (total cholesterol > or = 5 mmol/l) increasing the risk of CAD (SI = 3.39, 95% CI; 1.33-8.66, AP = 0.65, 95% CI; 0.39-0.91). The 235T allele also interacted with elevated LDL cholesterol levels (> or = 3 mmol/l) (AP = 0.49, 95% CI; 0.20-0.96), but not with the hypertension, overweight/ obesity and cigarette smoking. CONCLUSION The 235T allele increases the risk of CAD associated with the presence of hypercholesterolemia.
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Affiliation(s)
- Pawel Niemiec
- Department of Biochemistry and Medical Genetics, Medical University of Silesia, Medykow Str 18, 40-752 Katowice, Poland.
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73
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Lux TR, Taegtmeyer H. Aliskiren combined with losartan: Thor's hammer or Sigurd's sword? Curr Hypertens Rep 2008; 10:432-3. [PMID: 18959827 DOI: 10.1007/s11906-008-0081-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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74
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Gupte M, Boustany-Kari CM, Bharadwaj K, Police S, Thatcher S, Gong MC, English VL, Cassis LA. ACE2 is expressed in mouse adipocytes and regulated by a high-fat diet. Am J Physiol Regul Integr Comp Physiol 2008; 295:R781-8. [PMID: 18650320 DOI: 10.1152/ajpregu.00183.2008] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Adipose tissue expresses components of the renin-angiotensin system (RAS). Angiotensin converting enzyme (ACE2), a new component of the RAS, catabolizes the vasoconstrictor peptide ANG II to form the vasodilator angiotensin 1-7 [ANG-(1-7)]. We examined whether adipocytes express ACE2 and its regulation by manipulation of the RAS and by high-fat (HF) feeding. ACE2 mRNA expression increased (threefold) during differentiation of 3T3-L1 adipocytes and was not regulated by manipulation of the RAS. Male C57BL/6 mice were fed low- (LF) or high-fat (HF) diets for 1 wk or 4 mo. At 1 wk of HF feeding, adipose expression of angiotensinogen (twofold) and ACE2 (threefold) increased, but systemic angiotensin peptide concentrations and blood pressure were not altered. At 4 mo of HF feeding, adipose mRNA expression of angiotensinogen (twofold) and ACE2 (threefold) continued to be elevated, and liver angiotensinogen expression increased (twofold). However, adipose tissue from HF mice did not exhibit elevated ACE2 protein or activity. Increased expression of ADAM17, a protease responsible for ACE2 shedding, coincided with reductions in ACE2 activity in 3T3-L1 adipocytes, and an ADAM17 inhibitor decreased media ACE2 activity. Moreover, ADAM17 mRNA expression was increased in adipose tissue from 4-mo HF-fed mice, and plasma ACE2 activity increased. However, HF mice exhibited marked increases in plasma angiotensin peptide concentrations (LF: 2,141 +/- 253; HF: 6,829 +/- 1,075 pg/ml) and elevated blood pressure. These results demonstrate that adipocytes express ACE2 that is dysregulated in HF-fed mice with elevated blood pressure compared with LF controls.
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Affiliation(s)
- Manisha Gupte
- Graduate Center for Nutritional Sciences, Rm. 521b, Wethington Bldg., 900 S. Limestone, College of Medicine, Univ. of Kentucky, Lexington, KY 40536-0200, USA
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75
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Antuna-Puente B, Feve B, Fellahi S, Bastard JP. Adipokines: the missing link between insulin resistance and obesity. DIABETES & METABOLISM 2008; 34:2-11. [PMID: 18093861 DOI: 10.1016/j.diabet.2007.09.004] [Citation(s) in RCA: 471] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 09/11/2007] [Accepted: 09/14/2007] [Indexed: 02/06/2023]
Abstract
White adipose tissue was believed to be just an energy-storage organ, but it is now recognized to be an active participant in energy homoeostasis and physiological functions such as immunity and inflammation. Macrophages are components of adipose tissue and actively participate in its activities. Adipose tissue is known to express and secrete a variety of products known as 'adipokines', including leptin, adiponectin, resistin and visfatin, as well as cytokines and chemokines such as tumor necrosis factor-alpha, interleukin-6 and monocyte chemoattractant protein-1. The release of adipokines by either adipocytes or adipose tissue-infiltrated macrophages leads to a chronic subinflammatory state that could play a central role in the development of insulin resistance and type 2 diabetes, and the increased risk of cardiovascular disease associated with obesity.
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Affiliation(s)
- B Antuna-Puente
- Inserm U680, faculté de médecine Saint-Antoine, université Pierre-et-Marie-Curie-Paris-6, 75012 Paris, France
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76
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Modification of the coronary artery disease risk associated with the presence of traditional risk factors by insertion/deletion polymorphism of the ACE gene. ACTA ACUST UNITED AC 2008; 11:353-9. [PMID: 18294050 DOI: 10.1089/gte.2007.0005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cigarette smoking, hypercholesterolemia, and obesity influence the renin-angiotensin system (RAS) functions including an increased synthesis of the angiotensin I converting enzyme (ACE). Thus in the present work we explore the interactions of the ACE gene insertion/deletion (I/D) polymorphism and traditional risk factors. The study cohort included 341 subjects composed of 172 patients with angiographically confirmed CAD and 169 blood donors without a history of cardiovascular diseases. The I/D polymorphism was genotyped using polymerase chain reaction (PCR) methodology. To determine the interactions between the ACE genotypes and traditional risk factors the epidemiologic approach was used (4 x 2 tables and the synergy measures). The frequency of the DD genotype was significantly higher in patients than in controls (33.7% versus 21.3%, odds ratio [OR] = 1.88, 95% CI; 1.13-3.15, p = 0.010), but greater differences were found in males (35.7% versus 20.5%, OR = 2.15, 95% CI: 1.14-4.04, p = 0.010). We found a synergy of the DD genotype with smoking (SI = 1.88, SIM = 1.22), total cholesterol > or =5 mmol/l (SI = 2.12, SIM = 1.31) and elevated low density lipoprotein (LDL) cholesterol level (> or =3 mmol/l) (SI = 1.78, SIM = 1.14). The presence of the D allele (DD + ID subjects) also increased the risk of coronary artery disease (CAD) associated with the presence of elevated total cholesterol and LDL cholesterol (SI = 1.69, SIM = 1.18, in both cases), elevated level (> or =1.7 mmol/l) of triacylglycerols (SI = 1.81, SIM = 1.18) and overweight/obesity (SI = 4.25, SIM = 2.36). In each case the estimated CAD risk was greater than that predicted by assuming the additivity of effects (the risk increased from 69% for the D allele - total cholesterol interaction to 325% for the D allele - overweight/obesity). The statistical significance was also confirmed by a multiplicative model of synergy. The DD genotype/D allele of the ACE gene increases the risk of CAD associated with the presence of traditional risk factors.
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77
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Arabpour M, Samarbafzadeh AR, Makvandi M, Shamsizadeh A, Percivalle E, Englud J, Latifi SM. THE HIGHEST PREVALENCE OF HUMAN METAPNEUMOVIRUS IN AHWAZ CHILDREN ACCOMPANIED BY ACUTE RESPIRATORY INFECTIONS. Indian J Med Microbiol 2008. [DOI: 10.1016/s0255-0857(21)01926-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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78
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Angiotensin converting enzyme inhibition from birth reduces body weight and body fat in Sprague-Dawley rats. Physiol Behav 2007; 93:820-5. [PMID: 18191966 DOI: 10.1016/j.physbeh.2007.11.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 11/28/2007] [Accepted: 11/28/2007] [Indexed: 01/01/2023]
Abstract
In vitro studies have demonstrated that angiotensin II (ANG II) induces adipocyte hyperplasia and hypertrophy. The aim of the present study was to determine the effect of angiotensin-converting enzyme inhibition on body weight, adiposity and blood pressure in Sprague-Dawley rats. From birth half of the animals (n=15) were given water to drink, while the remainder were administered perindopril in their drinking water (2 mg/kg/day). Food intake, water intake and body weight were measured weekly. Blood pressure was measured by tail cuff plethysmography at 11-weeks. Body fat content and distribution were assessed using dual energy X-ray absorptiometry and Magnetic Resonance Imaging at 12 weeks. Animals administered with perindopril had a body fat proportion that was half that of controls. This was consistent with, but disproportionately greater than the observed differences in food intake and body weight. Perindopril treatment completely removed hypertension. We conclude that the chronic inhibition of ANG II synthesis from birth specifically reduces the development of adiposity in the rat.
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79
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Antuna-Puente B, Feve B, Fellahi S, Bastard JP. [Obesity, inflammation and insulin resistance: which role for adipokines]. Therapie 2007; 62:285-92. [PMID: 17983554 DOI: 10.2515/therapie:2007055] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Adipose tissue is now recognized as an endocrine organ involved in regulating physiologic and pathologic processes including inflammation. It synthesizes and secretes hormones such as leptin and adiponectin. It can secrete other products namely adipokines including cytokines and chemokines. The release of adipokines by either adipocytes or adipose tissue-infiltrated macrophages leads to a chronic sub-inflammatory state that likely plays a major role in cardiovascular complications linked to obesity and insulin resistance.
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Affiliation(s)
- Barbara Antuna-Puente
- INSERM U680, Faculté de Médecine Saint-Antoine, Université Pierre et Marie Curie, Paris 6, Paris, France
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80
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Brücher R, Cifuentes M, Acuña MJ, Albala C, Rojas CV. Larger anti-adipogenic effect of angiotensin II on omental preadipose cells of obese humans. Obesity (Silver Spring) 2007; 15:1643-6. [PMID: 17636081 DOI: 10.1038/oby.2007.196] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The ability to form new adipose cells is important to adipose tissue physiology; however, the mechanisms controlling the recruitment of adipocyte progenitors are poorly understood. A role for locally generated angiotensin II in this process is currently proposed. Given that visceral adipose tissue reportedly expresses higher levels of angiotensinogen compared with other depots and the strong association of augmented visceral fat mass with the adverse consequences of obesity, we studied the role of angiotensin II in regulating adipogenic differentiation in omental fat of obese and non-obese humans. RESEARCH METHODS AND PROCEDURES The angiotensin II effect on adipose cell formation was evaluated in human omental adipocyte progenitor cells that were stimulated to adipogenic differentiation in vitro. The adipogenic response was measured by the activity of the differentiation marker glycerol-3-phosphate dehydrogenase. RESULTS Angiotensin II reduced the adipogenic response of adipocyte progenitor cells, and the extent of the decrease correlated directly with the subjects' BMI (p=0.01, R2=0.30). A 56.3+/-3.4% and 44.5+/-2.7% reduction of adipogenesis was found in obese and non-obese donors' cells, respectively (p<0.01). The effect of angiotensin II was reversed by type 1 angiotensin receptor antagonist losartan. DISCUSSION A greater anti-adipogenic response to angiotensin II in omental adipose progenitor cells from obese subjects opens a venue to understand the deregulation of visceral fat tissue cellularity that has been associated with severe functional abnormalities of the obese condition.
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Affiliation(s)
- Rodrigo Brücher
- Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Casilla 138-11, Santiago, Chile
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81
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Lu H, Boustany-Kari CM, Daugherty A, Cassis LA. Angiotensin II increases adipose angiotensinogen expression. Am J Physiol Endocrinol Metab 2007; 292:E1280-7. [PMID: 17213477 DOI: 10.1152/ajpendo.00277.2006] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In addition to the well-defined contribution of the liver, adipose tissue has been recognized as an important source of angiotensinogen (AGT). The purpose of this study was to define the angiotensin II (ANG II) receptors involved in regulation of adipose AGT and the relationship of this control to systemic AGT and/or angiotensin peptide concentrations. In LDL receptor-deficient (LDLR(-/-)) male mice, adipose mRNA abundance of AGT was 68% of that in liver, and adipose mRNA abundance of the angiotensin type 1a (AT(1a)) receptor (AT(1a)R) was 38% of that in liver, whereas mRNA abundance of the angiotensin type 2 (AT(2)) receptor (AT(2)R) was 57% greater in adipose tissue than in liver. AGT and angiotensin peptide concentrations were decreased in plasma of AT(1a)R-deficient (AT(1a)R(-/-)) mice and were paralleled by reductions in AGT expression in liver. In contrast, adipose AGT mRNA abundance was unaltered in AT(1a)R(-/-) mice. AT(2)R(-/-) mice exhibited elevated plasma angiotensin peptide concentrations and marked elevations in adipose AGT and AT(1a)R mRNA abundance. Increases in adipose AGT mRNA abundance in AT(2)R(-/-) mice were abolished by losartan. In contrast, liver AGT and AT(1a)R mRNA abundance were unaltered in AT(2)R(-/-) mice. Infusion of ANG II for 28 days into LDLR(-/-) mice markedly increased adipose AGT and AT(1a)R mRNA but did not alter liver AGT and AT(1a)R mRNA. These results demonstrate that differential mRNA abundance of AT(1a)/AT(2) receptors in adipose tissue vs. liver contributes to tissue-specific ANG II-mediated regulation of AGT. Chronic infusion of ANG II robustly stimulated AT(1a)R and AGT mRNA abundance in adipose tissue, suggesting that adipose tissue serves as a primary contributor to the activated systemic renin-angiotensin system.
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MESH Headings
- Adipose Tissue/metabolism
- Adipose Tissue/physiology
- Angiotensin II/biosynthesis
- Angiotensin II/genetics
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensinogen/antagonists & inhibitors
- Angiotensinogen/biosynthesis
- Angiotensinogen/genetics
- Animals
- Blotting, Western
- Gene Expression Regulation
- Liver/metabolism
- Liver/physiology
- Losartan/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/deficiency
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
- Renin-Angiotensin System/genetics
- Renin-Angiotensin System/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Hong Lu
- Cardiovascular Research Center, Gill Heart Institute, University of Kentucky, Lexington, Kentucky 4053-0200, USA
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82
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Abstract
Obesity is characterized by an expanded adipose tissue mass. Recent data suggest that adipose tissue is a multi-functional organ rather than simply a passive storage site for excess energy. It has been clearly demonstrated that human adipose tissue produces a variety of secretory factors that exert multiple effects at both the local and the systemic level. To date, >100 products, covering a broad range of protein families as well as many fatty acids and prostaglandins, have been reported to be secreted by adipose tissue. The source of these secreted factors is not only mature fat cells but also poorly-identified cells present in the stromal–vascular fraction including macrophages. Secreted factors of particular interest include many cytokines or chemokines, such as TNF-α, IL-6, IL-8, as well as plasminogen activator inhibitor-1, angiotensin-II, leptin, and adiponectin. In the obese state the expression and secretion of these factors is disturbed. With the exception of adiponectin, most circulating factors are elevated. From this perspective, obesity can be described as a pro-inflammatory condition. In addition, regional differences in adipose expression of many of these factors have been found. There is now growing evidence that many secretory factors play an important role in the pathophysiology of the metabolic and cardiovascular complications of obesity. The question arising from these observations is how the secretory pattern of adipose tissue can be modified by dietary and pharmacological measures to reduce the health risks of obesity.
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Affiliation(s)
- Hans Hauner
- Else Kröner-Fresenius-Centre for Nutritional Medicine of the Technical University of Munich, Klinikum Rechts der Isar, Germany.
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83
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López-Jaramillo P, Pradilla LP, Castillo VR, Lahera V. Patología socioeconómica como causa de las diferencias regionales en las prevalencias de síndrome metabólico e hipertensión inducida por el embarazo. Rev Esp Cardiol 2007. [DOI: 10.1157/13099463] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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84
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Engeli S, Boschmann M, Frings P, Beck L, Janke J, Titze J, Luft FC, Heer M, Jordan J. Influence of salt intake on renin-angiotensin and natriuretic peptide system genes in human adipose tissue. Hypertension 2006; 48:1103-8. [PMID: 17060507 DOI: 10.1161/01.hyp.0000248837.88749.18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We tested the hypothesis that changes in sodium intake modulate adipose-tissue renin-angiotensin and natriuretic peptide system gene expression in humans. We studied 9 healthy young men in a metabolic ward at constant room temperature, humidity, and water, potassium, and calcium intake. Subjects were submitted to 4 different periods of sodium intake, and blood samples, microdialysis samples (interstitial fluid), and biopsies from subcutaneous abdominal adipose tissue were obtained at the end of the low-sodium period (0.7 mmol Na/kg per day) and at the end of the high-sodium period (7.7 mmol Na/kg per day). Urinary sodium excretion was 64+/-4 mmol per day with the low-sodium diet and 521+/-8 mmol per day with the high-sodium diet. Systemic and microdialysate sodium concentrations were similar with both interventions. With high-sodium intake, systemic renin activity and aldosterone levels were suppressed, angiotensin-converting enzyme activity did not change, and systemic levels of the atrial natriuretic peptide increased. High-sodium diet increased angiotensin-converting enzyme and atrial natriuretic peptide gene expression in adipose tissue. None of the other genes tested were influenced by changes in dietary sodium intake. Our findings suggest that the adipose-tissue renin-angiotensin system is not part of a feedback mechanism regulating sodium homeostasis and blood pressure. Systemic and adipose-tissue renin-angiotensin systems are regulated at least in part independently from each other. In contrast, systemic atrial natriuretic peptide and adipose-tissue atrial natriuretic peptide respond similarly to changes in sodium intake.
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Affiliation(s)
- Stefan Engeli
- Franz Volhard Clinical Research Center, Medical Faculty of the Charité and Helios Klinikum, Berlin, Germany
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85
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Galili O, Versari D, Sattler KJ, Olson ML, Mannheim D, McConnell JP, Chade AR, Lerman LO, Lerman A. Early experimental obesity is associated with coronary endothelial dysfunction and oxidative stress. Am J Physiol Heart Circ Physiol 2006; 292:H904-11. [PMID: 17012356 DOI: 10.1152/ajpheart.00628.2006] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Obesity is independently associated with increased cardiovascular risk. However, since established obesity clusters with various cardiovascular risk factors, configuring the metabolic syndrome, the early effects of obesity on vascular function are still poorly understood. The current study was designed to evaluate the effect of early obesity on coronary endothelial function in a new animal model of swine obesity. As to method, juvenile domestic crossbred pigs were randomized to either high-fat/high-calorie diet (HF) or normal chow diet for 12 wk. Coronary microvascular permeability and abdominal wall fat were determined by using electron beam computerized tomography. Epicardial endothelial function and oxidative stress were measured in vitro. Systemic oxidative stress, renin-angiotensin activity, leptin levels, and parameters of insulin sensitivity were evaluated. As a result, HF pigs were characterized by abdominal obesity, hypertension, and elevated plasma lysophosphatidylcholine and leptin in the presence of increased insulin sensitivity. Coronary endothelium-dependent vasorelaxation was reduced in HF pigs and myocardial microvascular permeability increased compared with those values in normal pigs. Systemic redox status in HF pigs was similar to that in normal pigs, whereas the coronary endothelium demonstrated higher content of superoxide anions, nitrotyrosine, and NADPH-oxidase subunits, indicating increased tissue oxidative stress. In conclusion, the current study shows that early obesity is characterized by increased vascular oxidative stress and endothelial dysfunction in association with increased levels of leptin and before the development of insulin resistance and systemic oxidative stress. Vascular dysfunction is therefore an early manifestation of obesity and might contribute to the increased cardiovascular risk, independently of insulin resistance.
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Affiliation(s)
- Offer Galili
- Department of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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86
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Gudbrandsen OA, Hultstrøm M, Leh S, Monica Bivol L, Vågnes Ø, Berge RK, Iversen BM. Prevention of Hypertension and Organ Damage in 2-Kidney, 1-Clip Rats by Tetradecylthioacetic Acid. Hypertension 2006; 48:460-6. [PMID: 16847149 DOI: 10.1161/01.hyp.0000233018.60736.70] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dietary lipids are reported to affect the blood pressure in both humans and experimental animal models with hypertension. In the present study, 2-kidney, 1-clip (2K1C) hypertensive rats were treated with the modified fatty acid tetradecylthioacetic acid (TTA) from the time of clipping or after hypertension was established. TTA treatment attenuated the development of hypertension and reduced established 2K1C hypertension. The mRNA level of renin in the clipped kidney and the plasma renin activity were markedly reduced, and the plasma angiotensin II level tended to decrease after TTA treatment. In addition, TTA reduced the mRNA level of angiotensinogen in white adipose tissue. Prevention of organ damage was demonstrated by normal urinary excretion of protein, maintained serum albumin, lower heart weight, and clearly reduced vascular, glomerular, and tubulointerstitial damage in the nonclipped kidney. Renal function was not affected as estimated by unchanged plasma creatinine. Furthermore, the serum levels of triacylglycerol and cholesterol were reduced by TTA. The serum fatty acid composition was changed, resulting in a favorable increase of oleic acid. However, the levels of all of the omega-3 fatty acids and of linoleic acid were reduced, and no change was seen in the level of arachidonic acid, but the urinary excretion of 8-iso-prostaglandin F2α was declined. In conclusion, TTA attenuated the development of hypertension, reduced established hypertension, and prevented the development of organ damage in 2K1C rats, possibly by reducing the amounts of the vasoconstrictors angiotensin II and 8-iso-prostaglandin F2α and by inducing a favorable increase of oleic acid in serum.
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87
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Abstract
Since the first identification of renin by Tigerstedt and Bergmann in 1898, the renin-angiotensin system (RAS) has been extensively studied. The current view of the system is characterized by an increased complexity, as evidenced by the discovery of new functional components and pathways of the RAS. In recent years, the pathophysiological implications of the system have been the main focus of attention, and inhibitors of the RAS such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin (ANG) II receptor blockers have become important clinical tools in the treatment of cardiovascular and renal diseases such as hypertension, heart failure, and diabetic nephropathy. Nevertheless, the tissue RAS also plays an important role in mediating diverse physiological functions. These focus not only on the classical actions of ANG on the cardiovascular system, namely, the maintenance of cardiovascular homeostasis, but also on other functions. Recently, the research efforts studying these noncardiovascular effects of the RAS have intensified, and a large body of data are now available to support the existence of numerous organ-based RAS exerting diverse physiological effects. ANG II has direct effects at the cellular level and can influence, for example, cell growth and differentiation, but also may play a role as a mediator of apoptosis. These universal paracrine and autocrine actions may be important in many organ systems and can mediate important physiological stimuli. Transgenic overexpression and knock-out strategies of RAS genes in animals have also shown a central functional role of the RAS in prenatal development. Taken together, these findings may become increasingly important in the study of organ physiology but also for a fresh look at the implications of these findings for organ pathophysiology.
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Affiliation(s)
- Martin Paul
- Institute of Clinical Pharmacology and Toxicology, Campus Benjamin Franklin, Charité-University Medicine Berlin, Berlin, Germany
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88
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Affiliation(s)
- Matthew E Dickson
- Medical Scientist Training Program and Genetics Program, Carver College of Medicine, University of Iowa, Iowa City, Ia 52242, USA
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89
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Abstract
The renin-angiotensin-aldosterone system (RAAS) is a key regulator of cardiovascular function. RAAS activity is upregulated in obesity despite concurrent renal sodium retention, which is a hallmark and principle determinant of obesity-associated hypertension. The contribution of adipose tissue to increased angiotensinogen and aldosterone plasma levels in obesity is probably due to the secretion of angiotensinogen and, as yet, unidentified aldosterone secretagogues by adipocytes. Increased circulating renin activity, on the other hand, is probably due to increased sympathetic activity in the obese. Modest weight reduction significantly reduces RAAS activity by uncertain mechanisms. Pharmacological blockade of the RAAS yielded promising results, both with regard to cardiovascular function and metabolic complications of obesity. These studies suggest that the activated RAAS is a prime pharmacological target for reducing the cardiometabolic risk in obese patients.
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Affiliation(s)
- Arya M Sharma
- b Professor of Medicine, Canada Research Chair for Cardiovascular Obesity Research and Management, McMaster University, Hamilton General Hospital, 237 Barton Street East, Hamilton, ON, Canada L8L 2X2 .
| | - Stefan Engeli
- a Franz-Volhard-Zentrum für Klinische Forschung (Haus 129), Charité Campus Buch, Wiltbergstr. 50, 13125 Berlin, Germany.
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90
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Wong CY, O'Moore-Sullivan T, Leano R, Hukins C, Jenkins C, Marwick TH. Association of subclinical right ventricular dysfunction with obesity. J Am Coll Cardiol 2006; 47:611-6. [PMID: 16458145 DOI: 10.1016/j.jacc.2005.11.015] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 08/11/2005] [Accepted: 08/15/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The purpose of this research was to identify the determinants of right ventricular (RV) dysfunction in overweight and obese subjects. BACKGROUND Right ventricular dysfunction in obese subjects is usually ascribed to comorbid diseases, especially obstructive sleep apnea. We used tissue Doppler imaging to identify the determinants of RV dysfunction in overweight and obese subjects. METHODS Standard and tissue Doppler echocardiography was performed in 112 overweight (body mass index [BMI] 25 to 29.9 kg/m2) or obese (BMI >30 kg/m2) subjects and 36 referents (BMI <25 kg/m2), including 22 with obstructive sleep apnea but no obesity. Tissue Doppler was used to measure RV systolic (s(m)) and diastolic (e(m)) velocities and strain indexes. RESULTS Obese subjects with BMI >35 kg/m2 had reduced RV function compared with referent subjects, evidenced by reduced s(m) (6.5 +/- 2.4 cm/s vs. 10.2 +/- 1.5 cm/s, p < 0.001), peak strain (-21 +/- 4% vs. -28 +/- 4%, p < 0.001), peak strain rate (-1.4 +/- 0.4 s(-1) vs. -2.0 +/- 0.5 s(-1), p < 0.001), and e(m) (-6.8 +/- 2.4 cm/s vs. -10.3 +/- 2.5 cm/s, p < 0.001), irrespective of the presence of sleep apnea. Similar but lesser degrees of reduced systolic function (p < 0.05) were present in overweight (BMI 25 to 29.9 kg/m2) and mildly obese (BMI 30 to 35 kg/m2) groups. Differences in RV e(m), s(m), and strain indexes were demonstrated between the severely versus overweight and mildly obese groups (p < 0.05). Body mass index remained independently related to RV changes after adjusting for age, log insulin, and mean arterial pressures. In obese patients, these changes were associated with reduced exercise capacity but not the duration of obesity and presence of sleep apnea or its severity. CONCLUSIONS Increasing BMI is associated with increasing severity of RV dysfunction in overweight and obese subjects without overt heart disease, independent of sleep apnea.
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91
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Kusminski CM, McTernan PG, Kumar S. Role of resistin in obesity, insulin resistance and Type II diabetes. Clin Sci (Lond) 2005; 109:243-56. [PMID: 16104844 DOI: 10.1042/cs20050078] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Resistin is a member of a class of cysteine-rich proteins collectively termed resistin-like molecules. Resistin has been implicated in the pathogenesis of obesity-mediated insulin resistance and T2DM (Type II diabetes mellitus), at least in rodent models. In addition, resistin also appears to be a pro-inflammatory cytokine. Taken together, resistin, like many other adipocytokines, may possess a dual role in contributing to disease risk. However, to date there has been considerable controversy surrounding this 12.5 kDa polypeptide in understanding its physiological relevance in both human and rodent systems. Furthermore, this has led some to question whether resistin represents an important pathogenic factor in the aetiology of T2DM and cardiovascular disease. Although researchers still remain divided as to the role of resistin, this review will place available data on resistin in the context of our current knowledge of the pathogenesis of obesity-mediated diabetes, and discuss key controversies and developments.
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Affiliation(s)
- Christine M Kusminski
- Diabetes and Metabolism Research Laboratory, Clinical Sciences Research Institute, UHCW Trust, Clifford Bridge Road, Walsgrave, Coventry CV2 2DX, UK
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92
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Li Y, Jain S, Patil S, Kumar A. A haplotype of angiotensinogen gene that is associated with essential hypertension increases its promoter activity in adipocytes. Vascul Pharmacol 2005; 44:29-33. [PMID: 16303336 DOI: 10.1016/j.vph.2005.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 09/01/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
Obesity is associated with hypertension and other cardiovascular diseases especially in the African-American population. Human angiotensinogen (AGT) gene has seven single nucleotide polymorphisms (SNPs) in 1.2 kb region of its promoter. Recent studies have shown that variant -217A is associated with hypertension in African-American and Chinese population. Nucleotide sequence of the hAGT gene has shown that variant -217A almost always occurs with variants -532T, -793A and -1074T (forming haplotype AAT) and variant -217G almost always occurs with variants -532C, -793G and -1074G (forming haplotype GGG). Since hAGT gene is expressed in the adipose tissue and its expression in this tissue may play a role in hypertension, we have analyzed the role of haplotypes AAT and GGG on the expression of this gene in adipocytes. We show here that a reporter construct with haplotype AAT of the hAGT gene has increased promoter activity on transient transfection in pre-adipocytes and differentiated adipocytes as compared to the reporter construct containing GCGG haplotype. Increased expression of the AGT gene containing haplotype AAT in the liver and adipocytes may be a contributing factor for hypertension.
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Affiliation(s)
- Yanna Li
- Department of Pathology, New York Medical College, Valhalla, NY 10595, United States
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93
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Boustany CM, Brown DR, Randall DC, Cassis LA. AT1-receptor antagonism reverses the blood pressure elevation associated with diet-induced obesity. Am J Physiol Regul Integr Comp Physiol 2005; 289:R181-6. [PMID: 15774768 DOI: 10.1152/ajpregu.00507.2004] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Previous studies in our laboratory demonstrated that rats exhibiting obesity in response to a moderately high-fat (MHF) diet developed hypertension associated with activation of the local and systemic renin-angiotensin system. In this study, we examined the effect of the angiotensin type 1 (AT(1))-receptor antagonist, losartan, on blood pressure in obesity-prone (OP) and obesity-resistant (OR) rats fed a MHF diet. Using telemetry monitoring, we characterized the evolution of blood pressure elevations during the development of obesity. Male Sprague-Dawley rats were implanted with telemetry transducers for chronic monitoring of blood pressure, and baseline measurements were obtained. Rats were then switched to the MHF diet (32% kcal as fat) and were segregated into OP and OR groups at week 5. At week 9 on the MHF diet, OP rats exhibited significantly greater 24-h mean arterial blood pressure compared with OR rats (OP: 105 +/- 4 mmHg, OR: 96 +/- 2 mmHg; P < 0.05). Elevations in blood pressure in OP rats were manifest as an increase in systolic pressure. Administration of losartan to all rats at week 9 resulted in a reduction in blood pressure; however, losartan had the greatest effect in OP rats (percent decrease in mean arterial pressure by losartan; OP: 19 +/- 4, OR: 10 +/- 2%; P < 0.05). These results demonstrate that elevations in blood pressure occur subsequent to established obesity in rats fed a high-fat diet. Moreover, these results demonstrate the ability of losartan to reverse the blood pressure increase from diet-induced obesity, supporting a primary role for the renin-angiotensin system in obesity-associated hypertension.
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Affiliation(s)
- Carine M Boustany
- Division of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536-0200, USA
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94
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Hauner H. The new concept of adipose tissue function. Physiol Behav 2005; 83:653-8. [PMID: 15621071 DOI: 10.1016/j.physbeh.2004.09.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Accepted: 09/14/2004] [Indexed: 11/19/2022]
Affiliation(s)
- Hans Hauner
- Else Kröner-Fresenius-Zentrum für Ernährungsmedizin, Klinikum Rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany.
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95
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Engeli S, Böhnke J, Gorzelniak K, Janke J, Schling P, Bader M, Luft FC, Sharma AM. Weight loss and the renin-angiotensin-aldosterone system. Hypertension 2005; 45:356-62. [PMID: 15630041 DOI: 10.1161/01.hyp.0000154361.47683.d3] [Citation(s) in RCA: 442] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The renin-angiotensin-aldosterone system has been causally implicated in obesity-associated hypertension. We studied the influence of obesity and weight reduction on the circulating and adipose tissue renin-angiotensin-aldosterone system in menopausal women. Blood samples were analyzed for angiotensinogen, renin, aldosterone, angiotensin-converting enzyme activity, and angiotensin II. In adipose tissue biopsy samples, we analyzed angiotensinogen, renin, renin-receptor, angiotensin-converting enzyme, and angiotensin II type-1 receptor gene expression. Obese women (n=19) had higher circulating angiotensinogen, renin, aldosterone, and angiotensin-converting enzyme than lean women (n=19), and lower angiotensinogen gene expression in adipose tissue. Seventeen women successfully participated in a weight reduction protocol over 13 weeks to reduce daily caloric intake by 600 kcal. Body weight was reduced by -5%, as were angiotensinogen levels by -27%, renin by -43%, aldosterone by -31%, angiotensin-converting enzyme activity by -12%, and angiotensinogen expression by -20% in adipose tissue (all P<0.05). The plasma angiotensinogen decrease was highly correlated with the waist circumference decline (r=0.74; P<0.001). Weight and renin-angiotensin-aldosterone system reductions were accompanied by a -7-mm Hg reduced systolic ambulatory blood pressure. These data suggest that a 5% reduction in body weight can lead to a meaningfully reduced renin-angiotensin-aldosterone system in plasma and adipose tissue, which may contribute to the reduced blood pressure.
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Affiliation(s)
- Stefan Engeli
- Medical Faculty of the Charité, Franz Volhard Clinic and Max Delbrück Center for Molecular Medicine, HELIOS-Klinikum, Berlin, Germany.
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96
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Serazin V, Dos Santos E, Morot M, Giudicelli Y. Human adipose angiotensinogen gene expression and secretion are stimulated by cyclic AMP via increased DNA cyclic AMP responsive element binding activity. Endocrine 2004; 25:97-104. [PMID: 15711021 DOI: 10.1385/endo:25:2:097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 09/29/2004] [Accepted: 10/11/2004] [Indexed: 11/11/2022]
Abstract
Components of the adipose renin-angiotensin system (RAS) have been suggested as providing a potential path-way linking obesity to hypertension. In adipose cells, the biological responses to beta-adrenergic stimulation are mediated by an increase in intracellular cAMP. Because an association exists among body fat mass, hypertension, and increased sympathetic stimulation, we examined the influence of cAMP on angiotensinogen (ATG) expression and secretion in human adipose tissue and in parallel we studied the DNA binding activity of CRE transcriptional factors. A 24 h exposure to the cAMP analog 8Br-cAMP resulted in significant increases in ATG mRNA levels (+176+/-60%) and protein secretion (+40+/-27%). The ability of 8Br-cAMP to promote ATG gene expression was unaltered by H89, a protein kinase A inhibitor, because H89 per se was found to stimulate ATG mRNA levels and protein secretion. Moreover, 8Br-cAMP stimulated the specific CRE DNA binding activity (+115+/-14%) in human adipocyte nuclear extracts as assessed by electrophoretic mobility shift assays. These results indicate that cAMP upregulates in vitro ATG expression and secretion in human adipose tissue and that the induction in ATG mRNA levels appears to result, at least in part, from positive effects on the DNA binding activity of CRE transcription factors. Further studies are required to determine whether this regulatory pathway is activated in human obesity and to elucidate the importance of adipose ATG to the elevated blood pressure observed in this pathological state.
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Affiliation(s)
- Valérie Serazin
- Laboratoire de Biochimie et de Biologie Moléculaire de la Faculté de Médecine Paris-Ile-de-France-Ouest, UPRES EA 2493, Université Versailles Saint Quentin en Yvelines, and Hôpital de Poissy, F78303 Poissy Cedex France
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97
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Boustany CM, Bharadwaj K, Daugherty A, Brown DR, Randall DC, Cassis LA. Activation of the systemic and adipose renin-angiotensin system in rats with diet-induced obesity and hypertension. Am J Physiol Regul Integr Comp Physiol 2004; 287:R943-9. [PMID: 15191907 DOI: 10.1152/ajpregu.00265.2004] [Citation(s) in RCA: 234] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In obesity-related hypertension, activation of the renin-angiotensin system (RAS) has been reported despite marked fluid volume expansion. Adipose tissue expresses components of the RAS and is markedly expanded in obesity. This study evaluated changes in components of the adipose and systemic RAS in diet-induced obese hypertensive rats. RAS was quantified in adipose tissue and compared with primary sources for the circulating RAS. Male Sprague-Dawley rats were fed either a low-fat (LF; 11% kcal as fat) or moderately high-fat (32% kcal as fat) diet for 11 wk. After 8 wk, rats fed the moderately high-fat diet segregated into obesity-prone (OP) and obesity-resistant (OR) groups based on their body weight gain (body weight: OR, 566 ± 10; OP, 702 ± 20 g; P < 0.05). Mean arterial blood pressure was increased in OP rats (LF: 97 ± 2; OR: 97 ± 2; OP: 105 ± 1 mmHg; P < 0.05). Quantification of mRNA expression by real-time PCR demonstrated a selective increase (2-fold) in angiotensinogen gene expression in retroperitoneal adipose tissue from OP vs. OR and LF rats. Similarly, plasma angiotensinogen concentration was increased in OP rats (LF: 390 ± 48; OR: 355 ± 24; OP: 530 ± 22 ng/ml; P < 0.05). In contrast, other components of the RAS were not altered in OP rats. Marked increases in the plasma concentrations of angiotensin peptides were observed in OP rats (angiotensin II: LF: 95 ± 31; OR: 59 ± 20; OP: 295 ± 118 pg/ml; P < 0.05). These results demonstrate increased activity of the adipose and systemic RAS in obesity-related hypertension.
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Affiliation(s)
- Carine M Boustany
- Graduate Center for Nutritional Sciences, Rm. 521B, Charles T. Wethington Bldg., Univ. of Kentucky, Lexington, KY 40536-0200, USA
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98
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Yousufuddin M, Yamani MH. The renin-angiotensin hypothesis for the pathogenesis of cardiac allograft vasculopathy. Int J Cardiol 2004; 95:123-7. [PMID: 15193809 DOI: 10.1016/j.ijcard.2003.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2002] [Revised: 04/29/2003] [Accepted: 05/01/2003] [Indexed: 11/24/2022]
Abstract
The precise molecular mechanism for the development of cardiac allograft vasculopathy (CAV) after heart transplantation is not known. We, thus, hypothesize that increased activity of renin-angiotensin system (RAS) is important for the progression of CAV. There is evidence to support this concept. RAS via its principal effector molecule, angiotensin II exerts multitude of actions on vascular structure and function including regulation of vasomotor tone, cell growth/apoptosis, fibrosis and inflammation, which are particularly relevant to the genesis of atherosclerotic lesions. Risk factors, which increase predisposition to CAD, are known to activate tissue RAS and thus influence its progression. Importantly, CAD risk factors are also associated with accelerated CAV progression after transplantation. Whereas angiotensin converting enzyme (ACE) gene polymorphism increases the predisposition, pharmacological inhibition of RAS seems to reduce the incidence of CAV. These observations may support our hypothesis, provide a plausible explanation for the molecular mechanisms underlying the development of accelerated CAV and has predictions that can be tested.
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Affiliation(s)
- Mohammed Yousufuddin
- Department of Cardiovascular Medicine, Kaufman Center for Heart Failure and Transplantation, Cleveland Clinic Foundation, Cardiology, F25 9500 Euclid Avenue Cleveland, OH 44195, USA
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99
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Skurk T, Hauner H. Obesity and impaired fibrinolysis: role of adipose production of plasminogen activator inhibitor-1. Int J Obes (Lond) 2004; 28:1357-64. [PMID: 15356668 DOI: 10.1038/sj.ijo.0802778] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Obesity is the central promoter of the metabolic syndrome which also includes disturbed fibrinolysis in addition to hypertension, dyslipidaemia and impaired glucose tolerance/type 2 diabetes mellitus. Plasminogen activator inhibitor-1 (PAI-1) is the most important endogenous inhibitor of tissue plasminogen activator and uro-plasminogen activator, and is a main determinant of fibrinolytic activity. There is now compelling evidence that obesity and, in particular, an abdominal type of body fat distribution are associated with elevated PAI-1 antigen and activity levels. Recent studies established that PAI-1 is expressed in adipose tissue. The greater the fat cell size and the adipose tissue mass, the greater is the contribution of adipose production to circulating PAI-1. Experimental data show that visceral adipose tissue has a higher capacity to produce PAI-1 than subcutaneous adipose tissue. Studies in human adipocytes indicate that PAI-1 synthesis is upregulated by insulin, glucocorticoids, angiotensin II, some fatty acids and, most potently, by cytokines such as tumour necrosis factor-alpha and transforming growth factor-beta, whereas catecholamines reduce PAI-1 production. Interestingly, pharmacological agents such as thiazolidinediones, metformin and AT(1)-receptor antagonists were found to reduce adipose expression of PAI-1. In addition, weight loss by dietary restriction or comprehensive lifestyle modification is effective in lowering PAI-1 plasma levels. In conclusion, impaired fibrinolysis in obesity is probably also due to an increased expression of PAI-1 in adipose tissue. An altered function of the endocrine system and an impaired auto-/paracrine function at the fat cell levels may mediate this disturbance of the fibrinolytic system and thereby increase the risk for cardiovascular disease..
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Affiliation(s)
- T Skurk
- Else Kröner-Fresenius-Centre for Nutritional Medicine, Technical University of Munich, Freising-Weihenstephan, Germany
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100
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Prat-Larquemin L, Oppert JM, Clément K, Hainault I, Basdevant A, Guy-Grand B, Quignard-Boulangé A. Adipose angiotensinogen secretion, blood pressure, and AGT M235T polymorphism in obese patients. ACTA ACUST UNITED AC 2004; 12:556-61. [PMID: 15044674 DOI: 10.1038/oby.2004.63] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate AGT secretion in cultured adipocytes from obese patients and its relationship with obesity-related phenotypes, blood pressure, and the M235T polymorphism in the AGT gene. RESEARCH METHODS AND PROCEDURES Measurements, including anthropometry, body composition (DXA), and blood pressure, were performed in 61 overweight or obese women (BMI: 28 to 68 kg/m(2)). A subcutaneous abdominal adipose tissue biopsy was used for adipocyte size determination and quantification of AGT secretion in the medium of cultured adipocytes. AGT M235T genotype was determined using polymerase chain reaction-restriction fragment length polymorphism. RESULTS Adipose secretion of the AGT protein (range, 140 to 2575 ng/10(6) cells/24 h) was not significantly correlated with BMI, body fat, or blood pressure and did not vary according to the M235T polymorphism in the AGT gene. However, the AGT M235T polymorphism was associated with adipocyte size (111.6 +/- 2.8, 108.8 +/- 1.9, 118.2 +/- 2.6 micro m in MM, MT, and TT genotypes, respectively; p < 0.01) after adjustment for age and fat mass. An association between the AGT M235T polymorphism and adipocyte size (p < 0.02 adjusted for sex, age, and BMI) was found in another independent sample of 106 obese subjects (sex ratio, M/F 16/90; BMI, 29 to 70 kg/m(2)). DISCUSSION In cultured adipocytes from obese subjects, AGT secretion was not associated with body fat phenotypes, blood pressure, or fat cell size. However, results from two independent studies suggest an association between the AGT M235T polymorphism and adipocyte size.
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