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Aguilar BA, Vieira S, Veiga AC, da Silva JVMB, Paixao TV, Rodrigues KP, Tank J, Ruys LA, de Souza HCD. Physical exercise is essential for increasing ventricular contractility in hypertensive rats treated with losartan. Hypertens Res 2024; 47:1350-1361. [PMID: 38418900 DOI: 10.1038/s41440-024-01611-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/07/2024] [Accepted: 01/27/2024] [Indexed: 03/02/2024]
Abstract
The treatment of hypertensive patients with losartan is very common. Despite the reduction in blood pressure, its effects on cardiac contractility and sympathetic autonomic drive are still controversial. In turn, aerobic physical training (APT) also presents an important therapeutic option, providing significant improvements in cardiovascular autonomic control, however little is known about its effects on cardiac contractility, especially when associated with losartan. Therefore, we investigated in spontaneously hypertensive rats (SHR) the effects of losartan and APT on cardiac hemodynamics and functionality, with emphasis on autonomic tonic balance and cardiac contractility. Sixty-four SHR (18 weeks old) were divided into four groups (N = 16): vehicle; vehicle submitted to APT through swimming for 12 weeks; treated with losartan (5 mg·kg-1·d-1) for 12 weeks; and treated with losartan associated with APT. The groups were submitted to cardiac morphological and functional analysis by echocardiography; double blockade of cardiac autonomic receptors with atropine and propranolol; and coronary bed reactivity and left ventricular contractility analyses by the Langendorff technique. APT improved functional parameters and autonomic balance by reducing sympathetic drive and/or increasing vagal drive. In contrast, it promoted a concentric remodeling of the left ventricle (LV). Treatment with losartan reduced sympathetic autonomic drive and cardiac morphological parameters, but there were no significant gains in cardiac functionality and contractility. When combined, the concentric remodeling of the LV to APT was abolished and gains in cardiac functionality and contractility were observed. Our findings suggest that the effects of losartan and APT are complementary and should be applied together in the treatment of hypertension. In spontaneously hypertensive rats, the combination of aerobic physical training with losartan treatment was crucial to greater blood pressure reductions and an increase in left ventricular contractility. Furthermore, losartan treatment prevented the concentric left ventricular remodeling caused by aerobic physical training.
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Affiliation(s)
- Bruno Augusto Aguilar
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Suenimeire Vieira
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ana Catarine Veiga
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Tallys Velasco Paixao
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Karine Pereira Rodrigues
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jens Tank
- Department of Cardiovascular Aerospace Medicine, Institute of Aerospace Medicine, German Aerospace Center, 51147, Cologne, Germany
| | - Leticia Araujo Ruys
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Hugo Celso Dutra de Souza
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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2
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Schiffrin EL. How Structure, Mechanics, and Function of the Vasculature Contribute to Blood Pressure Elevation in Hypertension. Can J Cardiol 2020; 36:648-658. [PMID: 32389338 DOI: 10.1016/j.cjca.2020.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 01/11/2023] Open
Abstract
Large conduit arteries and the microcirculation participate in the mechanisms of elevation of blood pressure (BP). Large vessels play roles predominantly in older subjects, with stiffening progressing after middle age leading to increases in systolic BP found in most humans with aging. Systolic BP elevation and increased pulsatility penetrate deeper into the distal vasculature, leading to microcirculatory injury, remodelling, and associated endothelial dysfunction. The result is target organ damage in the heart, brain, and kidney. In younger individuals genetically predisposed to high BP, increased salt intake or other exogenous or endogenous risk factors for hypertension, including overweight and excess alcohol intake, lead to enhanced sympathetic activity and vasoconstriction. Enhanced vasoconstrictor responses and myogenic tone become persistent when embedded in an increased extracellular matrix, resulting in remodelling of resistance arteries with a narrowed lumen and increased media-lumen ratio. Stimulation of the renin-angiotensin-aldosterone and endothelin systems and inflammatory and immune activation, to which gut microbiome dysbiosis may contribute as a result of salt intake, also participate in the injury and remodelling of the microcirculation and endothelial dysfunction. Inflammation of perivascular fat and loss of anticontractile factors play roles as well in microvessel remodelling. Exaggerated myogenic tone leads to closure of terminal arterioles, collapse of capillaries and venules, functional rarefaction, and eventually to anatomic rarefaction, compromising tissue perfusion. The remodelling of the microcirculation raises resistance to flow, and accordingly raises BP in a feedback process that over years results in stiffening of conduit arteries and systo-diastolic or predominantly systolic hypertension and, more rarely, predominantly diastolic hypertension. Thus, at different stages of life and the evolution of hypertension, large vessels and the microcirculation interact to contribute to BP elevation.
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Affiliation(s)
- Ernesto L Schiffrin
- Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Québec, Canada.
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3
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Mata-Greenwood E, Blood AB, Sands LD, Bragg SL, Xiao D, Zhang L. A novel rodent model of pregnancy complications associated with genetically determined angiotensin-converting enzyme (ACE) activity. Am J Physiol Endocrinol Metab 2018; 315:E52-E62. [PMID: 29360395 PMCID: PMC6087725 DOI: 10.1152/ajpendo.00289.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Brown Norway (BN) and Lewis (LW) inbred rat strains harbor different angiotensin-converting enzyme ( Ace) polymorphisms that result in higher ACE activity in BN than LW rats. Thus we hypothesized that pregnant BN rats would show pregnancy complications linked to angiotensin II (AII) activity. We performed longitudinal and cross-sectional studies in pregnant LW and BN rats. We found that BN rats have significantly higher ACE activity and AII levels at prepregnancy and throughout pregnancy compared with LW rats, except at midgestation. BN placentas and maternal kidneys had significantly higher expression of AII receptor 1 (AGTR1) and lower expression of AGTR2 than the respective LW placentas and maternal kidneys. Renin-angiotensin system activation in BN rats correlated with hypertension and proteinuria at gestational days 17-21, which were resolved after delivery. In addition, BN rat pregnancies were characterized by significant fetal loss, restricted growth in surviving fetuses, decreased uteroplacental blood flows, and decreased trophoblast remodeling of uterine arteries compared with LW pregnancies. Short-term losartan treatment significantly increased uteroplacental blood flow and fetal weight and decreased maternal blood pressure (BP) and proteinuria in BN pregnancies. In contrast, losartan treatment significantly decreased uteroplacental blood flow and fetal weight but had no significant effect on maternal BP in LW pregnancies. We conclude that Ace polymorphisms play an important role in the reproductive phenotype of BN and LW rats and that BN rats are a novel model of pregnancy complications in association with genetically controlled, increased ACE activity.
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Affiliation(s)
- Eugenia Mata-Greenwood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University , Loma Linda, California
- Division of Pharmacology, Department of Basic Sciences, School of Medicine, Loma Linda University , Loma Linda, California
| | - Arlin B Blood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University , Loma Linda, California
- Division of Neonatology, Department of Pediatrics, School of Medicine, Loma Linda University , Loma Linda, California
| | - LeeAnna D Sands
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University , Loma Linda, California
| | - Shannon L Bragg
- Division of Neonatology, Department of Pediatrics, School of Medicine, Loma Linda University , Loma Linda, California
| | - Daliao Xiao
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University , Loma Linda, California
- Division of Pharmacology, Department of Basic Sciences, School of Medicine, Loma Linda University , Loma Linda, California
| | - Lubo Zhang
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University , Loma Linda, California
- Division of Pharmacology, Department of Basic Sciences, School of Medicine, Loma Linda University , Loma Linda, California
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4
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Dual NEP/ECE inhibition improves endothelial function in mesenteric resistance arteries of 32-week-old SHR. Hypertens Res 2017; 40:738-745. [DOI: 10.1038/hr.2017.38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/22/2016] [Accepted: 01/23/2017] [Indexed: 01/06/2023]
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5
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Physical training associated with Enalapril but not to Losartan, results in better cardiovascular autonomic effects. Auton Neurosci 2017; 203:33-40. [DOI: 10.1016/j.autneu.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 12/04/2016] [Accepted: 12/06/2016] [Indexed: 01/13/2023]
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Virdis A, Gesi M, Taddei S. Impact of apocynin on vascular disease in hypertension. Vascul Pharmacol 2016; 87:1-5. [PMID: 27569106 DOI: 10.1016/j.vph.2016.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 07/25/2016] [Accepted: 08/20/2016] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) are generated by cell metabolism of oxygen and represent signaling molecules playing an active role in vascular biology. In pathological conditions, including hypertension, a ROS excess, together with reduced endogenous antioxidant defenses, occurs, determining a state of oxidative stress. NAD(P)H oxidase (Nox) is a major ROS source within the vasculature. A large body of literature has demonstrated that hypertension-associated vascular functional and structural changes are attributable to Nox-driven intravascular ROS generation. Apocynin is a methoxy-catechol discovered as an inhibitor of superoxide. It has been utilized in several laboratories and in different models of hypertension as an inhibitor of Nox. Recent evidence proposes that apocynin predominantly acts as an antioxidant. The present review will discuss the role of ROS in vascular disease in hypertension and the impact of apocynin on these vascular changes.
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Affiliation(s)
- Agostino Virdis
- Department of Clinical and Experimental Medicine, University of Pisa, Italy.
| | - Marco Gesi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Italy
| | - Stefano Taddei
- Department of Clinical and Experimental Medicine, University of Pisa, Italy
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Bachhav SS, Bhutada MS, Patil SP, Sharma KS, Patil SD. Oleanolic Acid Prevents Increase in Blood Pressure and Nephrotoxicity in Nitric Oxide Dependent Type of Hypertension in Rats. Pharmacognosy Res 2015; 7:385-92. [PMID: 26692754 PMCID: PMC4660519 DOI: 10.4103/0974-8490.159575] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Background: Recently, we have reported antihypertensive activity of oleanolic acid (OA) in glucocorticoid-induced hypertension with restoration of nitric oxide (NO) level. However, the involvement of NO-releasing action of OA was unclear. Objective: To explore antihypertensive activity of OA in Nω-nitro-L-arginine methyl ester (L-NAME) hypertensive rats wherein NO is completely blocked, which would allow exploring the possibility of involvement of NO-releasing action of OA. Materials and Methods: Five groups of rats were investigated as normal control, L-NAME (40 mg/kg/day), L-NAME + enalapril (15 mg/kg/day), L-NAME + l-arginine (100 mg/kg/day), and L-NAME + OA (60 mg/kg/day) for 4 weeks. The systolic blood pressure, body weight, and heart rate were measured weekly for 4 weeks. Serum nitrate/nitrite (NOx) level, urine electrolytes concentration, cardiac mass index, and serum creatinine level were determined followed by organ histopathology. Results: OA and enalapril delayed the rise in blood pleasure following L-NAME administration. Decreased serum NOx level was not significantly increased with any of the treatment. OA produced a small, though nonsignificant, increase in the NOx level. L-NAME administration did not affect cardiac mass index. There was an increase in serum creatinine upon L-NAME administration which was prevented by OA. Decreased urine volume, urine sodium and potassium were reversed by OA. Conclusion: These results suggest that the antihypertensive effect of OA in L-NAME hypertension is due to diuresis and nephroprotection. However, OA has nonsignificantly affected the NO levels.
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Affiliation(s)
- Sagar S Bachhav
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dhule, Maharashtra, India
| | - Mukesh S Bhutada
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dhule, Maharashtra, India
| | - Sachin P Patil
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dhule, Maharashtra, India
| | - Kinjal S Sharma
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dhule, Maharashtra, India
| | - Savita D Patil
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dhule, Maharashtra, India
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Novel players in cardioprotection: Insulin like growth factor-1, angiotensin-(1–7) and angiotensin-(1–9). Pharmacol Res 2015; 101:41-55. [DOI: 10.1016/j.phrs.2015.06.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 06/27/2015] [Accepted: 06/28/2015] [Indexed: 12/14/2022]
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Mendoza-Torres E, Oyarzún A, Mondaca-Ruff D, Azocar A, Castro PF, Jalil JE, Chiong M, Lavandero S, Ocaranza MP. ACE2 and vasoactive peptides: novel players in cardiovascular/renal remodeling and hypertension. Ther Adv Cardiovasc Dis 2015; 9:217-37. [PMID: 26275770 DOI: 10.1177/1753944715597623] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The renin-angiotensin system (RAS) is a key component of cardiovascular physiology and homeostasis due to its influence on the regulation of electrolyte balance, blood pressure, vascular tone and cardiovascular remodeling. Deregulation of this system contributes significantly to the pathophysiology of cardiovascular and renal diseases. Numerous studies have generated new perspectives about a noncanonical and protective RAS pathway that counteracts the proliferative and hypertensive effects of the classical angiotensin-converting enzyme (ACE)/angiotensin (Ang) II/angiotensin type 1 receptor (AT1R) axis. The key components of this pathway are ACE2 and its products, Ang-(1-7) and Ang-(1-9). These two vasoactive peptides act through the Mas receptor (MasR) and AT2R, respectively. The ACE2/Ang-(1-7)/MasR and ACE2/Ang-(1-9)/AT2R axes have opposite effects to those of the ACE/Ang II/AT1R axis, such as decreased proliferation and cardiovascular remodeling, increased production of nitric oxide and vasodilation. A novel peptide from the noncanonical pathway, alamandine, was recently identified in rats, mice and humans. This heptapeptide is generated by catalytic action of ACE2 on Ang A or through a decarboxylation reaction on Ang-(1-7). Alamandine produces the same effects as Ang-(1-7), such as vasodilation and prevention of fibrosis, by interacting with Mas-related GPCR, member D (MrgD). In this article, we review the key roles of ACE2 and the vasoactive peptides Ang-(1-7), Ang-(1-9) and alamandine as counter-regulators of the ACE-Ang II axis as well as the biological properties that allow them to regulate blood pressure and cardiovascular and renal remodeling.
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Affiliation(s)
- Evelyn Mendoza-Torres
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Alejandra Oyarzún
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - David Mondaca-Ruff
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Andrés Azocar
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Pablo F Castro
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile Division Enfermedades Cardiovasculares, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge E Jalil
- Division Enfermedades Cardiovasculares, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mario Chiong
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - María Paz Ocaranza
- Advanced Center for Chronic Diseases(ACCDiS), Facultad de Medicina, PontificiaUniversidad Católica de Chile, Santiago, Chile.Division Enfermedades Cardiovasculares,Facultad de Medicina, Pontificia UniversidadCatólica de Chile, Santiago, Chile
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10
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Azu OO. Testicular morphology in spontaneously hypertensive rat model: oxidant status and stereological implications. Andrologia 2014; 47:123-37. [PMID: 24471984 DOI: 10.1111/and.12233] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2013] [Indexed: 12/21/2022] Open
Abstract
Studies by researchers suggest that reductions in blood flow to the testis could play an important role in the pathogenesis of male infertility. As this oxygen-dependent organ functions in a state of near anoxia, such a decrease in blood flow may very likely have profound effects on the tissue morphology that ultimately would predispose to various forms of hypo-spermatogenesis with consequent compromise in reproductive capability. With varying opinions expressed by experts as to the actual culprit or potential pathway and/or effects of pathophysiology of testicular haemodynamics, it still remains debatable whether the observed degenerative changes in testicular tissue are the result of major or minor reductions in flow or the consequence of other vascular pathologies or even extraneous factors. Again, increasing age and male gender have been identified as the single independent risk factors for the occurrence of cardiovascular pathologies with sexual dimorphism highly debated. The investigation of these factors occurring under hypertensive states using the spontaneously hypertensive rat (SHR) as an experimental model has attracted substantial attention in recent past. This review examines the relationships and potential morphologic changes in the testicular tissue under conditions of perturbations in blood flow as seen in the SHR with a view to the proper understanding of the role(s) of various factors that contributes to male subfertility. A suggestion to the use of stereological methods for quantitating various measurements in a highly active and dynamic structure like the testis with its arterial system has been added as this may facilitate a better understanding of the mechanisms implicated under hypertensive conditions.
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Affiliation(s)
- O O Azu
- Discipline of Clinical Anatomy, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
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Shouk R, Abdou A, Shetty K, Sarkar D, Eid AH. Mechanisms underlying the antihypertensive effects of garlic bioactives. Nutr Res 2014; 34:106-15. [PMID: 24461311 DOI: 10.1016/j.nutres.2013.12.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 12/25/2013] [Accepted: 12/26/2013] [Indexed: 01/12/2023]
Abstract
Cardiovascular disease remains the leading cause of death worldwide with hypertension being a major contributing factor to cardiovascular disease-associated mortality. On a population level, non-pharmacological approaches, such as alternative/complementary medicine, including phytochemicals, have the potential to ameliorate cardiovascular risk factors, including high blood pressure. Several epidemiological studies suggest an antihypertensive effect of garlic (Allium sativum) and of many its bioactive components. The aim of this review is to present an in-depth discussion regarding the molecular, biochemical and cellular rationale underlying the antihypertensive properties of garlic and its bioactive constituents with a primary focus on S-allyl cysteine and allicin. Key studies, largely from PubMed, were selected and screened to develop a comprehensive understanding of the specific role of garlic and its bioactive constituents in the management of hypertension. We also reviewed recent advances focusing on the role of garlic bioactives, S-allyl cysteine and allicin, in modulating various parameters implicated in the pathogenesis of hypertension. These parameters include oxidative stress, nitric oxide bioavailability, hydrogen sulfide production, angiotensin converting enzyme activity, expression of nuclear factor-κB and the proliferation of vascular smooth muscle cells. This review suggests that garlic and garlic derived bioactives have significant medicinal properties with the potential for ameliorating hypertension and associated morbidity; however, further clinical and epidemiological studies are required to determine completely the specific physiological and biochemical mechanisms involved in disease prevention and management.
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Affiliation(s)
- Reem Shouk
- Department of Biology, Faculty of Science, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Aya Abdou
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Kalidas Shetty
- Department of Plant Sciences, North Dakota State University, Fargo, USA
| | - Dipayan Sarkar
- Department of Plant Sciences, North Dakota State University, Fargo, USA
| | - Ali H Eid
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar.
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Khavandi K, Arunakirinathan M, Greenstein AS, Heagerty AM. Retinal arterial hypertrophy: the new LVH? Curr Hypertens Rep 2013; 15:244-52. [PMID: 23575736 DOI: 10.1007/s11906-013-0347-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Prevention of target organ damage represents the El Dorado for clinicians who treat hypertension. Although many of the cardiovascular sequelae of chronic hypertension are due to large artery atherosclerosis, an equal number are due to small artery dysfunction. These microvascular complications include eye disease (retinopathy), kidney failure, diastolic dysfunction of the heart and small vessel brain disease leading to stroke syndromes, dementia and even depression. Examination of the retinal vasculature represents the only way to reliably derive information regarding small arteries responsible for these diverse pathologies. This review aims to summarise the rapidly accruing evidence indicating that easily observable abnormalities of retinal arteries reflect target organ damage elsewhere in the body of hypertensive patients. In tandem, we also present putative mechanisms by which hypertension and diabetes fundamentally change small artery structure and function and how these processes may lead to target organ damage.
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Affiliation(s)
- Kaivan Khavandi
- British Heart Foundation Centre of Excellence, Department of Cardiology, St. Thomas' Hospital, King's College London, London, UK.
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13
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Vélez JM, Chamorro GA, Calzada CC, Zuñiga CA, Vélez JJ, Ocharán E. A study of prevention and regression of cardiac hypertrophy with a prolactin inhibitor in a biological model of ventricular hypertrophy caused by aorto caval fistulae in rat. Cardiovasc Pathol 2013; 22:357-67. [PMID: 23478013 DOI: 10.1016/j.carpath.2013.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 01/11/2013] [Accepted: 01/11/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The possibility of decreasing or reverting left ventricular hypertrophy and, therefore, cardiac hypertrophy (CH) is an important medical issue. The aim of the present study was to evaluate these two possibilities with a 3-week daily dose of captopril, losartan, or bromocriptine in a preventive or corrective model. METHODS After aorto caval fistulae (ACF) surgery on adult male Wistar rats to induce CH, animals were assigned to the preventive protocol (drug treatment began immediately after surgery) or corrective protocol (hypertrophy was allowed to develop before drug treatment). After treatments, isoproterenol was administered to half of the animals to further induce CH. The groups included the passive control, the sham-operated animals, those with ACF surgery but without drug treatment, and the 3-week treatments with captopril, losartan, or the low or high dose of bromocriptine. RESULTS Three treatments, with captopril, losartan, or the high dose of bromocriptine, significantly impeded/reverted an increase in CH-related parameters in the preventive/corrective model compared to the surgically treated group without drug treatment. The same effect was found after isoproterenol administration. The present results show an avoidance/reversion of CH with these three treatments. Better results were found with the angiotensin converting enzyme inhibitor (captopril) than with the prolactin inhibitor (bromocriptine). CONCLUSIONS Treatments with captopril, losartan, and the high dose of bromocriptine were effective in preventing/reversing the manifestation of CH in the preventive/corrective rat models. Further studies are needed to identify the initial mediator, the key component, and the molecular events involved in the pathogenesis of CH.
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Affiliation(s)
- Juan M Vélez
- Intracellular Signaling Laboratory, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, México
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Cha JH, Lee HR, Kim KC, Cho MS, Hong YM. Changes of gene expressions in spontaneously hypertensive rat model after losartan treatment. Korean Circ J 2012; 42:761-8. [PMID: 23236328 PMCID: PMC3518710 DOI: 10.4070/kcj.2012.42.11.761] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 03/31/2012] [Accepted: 06/04/2012] [Indexed: 11/12/2022] Open
Abstract
Background and Objectives The renin angiotensin system seems to play an important role in the development of cardiac and vascular hypertrophy in hypertension. The changes in pathology, and gene expressions of the angiotensin II receptor type 1A (ATIA) and angiotensin converting enzyme (ACE) were investigated in order to explore the effects of losartan in spontaneously hypertensive rat (SHR) models. Materials and Methods Twelve week-old male Wistar rats were grouped as follows: control (C) group, hypertension (H) group, and losartan (L) group in which SHR was treated with losartan (10 mg/kg/day). Western blot and reverse transcription-polymerase chain reaction analysis regarding seven genes such as endothelin-1, ACE, ATIA, neutrophil cytosolic factor, brain natriuretic peptide, troponin I, endothelial nitric oxide synthase were performed. Results Systolic blood pressure was significantly decreased in the L group compared with the H group in weeks 3 and 5. ACE and ATIA proteins in the L group were lower than H group in week 5. Conclusion Losartan reduced blood pressure, cardiac hypertrophy and protein expressions of ACE and ATIA. Changes of protein expressions were more sensitive than changes in pathology. Further study is needed for the differing doses of losartan in SHR models.
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Affiliation(s)
- Ji Hei Cha
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea
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Dual neural peptidase/endothelin-converting enzyme inhibition improves endothelial function in mesenteric resistance arteries of young spontaneously hypertensive rats. J Hypertens 2012; 30:1799-808. [DOI: 10.1097/hjh.0b013e3283569c7a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bachhav SS, Bhutada MS, Patil SD, Baser B, Chaudhari KB. Effect of Viscum articulatum Burm. (Loranthaceae) in Nω-nitro-L-arginine methyl ester induced hypertension and renal dysfunction. JOURNAL OF ETHNOPHARMACOLOGY 2012; 142:467-473. [PMID: 22626924 DOI: 10.1016/j.jep.2012.05.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 05/01/2012] [Accepted: 05/12/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Viscum articulatum Burm. is used traditionally in Chinese medicine for treating hypertension. AIM OF THE STUDY The present study was designed to evaluate the antihypertensive activity of the methanolic extract of Viscum articulatum (MVA) against N(ω)-nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. MATERIALS AND METHODS Six groups of rats were investigated for 4 weeks as normal control, L-NAME (40 mg/kg/day), L-NAME+enalapril (15 mg/kg/day), L-NAME+L-arginine (100 mg/kg/day), L-NAME+MVA (200 mg/kg/day) and L-NAME+MVA (400 mg/kg/day) for four weeks. The systolic blood pressure (SBP) and heart rate (HR) were measured weekly throughout the experimental period. The urine electrolytes concentration, cardiac mass index, serum nitrate/nitrite (NO(x)) level, serum creatinine level and lipid profile were determined. RESULTS Treatment with MVA (200 and 400 mg/kg) or enalapril delayed the rise in SBP produced by administration of L-NAME. None of the treatments had a significant effect on the depression of the serum NO(x) level caused by L-NAME. The serum creatinine and total cholesterol concentrations were elevated upon administration of L-NAME, and this elevation was prevented by MVA co-administration. The urine volume and urine potassium ion level were depressed by L-NAME administration and this effect being inhibited in MVA and enalapril groups. There was no cardiac hypertrophy and HR change after 28 day of L-NAME administration. CONCLUSION We conclude that MVA may have an antihypertensive effect in the NO deficient type of hypertension, which may be attributed to its diuretic, nephroprotective and hypolipidemic actions.
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Affiliation(s)
- Sagar S Bachhav
- Department of Pharmacology, R.C. Patel Institute of Pharmaceutical Education and Research, Near Karwand Naka, Shirpur, District Dhule 425 405, Maharashtra, India
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Impaired flow-induced arterial remodeling in DOCA-salt hypertensive rats. Hypertens Res 2012; 35:1093-101. [DOI: 10.1038/hr.2012.94] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nishida Y, Tandai-Hiruma M, Kemuriyama T, Hagisawa K. Long-term blood pressure control: is there a set-point in the brain? J Physiol Sci 2012; 62:147-61. [PMID: 22302247 PMCID: PMC10717488 DOI: 10.1007/s12576-012-0192-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 01/11/2023]
Abstract
Mean arterial pressure fluctuates depending on physical or psychological activity, but should be stable at rest at around 100 mmHg throughout an entire life in human. The causes of hypertension and the blood pressure regulation mechanisms have been discussed for a long time, and many aspects have recently become more clear. Circulatory shock or short-term hypotension can be treated based on what is now known, but chronic hypertension is still difficult to treat thoroughly. The exact mechanisms for long-term blood pressure regulation have yet not been elucidated. Neuro–humoral interaction has been suggested as one of the mechanisms. Then, from the 1990s, paracrine hormones like nitric oxide or endothelins have been extensively researched in order to develop endothelial local control mechanisms for blood pressure, which have some relationships to long-term control. Although these new ideas and mechanisms are newly developed, no clear explanation for long-term control has yet been discussed, except for renal abnormality. Recently, a central set-point theory has begun to be discussed. This review will discuss the mechanisms for long-term blood pressure control, based on putative biological missions of circulatory function for life support.
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Affiliation(s)
- Yasuhiro Nishida
- Department of Physiology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan.
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Protective Role of the ACE2/Ang-(1-9) Axis in Cardiovascular Remodeling. Int J Hypertens 2012; 2012:594361. [PMID: 22315665 PMCID: PMC3270559 DOI: 10.1155/2012/594361] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/05/2011] [Accepted: 10/09/2011] [Indexed: 12/21/2022] Open
Abstract
Despite reduction in cardiovascular (CV) events and end-organ damage with the current pharmacologic strategies, CV disease remains the primary cause of death in the world. Pharmacological therapies based on the renin angiotensin system (RAS) blockade are used extensively for the treatment of hypertension, heart failure, and CV remodeling but in spite of their success the prevalence of end-organ damage and residual risk remain still high. Novel approaches must be discovered for a more effective treatment of residual CV remodeling and risk. The ACE2/Ang-(1–9) axis is a new and important target to counterbalance the vasoconstrictive/proliferative RAS axis. Ang-(1–9) is hydrolyzed slower than Ang-(1–7) and is able to bind the Ang II type 2 receptor. We review here the current experimental evidence suggesting that activation of the ACE2/Ang-(1–9) axis protects the heart and vessels (and possibly the kidney) from adverse cardiovascular remodeling in hypertension as well as in heart failure.
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Ivanov M, Mihailovic-Stanojevic N, Grujic Milanovic J, Jovovic D, Miloradovic Z. Prevention of systemic and regional haemodynamic alterations, hypercreatininemia, hyperuremia and hyperphosphatemia by losartan in hypertension with acute renal failure. ACTA ACUST UNITED AC 2011; 98:1-7. [DOI: 10.1556/aphysiol.98.2011.1.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Resveratrol and small artery compliance and remodeling in the spontaneously hypertensive rat. Am J Hypertens 2010; 23:1273-8. [PMID: 20671721 DOI: 10.1038/ajh.2010.161] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Small arteries from the spontaneously hypertensive rat (SHR) exhibit abnormal stiffness and geometry. This study investigated the effects of resveratrol, a polyphenol found in foods such as red grapes, on small arteries in SHR. METHODS Wistar-Kyoto (WKY) rats and SHR were treated with resveratrol (2.5 mg/kg/day) for 10 weeks. Mesenteric small artery segments (third-order branches) were mounted in a pressure myograph, and vascular geometry and mechanical properties were calculated from lumen and media dimensions measured at incremental intraluminal pressures. Systolic blood pressure was measured by tail-cuff plethysmography. RESULTS Increased compliance and reduced wall component stiffness were observed in SHR arteries vs. WKY arteries. Though resveratrol did not prevent lowering of wall component stiffness, it did attenuate, at least in part, the increased compliance of SHR arteries. In contrast, resveratrol increased compliance and reduced wall component stiffness in WKY arteries. SHR arteries exhibited remodeling that consisted of narrowed lumens, thickened media widths, and augmented media-to-lumen ratios. Resveratrol partially attenuated the remodeling process and also abolished exaggerated ERK signaling and expression of proliferating cell nuclear antigen (a marker of proliferation) in SHR arteries. The latter effects might be related to the ability of resveratrol to alleviate oxidative stress in SHR and enhance protein kinase G (PKG) activity. Elevated blood pressure in 20-week-old SHR was unaffected by resveratrol. CONCLUSIONS The ability of resveratrol to limit the increase in compliance of SHR arteries is likely related to inhibitory effects on remodeling and pro-growth ERK signaling rather than blood pressure or arterial wall component stiffness.
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Porteri E, Rodella L, Rizzoni D, Rezzani R, Paiardi S, Sleiman I, De Ciuceis C, Boari GEM, Castellano M, Bianchi R, Agabiti-Rosei E. Effects of olmesartan and enalapril at low or high doses on cardiac, renal and vascular interstitial matrix in spontaneously hypertensive rats. Blood Press 2009; 14:184-92. [PMID: 16036499 DOI: 10.1080/08037050510034211] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We have evaluated the effects of different doses of an angiotensin-converting enzyme (ACE) inhibitor, enalapril (ENA) and of an angiotensin II type 1 receptor blocker olmesartan (OLM), on extracellular matrix of the heart, kidney, aorta and mesenteric artery of spontaneously hypertensive rats (SHR). Forty SHR and eight Wistar-Kyoto controls (WKY) were included in the study. Eight SHR were treated with high-dose OLM 15 mg/kg per day, eight with high-dose ENA 25 mg/kg per day, eight with low-dose OLM 1 mg/kg per day and eight with low-dose ENA (2 mg/kg per day). Eight SHR and eight WKY were kept untreated as controls. Treatment was from age 4 to 12 weeks. Systolic blood pressure (SBP) was measured non-invasively every week. The left ventricular weight to body weight (RLVM) was measured, and the cardiac, aortic and glomerular interstitial collagen content was evaluated using Sirius red staining and image analysis. Mesenteric small arteries were dissected and mounted on a micromyograph, and the media:lumen ratio (M/L) was calculated. Collagen subtypes were evaluated by polarized light microscopy. The SHR treated with high-dose OLM or ENA showed a normalization of SBP. The RLVM was significantly increased in untreated SHR compared with untreated WKY, whereas significantly lower values were observed in the groups of SHR treated with high-dose OLM or ENA. A significant increase in cardiac and glomerular collagen content was observed in untreated SHR. Both high- or low-dose OLM and ENA normalized collagen content in the heart and the kidney. Both high-dose OLM and high-dose ENA normalized M/L ratio; however, OLM proved to be more effective than ENA in normalizing collagen pattern. In fact, aortic collagen content was normalized by both high-dose and low-dose OLM, but only by high-dose ENA. In conclusion, both OLM and ENA were significantly and equally effective in the prevention of cardiac and renal damage in SHR, whereas OLM was more effective than ENA in terms of effects on vascular extracellular matrix.
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Affiliation(s)
- Enzo Porteri
- Department of Medical and Surgical Sciences, University of Brescia, Italy
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Rizzoni D, Castellano M, Porteri E, Giacchè M, Ferrari P, Cusi D, De Ciuceis C, Boari GEM, Rosei EA. Functional alterations of mesenteric small resistance arteries in Milan hypertensive and normotensive rats. Hypertens Res 2009; 32:581-5. [PMID: 19407819 DOI: 10.1038/hr.2009.57] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Milan hypertensive rat strain (MHS) is a genetic strain in which cardiovascular phenotypes seem to be dependent, at least in part, on adducin gene polymorphisms. The aim of our study was to evaluate the structure, contractile responses and endothelium-dependent vasodilation in mesenteric small resistance arteries in 12-week-old MHS, (n=7), age-matched Milan normotensive rats (MNS, n=7) and congenic strains in which the DNA segments carrying the alpha-adducin locus from the MHS have been introgressed into the MNS (MNA, n=7). Systolic blood pressure (tail cuff) and left ventricular weight to body weight were measured. Mesenteric small arteries were dissected and mounted on a micromyograph; the media:lumen ratio was then calculated. Concentration-response curves to acetylcholine and to norepinephrine (NE) were created. Systolic blood pressure was significantly increased in the MHS and MNA strains compared with the MNS. No significant difference in mesenteric small resistance artery structure was observed among the groups; however, a slightly more elevated media:lumen ratio was observed in MNA compared with the MNS. In contrast, left ventricular weight to body weight was significantly increased and ACH-induced dilatation was significantly impaired in the MHS and in MNA compared with MNS. The concentration-response curve to NE in the MHS showed significantly reduced sensitivity to NE; however, maximum contraction was increased in the MHS vs. the other groups. The MHS presents cardiac (but not vascular) remodeling, endothelial dysfunction and a peculiar contractile response to NE, compared with the other groups. The systolic blood pressure increase and trend to vascular remodeling in MNA support the pathogenic role of alpha-adducin.
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Affiliation(s)
- Damiano Rizzoni
- Department of Medical and Surgical Sciences, University of Brescia, Clinica Medica, Brescia, Italy.
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Martinez-Lemus LA, Hill MA, Meininger GA. The plastic nature of the vascular wall: a continuum of remodeling events contributing to control of arteriolar diameter and structure. Physiology (Bethesda) 2009; 24:45-57. [PMID: 19196651 DOI: 10.1152/physiol.00029.2008] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The diameter of resistance arteries has a profound effect on the distribution of microvascular blood flow and the control of systemic blood pressure. Here, we review mechanisms that contribute to the regulation of resistance artery diameter, both acutely and chronically, their temporal characteristics, and their interdependence. Furthermore, we hypothesize the existence of a remodeling continuum that allows for the vascular wall to rapidly modify its structural characteristics, specifically through the re-positioning of vascular smooth muscle cells. Importantly, the concepts presented more closely link acute vasoregulatory responses with adaptive changes in vessel wall structure. These rapid structural adaptations provide resistance vessels the ability to maintain a desired diameter under presumed optimal energetic and mechanical conditions.
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Affiliation(s)
- Luis A Martinez-Lemus
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, Missouri, USA
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Sonoyama K, Greenstein A, Price A, Khavandi K, Heagerty T. Vascular remodeling: implications for small artery function and target organ damage. Ther Adv Cardiovasc Dis 2009; 1:129-37. [PMID: 19124402 DOI: 10.1177/1753944707086358] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
At the level of the small artery, essential hypertension is associated with eutrophic inward remodeling. This involves reduction in lumen diameter by an increase in wall thickness. Previously thought to involve either hypertrophy or hyperplasia of the vascular smooth muscle cells in the media, it is now felt to be mediated by a functional property of the wall: myogenic tone. This is the ability of an artery to contract in response to an increase in intraluminal pressure. This autoregulatory function is also vital to ensure stabilisation of distal capillary pressures and so prevent, or limit, organ damage. Indeed in any animal model studied, when myogenic autoregulation is affected, target organ damage ensues. We have also observed, in two studies, that when myogenic autoregulation is damaged in the context of hypertension, eutrophic remodeling is replaced by an outward growth of the arterial wall with preservation of lumen diameter. This is called hypertrophic remodeling and, independently, has been observed by a number of groups in small arteries from patients with type 2 diabetes. We believe that this is a key reason for the unique propensity to hypertensive injury seen in patients with diabetes. We also discuss the significance of integrins, transmembrane proteins with wide ranging functions; from initiation of cell migration to intracellular signalling. Two particular integrins, alpha5beta1 and alphanubeta3, have been found to be necessary for both normal myogenic autoregulation and eutrophic remodeling and the possibility that damage to these may occur in diabetes is examined.
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Affiliation(s)
- Kazuhiko Sonoyama
- Division of Cardiovascular and Endocrine Sciences, University of Manchester, UK
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26
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Komatsu H, Yamada S, Iwano H, Okada M, Onozuka H, Mikami T, Yokoyama S, Inoue M, Kaga S, Nishida M, Shimizu C, Matsuno K, Tsutsui H. Angiotensin II Receptor Blocker, Valsartan, Increases Myocardial Blood Volume and Regresses Hypertrophy in Hypertensive Patients. Circ J 2009; 73:2098-103. [DOI: 10.1253/circj.cj-09-0324] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hiroshi Komatsu
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | - Satoshi Yamada
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | - Hiroyuki Iwano
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | - Masako Okada
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | | | | | - Shinobu Yokoyama
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Mamiko Inoue
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Sanae Kaga
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Mutsumi Nishida
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Chikara Shimizu
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Kazuhiko Matsuno
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital
| | - Hiroyuki Tsutsui
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
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Khavandi K, Greenstein AS, Sonoyama K, Withers S, Price A, Malik RA, Heagerty AM. Myogenic tone and small artery remodelling: insight into diabetic nephropathy. Nephrol Dial Transplant 2008; 24:361-9. [DOI: 10.1093/ndt/gfn583] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Smith RD, Yokoyama H, Averill DB, Schiffrin EL, Ferrario CM. Reversal of vascular hypertrophy in hypertensive patients through blockade of angiotensin II receptors. ACTA ACUST UNITED AC 2008; 2:165-72. [DOI: 10.1016/j.jash.2007.11.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 11/08/2007] [Accepted: 11/08/2007] [Indexed: 11/25/2022]
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Angiotensin II Signaling in Vascular Physiology and Pathophysiology. SIGNAL TRANSDUCTION IN THE CARDIOVASCULAR SYSTEM IN HEALTH AND DISEASE 2008. [PMCID: PMC7121295 DOI: 10.1007/978-0-387-09552-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Initially recognized as a physiologic regulator of blood pressure and body fluid homeostasis, angiotensin (Ang) II has now been shown in innumerable experiments and clinical studies to contribute to the development and maintenance of cardiovascular disease. Dissection of its signaling mechanisms over the past decades has led to the discovery of several novel concepts, such as tissue-specific metabolism of Ang peptides. Identification and cloning of the various receptors through which Ang II acts on almost all tissues has led to the development of specific pharmacologic inhibitors with proven clinical benefit in patients with cardiovascular disorders. Work on the G-protein-coupled Ang II Type 1 receptor has demonstrated that different receptors interact through oligomerization, compartmentalization, and transactivation, and may explain how Ang II can activate G-protein-independent pathways. Unraveling the downstream effects of Ang II in specific cell types corroborates the importance of the cellular redox state on certain signaling pathways. Finally, the effects of Ang II on cell function and phenotype, such as the expression of inflammatory cytokines and receptors promoting the recruitment of inflammatory cells into vascular tissues, have indicated its role in local inflammation as a general pathogenetic basis of cardiovascular disease. The recognition of Ang II as a contributor to such fundamental pathophysiologic mechanisms, which are believed to be a common pathway for diverse cardiovascular risk factors like hypertension and diabetes, has greatly advanced our knowledge of pathologic signaling in vascular tissues and may help to eventually define novel targets for pharmacologic interventions.
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Carey RM. Pathophysiology of Primary Hypertension. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00020-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Calcitonin Gene-Related Peptide-Mediated Depressor Effect and Inhibiting Vascular Hypertrophy of Rutaecarpine in Renovascular Hypertensive Rats. J Cardiovasc Pharmacol 2007; 50:654-9. [DOI: 10.1097/fjc.0b013e3181579e7e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ikeda F, Azuma K, Ogihara T, Toyofuku Y, Otsuka A, Mita T, Hirose T, Tanaka Y, Kawamori R, Watada H. Angiotensin II type 1 receptor blocker reduces monocyte adhesion to endothelial cells in spontaneously hypertensive rats. Endocr J 2007; 54:605-12. [PMID: 17641443 DOI: 10.1507/endocrj.k07-004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Monocyte adhesion to arterial endothelial cells is the initial step in atherosclerosis. Whereas angiotensin II is known to elicit leukocyte adhesion, it is not clear whether blockade of the angiotensin II receptor signaling reduces monocyte adhesion to endothelial cells beyond its antihypertensive action. This study compared the effect of two different antihypertensive drugs on monocyte adhesion to thoracic aorta endothelium in spontaneously hypertensive rats (SHR): the angiotensin II receptor blocker, valsartan (20 mg . kg(-1) . day(-1)) and the vasodilator, hydralazine (0.75 mg . kg(-1) . day(-1)). The effects were quantitated in vivo using an enface method that optimizes the observation of endothelial surfaces after immunohistochemical staining for CD68. Both agents significantly and comparably reduced blood pressure over 4-week treatment course. Both valsartan and hydralazine profoundly reduced monocyte adhesion compared with nontreated controls, with valsartan having a modestly more reductive effect. Both agents also reduced the intima and medial thickening with valsartan reducing the mean thickness modestly more than hydralazine. Our data confirms that the reduction of blood pressure is effective method to reduce monocyte adhesion. Also, our date demonstrates that valsartan has a modest beneficial effect on monocyte adhesion to endothelial cells and arterial intima-medial vessel thickening beyond its action as an antihypertensive agent.
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Affiliation(s)
- Fuki Ikeda
- Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
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Abstract
There is convincing evidence that angiotensin II, through activation of the angiotensin II type 1 (AT1) receptor, is involved in the atherosclerotic process. Similarly, angiotensin receptor blockers decrease vascular inflammation, hypertrophy and thrombosis, which are the key components of the progression of atherosclerosis. In addition, in several animal models, angiotensin receptor blockade was able to inhibit atherosclerosis. However, the effects of angiotensin receptor blockers on clinical outcome in cardiovascular patients remains to be established. Contradictory results have been found on the reduction of the risk on myocardial infarctions and in-stent restenosis, although there is solid evidence for cerebroprotective effects of these receptor blockers. These differences may be related to the role of the AT2 receptor. This review discusses the role of angiotensin II and angiotensin receptor blockers in the atherosclerotic process and its translation into clinical practice.
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Affiliation(s)
- Adriaan A Voors
- University Medical Center Groningen, Thoraxcenter, Department of Cardiology, Groningen, The Netherlands.
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Basso N, Cini R, Pietrelli A, Ferder L, Terragno NA, Inserra F. Protective effect of long-term angiotensin II inhibition. Am J Physiol Heart Circ Physiol 2007; 293:H1351-8. [PMID: 17557916 DOI: 10.1152/ajpheart.00393.2007] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experimental studies indicate that angiotensin II (ANG II) through its type 1 receptor (AT(1)) promotes cardiovascular hypertrophy and fibrosis. Therefore, the aim of this study was to analyze whether chronic long-term inhibition of the renin-angiotensin system (RAS) can prevent most of the deleterious effects due to aging in the cardiovascular system of the normal rat. The main objective was to compare two strategies of ANG II blockade: a converting enzyme inhibitor (CEI) and an AT(1) receptor blocker (AT(1)RB). A control group remained untreated; treatment was initiated 2 wk after weaning. A CEI, enalapril (10 mg.kg(-1).day(-1)), or an AT(1)RB, losartan (30 mg.kg(-1).day(-1)), was used to inhibit the RAS. Systolic blood pressure, body weight, and water and food intake were recorded over the whole experimental period. Heart, aorta, and mesenteric artery weight as well as histological analysis of cardiovascular structure were performed at 6 and 18 mo. Twenty animals in each of the three experimental groups were allowed to die spontaneously. The results demonstrated a significant protective effect on the function and structure of the cardiovascular system in all treated animals. Changes observed at 18 mo of age in the hearts and aortas were quite significant, but each treatment completely abolished this deterioration. The similarity between the results detected with either enalapril or losartan treatment clearly indicates that most of the effects are exerted through AT(1) receptors. An outstanding finding was the significant and similar prolongation of life span in both groups of treated animals compared with untreated control animals.
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Affiliation(s)
- Nidia Basso
- Cardiovascular Pathophysiology Institute, Department of Pathology, School of Medicine, University of Buenos Aires, Argentina.
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Miller SJ, Norton LE, Murphy MP, Dalsing MC, Unthank JL. The role of the renin-angiotensin system and oxidative stress in spontaneously hypertensive rat mesenteric collateral growth impairment. Am J Physiol Heart Circ Physiol 2007; 292:H2523-31. [PMID: 17277018 DOI: 10.1152/ajpheart.01296.2006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent clinical and animal studies have shown that collateral artery growth is impaired in the presence of vascular risk factors, including hypertension. Available evidence suggests that angiotensin-converting enzyme inhibitors (ACEI) promote collateral growth in both hypertensive humans and animals; however, the specific mechanisms are not established. This study evaluated the hypothesis that collateral growth impairment in hypertension is mediated by excess superoxide produced by NAD(P)H oxidase in response to stimulation of the ANG II type 1 receptor. After ileal artery ligation, mesenteric collateral growth did not occur in untreated, young, spontaneously hypertensive rats. Significant luminal expansion occurred in collaterals of spontaneously hypertensive rats treated with the superoxide dismutase mimetic tempol, the NAD(P)H oxidase inhibitor apocynin, and the ACEI captopril, but not ANG II type 1 (losartan) or type 2 (PD-123319) receptor blockers. The ACEI enalapril produced equivalent reduction of arterial pressure as captopril but did not promote luminal expansion. This suggests the effects of captopril on collateral growth might result from its antioxidant properties. RT-PCR demonstrated that ANG II type 1 receptor and angiotensinogen expression was reduced in collaterals of untreated rats. This local suppression of the renin angiotensin system provides a potential explanation for the lack of effect of enalapril and losartan on collateral growth. The results demonstrate the capability of antioxidant therapies, including captopril, to reverse impaired collateral artery growth and the novel finding that components of the local renin angiotensin system are naturally suppressed in collaterals.
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Affiliation(s)
- Steven J Miller
- Department of Surgery, Indiana University Medical Center, 1001 West Tenth Street, Indianapolis, IN 46202-2879, USA
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BAUMANN M, MEGENS R, BARTHOLOME R, DOLFF S, van ZANDVOORT MA, SMITS JF, STRUIJKER-BOUDIER HA, De MEY JG. Prehypertensive Renin-Angiotensin-Aldosterone System Blockade in Spontaneously Hypertensive Rats Ameliorates the Loss of Long-Term Vascular Function. Hypertens Res 2007; 30:853-61. [DOI: 10.1291/hypres.30.853] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Machingal MA, Ramanan SV. A steady-state electrochemical model of vascular smooth muscle cells. Biophys J 2006; 91:1648-62. [PMID: 16766616 PMCID: PMC1544296 DOI: 10.1529/biophysj.105.078923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 05/19/2006] [Indexed: 11/18/2022] Open
Abstract
A model of the steady-state electrochemical response of vascular smooth muscle cells to external stimuli is presented, which accounts for K, Na, and Ca fluxes. The results of the model are broadly in accordance with experimental data 1), at various transmural pressures; 2), with channel and pump blockade; and 3), under manipulation of external ionic concentrations. The model exhibits dual stable states which sometimes coexist, and abrupt transitions between these states may account for nongraded responses in arteries as external potassium or pressure is varied. The simulations suggest that changes in the intracellular sodium concentration ([Na]i) often accompany smooth muscle responses. For example, [Na]i values vary threefold over the range of pressures from 10 to 100 mmHg.
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Affiliation(s)
- Masood A Machingal
- AU-KBC Research Centre, MIT Campus of Anna University, Chromepet, Chennai, India 600044, USA
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Gómez-Garre D, Martín-Ventura JL, Granados R, Sancho T, Torres R, Ruano M, García-Puig J, Egido J. Losartan improves resistance artery lesions and prevents CTGF and TGF-beta production in mild hypertensive patients. Kidney Int 2006; 69:1237-44. [PMID: 16482098 DOI: 10.1038/sj.ki.5000034] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although structural and functional changes of resistance arteries have been proposed to participate in arterial hypertension (HTA) outcome, not all therapies may correct these alterations, even if they normalize the blood pressure (BP). The aim of this study was to investigate the mechanisms of the protection afforded by the angiotensin receptor antagonist losartan in resistance arteries from patients with essential HTA. In all, 22 untreated hypertensive patients were randomized to receive losartan or amlodipine for 1 year and the morphological characteristics of resistance vessels from subcutaneous biopsies were evaluated. Protein expression of connective tissue growth factor (CTGF), transforming growth factor beta (TGF-beta), and collagens III and IV was detected by immunohistochemistry. In comparison with normotensive subjects, resistance arteries from hypertensive patients showed a significant media:lumen (M/L) ratio increment and a higher protein expression of CTGF, TGF-beta, and collagens. After 1 year of treatment, both losartan and amlodipine similarly controlled BP. However, M/L only decreased in patients under losartan treatment, whereas in the amlodipine-treated group this ratio continued to increase significantly. The administration of losartan prevented significant increments in CTGF, TGF-beta, and collagens in resistance arteries. By contrast, amlodipine-treated patients showed a higher vascular CTGF, TGF-beta, and collagen IV staining than before treatment. Our results show that the administration of losartan, but not amlodipine, to hypertensive patients improves structural abnormalities and prevents the production of CTGF and TGF-beta in small arteries, despite similar BP lowering. These data may explain the molecular mechanisms of the better vascular protection afforded by drugs interfering with the renin-angiotensin system.
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Affiliation(s)
- D Gómez-Garre
- Vascular Biology and Atherosclerosis Research Laboratory, Medicina Interna III, Hospital Clínico San Carlos, Madrid, Spain
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Shirakawa H, Koseki T, Ohinata K, Hashizume K, Komai M. Rice bran fractions improve blood pressure, lipid profile, and glucose metabolism in stroke-prone spontaneously hypertensive rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:1914-20. [PMID: 16506853 DOI: 10.1021/jf052561l] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Effect of dietary supplementation of two types of rice bran fraction on blood pressure (BP), lipid profile, and glucose metabolism in stroke-prone spontaneously hypertensive rats was studied. Male 4-week-old rats were divided into one group fed the AIN-93M-based control (C) diet and two groups fed diet supplemented with 60 g/kg of Driselase and ethanol fractions (DF and EF, respectively) of rice bran. After 8 weeks feeding, the BP decreased in the DF and EF groups in comparison with the C group (p < 0.01). Plasma ACE inhibitory activity, BUN, BUN/creatinine ratio, albumin, triglyceride, and glucose levels were lower in the DF and EF groups than in the C group (p < 0.01). Plasma nitric oxide and urinary 8-hydroxy-2'-deoxyguanosine levels were lower in the DF and EF groups than in the C group (p < 0.01). Rice bran fractions appear to have a beneficial dietary component that improves hypertension, hyperlipidemia, and hyperglycemia.
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Rizzoni D, Rossi GP, Porteri E, Sticchi D, Rodella L, Rezzani R, Sleiman I, De Ciuceis C, Paiardi S, Bianchi R, Nussdorfer GG, Agabiti-Rosei E. Bradykinin and matrix metalloproteinases are involved the structural alterations of rat small resistance arteries with inhibition of ACE and NEP. J Hypertens 2004; 22:759-66. [PMID: 15126918 DOI: 10.1097/00004872-200404000-00019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND AIM Increased vascular resistance is a hallmark of hypertension and involves structural alterations, which may entail smooth muscle cell hypertrophy or hyperplasia, or qualitative or quantitative changes in extracellular matrix (ECM) proteins. Since the renin-angiotensin-aldosterone system modulates these changes, we investigated the effects of 8 weeks of treatment with an angiotensin-converting enzyme (ACE) inhibitor, ramipril (RAM), or a dual ACE and neutral endopeptidase (NEP) inhibitor, MDL-100240 (MDL), on mesenteric small artery structure and ECM proteins in mRen2-transgenic rats (TGRs), an animal model of hypertension with severe cardiovascular damage. MATERIALS AND METHODS Thirty-five 5-week-old rats were included in the study: six TGRs received RAM; five TGRs RAM + the bradykinin receptor inhibitor, icatibant; six TGRs, MDL; and five TGRs MDL + icatibant, while eight TGRs and five normotensive Sprague-Dawley controls were kept untreated. Mesenteric small arteries were dissected and mounted on a micromyograph. The media-to-lumen ratio (M/L) was then calculated. Vascular metalloproteinase (MMP) content was evaluated by zymography. RESULTS In untreated TGRs severe hypertension was associated with inward eutrophic remodelling of small arteries. Both RAM and MDL prevented the increase in blood pressure and M/L and decreased MMPs. Icatibant blunted the effect of MDL on BP, M/L and MMPs. CONCLUSIONS Changes in collagenase activity induced by ramipril and MDL are associated with prevention of small artery structural alterations in TGRs. Furthermore, MDL-induced enhancement of bradykinin could play a role in both the prevention of vascular structural alterations and in the stimulation of MMPs.
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Affiliation(s)
- Damiano Rizzoni
- Department of Medical and Surgical Sciences, University of Brescia, DMCS - Clinica Medica 4, University of Padua, Italy.
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Pereira LMM, Almeida JR, Mandarim-de-Lacerda CA. Kidney adaptation in nitric oxide-deficient Wistar and spontaneously hypertensive rats. Life Sci 2004; 74:1375-86. [PMID: 14706568 DOI: 10.1016/j.lfs.2003.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We investigated the renal structural and functional consequences of nitric oxide (NO) deficiency co-treated with angiotensin-converting enzyme inhibitor (ACEi) in 20 adult male Wistar rats and 20 spontaneously hypertensive rats (SHR). The animals were separated into eight groups (n = 5) and treated for 30 days: Control, L-NAME (NO deficient group), Enalapril, L-NAME + Enalapril. The elevated blood pressure in NO deficient rats was partially reduced by enalapril. Serum creatinine was elevated in L-NAME-SHRs and effectively treated with enalapril. The proteinuria was significantly higher only in L-NAME-SHRs, and this was reduced by treatment with ACEi. The glomerular volume density (Vv(gl)) in L-NAME rats, both Wistar and SHR, was greater than in matched control rats, and enalapril treatment effectively prevented this Vv(gl) increase. No significant differences were observed in tubular volume density, Vv(tub), or tubular surface density, Sv(tub), in all Wistar groups. The Vv(tub) was smaller in L-NAME-SHRs than in control SHRs, and this tubular alteration was not prevented by enalapril. The Sv(tub) was not different among the SHR groups. In Wistar rats no changes were seen in vascular surface density, but a greatly increased cortical vascular volume density was seen in the enalapril treated rats. The vascular length density was greatly diminished in NO deficient rats that was effectively prevented with enalapril treatment. The vascular cortical renal stereological indices are normally reduced in SHRs. Administration of enalapril, but not L-NAME, changed this tendency. However, enalapril was not totally effective in preventing vascular damage in SHR NO deficient animals.
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Affiliation(s)
- Leila Maria Meirelles Pereira
- Laboratory of Morphometry and Cardiovascular Morphology, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro, 87 fds. 20551-030, Rio de Janeiro, RJ, Brazil
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Azevedo LF, Brum PC, Mattos KC, Junqueira CM, Rondon MUPB, Barretto ACP, Negrão CE. Effects of losartan combined with exercise training in spontaneously hypertensive rats. Braz J Med Biol Res 2003; 36:1595-603. [PMID: 14576915 DOI: 10.1590/s0100-879x2003001100018] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigate whether combined treatment with losartan, an angiotensin II receptor blocker, and exercise training (ET) in spontaneously hypertensive rats (SHR) would have an additive effect in reducing hypertension and improving baroreflex sensitivity when compared with losartan alone. Male SHR (8 weeks old) were assigned to 3 groups: sedentary placebo (SP, N = 16), sedentary under losartan treatment (SL, N = 11; 10 mg kg-1 day-1, by gavage), and ET under losartan treatment (TL, N = 10). ET was performed on a treadmill 5 days/week for 60 min at 50% of peak VO2, for 18 weeks. Blood pressure (BP) was measured with a catheter inserted into the carotid artery, and cardiac output with a microprobe placed around the ascending aorta. The baroreflex control of heart rate was assessed by administering increasing doses of phenylephrine and sodium nitroprusside (iv). Losartan significantly reduced mean BP (178 16 vs 132 12 mmHg) and left ventricular hypertrophy (2.9 0.4 vs 2.5 0.2 mg/g), and significantly increased baroreflex bradycardia and tachycardia sensitivity (1.0 0.3 vs 1.7 0.5 and 2.0 0.7 vs 3.2 1.7 bpm/mmHg, respectively) in SL compared with SP. However, losartan combined with ET had no additional effect on BP, baroreflex sensitivity or left ventricular hypertrophy when compared with losartan alone. In conclusion, losartan attenuates hypertension and improves baroreflex sensitivity in SHR. However, ET has no synergistic effect on BP in established hypertension when combined with losartan, at least at the dosage used in this investigation.
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Affiliation(s)
- L F Azevedo
- Instituto do Coração (InCor), Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
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Duke LM, Paull JRA, Widdop RE. Cardiovascular status following combined angiotensin-converting enzyme and AT1 receptor inhibition in conscious spontaneously hypertensive rats. Clin Exp Pharmacol Physiol 2003; 30:317-23. [PMID: 12859420 DOI: 10.1046/j.1440-1681.2003.03837.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
1. Combined treatment of spontaneously hypertensive rats (SHR) with AT1 receptor antagonists and angiotensin-converting enzyme (ACE) inhibitors has been shown to reduce mean arterial pressure (MAP) more than monotherapy with either agent. The aims of the present study were to investigate the effects of chronic dual renin-angiotensin system (RAS) inhibition using non-hypotensive doses of the AT1 receptor antagonist candesartan cilexetil and the ACE inhibitor perindopril on cardiovascular function and structure. 2. Adult male SHR, aged 15 weeks, were divided into four groups: (i) candesartan cilexetil (0.5 mg/kg per day in drinking water); (ii) perindopril (0.3 mg/kg per day in drinking water); (iii) combined treatment (dual RAS inhibition); or (iv) the appropriate vehicle (0.1% ethanol/0.1% polyethylene glycol/1.5 mmol/l sodium bicarbonate dissolved in water for candesartan cilexetil; distilled water for perindopril). Systolic blood pressure was measured weekly using the tail-cuff method and urinary microalbuminuria was measured fortnightly. 3. After 4 weeks, rats were instrumented for intravenous drug administration and measurement of MAP. At this time, the cardiovascular effects of angiotensin (Ang) I and AngII (5-20 ng) and sodium nitroprusside (SNP) and acetylcholine (ACh; 1-5 micro g) were assessed. In addition, left ventricular : bodyweight and media : lumen ratios were determined as indices of cardiac and vascular hypertrophy, respectively. 4. Candesartan cilexetil and perindopril alone had minimal effect on MAP when measured both directly and indirectly, whereas direct MAP was significantly decreased in the combined treatment group (131 +/- 6 mmHg; P < 0.05) compared with the vehicle group (156 +/- 9 mmHg). Pressor responses to AngI were significantly decreased in all groups compared with the vehicle-treated group and pressor responses to AngII were significantly decreased in the candesartan cilexetil-treated (P < 0.01) and combined treatment groups (P < 0.01) compared with the vehicle-treated group. Depressor responses to ACh and SNP were not significantly affected by any of the antihypertensive therapies compared with vehicle-treated SHR. 5. Vascular hypertrophy was significantly decreased in the candesartan cilexetil and combined groups compared with the vehicle-treated group, whereas cardiac hypertrophy was reduced, with the rank order of effect being: dual RAS inhibition > perindopril > candesartan cilexetil. Urinary albumin tended to decrease with dual RAS inhibition, but was not significantly affected by this short-term treatment. 6. These results demonstrate the efficacy of low-dose dual RAS inhibition as an antihypertensive modality, at least in SHR, not only in reducing arterial pressure, but also in improving cardiovascular structure.
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Affiliation(s)
- Lisa M Duke
- Department of Pharmacology, Monash University, Melbourne, Victoria, Australia
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Palmgren E, Widgren B, Aurell M, Herlitz H. Increased renal vascular sensitivity to angiotensin II in hypertension is due to decreased response to prostaglandins. J Hypertens 2003; 21:969-76. [PMID: 12714872 DOI: 10.1097/00004872-200305000-00022] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES An enhanced sensitivity to angiotensin II in the renal circulation has been demonstrated in the pre-hypertensive phase both in the spontaneously hypertensive rat and in man. To further characterize this abnormality and the role of prostanoids, renal haemodynamics in normotensive young men with a positive (PFH) or a negative (NFH) family history of hypertension were studied. METHODS Renal vascular reactivity was assessed during infusion of angiotensin II with and without inhibition of prostaglandin synthesis. Normotensive men with PFH (n = 13) and with NFH (n = 10) with a mean age of 38 years were given on two different occasions: (i). angiotensin II infusion i.v. (0.1, 0.5 and 1.0 ng/kg per min) and (ii). angiotensin II infusion after inhibition of prostaglandin synthesis with indomethacin (150 mg daily three consecutive days). Glomerular filtration rate (GFR) and renal plasma flow were measured with renal clearances of chromium edetic acid and para-aminohippuric acid. RESULTS Before angiotensin II challenge, the groups did not differ with respect to blood pressure, body mass index, plasma renin activity, GFR, renal blood flow (RBF) or urinary sodium excretion. There was no significant difference in systolic or diastolic blood pressure response to angiotensin II between the two groups. In PFH, the lowest angiotensin II dose caused a significant decrease in RBF and increase in renal vascular resistance (RVR) from baseline (P < 0.01 for both). In NFH, only the highest angiotensin II dose produced a significant decrease in RBF and increase in RVR (P < 0.01 for both). During inhibition of prostaglandin synthesis, all three angiotensin II doses caused a significant decrease in RBF (P < 0.02) and increase in RVR (P < 0.02) also in NFH. The renal haemodynamic difference between PFH and NFH was thus eliminated. CONCLUSIONS These findings indicate that young human subjects with a positive family history of hypertension have a defective vasodilator prostaglandin system, which is responsible for increased renal vascular sensitivity to angiotensin II. Enhanced renal vasoconstriction may be an early event leading to the generation of primary hypertension.
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Affiliation(s)
- Eva Palmgren
- Department of Nephrology, Sahlgrenska University Hospital, Göteborg, Sweden
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Rizzoni D, Rodella L, Porteri E, Rezzani R, Sleiman I, Paiardi S, Guelfi D, De Ciuceis C, Boari GEM, Bianchi R, Agabiti-Rosei E. Effects of Losartan and Enalapril at Different Doses on Cardiac and Renal Interstitial Matrix in Spontaneously Hypertensive Rats. Clin Exp Hypertens 2003; 25:427-41. [PMID: 14596367 DOI: 10.1081/ceh-120024986] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have evaluated the effects of an ACE inhibitor, enalapril (ENA) and of an angiotensin II receptor blocker, losartan (LOS), administered either at hypotensive or non-hypotensive dosage, on the cardiac and renal structure of spontaneously hypertensive rats (SHR). Forty-eight rats were included in the study: eight SHR were treated with low-dose (ld, 1 mg/kg/day) ENA; eight with low-dose (ld, 0.5 mg/kg/day) LOS; eight with high-dose (hd, 25 mg/kg/day) ENA; eight with high-dose (hd, 15 mg/kg/day) LOS; while eight Wistar-Kyoto (WKY) and eight SHR were kept untreated (unt). Treatment was given from the 4th to the 12th week of age. Systolic blood pressure (SBP) was measured non-invasively every week. The left ventricular weight to body weight (RLVM) and the left + right kidney weight (RKW) to body weight was measured, and the cardiac and glomerular interstitial collagen content was evaluated using sirius red staining and image analysis. In addition, cardiac metalloproteinases activity (43 kDa MMP, MMP-2, and MMP-9) was evaluated by zymography. A significant reduction in RLVM was observed in SHR given ENA hd or LOS hd. Cardiac collagen was significantly reduced in SHR ENA hd and SHR LOS hd as well as in SHR LOS ld, but not in SHR ENA ld. The 43 kDa MMP collagenase activity was greater in WKY unt compared with SHR unt, being normalized only in SHR ENA hd. The gelatinase activity of MMP-9 showed a trend similar to 43 kDa MMP, but differences between SHR and WKY unt were only of borderline statistical significance. No difference among groups was observed in MMP-2 activity. No significant differences in RKW was observed between groups. However, the collagen content in the glomerular perivascular space was significantly reduced in all treated groups, including those given ld, compared with SHR unt. In conclusion, LOS and ENA showed a similar preventive effect on the increase of RLVM in SHR, but, at least in part, different effects on the extracellular matrix in different organs, being cardiac collagen less sensitive to low dose (ld) ACE inhibition.
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Affiliation(s)
- Damiano Rizzoni
- Chair of Internal Medicine, Department of Medical and Surgical Sciences, University of Brescia, Italy.
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Touyz RM. The role of angiotensin II in regulating vascular structural and functional changes in hypertension. Curr Hypertens Rep 2003; 5:155-64. [PMID: 12642016 DOI: 10.1007/s11906-003-0073-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A major hemodynamic abnormality in hypertension is increased peripheral resistance due to changes in vascular structure and function. Structural changes include reduced lumen diameter and arterial wall thickening. Functional changes include increased vasoconstriction and/or decreased vasodilation. These processes are influenced by many humoral factors, of which angiotensin II (Ang II) seems to be critical. At the cellular level, Ang II stimulates vascular smooth muscle cell growth, increases collagen deposition, induces inflammation, increases contractility, and decreases dilation. Molecular mechanisms associated with these changes in hypertension include upregulation of many signaling pathways, including tyrosine kinases, mitogen-activated protein kinases, RhoA/Rho kinase, and increased generation of reactive oxygen species. This review focuses on the role of Ang II in vascular functional and structural changes of small arteries in hypertension. In addition, cellular processes whereby Ang II influences vessels in hypertension are discussed. Finally, novel concepts related to signaling pathways by which Ang II regulates vascular smooth muscle cells in hypertension are introduced.
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Affiliation(s)
- Rhian M Touyz
- Clinical Research Institute of Montreal, 110 Pine Avenue West, Canada.
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Hale T, Okabe H, Bushfield T, Heaton J, Adams M. Recovery of Erectile Function after Brief Aggressive Antihypertensive Therapy. J Urol 2002. [DOI: 10.1016/s0022-5347(05)64919-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- T.M. Hale
- From the Departments of Pharmacology and Toxicology and Urology, Queen’s University, Kingston, Ontario, Canada, and Department of Urology, Okayama University Medical School, Okayama, Japan
| | - H. Okabe
- From the Departments of Pharmacology and Toxicology and Urology, Queen’s University, Kingston, Ontario, Canada, and Department of Urology, Okayama University Medical School, Okayama, Japan
| | - T.L. Bushfield
- From the Departments of Pharmacology and Toxicology and Urology, Queen’s University, Kingston, Ontario, Canada, and Department of Urology, Okayama University Medical School, Okayama, Japan
| | - J.P.W. Heaton
- From the Departments of Pharmacology and Toxicology and Urology, Queen’s University, Kingston, Ontario, Canada, and Department of Urology, Okayama University Medical School, Okayama, Japan
| | - M.A. Adams
- From the Departments of Pharmacology and Toxicology and Urology, Queen’s University, Kingston, Ontario, Canada, and Department of Urology, Okayama University Medical School, Okayama, Japan
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