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Barros PR, Costa TJ, Akamine EH, Tostes RC. Vascular Aging in Rodent Models: Contrasting Mechanisms Driving the Female and Male Vascular Senescence. FRONTIERS IN AGING 2021; 2:727604. [PMID: 35821995 PMCID: PMC9261394 DOI: 10.3389/fragi.2021.727604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 08/25/2021] [Indexed: 12/12/2022]
Abstract
Increasing scientific interest has been directed to sex as a biological and decisive factor on several diseases. Several different mechanisms orchestrate vascular function, as well as vascular dysfunction in cardiovascular and metabolic diseases in males and females. Certain vascular sex differences are present throughout life, while others are more evident before the menopause, suggesting two important and correlated drivers: genetic and hormonal factors. With the increasing life expectancy and aging population, studies on aging-related diseases and aging-related physiological changes have steeply grown and, with them, the use of aging animal models. Mouse and rat models of aging, the most studied laboratory animals in aging research, exhibit sex differences in many systems and physiological functions, as well as sex differences in the aging process and aging-associated cardiovascular changes. In the present review, we introduce the most common aging and senescence-accelerated animal models and emphasize that sex is a biological variable that should be considered in aging studies. Sex differences in the cardiovascular system, with a focus on sex differences in aging-associated vascular alterations (endothelial dysfunction, remodeling and oxidative and inflammatory processes) in these animal models are reviewed and discussed.
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Affiliation(s)
- Paula R. Barros
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Tiago J. Costa
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eliana H. Akamine
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- *Correspondence: Rita C. Tostes, ; Eliana H. Akamine,
| | - Rita C. Tostes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- *Correspondence: Rita C. Tostes, ; Eliana H. Akamine,
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2
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Ilic S, Stojiljkovic N, Stojanovic N, Stoiljkovic M, Mitic K, Salinger-Martinovic S, Randjelovic P. Effects of oleuropein on rat's atria and thoracic aorta: a study of antihypertensive mechanisms. Can J Physiol Pharmacol 2021; 99:110-114. [PMID: 33449845 DOI: 10.1139/cjpp-2020-0363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oleuropein (OLE) is the main bioactive ingredient in the leaves of the olive plant Olea europaea L. (Oleaceae), which has proven beneficial due to the antiinflammatory, antiatherogenic, anticancer, antimicrobial, and antiviral effects. This study aimed to investigate the antihypertensive and vasodilator potential of OLE by analyzing its acute effects on spontaneous atrial contractions and vasomotor responses of the isolated thoracic aorta in rats. We showed that the application of OLE induces negative chronotropic and inotropic effects on the heart. OLE also causes mild aortic vasodilation given that the maximal reduction in tension of intact aortic rings precontracted with phenylephrine was approximately 30%. This vasodilation is likely dependent on the nitric oxide released from the endothelium based on the effect obtained on denuded and phenylephrine precontracted aortic rings and responses reordered following vasoconstriction induced by high concentrations of K+ and heparin. Our findings provide a basis for further testing of OLE cardiovascular effects, which may lead to subsequent clinical research for its application in the treatment of hypertension and heart disease.
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Affiliation(s)
- Sonja Ilic
- Department of Physiology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Nenad Stojiljkovic
- Department of Physiology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Nikola Stojanovic
- Department of Physiology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Milan Stoiljkovic
- Department of Pharmacology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Katarina Mitic
- Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Sonja Salinger-Martinovic
- Clinic for Cardiovascular Diseases, Clinical Center Niš, Blvd dr Zorana Djindjica 48, Niš, Serbia.,Department of Cardiology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
| | - Pavle Randjelovic
- Department of Physiology, Faculty of Medicine, University of Niš, Blvd dr Zorana Djindjica 81, Niš, Serbia
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Ribeiro Junior RF, Fiorim J, Marques VB, de Sousa Ronconi K, Botelho T, Grando MD, Bendhack LM, Vassallo DV, Stefanon I. Vascular activation of K+ channels and Na+-K+ ATPase activity of estrogen-deficient female rats. Vascul Pharmacol 2017; 99:23-33. [DOI: 10.1016/j.vph.2017.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/09/2017] [Accepted: 09/09/2017] [Indexed: 11/27/2022]
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4
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Caliman IF, Bernabe CS, de Melo AF, Brasil GA, do Nascimento AM, de Lima EM, Figueiredo SG, de Andrade TU, Bissoli NS. Long-term treatment with Nandrolone Decanoate impairs mesenteric vascular relaxation in both sedentary and exercised female rats. Steroids 2017; 120:7-18. [PMID: 28192127 DOI: 10.1016/j.steroids.2017.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 12/09/2016] [Accepted: 02/01/2017] [Indexed: 12/24/2022]
Abstract
Nandrolone Decanoate (ND) is an Anabolic Androgenic Steroid (AAS) that under abusive regimen can lead to multiple physiological adverse effects. Studies of AAS-mediated cardiovascular (CV) alterations were mostly taken from male subjects, even though women are also susceptible to the effects of AAS and gender-specific differences in susceptibility to vascular diseases exist. Here we investigate ND-induced vascular reactivity alterations in both sedentary and exercised female rats and whether these alterations depend on endothelium-derived factors. We show that chronic exposure of female Wistar rats to ND (20mg/Kg/week for 4weeks) impaired the vascular mesenteric bed (MVB) reactivity to vasodilator (acetylcholine) agonist. The endothelium-dependent Nitric Oxide (NO) component was reduced in ND-treated rats, whereas neither the endothelium-derived hyperpolarizing factor (EDHF) component nor prostanoids were altered in the MVBs. Endothelial dysfunction observed in ND-treated rats was associated with decreased eNOS (Ser1177) and Akt (Ser473) phosphorylation sites and upregulation of iNOS and NADPH oxidase expression. Exercise training by weight lifting in water did not improve the vascular alterations induced by ND treatment. ND treatment also significantly reduced the serum levels of estradiol in females, overriding its CV protective effect. These results help uncover the role of ND modulating endothelial function in the setting of CV disease caused by the abuse of AAS in females. If this translates to humans, young women abusing AAS can potentially lose the cardio protective effect rendered by estrogen and be more susceptible to CV alterations.
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Affiliation(s)
- Izabela F Caliman
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil.
| | - Cristian S Bernabe
- Department of Anatomy & Cell Biology, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Program in Medical Neurosciences, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Antônio F de Melo
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Girlândia A Brasil
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Andrews M do Nascimento
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Ewelyne M de Lima
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil; Department of Pharmaceutical Sciences, University of Vila Velha, Vila Velha, ES, Brazil
| | - Suely G Figueiredo
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Tadeu U de Andrade
- Department of Pharmaceutical Sciences, University of Vila Velha, Vila Velha, ES, Brazil
| | - Nazaré S Bissoli
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
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5
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Wong CM, Au CL, Tsang SY, Lau CW, Yao X, Cai Z, Chung ACK. Role of inducible nitric oxide synthase in endothelium-independent relaxation to raloxifene in rat aorta. Br J Pharmacol 2017; 174:718-733. [PMID: 28138957 DOI: 10.1111/bph.13733] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/04/2016] [Accepted: 01/18/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Raloxifene can induce both endothelium-dependent and -independent relaxation in different arteries. However, the underlying mechanisms by which raloxifene triggers endothelium-independent relaxation are still incompletely understood. The purpose of present study was to examine the roles of NOSs and Ca2+ channels in the relaxant response to raloxifene in the rat isolated, endothelium-denuded aorta. EXPERIMENTAL APPROACH Changes in isometric tension, cGMP, nitrite, inducible NOS protein expression and distribution in response to raloxifene in endothelium-denuded aortic rings were studied by organ baths, radioimmunoassay, Griess reaction, western blot and immunohistochemistry respectively. KEY RESULTS Raloxifene reduced the contraction to CaCl2 in a Ca2+ -free, high K+ -containing solution in intact aortic rings. Raloxifene also acutely relaxed the aorta primarily through an endothelium-independent mechanism involving NO, mostly from inducible NOS (iNOS) in vascular smooth muscle layers. This effect of raloxifene involved the generation of cGMP and nitrite. Also, it was genomic in nature, as it was inhibited by a classical oestrogen receptor antagonist and inhibitors of RNA and protein synthesis. Raloxifene-induced stimulation of iNOS gene expression was partly mediated through activation of the NF-κB pathway. Raloxifene was more potent than 17β-estradiol or tamoxifen at relaxing endothelium-denuded aortic rings by stimulation of iNOS. CONCLUSIONS AND IMPLICATIONS Raloxifene-mediated vasorelaxation in rat aorta is independent of a functional endothelium and is mediated by oestrogen receptors and NF-κB. This effect is mainly mediated through an enhanced production of NO, cGMP and nitrite, via the induction of iNOS and inhibition of calcium influx through Ca2+ channels in rat aortic smooth muscle.
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Affiliation(s)
- Chi Ming Wong
- Partner State Key Laboratory of Environmental and Biological Analysis and Department of Chemistry, Hong Kong Baptist University (HKBU), Hong Kong.,HKBU Institute for Research and Continuing Education, Shenzhen, China.,School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong
| | - Chak Leung Au
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong
| | - Suk Ying Tsang
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Hong Kong
| | - Chi Wai Lau
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong
| | - Xiaoqiang Yao
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong
| | - Zongwei Cai
- Partner State Key Laboratory of Environmental and Biological Analysis and Department of Chemistry, Hong Kong Baptist University (HKBU), Hong Kong.,HKBU Institute for Research and Continuing Education, Shenzhen, China
| | - Arthur Chi-Kong Chung
- Partner State Key Laboratory of Environmental and Biological Analysis and Department of Chemistry, Hong Kong Baptist University (HKBU), Hong Kong.,HKBU Institute for Research and Continuing Education, Shenzhen, China
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6
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Chang CC, Lee WS, Chuang CL, Hsin IF, Hsu SJ, Chang T, Huang HC, Lee FY, Lee SD. Effects of raloxifene on portal hypertension and hepatic encephalopathy in cirrhotic rats. Eur J Pharmacol 2017; 802:36-43. [PMID: 28238769 DOI: 10.1016/j.ejphar.2017.02.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 01/13/2023]
Abstract
Raloxifene, a selective estrogen receptor modulator, has been used extensively for osteoporosis. In addition to the effect of osteoporosis treatment, emerging evidences show that raloxifene affects the vascular function in different tissues. Cirrhosis is characterized with portal hypertension and complicated with hepatic encephalopathy. Portal hypertension affects portal-systemic shunt which leads to hepatic encephalopathy that the vascular modulation might influence severity of hepatic encephalopathy. Herein, we evaluated the impact of raloxifene on bile duct ligation (BDL)-induced cirrhotic rats. The female Sprague-Dawley rats received BDL plus ovariectomy or sham-operation. Four weeks later, rats were divided into 2 subgroups respectively to receive of raloxifene (10mg/kg/day) or saline (vehicle) for 14 days. On the 43th day, motor activities and hemodynamic parameters were measured. Hepatic and vascular mRNA and protein expressions were determined. The histopathological change of liver was examined. We found that the liver biochemistry, ammonia level and motor activity were similar between cirrhotic rats with or without raloxifene administration. The hemodynamic parameters were not significantly different except that raloxifene reduced portal venous inflow. Raloxifene exacerbated hepatic fibrosis and up-regulated hepatic endothelin-1 and cyclooxygenase 2 protein expressions. In addition, raloxifene modulated the mRNA expressions of endothelial nitric oxide synthase, cyclooxygenase and endothelin-1 in the superior mesenteric artery and collateral vessel. In conclusion, raloxifene aggravates hepatic fibrosis and decreases portal venous inflow in cirrhotic rats without adversely affecting portal hypertension and hepatic encephalopathy. The modulation of hepatic and vascular endothelin-1, endothelial nitric oxide synthase and cyclooxygenase expressions may play a role in the mechanism.
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Affiliation(s)
- Ching-Chih Chang
- Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Wen-Shin Lee
- Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Chiao-Lin Chuang
- Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - I-Fang Hsin
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Endoscopy Center for Diagnosis and Treatment, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Institute of Pharmacology, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Shao-Jung Hsu
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Ting Chang
- Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Hui-Chun Huang
- Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Fa-Yauh Lee
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Shou-Dong Lee
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Cheng-Hsin General Hospital, Taipei, Taiwan
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7
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Vanhoutte PM, Shimokawa H, Feletou M, Tang EHC. Endothelial dysfunction and vascular disease - a 30th anniversary update. Acta Physiol (Oxf) 2017; 219:22-96. [PMID: 26706498 DOI: 10.1111/apha.12646] [Citation(s) in RCA: 553] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/27/2015] [Accepted: 12/17/2015] [Indexed: 02/06/2023]
Abstract
The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H2 O2 ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive Gi (e.g. responses to α2 -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive Gq (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H2 O2 ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.
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Affiliation(s)
- P. M. Vanhoutte
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
| | - H. Shimokawa
- Department of Cardiovascular Medicine; Tohoku University; Sendai Japan
| | - M. Feletou
- Department of Cardiovascular Research; Institut de Recherches Servier; Suresnes France
| | - E. H. C. Tang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
- School of Biomedical Sciences; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
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8
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Nirwane A, Pawar V, Majumdar A. Therapeutic interventions using a combination of Telmisartan and omega 3-fatty acids in sodium arsenite-induced vascular endothelial dysfunction in rats: modulation through ATP-sensitive K+ channels and eNOS. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2016; 12:143-51. [PMID: 25870973 DOI: 10.1515/jcim-2015-0009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/12/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND Effective diet/drug combinations may show additive or synergistic effects in reducing endothelial risk factors vis-à-vis monotherapies. The study evaluated the effect of combined therapy of Telmisartan and omega 3-fatty acids in sodium arsenite-induced vascular endothelial dysfunction (VED) in rats. METHODS Forty-eight male Wistar rats (180-220 g) were randomized into eight groups; control, sodium arsenite (1.5 mg/kg/day) exposed, sodium arsenite exposure followed by treatment with Telmisartan, omega 3-fatty acids, the combination and/or endothelial modulators for 2 weeks depending on the allocated group. VED was assessed by estimating vascular reactivity. Serum thiobarbituric acid-reactive substances (TBARS), nitrite/nitrate levels, reduced glutathione (GSH) levels, superoxide dismutase (SOD) activity, serum cholesterol and triglyceride levels were also determined. RESULTS Sodium arsenite produced VED by attenuating acetylcholine-induced endothelial relaxation (% Rmax= 45.36), decreasing levels of serum nitrite/nitrate (9.28 μM/mg protein), GSH (16.06 μg/mg of protein), SOD activity (30.69 units/mg protein) and increasing TBARS (0.19 µM/mg protein) compared with control group. The combined therapy with Telmisartan (10 mg/kg/day) and omega 3-fatty acids (180 mg/kg/day) (% Rmax = 80.93, 13.09 µM/mg protein, 25.93 μg/mg of protein, 57.84 units/mg protein and 0.08 µM/mg protein, respectively) significantly abolished the respective derangements induced by sodium arsenite. Further, this combination significantly prevented rise in serum cholesterol and triglyceride levels that was induced by sodium arsenite. However, the ameliorative effects of this combination were abated by N-omega-nitro-L-arginine methyl ester (L-NAME) and glibenclamide. CONCLUSIONS Combined therapy of Telmisartan and omega 3-fatty acids attenuated VED, by activating enzyme nitric oxide synthase (eNOS) through opening of ATP-sensitive K(+) channels.
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Wang X, Wang J, Luo H, Chen C, Pei F, Cai Y, Yang X, Wang N, Fu J, Xu Z, Zhou L, Zeng C. Prenatal lipopolysaccharide exposure causes mesenteric vascular dysfunction through the nitric oxide and cyclic guanosine monophosphate pathway in offspring. Free Radic Biol Med 2015; 86:322-30. [PMID: 26073126 DOI: 10.1016/j.freeradbiomed.2015.05.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/03/2015] [Accepted: 05/26/2015] [Indexed: 01/21/2023]
Abstract
Cardiovascular diseases, such as hypertension, could be programmed in fetal life. Prenatal lipopolysaccharide (LPS) exposure in utero results in increased blood pressure in offspring, but the vascular mechanisms involved are unclear. Pregnant Sprague-Dawley rats were intraperitoneally injected with LPS (0.79mg/kg) or saline (0.5ml) on gestation days 8, 10, and 12. The offspring of LPS-treated dams had higher blood pressure and decreased acetylcholine (ACh)-induced relaxation and increased phenylephrine (PE)-induced contraction in endothelium-intact mesenteric arteries. Endothelium removal significantly enhanced the PE-induced contraction in offspring of control but not LPS-treated dams. The arteries pretreated with l-NAME to inhibit nitric oxide synthase (eNOS) in the endothelium or ODQ to inhibit cGMP production in the vascular smooth muscle had attenuated ACh-induced relaxation but augmented PE-induced contraction to a larger extent in arteries from offspring of control than those from LPS-treated dams. In addition, the endothelium-independent relaxation caused by sodium nitroprusside was also decreased in arteries from offspring of LPS-treated dams. The functional results were accompanied by a reduction in the expressions of eNOS and soluble guanylate cyclase (sGC) and production of NO and cGMP in arteries from offspring of LPS-treated dams. Furthermore, LPS-treated dam's offspring arteries had increased oxidative stress and decreased antioxidant capacity. Three-week treatment with TEMPOL, a reactive oxygen species (ROS) scavenger, normalized the alterations in the levels of ROS, eNOS, and sGC, as well as in the production of NO and cGMP and vascular function in the arteries of the offspring of LPS-treated dams. In conclusion, prenatal LPS exposure programs vascular dysfunction of mesenteric arteries through increased oxidative stress and impaired NO-cGMP signaling pathway.
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Affiliation(s)
- Xinquan Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Jialiang Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Hao Luo
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Fang Pei
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Yue Cai
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Xiaoli Yang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Na Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Jinjuan Fu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Zaichen Xu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Lin Zhou
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China.
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China.
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10
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Lamas AZ, Caliman IF, Dalpiaz PLM, de Melo AF, Abreu GR, Lemos EM, Gouvea SA, Bissoli NS. Comparative effects of estrogen, raloxifene and tamoxifen on endothelial dysfunction, inflammatory markers and oxidative stress in ovariectomized rats. Life Sci 2015; 124:101-9. [PMID: 25623855 DOI: 10.1016/j.lfs.2015.01.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 12/15/2014] [Accepted: 01/08/2015] [Indexed: 12/24/2022]
Abstract
AIM Endothelial dysfunction is considered a premature indication of atherosclerosis and vessel damage and is present in the postmenopausal period. This study compares the influence of estrogen, raloxifene and tamoxifen on factors that affect endothelial function in ovariectomized (OVX) rats. MAIN METHODS The rats were divided into: SHAM; OVX; OVX+estrogen (0.5 μg/kg/day); OVX+raloxifene (2 mg/kg/day) and OVX+tamoxifen (1 mg/kg/day) groups. The acetylcholine vasorelaxation response was evaluated in the mesenteric vascular bed. The vascular oxidative stress and serum inflammatory cytokine levels were monitored, and analyses of eNOS and iNOS were performed. KEY FINDINGS The acetylcholine-induced responses obtained in the OVX were lower than those obtained in the SHAM, and all treatments restored this response. l-NAME reduced and equalized the acetylcholine-induced response in all groups. The attenuation of the acetylcholine-induced responses by aminoguanidine was greater in the OVX. Endothelial dysfunction in OVX was associated with oxidative stress and an increase in iNOS and decrease in eNOS expression. Except for the production of reactive oxidative species (ROS) in the OVX+tamoxifen, treatments improved the nitric oxide component of the relaxation response and normalized both the oxidative stress and the expression of those signaling pathway enzymes. Serum levels of TNF-α and IL-6 were increased in OVX, and treatments normalized these levels. SIGNIFICANCE Raloxifene and tamoxifen have similar anti-inflammatory effects that may be important in improving vascular dysfunction. Tamoxifen did not affect the ROS but improved endothelial dysfunction. The protective effect on endothelial function by these treatments provides evidence of their potential cardiovascular benefits in the postmenopausal period.
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Affiliation(s)
- Aline Zandonadi Lamas
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Izabela Facco Caliman
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Polyana Lima Meireles Dalpiaz
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Antônio Ferreira de Melo
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Glaucia Rodrigues Abreu
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Elenice Moreira Lemos
- Nucleus of Infectious Diseases, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Sonia Alves Gouvea
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
| | - Nazaré Souza Bissoli
- Department of Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil.
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11
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Efficacy of female rat models in translational cardiovascular aging research. J Aging Res 2014; 2014:153127. [PMID: 25610649 PMCID: PMC4294461 DOI: 10.1155/2014/153127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 12/05/2014] [Accepted: 12/05/2014] [Indexed: 01/11/2023] Open
Abstract
Cardiovascular disease is the leading cause of death in women in the United States. Aging is a primary risk factor for the development of cardiovascular disease as well as cardiovascular-related morbidity and mortality. Aging is a universal process that all humans undergo; however, research in aging is limited by cost and time constraints. Therefore, most research in aging has been done in primates and rodents; however it is unknown how well the effects of aging in rat models translate into humans. To compound the complication of aging gender has also been indicated as a risk factor for various cardiovascular diseases. This review addresses the systemic pathophysiology of the cardiovascular system associated with aging and gender for aging research with regard to the applicability of rat derived data for translational application to human aging.
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12
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Nekooeian AA, Khalili A, Khosravi MB. Effects of oleuropein in rats with simultaneous type 2 diabetes and renal hypertension: a study of antihypertensive mechanisms. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2014; 16:953-962. [PMID: 24954237 DOI: 10.1080/10286020.2014.924510] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 05/11/2014] [Indexed: 06/03/2023]
Abstract
The mechanism of oleuropein's antihypertensive effects was examined in rat model of simultaneous type 2 diabetes and renal hypertension (diabetic hypertensive). Five groups of male Sprague-Dawley rats including a control, a diabetic-hypertensive group receiving vehicle, and three diabetic-hypertensive groups receiving oleuropein at 20, 40, or 60 mg/kg/day were used. The duration of diabetes was 10 weeks; during the last 4 weeks of which, animals were hypertensive and received vehicle or oleuropein. Systolic blood pressure, glucose and malondialdehyde, heart rate, and maximal response to phenylephrine (PE) in the absence of nitro-L-arginine methyl ester (L-NAME) of oleuropein-treated groups were significantly lower than those of vehicle-treated group. Erythrocyte superoxide dismutase, maximal response to PE in the presence of L-NAME, and maximal response to acetylcholine (Ach) of oleuropein-treated groups were significantly higher than those of vehicle-treated group. The findings indicate that antihypertensive effects of oleuropein might be partly mediated by improving the release of nitric oxide, and antioxidant and sympathoplegic activities.
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Affiliation(s)
- Ali Akbar Nekooeian
- a Cardiovascular Pharmacology Research Lab, Department of Pharmacology , Medical school, Shiraz University of Medical Sciences , Shiraz 7134845794 , Iran
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13
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Wang D, Wang C, Wu X, Zheng W, Sandberg K, Ji H, Welch WJ, Wilcox CS. Endothelial dysfunction and enhanced contractility in microvessels from ovariectomized rats: roles of oxidative stress and perivascular adipose tissue. Hypertension 2014; 63:1063-9. [PMID: 24591333 DOI: 10.1161/hypertensionaha.113.02284] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ovarian hormone loss increases reactive oxidative species, endothelial dysfunction, and cardiovascular disease. Because perivascular adipose tissue (PVAT) regulates endothelial function, we hypothesized that reactive oxidative species in PVAT mediate adverse microvascular effects of ovarian hormone deficiency. Rats were ovariectomized or sham operated and given vehicle or tempol for 6 weeks. Mesenteric resistance arterioles from ovariectomized compared with sham-operated rats had dysfunctional responses to acetylcholine (ACh) including decreased ACh-induced endothelium-dependent relaxation (50±6% versus 72±2%) and endothelium-dependent relaxation factor (17±4% versus 37±2%) and increased endothelium-dependent contracting factor (27±5% versus 9±3%). OVX rat mesenteric arterioles had increased contractions to the thromboxane/prostanoid receptor agonist U-46 619 (58±3% versus 40±5%) and increased reactive oxidative species (tempo-9-AC fluorescence) with U-46 619 (0.65±0.17 versus 0.14±0.06 Δ unit) or ACh (0.49±0.09 versus 0.09±0.05 Δ unit) and increased p22(phox) protein expression (0.89±0.05 versus 0.18±0.04 Δ unit), whereas nitric oxide activity (DAF-FM [4-amino-5-methylamino-2',7'-difluorofluorescein diacetate] fluorescence) with ACh was reduced (0.39±0.1 versus 0.70±0.10 Δ unit). No differences were found in endothelium-dependent hyperpolarizing factor or contractile responses to phenylephrine. PVAT enhanced ACh-induced relaxation, endothelium-dependent relaxation factor, and nitric oxide only in sham-operated rats. Tempol prevented ovariectomy-induced endothelial dysfunction and restored the enhancing effects of PVAT on ACh-induced relaxation, endothelium-dependent relaxation factor, and nitric oxide in ovariectomized rat vessels, but both tempol and PVAT were required to normalize the enhanced U-46 619 contractions after ovariectomy. In conclusion, ovariectomy redirects endothelial responses from relaxation to contraction by reducing vascular nitric oxide, augmenting thromboxane/prostanoid receptor signaling, and attenuating the vasodilatory effects of PVAT, all of which were dependent on reactive oxidative species.
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Affiliation(s)
- Dan Wang
- Division of Nephrology and Hypertension, Georgetown University Medical Center, 6 PHC, Suite F6003, 3800 Reservoir Rd NW, Washington, DC 20007.
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14
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Caliman IF, Lamas AZ, Dalpiaz PLM, Medeiros ARS, Abreu GR, Gomes Figueiredo S, Nascimento Gusmão L, Uggere Andrade T, Souza Bissoli N. Endothelial relaxation mechanisms and oxidative stress are restored by atorvastatin therapy in ovariectomized rats. PLoS One 2013; 8:e80892. [PMID: 24278341 PMCID: PMC3836761 DOI: 10.1371/journal.pone.0080892] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/07/2013] [Indexed: 12/24/2022] Open
Abstract
The studies on hormone replacement therapy (HRT) in females with estrogen deficiency are not conclusive. Thus, non-estrogen therapies, such as atorvastatin (ATO), could be new strategies to substitute or complement HRT. This study evaluated the effects of ATO on mesenteric vascular bed (MVB) function from ovariectomized (OVX) female rats. Female rats were divided into control SHAM, OVX, and OVX treated with 17β-estradiol (EST) or ATO groups. The MVB reactivity was determined in organ chambers, vascular oxidative stress by dihydroethidine staining, and the expression of target proteins by western blot. The reduction in acetylcholine-induced relaxation in OVX rats was restored by ATO or EST treatment. The endothelium-dependent nitric oxide (NO) component was reduced in OVX rats, whereas the endothelium-derived hyperpolarizing factor (EDHF) component or prostanoids were not altered in the MVBs. Endothelial dysfunction in OVX rats was associated with oxidative stress, an up-regulation of iNOS and NADPH oxidase expression and a down-regulation of eNOS expression. Treatment with ATO or EST improved the NO component of the relaxation and normalized oxidative stress and the expression of those signaling pathways enzymes. Thus, the protective effect of ATO on endothelial dysfunction caused by estrogen deficiency highlights a significant therapeutic benefit for statins independent of its effects on cholesterol, thus providing evidence that non-estrogen therapy could be used for cardiovascular benefit in an estrogen-deficient state, such as menopause.
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Affiliation(s)
- Izabela Facco Caliman
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Aline Zandonadi Lamas
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | | | | | - Glaucia Rodrigues Abreu
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Suely Gomes Figueiredo
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Lara Nascimento Gusmão
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
| | - Tadeu Uggere Andrade
- Department of Pharmacy, University Center of Vila Velha, Vila Velha, Espirito Santo, Brazil
| | - Nazaré Souza Bissoli
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo, Brazil
- * E-mail:
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15
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Resveratrol attenuated smokeless tobacco–induced vascular and metabolic complications in ovariectomized rats. Menopause 2013; 20:869-76. [DOI: 10.1097/gme.0b013e31827fdda4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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16
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Cheang WS, Lam MY, Wong WT, Tian XY, Lau CW, Zhu Z, Yao X, Huang Y. Menthol relaxes rat aortae, mesenteric and coronary arteries by inhibiting calcium influx. Eur J Pharmacol 2013; 702:79-84. [PMID: 23380688 DOI: 10.1016/j.ejphar.2013.01.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/08/2013] [Accepted: 01/16/2013] [Indexed: 11/16/2022]
Abstract
Menthol, a naturally occurring compound in mint, is known to give cold sensation. However, previous findings about its pharmacological activity in blood vessels are full of paradox. The present study investigated the action of menthol on vascular reactivity in different arteries isolated from male Sprague-Dawley rats, e.g. aortae, main mesenteric arteries and coronary arteries. The arterial segments were suspended in organ bath or in wire myograph for measurement of isometric force. Menthol concentration-dependently relaxed all three arteries with similar relaxing sensitivity in arteries contracted by different contractors, KCl, U46619 (9,11-dideoxy-9α,11α-methanoepoxy Prostaglandin F2α) and phenylephrine. Menthol-induced relaxations were unaffected by nitric oxide synthase inhibitor L-NAME, soluble guanylyl cyclase inhibitor ODQ, or mechanical removal of endothelium. Menthol also concentration-dependently suppressed 60mM KCl-induced constriction and CaCl2-induced contraction in Ca(2+)-free K(+)-containing solution. Calcium fluorescent imaging using fluo-4 showed that 10 min-incubation with 1mM menthol inhibited 60mM KCl-induced Ca(2+) influx in rat aortic smooth muscle cell line A7r5 and vascular smooth muscle of coronary arteries. To conclude, menthol induces relaxation and inhibits contraction in rat aortae, mesenteric and coronary arteries primarily through inhibiting Ca(2+) influx via nifedipine-sensitive Ca(2+) channels in vascular smooth muscle.
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Affiliation(s)
- Wai San Cheang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
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17
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Cetinkaya Demir B, Uyar Y, Ozbilgin K, Köse C. Effect of raloxifene and atorvastatin in atherosclerotic process in ovariectomized rats. J Obstet Gynaecol Res 2012; 39:229-36. [PMID: 22845341 DOI: 10.1111/j.1447-0756.2012.01969.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The goal of this study was to investigate the combined effects of raloxifene and atorvastatin in aged ovariectomized rats during endothelial dysfunction and atherosclerotic process. MATERIAL AND METHODS This study was conducted on 28 Wistar albino female rats randomly divided into four groups. All groups were ovariectomized and one group was kept as the control group (OVX). For four weeks, the remaining three groups were treated with the statin atorvastatin (OVX+AV), the selective estrogen receptor modulator raloxifene (OVX+RL), and both atorvastatin and raloxifene (OVX+RL+AV), respectively. At the end of the treatment period, all rats were sacrificed and thoracic aortas excised, and endothelial cells were immunohistochemically stained for markers in the atherosclerotic process, such as inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α). RESULTS Compared to the ovariectomized group, the iNOS level was significantly increased in the OVX+RL group (P=0.002), but contrarily decreased in the groups OVX+AV (P=0.002) and OVX+RL+AV (P=0.002). eNOS levels in the groups OVX+AV (P=0.002) and OVX+RL+AV (P=0.002) were significantly lower than that in the OVX group. When compared to the OVX group, significant reductions in ET-1 and TNF-α levels were found in all treatment groups. A significant decrement in MCP-1 level was found in the OVX+AV group (P=0.002). CONCLUSION In aged ovariectomized rats, the administration of both raloxifene and atorvastatin significantly decreased the levels of ET-1 and TNF-α on endothelial cells. Combined treatment with these drugs shortly after menopause might play a potential preventive role in the early stages of atherosclerosis development.
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Affiliation(s)
- Bilge Cetinkaya Demir
- Department of Obstetrics and Gynecology, Faculty of Medicine, Uludag University, Bursa, Turkey.
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18
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Khalili A, Nekooeian AA, Khosravi MB, Fakher S. Simultaneous renal hypertension and type 2 diabetes exacerbate vascular endothelial dysfunction in rats. Int J Exp Pathol 2012; 93:210-7. [PMID: 22458508 DOI: 10.1111/j.1365-2613.2012.00811.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Despite the high rate of occurrence of both diabetes and hypertension in humans, the cardiovascular effects of the two conditions have not been investigated when they occur simultaneously. Thus this study examined the vascular effects of simultaneous type 2 diabetes and renal hypertension on endothelial function. Serum malondialdehyde and systolic blood pressure (SBP) were measured, glucose tolerance test (GTT) was performed, and concentration-response to phenylephrine (PE) in the absence and presence of nitro-l-arginine methyl ester (l-NAME), acetylcholine and sodium nitroprusside were conducted on aortic rings from diabetic control, type 2 diabetes, sham-operated, renal hypertensive, and simultaneous type 2 diabetes plus hypertension rats respectively. Hypertension, diabetes, and simultaneous diabetes and hypertension were associated with either increased or decreased maximal responses (E(max)) of PE dependent on in the presence or absence of l-NAME. There was also increased serum malondialdehyde and decreased E(max) of acetylcholine. Thus simultaneous hypertension and diabetes caused a greater decrease in E(max) of acetylcholine compared to that seen with either diabetes or hypertension alone higher than that seen in hypertension. The blood glucose during GTT was lower than that seen in diabetes groups. Thus simultaneous type 2 diabetes and the SBP was renal hypertension is associated with improved glucose tolerance, but with further deterioration of endothelial dysfunction compared with either condition alone.
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Affiliation(s)
- Azadeh Khalili
- Department of Pharmacology, Cardiovascular Pharmacology Research Center, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
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19
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Yin H, Shi ZG, Yu YS, Hu J, Wang R, Luan ZP, Guo DH. Protection against osteoporosis by statins is linked to a reduction of oxidative stress and restoration of nitric oxide formation in aged and ovariectomized rats. Eur J Pharmacol 2011; 674:200-6. [PMID: 22130356 DOI: 10.1016/j.ejphar.2011.11.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 11/10/2011] [Accepted: 11/10/2011] [Indexed: 12/21/2022]
Abstract
Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, have been used as a cholesterol-lowering drug to treat hyperlipidemia clinically. In recent years, accumulating evidence indicates the possible beneficial effect of statins on osteoporosis. The aim of present study was to investigate whether protection against osteoporosis by statins is linked to a reduction of oxidative stress and restoration of nitric oxide (NO) formation in aged and ovariectomized rats. The aged and ovariectomized rats were used as two models of osteoporosis for evaluation of the effect of simvastatin. It was found that simvastatin abated oxidative stress, increased NO production, subsequently attenuating osteoporosis in two models. In the in vitro studies, the protective effects against H(2)O(2)-induced cell injury were examined in the MG-63 human osteoblastic cells. It was found that simvastatin ameliorated H(2)O(2)-induced cell loss and cell apoptosis and increased alkaline phosphatase (ALP) activity in osteoblastic cells. Simvastatin abated oxidative stress through enhancing catalase, heme oxygenase 1 (HO-1), and superoxide dismutase (SOD) activity and suppressing NADPH oxidase activity. In addition, simvastatin raised nitric oxide synthase (NOS) activity and eNOS expression at basal condition; inhibited NOS activity and iNOS expression when treated with H(2)O(2). In conclusion, protection against osteoporosis by statins is linked to a reduction of oxidative stress and restoration of NO formation in aged and ovariectomized rats.
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Affiliation(s)
- Hong Yin
- Department of Pharmacy, Chinese People's Liberation Army General Hospital, Beijing, China
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20
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Chan YC, Leung FP, Tian XY, Yung LM, Lau CW, Chen ZY, Yao X, Laher I, Huang Y. Raloxifene improves vascular reactivity in pressurized septal coronary arteries of ovariectomized hamsters fed cholesterol diet. Pharmacol Res 2011; 65:182-8. [PMID: 22005391 DOI: 10.1016/j.phrs.2011.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2010] [Revised: 09/20/2011] [Accepted: 09/20/2011] [Indexed: 11/19/2022]
Abstract
Although vascular effects of selective estrogen receptor modulators (SERMs) have been extensively examined in conduit arteries, whether SERMs could favorably modulate myogenic response in resistance arteries is unknown. The impact of raloxifene therapy and cholesterol diet on myogenic constriction during estrogen deficiency is unresolved. This study investigated changes in vascular reactivity and myogenic responses in female ovariectomized (Ovx) hamsters fed high-cholesterol diet (HCD) with and without chronic treatment of raloxifene. Functional studies were performed on hamster septal coronary arteries cannulated in a pressure myograph. Acetylcholine (ACh)-induced dilatation was reduced in arteries from cholesterol-fed Ovx hamsters, but not in those from cholesterol-fed hamsters, while pressure-induced myogenic constriction was unaffected. Chronic treatment with raloxifene restored ACh-induced dilatation in cholesterol-fed Ovx hamsters. U46619-induced constriction was increased in arteries from cholesterol-fed Ovx hamsters but not from cholesterol-fed control hamsters, which was normalized by chronic raloxifene treatment. The pressure-diameter relationship is presented as normalized diameter versus intraluminal pressure, while the effect of ACh or U46619 is expressed as percentage of tone at 80 mm Hg. Two-way analysis of variance (ANOVA) followed by Bonferroni post-tests were used for statistical evaluation among different treatment groups. P<0.05 was taken as statistically significant. The present results show that chronic treatment with raloxifene could benefit myogenically active coronary arteries by (i) restoring ACh-induced dilatation and (ii) reducing U46619-induced constriction without affecting pressure-induced myogenic responses in cholesterol-fed hamsters during estrogen deficiency. If such benefit can be observed in humans, raloxifene and other SERMs may be useful to preserve endothelial function and curtail vascular hypersensitivity in resistance coronary arteries in post-menopausal women with hypercholesterolemia or hyperlipidemia, a lipid condition implicated in the pathogenesis of myocardial infarction.
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Affiliation(s)
- Yau-Chi Chan
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China.
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Yung LM, Wong WT, Tian XY, Leung FP, Yung LH, Chen ZY, Yao X, Lau CW, Huang Y. Inhibition of renin-angiotensin system reverses endothelial dysfunction and oxidative stress in estrogen deficient rats. PLoS One 2011; 6:e17437. [PMID: 21479266 PMCID: PMC3066200 DOI: 10.1371/journal.pone.0017437] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 02/04/2011] [Indexed: 11/18/2022] Open
Abstract
Background Estrogen deficiency increases the cardiovascular risks in postmenopausal women. Inhibition of the renin-angiotensin system (RAS) and associated oxidative stress confers a cardiovascular protection, but the role of RAS in estrogen deficiency-related vascular dysfunction is unclear. The present study investigates whether the up-regulation of RAS and associated oxidative stress contributes to the development of endothelial dysfunction during estrogen deficiency in ovariectomized (OVX) rats. Methodology/Principal Findings Adult female rats were ovariectomized with and without chronic treatment with valsartan and enalapril. Isometric force measurement was performed in isolated aortae. The expression of RAS components was determined by immunohistochemistry and Western blotting method while ROS accumulation in the vascular wall was evaluated by dihydroethidium fluorescence. Ovariectomy increased the expression of angiotensin-converting enzyme (ACE), angiotensin II type 1 receptor (AT1R), NAD(P)H oxidase, and nitrotyrosine in the rat aorta. An over-production of angiotensin II and ROS was accompanied by decreased phosphorylation of eNOS at Ser1177 in OVX rat aortae. These pathophysiological changes were closely coupled with increased oxidative stress and decreased nitric oxide bioavailability, culminating in markedly impaired endothelium-dependent relaxations. Furthermore, endothelial dysfunction and increased oxidative stress in aortae of OVX rats were inhibited or reversed by chronic RAS inhibition with enalapril or valsartan. Conclusions/Significance The novel findings highlight a significant therapeutic benefit of RAS blockade in the treatment of endothelial dysfunction-related vascular complications in postmenopausal states.
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Affiliation(s)
- Lai Ming Yung
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Tak Wong
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiao Yu Tian
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Fung Ping Leung
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Lai Hang Yung
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Zhen Yu Chen
- Department of Biochemistry, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Wai Lau
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
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22
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Camporez JPG, Akamine EH, Davel AP, Franci CR, Rossoni LV, Carvalho CRDO. Dehydroepiandrosterone protects against oxidative stress-induced endothelial dysfunction in ovariectomized rats. J Physiol 2011; 589:2585-96. [PMID: 21486789 DOI: 10.1113/jphysiol.2011.206078] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cardiovascular disease is less frequent in premenopausal women than in age-matched men or postmenopausal women. Moreover, the marked age-related decline in serum dehydroepiandrosterone (DHEA) level has been associated to cardiovascular disease. The aim of this study was to evaluate the effects of DHEA treatment on vascular function in ovariectomized rats. At 8 weeks of age, female Wistar rats were ovariectomized (OVX) or sham (SHAM) operated and 8 weeks after surgery both groups were treated with vehicle or DHEA (10mg kg⁻¹ week⁻¹) for 3 weeks. Aortic rings were used to evaluate the vasoconstrictor response to phenylephrine (PHE) and the relaxation responses to acetylcholine (ACh) and sodium nitroprusside (SNP). Tissue reactive oxygen species (ROS) production and SOD, NADPH oxidase and eNOS protein expression were analysed. PHE-induced contraction was increased in aortic rings from OVX compared to SHAM, associated with a reduction in NO bioavailability. Furthermore, the relaxation induced by ACh was reduced in arteries from OVX, while SNP relaxation did not change. The incubation of aortic rings with SOD or apocynin restored the enhanced PHE-contraction and the impaired ACh-relaxation only in OVX. DHEA treatment corrected the increased PHE contraction and the impaired ACh-induced relaxation observed in OVX by an increment in NO bioavailability and decrease in ROS production. Besides, DHEA treatment restores the reduced Cu/Zn-SOD protein expression and eNOS phosphorylation and the increased NADPH oxidase protein expression in the aorta of OVX rats. The present results suggest an important action of DHEA, improving endothelial function in OVX rats by acting as an antioxidant and enhancing the NO bioavailability.
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Affiliation(s)
- João Paulo Gabriel Camporez
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of S˜ao Paulo, SP, Brazil
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Chan YC, Leung FP, Wong WT, Tian XY, Yung LM, Lau CW, Tsang SY, Yao X, Chen ZY, Huang Y. Therapeutically relevant concentrations of raloxifene dilate pressurized rat resistance arteries via calcium-dependent endothelial nitric oxide synthase activation. Arterioscler Thromb Vasc Biol 2010; 30:992-9. [PMID: 20185791 DOI: 10.1161/atvbaha.110.203935] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Selective estrogen receptor modulators (SERMs) inhibit constriction of mammalian conduit arteries. However, it is unknown whether SERMs at therapeutically achievable concentrations could reduce vascular tone in resistance arteries. The present study aimed to examine roles of Ca(2+) influx in endothelium and endothelial nitric oxide synthase (eNOS) activation in dilatations induced by raloxifene, a second-generation SERM in myogenically active arteries. METHODS AND RESULTS Small mesenteric arteries from Sprague-Dawley rats were isolated and mounted in a pressure myograph for measurement of changes in vessel diameter. [Ca(2+)](i) images on native endothelial cells of intact arteries were determined by the fluorescence imaging technique, and phosphorylation of eNOS was assayed by Western blotting. Raloxifene (0.3 to 10 nmol/L) produced dilatations on established steady myogenic constriction. Female rat arteries dilated significantly more in response to raloxifene than male arteries. Raloxifene-induced dilatations of female arteries were blunted by N(G)-nitro-l-arginine methyl ester but unaffected by 1400W, charybdotoxin plus apamin, wortmannin, or LY294002. Raloxifene (3 nmol/L) triggered rises in endothelial cell [Ca(2+)](i) and increased eNOS phosphorylation at Ser1177. Both effects were greater in arteries from female rats than in arteries from male rats. Increases in endothelial cell [Ca(2+)](i) and in eNOS phosphorylation were prevented by removal of extracellular Ca(2+) ions. Finally, ICI 182,780 did not affect the raloxifene-stimulated rise in endothelial cell [Ca(2+)](i), eNOS phosphorylation, and vasodilatations. Chronic raloxifene treatment reduced myogenic constriction in arteries from female but not male rats. CONCLUSION Raloxifene at therapeutically relevant concentrations inhibits myogenic constriction by an NO-dependent mechanism that causally involves the elevated [Ca(2+)](i) in endothelial cells and subsequent eNOS activation. Raloxifene dilates resistance arteries more effectively in female rats, indicating its significant gender-related action on endothelial cells in microcirculation.
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Affiliation(s)
- Yau Chi Chan
- Institute of Vascular Medicine, Hong Kong, China
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Abstract
The endothelium can evoke relaxations (dilatations) of the underlying vascular smooth muscle, by releasing vasodilator substances. The best characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO). The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDHF-mediated responses). Endothelium-dependent relaxations involve both pertussis toxin-sensitive G(i) (e.g. responses to serotonin and thrombin) and pertussis toxin-insensitive G(q) (e.g. adenosine diphosphate and bradykinin) coupling proteins. The release of NO by the endothelial cell can be up-regulated (e.g. by oestrogens, exercise and dietary factors) and down-regulated (e.g. oxidative stress, smoking and oxidized low-density lipoproteins). It is reduced in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively loose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and causing endothelium-dependent hyperpolarizations), endothelial cells also can evoke contraction (constriction) of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factor (EDCF). Most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells. EDCF-mediated responses are exacerbated when the production of NO is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive patients.
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Affiliation(s)
- P M Vanhoutte
- Department of Pharmacology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
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Wong CM, Yung LM, Leung FP, Tsang SY, Au CL, Chen ZY, Yao X, Cheng CHK, Lau CW, Gollasch M, Huang Y. Raloxifene protects endothelial cell function against oxidative stress. Br J Pharmacol 2008; 155:326-34. [PMID: 18574454 DOI: 10.1038/bjp.2008.262] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Maintaining a delicate balance between the generation of nitric oxide (NO) and removal of reactive oxygen species (ROS) within the vascular wall is crucial to the physiological regulation of vascular tone. Increased production of ROS reduces the effect and/or bioavailability of NO, leading to an impaired endothelial function. This study tested the hypothesis that raloxifene, a selective oestrogen receptor modulator, can prevent endothelial dysfunction under oxidative stress. EXPERIMENTAL APPROACH Changes in isometric tension were measured in rat aortic rings. The content of cyclic GMP in aortic tissue was determined by radioimmunoassay. Phosphorylation of endothelial NOS (eNOS) and Akt was assayed by Western blot analysis. KEY RESULTS In rings with endothelium, ACh-induced relaxations were attenuated by a ROS-generating reaction (hypoxanthine plus xanthine oxidase, HXXO). The impaired relaxations were ameliorated by acute treatment with raloxifene. HXXO suppressed the ACh-stimulated increase in cyclic GMP levels; this effect was antagonized by raloxifene. The improved endothelial function by raloxifene was abolished by ICI 182,780, and by wortmannin or LY294002. Raloxifene also protected endothelial cell function against H2O2. Raloxifene increased the phosphorylation of eNOS at Ser-1177 and Akt at Ser-473; this effect was blocked by ICI 182,780. Finally, raloxifene was not directly involved in scavenging ROS, and neither inhibited the activity of xanthine oxidase nor stimulated that of superoxide dismutase. CONCLUSION AND IMPLICATIONS Raloxifene is effective against oxidative stress-induced endothelial dysfunction in vitro through an ICI 182,780-sensitive mechanism that involves the increased phosphorylation and activity of Akt and eNOS in rat aortae.
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Affiliation(s)
- C M Wong
- Institute of Vascular Medicine and Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
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Abu-Fanne R, Brzezinski A, Golomb M, Grad E, Foldes AJ, Shufaro Y, Varon D, Brill A, Lotan C, Danenberg HD. Effects of estradiol and raloxifene on arterial thrombosis in ovariectomized mice. Menopause 2008; 15:98-104. [PMID: 17549036 DOI: 10.1097/gme.0b013e318054e2ab] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The effects of estrogen and selective estrogen receptor modulators (eg, raloxifene) on arterial thrombosis are not well defined. This study assessed the manner and mechanism by which estrogen and raloxifene affect homeostatic pathways in ovariectomized mice after acute arterial injury. DESIGN Female mice (3 weeks old) underwent ovariectomy or sham operation. Five days after surgery, mice were assigned to treatment with estradiol (5.3 nmol/kg), raloxifene (2.7 micromol/kg), or placebo (n = 10-12/group). The biological effects of both treatments were assessed by measurements of bone mass and the degree of uterine atrophy. After 4 months of therapy, carotid artery thrombosis was induced by photochemical injury, and the time to vascular occlusion was measured. RESULTS Both treatments increased bone mineral density (4.1%-7.85%). Reversal of macroscopic uterine atrophy was observed only in estrogen-treated mice. Ovariectomized mice had a shorter time to occlusion compared with sham-operated mice (70.8 +/- 7.4 vs 103 +/- 11.3 min), suggesting accelerated thrombosis. Both estradiol and raloxifene significantly inhibited intra-arterial thrombosis in ovariectomized mice, prolonging the time to occlusion to 136.33 +/- 13.5 and 141.43 +/- 9.26 min, respectively. Cyclooxygenase-2 levels in the lung tissue were significantly increased by both raloxifene and estradiol with endothelial nitric oxide synthase expression being unaltered. Platelet adhesion (measured by surface coverage under a shear rate of 1,800 s for 2 min) was significantly reduced in ovariectomized animals, being 4.63% +/- 1.47%, 5.78% +/- 1.58%, and 10.04% +/- 1.33% for raloxifene, estradiol, and placebo, respectively. CONCLUSIONS Ovariectomy amplifies thrombosis. We found that 4 months of treatment with both estradiol and raloxifene attenuates intravascular thrombosis. The antithrombotic effect was accompanied by increased expression of cyclooxygenase-2 and suppression of platelet surface adhesion.
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Affiliation(s)
- Rami Abu-Fanne
- Cardiovascular Research Center, Hadassah Hebrew University Medical Center, Kiryat Hadassah, Jerusalem, Israel
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Leung FP, Tsang SY, Wong CM, Yung LM, Chan YC, Leung HS, Yao X, Huang Y. Raloxifene, tamoxifen and vascular tone. Clin Exp Pharmacol Physiol 2007; 34:809-13. [PMID: 17600563 DOI: 10.1111/j.1440-1681.2007.04684.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Oestrogen deficiency causes progressive reduction in endothelial function. Despite the benefits of hormone-replacement therapy (HRT) evident in earlier epidemiological studies, recent randomized trials of HRT for the prevention of heart disease found no overall benefit. Instead, HRT users had higher incidences of stroke and heart attack. Most women discontinue HRT because of its many side-effects and/or the increased risk of breast and uterine cancer. This has contributed to the development of selective oestrogen receptor modulators (SERMs), such as tamoxifen and raloxifene, as alternative oestrogenic agents. 2. A SERM is a molecule that binds with high affinity to oestrogen receptors but has tissue-specific effects distinct from oestrogen, acting as an oestrogen agonist in some tissues and as an antagonist in others. Clinical and animal studies suggest multiple cardiovascular effects of SERMs. For example, raloxifene lowers serum levels of cholesterol and homocysteine, attenuates oxidation of low-density lipoprotein, inhibits endothelial-leucocyte interaction, improves endothelial function and reduces vascular smooth muscle tone. 3. Available evidence suggests that raloxifene and tamoxifen are capable of acting directly on both endothelial cells and the underlying vascular smooth muscle cells and cause a multitude of favourable modifications of the vascular wall, which jointly contribute to improved local blood flow. The outcome of the Raloxifene Use for the Heart (RUTH) trial will determine whether raloxifene, currently approved for the treatment of post-menopausal osteoporosis, could substitute for HRT in alleviating cardiovascular symptoms in post-menopausal women.
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Affiliation(s)
- Fung Ping Leung
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
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Chan YC, Leung FP, Yao X, Lau CW, Vanhoutte PM, Huang Y. Raloxifene Modulates Pulmonary Vascular Reactivity in Spontaneously Hypertensive Rats. J Cardiovasc Pharmacol 2007; 49:355-61. [PMID: 17577099 DOI: 10.1097/fjc.0b013e318046f329] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Selective estrogen receptor modulators (SERMs) reduce vascular tone in the systemic circulation. Their effects on the pulmonary circulation are unknown. The present study examined the effect of oral treatment with raloxifene (a second-generation SERM) on vasomotor reactivity in pulmonary arteries from normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Pulmonary arterial rings were suspended in a multi-channel myograph, and changes in isometric tension were measured. WKY rings constricted less to U46619 than SHR rings, and the difference was eliminated after chronic treatment with raloxifene. More contraction to U46619 was obtained after inhibition of nitric oxide synthase (NOS) by L-NAME (as an index of basal NO release) in raloxifene-treated than in control SHR rings. Less U46619-induced contraction after raloxifene treatment occurred only in SHR rings with endothelium, and this effect was abolished upon removal of the endothelium. Raloxifene treatment did not enhance the contribution of basal NO to U46619-induced constriction in WKY rings. Raloxifene treatment did not modify endothelium-dependent relaxation to acetylcholine and endothelium-independent relaxation to nifedipine. The reduced relaxing sensitivity to sodium nitroprusside (SNP) in SHR rings was normalized by raloxifene treatment. Raloxifene treatment reduced CaCl2-induced tone in SHR but not in WKY rings. The results show that chronic treatment with raloxifene could improve pulmonary vascular function in hypertensive animals by (1) increasing basal NO release, (2) reducing vascular smooth muscle tone, and (3) improving the effect of NO on vascular smooth muscle in SHR. In contrast, raloxifene has little effect on vascular reactivity in pulmonary arteries from normotensive WKY rats.
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Affiliation(s)
- Yau-Chi Chan
- Li Ka Shing Institute of Health Sciences and Department of Physiology, Chinese University of Hong Kong, P.R. China
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