1
|
Effects and Mechanisms of Traditional Chinese Herbal Medicine in the Treatment of Ischemic Cardiomyopathy. Pharmacol Res 2020; 151:104488. [DOI: 10.1016/j.phrs.2019.104488] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/28/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
|
2
|
Ragone MI, Bayley M, Colareda GA, Bonazzola P, Consolini AE. Cardioprotective Mechanisms of Hypothyroidism on Ischemia/Reperfusion in Rats and Effects of Carvedilol: Energetic Study. J Cardiovasc Pharmacol Ther 2019; 25:72-85. [DOI: 10.1177/1074248419872957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hypothyroidism is considered a cardiac risk factor, but there is controversial evidence about its effects on coronary disease. The aim of this work was to evaluate the influence of hypothyroidism in rat hearts exposed to 2 degrees of stunning due to ischemia and reperfusion (I/R) as well as the underlying mechanisms. Hypothyroid (HypoT) rats were obtained by drinking 0.02% methimazole during 15 days. Isolated hearts were perfused and introduced in a flow calorimeter to measure contractile performance (P), total heat rate (Ht), and muscle economy (P/Ht). Hearts were exposed to 2 models of I/R, moderate and severe (respectively 20 or 30 minutes I/45 minutes R). Moreover, free cytosolic and mitochondrial calcium changes were measured by confocal fluorometry on cardiomyocytes. Comparison to euthyroid (EuT) hearts was done. Hypothyroidism was cardioprotective, but HypoT hearts were more sensitive than EuT hearts to the preischemic blockade of mitochondrial transporters mNCX and mKATPchannels. Moreover, the postischemic recovery of P and P/Ht in HypoT hearts was strongly reduced by inhibition of the cellular pathways of PI3K/Akt and protein kinase C (PKC), and it was increased by nitric oxide synthase (NOS) inhibition. However, physiological concentrations of adrenaline reduced the cardioprotection of HypoT, but oral treatment with 20 mg/kg/day carvedilol prevented it. Results show that hypothyroidism reduces the mitochondrial Ca2+overload during I/R by mKATPchannel activation and Ca2+extrusion through mNCX, while the PI3K/Akt and PKC pathways are involved in that cardioprotection. Contrarily, NOS activation and adrenaline blunt such cardioprotection, but carvedilol prevented the adrenergic dysfunction. These results would explain why hypothyroidism is a clinical risk factor in angor patients under adrenergic exacerbation but reduced the incidence of acute episodes of coronary syndrome in hospitalized patients. Results suggest that a treatment with carvedilol could be a potential therapeutic agent to prevent cardiac postischemic dysfunction in hypothyroid patients.
Collapse
Affiliation(s)
- María Inés Ragone
- Cátedra de Farmacología, Grupo de Farmacología Experimental y Energética Cardíaca, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Matías Bayley
- Cátedra de Farmacología, Grupo de Farmacología Experimental y Energética Cardíaca, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Germán A. Colareda
- Cátedra de Farmacología, Grupo de Farmacología Experimental y Energética Cardíaca, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Patricia Bonazzola
- Instituto de Investigaciones Cardiológicas, Facultad de Medicina, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Alicia E. Consolini
- Cátedra de Farmacología, Grupo de Farmacología Experimental y Energética Cardíaca, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| |
Collapse
|
3
|
Sivasinprasasn S, Shinlapawittayatorn K, Chattipakorn SC, Chattipakorn N. Estrogenic Impact on Cardiac Ischemic/Reperfusion Injury. J Cardiovasc Transl Res 2016; 9:23-39. [PMID: 26786980 DOI: 10.1007/s12265-016-9675-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/07/2016] [Indexed: 11/29/2022]
Abstract
The increase in cardiovascular disease and metabolic syndrome incidence following the onset of menopause has highlighted the role of estrogen as a cardiometabolic protective agent. Specifically regarding the heart, estrogen induced an improvement in cardiac function, preserved calcium homeostasis, and inhibited the mitochondrial apoptotic pathway. The beneficial effects of estrogen in relation to cardiac ischemia/reperfusion (I/R) injury, such as reduced infarction and ameliorated post-ischemic recovery, have also been shown. Nevertheless, controversial findings exist and estrogen therapy is reported to be related to a higher rate of thromboembolic events and atrial fibrillation in post-menopausal women. Therefore, greater clarification is needed to evaluate the exact potential of estrogen use in cases of cardiac I/R injury. This article reviews the effects of estrogen, in both acute and chronic treatment, and collates the studies with regard to their in vivo, in vitro, or clinical trial settings in cases of cardiac I/R injury and myocardial infarction.
Collapse
Affiliation(s)
- Sivaporn Sivasinprasasn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.,Cardiac Electrophysiology unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,School of Medicine, Mae Fah Luang University, Chiang Rai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Krekwit Shinlapawittayatorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.,Cardiac Electrophysiology unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.,Department of Oral Biology and Diagnostic Science, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand. .,Cardiac Electrophysiology unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand. .,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.
| |
Collapse
|
4
|
Chae YJ, Kim DH, Lee HJ, Sung KW, Kwon OJ, Hahn SJ. Raloxifene inhibits cloned Kv4.3 channels in an estrogen receptor-independent manner. Pflugers Arch 2014; 467:1663-76. [PMID: 25231973 DOI: 10.1007/s00424-014-1602-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 12/16/2022]
Abstract
Raloxifene is widely used for the treatment and prevention of postmenopausal osteoporosis. We examined the effects of raloxifene on the Kv4.3 currents expressed in Chinese hamster ovary (CHO) cells using the whole-cell patch-clamp technique and on the long-term modulation of Kv4.3 messenger RNA (mRNA) by real-time PCR analysis. Raloxifene decreased the Kv4.3 currents with an IC50 of 2.0 μM and accelerated the inactivation and activation kinetics in a concentration-dependent manner. The inhibitory effects of raloxifene on Kv4.3 were time-dependent: the association and dissociation rate constants for raloxifene were 9.5 μM(-1) s(-1) and 23.0 s(-1), respectively. The inhibition by raloxifene was voltage-dependent (δ = 0.13). Raloxifene shifted the steady-state inactivation curves in a hyperpolarizing direction and accelerated the closed-state inactivation of Kv4.3. Raloxifene slowed the time course of recovery from inactivation, thus producing a use-dependent inhibition of Kv4.3. β-Estradiol and tamoxifen had little effect on Kv4.3. A preincubation of ICI 182,780, an estrogen receptor antagonist, for 1 h had no effect on the inhibitory effect of raloxifene on Kv4.3. The metabolites of raloxifene, raloxifene-4'-glucuronide and raloxifene-6'-glucuronide, had little or no effect on Kv4.3. Coexpression of KChIP2 subunits did not alter the drug potency and steady-state inactivation of Kv4.3 channels. Long-term exposure to raloxifene (24 h) significantly decreased the expression level of Kv4.3 mRNA. This effect was not abolished by the coincubation with ICI 182,780. Raloxifene inhibited Kv4.3 channels by interacting with their open state during depolarization and with the closed state at subthreshold potentials. This effect was not mediated via an estrogen receptor.
Collapse
Affiliation(s)
- Yun Ju Chae
- Department of Physiology, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 137-701, South Korea
| | | | | | | | | | | |
Collapse
|
5
|
Raloxifene upregulated mesangial cell MMP-2 activity via ER-β through transcriptional regulation. Cell Biochem Biophys 2014; 67:607-13. [PMID: 23471663 DOI: 10.1007/s12013-013-9548-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Raloxifene, a second-generation selective estrogen receptor modulator, exerts estrogen-like effects in specific tissues. In this present study, we examined the effect of raloxifene on mesangial cell matrix metalloproteinase-2 (MMP-2) activity in streptozotocin-induced diabetic mice. Raloxifene increased the MMP-2 level in a dose-dependent and receptor-mediated manner. An antibody against estrogen receptor-β (ER-β) blocked the effect of raloxifene on MMP-2 expression, suggesting that the effect of raloxifene on MMP-2 activity was mediated by ER-β. In addition, the transcription factor AP-2, that plays an important role in MMP-2 gene transcription, was overexpressed under raloxifene simulation. The effect of MMP-2 was blocked by a selective inhibitor of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway, PD98059. Our results suggested that raloxifene-induced MMP-2 activity increases function through ERK/MAPK signaling via AP-2. In addition, we also found that the effect of raloxifene on MMP-2 expression was mediated via its binding to ER-β. However, at this stage of our investigation, (i) we could only show that both the binding to ER-β and the activation of the ERK/MAPK pathway impacted MMP-2 expression and (ii) we were unable to establish a relationship between ER-β binding and ERK/MAPK pathway activation.
Collapse
|
6
|
Li J, Zhang H, Zhang C. Role of inflammation in the regulation of coronary blood flow in ischemia and reperfusion: mechanisms and therapeutic implications. J Mol Cell Cardiol 2011; 52:865-72. [PMID: 21924274 DOI: 10.1016/j.yjmcc.2011.08.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 08/14/2011] [Accepted: 08/29/2011] [Indexed: 01/10/2023]
Abstract
A multitude of factors, including increased coronary vascular resistance and dysregulated coronary microcirculatory function, contribute to the impairment of coronary blood flow (CBF) regulation and the pathogenesis of myocardial ischemia/reperfusion (I/R) injury. CBF is primarily determined by coronary vascular resistance, which is affected by the balance between various vasodilators and vasoconstrictors. Myocardial I/R causes reduced production of endogenous vasodilators, such as nitric oxide (NO), leaving unopposed vasoconstriction that is caused mainly by continued presence of endothelin-1 (ET-1) and serotonin (5-HT); this imbalance in turn enhances vascular tone, triggers inflammatory response, decreases CBF and exacerbates reperfusion injury. Various inflammatory cytokines participate in the regulation of coronary vasomotor function by affecting the balance between vasodilators and vasoconstrictors. In addition to the enhanced coronary vasoconstriction, coronary microembolization, inflammatory cell infiltration and post-ischemic hyperpermeability contribute to the impairment of coronary microcirculatory function and myocardial perfusion during I/R. Ongoing research examining the role of inflammation in the regulation of CBF and coronary microcirculatory function in myocardial I/R is expected to yield new insights that will lead to therapies for ameliorating the vascular inflammatory response in coronary artery diseases (CADs) in the clinical setting. This article is part of a Special Issue entitled "Coronary Blood Flow".
Collapse
Affiliation(s)
- Jun Li
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, United States
| | | | | |
Collapse
|
7
|
Meyer MR, Prossnitz ER, Barton M. The G protein-coupled estrogen receptor GPER/GPR30 as a regulator of cardiovascular function. Vascul Pharmacol 2011; 55:17-25. [PMID: 21742056 PMCID: PMC3216677 DOI: 10.1016/j.vph.2011.06.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/19/2011] [Accepted: 06/25/2011] [Indexed: 12/29/2022]
Abstract
Endogenous estrogens are important regulators of cardiovascular homeostasis in premenopausal women and delay the development of hypertension and coronary artery disease. These hormones act via three different estrogen receptors affecting both gene transcription and rapid signaling pathways in a complex interplay. In addition to the classical estrogen receptors ERα and ERβ, which are known mediators of estrogen-dependent vascular effects, a G protein-coupled estrogen receptor termed GPER that is expressed in the cardiovascular system has recently been identified. Endogenous human 17β-estradiol, selective estrogen receptor modulators (SERMs) including tamoxifen and raloxifene, and selective estrogen receptor downregulators (SERDs) such as ICI 182,780 are all agonists of GPER, which has been implicated in the regulation of vasomotor tone and protection from myocardial ischemia/reperfusion injury. As a result, understanding the individual role of ERα, ERβ, and GPER in cardiovascular function has become increasingly complex. With accumulating evidence that GPER is responsible for a variety of beneficial cardiovascular effects of estrogens, this receptor may represent a novel target to develop effective strategies for the treatment of cardiovascular diseases by tissue-specific, selective activation of estrogen-dependent molecular pathways devoid of side effects seen with conventional hormone therapy.
Collapse
Affiliation(s)
- Matthias R. Meyer
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Eric R. Prossnitz
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Matthias Barton
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland
| |
Collapse
|
8
|
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.
Collapse
Affiliation(s)
- Yau Chi Chan
- Institute of Vascular Medicine, Hong Kong, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Gürses L, Seçkin H, Simşek S, Senel OO, Yigitkanli K, Oztürk E, Beşalti O, Belen D, Bavbek M. Effects of raloxifene on cerebral vasospasm after experimental Subarachnoid Hemorrhage in rabbits. ACTA ACUST UNITED AC 2009; 72:490-4; discussion 494-5. [PMID: 19147193 DOI: 10.1016/j.surneu.2008.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Revised: 10/14/2008] [Accepted: 11/19/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasospasm in a rabbit model of SAH. METHODS Thirty-four New Zealand white rabbits were allocated into 3 groups randomly. Subarachnoid hemorrhage was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH [n = 12]), (2) SAH only (n = 12), and (3) SAH plus RLX (n = 10). Basilar artery lumen areas and arterial wall thickness were measured to assess vasospams in all groups. RESULTS There was a statistically significant difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements of the control and SAH-only groups (P < .05). The difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements in the RLX-treated group was statistically significant (P < .05). The difference between the SAH group and the SAH + RLX group was also statistically significant (P < .05). CONCLUSIONS These findings demonstrate that RLX has marked vasodilatatory effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this SERM drug could be used as possible anti-vasospastic agent in patients without major adverse effects.
Collapse
Affiliation(s)
- Levent Gürses
- Ministry of Health, Dişkapi Educational and Research Hospital, 2nd Neurosurgery Clinic, Ankara, Turkey
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Liu H, Jin MW, Xiang JZ, Huang Y, Sun HY, Chiu SW, Lau CP, Li GR. Raloxifene inhibits transient outward and ultra-rapid delayed rectifier potassium currents in human atrial myocytes. Eur J Pharmacol 2007; 563:61-8. [PMID: 17337266 DOI: 10.1016/j.ejphar.2007.01.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 01/22/2007] [Accepted: 01/24/2007] [Indexed: 10/23/2022]
Abstract
The selective estrogen receptor modulator raloxifene is widely used in the treatment of postmenopausal osteoporosis, and has cardioprotective properties. However, effects of raloxifene on cardiac ion channels are unclear. The present study was designed to investigate the effects of raloxifene and beta-estradiol on transient outward and ultra-rapid delayed rectifier potassium currents (Ito1 and IKur) in human atrial myocytes with a whole cell patch-clamp technique. Ito1 was inhibited by raloxifene in a concentration-dependent manner with an IC50 of 0.9 microM. Raloxifene at 1 microM decreased Ito1 by 40.2+/-1.9% (at +50 mV, n=14, P<0.01 vs control). Time-dependent recovery from inactivation was slowed, and time to peak and time-dependent inactivation of Ito1 were significantly accelerated, while steady-state voltage dependent activation and inactivation of Ito1 were not affected by raloxifene. In addition, raloxifene remarkably suppressed IKur (IC50=0.7 microM). Raloxifene at 1 microM decreased IKur by 57.3+/-3.3% (at +50 mV, n=10, P<0.01 vs control). However, beta-estradiol inhibited Ito1 (IC50=10.3 microM) without affecting IKur. The inhibitory effects of raloxifene and beta-estradiol on Ito1 and/or IKur were unaffected by the estrogen receptor antagonist ICI 182,780. Our results indicate that raloxifene directly inhibits the human atrial repolarization potassium currents Ito1 and IKur. Whether raloxifene is beneficial for supraventricular arrhythmias remains to be studied.
Collapse
Affiliation(s)
- Hui Liu
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Moritz A, Radtke OA, Gust R, Glusa E, Pertz HH. Characterisation of the relaxant response to raloxifene in porcine coronary arteries. Eur J Pharmacol 2006; 545:153-60. [PMID: 16859668 DOI: 10.1016/j.ejphar.2006.06.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Revised: 06/20/2006] [Accepted: 06/22/2006] [Indexed: 11/18/2022]
Abstract
The present study characterises the vasorelaxant response to raloxifene in isolated rings of porcine coronary artery. Tissues precontracted either with KCl (30 mM) or prostaglandin F(2alpha) (PGF(2alpha); 3 microM) were concentration-dependently relaxed by raloxifene (0.1-10 microM). Relaxation was not inhibited by the estrogen receptor antagonist 7alpha-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]-estra-1,3,5(10)-triene-3,17beta-diol (ICI 182,780; 1 microM). Preincubation with raloxifene (1-3 microM) caused an inhibition of the KCl or PGF(2alpha)-induced contraction. The effects of raloxifene were independent of the endothelium. The relaxant response to raloxifene was slow in the onset and could not be reversed after repeated washings. Raloxifene did not affect Ca(2+) release from intracellular stores since it failed to inhibit a transient contraction induced by caffeine (10 mM). Raloxifene-induced relaxation was not influenced by the intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM; 10-20 microM). Calcium-induced contractions in Ca(2+)-free high K(+) (60 mM) depolarising medium were concentration-dependently inhibited by raloxifene (0.3-3 microM). If arterial rings were incubated with the L-type Ca(2+) channel activator (S)-(-)-1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-3-pyridine carboxylic acid methyl ester ((S)-(-)-Bay K 8644; 0.1 microM), cumulative concentration-response curves to Ca(2+) were shifted to the left. Raloxifene (0.3-3 microM) inhibited the effect of (S)-(-)-Bay K 8644 in a concentration-dependent manner. 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole (SB 203580; 10 microM), an inhibitor of p38 mitogen-activated protein kinase (MAPK), diminished raloxifene-induced relaxation in endothelium-denuded arterial rings. Western blot analysis demonstrated that raloxifene stimulated p38 MAPK. It is concluded that raloxifene has an inhibitory effect on voltage-gated and receptor-operated L-type Ca(2+) channels in porcine coronary arteries, thus inducing vascular relaxation independent of the endothelium. p38 MAPK is, at least in part, involved in the relaxant response to raloxifene.
Collapse
Affiliation(s)
- Alkje Moritz
- Free University of Berlin, Institute of Pharmacy, Königin-Luise-Str. 2+4, 14195 Berlin, Germany
| | | | | | | | | |
Collapse
|
12
|
Zoma WD, Baker RS, Mershon JL, Clark KE. Hemodynamic effects of acute and repeated exposure to raloxifene in ovariectomized sheep. Am J Physiol Heart Circ Physiol 2006; 291:H1216-25. [PMID: 16517945 DOI: 10.1152/ajpheart.00666.2005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesize that administration of acute and daily doses of raloxifene will have significant effects on ovine coronary and uterine hemodynamics and that these changes are estrogen receptor dependent. Eleven ovariectomized sheep were instrumented to measure mean arterial pressure, heart rate (HR), cardiac output (CO), and coronary (CBF) and uterine artery blood flows (UBF). A dose-response curve was generated for raloxifene (1, 3, and 10 microg/kg) and compared with a standard dose of estradiol-17beta (1 microg/kg) given intravenously. In a second group of animals, raloxifene (10 microg.kg-1.day-1) was administered intravenously for 14 consecutive days, and cardiovascular responses were compared with a group of animals administered estradiol-17beta (10 microg/kg) daily for the same period. To determine whether raloxifene-related vascular responses were estrogen receptor (ER) mediated, the animals were pretreated with estrogen antagonist ICI-182,780 given intravenously. Finally, RT-PCR was preformed to determine the presence of ERalpha and ERbeta mRNA in ovine coronary and uterine vessels. Raloxifene increased CBF and UBF dose dependently with a parallel decrease in the associated vascular resistances. Acute cardiovascular responses to daily doses of raloxifene and estradiol-17beta were sustainable. In contrast to estradiol-17beta, which significantly increases CO by increasing HR but not stroke volume, raloxifene significantly increased stroke volume without a significant parallel increase in HR. ICI-182,780 abolished raloxifene-induced hemodynamic responses, and ERalpha and ERbeta mRNA are present in both ovine coronary and uterine vessels. Hence, the hemodynamic effects of raloxifene are dose dependent, sustainable, and estrogen receptor mediated.
Collapse
Affiliation(s)
- Willie D Zoma
- Department of Obstetrics and Gynecology, P.O. Box 670526, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0526, USA
| | | | | | | |
Collapse
|
13
|
Sitnick M, Foley AM, Brown M, Spangenburg EE. Ovariectomy prevents the recovery of atrophied gastrocnemius skeletal muscle mass. J Appl Physiol (1985) 2006; 100:286-93. [PMID: 16150841 DOI: 10.1152/japplphysiol.00869.2005] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The recovery of atrophied muscle mass in animals is thought to be dependent on a number of factors including hormones, cytokines, and/or growth factor expression. The Akt/mammalian target of rapamycin (mTOR) signaling pathway is believed to be activated by these various factors, resulting in skeletal muscle growth through the initiation of protein synthesis. It was hypothesized that surgical removal of the ovaries (Ovx) may alter activation of the Akt/mTOR signaling pathway, a mechanism necessary for muscle regrowth. To test this, 36 Sprague-Dawley rats underwent Ovx or sham surgeries. A portion of the animals were then subjected to hindlimb unloading (HLU) for 28 days. After HLU, one group of Sham and Ovx rats underwent a 14-day recovery period in which the animals were allowed free cage ambulation. The HLU animals demonstrated ∼21–27% reduction in medial gastrocnemius muscle mass irrespective of whether the ovaries were intact or not. The Sham animals that were reloaded recovered their atrophied muscle mass; however, the Ovx group failed to recover any of the atrophied muscle mass with reloading. The failure to recover muscle mass in the Ovx group was associated with reduced phosphorylation levels of both Akt and p70s6k, whereas in the Sham recovery animals no reductions were found in Akt phosphorylation and significant increases in p70s6k activation were detected. Finally, no differences were detected in mTOR phosphorylation in any of Sham or Ovx groups. These results suggest that ovariectomy surgeries could be detrimental to the recovery of atrophied muscle mass.
Collapse
Affiliation(s)
- Mitchell Sitnick
- Molecular, Cellular, and Integrative Physiology Graduate Group, University of California, Davis, One Shields Ave., Davis, California 95616, USA
| | | | | | | |
Collapse
|
14
|
Leung FP, Yao X, Lau CW, Ko WH, Lu L, Huang Y. Raloxifene relaxes rat intrarenal arteries by inhibiting Ca2+ influx. Am J Physiol Renal Physiol 2005; 289:F137-44. [PMID: 15713909 DOI: 10.1152/ajprenal.00353.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Raloxifene may confer vascular benefits without causing estrogen-related side effects. However, its action on renal vascular circulation is unknown. This study aimed to examine the sex difference and roles of the endothelium and Ca2+ channels in rat renovascular relaxation to raloxifene. On isolated intralobar renal artery rings mounted in a myograph and contracted by U-46619, concentration-relaxation curves were constructed for raloxifene and contractions to CaCl2 were studied. Changes in intracellular Ca2+ concentration levels ([Ca2+]i) of vascular smooth muscle (VSM) were measured by fura 2 fluorescence. Raloxifene or 17β-estradiol was equally effective in relaxing renal arteries from both sexes, with raloxifene being more potent than 17β-estradiol. Endothelial denudation did not affect raloxifene- or 17β-estradiol-induced relaxation. NG-nitro-l-arginine methyl ester, charybdotoxin plus apamin, indomethacin, or ICI-182, 780 did not modify the effect of raloxifene. Raloxifene caused similar relaxations in rings contracted by U-46619 and high K+. Nifedipine attenuated the potency of raloxifene. Raloxifene reduced CaCl2-induced contractions. K+ (80 mM) stimulated an increase in VSM [Ca2+]i, and raloxifene attenuated this effect. Raloxifene-induced reduction of contraction and increase in VSM [Ca2+]i were insensitive to ICI-182, 780. In summary, raloxifene causes relaxation in rat renal arteries; this effect is independent of a functional endothelium and is not mediated by ICI 182, 780-sensitive estrogen receptors. Raloxifene inhibited both contractions and VSM [Ca2+]i in response to CaCl2, indicating that raloxifene relaxes rat renal arteries primarily through inhibiting Ca2+ influx via Ca2+ channels. There is little sex difference in raloxifene-induced relaxation.
Collapse
MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Animals
- Calcium/antagonists & inhibitors
- Calcium/metabolism
- Calcium/pharmacology
- Calcium Channel Blockers/pharmacology
- Dose-Response Relationship, Drug
- Estradiol/pharmacology
- Female
- In Vitro Techniques
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Nifedipine/pharmacology
- Raloxifene Hydrochloride/pharmacology
- Rats
- Rats, Sprague-Dawley
- Renal Artery/drug effects
- Renal Artery/metabolism
- Renal Artery/physiology
- Selective Estrogen Receptor Modulators/pharmacology
- Vasoconstrictor Agents/pharmacology
- Vasodilation/drug effects
Collapse
|
15
|
Abstract
Estrogen receptors (ERs) are localized to many sites within the cell, potentially contributing to overall estrogen action. In the nucleus, estrogen mainly modulates gene transcription, and the resulting protein products determine the cell biological actions of the sex steroid. In addition, a small pool of ERs localize to the plasma membrane and signal mainly though coupling, directly or indirectly, to G proteins. In response to steroid, signal transduction modulates both nontranscriptional and transcriptional events and impacts both the rapid and more prolonged actions of estrogen. Cross-talk from membrane-localized ERs to nuclear ERs can be mediated through growth factor receptor tyrosine kinases, such as epidermal growth factor receptor and IGF-I receptor. Growth factor receptors enact signal transduction to kinases such as ERK and phosphatidylinositol 3-kinase that phosphorylate and activate nuclear ERs, and this can also occur in the absence of sex steroid. A complex relationship between the membrane and nuclear effects of estrogen also involves membrane-initiated phosphorylation of coactivators, recruiting these proteins to the nuclear transcriptosome. Finally, large pools of cytoplasmic ERs exist, and some are localized to mitochondria. The integration of sex steroid effects at distinct cellular locations of its receptor leads to important cellular physiological outcomes and are manifest in both reproductive and nonreproductive organs.
Collapse
Affiliation(s)
- Ellis R Levin
- Division of Endocrinology, Veterans Affairs Medical Center, Long Beach, California 90822, USA.
| |
Collapse
|
16
|
Hirata A, Minamino T, Asanuma H, Sanada S, Fujita M, Tsukamoto O, Wakeno M, Myoishi M, Okada KI, Koyama H, Komamura K, Takashima S, Shinozaki Y, Mori H, Tomoike H, Hori M, Kitakaze M. Erythropoietin Just Before Reperfusion Reduces Both Lethal Arrhythmias and Infarct Size via the Phosphatidylinositol-3 Kinase-Dependent Pathway in Canine Hearts. Cardiovasc Drugs Ther 2005; 19:33-40. [PMID: 15883754 DOI: 10.1007/s10557-005-6895-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although recent studies suggest that erythropoietin (EPO) may reduce multiple features of the myocardial ischemia/reperfusion injury, the cellular mechanisms and the clinical implications of EPO-induced cardioprotection are still unclear. Thus, in this study, we clarified dose-dependent effects of EPO administered just before reperfusion on infarct size and the incidence of ventricular fibrillation and evaluated the involvement of the phosphatidylinositol-3 (PI3) kinase in the in vivo canine model. The canine left anterior descending coronary artery was occluded for 90 min followed by 6 h of reperfusion. A single intravenous administration of EPO just before reperfusion significantly reduced infarct size (high dose (1,000 IU/kg): 7.7 +/- 1.6%, low dose (100 IU/kg): 22.1 +/- 2.4%, control: 40.0 +/- 3.6%) in a dose-dependent manner. Furthermore, the high, but not low, dose of EPO administered as a single injection significantly reduced the incidence of ventricular fibrillation during reperfusion (high dose: 0%, low dose: 40.0%, control: 50.0%). An intracoronary administration of a PI3 kinase inhibitor, wortmannin, blunted the infarct size-limiting and anti-arrhythmic effects of EPO. Low and high doses of EPO equally induced Akt phosphorylation and decreased the equivalent number of TUNEL-positive cells in the ischemic myocardium of dogs. These effects of EPO were abolished by the treatment with wortmannin. In conclusion, EPO administered just before reperfusion reduced infarct size and the incidence of ventricular fibrillation via the PI3 kinase-dependent pathway in canine hearts. EPO administration can be a realistic strategy for the treatment of acute myocardial infarction.
Collapse
Affiliation(s)
- Akio Hirata
- Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Sanada S, Asanuma H, Minamino T, Node K, Takashima S, Okuda H, Shinozaki Y, Ogai A, Fujita M, Hirata A, Kim J, Asano Y, Mori H, Tomoike H, Kitamura S, Hori M, Kitakaze M. Optimal windows of statin use for immediate infarct limitation: 5'-nucleotidase as another downstream molecule of phosphatidylinositol 3-kinase. Circulation 2004; 110:2143-9. [PMID: 15451788 DOI: 10.1161/01.cir.0000143830.59419.73] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Although statins are reported to have a cardioprotective effect, their immediate direct influence on ischemia-reperfusion injury and the underlying mechanisms remain obscure. We investigated these issues an in vivo canine model. METHODS AND RESULTS Dogs were subjected to coronary occlusion (90 minutes) and reperfusion (6 hours) immediately after injection of pravastatin (0.2, 2, or 10 mg/kg), pitavastatin (0.01, 0.1, or 0.5 mg/kg), or cerivastatin (0.5, 5, or 50 microg/kg). Then myocardial phosphatidylinositol 3-kinase (PI3-K) and 5'-nucleotidase activities were measured, as well as infarct size. After 15 minutes of reperfusion, pravastatin caused dose-dependent activation of Akt and ecto-5'-nucleotidase in the ischemic zone, and the effect was significant at higher doses. Pitavastatin also significantly increased these activities, and its optimal dose was within the clinical range, whereas cerivastatin caused activation at the lowest dose tested. In all cases, both Akt and ecto-5'-nucleotidase showed activation in parallel, and this activation was completely abolished by wortmannin, a PI3-K inhibitor. The magnitude of the infarct-limiting effect paralleled the increase in Akt and ecto-5'-nucleotidase activity and was blunted by administration of wortmannin, alpha,beta-methyleneadenosine-5'-diphosphate, or 8-sulfophenyltheophylline during reperfusion. Both collateral flow and the area at risk were comparable for all groups. CONCLUSIONS Activation of ecto-5'-nucleotidase after ischemia by PI3-K activation may be crucial for immediate infarct-size limitation by statins. There seems to be an optimal dose for each statin that is independent of its clinical cholesterol-lowering effect.
Collapse
Affiliation(s)
- Shoji Sanada
- Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, Suita, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|