Raloxifene and endothelial function in healthy postmenopausal women

doi:10.1067/mob.2003.28

American Journal of Obstetrics and Gynecology

Volume 188, Issue 2, February 2003, Pages 304-309

https://doi.org/10.1067/mob.2003.28 Get rights and content

Abstract

Objective: The purpose of this study was to determine the effects of raloxifene on endothelial function in healthy, postmenopausal women. Study design: This was a randomized, double-blind, placebo-controlled crossover trial. Subjects (n = 19; mean age, 61 years) underwent endothelial function testing at baseline and after treatment with placebo or raloxifene (60 mg per day for 6 weeks). Results: Brachial artery diameter change (flow-mediated dilation) increased 5.0% with placebo and 8.56% with raloxifene (SE = 1.83, P = .03) in response to a hyperemic stimulus; an adjustment of this response for a variation in stimulus intensity resulted in greater discrimination (P = .009). The ratio of area under the curve response to area under the curve reference with the use of laser Doppler measures was 1.18 for placebo and 1.28 for raloxifene (P = .05). Flow-mediated dilation and area under the curve ratio correlated significantly (r = 0.33, P = .04). Conclusion: Treatment with raloxifene enhanced endothelial-mediated dilation in brachial arteries and digital vessels in healthy, postmenopausal women. A potential mechanism for a cardioprotective effect of raloxifene is suggested and warrants further study. (Am J Obstet Gynecol 2003;188:304-9.)

Section snippets

Subjects

Twenty healthy postmenopausal women were enrolled, of whom 1 was subsequently deemed ineligible because of undisclosed Raynaud's phenomenon; the remaining cohort of 19 women was studied. Postmenopausal was defined as the absence of menses for at least 1 year. Inclusion criteria were defined as no known cardiovascular or other chronic debilitating disease, no vasoactive medication use including vitamin E, and no use of any postmenopausal hormone replacement therapy. All subjects were under the

Subjects

Demographic data for the 19 subjects were provided in Table I.

. Baseline subject demographic characteristics (n = 19)

Variable	Mean	SE
Age (y)	61	1.7
Weight (kg)	72.2	2.4
Body mass index (kg/m²)	28.3	1.2
SBP	130.7	4.0
DBP	80.4	7.0
Reference skin temperature (°C)	31.5	0.56
Time from menopause (mo)	171	26.5

The mean age of study participants was 61 years, and the mean time from menopause was 171 months. Estradiol and follicle-stimulating hormone levels were not measured, because only 4 women were under the age of 57 years;

Comment

The administration of raloxifene (60 mg/d) compared with placebo, significantly improved endothelial-mediated dilation in brachial arteries and digital vessels in a small group of healthy postmenopausal women. High-resolution ultrasound brachial artery measures and LDV parameters correlated significantly. With the use of a novel stimulus-adjusted response measure, the difference between raloxifene and placebo was even greater.

A variety of estrogens has been shown to improve endothelium-mediated

Acknowledgements

We thank Mrs Michelle LaRovera and Mrs Jennifer Ballard for technical assistance.

References (25)

R. Vogel
Coronary risk factor, endothelial function, and atherosclerosis: A review
Clin Cardiol
(1997)
D Herrington et al.
Estrogen modulates coronary vasomotor responses in postmenopausal women with early atherosclerosis
Am J Cardiol
(1994)
P Collins et al.
17 beta-Estradiol attenuates acetylcholine-induced coronary arterial constriction in women but not men with coronary heart disease
Circulation
(1995)
D Gilligan et al.
Acute vascular effects of estrogen in postmenopausal women
Circulation
(1994)
T Caulin-Glaser et al.
Estradiol regulation of human endothelial cell basal nitric oxide release, independent of cytosolic Ca⁺⁺ mobilization
Circ Res
(1997)
T Simoncini et al.
Raloxifene acutely stimulates nitric oxide release from human endothelial cells via an activation of endothelial nitric oxide synthase
J Clin Endocrinol Metab
(2000)
G Figtree et al.
Raloxifene acutely relaxes rabbit coronary arteries in vitro by an estrogen receptor-dependent and nitric oxide-dependent mechanism
Circulation
(1999)
W Zoma et al.
Coronary and uterine vascular resonses to raloxifene in the sheep
Am J Obstet Gynecol
(2000)
DM Herrington et al.
Cardiovascular effects of droloxifene, a new selective estrogen receptor modulator, in healthy postmenopausal women
Arterioscler Thromb Vasc Biol
(2000)
A Saitta et al.
Randomized, double-blind, placebo-controlled study on effects of raloxifene and hormone replacement therapy on plasma no concentrations, endothelin-1 levels, and endothelium-dependent vasodilation in postmenopausal women
Arterioscler Thromb Vasc Biol
(2001)

E Cerquetani et al.

Hormone replacement therapy but not raloxifene improves endothelial function in postmenopausal women with increased cardiovascular risk

K Sorenson et al.

Non-invasive measurement of human endothelium-dependent arterial responses: Accuracy and reproducibility

Br Heart J

(1995)

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2016, Steroids
Citation Excerpt :
Moreover, recent clinical studies have found an association between Gper gene function and arterial blood pressure [108]. In addition to numerous preclinical investigations [109–115], clinical studies have shown that SERMs or SERDs improve vasodilation [116–118] and arterial stiffness [119], lower blood pressure [120,121], improve the lipid and glucose profile [122–126], reduce circulating fibrinogen levels [127], and reduce cardiovascular events in postmenopausal women [128,129] – all effects that are compatible with GPER activation while blocking ERα and/or ERβ would be expected to yield the opposite effects [9]. Finally, a common side effect in breast cancer patients receiving the SERD fulvestrant frequently experience hypotension as an unwanted side effect [121], which so far could not been explained mechanistically.
It has been 20 years that the G protein-coupled estrogen receptor (GPER) was cloned as the orphan receptor GPR30 from multiple cellular sources, including vascular endothelial cells. Here, I will provide an overview of estrogen biology and the historical background leading to the discovery of rapid vascular estrogen signaling. I will also review the recent advances in the understanding of the mechanisms underlying GPER function, its role in physiology and disease, some of the currently available GPER-targeting drugs approved for clinical use such as SERMs (selective estrogen receptor modulators) and SERDs (selective estrogen receptor downregulators). Many of currently used drugs such as tamoxifen, raloxifene, or faslodex™/fulvestrant were discovered targeting GPER many years after they had been introduced to the clinics for entirely different purposes. This has important implications for the clinical use of these drugs and their modes of action, which I have termed ‘reverse translational medicine’. In addition, environmental pollutants known as ‘endocrine disruptors’ have been found to bind to GPER. This article also discusses recent evidence in these areas as well as opportunities in translational clinical medicine and GPER research, including medical genetics, personalized medicine, prevention, and its theranostic use.
XbaI polymorphism of the estrogen receptor alpha gene influences the effect of raloxifene on the endothelial function
2010, Maturitas
Cardiovascular disease is the leading cause of death in postmenopausal women and estrogen deficiency may be an important factor in its development. The selective estrogen receptor modulator, raloxifene, exerts a part of its actions through the estrogen receptor alpha (ESR1) activation. We explored if polymorphisms of the ESR1 modify the effects of 6 months raloxifene treatment on endothelial function.
A total of 53 postmenopausal women, mean age 59.7 ± 6.2, finished the prospective clinical trial. The PvuII, XbaI, and P325P polymorphisms of the ESR1 gene were analyzed. In all subjects endothelium-dependent flow mediated dilatation (FMD) and cell adhesion molecules (CAM) ICAM-1, VCAM-1 and E-selectin were measured before and after 6 months of raloxifene treatment.
There was no difference in FMD between the ESR1 genotypes, at baseline. After raloxifene treatment, the FMD was significantly greater in subjects with XX genotype of XbaI polymorphism compared to xx (p = 0.03) and borderline greater when compared to Xx genotype (p = 0.053). The FMD increased significantly with raloxifene treatment in women with Xx genotype of XbaI and Pp genotype of PvuII polymorphisms (p = 0.027 and p = 0.034, respectively). The P325P polymorphism did not influence the FMD after raloxifene. None of the ESR1 gene polymorphisms had any impact on the levels of CAM before or after the treatment. When analysing the whole group, a significant decrease in E-selectin (p < 0.001) and a small increase in ICAM-1 levels (p = 0.029) was observed with raloxifene treatment, but no influence on VCAM-1 levels or FMD overall was seen.
Our data suggest that XbaI and possibly PvuII polymorphisms of the ESR1 gene influence the impact of raloxifene treatment on endothelial function. This effect could be of pharmacogenomic and clinical importance.
Signaling, physiological functions and clinical relevance of the G protein-coupled estrogen receptor GPER
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GPR30, now named GPER1 (G protein-coupled estrogen receptor1) or GPER here, was first identified as an orphan 7-transmembrane G protein-coupled receptor by multiple laboratories using either homology cloning or differential expression and subsequently shown to be required for estrogen-mediated signaling in certain cancer cells. The actions of estrogen are extensive in the body and are thought to be mediated predominantly by classical nuclear estrogen receptors that act as transcription factors/regulators. Nevertheless, certain aspects of estrogen function remain incompatible with the generally accepted mechanisms of classical estrogen receptor action. Many recent studies have revealed that GPER contributes to some of the actions of estrogen, including rapid signaling events and rapid transcriptional activation. With the introduction of GPER-selective ligands and GPER knockout mice, the functions of GPER are becoming more clearly defined. In many cases, there appears to be a complex interplay between the two receptor systems, suggesting that estrogen-mediated physiological responses may be mediated by either receptor or a combination of both receptor types, with important medical implications.
Characterisation of the relaxant response to raloxifene in porcine coronary arteries
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Citation Excerpt :
Raloxifene, a second generation SERM, has been approved for use in the prevention and treatment of osteoporosis in postmenopausal women (Vogelvang et al., 2006). In addition, it has been shown that treatment with raloxifene enhances flow-mediated vasodilatation, increases plasma nitric oxide (NO) concentrations, and decreases plasma endothelin-1 levels in healthy postmenopausal women (Saitta et al., 2001; Sarrel et al., 2003). However, in postmenopausal women whose arteries were affected by advanced atherosclerosis, raloxifene failed to improve vascular functions (Griffiths et al., 2003).
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_2α (PGF_2α; 3 μM) were concentration-dependently relaxed by raloxifene (0.1–10 μM). Relaxation was not inhibited by the estrogen receptor antagonist 7α-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]-estra-1,3,5(10)-triene-3,17β-diol (ICI 182,780; 1 μM). Preincubation with raloxifene (1–3 μM) caused an inhibition of the KCl or PGF_2α-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 Ca²⁺ 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 μM). Calcium-induced contractions in Ca²⁺-free high K⁺ (60 mM) depolarising medium were concentration-dependently inhibited by raloxifene (0.3–3 μM). If arterial rings were incubated with the L-type Ca²⁺ 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 μM), cumulative concentration–response curves to Ca²⁺ were shifted to the left. Raloxifene (0.3–3 μM) 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 μM), 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 Ca²⁺ 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.
Effect of raloxifene on aortic elasticity in healthy postmenopausal women
2005, American Heart Journal
Citation Excerpt :
Although the effect of raloxifene on cardiovascular morbidity and mortality in humans is unknown, current data suggest favorable effects on serum lipoproteins, coagulation markers, and endothelial function.7-9,11-13 In addition to exerting direct hepatic effects, raloxifene has direct actions on vascular endothelium and smooth muscle.8,9 Our study did not include investigation of any biochemical or hematologic parameters possibly associated with raloxifene administration, including serum lipid profiles, and therefore, we cannot provide any mechanistic explanations.
The effect of raloxifene on aortic elasticity in healthy postmenopausal women is unknown. The purpose of the present study was to examine the effect of raloxifene on aortic elasticity and cardiovascular structure and function in healthy postmenopausal women.
A randomized, crossover, double-blind, placebo-controlled clinical trial was performed. Fourteen healthy postmenopausal women received treatment with raloxifene 60 mg daily and matching placebo for 8 weeks with an 8-week washout period in between the 2 treatment periods. Cardiovascular magnetic resonance imaging was used to assess ascending thoracic and abdominal aortic elasticity and cardiovascular structure and function (left ventricular volumes, ejection fraction, and mass and mitral annular displacement) before and at the end of each treatment period.
Administration of raloxifene had no significant effect on either heart rate or systemic blood pressure. Raloxifene treatment was associated with a small decrease of the ascending aorta wall thickness (pretreatment 2.4 ± 0.3 vs posttreatment 2.2 ± 0.2 mm, P = .01). Consequently, there was an increase in the Young's elastic modulus after raloxifene treatment at the ascending thoracic aorta but not the abdominal aorta. There were no significant differences in aortic compliance or any cardiac indexes after raloxifene treatment.
Raloxifene administration in healthy postmenopausal women over an 8-week period may decrease the aortic wall thickness but has no significant effects on aortic compliance or cardiac structure and function.
Raloxifene promotes prostacyclin release in human endothelial cells through a mechanism that involves cyclooxygenase-1 and -2
2005, Fertility and Sterility
To examine the effects of raloxifene on prostacyclin production by human umbilical vein endothelial cells (HUVEC) and to shed light on the molecular details of that action.
Cell culture for 4, 8, 16, 24, and 48 hours.
University research laboratory.
Source of HUVEC.
Measurement of prostacyclin production and of protein levels and mRNA expression of cyclooxygenase (COX)-1 and -2.
Prostacyclin production was measured by enzyme immunoassay, the mRNA expression of COX-1 was measured by quantitative real time-polymerase chain reaction, and the protein levels of COX-1 and -2 were measured by immunoblotting.
Raloxifene significantly increased prostacyclin release in a time- and dose-dependent manner, being higher than control after 24 hours. Raloxifene, at 0.1–10 nM, increased the mRNA expression of COX-1 and the protein content of both COX-1 as well as COX-2. All of these effects were independent of the classical pathway for estrogen receptor (ER) activation because the treatment of cells with the ER antagonist ICI 182780 did not eliminate any of the effects. Although treatment with either the selective COX-1 inhibitor SC-560 or the selective COX-2 inhibitor NS-398 significantly diminished prostacyclin release (20% ± 5% and 24% ± 7%, respectively), co-treatment with raloxifene and either SC-560 or NS-398 was followed by a smaller increase than that achieved by raloxifene alone. The nonselective COX inhibitor indomethacin, however, reduced prostacyclin production to 37% ± 11% of control values.
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^☆: Supported by Eli Lilly and Company, Indianapolis, Ind.

^☆☆: Reprint requests: Philip M. Sarrel, MD, Yale-Griffin Prevention Research Center, 130 Division St, Derby, CT 06418. E-mail: [email protected]

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Editor's ChoiceRaloxifene and endothelial function in healthy postmenopausal women☆,☆☆

Abstract

Section snippets

Subjects

Subjects

Comment

Acknowledgements

Coronary risk factor, endothelial function, and atherosclerosis: A review

Clin Cardiol

Estrogen modulates coronary vasomotor responses in postmenopausal women with early atherosclerosis

Am J Cardiol

17 beta-Estradiol attenuates acetylcholine-induced coronary arterial constriction in women but not men with coronary heart disease

Circulation

Acute vascular effects of estrogen in postmenopausal women

Circulation

Estradiol regulation of human endothelial cell basal nitric oxide release, independent of cytosolic Ca++ mobilization

Circ Res

Raloxifene acutely stimulates nitric oxide release from human endothelial cells via an activation of endothelial nitric oxide synthase

J Clin Endocrinol Metab

Raloxifene acutely relaxes rabbit coronary arteries in vitro by an estrogen receptor-dependent and nitric oxide-dependent mechanism

Circulation

Coronary and uterine vascular resonses to raloxifene in the sheep

Am J Obstet Gynecol

Cardiovascular effects of droloxifene, a new selective estrogen receptor modulator, in healthy postmenopausal women

Arterioscler Thromb Vasc Biol

Randomized, double-blind, placebo-controlled study on effects of raloxifene and hormone replacement therapy on plasma no concentrations, endothelin-1 levels, and endothelium-dependent vasodilation in postmenopausal women

Arterioscler Thromb Vasc Biol

Hormone replacement therapy but not raloxifene improves endothelial function in postmenopausal women with increased cardiovascular risk

Non-invasive measurement of human endothelium-dependent arterial responses: Accuracy and reproducibility

Br Heart J

Editor's Choice
Raloxifene and endothelial function in healthy postmenopausal women☆,☆☆

Estradiol regulation of human endothelial cell basal nitric oxide release, independent of cytosolic Ca⁺⁺ mobilization