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Effects of Estetrol on Thrombotic and Growth Parameters Associated With Vascular Remodeling

RK Dubey, M Rosselli, B Imthurn, M Szutkowska, GS Merki

Clinic for Reproductive Endocrinology, University Hospital Zurich, Switzerland

Speakers Disclosures

No Financial Interest

No Conflict of Interest

Nothing to Disclose

15a - Hydroxylase 16a - Hydroxylase

Estetrol - Endogenous Biosynthesis

Expressed byFetal Liver

During Pregnancy

End Product –No Reverse Metabolism

ERα/ERβ

SteroidLigands

Ki ERα (nM) Ki ERβ (nM) Preference(%)

EE 0.23 0.025 11

E2 0.21 0.015 7

E4 4.9 19 400

Estetrol has no Binding Affinity for Sex Hormone Binding Globulin (SHBG)Elimination Half Life in Humans = 28 hrsEstetrol Levels Peak at Term Pregnancy = 1.2 ng/ml

(They are 12 Times Higher in Fetal than Maternal Plasma)

Estetrol Pharmacology

Estetrol

ContraceptiveActions

NeuroprotectiveAntiestrogenicin ER positiveBreast Cancer

Anticarcinogenic(prostate)Positive Actions

Lipids/Lipoproteins

Bone

eNOS/Nitric Oxide

Hot Flush LiverMetabolism

Vascular Complications in Women

Use of Contraceptives are associated with Cardiovascular

Complications both arterial & Venous, (Myocardial & Cerebral

Infarction; Venous Thromboembolism / deep vain thrombosis,

pulmonary embolism and cerebrovascular accidents.

Use of combined oral contraceptives (CC) increases the risk to

develop VTE.

Coronary Artery Disease is the Leading Cause of Mortality in Women.

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Coronary ArteryDisease

Coronary Artery Disease

P. Libby Nature 2002;420:868-874

Estradiol Inhibits Injury-Induced Vascular Occlusion :Potential Role of ERs

Oparil and Colleagues,Circulation 1997;Dubey et al., Arterioscler Thromb Vasc Biol 2000

-Est

radi

ol+

Estra

diol

ER-a

ER-b

ER-a

ER-b

Estetrol

What are it‘s Effects on Mechanisms Which

Contribute to Vascular Remodeling Leading to

Vasoocclusive Disorders ?

Could It Interfere with Vasoprotective / Anti-

Vasoocclusive Actions of Estradiol

Cellular Processes Associated with Vascular Remodeling & Vasoocclusive Disorders

Faxon et al. Circulation 2004; 109:2617-2625

Experimental Approach

Growth Effects of Estetrol Assessed in Vitro Using Cultured Human Arterial Smooth Muscle Cells

Cell Proliferation Assessed by Counting Cell Number

Cell Migration by Assessing Wound Closure in a Scratch Assay

Molecular Indicators Assayed Using Western Blotting Cel

l Num

ber (

SMC

s x

103 )

Estetrol (nMol/L)

Effects of Estetrol on Human Arterial SMC Growth

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Estetrol Decreases the Antimitogenic Actions of Estradiol in Human Arterial SMCs

Effects of Estradiol in SMCs : Mechanism(s) of Action

E E

ERE

ER-a

mRNA

E

ER-b

E

ER-a

Estradiol

EffectorMolecules

Anti-Proliferative Actions

nucleus

SMCs

GPER

Vascular Protection

Role of Estrogen Receptors in Mediating Growth Effects of Estradiol and Estetrol in SMCs

*§

*

Scratch Assay

Time

GapArea

Increase

Cell Migration Analysis

**

** *

* * *

* P<0.05 vs FCS alone

§ §

Effects of Estetrol and Estradiol on Human Arterial SMC Migration

FCS (2.5%) + Treatment (nM)

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Role of Estrogen Receptors in Mediating Inhibitory Effects of Estradiol on SMC Migration

*

§§

§

§

§ P<0.05 vs E2

Role of Estrogen Receptors in Mediating Inhibitory Effects of Estetrol on SMC Migration

*

§ §

§ P<0.05 vs E4

Conclusion I

Estradiol Inhibits SMC Proliferation whereasEstetrol is a weak Inducer of SMC Proliferation.

Estetrol Attenuates the Growth Inhibitory Actions ofEstradiol on SMCs.

Whether Abrogatory Actions of Estetrol on EstradiolMediated Anti-Proliferative and Anti-MigratoryActions in SMCs would Result in Deleterious Effectson the Vasulature Remains Unknown and Needs tobe Further Investigated.

Estetrol and Vascular ActionsTissue Factor-Thrombosis

Mackman N Arterioscler Thromb Vasc Biol 2004; 24: 1015-1022

020406080

100120140160180200

ctrl 100 nM E4 1uM E4 100 nM E2

* *

OD

% o

f Con

trol

Treatment

TF

Control 100 nM 1 µM100 nM

E2

E4

β-actin

Estetrol Induces Tissue Factor Expression in Human Arterial Smooth Muscle Cells

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0

50

100

150

200

250

ctrl 100 nME4

1uM E4 100 nME2

** *

OD

% o

f Con

trol

Treatment

PAI-1

control 100 nM 1 µM100 nM

E2

E4

β-actin

Estetrol Induces PAI-1 Expression in Human Arterial Smooth Muscle Cells

Conclusion II

Estradiol and Estetrol Upregulate the Expression of KeyProteins Associated with Thrombosis in Human ArterialSMCs.

Compared to Estradiol, Estetrol is less Potent in InducingTF-1 and PAI-1.

Estetrol may be safer than Estradiol on Thrombotic &Coagulatory Actions.

More in-depth Studies are Required to InvestigateWhether Estetrol can Attenuate the Deleterious Effects ofEstrogenic Contraceptives and Estradiol on Thrombosis.

Good Actions

Deleterious Actions

Estetrol