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Updated: Sep 1, 2026
Imaging of Estrogen Receptor-α in Rat Pial Arterioles using a Digital Immunofluorescent Microscope
Published on: November 29, 2011
Estrogen inhibits the vascular injury response in estrogen receptor alpha-deficient mice
M D Iafrati1, R H Karas, M Aronovitz
1Molecular Cardiology Research Center, New England Medical Center, Tupper Research Institute, Boston, Massachusetts 02111, USA.
Abstract:
The atheroprotective effects of estrogen in women are well recognized, but the underlying mechanisms responsible are not well understood. Blood vessel cells express the classic estrogen receptor, ER alpha (ref. 2-6), and are directly affected by estrogen, which inhibits the development of atherosclerotic and injury-induced vascular lesions. We have generated mice in which the ER alpha gene is disrupted and have used a mouse model of carotid arterial injury to compare the effects of estrogen on wild-type and estrogen receptor-deficient mice. Increases in vascular medial area and smooth muscle cell proliferation were quantified following vascular injury in ovariectomized mice treated with vehicle or with physiologic levels of 17 beta-estradiol. Surprisingly, in both wild-type and estrogen receptor-deficient mice, 17 beta-estradiol markedly inhibited to the same degree all measures of vascular injury. These data demonstrate that estrogen inhibits vascular by a novel mechanism that is independent of the classic estrogen receptor, ER alpha.
Insights
Estrogen protects against vascular injury, but not through the known estrogen receptor alpha. This study reveals a novel, estrogen receptor-independent pathway for estrogen
Area of Science:
- Cardiovascular Biology
- Endocrinology
- Vascular Medicine
Background:
- Estrogen is known to have atheroprotective effects in women.
- The mechanisms behind estrogen's vascular protection are not fully understood.
- Blood vessel cells express estrogen receptor alpha (ERα), which is directly affected by estrogen.
Purpose of the Study:
- To investigate the role of estrogen receptor alpha (ERα) in mediating estrogen's protective effects on vascular injury.
- To determine if estrogen inhibits vascular injury through a mechanism independent of ERα.
Main Methods:
- Generated mice with a disrupted ERα gene.
- Utilized a mouse model of carotid arterial injury.
- Compared vascular injury responses in wild-type and ERα-deficient mice treated with 17β-estradiol.
Main Results:
- Estrogen (17β-estradiol) significantly inhibited vascular injury in both wild-type and ERα-deficient mice.
- The inhibitory effects of estrogen on vascular injury measures were similar in both genotypes.
- Vascular medial area and smooth muscle cell proliferation were quantified following injury.
Conclusions:
- Estrogen inhibits vascular injury through a novel mechanism.
- This mechanism is independent of the classic estrogen receptor, ERα.
- Estrogen receptor-independent pathways play a significant role in estrogen's vascular effects.
