Featured Research

from universities, journals, and other organizations

Estrogen's Role In Preventing Female Cardiac Disease

March 25, 2002
Cornell University
The role of the hormone estrogen in protecting the female heart from enlargement and ultimate failure has been partly explained by studies with genetically engineered mice, according to researchers at Cornell and Vanderbilt universities.

ITHACA, N.Y. -- The role of the hormone estrogen in protecting the female heart from enlargement and ultimate failure has been partly explained by studies with genetically engineered mice, according to researchers at Cornell and Vanderbilt universities.

Related Articles

Authors of the report in the latest issue of Nature ( March 21, 2002), "Oestrogen protects FKBP12.6 mice from cardiac hypertrophy," used the newly developed mouse "model" for an enlarged heart muscle to help explain estrogen's important role in preventing female cardiac hypertrophy -- extreme stress on the heart that is an early sign of congestive heart failure. However, the researchers say, much more research is needed into the complex causes of heart-muscle enlargement, a condition that leads to cardiac hypertrophy.

But results of the mouse studies, they say, are clear:

o Among mice genetically engineered for a predisposition to an enlarged heart muscle, male mice develop early signs of cardiac hypertrophy similar to the potentially fatal human condition, whereas similarly engineered female transgenic mice do not.

o Unless, that is, the female mice are treated with a drug to block natural estrogen production. By being unable to produce estrogen, the female mice had the same kind of cardiac hypertrophy as did the male mice -- indicating that estrogen production protects the females but not the males.

Referring to recent evaluations of estrogen replacement therapy for postmenopausal women, Michael Kotlikoff, professor and chair of clinical sciences at Cornell, says: "This finding correlates well with epidemiological data indicating an increase in the incidence of cardiomegaly (enlargement of the heart) in women after menopause. We are hopeful that these mice will provide insight to the processes leading to cardiac enlargement and the role that estrogen plays in ameliorating this process."

In addition to Kotlikoff, whose laboratory in the College of Veterinary Medicine at Cornell studies calcium channel signaling in muscle cells, authors of the Nature report include: Vanderbilt researchers Sidney Fleischer, Dong-Sheng Cheng, Julio A. Copello, Loice H. Jeyakumar, Tadashi Inagaml and Mark A. Magnuson; Mei Lin Collier of the University of Pennsylvania School of Veterinary Medicine; and Yong-Xiao Wang, Guang-Ju Ji, Ke-Yu Deng and Hong-Bo Xin of Cornell.

Now an assistant professor of biomedical sciences in Cornell's veterinary college, Xin was a postdoctoral researcher in Vanderbilt's Department of Biological Sciences when he developed the so-called knock-out mouse (or null mouse) that lacks the gene to produce the binding protein FKBP12.6. The protein is associated with receptors in heart muscle cells that signal for the contraction of muscle cells when calcium ions pass through channels, causing the heart to pump blood.

The Cornell-Vanderbilt mouse studies show for the first time how FKBP12.6 regulates the release of calcium in muscle-cell signaling, and also suggested that estrogen can protect mice -- and perhaps humans, too -- from the consequences of poorly regulated calcium release.

"When we examined calcium release in heart cells from knock-out mice, we found an abnormal calcium release process in both male and female mice," Kotlikoff says. "Calcium-release events were lengthened and increased in size in knock-out mice," he says, describing a kind of calcium overload to the signaling channels. "This is the first demonstration that FKBP12.6 participates in excitation/contraction coupling in the normal heart."

More surprising to the researchers, however, was the difference between male and female mice, both lacking the gene for FKBP12.6. Even though heart cells in female and male mice had the same genetic defect and the same degree of abnormal calcium release, females were somehow protected from developing cardiac enlargement in response to the defect.

"We wondered whether the factor protecting the female hearts was estrogen," Kotlikoff recalls. "And, indeed, when we blocked estrogen receptors in female knock-out mice [with the drug tamoxifen], they developed cardiac hypertrophy just like the males."

For years, estrogen replacement therapy has been prescribed to postmenopausal women for a variety of conditions, including stroke and heart disease, osteoporosis and hot flashes, although recent epidemiological studies have questioned the hormone's effectiveness in averting some problems, including stroke. Tamoxifen sometimes is prescribed to block estrogen production in women diagnosed with estrogen-related cancer, but that therapy also is somewhat controversial. Virtually all medical authorities agree that uncontrolled cardiac hypertrophy, without major intervention such as a transplant, results in death from heart failure.

Kotlikoff says that investigators need to learn how and why estrogen affects the abnormal growth of the heart muscle cells, called myocytes, as well as other kinds of body cells. He suggests that more detailed studies might find new evidence linking estrogen, blood pressure and hypertension. The body's system of cell-signaling triggers, receptors, channels, genes and regulatory mechanisms, he says, is "a very complex complex."Vanderbilt's Fleischer says: "With the knock-out mice, we have calcium signaling defined in a way that causes cardiac hypertrophy. We should be able to sort out the molecular signaling events that lead to this condition. It may also prove possible to slow down and even reverse the hypertrophy [in mice]. Chances are, it will be similar in humans."

The studies were supported by grants from the National Institutes of Health and by a Discovery Grant from Vanderbilt University.

Story Source:

The above story is based on materials provided by Cornell University. Note: Materials may be edited for content and length.

Cite This Page:

Cornell University. "Estrogen's Role In Preventing Female Cardiac Disease." ScienceDaily. ScienceDaily, 25 March 2002. <www.sciencedaily.com/releases/2002/03/020325080342.htm>.
Cornell University. (2002, March 25). Estrogen's Role In Preventing Female Cardiac Disease. ScienceDaily. Retrieved January 25, 2015 from www.sciencedaily.com/releases/2002/03/020325080342.htm
Cornell University. "Estrogen's Role In Preventing Female Cardiac Disease." ScienceDaily. www.sciencedaily.com/releases/2002/03/020325080342.htm (accessed January 25, 2015).

Share This

More From ScienceDaily

More Health & Medicine News

Sunday, January 25, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Disneyland Measles Outbreak Spreads To 5 States

Disneyland Measles Outbreak Spreads To 5 States

Newsy (Jan. 24, 2015) Much of the Disneyland measles outbreak is being blamed on the anti-vaccination movement. The CDC encourages just about everyone get immunized. Video provided by Newsy
Powered by NewsLook.com
Growing Measles Outbreak Worries Calif. Parents

Growing Measles Outbreak Worries Calif. Parents

AP (Jan. 23, 2015) Public health officials are rushing to contain a measles outbreak that has sickened 70 people across 6 states and Mexico. The AP&apos;s Raquel Maria Dillon has more. (Jan. 23) Video provided by AP
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
This Is What It's Like To Date A Med Student

This Is What It's Like To Date A Med Student

BuzzFeed (Jan. 23, 2015) Dating is now speed-dating... or studying. Video provided by BuzzFeed
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins