Natural Estrogen Reduces Stroke Damage In Female Animals

November 22, 1996

Johns Hopkins scientists have shown that natural levels of estrogen offer females three times more protection against brain damage from strokes than their estrogen-lacking male counterparts.

The study in rats, funded by the National Institutes of Health, concludes that the amount of brain that is "spared" once nourishing blood flow falls is related, in part, to circulating estrogen level.

"From our data, it seems likely that residual blood flow to the brain during stroke is conserved when estrogen is present in adequate amounts," says Patricia Hurn, Ph.D., an assistant professor of research anesthesiology and critical care medicine. "We are now in the process of determining how much estrogen is required for neuroprotection and the biological and cellular mechanisms involved."

Hurn and her team created strokes in anesthetized male and female rats by blocking blood flow for two hours through the middle cerebral artery, a brain blood vessel commonly linked to cerebrovascular disease and stroke in humans.

"When we measured blood flow levels, we found female rats were somehow able to get more blood around the blockage of the artery," she says. She will present her results November 21 at the annual meeting of the Society for Neuroscience in Washington, D.C.

When they created strokes in female rats whose ovaries had been surgically removed, cutting estrogen levels by almost half, stroke damage was essentially the same as in the males.

She and her colleagues are now treating both male and female animals with varying amounts of estrogen and creating strokes to determine the links between estrogen dose and brain protection.

"This will be an important step toward determining whether we can use estrogen as a brain-protective therapy," says Hurn. They also will look at the role of nitric oxide and enzymes that help dilate blood vessels.

Women are generally at lower risk than men for cardiovascular disease, including "brain attack" or stroke.

"Many studies in humans and animals showed that estrogen is protective in heart disease, but our understanding of estrogen's effects in the brain as a neuroprotective agent is very limited," says Hurn. "Hormone replacement therapies are commonly prescribed for women who are undergoing natural or surgical menopause, and this could pose a potential risk or benefit for a woman when a stroke occurs.

"We need more information both for these women and for those with cerebrovascular disease who might benefit from hormone therapies," she concludes.


Johns Hopkins Medical Institutions' news releases can be accessed on-line through the following services:

-- World Wide Web at
-- CompuServe in the SciNews-MedNews library of the Journalism Forum under file extension ".JHM"; also in NASW Online in same forum.
-- JHMI toll-free Health NewsFeed BBS at 1-800-JHH-0046.
-- Quadnet: send email to: In the body of the message type "info Quadnet."
-- To enroll in our direct e-mail news release service, call 410-955-4288.

Johns Hopkins Medicine

Related Heart Disease Articles from Brightsurf:

Cellular pathway of genetic heart disease similar to neurodegenerative disease
Research on a genetic heart disease has uncovered a new and unexpected mechanism for heart failure.

Mechanism linking gum disease to heart disease, other inflammatory conditions discovered
The link between periodontal (gum) disease and other inflammatory conditions such as heart disease and diabetes has long been established, but the mechanism behind that association has, until now, remained a mystery.

New 'atlas' of human heart cells first step toward precision treatments for heart disease
Scientists have for the first time documented all of the different cell types and genes expressed in the healthy human heart, in research published in the journal Nature.

With a heavy heart: How men and women develop heart disease differently
A new study by researchers from McGill University has uncovered that minerals causing aortic heart valve blockage in men and women are different, a discovery that could change how heart disease is diagnosed and treated.

Heart-healthy diets are naturally low in dietary cholesterol and can help to reduce the risk of heart disease and stroke
Eating a heart-healthy dietary pattern rich in vegetables, fruits, whole grains, low-fat dairy products, poultry, fish, legumes, vegetable oils and nuts, which is also limits salt, red and processed meats, refined-carbohydrates and added sugars, is relatively low in dietary cholesterol and supports healthy levels of artery-clogging LDL cholesterol.

Pacemakers can improve heart function in patients with chemotherapy-induced heart disease
Research has shown that treating chemotherapy-induced cardiomyopathy with commercially available cardiac resynchronization therapy (CRT) delivered through a surgically implanted defibrillator or pacemaker can significantly improve patient outcomes.

Arsenic in drinking water may change heart structure raising risk of heart disease
Drinking water that is contaminated with arsenic may lead to thickening of the heart's main pumping chamber in young adults, according to a new study by researchers at Columbia University Mailman School of Public Health.

New health calculator can help predict heart disease risk, estimate heart age
A new online health calculator can help people determine their risk of heart disease, as well as their heart age, accounting for sociodemographic factors such as ethnicity, sense of belonging and education, as well as health status and lifestyle behaviors.

Wide variation in rate of death between VA hospitals for patients with heart disease, heart failure
Death rates for veterans with ischemic heart disease and chronic heart failure varied widely across the Veterans Affairs (VA) health care system from 2010 to 2014, which could suggest differences in the quality of cardiovascular health care provided by VA medical centers.

Heart failure: The Alzheimer's disease of the heart?
Similar to how protein clumps build up in the brain in people with some neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, protein clumps appear to accumulate in the diseased hearts of mice and people with heart failure, according to a team led by Johns Hopkins University researchers.

Read More: Heart Disease News and Heart Disease Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to