Featured Research

from universities, journals, and other organizations

Surgical menopause may prime brain for stroke, Alzheimer's

Date:
March 28, 2013
Source:
Medical College of Georgia at Georgia Regents University
Summary:
Removing the ovaries before menopause, appears to leave more of the brain vulnerable to stroke and increase the risk of Alzheimer's disease, researchers report.

This is Dr. Brann and Dr. Zhang.
Credit: GRU Photographer

Women who abruptly and prematurely lose estrogen from surgical menopause have a two-fold increase in cognitive decline and dementia.

Related Articles


"This is what the clinical studies indicate and our animal studies looking at the underlying mechanisms back this up," said Brann, corresponding author of the study in the journal Brain. "We wanted to find out why that is occurring. We suspect it's due to the premature loss of estrogen."

In an effort to mimic what occurs in women, Brann and his colleagues looked at rats 10 weeks after removal of their estrogen-producing ovaries that were either immediately started on low-dose estrogen therapy, started therapy 10 weeks later or never given estrogen.

When the researchers caused a stroke-like event in the brain's hippocampus, a center of learning and memory, they found the rodents treated late or not at all experienced more brain damage, specifically to a region of the hippocampus called CA3 that is normally stroke-resistant.

To make matters worse, untreated or late-treated rats also began an abnormal, robust production of Alzheimer's disease-related proteins in the CA3 region, even becoming hypersensitive to one of the most toxic of the beta amyloid proteins that are a hallmark of Alzheimer's.

Both problems appear associated with the increased production of free radicals in the brain. In fact, when the researchers blocked the excessive production, heightened stroke sensitivity and brain cell death in the CA3 region were reduced.

Interestingly the brain's increased sensitivity to stressors such as inadequate oxygen was gender specific, Brann said. Removing testes in male rats, didn't affect stroke size or damage.

Although exactly how it works is unknown, estrogen appears to help protect younger females from problems such as stroke and heart attack. Their risks of the maladies increase after menopause to about the same as males. Follow up studies are needed to see if estrogen therapy also reduces sensitivity to the beta amyloid protein in the CA3 region, as they expect, Brann noted.

Brann earlier showed that prolonged estrogen deprivation in aging rats dramatically reduces the number of brain receptors for the hormone as well as its ability to prevent strokes. Damage was forestalled if estrogen replacement was started shortly after hormone levels drop, according to the 2011 study in the journal Proceedings of the National Academy of Sciences.

The surprising results of the much-publicized Women's Health Initiative -- a 12-year study of 161,808 women ages 50-79 -- found hormone therapy generally increased rather than decreased stroke risk as well as other health problems. Critics said one problem with the study was that many of the women, like Brann's aged rats, had gone years without hormone replacement, bolstering the case that timing is everything.

The research was supported by the National Institute of Neurological Disorders and Stroke, an American Heart Association Scientist Development grant and a National Natural Science Foundation grant.


Story Source:

The above story is based on materials provided by Medical College of Georgia at Georgia Regents University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Q.-g. Zhang, R.-m. Wang, E. Scott, D. Han, Y. Dong, J.-y. Tu, F. Yang, G. Reddy Sareddy, R. K. Vadlamudi, D. W. Brann. Hypersensitivity of the hippocampal CA3 region to stress-induced neurodegeneration and amyloidogenesis in a rat model of surgical menopause. Brain, 2013; DOI: 10.1093/brain/awt046

Cite This Page:

Medical College of Georgia at Georgia Regents University. "Surgical menopause may prime brain for stroke, Alzheimer's." ScienceDaily. ScienceDaily, 28 March 2013. <www.sciencedaily.com/releases/2013/03/130328125323.htm>.
Medical College of Georgia at Georgia Regents University. (2013, March 28). Surgical menopause may prime brain for stroke, Alzheimer's. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/03/130328125323.htm
Medical College of Georgia at Georgia Regents University. "Surgical menopause may prime brain for stroke, Alzheimer's." ScienceDaily. www.sciencedaily.com/releases/2013/03/130328125323.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
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.

Save/Print:
Share:  

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



Save/Print:
Share:  

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