Featured Research

from universities, journals, and other organizations

Brain may use clot-busting drug naturally as protection against stroke

Date:
May 6, 2010
Source:
Emory University
Summary:
New research on the properties of the clot-busting stroke drug tPA (tissue-type plasminogen activator) suggests that tPA can act as a neuroprotectant and may form the keystone of an adaptive response to a reduction in blood flow. Scientists have shown that certain parts of the brains of mice lacking the gene for tPA are more vulnerable to stroke. In addition, tPA can protect neurons in the same part of the brain from the stress of hypoxia (low oxygen).

New research on the properties of the clot-busting stroke drug tPA (tissue-type plasminogen activator) suggests that tPA can act as a neuroprotectant and may form the keystone of an adaptive response to a reduction in blood flow.

Scientists from Emory University School of Medicine have shown that certain parts of the brains of mice lacking the gene for tPA are more vulnerable to stroke. In addition, tPA can protect neurons in the same part of the brain from the stress of hypoxia (low oxygen).

The results were recently published online in the Journal of Clinical Investigation.

tPA was introduced as a treatment for acute stroke in the 1990s. Physicians have debated its safety and effectiveness ever since then, because it can increase the likelihood of hemorrhage. Previous research has shown that in some situations, tPA can be seen as a neurotoxin. In addition to dissolving clots, tPA can increase the permeability of the blood-brain barrier, and it can cross from the blood vessels into the brain tissue, generating inflammation.

"tPA is not only a drug, it is a natural protein produced in response to hypoxia," says senior author Manuel Yepes, MD, associate professor of neurology at Emory University School of Medicine. "If you look at the parts of brain where the gene for tPA is turned on the most, one of these is the hippocampus. It is well known that the hippocampus is especially vulnerable to hypoxia compared with other regions of the brain. We believe there is a reason for this overlap."

The hippocampus is a structure in the middle of the brain thought to be responsible for memory formation. In mice lacking the gene for tPA, neurons in the hippocampus are more vulnerable to dying after a short simulated stroke lasting 20 minutes, Yepes and his colleagues found. In the laboratory, pre-treatment with tPA protects hippocampal neurons in culture from hypoxia. In contrast, tPA has the opposite effect on neurons from the cortex.

tPA's protective properties suggest that it may be playing a role in a process called "ischemic preconditioning," where a less-than-lethal stroke can protect the brain against a later repeat, Yepes says. tPA's effects on the blood-brain barrier can be seen as a way to get more blood to a deprived part of the brain.

In most people who experience a stroke, atherosclerosis has gradually restricted blood flow over a long time period, provoking attempts by the brain to work around the obstacle.

"Many individuals who have a transient ischemic attack, which is a non-lethal mini-stroke, go on to have a more serious and debilitating stroke," Yepes says. "This means we should be thinking about tPA less as a way of treating ischemic stroke but more as a way to prevent it."

One way to use tPA preventively could be to prolong the effects of tPA produced naturally in the brain, a strategy Yepes and his colleagues are investigating now. They are also probing which molecules in neurons are necessary for the protective effects of tPA. tPA appears to be acting on a class of neurotransmitter receptors known as NMDA receptors, they show in the paper.

The research was supported by the National Institutes of Health.


Story Source:

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


Journal Reference:

  1. Echeverry et al. Tissue-type plasminogen activator is a neuroprotectant in the mouse hippocampus. Journal of Clinical Investigation, 2010; DOI: 10.1172/JCI41722

Cite This Page:

Emory University. "Brain may use clot-busting drug naturally as protection against stroke." ScienceDaily. ScienceDaily, 6 May 2010. <www.sciencedaily.com/releases/2010/05/100503174018.htm>.
Emory University. (2010, May 6). Brain may use clot-busting drug naturally as protection against stroke. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2010/05/100503174018.htm
Emory University. "Brain may use clot-busting drug naturally as protection against stroke." ScienceDaily. www.sciencedaily.com/releases/2010/05/100503174018.htm (accessed April 21, 2014).

Share This



More Mind & Brain News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Study On Artists' Brain Shows They're 'Structurally Unique'

Study On Artists' Brain Shows They're 'Structurally Unique'

Newsy (Apr. 17, 2014) The brains of artists aren't really left-brain or right-brain, but rather have extra neural matter in visual and motor control areas. Video provided by Newsy
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. 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:
from the past week

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