Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discovery changes ideas about damage from strokes

13.01.2004


In experiments in the laboratory and with mice, the Johns Hopkins researchers found that the chemical prostaglandin-E2 protects brain cells from damage. The finding was completely unexpected, the researchers say, because prostaglandin-E2 causes damage in other tissues and is made by an enzyme, COX-2, known to wreak havoc in the brain after injury. The findings appear in the Jan. 7 issue of the Journal of Neuroscience.



"It’s kind of paradoxical, that the product of an enzyme that causes damage is itself beneficial," says Katrin Andreasson, M.D., an assistant professor of neurology and of neuroscience. "It’s possible that future treatments for stroke might use drugs to block COX-2 and enhance the effects of prostaglandin-E2, providing sort of a double whammy of protection.

"Prostaglandins have not previously been implicated in reducing damage from stroke, so our finding provides a completely new strategy for tackling and understanding the condition," she adds.


In experiments with individual brain cells and with brain slices from mice, the researchers discovered that prostaglandin-E2 (PGE2), one of many related molecules created by COX-2, protects brain cells traumatized by over-stimulation or by insufficient oxygen. Furthermore, in genetically engineered mice lacking one of the receptors, or docking points, for this prostaglandin, stroke damage was much greater than in normal mice, the researchers report.

"Together, these results provide very strong evidence that PGE-2 is indeed protective in the brain even though it may not be elsewhere in the body," says Andreasson, who obtained the genetically engineered mice from Richard Breyer at Vanderbilt University School of Medicine.

After their surprising discovery, the research team searched for why PGE2 is a "good guy" in the brain. Their experiments showed that stimulation of PGE2’s receptor increases production of a molecule called cyclic-AMP, which is known to help the brain. Other effects of PGE2, such as anti-inflammatory effects, may also contribute to its protective abilities in the brain, says Andreasson.

"We think that COX-2 products that increase cyclic-AMP may prove to be protective, like PGE2, while those that lower cyclic-AMP may contribute to COX-2’s known negative effects on brain damage from stroke," she says. "We’re still working on it."

About 4 million Americans are currently living with the effects of stroke, in which blood flow and oxygen delivery to the brain are interrupted by blockage or breakage of a blood vessel. At first, brain cells are shocked, not killed, but their chances of recovery decrease rapidly as time passes.

If given within an hour of the stroke, a drug called t-PA can prevent extensive damage by dissolving the blood clot that caused the stroke. However, finding a way to intervene later on -- for patients whose symptoms aren’t immediately recognized or who are more than an hour from a hospital -- could dramatically improve recovery and reduce the financial burden of strokes, which the National Stroke Association estimates is roughly $43 billion per year in the United States.

"We still need to determine whether stimulating the PGE2 receptor hours after a stroke can protect mice from damage," says Andreasson, who is conducting some of those studies now. "If so, pursuing this prostaglandin as a potential clinical target will be of great importance."

COX-2 has a significant role in brain damage after stroke in mice, and Andreasson has been searching for how exactly COX-2 causes damage. Scientists know that COX-2 is involved in creating inflammation, or swelling (drugs like Celebrex and Vioxx inhibit COX-2 and are widely prescribed for arthritis and other inflammatory conditions), but its activity leads to the production of a number of different molecules which could be more directly responsible for its effects. Andreasson and her colleagues are continuing to evaluate the effects of other products of COX-2.


The studies were funded by the American Federation for Aging Research, the American Heart Association, and the National Institute on Neurological Diseases and Stroke. Authors on the report are Andreasson, Louise McCullough, Liejun Wu, Norman Haughey, Xibin Liang, Tracey Hand and Qian Wang of The Johns Hopkins University School of Medicine; and Breyer of Vanderbilt.

Joanna Downer | EurekAlert!
Further information:
http://www.jneurosci.org/
http://www.hopkinsmedicine.org/

More articles from Health and Medicine:

nachricht Energizing the immune system to eat cancer
22.01.2019 | University of Pennsylvania School of Medicine

nachricht Early Prediction of Alzheimer’s Progression in Blood
22.01.2019 | Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE)

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Bifacial Stem Cells Produce Wood and Bast

Heidelberg researchers study one of the most important growth processes on Earth

So-called bifacial stem cells are responsible for one of the most critical growth processes on Earth – the formation of wood.

Im Focus: Energizing the immune system to eat cancer

Abramson Cancer Center study identifies method of priming macrophages to boost anti-tumor response

Immune cells called macrophages are supposed to serve and protect, but cancer has found ways to put them to sleep. Now researchers at the Abramson Cancer...

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

How our cellular antennas are formed

22.01.2019 | Life Sciences

Proposed engineering method could help make buildings and bridges safer

22.01.2019 | Architecture and Construction

Bifacial Stem Cells Produce Wood and Bast

22.01.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>