Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Duke Researchers Link Nitric Oxide, Vessel Health

24.11.2003


Jason Allen, Ph.D., conducting a study of the brachial artery in the arm
PHOTO CREDIT: Duke University Medical Center


Duke University Medical Center researchers have shown an association between changes in nitrate, a biochemical marker of nitric oxide production, and physiological changes in arteries’ reaction to stress. They hope their discovery could eventually lead to a non-invasive method of determining which patients are at risk for developing cardiovascular disease.

Such a simple diagnostic is important, they said, because up to half of patients who develop heart disease do not have the typical risk factors. Furthermore, using this new approach, the researchers demonstrated that exercise improved the marker in patients at risk for developing cardiovascular disease.

In their pilot study, the researchers linked the systemic production of nitric oxide, a chemical known to play a key role in controlling the ability of arteries to constrict or relax, with changes in the endothelial lining of arteries after being stressed.



"This is the first study to attempt to link whole body production of nitric oxide with regional endothelial function," said Jason Allen, Ph.D., who presented the results of the Duke study today (Nov. 22, 2003) during the 10th annual scientific sessions of the Society for Free Radical Biology and Medicine. "Both measures were found to discriminate between healthy participants and those with diagnosed cardiovascular disease."

In addition to its ability to dilate arteries, nitric oxide has other properties that protect against cardiovascular disease, such as inhibiting blood platelet clumping, preventing smooth muscle proliferation within the artery and inhibiting the immune response.

On the other hand, other risk factors, such as diabetes, high blood pressure, mental stress and smoking can reduce nitric oxide’s protective properties, said the researchers. It is believed that these patients produce more oxygen free radicals, impairing the ability of the body to respond appropriately to nitric oxide. These oxygen free radicals are highly reactive chemicals that are the potentially destructive byproducts of the disease process.

In their experiments, the researchers divided 37 participants into three groups – healthy (12), those who had two or more identified risk factors but without clinical diagnosed cardiovascular disease (15), and those with known disease (10).

To determine how arteries responded physiologically under different circumstances, Allen used ultrasound to visualize the brachial artery, the major artery of the arm. The ultrasound images can then be analyzed to detect even the slightest changes in the diameter of the artery.

The researchers made detailed measurements at three time points – baseline, while the artery was being occluded by a tourniquet, and after the tourniquet was released.

"When the tourniquet is loosened, the resulting increased blood flow causes physical shear stress to the endothelium," Allen explained. "A healthy artery should be able to react to the increased blood by dilating. Conversely, an unhealthy or diseased artery will not be able to respond as well. This response of the endothelium is regulated in part by nitric oxide."

While the diameters of arteries in all three groups increased, the healthy group saw the largest percentage increase after 60 seconds, possibly indicating greater endothelial health and nitric oxide production.

To better understand the biochemical responses in the patients, Allen then took blood samples from all the participants at rest, immediately following a strenuous exercise test, and then ten minutes after exercise completion.

"The group of healthy participants was the only one that saw an increase in systemic nitric oxide during the recovery period after exercise," Allen explained. "We also found that the reactivity of the brachial artery was greater in the healthy patients when compared to those with cardiovascular disease."

Allen then sought to discover whether a sustained program of exercise had any effect on nitric oxide production and reactivity of the brachial artery. So, he followed seven of the participants in the "at-risk" group during six months of exercise carried out on cycle ergometers, treadmills or elliptical trainers in a supervised setting. After six months, the researchers performed the same series of ultrasound and biochemical tests again.

After the exercise period, the at-risk patients had a significant increase in nitric oxide metabolite production during the recovery period after exercise, as well as an almost doubling of the brachial artery reactivity, Allen said.

"First, it appears that a nitric oxide metabolite measured in the blood after exercise may discriminate between healthy patients and those with cardiovascular disease and is related with a physiological response of the artery diameter," Allen said. "Also, these biochemical and physiological markers can be positively influenced by exercise in patients who are at risk for cardiovascular disease."

This pilot project was funded by Duke’s division of cardiology. Joining Allen was Frederick Cobb, M.D., from Duke, and Andrew Gow, Ph.D., Children’s Hospital of Philadelphia.

Richard Merritt | dukemed news
Further information:
http://dukemednews.org/news/article.php?id=7211

More articles from Health and Medicine:

nachricht Serious children’s infections also spreading in Switzerland
26.07.2017 | Universitätsspital Bern

nachricht New vaccine production could improve flu shot accuracy
25.07.2017 | Duke University

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: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>