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 Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

nachricht Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>