Nitrite Improves Blood Flow

http://www.usmedicine.com/dailyNews.cfm?dailyID=183

Scientists at the National Institutes of Health (NIH) have determined that nitrite, a common small ion, or salt, in blood, can improve blood flow by opening blood vessels. This increases oxygen in the blood and makes it a potential new treatment for diseases, such as high blood pressure, heart attacks, sickle cell disease, and leg vascular problems.

The study also describes a newly discovered function for the hemoglobin molecule, itself, perhaps the most studied protein in human history. The new study demonstrates that when hemoglobin releases its oxygen in regions of the body with low oxygen, such as organs, or high metabolism, it can then convert nitrite to nitric oxide, which is known to dilate blood vessels.

The results of the study were published in the December 2003 issue of Nature Medicine.

"The importance of this work is that no one considered this molecule to have any significant function, and it is relatively abundant in the bloodstream," said Dr. Mark Gladwin, senior investigator in Critical Care Medicine Department of the NIH Clinical Center and an author of the article.

Nitrite levels have been shown to be low in patients with high blood pressure.

Dr. Gladwin and co-author Dr. Richard Cannon, III, in the Cardiovascular Branch of the National Heart, Lung and Blood Institute (NHLBI), studied 18 healthy volunteers who were enrolled in a physiological study. They were infused with sodium nitrite to determine whether nitrite affects blood flow. They showed that blood flow increased by 175 per cent.

"We saw huge improvement in blood flow," said Dr. Gladwin. "Nitrite helps get more blood to regions of the body with low oxygen, such as kidneys, the heart, the brain and muscles. This has potential as a new therapy that was previously overlooked. It's a powder sitting on the shelf and everyone has it."

Dr. Gladwin warns, however, that at high concentrations it can be toxic and clinical trials, now in progress at NIH, are required to establish its clinical usefulness in various diseases.