Protective Effects of Sodium Nitrite Explored

An animal study has found that sodium nitrite may be useful for protecting and preserving tissue and organ function after heart attack, high-risk abdominal surgery, and organ transplantation.

Sodium nitrite is a naturally occurring chemical, commonly used as a meat preservative and to treat cyanide poisoning. In a study published in the May 2005 issue of The Journal of Clinical Investigation, scientists found that low concentrations of sodium nitrite had a strong protective effect, preventing cell death in the hearts and livers of mice undergoing experimental heart attack and liver injury. An earlier study had shown that infusions of sodium nitrite into the human circulation leads to the production of nitric oxide (NO), a strong blood vessel dilating molecule that increases blood flow.

In the current study, the researchers compared the effects of both lower and higher concentrations of nitrite versus control treatments of saline or nitrate, which is related to nitrite but cannot convert to NO. They found that only low concentrations of nitrite provided protection against injury and believe the protective effect is related in some way to the conversion of nitrite to nitric oxide.

"The remarkable thing about nitrite is that it is only converted to nitric oxide in the organs and tissues with the lowest oxygen levels, allowing for targeted NO delivery--and thus improved blood flow--to tissues under stress,” explained Dr. Mark Gladwin, head of the vascular therapeutics section of the cardiovascular branch of the U.S. National Heart Lung Blood Institute (NHLBI, Bethesda, MD, USA), co-leader of the study. "More research is needed to look at the effectiveness of nitrite in various organs and disease states in humans.”

Dr. Gladwin is currently studying the use of sodium nitrite as a way to help adults with sickle cell disease, by reversing the effect of decreased blood flow due to patients' "sickled” blood cells. Other studies are planned or under way to evaluate the effect of sodium nitrite on heart attacks, kidney failure, solid organ transplantation, cerebral vasospasm, and high blood pressure in the lungs of babies.




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