Nitrite Therapy for Babies with Pulmonary Hypertension

A study has found that an inhaled nitrite spray can rapidly reduce persistent pulmonary hypertension of the newborn (PPHN) in an animal model.

Premature newborns and those with pneumonia or heart problems frequently develop PPHN, an often-fatal disease that causes high blood pressure in an infant's lungs and places the baby in a low-oxygen state. Researchers at the U.S. National Institutes of Health (NIH; www.nih.gov) decided to try a nitrite spray in an animal model. Nitrite dilates blood vessels in the lungs, reacts with de-oxygenated hemoglobin, and is converted into nitric oxide when the body is in a low-oxygen state. Nitric oxide (NO) helps to regulate blood flow, so the researchers thought the naturally occurring conversion of nitrite to nitric oxide might help babies with PPHN by lowering lung blood pressure and raising oxygen levels.

"Nitrite inhalation rapidly reduced pulmonary pressures by 65%,” said Christian Hunter, Ph.D., a fourth-year medical student at Loma Linda University School of Medicine (CA, USA). "The nitrite had a much longer effect than the nitric oxide. In one case, we administered the inhaled nitrite for 20 minutes and the high blood pressure levels were reversed for an hour.”

The researchers mixed nitrite with plain saline solution, and administered it with a plastic inhaler. They note that more research is needed to determine the safety and efficacy of inhaled nitrite for human use. The study results were reported in the September 12, 2004, online edition of Nature Medicine.





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