July 21, 2000

Inhalation of nitric oxide (NO) gas may prevent the development of pulmonary vascular disease (PVD), a dangerous condition that can affect about one of every 500 infants. In the July issue of Circulation Research, MGH investigators report that inhaled NO kept infant rats with lung injuries from developing PVD by interfering with the basic process underlying the disorder, an overgrowth of cells in the walls of the pulmonary arteries. There currently is no way to prevent PVD in at-risk infants, and treatments for the condition are not very effective.

"Nitric oxide therapy has the potential to significantly increase the quality of life and – in some cases – save the lives of infants at risk for PVD," says Jesse D. Roberts, MD, right, of MGH Anesthesia and the MassGeneral Hospital for Children, the paper's first author. "With these findings and the knowledge that nitric oxide is a very safe treatment for other lung conditions, the time is right to design clinical trials in human infants."

PVD can develop in infants when damage to the lungs – caused by the use of ventilators to support premature lungs, lung inflammation or stresses imposed by congenital heart defects – induces the walls of vessels carrying blood between the heart and lungs to thicken. The condition can lead to heart failure, delays in normal growth and development, or even death.

MGH anesthesiology researchers pioneered the study of inhaled NO to treat serious lung disease. In the current study, the researchers injected a group of newborn rats with an agent known to cause lung injury and PVD. Rats that continuously breathed a mixture of air with a small amount of NO throughout the two-week study showed no symptoms of PVD, while rats not receiving NO had significant overmuscularization of their lung arteries.

Other authors of the study are Kenneth Bloch, MD, of the MGH Division of Cardiology and the Cardiovascular Research Center (CVRC); Jean-Daniel Chiche, MD, of the CVRC; and Joerg Weimann, MD, Wolfgang Steudel, MD, and Warren Zapol, MD, of the Department of Anesthesia and Critical Care.