Lung :: Carbon monoxide protects lung cells against oxygen-induced damage
Researchers at the University of Pittsburgh have demonstrated that low-dose carbon monoxide administered in conjunction with oxygen therapy markedly inhibits oxygen-induced damage to lung cells. These findings, being reported in the Jan. 19 issue of the Journal of Biological Chemistry, have significant implications for the treatment of acute respiratory distress syndrome, or ARDS, according to the study’s authors.
ARDS is a life-threatening medical condition in which patients experience severe shortness of breath and oxygen starvation. Although ARDS often occurs in people who have lung disease, even people with normal lungs can develop the condition as the result of severe trauma or an infection. Without prompt treatment, the oxygen deprivation resulting from ARDS can be lethal. Even with appropriate treatment, however, about 30 to 40 percent of all people with severe ARDS die from the condition. In fact, it is the number one killer of patients in intensive care unit facilities in the United States.
Treatment for ARDS primarily involves hooking the patient up to a mechanical ventilator and giving them almost pure oxygen (95 percent oxygen and 5 percent carbon dioxide). However, recent studies in animals have shown that prolonged exposure to an elevated level of oxygen, or hyperoxia, can cause long-term lung injury that resembles ARDS.
“Giving ARDS patients almost pure oxygen over a prolonged period may be a double-edged sword,” said lead investigator Augustine Choi, M.D., professor of medicine and the chief of the division of pulmonary, allergy and critical care medicine at the University of Pittsburgh School of Medicine. “It saves their life in the short term, but long-term exposure appears to cause significant damage to many cell types including the epithelial and endothelial cells of the lung. However, by administering oxygen mixed with a very small amount of carbon monoxide, we may be able to significantly reduce such oxygen-associated damage and cell death.”