New York, NY - April 27, 2001 -- A toxic component of industrial emissions, exhaust and cigarette smoke, carbon monoxide starves our cells of oxygen by replacing oxygen molecules in the blood. Exposure to carbon monoxide can have fatal consequences. But surprisingly, according to a new study by Columbia University researchers, carbon monoxide may also have a life-saving effect when blood vessels are blocked, such as during heart attack or stroke. The results "point to potential therapeutic uses for inhaled carbon monoxide," the study's authors say. The paper is published in the May issue of Nature Medicine.
Lead author David J. Pinsky, M.D., associate professor of medicine at the Columbia University College of Physicians & Surgeons, also has signaled a need for caution. "There's more work that needs to be done to identify the conditions under which this is useful and the doses that are safe," he said. "Like many other molecules that are beneficial in the right doses, too much of them can have a lethal effect."
Carbon monoxide (CO) appears to help restore blood flow to organs threatened with a cut off blood supply, according to the authors. It does so by enhancing the body's own clot-dissolving mechanisms and by dilating blood vessels. The researchers demonstrated the results in mice.
At lower than lethal doses, it seems, "CO can paradoxically either imperil or salvage tissue by disparate mechanisms," the authors report.
The body itself produces carbon monoxide when a part of the organism becomes oxygen-starved due to blood vessel blockage, a condition called ischemia. The carbon monoxide is created as part of a natural process in which an enzyme called heme oxygenase type 1 breaks down vital molecules called hemes, when the cells carrying them wear out.
Through as-yet poorly understood mechanisms, heme oxygenase type 1 levels rise during ischemia, stepping up this process and increasing carbon monoxide levels.