Carbon monoxide is a quiet assassin. Odorless and colorless, it has a uniquely efficient ability to starve the body of oxygen: It acts quickly, building up in the bloodstream and attaching to hemoglobin in oxygen’s place. When that happens, red blood cells can’t pick up oxygen to carry around the body, and the organs effectively suffocate.
This gas, a common by-product of incomplete fuel combustion, causes 50,000 to 100,000 emergency room visits and 1,500 deaths in the U.S. every year on average. Typical treatment for carbon monoxide poisoning calls for using an oxygen mask or hyperbaric chamber to suffuse the body with oxygen, weakening carbon monoxide’s bond with hemoglobin cells so oxygen can attach instead. It works, but it’s slow—and although only a small percentage of people with carbon monoxide poisoning die, survivors are often left with brain damage, cardiac complications, or kidney and liver problems from oxygen deprivation.
But recent research suggests a faster antidote. A study in the Proceedings of the National Academy of Sciences USA documents a newly engineered protein therapy called RcoM-HBD-CCC; when given intravenously to mice, it was shown to cling to carbon monoxide, letting the kidneys expel the poison within minutes.
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“We want a treatment that you can give in the field,” says study co-author Mark T. Gladwin, dean of the University of Maryland School of Medicine. He says RcoM-HBD-CCC could be injected into people on their way to the hospital in an ambulance or given to people with low oxygen levels at the site of indoor fires.
“This molecule becomes bound to carbon monoxide pretty much as soon as you inject it,” says study co-author Jesus Tejero, a biochemist at the University of Pittsburgh. Because it has a much higher affinity for carbon monoxide than carbon monoxide has for hemoglobin, RcoM-HBD-CCC rapidly sponges up the toxic gas. In addition to the mouse study, the researchers also confirmed that the protein quickly clings to carbon monoxide in test tubes with human blood.
Lance B. Becker, an emergency medicine researcher at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, who was not involved in the study, notes that the new protein binds to carbon monoxide but not to nitric oxide, a gas molecule that plays a key role in relaxing blood vessels to improve circulation. Gladwin and his team had previously engineered a protein with an affinity to carbon monoxide—but it also bound to nitric oxide, causing problematic artery stiffening in early tests in mice.
Becker hopes this treatment will prove effective in planned studies with larger animals and eventually in human trials, which are probably still a few years off. Although researchers won’t know whether it works in human bodies until they try it, Becker is optimistic. “It’s a very clever little molecule if it pans out,” he says.