By AMERICAN HEART ASSOCIATION NEWS
Sage Wiener, M.D., has taken care of dozens of people with carbon monoxide poisoning as an emergency medicine doctor in Brooklyn. He’s relied on oxygen to alleviate the headaches, dizziness, vomiting and other symptoms – a strategy that hasn’t changed much in recent decades.
But Wiener is heartened by new research that shows a protein might help people expel the poison and recover faster, mitigating potential damage to the heart, kidneys and other organs.
Carbon monoxide is an odorless, colorless gas produced when fuel isn’t burned completely in furnaces, boilers, engines and other heat-generating sources. When ingested, it chokes off the oxygen supply in the blood. Even relatively low levels of the gas can be harmful for people with cardiovascular disease.
At the University of Pittsburgh Medical Center, critical care doctor and the study’s senior author Mark T. Gladwin, M.D., has seen what severe carbon monoxide poisoning can do. His interest in finding an antidote led him to study neuroglobin, a compound belonging to a family of proteins that bind or transport oxygen in the body.
Neuroglobin was discovered 17 years ago, but Gladwin said scientists don’t know what it does.
“We make mutations in it to try to understand its function by making it change its function to see what it does,” said Gladwin, chair of the university’s department of medicine and director of the Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute. “And that’s how we stumbled into this idea” that it could help treat carbon monoxide poisoning.
He and his fellow investigators changed the protein’s molecular structure to make it powerfully latch on to carbon monoxide and injected it into mice with lethal levels of the gas.
Gladwin said the mutated neuroglobin worked like a magnet, pulling the toxic gas off oxygen-rich hemoglobin that helps keep our tissues and organs healthy. The mutated protein bound itself 500 times more tightly to carbon monoxide than hemoglobin.
Surprisingly, Gladwin said, it only took about 25 seconds for half of the carbon monoxide in the blood to bind to the neuroglobin. By comparison, it takes about 70 minutes for a person with mild poisoning given a breathing treatment of 100 percent oxygen to get rid of half of the noxious gas inhaled, he said. Someone with high levels of poisoning treated with oxygen in a high-pressure chamber takes about 20 minutes to get rid of half the carbon monoxide.
Wiener said most poisons cannot be removed from the body, so being able to target carbon monoxide would be effective.
In 2015, there were 393 deaths from accidental carbon monoxide poisoning, according to data from the Centers for Disease Control and Prevention. About 50,000 Americans visit an emergency room each year due to accidental carbon monoxide poisoning, research shows.
Thorsten Burmester, Ph.D., is the researcher who discovered neuroglobin. He said the results of the study are important because “the authors developed the first true application” for the protein.
Burmester, of the University of Hamburg in Germany, was surprised the compound could bind to carbon monoxide with such great strength. The findings open up a new field of research, he said.
But the verdict is still out on whether the treatment will work in humans, said longtime medical toxicologist Steven Aks, D.O., an emergency medicine physician at Cook County Health & Hospitals System’s Stroger Hospital in Chicago who wasn’t involved with the research.
Mice in the study were treated immediately after being exposed to carbon monoxide. Yet many patients exposed to the gas may not get medical treatment until an hour or more after exposure, Aks said.
“Really, the next questions are, does it work on a delayed basis and can we get it into people without causing any harm?” Aks said.
It will likely be two years before researchers start testing the neuroglobin solution in humans, Gladwin said.
Until then, experts urge people to learn how to prevent carbon monoxide exposure, such as never using a gas range or oven to heat the home, never leaving a car running in an enclosed space such as a garage, and installing carbon monoxide detectors in the home.
The study was published in December in Science Translational Medicine.