Research Finds New Cause of Ozone Wheezing and Potential Treatments
Ozone has been estimated, in an Environmental Protection Agency analysis, to cost the United States $5 billion a year as a result of premature deaths, hospitalizations and school absences. Inhalation of ozone can lead to irritation of the airways and increased wheezing, particularly in children and adults who have asthma and chronic obstructive lung disease.
Balintfy: Researchers have discovered a cause of airway irritation and wheezing after exposure to ozone, a common urban air pollutant. These findings help identify potential new targets for drugs which may eventually help physicians better treat emergency room patients suffering from wheezing, coughing and shortness of breath. Dr. Stavros Garntziotis is a principal investigator at the National Institute of Environmental Health Sciences.
Dr. Garantziotis: The connection between ozone and the mechanism that leads to wheezing and airway irritation has not been very clear. And what we have found using a mouse model is that the connection may actually have to do with a naturally occurring sugar in the body which is called hyaluronan.
Balintfy: Dr. Garantziotis explains that it is not ozone itself that causes the body to wheeze, but the way the lungs respond to ozone.
Dr. Garantziotis: Now, as I've said, hyaluronan is a naturally occurring sugar, only in a healthy person it's usually found in a long-chain form. So it's occurring in long chains. What we have found if we expose mice to ozone to similar concentrations that would, for example, be found or a person would be exposed in a high ozone day, we find much more hyaluronan in the airways. But even more importantly, we find that instead of the long-chain hyaluronan, we find a short-chain hyaluronan. That seems to be directly causing airway hyper-responsiveness, meaning irritability of airways and the equivalent of wheezing, in other words.
Balintfy: Dr. Garantziotis adds that there are at least two ways that these findings could potentially lead to treatment options for the patients that have been exposed to ozone and have shortness of breath symptoms.
Dr. Garantziotis: For one, we could bind hyaluronan away using a hyaluronan-binding protein and that completely abolished the airway hyper-responsiveness and airway irritation. We also were able to give the long-chain—the naturally occurring hyaluronan, if you will—as a competitor, and that seemed to counteract the effects that we observed after ozone exposure.
Balintfy: Ozone is formed in the inner atmosphere in the presence of sunlight from pollutants emitted from vehicles and other sources. Exposure occurs when people inhale air containing ozone. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.
About This Audio Report
Reporter: Joe Balintfy
Sound Bite: Dr. Stavros Garantziotis
Topic: airway irritation, asthma, pollution, ozone