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Controlled exposure of healthy young volunteers to ozone causes cardiovascular effects**
Citation:
Devlin, R., K. Duncan, M. Jardim, M. Schmitt, AND D. Diaz-Sanchez. Controlled exposure of healthy young volunteers to ozone causes cardiovascular effects**. CIRCULATION. Editorial Garsi SA, Barcelona, Spain, 126(1):104-11, (2012).
Impact/Purpose:
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Description:
Background: Recent epidemiology studies have reported associations between acute ozone exposure and mortality. Such studies have previously reported associations between airborne particulate matter pollution (PM) and mortality and support for a causal relationship has come from controlled exposure studies which describe pathophysiological mechanisms by which PM could induce acute mortality. In contrast, for ozone, to date, there are almost no clinical studies which have tested whether ozone exposure can modulate the cardiovascular system. Methods and Results: 23 young healthy individuals were exposed in a randomized crossover fashion to clean air and 0.3 ppm ozone for two hours while undergoing intermittent exercise. Blood was obtained immediately prior to exposure, immediately afterward, and the next morning. Continuous Holter monitoring began immediately prior to exposure and continued for 24 hours. Lung function was performed immediately prior to and immediately after post exposure and bronchoalveolar lavage was performed 20 hours after exposure. Several markers of vascular inflammation (interleukin-IB, interleukin-8, tumor necrosis factor c, C reactive protein) were increased following ozone exposure. Ozone also induced changes in proteins involved in the fibrinolytic pathway (tissue plasminogen factor, plasminogen activator inhibitor, plasminogen). In addition, ozone induced decreases in the frequency domain ofheart rate variability, as well as a lengthening ofthe QT interval. In agreement with previous studies, we also observed ozone-induced drops in lung function and an increase in pulmonary inflammation. Conclusions: This is the first controlled human exposure study to show that ozone can cause changes in both the cardiac and vascular systems and provides biologic plausibility for the epidemiology studies that associate ozone exposure with mortality. Key Words: fibrinolysis; inflammation; nervous system, autonomic Clinical Trial Registration Information: NCT