Introduction:: Exposure to elevated ambient ozone levels has been associated with exacerbation of asthma, likely mediated by oxidative stress. We have shown that supplementation with the antioxidant vitamin E isoform, gamma tocopherol, mitigates the inflammatory effects of inhaled endotoxin exposure, a key component of ambient air particulate matter.
Objective:: The objective of the current study was to assess the efficacy of gamma tocopherol for mitigating pulmonary effects of ozone, using an abbreviated dosing regimen that could be rapidly begun when high ozone days are anticipated.
Materials and Methods:: We conducted a randomized, double blind, placebo-controlled crossover study of adults with mild asthma who were pre-treated with gamma tocopherol-enriched supplement and exposed to 0.25 ppm ozone for 3 hours. Induced sputum samples were obtained before and after ozone exposure to measure airway inflammation. Mucociliary clearance was estimated using gamma scintigraphy.
Results:: With the short course of gamma tocopherol pre-treatment, we found no significant effect on ozone-induced airway inflammation. A transient slowing of clearance in the large airways was seen following ozone exposure in the placebo treatment period that was not present during gamma tocopherol treatment.
Discussion:: Short course gamma tocopherol did not protect against ozone-induced airway inflammation. Future work will focus on the efficacy of longer courses of gamma tocopherol supplementation for mitigating pollutant-induced health effects. The early transient ozone effect on airway clearance as well as the impact of gamma tocopherol on this effect will be further explored in future studies.