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RELATIONSHIP BETWEEN INDUCED OXIDENT GENERATION AND ASTHMA SEVERITY
Citation:
Yeatts, K. B., E. Svendsen, B. Heidenfelder, J Inmon, R B. Devlin, L Neas, P A. Bromberg, D. B. Peden, AND J Gallagher. RELATIONSHIP BETWEEN INDUCED OXIDENT GENERATION AND ASTHMA SEVERITY. Presented at American Thoracic Society Annual Meeting, San Diego, CA, March 20 - 25, 2005.
Description:
The role of oxygen radicals is implicated in many disease processes, including asthma. There is evidence that elevated oxidant status is associated with airway hyper responsiveness, however it is less clear whether increased levels of circulating reactive oxygen species are associated with increased severity of asthma. Methods: We analyzed oxidant levels in 108 blood and plasma samples from 12 asthmatic individuals drawn over a 6 week period (daily for four days and then once per week for five additional weeks). We measured oxidants both in plasma and whole blood and measured the increase in the intensity of oxidant activation by whole blood stimulation with phorbol 12-myristate 13-acetate (PMA). Oxidant levels in plasma and whole blood were measured by luminol-dependent chemiluminescence. Asthma severity was classified using NHLBI guidelines. Results: Inter-individual variation in oxidant levels was significantly greater than intra-individual variation (plasma, p<0.001; blood with PMA, p<0.001). The strongest mean plasma chemiluminescent response was associated with an individual with the highest asthma severity score. A statistically significant correlation (Pearson's correlation coefficient r =.68, p=0.02) between asthma severity and oxidant generation induced by whole blood PMA stimulation was found. Plasma oxidant levels alone and asthma severity were less strongly correlated (r=.45, p=.16). Conclusions: The relationship between asthma severity and oxidant generating capacity of whole blood suggests that circulating oxidants may be indicative of site specific asthmatic airway inflammation. Oxidant measurement may have useful clinical implications for investigating phenotype differences among asthmatic patients. These findings do not necessarily represent EPA policy. Funding: EPA Cooperative Agreement 829522, NHLBI R01HL62624