RESUMO
Objective To invesitgate the relationship between 8-iseprostane (8-iso-PG) level in exhaled breath condensates (EBCs) and severity of asthma and explore the role of 8-iso-PG in asthma evaluation and monitoring.Methods Fifty-nine patients with asthma were enrolled.In which 15 eases were acute exacerbation, 13 eases were mild intermittent, 15 eases were mild persistent, and 16 eases were mederate-to-severe persistent.Thirteen healthy volunteers were recruited as control.EBCs were collected using EeoSereen system.The 8-iso-PG levels in EBCs were measured by a specific enzyme immunoassay.The patients with mild intermittent asthma were treated with inhaled corticosteroid (ICS) for one month and their EBCs were recollected for 8-iso-PG measurement.Results Exhaled 8-iso-PG levels were obviously increased in the patients with acute asthma compared with those chronic asthmatics [(47.2±6.8) pg/mL vs (24.5±12.0) pg/mL, P < 0.01].In the chronic persistent asthma, the levels were significantly higher in patients with mild persistent and moderate-to-severe asthma [(17.9±1.2) pg/mL and (39.7±4.0) pg/mL, P <0.01].While 8-iso-PG level did not differ significantly in intermittent asthma [(13.5±1.1) pg/mL] compared with the control subjects (P > 0.05).After one-month ICS treatment the 8-iso-PG level in the patients with mild intermittent asthma did not change significantly although the ACT score improved.Conclusions 8-iso-PG levels in EBC are associated with the severity of asthma,implicating 8-iso-PG may be useful in monitoring airway oxidative stress in asthma.ICS treatment is incapable of decreasing the 8-iso-PG,suggesting the ICS has minor impact on oxidative stress.