Cysteinyl-Leukotrienes, 8-isprostane And PH In Exhaled Breath Condensat Of Patients With Asthma

Objective:The aim of this study is to try to determine whether Cysteinyl Leukotrienes(cys-LTs)cys-LTs,8-isprostane and pH in EBC,which is a noninvasive method of sampling airway secretions,could be used as a marker of airway inflammation,oxidative stress and.endogenous airway acidification by evaluating the levels of cys-LTs,8-isprostane and pH in the Exhaled breath condensate(EBC)of patients with different degrees of asthma severity and assessing the relationship between the above markers and severity of disease.Furthermore,the relationship between the mediatores and the effect on the marker of inhaled steroids were studied.Methods:(1).Fifty-nine patients,including 15 width acute asthma,44 with nonacute asthma (13 intermittent,15 mild persistent,and 16 moderate-to-severe persistent)and 13 healthy controls were recruited.Exhaled breath condensate(EBC)was collected from each group using EcoScreen.Cys-LTs and 8-isprostane in EBC was measured by a specific enzyme immunoassay,pH was measured by microelectrode pH meter after deaeration of EBC samples by bubbling with argon.Pulmonary function test were also performed and asthma control test were administrated.(2).Inhaled Fluticasone were administrated to subjects with mild persistent asthma (Flixotide 250ug/d)for 3 months,all test and biomakers above were performed and analyzed.Comparing the differences of such indexes between two groups and the control.Results:(1).Cys-LTs and 8-isprostane levels were detectable in breath condensate of healthy controls and patients.Cys-LTs and 8-isprostane in EBC were increased in patients with asthma than healthy and lower pH values were observed in the EBC of asthmatic patients compared to control subjects.Furthermore,the levels of the biomakers in EBC are associated with the severity of asthma. (2).In all of the subgroups of patients with asthma,there were significant positive correlation between Cys-LTs and 8-isprostane and negative correlation between Cys-LTs and pH,but there were no correlation between FEV₁%and Cys-LTs as well as 8-Isoprostane.(3).Exhaled pH of mild persistent subjects increases significantly and trended towards control levels after treatment with inhaled steroids for 3 months while it did not after 1 month and levels of the cys-LTs and 8-Isoprostane were not reduced by inhaled glucocorticoid one month treatment.Conclusions:(1).Being a noninvasive measurement,collecting EBC is an easy and feasible process. Some notable variances of biomarkers in EBC can be detected correlating with asthma,and the severity of disease as well.The measurement of cys-LTs,8-isprostane and pH in EBC may prove to be useful in screening and monitoring inflammation, endogenous acidification and oxidantive stress in airway of patients with asthma.(2).Our study shows cys-LTs and 8-Isprostane in EBC are increased and pH are decreased in patients with asthma.These findings suggest that inflammation, oxidantive stress and endogenous airway acidification are characteristic in patients with asthma.(3).There were significant correlation between these biomarkers imply that oxidantive stress,endogenous airway acidification and inflammatory have effect on each other.(4).Endogenous airway acidification can be controlled by administrated inhaled Fluticasone,but the dose of inhaled corticosteroids used in our study was sufficient to control clinical symptoms but maybe not sufficient to completely suppress the inflammatory processes and oxidantive stress for these biomarkers seem to show a certain degree of resistance to steroid treatment.