Exhaled nitric oxide, serum ECP and airway responsiveness in mild asthmatic children

Abstract

The purpose of the present study was to assess the possible relationships between exhaled nitric oxide (ENO), a circulating marker of eosinophil activation, serum eosinophil cationic protein (SECP), level of airway responsiveness to methacholine and lung function in asthmatic children, as well as to compare these markers between children with and without inhaled steroid therapy.In a cross-sectional study ENO, SECP and bronchial hyperresponsiveness to methacholine were evaluated in a group of 57 asthmatic children (21 without and 36 with regulator inhaled steroid therapy; aged 6±13 yrs).ENO was significantly lower in steroid treated children (p<0.01). No significant differences between steroid treated and untreated children were observed for the provocative concentration of methacholine causing a 20% faill in forced expiratory volume in one second (FEV1; PC20), SECP and FEV1. In the whole study population significant increase correlations were observed between PC20 and SECP (r=-0.329, p=0.013) and between ENO and FEV1% of predicted (r=-0.348, p<0.01). In the group not receiving inhaled steroids the inverse relationship between PC20 and SECP was more evident (r=-0.581, p<0.001). In the steroid-treated group a significant inverse relationship was observed between ENO and FEV1 (r=-0.426, p=0.0011).The level of exhaled nitric oxide and the relationships between lung function, bronchial reactivity and markers of inflammation are different between steroidtreated and untreated asthmatic children. This has implications for the monitoring of asthma in childhood. The relationship between airway inflammation and airway responsiveness has been evaluated by different groups with contrasting results. Some authors [1±6] have found a strong relationship between inflammatory cells in the airway and the level of bronchial responsiveness while others failed to find such a correlation [7±11].Similarly, contrasting results have been found between serum markers of eosinophil activation, in particular serum eosinophil cationic protein (SECP), and the degree of bronchial responsiveness in asthmatic patients [12±15].Recently, the measurement of exhaled nitric oxide (ENO) has been proposed as a noninvasive means for assessing the degree of airway inflammation [16±18]. Some studies have evaluated the effect of treatment with inhaled steroids on the levels of ENO in asthmatic adults [19,20] and one study in children with acute asthma [21]. Furthermore, a few studies have evaluated the relationship of this parameter with the level of airway hyperresponsiveness with contrasting results [22±25].The purpose of the present study was to assess the possible relationship between ENO, a circulating marker of eosinophil activation SECP, level of bronchial hyperresponsiveness (BHR) to methacholine and lung function in asthmatic children, as well as to compare these markers between patients with and without inhaled steroid treatment. Material and methods Subjects and study designFifty-seven children with mild to moderate asthma, clinically st...

Changes of exhaled nitric oxide during steroid treatment of childhood asthma

“…Spacial differences within the lungs are not likely to be responsible for the divergence between eNO and lung function. It has been proposed that FEV1 may reflect the more central airways and that eNO may sample the more distal air spaces [22]. However, the authors did not find a concordance with MMEF (table 1) or the maximum expiratory flow at 25% vital capacity (data not shown).…”

“…Various studies have, so far, investigated lung function and eNO in asthmatic children [20][21][22][23][24][25][26]. In a prospective, open, nonrandomized study the authors recently showed a lack of correlation between eNO and disease severity and only a weak prediction of the physician-recommended inhaled therapy by eNO in children with allergic asthma [14].…”

Exhaled nitric oxide rather than lung function distinguishes preschool children with probable asthma

“…In children with asthma FE NO has been found to correlate with sputum eosinophilia 9 as well as eosinophilia in biopsy specimens, 22 and it is also associated with other clinical characteristics of asthma such as airway hyperresponsiveness, 23 bronchodilator responses, 24 and exercise induced bronchoconstriction. 25 In our patients FE NO was significantly associated with baseline lung function and with bronchodilator responses, although within the groups the correlations were not statistically significant.…”

Guideline-Recommended Fractional Exhaled Nitric Oxide Is a Poor Predictor of Health-care Use Among Inner-city Children and Adolescents Receiving Usual Asthma Care

“…Measurement of F eno as an indicator of pulmonary infl ammation is relatively simple and inexpensive compared with other biomarkers, so there is great interest in the potential role for using F eno data in asthma management. F eno level has been shown to correlate with lung function, sputum eosinophil levels, and methacholine responsiveness, [9][10][11][12][13][14][15][16][17] and, therefore, may provide a noninvasive change of Ն 10 ppb for those with lower categories of infl ammation. We applied this algorithm, modifi ed for pediatric cut points (if F eno level increased by Ն 7 ppb for those with F eno values , 35 ppb or Ն 20% for those with F eno Ն 35 ppb) and found that a "significant" change in F eno level from the previous visit did not predict future health-care use ( Table 5 ).…”

“…These are less likely given prior studies that demonstrate reproducibility of F eno measurements 34,35 and the strong, existing evidence of correlation between eosinophilic airway infl ammation and F eno level. 9,11,[13][14][15][16][17] There were limitations to the study design that warrant consideration. As our study population was limited to children in Baltimore City, results may not be generalizable to other populations.…”