Hiroshi Odajima

Exhaled nitric oxide and exercise-induced bronchospasm assessed by FEV1, FEF25-75% in childhood asthma.

The relationship between exhaled nitric oxide (eNO) and bronchial hyperresponsiveness (BHR) should be clarified. The aim of this study was to determine the relationship between eNO and exercise-induced bronchospasm (EIB) by estimation of the each lung parameter in asthmatic children who performed a bicycle ergometer exercise test. Twenty children with asthma were recruited. eNO concentration was examined by the recommended online method. To evaluate BHR, an exercise stress test was performed on a bicycle ergometer. The mean baseline eNO value was significantly correlated with the mean maximum % fall in forced expiratory volume in 1 second (FEV1), forced expiratory flow between 25% and 75% (FEF25-75%) after exercise (r = 0.53, r = 0.65, respectively). eNO in the EIB-positive group was significantly higher than that in the EIB-negative group by assessing FEV1, FEF25−75% (p < 0.005, p = 0.005). We demonstrated that the most important lung parameter assessed the occurrence of EIB by a bicycle ergometer exercise test was not only FEV1 but FEF25−75%, which significantly correlated with eNO. This suggests that not only FEV1 but FEF25−75% can be used to evaluate the correlations between BHR (EIB) and airway inflammation (eNO) in asthmatic children. A low eNO is useful for a negative predictor for EIB.

Effect of inhaled steroid therapy on exhaled nitric oxide and bronchial responsiveness in children with asthma

Inhaled steroid therapy is reported to reduce the level of exhaled nitric oxide (eNO), but the effects of inhaled corticosteroids (ICS) on bronchial hyperresponsiveness (BHR) have been controversial. The aim of this study was to determine the effects of ICS on the relationship between eNO and BHR. Twenty-six children with asthma were recruited, including 14 children who were receiving ICS (ICS group) and 12 who were not (ICS-naive group). The fractional exhaled nitric oxide concentration (FENO) was examined by the recommended online method. To evaluate BHR, an acetylcholine challenge test was performed. In the ICS-naive group, FENO was significantly correlated with PC20 (p < 0.05, r = −0.70), but not in the ICS group. In conclusion, FENO was significantly correlated with BHR in the ICS-naive group, but this relationship was not present in the ICS group. Our results suggest that the use of ICS should be taken into consideration when evaluating the relation between BHR and airway inflammation.

Fetal growth promotion in allergic children

Several in vitro studies have suggested the presence of Th2‐skewed immunity during pregnancy in infants with atopic diseases. Our study indicated that allergic infants showed a higher birth weight and shorter gestational period at birth than those of non‐allergic peers. Moreover, allergic mothers gave birth to neonates whose birth weights and gestational ages were higher and shorter than those of the non‐allergic mothers, respectively. Thus, our data clearly demonstrated the promotion of intrauterine growth, either in the allergic children, or allergic mothers. Such an intrauterine environment favorable for the fetal growth may also accelerate the development of allergic diseases in their offspring that are most probably caused by the Th2‐oriented immunity.