Reduction of Eosinophilic Inflammation in the Airways: Discussion
The effects of montelukast on airway eosinophilic inflammation have been reported previously. Although a significant decrease in sputum eosinophils was demonstrated in the previous study, baseline percentages of sputum eosinophils were significantly higher in the placebo group than in the montelukast group. In the present study, none of the baseline parameters, including the percentage of sputum eosinophils, was significantly different between the montelukast and placebo periods and investigated by a crossover design.
Noninvasive assessment of airway inflammation in asthma has been the focus of increased interest in the past 10 years. Although several techniques have been developed, analysis of induced sputum is particularly useful because it is repeatable and can be performed in outpatient clinics. Therefore, analyzing induced sputum is useful for evaluating the response to anti-inflammatory therapy. Although our method for the analysis of sputum cells was different from the one that was reported by Pizzichini et al, sputum eosinophils were analyzed using the same method in the placebo group and montelukast group, and no significant difference in the percentage of sputum eosinophils was observed in the placebo group, suggesting that our method was reliable and reproducible. Buy birthcontrol online Source In the present study, we used this technique to investigate the potential effects of montelukast on airway inflammation and found that sputum eosinophils significantly decreased with montelukast treatment. It has been reported that inhalation of LTE4 resulted in the recruitment of eosinophils into the airway. In addition, LTD4 possessed chemotactic activity for eosinophils in vitro. More recently, an autocrine CysLTs pathway that supports eosinophil survival by inhibiting apoptosis has been revealed. These findings and the results of the present study suggest that CysLTs are released within the airway of asthmatic patients and that mon-telukast inhibits the chemotactic activity of CysLTs for eosinophils and promotes apoptosis, resulting in a decrease in sputum eosinophils.