Plasma total thiol pool in children with asthma: Modulation during montelukast monotherapy

Background: Inflammation, which is a hallmark of asthma, is one of the main sources of oxidative stress in the human body. Thiols are powerful antioxidants that protect cells against the consequences of oxidative stress. We aimed to investigate whether asthma and montelukast monotherapy affect the total plasma thiol pool in children. Methods: A total of 60 children with asthma and 35 healthy controls participated in the study. Group I consisted of newly diagnosed asthmatics who did not have regular anti-asthmatic therapy previously. Group II consisted of patients who had been undertaking montelukast monotherapy regularly for at least 4 months. Plasma total antioxidant status (TAS) and plasma total thiol (PTT) were measured using spectrophotometric methods. Results: Bronchial asthma patients in both groups I and II had decreased median TAS levels compared with the control group (1.59 [interquartile range, 1.04-1.70] and 1.67 [1.50-1.75] vs. 2.98 [2.76-3.16] Trolox equiv./L, respectively; P < 0.001). Group I had decreased PTT concentrations compared with the control group (0.18 [0.16-0.20] vs. 0.21 [0.19-0.22] mmol/L; P < 0.001), and group II had similar PTT levels to the control group (0.20 [0.17-0.22] mmol/L; P > 0.05). In addition, the median TAS and PTT levels for groups I and II were not statistically different (P > 0.05). There was a positive correlation between TAS and PTT levels (rho = 0.38, P < 0.05) in group I. Conclusion: In order to balance the oxidative stress, both TAS and PTT which are markers of the antioxidant system are reduced in children with asthma. Montelukast monotherapy can limit oxidative stress and thus restore PTT levels but not TAS levels in asthmatic children.