Pepsin levels and oxidative stress markers in exhaled breath condensate of patients with gastroesophageal reflux disease

AimTo evaluate the pepsin and oxidative stress markers in exhaled breath condensate (EBC) in patients with gastroesophageal reflux disease (GERD).Patients and MethodPatients with a presumptive diagnosis of GERD with recurrent respiratory and gastrointestinal problems aged between 2 and 14 years were included in the study. All patients underwent pH monitoring. Patients with a reflux index (RI) ≥ 4 were assessed as the reflux group, and those with an RO < 4 were assessed as the non-reflux group. Pepsin levels and oxidative stress markers [NO metabolites (NOX) and total sulphydrile (TSH) levels] were measured in the EBC.ResultsThere were 24 patients in the reflux group [RI 17.6 (6.6-46.4)] [median, interquartile range] and 23 in the non-reflux group [RI 0.8 (0.5-1.9) (p < 0.001). Pepsin levels in the EBC were below the level of detection. The median levels of NOx in the EBC of children with reflux [13.7 μmol/L (7.3-24.5)] were lower in than non-reflux group [21.0 μmol/L (14.0-25.2)] (p = 0.034). There was a negative correlation between reflux index and NOX levels in EBC (rs: − 0.331, p = 0.023). In contrast, there was no difference in TSH levels between the reflux and non-reflux groups [37.4 μmol/L (30.2-44.6) vs 40.1 μmol/L (37.4-44.9), respectively, (p > 0.05)].ConclusionDecreased levels of NOX in patients with GER disease suggest increased oxidative stress in airways of these patients.