Evidence of unexpected oxidative stress in airways of adolescents born very preterm.

Prematurity and its main respiratory complication, bronchopulmonary dysplasia (BPD), are potentially associated with lifelong respiratory morbidities and/or lung function abnormalities. The mechanisms behind these long-term respiratory problems are still unclear. We assessed airway oxidative stress in adolescents born very preterm (≤ 32 gestational weeks) by measuring 8-isoprostane concentration in the exhaled breath condensate (EBC). In addition, the study protocol included spirometry and measuring nitric oxide in the exhaled air (FeNO). The study groups included 34 ex-preterm adolescents with BPD, 18 ex-preterm adolescents without BPD, and 34 healthy controls born at term. Regardless of a history of BPD, the ex-premature adolescents had higher EBC 8-isoprostane levels [BPD: 9.5(7.3–12.2); preterm non-BPD: 10(8.1–16) pg·mL−1)] than the controls [3.2(1.9–6.5) pg·mL−1] (p<0.001). FEV1 was lower in the BPD group [Z-score:−2.1(1.58)] than in the preterm non-BPD individuals [−1.13(1.15)], who showed in turn significantly lower values than the controls [0.18(0.83); p<0.001]. FeNO was similar in the 3 groups (p=0.55). Our data show that, after premature birth, evidence of oxidative stress in the airways may be detected into adolescence, suggesting that long-term respiratory abnormalities after preterm birth may be associated with an ongoing airway disease and not just a stabilized structural lung damage.