A Screening Test to Identify Individual Susceptibility to Oxidant-Induced Respiratory Epithelial Injury

Oxidant injury to the respiratory epithelium is thought to underlie adverse effects of air pollution on respiratory health, with individual susceptibility likely to determine severity of adverse effects. Knowledge of individual susceptibility would facilitate selecting appropriate participants into randomized clinical trials (RCTs) of antioxidant strategies. Growing primary nasal epithelial cells (NECs) into fully differentiated epithelium in air-liquid interface culture, we separated subjects into sensitive or resistant to oxidant injury by the concentration of H₂O₂ required to induce epithelial leak (FITC-dextran leak > 10 μg/mL). Subjects were classified into sensitive (< 25 mM H₂O₂) or resistant (≥ 25 mM H₂O₂) to oxidative stress. However, 10-12 weeks required to obtain this result is too long for use in screening RCT participants. We previously demonstrated that sensitive participants also showed mitochondrial dysfunction at baseline and thus reasoned that measuring mitochondrial function in submerged monolayer cultures would allow more rapid subject classification. NECs from 38 healthy non-smoking adults had mitochondrial function measured using a Seahorse XF analyzer. K-means cluster analysis based on ATP production and basal respiration independently classified participants into sensitive and resistant groups. Full oxidant epithelial challenge confirmed with 100% classification agreement. Our new screening test provides results in 2-3 weeks and is more practical for screening potential participants in RCTs of antioxidant therapies.