Dynamic Thiol-Disulfide Homeostasis as a Marker for Oxidative Stress in Lung Transplant Candidates.

Objectives: Oxidative stress developing due to oxidant/antioxidant imbalance plays a crucial role in the etiopathogenesis of chronic progressive lung diseases.The condition is typically more severe in lung transplant candidates with end-stage lung disease. Here, we investigated dynamic thiol-disulfide homeostasis as a marker for oxidative stress in lung transplant candidates.

Materials And Methods: The study included 40 patients with end-stage lung disease with indications for lung transplant (candidate group) and 40 healthy controls. Patient demographic data, laboratory results, and thiol-disulfide homeostasis values were recorded. We categorized patients according to their primary diseases and noted clinical measurements of forced expiratory volume in 1 second, forced vital capacity, 6-minute walk test, systolic pulmonary artery pressure, and lung allocation scores.Thiol-disulfide homeostasis parameters were compared before and after transplant.

Results: Demographic characteristics were similar in the candidate and control groups. In the candidate group, native thiol and total thiol levels (antioxidant parameters of thiol-disulfide homeostasis) were significantly lower, whereas disulfide-to-native thiol and disulfide-to-total thiol ratios (oxidant parameters of thiol-disulfide homeostasis) were significantly higher. We observed no significant differences between the disease subgroups in terms of thioldisulfide homeostasis parameters. Moderately significant correlations were shown between the antioxidant markers ofthiol-disulfide homeostasis and the clinical measurements, including the lung allocation scores. Our multiple regression analyses showed that native thiol and total thiol were significant predictive factors to estimate the lung allocation score. During the study period, 6 patients (15%)received lung transplant. There were significant differences in antioxidant parameters ofthiol-disulfide homeostasis in the pre- versus posttransplant periods.

Conclusions: In patients with end-stage lung disease, the dynamic thiol-disulfide homeostasis status is altered in favor of oxidants. Thus, thiol-disulfide homeostasis parameters can be used to detect oxidative stress and estimate lung allocation scores in these patients. Lung transplant may have positive effects on oxidative stress.