Expression of redox sensing factor Nrf2 in lung macrophages and type II pneumocytes as a prognostic factor in pneumothorax recurrence.

Background: Primary spontaneous pneumothorax (PSP) is a common clinical problem. However, PSP recurrence is still a major concern. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a protective role against oxidative airway diseases. The aim was to investigate the role of Nrf2 in PSP patients and its correlation with recurrence.
Methods: Eighty-nine patients were enrolled and received wedge resection of lung with identifiable blebs. Nrf2 expression in resected lung tissues was determined by immunohistochemistry (IHC) and correlated with clinicopathological variables. The prognostic value of Nrf2 for incidence-of-recurrence was determined by Kaplan-Meier estimates and the significance of differences was evaluated by the log-rank test.
Results: Nrf2 staining was predominantly observed in alveolar macrophages and type II pneumocytes of PSP patients and correlated with recurrence (P<0.001 and P=0.001, respectively) and PSP location (macrophages, P=0.013). High Nrf2 expression was correlated with better incidence-of-recurrence (macrophages, P=0.003; type II pneumocytes, P=0.003). Moreover, incidence-of-recurrence was better in patients with higher Nrf2 expression, especially those in the age ≤20, male, and non-smoking groups (macrophages, P=0.009, 0.006, and 0.012; type II pneumocytes, P=0.003, 0.011, and 0.010, respectively).
Conclusions: High Nrf2 expression in alveolar macrophages and type II pneumocytes was significantly associated with the decreased recurrence risk and was the independent factor predicting a better incidence-of-recurrence in PSP. Our results suggest that Nrf2 activation in high risk patients may be a potential target for reducing PSP recurrence.
Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.