• Delphine Goven, Anne Boutten, Véronique Leçon-Malas, Joëlle Marchal-Sommé, Paul Soler, Jorge Boczkowski, and Marcel Bonay.
• Inserm, U700, Faculté de Médecine-Site Bichat, Université Denis Diderot-Paris 7, Paris, France.
• Plos One. 2010 Jan 1; 5 (5): e10886.

BackgroundFew data concern the pathophysiology of primary spontaneous pneumothorax (PSP), which is associated with alveolar hypoxia/reoxygenation. This study tested the hypothesis that PSP is associated with oxidative stress in lung macrophages. We analysed expression of the oxidative stress marker 4-HNE; the antioxidant and anti-inflammatory proteins heme oxygenase-1 (HO-1), biliverdin reductase (BVR) and heavy chain of ferritin (H-ferritin); and the transcription factors controlling their expression Nrf2 and HIF-1alpha, in lung samples from smoker and nonsmoker patients with PSP (PSP-S and PSP-NS), cigarette smoke being a risk factor of recurrence of the disease.Methodology/Principal FindingsmRNA was assessed by RT-PCR and proteins by western blot, immunohistochemistry and confocal laser analysis. 4-HNE, HO-1, BVR and H-ferritin were increased in macrophages from PSP-S as compared to PSP-NS and controls (C). HO-1 increase was associated with increased expression of HIF-1alpha mRNA and protein in alveolar macrophages in PSP-S patients, whereas Nrf2 was not modified. To understand the regulation of HO-1, BVR and H-ferritin, THP-1 macrophages were exposed to conditions mimicking conditions in C, PSP-S and PSP-NS patients: cigarette smoke condensate (CS) or air exposure followed or not by hypoxia/reoxygenation. Silencing RNA experiments confirmed that HIF-1alpha nuclear translocation was responsible for HO-1, BVR and H-ferritin induction mediated by CS and hypoxia/reoxygenation.Conclusions/SignificancePSP in smokers is associated with lung macrophage oxidative stress. The response to this condition involves HIF-1alpha-mediated induction of HO-1, BVR and H-ferritin.

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