Serum levels of oxidative stress as a marker of disease severity in idiopathic pulmonary fibrosis

Abstract

Background Idiopathic pulmonary fibrosis (IPF) is a fatal illness characterized by progressive fibrosis resulting in severe dyspnea and impairment of lung function. Although the mechanisms by which lung fibrosis develops are not fully ascertained, recent findings suggest that oxidative stress may play an important role in the pathogenesis of tissue fibrosis. Aim To evaluate the oxidative stress in the serum of patients with IPF and to explore the relationship between oxidative stress levels, dyspnea and impairment of lung function. Material and methods Blood samples from 21 untreated patients with IPF, sequentially recruited over a period of 2 years, and 12 controls were analyzed. The level of oxidative stress in the blood was determined through a spectrophotometric procedure (D-ROMs test). FVC and DLCO were measured in all patients. The level of dyspnea was assessed by the Medical Research Council (MRC) chronic dyspnea scale. Results Serum levels of oxidative stress were significantly increased in patients with IPF compared to controls (mean±SEM: 356.8±14 and 201±10 Carratelli units respectively, p<0.001). Oxidative stress was negatively associated with FVC ( p < 0.01 , r = - 0.79 ) and with DLCO ( p < 0.01 , r = - 0.75 ). Furthermore, oxidative stress was significantly correlated with MRC dyspnea score ( p < 0.01 , r = 0.87 ). Oxidative stress measurements were highly reproducible on two consecutive measurements in the same patients. Conclusion The levels of systemic oxidative stress are enhanced in patients with IPF and could provide useful information about the classification of IPF severity. Strategies to reduce the oxidant burden in IPF may be beneficial in reducing the progressive deterioration of these patients.