Systemic and pulmonary oxidative stress in idiopathic pulmonary fibrosis

An oxidant/antioxidant imbalance has been proposed in patients with idiopat hic pulmonary fibrosis (IPF). We tested this hypothesis by measuring variou s parameters of the oxidant/antioxidant balance in the plasma of 12 patient s with IPF (7 nonsmokers and 5 smokers); in the bronchoalveolar lavage flui d (BALF) of 24 patients with IPF (17 nonsmokers and 7 smokers) and 31 healt hy subjects (23 nonsmokers and 8 smokers). The trolox equivalent antioxidan t capacity (TEAC) in plasma and BALF was lower in nonsmoking patients with IPF (plasma 0.55 +/- 0.1 mM, p < .001; BALF 4.8 +/- 1.2 mu M, mean +/- SEM, p < .01), compared with healthy nonsmokers (plasma 1.33 +/- 0.03 mM; BALF 10 +/- 2 mu M). Similar trends in plasma and BALF TEAC were observed in smo king patients with IPF in comparison with healthy smokers. The decrease in BALF TEAC was concomitant with a decrease in BALF protein thiol levels, but the decrease TEAC levels in plasma in IPF patients was not accompanied by a decrease in protein thiol levels. Reduced glutathione (GSH) was lower in BALF in nonsmoking patients with IPF (1.0 +/- 0.1 mu M) compared with healt hy nonsmokers (2.3 +/- 0.2 mu M, p < .001). In contrast, GSH levels were hi gher in smoking patients with IPF (5.2 +/- 1.1 mu M, p < .001) than in nons moking patients. GSSG levels were not different in any of the groups. The l evels of products of lipid peroxidation measured as thiobarbituric acid rea ctive substances (TBARS) in plasma and BALF were significantly increased in both smoking (plasma 2.2 +/- 0.5 mu M, p < .01; BALF 0.18 +/- 0.04 mu M, p < .001), and nonsmoking (plasma 2.1 +/- 0.3 mu M, p < .01; BALF 0.22 +/- 0 .05 mu M, p < .001) IPF patients, compared with healthy nonsmokers (plasma 1.4 +/- 0.3 mu M; BALF 0.05 +/- 0.004 mu M). These data show evidence of ox idant/antioxidant imbalance in the lungs of patients with IPF, which is als o reflected as systemic oxidant stress. (C) 1999 Elsevier Science Inc.