Vitamin E, pulmonary functions, and phagocyte-mediated oxidative stress in smokers and nonsmokers

Relationships among the plasma levels of vitamin E (VE), the numbers and prooxidative activities of circulating phagocytes, serum alpha-l-protease inhibitor (API), and pulmonary functions were investigated in 83 asymptomatic male cigarette smokers and 65 nonsmoking controls. Plasma levels of VE, of cholesterol, and of API were measured using high performance liquid chromatography, spectrophotometry, and nephelometry, respectively, whereas reactive oxidant (ROS) generation by activated blood phagocytes was measured using a whole blood luciginen-enhanced chemiluminescence method. Smoking was associated with significantly increased circulating neutrophil counts (p 0.0001), serum API (p 0.0001) and phagocyte-derived ROS-generation (p 0.0001), and decreased spirometric values (FEV1: p 0.0138 and FEF25-75: p 0.0654). Plasma VE and cholesterol levels were not significantly different between smokers and nonsmokers. However, in smokers both plasma VE and cholesterol correlated significantly and positively with serum API (r 0.24, p 0.03 and r 0.30, p 0.005, respectively), neutrophil counts (r 0.24, p 0.03 and r 0.25, p 0.03, respectively), and phagocyte-derived ROS-generation (r 0.32, p 0.003 and r 0.32, p 0.003, respectively), and significantly and inversely with FEV1 (r -0.23, p 0.03 and r -0.22, p 0.04, respectively) and FEF25-75 (r -0.32, p 0.003 and r -0.26, p 0.02, respectively). In nonsmokers plasma VE, but not cholesterol, was positively correlated with FEV1 (r 0.34, p 0.007) and FEF25-75 (r 0.40, p 0.001). The results suggest that VE protects the lungs of both smokers and nonsmokers and may act as a mobilizable antioxidant in response to smoking-induced oxidative stress.