engleski

Non-enzymatic systemic antioxidants as potential biomarkers for chronic obstructive pulmonary disease

Oxidative stress occurs when the balance between oxidants and antioxidants shifts in favour of oxidants. Our aim was to compare levels of non-enzymatic antioxidants in sera of patients with stable chronic obstructive pulmonary disease (COPD) and healthy subjects, and to evaluate their role as potential biomarkers for COPD. The study included 45 healthy subjects and 106 stable COPD patients. COPD patients were additionally subdivided according to disease severity (GOLD stages II-IV) and smoking habits. FEV1 predicted and FEV1/FVC were determined by spirometry. Ceruloplasmin, albumin and transferrin concentrations were determined in serum samples using an automated analyzer. We observed increased ceruloplasmin concentrations in patients compared to controls (0.599  0.266 vs. 0.450  0.139, p = 0.001) while albumin and transferrin concentrations were lower in COPD compared to healthy subjects (39.3  5.8 vs. 49.2  6.9, p < 0.001, and 2.29  0.56 vs. 2.92  0.77, p < 0.001, respectively). Smoking habits did not influence levels of antioxidants tested and neither did disease severity. However, significant differences were found in ceruloplasmin, albumin and transferrin concentrations between controls and GOLD II patients. ROC analysis for ceruloplasmin showed modest performance with area under curve (AUC) of 0.68 [95% confidence interval (CI) 0.60–0.75, p = 0.001], diagnostic sensitivity and specificity of 52.8% and 73.3%, respectively, for the cut-off value of >0.519 g/l. Albumin and transferrin yielded good discriminatory power with AUC of 0.87 (95% CI 0.80–0.92, p < 0.001) and 0.78 (95% CI 0.70–0.84, p < 0.001), respectively. A cut-off value for albumin of ≤43.1 g/l yielded 74.5% sensitivity and 86.1% specificity while the cut-off value for transferrin of ≤2.46 g/l yielded 72.6% sensitivity and 77.8% specificity. The observed changes in ceruloplasmin, albumin and transferrin concentrations suggest disturbed systemic antioxidant capacity in patients with stable COPD. Although those nonenzymatic antioxidants are not disease-specific, their alterations were significant as early as in GOLD II stage, indicating their potential use as biomarkers for the early diagnosis of COPD.

non-enzymatic antioxidants; serum; chronic obstructive lung disease

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