Abstract
Early recognition of patients with unstable COPD is desired reducing the mortality. Asymmetric and symmetric dimethylarginines (ADMA and SDMA, respectively) are markers of endothelial dysfunction. In addition, increased protein arginine methylation is related to hypoxia. We aimed to compare the serum level of L-arginine, ADMA and SDMA in patients with stable and unstable COPD. Methods: A total of 45 patients with COPD were prospectively investigated. Venous blood was taken for evaluation of biomarkers (L-arginine, ADMA, SDMA and hsCRP). All markers were compared with normal controls (NC, n=64). Beside, capillary blood gas analysis was recorded. Unstable patients were defined based on presence of acute exacerbation (COPD-U, n=12). Statistics: ANOVA, chi-square test and Spearman correlation. Results: Both capillary pO2 and SpO2 were significantly lower (p=0.01) in patients with COPD-U. ADMA and SDMA were significantly higher (p=0.004 and p<0.001, respectively) in COPD-U compared to stable patients, however neither the precursor molecule L-arginine, nor the hsCRP showed significant difference. Both ADMA (AUC: 0.81, p=0.001) and particularly SDMA (AUC: 0.91, p<0.001) with high sensitivity and specificity differed patients with COPD-U. A cut-off for SDMA ≥ 0.57 was found as an independent variable in a regression model to verify COPD-U (OR: 39.2, p=0.001). All markers were significantly higher in patient groups compared to NC. Conclusions: COPD is associated with elevated L-arginine, ADMA and SDMA serum level. In unstable patients, production of ADMA and SDMA are more pronounced probably due to more severe hypoxic insults. Thus methylated arginine derivatives may help in recognition of unstable patients.
- © 2013 ERS
