RESUMEN
PURPOSE: Chronic obstructive pulmonary disease is the most common chronic lung disease, which may be caused by different pathological processes, including inflammation. Furthermore, signs of changes in thyroid hormone levels are found in some patients. Deiodinases (DIOs) are selenoproteins (enzymes) involved in the synthesis of thyroid hormones. It has been found that these molecules are involved in inflammatory processes. We carried out this preliminary study to investigate the levels of two deiodinases, i.e. type 1 deiodinase (DIO1) and type 3 deiodinase (DIO3), and their possible association with COPD and specific clinical parameters. PATIENTS AND METHODS: Serum levels of DIO1 and DIO3 as well as lung function parameters were measured in 50 patients suffering from COPD and 30 healthy control subjects. The Mann-Whitney U test and Pearson's correlation coefficient were used to compare and correlate data. RESULTS: Serum levels of DIO1 and DIO3 were significantly elevated in COPD patients (97.9 ± 55.6 versus 28.2 ± 28.3 U/L for DIO1 and 19.6 ± 10.7 versus 6.4 ± 6.3 U/L for DIO3; p < 0.001). No correlation between serum levels of the examined DIOs and other sociodemographic and clinical parameters was identified in this study. CONCLUSION: For the first time we observed that peripheral DIO1 and DIO3 concentrations were elevated in COPD; hence, we may cautiously begin considering these molecules as potential circulating biomarkers of COPD. It may also be beneficial to conduct further studies to confirm and clarify their potential role.